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{"found_url":"https:\/\/manual.cs50.io\/","crawl_time":1775419502,"first_indexed_time":1600548903,"http_code":200,"src_unparsed":"io,cs50!manual,\/ s443","src_root_hash":"7072350844791920999","history_drop_reason":null,"meta_title":"CS50 Manual Pages","meta_descriptions":[],"attrs_boilerpipe_text":"Manual pages for the C standard library, the C POSIX library, and the CS50 Library for\nthose less comfortable\n.\naio.h\naio_cancel\n-\ncancel an outstanding asynchronous I\/O request\naio_error\n-\nget error status of asynchronous I\/O operation\naio_fsync\n-\nasynchronous file synchronization\naio_init\n-\nasynchronous I\/O initialization\naio_read\n-\nasynchronous read\naio_return\n-\nget return status of asynchronous I\/O operation\naio_suspend\n-\nwait for asynchronous I\/O operation or timeout\naio_write\n-\nasynchronous write\nlio_listio\n-\ninitiate a list of I\/O requests\narpa\/inet.h\nbyteorder\n-\nconvert values between host and network byte order\nhtonl\n-\nconvert values between host and network byte order\nhtons\n-\nconvert values between host and network byte order\ninet_net_ntop\n-\nInternet network number conversion\ninet_net_pton\n-\nInternet network number conversion\ninet_ntop\n-\nconvert IPv4 and IPv6 addresses from binary to text form\ninet_pton\n-\nconvert IPv4 and IPv6 addresses from text to binary form\nntohl\n-\nconvert values between host and network byte order\nntohs\n-\nconvert values between host and network byte order\nassert.h\n_Static_assert\n-\nfail compilation if assertion is false\nassert\n-\nabort the program if assertion is false\nassert_perror\n-\ntest errnum and abort\nstatic_assert\n-\nfail compilation if assertion is false\ncomplex.h\ncabs\n-\nabsolute value of a complex number\ncabsf\n-\nabsolute value of a complex number\ncabsl\n-\nabsolute value of a complex number\ncacos\n-\ncomplex arc cosine\ncacosf\n-\ncomplex arc cosine\ncacosh\n-\ncomplex arc hyperbolic cosine\ncacoshf\n-\ncomplex arc hyperbolic cosine\ncacoshl\n-\ncomplex arc hyperbolic cosine\ncacosl\n-\ncomplex arc cosine\ncarg\n-\ncalculate the complex argument\ncargf\n-\ncalculate the complex argument\ncargl\n-\ncalculate the complex argument\ncasin\n-\ncomplex arc sine\ncasinf\n-\ncomplex arc sine\ncasinh\n-\ncomplex arc sine hyperbolic\ncasinhf\n-\ncomplex arc sine hyperbolic\ncasinhl\n-\ncomplex arc sine hyperbolic\ncasinl\n-\ncomplex arc sine\ncatan\n-\ncomplex arc tangents\ncatanf\n-\ncomplex arc tangents\ncatanh\n-\ncomplex arc tangents hyperbolic\ncatanhf\n-\ncomplex arc tangents hyperbolic\ncatanhl\n-\ncomplex arc tangents hyperbolic\ncatanl\n-\ncomplex arc tangents\nccos\n-\ncomplex cosine function\nccosf\n-\ncomplex cosine function\nccosh\n-\ncomplex hyperbolic cosine\nccoshf\n-\ncomplex hyperbolic cosine\nccoshl\n-\ncomplex hyperbolic cosine\nccosl\n-\ncomplex cosine function\ncexp\n-\ncomplex exponential function\ncexp2\n-\nbase-2 exponent of a complex number\ncexp2f\n-\nbase-2 exponent of a complex number\ncexp2l\n-\nbase-2 exponent of a complex number\ncexpf\n-\ncomplex exponential function\ncexpl\n-\ncomplex exponential function\ncimag\n-\nget imaginary part of a complex number\ncimagf\n-\nget imaginary part of a complex number\ncimagl\n-\nget imaginary part of a complex number\nclog\n-\nnatural logarithm of a complex number\nclog10\n-\nbase-10 logarithm of a complex number\nclog10f\n-\nbase-10 logarithm of a complex number\nclog10l\n-\nbase-10 logarithm of a complex number\nclog2\n-\nbase-2 logarithm of a complex number\nclog2f\n-\nbase-2 logarithm of a complex number\nclog2l\n-\nbase-2 logarithm of a complex number\nclogf\n-\nnatural logarithm of a complex number\nclogl\n-\nnatural logarithm of a complex number\ncomplex\n-\nbasics of complex mathematics\nconj\n-\ncalculate the complex conjugate\nconjf\n-\ncalculate the complex conjugate\nconjl\n-\ncalculate the complex conjugate\ncpow\n-\ncomplex power function\ncpowf\n-\ncomplex power function\ncpowl\n-\ncomplex power function\ncproj\n-\nproject into Riemann Sphere\ncprojf\n-\nproject into Riemann Sphere\ncprojl\n-\nproject into Riemann Sphere\ncreal\n-\nget real part of a complex number\ncrealf\n-\nget real part of a complex number\ncreall\n-\nget real part of a complex number\ncsin\n-\ncomplex sine function\ncsinf\n-\ncomplex sine function\ncsinh\n-\ncomplex hyperbolic sine\ncsinhf\n-\ncomplex hyperbolic sine\ncsinhl\n-\ncomplex hyperbolic sine\ncsinl\n-\ncomplex sine function\ncsqrt\n-\ncomplex square root\ncsqrtf\n-\ncomplex square root\ncsqrtl\n-\ncomplex square root\nctan\n-\ncomplex tangent function\nctanf\n-\ncomplex tangent function\nctanh\n-\ncomplex hyperbolic tangent\nctanhf\n-\ncomplex hyperbolic tangent\nctanhl\n-\ncomplex hyperbolic tangent\nctanl\n-\ncomplex tangent function\nget_char\n-\nprompts user for a line of text from stdin and returns...\nprompt a user for a\nchar\nget_double\n-\nprompts user for a line of text from stdin and returns...\nprompt a user for a\ndouble\nget_float\n-\nprompts user for a line of text from stdin and returns...\nprompt a user for a\nfloat\nget_int\n-\nprompts user for a line of text from stdin and returns...\nprompt a user for an\nint\nget_long\n-\nprompts user for a line of text from stdin and returns...\nprompt a user for an\nlong\nget_long_long\n-\nprompts user for a line of text from stdin and returns...\nget_string\n-\nprompts user for a line of text from stdin and returns...\nprompt a user for a\nstring\nctype.h\nisalnum\n-\ncharacter classification functions\ncheck whether a character is alphanumeric\nisalnum_l\n-\ncharacter classification functions\nisalpha\n-\ncharacter classification functions\ncheck whether a character is alphabetical\nisalpha_l\n-\ncharacter classification functions\nisascii\n-\ncharacter classification functions\nisascii_l\n-\ncharacter classification functions\nisblank\n-\ncharacter classification functions\ncheck whether a character is blank (i.e., a space or tab)\nisblank_l\n-\ncharacter classification functions\niscntrl\n-\ncharacter classification functions\niscntrl_l\n-\ncharacter classification functions\nisdigit\n-\ncharacter classification functions\ncheck whether a character is a digit\nisdigit_l\n-\ncharacter classification functions\nisgraph\n-\ncharacter classification functions\nisgraph_l\n-\ncharacter classification functions\nislower\n-\ncharacter classification functions\ncheck whether a character is lowercase\nislower_l\n-\ncharacter classification functions\nisprint\n-\ncharacter classification functions\nisprint_l\n-\ncharacter classification functions\nispunct\n-\ncharacter classification functions\ncheck whether a character is punctuation\nispunct_l\n-\ncharacter classification functions\nisspace\n-\ncharacter classification functions\ncheck whether a character is whitespace (e.g., a newline, space, or tab)\nisspace_l\n-\ncharacter classification functions\nisupper\n-\ncharacter classification functions\ncheck whether a character is uppercase\nisupper_l\n-\ncharacter classification functions\nisxdigit\n-\ncharacter classification functions\nisxdigit_l\n-\ncharacter classification functions\ntoascii\n-\nconvert character to ASCII\ntolower\n-\nconvert uppercase or lowercase\nconvert a\nchar\nto lowercase\ntolower_l\n-\nconvert uppercase or lowercase\ntoupper\n-\nconvert uppercase or lowercase\nconvert a\nchar\nto uppercase\ntoupper_l\n-\nconvert uppercase or lowercase\ndirent.h\nalphasort\n-\nscan a directory for matching entries\ngetdirentries\n-\nget directory entries in a filesystem-independent format\nreaddir\n-\nread a directory\nreaddir_r\n-\nread a directory\nscandir\n-\nscan a directory for matching entries\nscandirat\n-\nscan a directory for matching entries\nseekdir\n-\nset the position of the next readdir() call in the dir...\ntelldir\n-\nreturn current location in directory stream\nversionsort\n-\nscan a directory for matching entries\ndlfcn.h\ndladdr\n-\ntranslate address to symbolic information\ndladdr1\n-\ntranslate address to symbolic information\ndlclose\n-\nopen and close a shared object\ndlerror\n-\nobtain error diagnostic for functions in the dlopen API\ndlmopen\n-\nopen and close a shared object\ndlopen\n-\nopen and close a shared object\ndlsym\n-\nobtain address of a symbol in a shared object or execu...\ndlvsym\n-\nobtain address of a symbol in a shared object or execu...\nerrno.h\nerrno\n-\nnumber of last error\nprogram_invocation_name\n-\nobtain name used to invoke calling program\nprogram_invocation_short_name\n-\nobtain name used to invoke calling program\nfcntl.h\narm_fadvise\n-\npredeclare an access pattern for file data\narm_fadvise64_64\n-\npredeclare an access pattern for file data\narm_sync_file_range\n-\nsync a file segment with disk\ncreat\n-\nopen and possibly create a file\nfadvise64\n-\npredeclare an access pattern for file data\nfadvise64_64\n-\npredeclare an access pattern for file data\nfallocate\n-\nmanipulate file space\nfcntl\n-\nmanipulate file descriptor\nfcntl64\n-\nmanipulate file descriptor\nname_to_handle_at\n-\nobtain handle for a pathname and open file via a handle\nopen\n-\nopen and possibly create a file\nopen_by_handle_at\n-\nobtain handle for a pathname and open file via a handle\nopenat\n-\nopen and possibly create a file\nposix_fadvise\n-\npredeclare an access pattern for file data\nposix_fallocate\n-\nallocate file space\nreadahead\n-\ninitiate file readahead into page cache\nsplice\n-\nsplice data to\/from a pipe\nsync_file_range\n-\nsync a file segment with disk\nsync_file_range2\n-\nsync a file segment with disk\ntee\n-\nduplicating pipe content\nvmsplice\n-\nsplice user pages to\/from a pipe\nfenv.h\nfeclearexcept\n-\nfloating-point rounding and exception handling\nfedisableexcept\n-\nfloating-point rounding and exception handling\nfeenableexcept\n-\nfloating-point rounding and exception handling\nfegetenv\n-\nfloating-point rounding and exception handling\nfegetexcept\n-\nfloating-point rounding and exception handling\nfegetexceptflag\n-\nfloating-point rounding and exception handling\nfegetround\n-\nfloating-point rounding and exception handling\nfeholdexcept\n-\nfloating-point rounding and exception handling\nfenv\n-\nfloating-point rounding and exception handling\nferaiseexcept\n-\nfloating-point rounding and exception handling\nfesetenv\n-\nfloating-point rounding and exception handling\nfesetexceptflag\n-\nfloating-point rounding and exception handling\nfesetround\n-\nfloating-point rounding and exception handling\nfetestexcept\n-\nfloating-point rounding and exception handling\nfeupdateenv\n-\nfloating-point rounding and exception handling\nfmtmsg.h\naddseverity\n-\nintroduce new severity classes\nfmtmsg\n-\nprint formatted error messages\nfnmatch.h\nfnmatch\n-\nmatch filename or pathname\nftw.h\nftw\n-\nfile tree walk\nnftw\n-\nfile tree walk\nglob.h\nglob\n-\nfind pathnames matching a pattern, free memory from gl...\nglobfree\n-\nfind pathnames matching a pattern, free memory from gl...\ngrp.h\nfgetgrent_r\n-\nget group file entry reentrantly\ngetgrent_r\n-\nget group file entry reentrantly\ngetgrouplist\n-\nget list of groups to which a user belongs\nputgrent\n-\nwrite a group database entry to a file\niconv.h\niconv\n-\nperform character set conversion\niconv_close\n-\ndeallocate descriptor for character set conversion\niconv_open\n-\nallocate descriptor for character set conversion\ninttypes.h\nstrtoimax\n-\nconvert string to integer\nstrtoumax\n-\nconvert string to integer\nlanginfo.h\nnl_langinfo\n-\nquery language and locale information\nnl_langinfo_l\n-\nquery language and locale information\nlibgen.h\nbasename\n-\nparse pathname components\ndirname\n-\nparse pathname components\nlimits.h\nMB_LEN_MAX\n-\nmaximum multibyte length of a character across all loc...\nrealpath\n-\nreturn the canonicalized absolute pathname\nlocale.h\nduplocale\n-\nduplicate a locale object\nfreelocale\n-\ncreate, modify, and free a locale object\nlocale\n-\ndescription of multilanguage support\nlocaleconv\n-\nget numeric formatting information\nnewlocale\n-\ncreate, modify, and free a locale object\nsetlocale\n-\nset the current locale\nuselocale\n-\nset\/get the locale for the calling thread\nmath.h\nacos\n-\narc cosine function\nacosf\n-\narc cosine function\nacosh\n-\ninverse hyperbolic cosine function\nacoshf\n-\ninverse hyperbolic cosine function\nacoshl\n-\ninverse hyperbolic cosine function\nacosl\n-\narc cosine function\nasin\n-\narc sine function\nasinf\n-\narc sine function\nasinh\n-\ninverse hyperbolic sine function\nasinhf\n-\ninverse hyperbolic sine function\nasinhl\n-\ninverse hyperbolic sine function\nasinl\n-\narc sine function\natan\n-\narc tangent function\natan2\n-\narc tangent function of two variables\natan2f\n-\narc tangent function of two variables\natan2l\n-\narc tangent function of two variables\natanf\n-\narc tangent function\natanh\n-\ninverse hyperbolic tangent function\natanhf\n-\ninverse hyperbolic tangent function\natanhl\n-\ninverse hyperbolic tangent function\natanl\n-\narc tangent function\ncbrt\n-\ncube root function\ncbrtf\n-\ncube root function\ncbrtl\n-\ncube root function\nceil\n-\nceiling function: smallest integral value not less tha...\ncalculate the ceiling of a number\nceilf\n-\nceiling function: smallest integral value not less tha...\nceill\n-\nceiling function: smallest integral value not less tha...\ncopysign\n-\ncopy sign of a number\ncopysignf\n-\ncopy sign of a number\ncopysignl\n-\ncopy sign of a number\ncos\n-\ncosine function\ncosf\n-\ncosine function\ncosh\n-\nhyperbolic cosine function\ncoshf\n-\nhyperbolic cosine function\ncoshl\n-\nhyperbolic cosine function\ncosl\n-\ncosine function\ndrem\n-\nfloating-point remainder function\ndremf\n-\nfloating-point remainder function\ndreml\n-\nfloating-point remainder function\nerf\n-\nerror function\nerfc\n-\ncomplementary error function\nerfcf\n-\ncomplementary error function\nerfcl\n-\ncomplementary error function\nerff\n-\nerror function\nerfl\n-\nerror function\nexp\n-\nbase-e exponential function\nexp10\n-\nbase-10 exponential function\nexp10f\n-\nbase-10 exponential function\nexp10l\n-\nbase-10 exponential function\nexp2\n-\nbase-2 exponential function\nexp2f\n-\nbase-2 exponential function\nexp2l\n-\nbase-2 exponential function\nexpf\n-\nbase-e exponential function\nexpl\n-\nbase-e exponential function\nexpm1\n-\nexponential minus 1\nexpm1f\n-\nexponential minus 1\nexpm1l\n-\nexponential minus 1\nfabs\n-\nabsolute value of floating-point number\nfabsf\n-\nabsolute value of floating-point number\nfabsl\n-\nabsolute value of floating-point number\nfdim\n-\npositive difference\nfdimf\n-\npositive difference\nfdiml\n-\npositive difference\nfinite\n-\nBSD floating-point classification functions\nfinitef\n-\nBSD floating-point classification functions\nfinitel\n-\nBSD floating-point classification functions\nfloor\n-\nlargest integral value not greater than argument\ncalculate the floor of a number\nfloorf\n-\nlargest integral value not greater than argument\nfloorl\n-\nlargest integral value not greater than argument\nfma\n-\nfloating-point multiply and add\nfmaf\n-\nfloating-point multiply and add\nfmal\n-\nfloating-point multiply and add\nfmax\n-\ndetermine maximum of two floating-point numbers\nfmaxf\n-\ndetermine maximum of two floating-point numbers\nfmaxl\n-\ndetermine maximum of two floating-point numbers\nfmin\n-\ndetermine minimum of two floating-point numbers\nfminf\n-\ndetermine minimum of two floating-point numbers\nfminl\n-\ndetermine minimum of two floating-point numbers\nfmod\n-\nfloating-point remainder function\nfmodf\n-\nfloating-point remainder function\nfmodl\n-\nfloating-point remainder function\nfpclassify\n-\nfloating-point classification macros\nfrexp\n-\nconvert floating-point number to fractional and integr...\nfrexpf\n-\nconvert floating-point number to fractional and integr...\nfrexpl\n-\nconvert floating-point number to fractional and integr...\ngamma\n-\n(logarithm of the) gamma function\ngammaf\n-\n(logarithm of the) gamma function\ngammal\n-\n(logarithm of the) gamma function\nHUGE_VAL\n-\nfloating-point constants\nHUGE_VALF\n-\nfloating-point constants\nHUGE_VALL\n-\nfloating-point constants\nhypot\n-\nEuclidean distance function\nhypotf\n-\nEuclidean distance function\nhypotl\n-\nEuclidean distance function\nilogb\n-\nget integer exponent of a floating-point value\nilogbf\n-\nget integer exponent of a floating-point value\nilogbl\n-\nget integer exponent of a floating-point value\nINFINITY\n-\nfloating-point constants\nisfinite\n-\nfloating-point classification macros\nisgreater\n-\nfloating-point relational tests without exception for NaN\nisgreaterequal\n-\nfloating-point relational tests without exception for NaN\nisinf\n-\nfloating-point classification macros\nisinff\n-\nBSD floating-point classification functions\nisinfl\n-\nBSD floating-point classification functions\nisless\n-\nfloating-point relational tests without exception for NaN\nislessequal\n-\nfloating-point relational tests without exception for NaN\nislessgreater\n-\nfloating-point relational tests without exception for NaN\nisnan\n-\nfloating-point classification macros\nisnanf\n-\nBSD floating-point classification functions\nisnanl\n-\nBSD floating-point classification functions\nisnormal\n-\nfloating-point classification macros\nisunordered\n-\nfloating-point relational tests without exception for NaN\nj0\n-\nBessel functions of the first kind\nj0f\n-\nBessel functions of the first kind\nj0l\n-\nBessel functions of the first kind\nj1\n-\nBessel functions of the first kind\nj1f\n-\nBessel functions of the first kind\nj1l\n-\nBessel functions of the first kind\njn\n-\nBessel functions of the first kind\njnf\n-\nBessel functions of the first kind\njnl\n-\nBessel functions of the first kind\nldexp\n-\nmultiply floating-point number by integral power of 2\nldexpf\n-\nmultiply floating-point number by integral power of 2\nldexpl\n-\nmultiply floating-point number by integral power of 2\nlgamma\n-\nlog gamma function\nlgamma_r\n-\nlog gamma function\nlgammaf\n-\nlog gamma function\nlgammaf_r\n-\nlog gamma function\nlgammal\n-\nlog gamma function\nlgammal_r\n-\nlog gamma function\nllrint\n-\nround to nearest integer\nllrintf\n-\nround to nearest integer\nllrintl\n-\nround to nearest integer\nllround\n-\nround to nearest integer\nllroundf\n-\nround to nearest integer\nllroundl\n-\nround to nearest integer\nlog\n-\nnatural logarithmic function\nlog10\n-\nbase-10 logarithmic function\nlog10f\n-\nbase-10 logarithmic function\nlog10l\n-\nbase-10 logarithmic function\nlog1p\n-\nlogarithm of 1 plus argument\nlog1pf\n-\nlogarithm of 1 plus argument\nlog1pl\n-\nlogarithm of 1 plus argument\nlog2\n-\nbase-2 logarithmic function\ncalculate the base-2 logarithm of a number\nlog2f\n-\nbase-2 logarithmic function\nlog2l\n-\nbase-2 logarithmic function\nlogb\n-\nget exponent of a floating-point value\nlogbf\n-\nget exponent of a floating-point value\nlogbl\n-\nget exponent of a floating-point value\nlogf\n-\nnatural logarithmic function\nlogl\n-\nnatural logarithmic function\nlrint\n-\nround to nearest integer\nlrintf\n-\nround to nearest integer\nlrintl\n-\nround to nearest integer\nlround\n-\nround to nearest integer\nlroundf\n-\nround to nearest integer\nlroundl\n-\nround to nearest integer\nmath_error\n-\ndetecting errors from mathematical functions\nmatherr\n-\nSVID math library exception handling\nmodf\n-\nextract signed integral and fractional values from flo...\nmodff\n-\nextract signed integral and fractional values from flo...\nmodfl\n-\nextract signed integral and fractional values from flo...\nNAN\n-\nfloating-point constants\nnan\n-\nreturn 'Not a Number'\nnanf\n-\nreturn 'Not a Number'\nnanl\n-\nreturn 'Not a Number'\nnearbyint\n-\nround to nearest integer\nnearbyintf\n-\nround to nearest integer\nnearbyintl\n-\nround to nearest integer\nnextafter\n-\nfloating-point number manipulation\nnextafterf\n-\nfloating-point number manipulation\nnextafterl\n-\nfloating-point number manipulation\nnextdown\n-\nreturn next floating-point number toward positive\/nega...\nnextdownf\n-\nreturn next floating-point number toward positive\/nega...\nnextdownl\n-\nreturn next floating-point number toward positive\/nega...\nnexttoward\n-\nfloating-point number manipulation\nnexttowardf\n-\nfloating-point number manipulation\nnexttowardl\n-\nfloating-point number manipulation\nnextup\n-\nreturn next floating-point number toward positive\/nega...\nnextupf\n-\nreturn next floating-point number toward positive\/nega...\nnextupl\n-\nreturn next floating-point number toward positive\/nega...\npow\n-\npower functions\nraise a number to a power\npow10\n-\nbase-10 power functions\npow10f\n-\nbase-10 power functions\npow10l\n-\nbase-10 power functions\npowf\n-\npower functions\npowl\n-\npower functions\nremainder\n-\nfloating-point remainder function\nremainderf\n-\nfloating-point remainder function\nremainderl\n-\nfloating-point remainder function\nremquo\n-\nremainder and part of quotient\nremquof\n-\nremainder and part of quotient\nremquol\n-\nremainder and part of quotient\nrint\n-\nround to nearest integer\nrintf\n-\nround to nearest integer\nrintl\n-\nround to nearest integer\nround\n-\nround to nearest integer, away from zero\nround a number to the nearest integer\nroundf\n-\nround to nearest integer, away from zero\nroundl\n-\nround to nearest integer, away from zero\nscalb\n-\nmultiply floating-point number by integral power of ra...\nscalbf\n-\nmultiply floating-point number by integral power of ra...\nscalbl\n-\nmultiply floating-point number by integral power of ra...\nscalbln\n-\nmultiply floating-point number by integral power of radix\nscalblnf\n-\nmultiply floating-point number by integral power of radix\nscalblnl\n-\nmultiply floating-point number by integral power of radix\nscalbn\n-\nmultiply floating-point number by integral power of radix\nscalbnf\n-\nmultiply floating-point number by integral power of radix\nscalbnl\n-\nmultiply floating-point number by integral power of radix\nsignbit\n-\ntest sign of a real floating-point number\nsigngam\n-\nlog gamma function\nsignificand\n-\nget mantissa of floating-point number\nsignificandf\n-\nget mantissa of floating-point number\nsignificandl\n-\nget mantissa of floating-point number\nsin\n-\nsine function\nsincos\n-\ncalculate sin and cos simultaneously\nsincosf\n-\ncalculate sin and cos simultaneously\nsincosl\n-\ncalculate sin and cos simultaneously\nsinf\n-\nsine function\nsinh\n-\nhyperbolic sine function\nsinhf\n-\nhyperbolic sine function\nsinhl\n-\nhyperbolic sine function\nsinl\n-\nsine function\nsqrt\n-\nsquare root function\ncalculate the square root of a number\nsqrtf\n-\nsquare root function\nsqrtl\n-\nsquare root function\ntan\n-\ntangent function\ntanf\n-\ntangent function\ntanh\n-\nhyperbolic tangent function\ntanhf\n-\nhyperbolic tangent function\ntanhl\n-\nhyperbolic tangent function\ntanl\n-\ntangent function\ntgamma\n-\ntrue gamma function\ntgammaf\n-\ntrue gamma function\ntgammal\n-\ntrue gamma function\ntrunc\n-\nround to integer, toward zero\ntruncf\n-\nround to integer, toward zero\ntruncl\n-\nround to integer, toward zero\ny0\n-\nBessel functions of the second kind\ny0f\n-\nBessel functions of the second kind\ny0l\n-\nBessel functions of the second kind\ny1\n-\nBessel functions of the second kind\ny1f\n-\nBessel functions of the second kind\ny1l\n-\nBessel functions of the second kind\nyn\n-\nBessel functions of the second kind\nynf\n-\nBessel functions of the second kind\nynl\n-\nBessel functions of the second kind\nmonetary.h\nstrfmon\n-\nconvert monetary value to a string\nstrfmon_l\n-\nconvert monetary value to a string\nmqueue.h\nmq_close\n-\nclose a message queue descriptor\nmq_getattr\n-\nget\/set message queue attributes\nmq_notify\n-\nregister for notification when a message is available\nmq_notify\n-\nregister for notification when a message is available\nmq_open\n-\nopen a message queue\nmq_open\n-\nopen a message queue\nmq_receive\n-\nreceive a message from a message queue\nmq_send\n-\nsend a message to a message queue\nmq_setattr\n-\nget\/set message queue attributes\nmq_timedreceive\n-\nreceive a message from a message queue\nmq_timedreceive\n-\nreceive a message from a message queue\nmq_timedsend\n-\nsend a message to a message queue\nmq_timedsend\n-\nsend a message to a message queue\nmq_unlink\n-\nremove a message queue\nmq_unlink\n-\nremove a message queue\nnet\/if.h\nif_freenameindex\n-\nget network interface names and indexes\nif_indextoname\n-\nmappings between network interface names and indexes\nif_nameindex\n-\nget network interface names and indexes\nif_nametoindex\n-\nmappings between network interface names and indexes\nnetdb.h\nendhostent\n-\nget network host entry\nendnetent\n-\nget network entry\nendnetgrent\n-\nhandle network group entries\nendprotoent\n-\nget protocol entry\nendrpcent\n-\nget RPC entry\nendservent\n-\nget service entry\ngai_cancel\n-\nasynchronous network address and service translation\ngai_error\n-\nasynchronous network address and service translation\ngai_suspend\n-\nasynchronous network address and service translation\ngetaddrinfo_a\n-\nasynchronous network address and service translation\ngethostbyaddr\n-\nget network host entry\ngethostbyaddr_r\n-\nget network host entry\ngethostbyname\n-\nget network host entry\ngethostbyname2\n-\nget network host entry\ngethostbyname2_r\n-\nget network host entry\ngethostbyname_r\n-\nget network host entry\ngethostent\n-\nget network host entry\ngethostent_r\n-\nget network host entry\ngetnetbyaddr\n-\nget network entry\ngetnetbyaddr_r\n-\nget network entry (reentrant)\ngetnetbyname\n-\nget network entry\ngetnetbyname_r\n-\nget network entry (reentrant)\ngetnetent\n-\nget network entry\ngetnetent_r\n-\nget network entry (reentrant)\ngetnetgrent\n-\nhandle network group entries\ngetnetgrent_r\n-\nhandle network group entries\ngetprotobyname\n-\nget protocol entry\ngetprotobyname_r\n-\nget protocol entry (reentrant)\ngetprotobynumber\n-\nget protocol entry\ngetprotobynumber_r\n-\nget protocol entry (reentrant)\ngetprotoent\n-\nget protocol entry\ngetprotoent_r\n-\nget protocol entry (reentrant)\ngetrpcbyname\n-\nget RPC entry\ngetrpcbyname_r\n-\nget RPC entry (reentrant)\ngetrpcbynumber\n-\nget RPC entry\ngetrpcbynumber_r\n-\nget RPC entry (reentrant)\ngetrpcent\n-\nget RPC entry\ngetrpcent_r\n-\nget RPC entry (reentrant)\ngetservbyname\n-\nget service entry\ngetservbyname_r\n-\nget service entry (reentrant)\ngetservbyport\n-\nget service entry\ngetservbyport_r\n-\nget service entry (reentrant)\ngetservent\n-\nget service entry\ngetservent_r\n-\nget service entry (reentrant)\nh_errno\n-\nget network host entry\nherror\n-\nget network host entry\nhstrerror\n-\nget network host entry\ninnetgr\n-\nhandle network group entries\nrexec\n-\nreturn stream to a remote command\nrexec_af\n-\nreturn stream to a remote command\nsethostent\n-\nget network host entry\nsetnetent\n-\nget network entry\nsetnetgrent\n-\nhandle network group entries\nsetprotoent\n-\nget protocol entry\nsetrpcent\n-\nget RPC entry\nsetservent\n-\nget service entry\nnetinet\/in.h\ndn_comp\n-\nresolver routines\ndn_expand\n-\nresolver routines\nres_init\n-\nresolver routines\nres_mkquery\n-\nresolver routines\nres_nclose\n-\nresolver routines\nres_ninit\n-\nresolver routines\nres_nmkquery\n-\nresolver routines\nres_nquery\n-\nresolver routines\nres_nquerydomain\n-\nresolver routines\nres_nsearch\n-\nresolver routines\nres_nsend\n-\nresolver routines\nres_query\n-\nresolver routines\nres_querydomain\n-\nresolver routines\nres_search\n-\nresolver routines\nres_send\n-\nresolver routines\nresolver\n-\nresolver routines\nnl_types.h\ncatclose\n-\nopen\/close a message catalog\ncatgets\n-\nget message from a message catalog\ncatopen\n-\nopen\/close a message catalog\npoll.h\npoll\n-\nwait for some event on a file descriptor\nppoll\n-\nwait for some event on a file descriptor\npthread.h\npthread_attr_destroy\n-\ninitialize and destroy thread attributes object\npthread_attr_getaffinity_np\n-\nset\/get CPU affinity attribute in thread at...\npthread_attr_getdetachstate\n-\nset\/get detach state attribute in thread at...\npthread_attr_getguardsize\n-\nset\/get guard size attribute in thread attrib...\npthread_attr_getinheritsched\n-\nset\/get inherit-scheduler attribute in thr...\npthread_attr_getschedparam\n-\nset\/get scheduling parameter attributes in t...\npthread_attr_getschedpolicy\n-\nset\/get scheduling policy attribute in thre...\npthread_attr_getscope\n-\nset\/get contention scope attribute in thread attr...\npthread_attr_getsigmask_np\n-\nset\/get signal mask attribute in thread attr...\npthread_attr_getstack\n-\nset\/get stack attributes in thread attributes object\npthread_attr_getstackaddr\n-\nset\/get stack address attribute in thread att...\npthread_attr_getstacksize\n-\nset\/get stack size attribute in thread attrib...\npthread_attr_init\n-\ninitialize and destroy thread attributes object\npthread_attr_setaffinity_np\n-\nset\/get CPU affinity attribute in thread at...\npthread_attr_setdetachstate\n-\nset\/get detach state attribute in thread at...\npthread_attr_setguardsize\n-\nset\/get guard size attribute in thread attrib...\npthread_attr_setinheritsched\n-\nset\/get inherit-scheduler attribute in thr...\npthread_attr_setschedparam\n-\nset\/get scheduling parameter attributes in t...\npthread_attr_setschedpolicy\n-\nset\/get scheduling policy attribute in thre...\npthread_attr_setscope\n-\nset\/get contention scope attribute in thread attr...\npthread_attr_setsigmask_np\n-\nset\/get signal mask attribute in thread attr...\npthread_attr_setstack\n-\nset\/get stack attributes in thread attributes object\npthread_attr_setstackaddr\n-\nset\/get stack address attribute in thread att...\npthread_attr_setstacksize\n-\nset\/get stack size attribute in thread attrib...\npthread_cancel\n-\nsend a cancelation request to a thread\npthread_cleanup_pop\n-\npush and pop thread cancelation clean-up handlers\npthread_cleanup_pop_restore_np\n-\npush and pop thread cancelation clean-up...\npthread_cleanup_push\n-\npush and pop thread cancelation clean-up handlers\npthread_cleanup_push_defer_np\n-\npush and pop thread cancelation clean-up ...\npthread_create\n-\ncreate a new thread\npthread_detach\n-\ndetach a thread\npthread_equal\n-\ncompare thread IDs\npthread_exit\n-\nterminate calling thread\npthread_getaffinity_np\n-\nset\/get CPU affinity of a thread\npthread_getattr_default_np\n-\nget or set default thread-creation attributes\npthread_getattr_np\n-\nget attributes of created thread\npthread_getconcurrency\n-\nset\/get the concurrency level\npthread_getcpuclockid\n-\nretrieve ID of a thread's CPU time clock\npthread_getname_np\n-\nset\/get the name of a thread\npthread_getschedparam\n-\nset\/get scheduling policy and parameters of a thread\npthread_join\n-\njoin with a terminated thread\npthread_kill_other_threads_np\n-\nterminate all other threads in process\npthread_mutex_consistent\n-\nmake a robust mutex consistent\npthread_mutex_consistent_np\n-\nmake a robust mutex consistent\npthread_mutexattr_getpshared\n-\nget\/set process-shared mutex attribute\npthread_mutexattr_getrobust\n-\nget and set the robustness attribute of a m...\npthread_mutexattr_getrobust_np\n-\nget and set the robustness attribute of ...\npthread_mutexattr_setpshared\n-\nget\/set process-shared mutex attribute\npthread_mutexattr_setrobust\n-\nget and set the robustness attribute of a m...\npthread_mutexattr_setrobust_np\n-\nget and set the robustness attribute of ...\npthread_rwlockattr_getkind_np\n-\nset\/get the read-write lock kind of the t...\npthread_rwlockattr_setkind_np\n-\nset\/get the read-write lock kind of the t...\npthread_self\n-\nobtain ID of the calling thread\npthread_setaffinity_np\n-\nset\/get CPU affinity of a thread\npthread_setattr_default_np\n-\nget or set default thread-creation attributes\npthread_setcancelstate\n-\nset cancelability state and type\npthread_setcanceltype\n-\nset cancelability state and type\npthread_setconcurrency\n-\nset\/get the concurrency level\npthread_setname_np\n-\nset\/get the name of a thread\npthread_setschedparam\n-\nset\/get scheduling policy and parameters of a thread\npthread_setschedprio\n-\nset scheduling priority of a thread\npthread_spin_destroy\n-\ninitialize or destroy a spin lock\npthread_spin_init\n-\ninitialize or destroy a spin lock\npthread_spin_lock\n-\nlock and unlock a spin lock\npthread_spin_trylock\n-\nlock and unlock a spin lock\npthread_spin_unlock\n-\nlock and unlock a spin lock\npthread_testcancel\n-\nrequest delivery of any pending cancelation request\npthread_timedjoin_np\n-\ntry to join with a terminated thread\npthread_tryjoin_np\n-\ntry to join with a terminated thread\npthread_yield\n-\nyield the processor\npwd.h\nfgetpwent_r\n-\nget passwd file entry reentrantly\ngetpwent_r\n-\nget passwd file entry reentrantly\nregex.h\nregcomp\n-\nPOSIX regex functions\nregerror\n-\nPOSIX regex functions\nregex\n-\nPOSIX regex functions\nregexec\n-\nPOSIX regex functions\nregfree\n-\nPOSIX regex functions\nsched.h\n__clone2\n-\ncreate a child process\nclone\n-\ncreate a child process\nclone2\n-\ncreate a child process\nclone3\n-\ncreate a child process\nCPU_ALLOC\n-\nmacros for manipulating CPU sets\nCPU_ALLOC_SIZE\n-\nmacros for manipulating CPU sets\nCPU_AND\n-\nmacros for manipulating CPU sets\nCPU_AND_S\n-\nmacros for manipulating CPU sets\nCPU_CLR\n-\nmacros for manipulating CPU sets\nCPU_CLR_S\n-\nmacros for manipulating CPU sets\nCPU_COUNT\n-\nmacros for manipulating CPU sets\nCPU_COUNT_S\n-\nmacros for manipulating CPU sets\nCPU_EQUAL\n-\nmacros for manipulating CPU sets\nCPU_EQUAL_S\n-\nmacros for manipulating CPU sets\nCPU_FREE\n-\nmacros for manipulating CPU sets\nCPU_ISSET\n-\nmacros for manipulating CPU sets\nCPU_ISSET_S\n-\nmacros for manipulating CPU sets\nCPU_OR\n-\nmacros for manipulating CPU sets\nCPU_OR_S\n-\nmacros for manipulating CPU sets\nCPU_SET\n-\nmacros for manipulating CPU sets\nCPU_SET_S\n-\nmacros for manipulating CPU sets\nCPU_XOR\n-\nmacros for manipulating CPU sets\nCPU_XOR_S\n-\nmacros for manipulating CPU sets\nCPU_ZERO\n-\nmacros for manipulating CPU sets\nCPU_ZERO_S\n-\nmacros for manipulating CPU sets\ngetcpu\n-\ndetermine CPU and NUMA node on which the calling threa...\nsched_get_priority_max\n-\nget static priority range\nsched_get_priority_min\n-\nget static priority range\nsched_getaffinity\n-\nset and get a thread's CPU affinity mask\nsched_getcpu\n-\ndetermine CPU on which the calling thread is running\nsched_getparam\n-\nset and get scheduling parameters\nsched_getscheduler\n-\nset and get scheduling policy\/parameters\nsched_rr_get_interval\n-\nget the SCHED_RR interval for the named process\nsched_setaffinity\n-\nset and get a thread's CPU affinity mask\nsched_setparam\n-\nset and get scheduling parameters\nsched_setscheduler\n-\nset and get scheduling policy\/parameters\nsched_yield\n-\nyield the processor\nsetns\n-\nreassociate thread with a namespace\nunshare\n-\ndisassociate parts of the process execution context\nsearch.h\nhcreate\n-\nhash table management\nhcreate_r\n-\nhash table management\nhdestroy\n-\nhash table management\nhdestroy_r\n-\nhash table management\nhsearch\n-\nhash table management\nhsearch_r\n-\nhash table management\ninsque\n-\ninsert\/remove an item from a queue\nlfind\n-\nlinear search of an array\nlsearch\n-\nlinear search of an array\nremque\n-\ninsert\/remove an item from a queue\ntdelete\n-\nmanage a binary search tree\ntdestroy\n-\nmanage a binary search tree\ntfind\n-\nmanage a binary search tree\ntsearch\n-\nmanage a binary search tree\ntwalk\n-\nmanage a binary search tree\ntwalk_r\n-\nmanage a binary search tree\nsemaphore.h\nsem_close\n-\nclose a named semaphore\nsem_destroy\n-\ndestroy an unnamed semaphore\nsem_getvalue\n-\nget the value of a semaphore\nsem_init\n-\ninitialize an unnamed semaphore\nsem_open\n-\ninitialize and open a named semaphore\nsem_post\n-\nunlock a semaphore\nsem_timedwait\n-\nlock a semaphore\nsem_trywait\n-\nlock a semaphore\nsem_unlink\n-\nremove a named semaphore\nsem_wait\n-\nlock a semaphore\nsetjmp.h\nlongjmp\n-\nperforming a nonlocal goto\nsetjmp\n-\nperforming a nonlocal goto\nsiglongjmp\n-\nperforming a nonlocal goto\nsigsetjmp\n-\nperforming a nonlocal goto\nsignal.h\nbsd_signal\n-\nsignal handling with BSD semantics\ngsignal\n-\nsoftware signal facility\nkill\n-\nsend signal to a process\nkillpg\n-\nsend signal to a process group\npsiginfo\n-\nprint signal description\npsignal\n-\nprint signal description\npthread_kill\n-\nsend a signal to a thread\npthread_sigmask\n-\nexamine and change mask of blocked signals\npthread_sigqueue\n-\nqueue a signal and data to a thread\nraise\n-\nsend a signal to the caller\nrt_sigaction\n-\nexamine and change a signal action\nrt_sigpending\n-\nexamine pending signals\nrt_sigprocmask\n-\nexamine and change blocked signals\nrt_sigsuspend\n-\nwait for a signal\nrt_sigtimedwait\n-\nsynchronously wait for queued signals\nsigaction\n-\nexamine and change a signal action\nsigaddset\n-\nPOSIX signal set operations\nsigaltstack\n-\nset and\/or get signal stack context\nsigandset\n-\nPOSIX signal set operations\nsigblock\n-\nBSD signal API\nsigdelset\n-\nPOSIX signal set operations\nsigemptyset\n-\nPOSIX signal set operations\nsigfillset\n-\nPOSIX signal set operations\nsiggetmask\n-\nBSD signal API\nsighold\n-\nSystem V signal API\nsigignore\n-\nSystem V signal API\nsiginterrupt\n-\nallow signals to interrupt system calls\nsigisemptyset\n-\nPOSIX signal set operations\nsigismember\n-\nPOSIX signal set operations\nsigmask\n-\nBSD signal API\nsignal\n-\nANSI C signal handling\nsigorset\n-\nPOSIX signal set operations\nsigpause\n-\natomically release blocked signals and wait for interrupt\nsigpending\n-\nexamine pending signals\nsigprocmask\n-\nexamine and change blocked signals\nsigqueue\n-\nqueue a signal and data to a process\nsigrelse\n-\nSystem V signal API\nsigset\n-\nSystem V signal API\nsigsetmask\n-\nBSD signal API\nsigsetops\n-\nPOSIX signal set operations\nsigstack\n-\nset and\/or get signal stack context\nsigsuspend\n-\nwait for a signal\nsigtimedwait\n-\nsynchronously wait for queued signals\nsigvec\n-\nBSD signal API\nsigwait\n-\nwait for a signal\nsigwaitinfo\n-\nsynchronously wait for queued signals\nssignal\n-\nsoftware signal facility\nsysv_signal\n-\nsignal handling with System V semantics\nspawn.h\nposix_spawn\n-\nspawn a process\nposix_spawnp\n-\nspawn a process\nstdarg.h\nstdarg\n-\nvariable argument lists\nva_arg\n-\nvariable argument lists\nva_copy\n-\nvariable argument lists\nva_end\n-\nvariable argument lists\nva_start\n-\nvariable argument lists\nstddef.h\noffsetof\n-\noffset of a structure member\nwcstoimax\n-\nconvert wide-character string to integer\nwcstoumax\n-\nconvert wide-character string to integer\nstdio.h\n__fbufsize\n-\ninterfaces to stdio FILE structure\n__flbf\n-\ninterfaces to stdio FILE structure\n__fpending\n-\ninterfaces to stdio FILE structure\n__fpurge\n-\npurge a stream\n__freadable\n-\ninterfaces to stdio FILE structure\n__freading\n-\ninterfaces to stdio FILE structure\n__fsetlocking\n-\ninterfaces to stdio FILE structure\n__fwritable\n-\ninterfaces to stdio FILE structure\n__fwriting\n-\ninterfaces to stdio FILE structure\n_flushlbf\n-\ninterfaces to stdio FILE structure\naddmntent\n-\nget filesystem descriptor file entry\nasprintf\n-\nprint to allocated string\nclearerr\n-\ncheck and reset stream status\nclearerr_unlocked\n-\nnonlocking stdio functions\nctermid\n-\nget controlling terminal name\ndprintf\n-\nformatted output conversion\nendmntent\n-\nget filesystem descriptor file entry\nfclose\n-\nclose a stream\nclose a file\nfcloseall\n-\nclose all open streams\nfdopen\n-\nstream open functions\nfeof\n-\ncheck and reset stream status\nfeof_unlocked\n-\nnonlocking stdio functions\nferror\n-\ncheck and reset stream status\nferror_unlocked\n-\nnonlocking stdio functions\nfflush\n-\nflush a stream\nfflush_unlocked\n-\nnonlocking stdio functions\nfgetc\n-\ninput of characters and strings\nfgetc_unlocked\n-\nnonlocking stdio functions\nfgetgrent\n-\nget group file entry\nfgetpos\n-\nreposition a stream\nfgetpwent\n-\nget password file entry\nfgets\n-\ninput of characters and strings\nfgets_unlocked\n-\nnonlocking stdio functions\nfgetwc\n-\nread a wide character from a FILE stream\nfgetwc_unlocked\n-\nnonlocking stdio functions\nfgetws_unlocked\n-\nnonlocking stdio functions\nfileno\n-\nobtain file descriptor of a stdio stream\nfileno_unlocked\n-\nnonlocking stdio functions\nflockfile\n-\nlock FILE for stdio\nfmemopen\n-\nopen memory as stream\nfopen\n-\nstream open functions\nopen a file\nfopencookie\n-\nopen a custom stream\nfprintf\n-\nformatted output conversion\nprint to a file\nfpurge\n-\npurge a stream\nfputc\n-\noutput of characters and strings\nfputc_unlocked\n-\nnonlocking stdio functions\nfputs\n-\noutput of characters and strings\nfputs_unlocked\n-\nnonlocking stdio functions\nfputwc\n-\nwrite a wide character to a FILE stream\nfputwc_unlocked\n-\nnonlocking stdio functions\nfputws_unlocked\n-\nnonlocking stdio functions\nfread\n-\nbinary stream input\/output\nread bytes from a file\nfread_unlocked\n-\nnonlocking stdio functions\nfreopen\n-\nstream open functions\nfscanf\n-\ninput FILE format conversion\nget input from a file\nfseek\n-\nreposition a stream\nfseeko\n-\nseek to or report file position\nfsetpos\n-\nreposition a stream\nftell\n-\nreposition a stream\nftello\n-\nseek to or report file position\nftrylockfile\n-\nlock FILE for stdio\nfunlockfile\n-\nlock FILE for stdio\nfwprintf\n-\nformatted wide-character output conversion\nfwrite\n-\nbinary stream input\/output\nwrite bytes to a file\nfwrite_unlocked\n-\nnonlocking stdio functions\ngetc\n-\ninput of characters and strings\ngetc_unlocked\n-\nnonlocking stdio functions\ngetchar\n-\ninput of characters and strings\ngetchar_unlocked\n-\nnonlocking stdio functions\ngetdelim\n-\ndelimited string input\ngetline\n-\ndelimited string input\ngetmntent\n-\nget filesystem descriptor file entry\ngetmntent_r\n-\nget filesystem descriptor file entry\ngets\n-\nget a string from standard input (DEPRECATED)\ngetw\n-\ninput and output of words (ints)\ngetwc\n-\nread a wide character from a FILE stream\ngetwc_unlocked\n-\nnonlocking stdio functions\ngetwchar_unlocked\n-\nnonlocking stdio functions\nhasmntopt\n-\nget filesystem descriptor file entry\nopen_memstream\n-\nopen a dynamic memory buffer stream\nopen_wmemstream\n-\nopen a dynamic memory buffer stream\npclose\n-\npipe stream to or from a process\nperror\n-\nprint a system error message\npopen\n-\npipe stream to or from a process\nprintf\n-\nformatted output conversion\nprint to the screen\nputc\n-\noutput of characters and strings\nputc_unlocked\n-\nnonlocking stdio functions\nputchar\n-\noutput of characters and strings\nputchar_unlocked\n-\nnonlocking stdio functions\nputpwent\n-\nwrite a password file entry\nputs\n-\noutput of characters and strings\nputw\n-\ninput and output of words (ints)\nputwc\n-\nwrite a wide character to a FILE stream\nputwc_unlocked\n-\nnonlocking stdio functions\nputwchar_unlocked\n-\nnonlocking stdio functions\nremove\n-\nremove a file or directory\nrename\n-\nchange the name or location of a file\nrenameat\n-\nchange the name or location of a file\nrenameat2\n-\nchange the name or location of a file\nrewind\n-\nreposition a stream\nscanf\n-\ninput FILE format conversion\nget input from a user\nsetbuf\n-\nstream buffering operations\nsetbuffer\n-\nstream buffering operations\nsetlinebuf\n-\nstream buffering operations\nsetmntent\n-\nget filesystem descriptor file entry\nsetvbuf\n-\nstream buffering operations\nsnprintf\n-\nformatted output conversion\nsprintf\n-\nformatted output conversion\nprint to a string\nsscanf\n-\ninput string format conversion\nstderr\n-\nstandard I\/O streams\nstdin\n-\nstandard I\/O streams\nstdio\n-\nstandard input\/output library functions\nstdio_ext\n-\ninterfaces to stdio FILE structure\nstdout\n-\nstandard I\/O streams\nswprintf\n-\nformatted wide-character output conversion\nsys_errlist\n-\nprint a system error message\nsys_nerr\n-\nprint a system error message\ntempnam\n-\ncreate a name for a temporary file\ntmpfile\n-\ncreate a temporary file\ntmpnam\n-\ncreate a name for a temporary file\ntmpnam_r\n-\ncreate a name for a temporary file\nungetc\n-\ninput of characters and strings\nunlocked_stdio\n-\nnonlocking stdio functions\nvasprintf\n-\nprint to allocated string\nvdprintf\n-\nformatted output conversion\nvfprintf\n-\nformatted output conversion\nvfscanf\n-\ninput FILE format conversion\nvfwprintf\n-\nformatted wide-character output conversion\nvprintf\n-\nformatted output conversion\nvscanf\n-\ninput FILE format conversion\nvsnprintf\n-\nformatted output conversion\nvsprintf\n-\nformatted output conversion\nvsscanf\n-\ninput string format conversion\nvswprintf\n-\nformatted wide-character output conversion\nvwprintf\n-\nformatted wide-character output conversion\nwprintf\n-\nformatted wide-character output conversion\nstdlib.h\na64l\n-\nconvert between long and base-64\nabort\n-\ncause abnormal process termination\nabs\n-\ncompute the absolute value of an integer\naligned_alloc\n-\nallocate aligned memory\narc4random\n-\ncryptographically-secure pseudorandom number generator\narc4random_buf\n-\ncryptographically-secure pseudorandom number generator\narc4random_uniform\n-\ncryptographically-secure pseudorandom number generator\natexit\n-\nregister a function to be called at normal process ter...\natof\n-\nconvert a string to a double\nconvert a\nstring\nto a\nfloat\natoi\n-\nconvert a string to an integer\nconvert a\nstring\nto an\nint\natol\n-\nconvert a string to an integer\nconvert a\nstring\nto a\nlong\natoll\n-\nconvert a string to an integer\natoq\n-\nconvert a string to an integer\nbsearch\n-\nbinary search of a sorted array\ncalloc\n-\nallocate and free dynamic memory\ncanonicalize_file_name\n-\nreturn the canonicalized absolute pathname\ncfree\n-\nfree allocated memory\nclearenv\n-\nclear the environment\ndiv\n-\ncompute quotient and remainder of an integer division\ndrand48\n-\ngenerate uniformly distributed pseudo-random numbers\ndrand48_r\n-\ngenerate uniformly distributed pseudo-random numbers r...\necvt\n-\nconvert a floating-point number to a string\necvt_r\n-\nconvert a floating-point number to a string\nerand48\n-\ngenerate uniformly distributed pseudo-random numbers\nerand48_r\n-\ngenerate uniformly distributed pseudo-random numbers r...\nexit\n-\ncause normal process termination\nfcvt\n-\nconvert a floating-point number to a string\nfcvt_r\n-\nconvert a floating-point number to a string\nfree\n-\nallocate and free dynamic memory\nfree dynamically allocated memory\ngcvt\n-\nconvert a floating-point number to a string\ngetenv\n-\nget an environment variable\ngetloadavg\n-\nget system load averages\ngetpt\n-\nopen a new pseudoterminal master\ngetsubopt\n-\nparse suboption arguments from a string\ngrantpt\n-\ngrant access to the slave pseudoterminal\nimaxabs\n-\ncompute the absolute value of an integer\nimaxdiv\n-\ncompute quotient and remainder of an integer division\ninitstate\n-\nrandom number generator\ninitstate_r\n-\nreentrant random number generator\njrand48\n-\ngenerate uniformly distributed pseudo-random numbers\njrand48_r\n-\ngenerate uniformly distributed pseudo-random numbers r...\nl64a\n-\nconvert between long and base-64\nlabs\n-\ncompute the absolute value of an integer\nlcong48\n-\ngenerate uniformly distributed pseudo-random numbers\nlcong48_r\n-\ngenerate uniformly distributed pseudo-random numbers r...\nldiv\n-\ncompute quotient and remainder of an integer division\nllabs\n-\ncompute the absolute value of an integer\nlldiv\n-\ncompute quotient and remainder of an integer division\nlrand48\n-\ngenerate uniformly distributed pseudo-random numbers\nlrand48_r\n-\ngenerate uniformly distributed pseudo-random numbers r...\nmalloc\n-\nallocate and free dynamic memory\nallocate memory dynamically\nMB_CUR_MAX\n-\nmaximum length of a multibyte character in the current...\nmblen\n-\ndetermine number of bytes in next multibyte character\nmbstowcs\n-\nconvert a multibyte string to a wide-character string\nmbtowc\n-\nconvert a multibyte sequence to a wide character\nmemalign\n-\nallocate aligned memory\nmkdtemp\n-\ncreate a unique temporary directory\nmkostemp\n-\ncreate a unique temporary file\nmkostemps\n-\ncreate a unique temporary file\nmkstemp\n-\ncreate a unique temporary file\nmkstemps\n-\ncreate a unique temporary file\nmktemp\n-\nmake a unique temporary filename\nmrand48\n-\ngenerate uniformly distributed pseudo-random numbers\nmrand48_r\n-\ngenerate uniformly distributed pseudo-random numbers r...\nnrand48\n-\ngenerate uniformly distributed pseudo-random numbers\nnrand48_r\n-\ngenerate uniformly distributed pseudo-random numbers r...\non_exit\n-\nregister a function to be called at normal process ter...\nposix_memalign\n-\nallocate aligned memory\nposix_openpt\n-\nopen a pseudoterminal device\nptsname\n-\nget the name of the slave pseudoterminal\nptsname_r\n-\nget the name of the slave pseudoterminal\nputenv\n-\nchange or add an environment variable\npvalloc\n-\nallocate aligned memory\nqecvt\n-\nconvert a floating-point number to a string\nqecvt_r\n-\nconvert a floating-point number to a string\nqfcvt\n-\nconvert a floating-point number to a string\nqfcvt_r\n-\nconvert a floating-point number to a string\nqgcvt\n-\nconvert a floating-point number to a string\nqsort\n-\nsort an array\nqsort_r\n-\nsort an array\nrand\n-\npseudo-random number generator\nrand_r\n-\npseudo-random number generator\nrandom\n-\nrandom number generator\ngenerate a pseudorandom number\nrandom_r\n-\nreentrant random number generator\nrealloc\n-\nallocate and free dynamic memory\nreallocate memory dynamically\nreallocarray\n-\nallocate and free dynamic memory\nrpmatch\n-\ndetermine if the answer to a question is affirmative o...\nsecure_getenv\n-\nget an environment variable\nseed48\n-\ngenerate uniformly distributed pseudo-random numbers\nseed48_r\n-\ngenerate uniformly distributed pseudo-random numbers r...\nsetenv\n-\nchange or add an environment variable\nsetstate\n-\nrandom number generator\nsetstate_r\n-\nreentrant random number generator\nsrand\n-\npseudo-random number generator\nsrand48\n-\ngenerate uniformly distributed pseudo-random numbers\nsrand48_r\n-\ngenerate uniformly distributed pseudo-random numbers r...\nsrandom\n-\nrandom number generator\nseed pseudorandom number generation\nsrandom_r\n-\nreentrant random number generator\nstrfromd\n-\nconvert a floating-point value into a string\nstrfromf\n-\nconvert a floating-point value into a string\nstrfroml\n-\nconvert a floating-point value into a string\nstrtod\n-\nconvert ASCII string to floating-point number\nstrtof\n-\nconvert ASCII string to floating-point number\nstrtol\n-\nconvert a string to a long integer\nstrtold\n-\nconvert ASCII string to floating-point number\nstrtoll\n-\nconvert a string to a long integer\nstrtoq\n-\nconvert a string to a long integer\nstrtoul\n-\nconvert a string to an unsigned long integer\nstrtoull\n-\nconvert a string to an unsigned long integer\nstrtouq\n-\nconvert a string to an unsigned long integer\nsystem\n-\nexecute a shell command\nunlockpt\n-\nunlock a pseudoterminal master\/slave pair\nunsetenv\n-\nchange or add an environment variable\nvalloc\n-\nallocate aligned memory\nwcstombs\n-\nconvert a wide-character string to a multibyte string\nwctomb\n-\nconvert a wide character to a multibyte sequence\nstring.h\nbstring\n-\nbyte string operations\nmemccpy\n-\ncopy memory area\nmemchr\n-\nscan memory for a character\nmemcmp\n-\ncompare memory areas\nmemcpy\n-\ncopy memory area\nmemfrob\n-\nfrobnicate (obfuscate) a memory area\nmemmem\n-\nlocate a substring\nmemmove\n-\ncopy memory area\nmempcpy\n-\ncopy memory area\nmemrchr\n-\nscan memory for a character\nmemset\n-\nfill memory with a constant byte\nrawmemchr\n-\nscan memory for a character\nsigabbrev_np\n-\nreturn string describing signal\nsigdescr_np\n-\nreturn string describing signal\nstpcpy\n-\ncopy or catenate a string\nstpncpy\n-\nfill a fixed-size buffer with non-null bytes from a st...\nstrcasestr\n-\nlocate a substring\nlocate a substring\nstrcat\n-\ncopy or catenate a string\nstrchr\n-\nlocate character in string\nstrchrnul\n-\nlocate character in string\nstrcmp\n-\ncompare two strings\ncompare two strings\nstrcoll\n-\ncompare two strings using the current locale\nstrcpy\n-\ncopy or catenate a string\ncopy a string\nstrcspn\n-\nget length of a prefix substring\nstrdup\n-\nduplicate a string\nstrdupa\n-\nduplicate a string\nstrerror\n-\nreturn string describing error number\nstrerror_l\n-\nreturn string describing error number\nstrerror_r\n-\nreturn string describing error number\nstrerrordesc_np\n-\nreturn string describing error number\nstrerrorname_np\n-\nreturn string describing error number\nstrfry\n-\nrandomize a string\nstrlen\n-\ncalculate the length of a string\ncalculate the length of a string\nstrncat\n-\nappend non-null bytes from a source array to a string,...\nstrncmp\n-\ncompare two strings\nstrncpy\n-\nfill a fixed-size buffer with non-null bytes from a st...\nstrndup\n-\nduplicate a string\nstrndupa\n-\nduplicate a string\nstrnlen\n-\ndetermine the length of a fixed-size string\nstrpbrk\n-\nsearch a string for any of a set of bytes\nstrrchr\n-\nlocate character in string\nstrsep\n-\nextract token from string\nstrsignal\n-\nreturn string describing signal\nstrspn\n-\nget length of a prefix substring\nstrstr\n-\nlocate a substring\nlocate a substring\nstrtok\n-\nextract tokens from strings\nstrtok_r\n-\nextract tokens from strings\nstrverscmp\n-\ncompare two version strings\nstrxfrm\n-\nstring transformation\nsys_siglist\n-\nreturn string describing signal\nwmempcpy\n-\ncopy memory area\nstrings.h\nbcmp\n-\ncompare byte sequences\nbcopy\n-\ncopy byte sequence\nbzero\n-\nzero a byte string\nexplicit_bzero\n-\nzero a byte string\nffs\n-\nfind first bit set in a word\nffsl\n-\nfind first bit set in a word\nffsll\n-\nfind first bit set in a word\nindex\n-\nlocate character in string\nrindex\n-\nlocate character in string\nstrcasecmp\n-\ncompare two strings ignoring case\ncompare two strings ignoring case\nstring\n-\nstring operations\nstrncasecmp\n-\ncompare two strings ignoring case\nsys\/ipc.h\nftok\n-\nconvert a pathname and a project identifier to a Syste...\nsys\/mman.h\nmadvise\n-\ngive advice about use of memory\nmemfd_create\n-\ncreate an anonymous file\nmincore\n-\ndetermine whether pages are resident in memory\nmlock\n-\nlock and unlock memory\nmlock2\n-\nlock and unlock memory\nmlockall\n-\nlock and unlock memory\nmmap\n-\nmap or unmap files or devices into memory\nmmap64\n-\nmap or unmap files or devices into memory\nmprotect\n-\nset protection on a region of memory\nmremap\n-\nremap a virtual memory address\nmsync\n-\nsynchronize a file with a memory map\nmunlock\n-\nlock and unlock memory\nmunlockall\n-\nlock and unlock memory\nmunmap\n-\nmap or unmap files or devices into memory\npkey_alloc\n-\nallocate or free a protection key\npkey_free\n-\nallocate or free a protection key\npkey_mprotect\n-\nset protection on a region of memory\nposix_madvise\n-\ngive advice about patterns of memory usage\nprocess_madvise\n-\ngive advice about use of memory to a process\nremap_file_pages\n-\ncreate a nonlinear file mapping\nshm_open\n-\ncreate\/open or unlink POSIX shared memory objects\nshm_unlink\n-\ncreate\/open or unlink POSIX shared memory objects\nsys\/msg.h\nmsgctl\n-\nSystem V message control operations\nmsgget\n-\nget a System V message queue identifier\nmsgop\n-\nSystem V message queue operations\nmsgrcv\n-\nSystem V message queue operations\nmsgsnd\n-\nSystem V message queue operations\nsys\/resource.h\ngetpriority\n-\nget\/set program scheduling priority\ngetrlimit\n-\nget\/set resource limits\ngetrusage\n-\nget resource usage\nprlimit\n-\nget\/set resource limits\nprlimit64\n-\nget\/set resource limits\nsetpriority\n-\nget\/set program scheduling priority\nsetrlimit\n-\nget\/set resource limits\nugetrlimit\n-\nget\/set resource limits\nvlimit\n-\nget\/set resource limits\nvtimes\n-\nget resource usage\nsys\/select.h\n_newselect\n-\nsynchronous I\/O multiplexing\nFD_CLR\n-\nsynchronous I\/O multiplexing\nFD_ISSET\n-\nsynchronous I\/O multiplexing\nFD_SET\n-\nsynchronous I\/O multiplexing\nFD_ZERO\n-\nsynchronous I\/O multiplexing\npselect\n-\nsynchronous I\/O multiplexing\npselect6\n-\nsynchronous I\/O multiplexing\nselect\n-\nsynchronous I\/O multiplexing\nsys\/sem.h\nsemctl\n-\nSystem V semaphore control operations\nsemget\n-\nget a System V semaphore set identifier\nsemop\n-\nSystem V semaphore operations\nsemtimedop\n-\nSystem V semaphore operations\nsys\/shm.h\nshmat\n-\nSystem V shared memory operations\nshmctl\n-\nSystem V shared memory control\nshmdt\n-\nSystem V shared memory operations\nshmget\n-\nallocates a System V shared memory segment\nshmop\n-\nSystem V shared memory operations\nsys\/socket.h\naccept\n-\naccept a connection on a socket\naccept4\n-\naccept a connection on a socket\naddress_families\n-\nsocket address families (domains)\nbind\n-\nbind a name to a socket\ncmsg\n-\naccess ancillary data\nCMSG_ALIGN\n-\naccess ancillary data\nCMSG_DATA\n-\naccess ancillary data\nCMSG_FIRSTHDR\n-\naccess ancillary data\nCMSG_LEN\n-\naccess ancillary data\nCMSG_NXTHDR\n-\naccess ancillary data\nCMSG_SPACE\n-\naccess ancillary data\nconnect\n-\ninitiate a connection on a socket\nddp\n-\nLinux AppleTalk protocol implementation\ngetnameinfo\n-\naddress-to-name translation in protocol-independent ma...\ngetpeername\n-\nget name of connected peer socket\ngetsockname\n-\nget socket name\ngetsockopt\n-\nget and set options on sockets\ninet\n-\nInternet address manipulation routines\ninet_addr\n-\nInternet address manipulation routines\ninet_aton\n-\nInternet address manipulation routines\ninet_lnaof\n-\nInternet address manipulation routines\ninet_makeaddr\n-\nInternet address manipulation routines\ninet_netof\n-\nInternet address manipulation routines\ninet_network\n-\nInternet address manipulation routines\ninet_ntoa\n-\nInternet address manipulation routines\nip\n-\nLinux IPv4 protocol implementation\nipv6\n-\nLinux IPv6 protocol implementation\nlisten\n-\nlisten for connections on a socket\npacket\n-\npacket interface on device level\nraw\n-\nLinux IPv4 raw sockets\nrecv\n-\nreceive a message from a socket\nrecvfrom\n-\nreceive a message from a socket\nrecvmmsg\n-\nreceive multiple messages on a socket\nrecvmsg\n-\nreceive a message from a socket\nsend\n-\nsend a message on a socket\nsendmmsg\n-\nsend multiple messages on a socket\nsendmsg\n-\nsend a message on a socket\nsendto\n-\nsend a message on a socket\nsetsockopt\n-\nget and set options on sockets\nshutdown\n-\nshut down part of a full-duplex connection\nsock_diag\n-\nobtaining information about sockets\nsockatmark\n-\ndetermine whether socket is at out-of-band mark\nsocket\n-\ncreate an endpoint for communication\nsocket\n-\nLinux socket interface\nsocketpair\n-\ncreate a pair of connected sockets\ntcp\n-\nTCP protocol\nudp\n-\nUser Datagram Protocol for IPv4\nudplite\n-\nLightweight User Datagram Protocol\nunix\n-\nsockets for local interprocess communication\nvsock\n-\nLinux VSOCK address family\nx25\n-\nITU-T X.25 \/ ISO\/IEC 8208 protocol interface\nsys\/stat.h\nchmod\n-\nchange permissions of a file\nfchmod\n-\nchange permissions of a file\nfchmodat\n-\nchange permissions of a file\nfstat\n-\nget file status\nfstat64\n-\nget file status\nfstatat\n-\nget file status\nfstatat64\n-\nget file status\nfutimens\n-\nchange file timestamps with nanosecond precision\nisfdtype\n-\ntest file type of a file descriptor\nlstat\n-\nget file status\nlstat64\n-\nget file status\nmkdir\n-\ncreate a directory\nmkdirat\n-\ncreate a directory\nmknod\n-\ncreate a special or ordinary file\nmknodat\n-\ncreate a special or ordinary file\nnewfstatat\n-\nget file status\noldfstat\n-\nget file status\noldlstat\n-\nget file status\noldstat\n-\nget file status\nstat\n-\nget file status\nstat64\n-\nget file status\nstatx\n-\nget file status (extended)\numask\n-\nset file mode creation mask\nutimensat\n-\nchange file timestamps with nanosecond precision\nsys\/statvfs.h\nfstatvfs\n-\nget filesystem statistics\nstatvfs\n-\nget filesystem statistics\nsys\/time.h\nadjtime\n-\ncorrect the time to synchronize the system clock\nfutimes\n-\nchange file timestamps\nfutimesat\n-\nchange timestamps of a file relative to a directory fi...\ngetitimer\n-\nget or set value of an interval timer\ngettimeofday\n-\nget \/ set time\nlutimes\n-\nchange file timestamps\nsetitimer\n-\nget or set value of an interval timer\nsettimeofday\n-\nget \/ set time\ntimeradd\n-\ntimeval operations\ntimerclear\n-\ntimeval operations\ntimercmp\n-\ntimeval operations\ntimerisset\n-\ntimeval operations\ntimersub\n-\ntimeval operations\nTIMESPEC_TO_TIMEVAL\n-\nconvert between time structures\nTIMEVAL_TO_TIMESPEC\n-\nconvert between time structures\nsys\/times.h\ntimes\n-\nget process times\nsys\/types.h\nbindresvport\n-\nbind a socket to a privileged IP port\nclosedir\n-\nclose a directory\ndb\n-\ndatabase access methods\ndbopen\n-\ndatabase access methods\ndirfd\n-\nget directory stream file descriptor\nendgrent\n-\nget group file entry\nendpwent\n-\nget password file entry\nfdopendir\n-\nopen a directory\nfreeaddrinfo\n-\nnetwork address and service translation\nfreehostent\n-\nget network hostnames and addresses\nfreeifaddrs\n-\nget interface addresses\nfts\n-\ntraverse a file hierarchy\nfts_children\n-\ntraverse a file hierarchy\nfts_close\n-\ntraverse a file hierarchy\nfts_open\n-\ntraverse a file hierarchy\nfts_read\n-\ntraverse a file hierarchy\nfts_set\n-\ntraverse a file hierarchy\ngai_strerror\n-\nnetwork address and service translation\ngetaddrinfo\n-\nnetwork address and service translation\ngetgrent\n-\nget group file entry\ngetgrgid\n-\nget group file entry\ngetgrgid_r\n-\nget group file entry\ngetgrnam\n-\nget group file entry\ngetgrnam_r\n-\nget group file entry\ngetifaddrs\n-\nget interface addresses\ngetipnodebyaddr\n-\nget network hostnames and addresses\ngetipnodebyname\n-\nget network hostnames and addresses\ngetpw\n-\nreconstruct password line entry\ngetpwent\n-\nget password file entry\ngetpwnam\n-\nget password file entry\ngetpwnam_r\n-\nget password file entry\ngetpwuid\n-\nget password file entry\ngetpwuid_r\n-\nget password file entry\ninitgroups\n-\ninitialize the supplementary group access list\nlseek64\n-\nreposition 64-bit read\/write file offset\nmkfifo\n-\nmake a FIFO special file (a named pipe)\nmkfifoat\n-\nmake a FIFO special file (a named pipe)\nopendir\n-\nopen a directory\nre_comp\n-\nBSD regex functions\nre_exec\n-\nBSD regex functions\nrewinddir\n-\nreset directory stream\nsetgrent\n-\nget group file entry\nsetpwent\n-\nget password file entry\nustat\n-\nget filesystem statistics\nsys\/uio.h\npreadv\n-\nread or write data into multiple buffers\npreadv2\n-\nread or write data into multiple buffers\nprocess_vm_readv\n-\ntransfer data between process address spaces\nprocess_vm_writev\n-\ntransfer data between process address spaces\npwritev\n-\nread or write data into multiple buffers\npwritev2\n-\nread or write data into multiple buffers\nreadv\n-\nread or write data into multiple buffers\nwritev\n-\nread or write data into multiple buffers\nsys\/utsname.h\noldolduname\n-\nget name and information about current kernel\nolduname\n-\nget name and information about current kernel\nuname\n-\nget name and information about current kernel\nsys\/wait.h\nwait\n-\nwait for process to change state\nwait3\n-\nwait for process to change state, BSD style\nwait4\n-\nwait for process to change state, BSD style\nwaitid\n-\nwait for process to change state\nwaitpid\n-\nwait for process to change state\nsyslog.h\ncloselog\n-\nsend messages to the system logger\nopenlog\n-\nsend messages to the system logger\nsetlogmask\n-\nset log priority mask\nsyslog\n-\nsend messages to the system logger\nvsyslog\n-\nsend messages to the system logger\ntermios.h\ncfgetispeed\n-\nget and set terminal attributes, line control, get and...\ncfgetospeed\n-\nget and set terminal attributes, line control, get and...\ncfmakeraw\n-\nget and set terminal attributes, line control, get and...\ncfsetispeed\n-\nget and set terminal attributes, line control, get and...\ncfsetospeed\n-\nget and set terminal attributes, line control, get and...\ncfsetspeed\n-\nget and set terminal attributes, line control, get and...\ntcdrain\n-\nget and set terminal attributes, line control, get and...\ntcflow\n-\nget and set terminal attributes, line control, get and...\ntcflush\n-\nget and set terminal attributes, line control, get and...\ntcgetattr\n-\nget and set terminal attributes, line control, get and...\ntcgetsid\n-\nget session ID\ntcsendbreak\n-\nget and set terminal attributes, line control, get and...\ntcsetattr\n-\nget and set terminal attributes, line control, get and...\ntermios\n-\nget and set terminal attributes, line control, get and...\ntime.h\nasctime\n-\ntransform date and time to broken-down time or ASCII\nasctime_r\n-\ntransform date and time to broken-down time or ASCII\nclock\n-\ndetermine processor time\nclock_getcpuclockid\n-\nobtain ID of a process CPU-time clock\nclock_getres\n-\nclock and time functions\nclock_gettime\n-\nclock and time functions\nclock_nanosleep\n-\nhigh-resolution sleep with specifiable clock\nclock_settime\n-\nclock and time functions\nctime\n-\ntransform date and time to broken-down time or ASCII\nctime_r\n-\ntransform date and time to broken-down time or ASCII\ndaylight\n-\ninitialize time conversion information\ndifftime\n-\ncalculate time difference\ndysize\n-\nget number of days for a given year\ngetdate\n-\nconvert a date-plus-time string to broken-down time\ngetdate_err\n-\nconvert a date-plus-time string to broken-down time\ngetdate_r\n-\nconvert a date-plus-time string to broken-down time\ngmtime\n-\ntransform date and time to broken-down time or ASCII\ngmtime_r\n-\ntransform date and time to broken-down time or ASCII\nlocaltime\n-\ntransform date and time to broken-down time or ASCII\nlocaltime_r\n-\ntransform date and time to broken-down time or ASCII\nmktime\n-\ntransform date and time to broken-down time or ASCII\nnanosleep\n-\nhigh-resolution sleep\nstime\n-\nset time\nstrftime\n-\nformat date and time\nstrftime_l\n-\nformat date and time\nstrptime\n-\nconvert a string representation of time to a time tm s...\ntime\n-\nget time in seconds\nget time in seconds\ntimegm\n-\ninverses of gmtime and localtime\ntimelocal\n-\ninverses of gmtime and localtime\ntimer_create\n-\ncreate a POSIX per-process timer\ntimer_delete\n-\ndelete a POSIX per-process timer\ntimer_getoverrun\n-\nget overrun count for a POSIX per-process timer\ntimer_gettime\n-\narm\/disarm and fetch state of POSIX per-process timer\ntimer_settime\n-\narm\/disarm and fetch state of POSIX per-process timer\ntimezone\n-\ninitialize time conversion information\ntzname\n-\ninitialize time conversion information\ntzset\n-\ninitialize time conversion information\nulimit.h\nulimit\n-\nget and set user limits\nunistd.h\n_Exit\n-\nterminate the calling process\n_exit\n-\nterminate the calling process\n_llseek\n-\nreposition read\/write file offset\n_sysctl\n-\nread\/write system parameters\naccess\n-\ncheck user's permissions for a file\nacct\n-\nswitch process accounting on or off\nalarm\n-\nset an alarm clock for delivery of a signal\narch_prctl\n-\nset architecture-specific thread state\nbrk\n-\nchange data segment size\ncapget\n-\nset\/get capabilities of thread(s)\ncapset\n-\nset\/get capabilities of thread(s)\nchdir\n-\nchange working directory\nchown\n-\nchange ownership of a file\nchown32\n-\nchange ownership of a file\nchroot\n-\nchange root directory\nclose\n-\nclose a file descriptor\nclose_range\n-\nclose all file descriptors in a given range\nconfstr\n-\nget configuration dependent string variables\ncopy_file_range\n-\nCopy a range of data from one file to another\ncuserid\n-\nget username\ndaemon\n-\nrun in the background\ndelete_module\n-\nunload a kernel module\ndup\n-\nduplicate a file descriptor\ndup2\n-\nduplicate a file descriptor\ndup3\n-\nduplicate a file descriptor\neaccess\n-\ncheck effective user's permissions for a file\nencrypt\n-\nencrypt 64-bit messages\nencrypt_r\n-\nencrypt 64-bit messages\nendusershell\n-\nget permitted user shells\neuidaccess\n-\ncheck effective user's permissions for a file\nexec\n-\nexecute a file\nexecl\n-\nexecute a file\nexecle\n-\nexecute a file\nexeclp\n-\nexecute a file\nexecv\n-\nexecute a file\nexecve\n-\nexecute program\nexecveat\n-\nexecute program relative to a directory file descriptor\nexecvp\n-\nexecute a file\nexecvpe\n-\nexecute a file\nexit\n-\nterminate the calling process\nexit_group\n-\nexit all threads in a process\nfaccessat\n-\ncheck user's permissions for a file\nfaccessat2\n-\ncheck user's permissions for a file\nfchdir\n-\nchange working directory\nfchown\n-\nchange ownership of a file\nfchown32\n-\nchange ownership of a file\nfchownat\n-\nchange ownership of a file\nfdatasync\n-\nsynchronize a file's in-core state with storage device\nfexecve\n-\nexecute program specified via file descriptor\nfinit_module\n-\nload a kernel module\nfork\n-\ncreate a child process\nfpathconf\n-\nget configuration values for files\nfsync\n-\nsynchronize a file's in-core state with storage device\nftruncate\n-\ntruncate a file to a specified length\nftruncate64\n-\ntruncate a file to a specified length\nfutex\n-\nfast user-space locking\nget_current_dir_name\n-\nget current working directory\nget_robust_list\n-\nget\/set list of robust futexes\nget_thread_area\n-\nmanipulate thread-local storage information\ngetcwd\n-\nget current working directory\ngetcwd\n-\nget current working directory\ngetdents\n-\nget directory entries\ngetdents64\n-\nget directory entries\ngetdomainname\n-\nget\/set NIS domain name\ngetdtablesize\n-\nget file descriptor table size\ngetegid\n-\nget group identity\ngetegid32\n-\nget group identity\ngetentropy\n-\nfill a buffer with random bytes\ngeteuid\n-\nget user identity\ngeteuid32\n-\nget user identity\ngetgid\n-\nget group identity\ngetgid32\n-\nget group identity\ngetgroups\n-\nget\/set list of supplementary group IDs\ngetgroups32\n-\nget\/set list of supplementary group IDs\ngethostid\n-\nget or set the unique identifier of the current host\ngethostname\n-\nget\/set hostname\ngetlogin\n-\nget username\ngetlogin_r\n-\nget username\ngetopt\n-\nParse command-line options\ngetopt_long\n-\nParse command-line options\ngetopt_long_only\n-\nParse command-line options\ngetpagesize\n-\nget memory page size\ngetpass\n-\nget a password\ngetpgid\n-\nset\/get process group\ngetpgrp\n-\nset\/get process group\ngetpid\n-\nget process identification\ngetppid\n-\nget process identification\ngetresgid\n-\nget real, effective, and saved user\/group IDs\ngetresgid32\n-\nget real, effective, and saved user\/group IDs\ngetresuid\n-\nget real, effective, and saved user\/group IDs\ngetresuid32\n-\nget real, effective, and saved user\/group IDs\ngetsid\n-\nget session ID\ngettid\n-\nget thread identification\ngetuid\n-\nget user identity\ngetuid32\n-\nget user identity\ngetusershell\n-\nget permitted user shells\ngetwd\n-\nget current working directory\ngroup_member\n-\ntest whether a process is in a group\nidle\n-\nmake process 0 idle\ninit_module\n-\nload a kernel module\nio_cancel\n-\ncancel an outstanding asynchronous I\/O operation\nio_destroy\n-\ndestroy an asynchronous I\/O context\nio_getevents\n-\nread asynchronous I\/O events from the completion queue\nioprio_get\n-\nget\/set I\/O scheduling class and priority\nioprio_set\n-\nget\/set I\/O scheduling class and priority\nipc\n-\nSystem V IPC system calls\nisatty\n-\ntest whether a file descriptor refers to a terminal\nkcmp\n-\ncompare two processes to determine if they share a ker...\nkexec_file_load\n-\nload a new kernel for later execution\nkexec_load\n-\nload a new kernel for later execution\nkeyctl\n-\nmanipulate the kernel's key management facility\nklogctl\n-\nread and\/or clear kernel message ring buffer; set cons...\nlchown\n-\nchange ownership of a file\nlchown32\n-\nchange ownership of a file\nlink\n-\nmake a new name for a file\nlinkat\n-\nmake a new name for a file\nllseek\n-\nreposition read\/write file offset\nlockf\n-\napply, test or remove a POSIX lock on an open file\nlookup_dcookie\n-\nreturn a directory entry's path\nlseek\n-\nreposition read\/write file offset\nmembarrier\n-\nissue memory barriers on a set of threads\nmemfd_secret\n-\ncreate an anonymous RAM-based file to access secret me...\nmmap2\n-\nmap files or devices into memory\nmodify_ldt\n-\nget or set a per-process LDT entry\nmount_setattr\n-\nchange properties of a mount or mount tree\nmq_getsetattr\n-\nget\/set message queue attributes\nnice\n-\nchange process priority\nopenat2\n-\nopen and possibly create a file (extended)\noptarg\n-\nParse command-line options\nopterr\n-\nParse command-line options\noptind\n-\nParse command-line options\noptopt\n-\nParse command-line options\npathconf\n-\nget configuration values for files\npause\n-\nwait for signal\nperf_event_open\n-\nset up performance monitoring\npidfd_getfd\n-\nobtain a duplicate of another process's file descriptor\npidfd_open\n-\nobtain a file descriptor that refers to a process\npidfd_send_signal\n-\nsend a signal to a process specified by a file descri...\npipe\n-\ncreate pipe\npipe2\n-\ncreate pipe\npivot_root\n-\nchange the root mount\npread\n-\nread from or write to a file descriptor at a given offset\npread64\n-\nread from or write to a file descriptor at a given offset\nprofil\n-\nexecution time profile\npwrite\n-\nread from or write to a file descriptor at a given offset\npwrite64\n-\nread from or write to a file descriptor at a given offset\nread\n-\nread from a file descriptor\nreaddir\n-\nread directory entry\nreadlink\n-\nread value of a symbolic link\nreadlinkat\n-\nread value of a symbolic link\nreboot\n-\nreboot or enable\/disable Ctrl-Alt-Del\nrmdir\n-\ndelete a directory\nrt_sigqueueinfo\n-\nqueue a signal and data\nrt_tgsigqueueinfo\n-\nqueue a signal and data\ns390_guarded_storage\n-\noperations with z\/Architecture guarded storage fac...\ns390_pci_mmio_read\n-\ntransfer data to\/from PCI MMIO memory page\ns390_pci_mmio_write\n-\ntransfer data to\/from PCI MMIO memory page\ns390_runtime_instr\n-\nenable\/disable s390 CPU run-time instrumentation\ns390_sthyi\n-\nemulate STHYI instruction\nsbrk\n-\nchange data segment size\nsched_getattr\n-\nset and get scheduling policy and attributes\nsched_setattr\n-\nset and get scheduling policy and attributes\nseccomp\n-\noperate on Secure Computing state of the process\nset_robust_list\n-\nget\/set list of robust futexes\nset_thread_area\n-\nmanipulate thread-local storage information\nset_tid_address\n-\nset pointer to thread ID\nsetdomainname\n-\nget\/set NIS domain name\nsetegid\n-\nset effective user or group ID\nseteuid\n-\nset effective user or group ID\nsetgid\n-\nset group identity\nsetgid32\n-\nset group identity\nsetgroups\n-\nget\/set list of supplementary group IDs\nsetgroups32\n-\nget\/set list of supplementary group IDs\nsethostid\n-\nget or set the unique identifier of the current host\nsethostname\n-\nget\/set hostname\nsetkey\n-\nencrypt 64-bit messages\nsetkey_r\n-\nencrypt 64-bit messages\nsetpgid\n-\nset\/get process group\nsetpgrp\n-\nset\/get process group\nsetregid\n-\nset real and\/or effective user or group ID\nsetregid32\n-\nset real and\/or effective user or group ID\nsetresgid\n-\nset real, effective, and saved user or group ID\nsetresgid32\n-\nset real, effective, and saved user or group ID\nsetresuid\n-\nset real, effective, and saved user or group ID\nsetresuid32\n-\nset real, effective, and saved user or group ID\nsetreuid\n-\nset real and\/or effective user or group ID\nsetreuid32\n-\nset real and\/or effective user or group ID\nsetsid\n-\ncreates a session and sets the process group ID\nsetuid\n-\nset user identity\nsetuid32\n-\nset user identity\nsetup\n-\nsetup devices and filesystems, mount root filesystem\nsetusershell\n-\nget permitted user shells\nsgetmask\n-\nmanipulation of signal mask (obsolete)\nsleep\n-\nsleep for a specified number of seconds\nsocketcall\n-\nsocket system calls\nspu_create\n-\ncreate a new spu context\nspu_run\n-\nexecute an SPU context\nssetmask\n-\nmanipulation of signal mask (obsolete)\nsubpage_prot\n-\ndefine a subpage protection for an address range\nswab\n-\nswap adjacent bytes\nsymlink\n-\nmake a new name for a file\nsymlinkat\n-\nmake a new name for a file\nsync\n-\ncommit filesystem caches to disk\nsyncfs\n-\ncommit filesystem caches to disk\nsyscall\n-\nindirect system call\nsysconf\n-\nget configuration information at run time\nsysctl\n-\nread\/write system parameters\nsyslog\n-\nread and\/or clear kernel message ring buffer; set cons...\ntcgetpgrp\n-\nget and set terminal foreground process group\ntcsetpgrp\n-\nget and set terminal foreground process group\ntgkill\n-\nsend a signal to a thread\ntkill\n-\nsend a signal to a thread\ntruncate\n-\ntruncate a file to a specified length\ntruncate64\n-\ntruncate a file to a specified length\nttyname\n-\nreturn name of a terminal\nttyname_r\n-\nreturn name of a terminal\nualarm\n-\nschedule signal after given number of microseconds\nunlink\n-\ndelete a name and possibly the file it refers to\nunlinkat\n-\ndelete a name and possibly the file it refers to\nuselib\n-\nload shared library\nuserfaultfd\n-\ncreate a file descriptor for handling page faults in u...\nusleep\n-\nsuspend execution for microsecond intervals\nvfork\n-\ncreate a child process and block parent\nvhangup\n-\nvirtually hangup the current terminal\nwrite\n-\nwrite to a file descriptor\nutime.h\nutime\n-\nchange file last access and modification times\nutimes\n-\nchange file last access and modification times\nutmpx.h\ngetutmp\n-\ncopy utmp structure to utmpx, and vice versa\ngetutmpx\n-\ncopy utmp structure to utmpx, and vice versa\nwchar.h\nbtowc\n-\nconvert single byte to wide character\nfgetws\n-\nread a wide-character string from a FILE stream\nfputws\n-\nwrite a wide-character string to a FILE stream\nfwide\n-\nset and determine the orientation of a FILE stream\ngetwchar\n-\nread a wide character from standard input\nmbrlen\n-\ndetermine number of bytes in next multibyte character\nmbrtowc\n-\nconvert a multibyte sequence to a wide character\nmbsinit\n-\ntest for initial shift state\nmbsnrtowcs\n-\nconvert a multibyte string to a wide-character string\nmbsrtowcs\n-\nconvert a multibyte string to a wide-character string ...\nputwchar\n-\nwrite a wide character to standard output\nungetwc\n-\npush back a wide character onto a FILE stream\nwcpcpy\n-\ncopy a wide-character string, returning a pointer to i...\nwcpncpy\n-\ncopy a fixed-size string of wide characters, returning...\nwcrtomb\n-\nconvert a wide character to a multibyte sequence\nwcscasecmp\n-\ncompare two wide-character strings, ignoring case\nwcscat\n-\nconcatenate two wide-character strings\nwcschr\n-\nsearch a wide character in a wide-character string\nwcscmp\n-\ncompare two wide-character strings\nwcscpy\n-\ncopy a wide-character string\nwcscspn\n-\nsearch a wide-character string for any of a set of wid...\nwcsdup\n-\nduplicate a wide-character string\nwcslen\n-\ndetermine the length of a wide-character string\nwcsncasecmp\n-\ncompare two fixed-size wide-character strings, ignorin...\nwcsncat\n-\nconcatenate two wide-character strings\nwcsncmp\n-\ncompare two fixed-size wide-character strings\nwcsncpy\n-\ncopy a fixed-size string of wide characters\nwcsnlen\n-\ndetermine the length of a fixed-size wide-character st...\nwcsnrtombs\n-\nconvert a wide-character string to a multibyte string\nwcspbrk\n-\nsearch a wide-character string for any of a set of wid...\nwcsrchr\n-\nsearch a wide character in a wide-character string\nwcsrtombs\n-\nconvert a wide-character string to a multibyte string\nwcsspn\n-\nget length of a prefix wide-character substring\nwcsstr\n-\nlocate a substring in a wide-character string\nwcstok\n-\nsplit wide-character string into tokens\nwcswidth\n-\ndetermine columns needed for a fixed-size wide-charact...\nwctob\n-\ntry to represent a wide character as a single byte\nwcwidth\n-\ndetermine columns needed for a wide character\nwmemchr\n-\nsearch a wide character in a wide-character array\nwmemcmp\n-\ncompare two arrays of wide-characters\nwmemcpy\n-\ncopy an array of wide-characters\nwmemmove\n-\ncopy an array of wide-characters\nwmemset\n-\nfill an array of wide-characters with a constant wide ...\nwctype.h\niswalnum\n-\ntest for alphanumeric wide character\niswalpha\n-\ntest for alphabetic wide character\niswblank\n-\ntest for whitespace wide character\niswcntrl\n-\ntest for control wide character\niswctype\n-\nwide-character classification\niswdigit\n-\ntest for decimal digit wide character\niswgraph\n-\ntest for graphic wide character\niswlower\n-\ntest for lowercase wide character\niswprint\n-\ntest for printing wide character\niswpunct\n-\ntest for punctuation or symbolic wide character\niswspace\n-\ntest for whitespace wide character\niswupper\n-\ntest for uppercase wide character\niswxdigit\n-\ntest for hexadecimal digit wide character\ntowctrans\n-\nwide-character transliteration\ntowlower\n-\nconvert a wide character to lowercase\ntowlower_l\n-\nconvert a wide character to lowercase\ntowupper\n-\nconvert a wide character to uppercase\ntowupper_l\n-\nconvert a wide character to uppercase\nwctrans\n-\nwide-character translation mapping\nwctype\n-\nwide-character classification\nwordexp.h\nwordexp\n-\nperform word expansion like a posix-shell\nwordfree\n-\nperform word expansion like a posix-shell","attrs_markdown":"[CS50 Manual Pages](https:\/\/manual.cs50.io\/)\n\nManual pages for the C standard library, the C POSIX library, and the CS50 Library for [those less comfortable]().\n\n# [aio.h](https:\/\/manual.cs50.io\/#aio.h)\n- [aio\\_cancel](https:\/\/manual.cs50.io\/3\/aio_cancel) - cancel an outstanding asynchronous I\/O request\n- [aio\\_error](https:\/\/manual.cs50.io\/3\/aio_error) - get error status of asynchronous I\/O operation\n- [aio\\_fsync](https:\/\/manual.cs50.io\/3\/aio_fsync) - asynchronous file synchronization\n- [aio\\_init](https:\/\/manual.cs50.io\/3\/aio_init) - asynchronous I\/O initialization\n- [aio\\_read](https:\/\/manual.cs50.io\/3\/aio_read) - asynchronous read\n- [aio\\_return](https:\/\/manual.cs50.io\/3\/aio_return) - get return status of asynchronous I\/O operation\n- [aio\\_suspend](https:\/\/manual.cs50.io\/3\/aio_suspend) - wait for asynchronous I\/O operation or timeout\n- [aio\\_write](https:\/\/manual.cs50.io\/3\/aio_write) - asynchronous write\n- [lio\\_listio](https:\/\/manual.cs50.io\/3\/lio_listio) - initiate a list of I\/O requests\n# [arpa\/inet.h](https:\/\/manual.cs50.io\/#arpa\/inet.h)\n- [byteorder](https:\/\/manual.cs50.io\/3\/byteorder) - convert values between host and network byte order\n- [htonl](https:\/\/manual.cs50.io\/3\/htonl) - convert values between host and network byte order\n- [htons](https:\/\/manual.cs50.io\/3\/htons) - convert values between host and network byte order\n- [inet\\_net\\_ntop](https:\/\/manual.cs50.io\/3\/inet_net_ntop) - Internet network number conversion\n- [inet\\_net\\_pton](https:\/\/manual.cs50.io\/3\/inet_net_pton) - Internet network number conversion\n- [inet\\_ntop](https:\/\/manual.cs50.io\/3\/inet_ntop) - convert IPv4 and IPv6 addresses from binary to text form\n- [inet\\_pton](https:\/\/manual.cs50.io\/3\/inet_pton) - convert IPv4 and IPv6 addresses from text to binary form\n- [ntohl](https:\/\/manual.cs50.io\/3\/ntohl) - convert values between host and network byte order\n- [ntohs](https:\/\/manual.cs50.io\/3\/ntohs) - convert values between host and network byte order\n# [assert.h](https:\/\/manual.cs50.io\/#assert.h)\n- [\\_Static\\_assert](https:\/\/manual.cs50.io\/3\/_Static_assert) - fail compilation if assertion is false\n- [assert](https:\/\/manual.cs50.io\/3\/assert) - abort the program if assertion is false\n- [assert\\_perror](https:\/\/manual.cs50.io\/3\/assert_perror) - test errnum and abort\n- [static\\_assert](https:\/\/manual.cs50.io\/3\/static_assert) - fail compilation if assertion is false\n# [complex.h](https:\/\/manual.cs50.io\/#complex.h)\n- [cabs](https:\/\/manual.cs50.io\/3\/cabs) - absolute value of a complex number\n- [cabsf](https:\/\/manual.cs50.io\/3\/cabsf) - absolute value of a complex number\n- [cabsl](https:\/\/manual.cs50.io\/3\/cabsl) - absolute value of a complex number\n- [cacos](https:\/\/manual.cs50.io\/3\/cacos) - complex arc cosine\n- [cacosf](https:\/\/manual.cs50.io\/3\/cacosf) - complex arc cosine\n- [cacosh](https:\/\/manual.cs50.io\/3\/cacosh) - complex arc hyperbolic cosine\n- [cacoshf](https:\/\/manual.cs50.io\/3\/cacoshf) - complex arc hyperbolic cosine\n- [cacoshl](https:\/\/manual.cs50.io\/3\/cacoshl) - complex arc hyperbolic cosine\n- [cacosl](https:\/\/manual.cs50.io\/3\/cacosl) - complex arc cosine\n- [carg](https:\/\/manual.cs50.io\/3\/carg) - calculate the complex argument\n- [cargf](https:\/\/manual.cs50.io\/3\/cargf) - calculate the complex argument\n- [cargl](https:\/\/manual.cs50.io\/3\/cargl) - calculate the complex argument\n- [casin](https:\/\/manual.cs50.io\/3\/casin) - complex arc sine\n- [casinf](https:\/\/manual.cs50.io\/3\/casinf) - complex arc sine\n- [casinh](https:\/\/manual.cs50.io\/3\/casinh) - complex arc sine hyperbolic\n- [casinhf](https:\/\/manual.cs50.io\/3\/casinhf) - complex arc sine hyperbolic\n- [casinhl](https:\/\/manual.cs50.io\/3\/casinhl) - complex arc sine hyperbolic\n- [casinl](https:\/\/manual.cs50.io\/3\/casinl) - complex arc sine\n- [catan](https:\/\/manual.cs50.io\/3\/catan) - complex arc tangents\n- [catanf](https:\/\/manual.cs50.io\/3\/catanf) - complex arc tangents\n- [catanh](https:\/\/manual.cs50.io\/3\/catanh) - complex arc tangents hyperbolic\n- [catanhf](https:\/\/manual.cs50.io\/3\/catanhf) - complex arc tangents hyperbolic\n- [catanhl](https:\/\/manual.cs50.io\/3\/catanhl) - complex arc tangents hyperbolic\n- [catanl](https:\/\/manual.cs50.io\/3\/catanl) - complex arc tangents\n- [ccos](https:\/\/manual.cs50.io\/3\/ccos) - complex cosine function\n- [ccosf](https:\/\/manual.cs50.io\/3\/ccosf) - complex cosine function\n- [ccosh](https:\/\/manual.cs50.io\/3\/ccosh) - complex hyperbolic cosine\n- [ccoshf](https:\/\/manual.cs50.io\/3\/ccoshf) - complex hyperbolic cosine\n- [ccoshl](https:\/\/manual.cs50.io\/3\/ccoshl) - complex hyperbolic cosine\n- [ccosl](https:\/\/manual.cs50.io\/3\/ccosl) - complex cosine function\n- [cexp](https:\/\/manual.cs50.io\/3\/cexp) - complex exponential function\n- [cexp2](https:\/\/manual.cs50.io\/3\/cexp2) - base-2 exponent of a complex number\n- [cexp2f](https:\/\/manual.cs50.io\/3\/cexp2f) - base-2 exponent of a complex number\n- [cexp2l](https:\/\/manual.cs50.io\/3\/cexp2l) - base-2 exponent of a complex number\n- [cexpf](https:\/\/manual.cs50.io\/3\/cexpf) - complex exponential function\n- [cexpl](https:\/\/manual.cs50.io\/3\/cexpl) - complex exponential function\n- [cimag](https:\/\/manual.cs50.io\/3\/cimag) - get imaginary part of a complex number\n- [cimagf](https:\/\/manual.cs50.io\/3\/cimagf) - get imaginary part of a complex number\n- [cimagl](https:\/\/manual.cs50.io\/3\/cimagl) - get imaginary part of a complex number\n- [clog](https:\/\/manual.cs50.io\/3\/clog) - natural logarithm of a complex number\n- [clog10](https:\/\/manual.cs50.io\/3\/clog10) - base-10 logarithm of a complex number\n- [clog10f](https:\/\/manual.cs50.io\/3\/clog10f) - base-10 logarithm of a complex number\n- [clog10l](https:\/\/manual.cs50.io\/3\/clog10l) - base-10 logarithm of a complex number\n- [clog2](https:\/\/manual.cs50.io\/3\/clog2) - base-2 logarithm of a complex number\n- [clog2f](https:\/\/manual.cs50.io\/3\/clog2f) - base-2 logarithm of a complex number\n- [clog2l](https:\/\/manual.cs50.io\/3\/clog2l) - base-2 logarithm of a complex number\n- [clogf](https:\/\/manual.cs50.io\/3\/clogf) - natural logarithm of a complex number\n- [clogl](https:\/\/manual.cs50.io\/3\/clogl) - natural logarithm of a complex number\n- [complex](https:\/\/manual.cs50.io\/7\/complex) - basics of complex mathematics\n- [conj](https:\/\/manual.cs50.io\/3\/conj) - calculate the complex conjugate\n- [conjf](https:\/\/manual.cs50.io\/3\/conjf) - calculate the complex conjugate\n- [conjl](https:\/\/manual.cs50.io\/3\/conjl) - calculate the complex conjugate\n- [cpow](https:\/\/manual.cs50.io\/3\/cpow) - complex power function\n- [cpowf](https:\/\/manual.cs50.io\/3\/cpowf) - complex power function\n- [cpowl](https:\/\/manual.cs50.io\/3\/cpowl) - complex power function\n- [cproj](https:\/\/manual.cs50.io\/3\/cproj) - project into Riemann Sphere\n- [cprojf](https:\/\/manual.cs50.io\/3\/cprojf) - project into Riemann Sphere\n- [cprojl](https:\/\/manual.cs50.io\/3\/cprojl) - project into Riemann Sphere\n- [creal](https:\/\/manual.cs50.io\/3\/creal) - get real part of a complex number\n- [crealf](https:\/\/manual.cs50.io\/3\/crealf) - get real part of a complex number\n- [creall](https:\/\/manual.cs50.io\/3\/creall) - get real part of a complex number\n- [csin](https:\/\/manual.cs50.io\/3\/csin) - complex sine function\n- [csinf](https:\/\/manual.cs50.io\/3\/csinf) - complex sine function\n- [csinh](https:\/\/manual.cs50.io\/3\/csinh) - complex hyperbolic sine\n- [csinhf](https:\/\/manual.cs50.io\/3\/csinhf) - complex hyperbolic sine\n- [csinhl](https:\/\/manual.cs50.io\/3\/csinhl) - complex hyperbolic sine\n- [csinl](https:\/\/manual.cs50.io\/3\/csinl) - complex sine function\n- [csqrt](https:\/\/manual.cs50.io\/3\/csqrt) - complex square root\n- [csqrtf](https:\/\/manual.cs50.io\/3\/csqrtf) - complex square root\n- [csqrtl](https:\/\/manual.cs50.io\/3\/csqrtl) - complex square root\n- [ctan](https:\/\/manual.cs50.io\/3\/ctan) - complex tangent function\n- [ctanf](https:\/\/manual.cs50.io\/3\/ctanf) - complex tangent function\n- [ctanh](https:\/\/manual.cs50.io\/3\/ctanh) - complex hyperbolic tangent\n- [ctanhf](https:\/\/manual.cs50.io\/3\/ctanhf) - complex hyperbolic tangent\n- [ctanhl](https:\/\/manual.cs50.io\/3\/ctanhl) - complex hyperbolic tangent\n- [ctanl](https:\/\/manual.cs50.io\/3\/ctanl) - complex tangent function\n# [cs50.h](https:\/\/manual.cs50.io\/#cs50.h)\n- [get\\_char](https:\/\/manual.cs50.io\/3\/get_char) - prompts user for a line of text from stdin and returns... prompt a user for a `char`\n- [get\\_double](https:\/\/manual.cs50.io\/3\/get_double) - prompts user for a line of text from stdin and returns... prompt a user for a `double`\n- [get\\_float](https:\/\/manual.cs50.io\/3\/get_float) - prompts user for a line of text from stdin and returns... prompt a user for a `float`\n- [get\\_int](https:\/\/manual.cs50.io\/3\/get_int) - prompts user for a line of text from stdin and returns... prompt a user for an `int`\n- [get\\_long](https:\/\/manual.cs50.io\/3\/get_long) - prompts user for a line of text from stdin and returns... prompt a user for an `long`\n- [get\\_long\\_long](https:\/\/manual.cs50.io\/3\/get_long_long) - prompts user for a line of text from stdin and returns...\n- [get\\_string](https:\/\/manual.cs50.io\/3\/get_string) - prompts user for a line of text from stdin and returns... prompt a user for a `string`\n# [ctype.h](https:\/\/manual.cs50.io\/#ctype.h)\n- [isalnum](https:\/\/manual.cs50.io\/3\/isalnum) - character classification functions check whether a character is alphanumeric\n- [isalnum\\_l](https:\/\/manual.cs50.io\/3\/isalnum_l) - character classification functions\n- [isalpha](https:\/\/manual.cs50.io\/3\/isalpha) - character classification functions check whether a character is alphabetical\n- [isalpha\\_l](https:\/\/manual.cs50.io\/3\/isalpha_l) - character classification functions\n- [isascii](https:\/\/manual.cs50.io\/3\/isascii) - character classification functions\n- [isascii\\_l](https:\/\/manual.cs50.io\/3\/isascii_l) - character classification functions\n- [isblank](https:\/\/manual.cs50.io\/3\/isblank) - character classification functions check whether a character is blank (i.e., a space or tab)\n- [isblank\\_l](https:\/\/manual.cs50.io\/3\/isblank_l) - character classification functions\n- [iscntrl](https:\/\/manual.cs50.io\/3\/iscntrl) - character classification functions\n- [iscntrl\\_l](https:\/\/manual.cs50.io\/3\/iscntrl_l) - character classification functions\n- [isdigit](https:\/\/manual.cs50.io\/3\/isdigit) - character classification functions check whether a character is a digit\n- [isdigit\\_l](https:\/\/manual.cs50.io\/3\/isdigit_l) - character classification functions\n- [isgraph](https:\/\/manual.cs50.io\/3\/isgraph) - character classification functions\n- [isgraph\\_l](https:\/\/manual.cs50.io\/3\/isgraph_l) - character classification functions\n- [islower](https:\/\/manual.cs50.io\/3\/islower) - character classification functions check whether a character is lowercase\n- [islower\\_l](https:\/\/manual.cs50.io\/3\/islower_l) - character classification functions\n- [isprint](https:\/\/manual.cs50.io\/3\/isprint) - character classification functions\n- [isprint\\_l](https:\/\/manual.cs50.io\/3\/isprint_l) - character classification functions\n- [ispunct](https:\/\/manual.cs50.io\/3\/ispunct) - character classification functions check whether a character is punctuation\n- [ispunct\\_l](https:\/\/manual.cs50.io\/3\/ispunct_l) - character classification functions\n- [isspace](https:\/\/manual.cs50.io\/3\/isspace) - character classification functions check whether a character is whitespace (e.g., a newline, space, or tab)\n- [isspace\\_l](https:\/\/manual.cs50.io\/3\/isspace_l) - character classification functions\n- [isupper](https:\/\/manual.cs50.io\/3\/isupper) - character classification functions check whether a character is uppercase\n- [isupper\\_l](https:\/\/manual.cs50.io\/3\/isupper_l) - character classification functions\n- [isxdigit](https:\/\/manual.cs50.io\/3\/isxdigit) - character classification functions\n- [isxdigit\\_l](https:\/\/manual.cs50.io\/3\/isxdigit_l) - character classification functions\n- [toascii](https:\/\/manual.cs50.io\/3\/toascii) - convert character to ASCII\n- [tolower](https:\/\/manual.cs50.io\/3\/tolower) - convert uppercase or lowercase convert a `char` to lowercase\n- [tolower\\_l](https:\/\/manual.cs50.io\/3\/tolower_l) - convert uppercase or lowercase\n- [toupper](https:\/\/manual.cs50.io\/3\/toupper) - convert uppercase or lowercase convert a `char` to uppercase\n- [toupper\\_l](https:\/\/manual.cs50.io\/3\/toupper_l) - convert uppercase or lowercase\n# [dirent.h](https:\/\/manual.cs50.io\/#dirent.h)\n- [alphasort](https:\/\/manual.cs50.io\/3\/alphasort) - scan a directory for matching entries\n- [getdirentries](https:\/\/manual.cs50.io\/3\/getdirentries) - get directory entries in a filesystem-independent format\n- [readdir](https:\/\/manual.cs50.io\/3\/readdir) - read a directory\n- [readdir\\_r](https:\/\/manual.cs50.io\/3\/readdir_r) - read a directory\n- [scandir](https:\/\/manual.cs50.io\/3\/scandir) - scan a directory for matching entries\n- [scandirat](https:\/\/manual.cs50.io\/3\/scandirat) - scan a directory for matching entries\n- [seekdir](https:\/\/manual.cs50.io\/3\/seekdir) - set the position of the next readdir() call in the dir...\n- [telldir](https:\/\/manual.cs50.io\/3\/telldir) - return current location in directory stream\n- [versionsort](https:\/\/manual.cs50.io\/3\/versionsort) - scan a directory for matching entries\n# [dlfcn.h](https:\/\/manual.cs50.io\/#dlfcn.h)\n- [dladdr](https:\/\/manual.cs50.io\/3\/dladdr) - translate address to symbolic information\n- [dladdr1](https:\/\/manual.cs50.io\/3\/dladdr1) - translate address to symbolic information\n- [dlclose](https:\/\/manual.cs50.io\/3\/dlclose) - open and close a shared object\n- [dlerror](https:\/\/manual.cs50.io\/3\/dlerror) - obtain error diagnostic for functions in the dlopen API\n- [dlmopen](https:\/\/manual.cs50.io\/3\/dlmopen) - open and close a shared object\n- [dlopen](https:\/\/manual.cs50.io\/3\/dlopen) - open and close a shared object\n- [dlsym](https:\/\/manual.cs50.io\/3\/dlsym) - obtain address of a symbol in a shared object or execu...\n- [dlvsym](https:\/\/manual.cs50.io\/3\/dlvsym) - obtain address of a symbol in a shared object or execu...\n# [errno.h](https:\/\/manual.cs50.io\/#errno.h)\n- [errno](https:\/\/manual.cs50.io\/3\/errno) - number of last error\n- [program\\_invocation\\_name](https:\/\/manual.cs50.io\/3\/program_invocation_name) - obtain name used to invoke calling program\n- [program\\_invocation\\_short\\_name](https:\/\/manual.cs50.io\/3\/program_invocation_short_name) - obtain name used to invoke calling program\n# [fcntl.h](https:\/\/manual.cs50.io\/#fcntl.h)\n- [arm\\_fadvise](https:\/\/manual.cs50.io\/2\/arm_fadvise) - predeclare an access pattern for file data\n- [arm\\_fadvise64\\_64](https:\/\/manual.cs50.io\/2\/arm_fadvise64_64) - predeclare an access pattern for file data\n- [arm\\_sync\\_file\\_range](https:\/\/manual.cs50.io\/2\/arm_sync_file_range) - sync a file segment with disk\n- [creat](https:\/\/manual.cs50.io\/2\/creat) - open and possibly create a file\n- [fadvise64](https:\/\/manual.cs50.io\/2\/fadvise64) - predeclare an access pattern for file data\n- [fadvise64\\_64](https:\/\/manual.cs50.io\/2\/fadvise64_64) - predeclare an access pattern for file data\n- [fallocate](https:\/\/manual.cs50.io\/2\/fallocate) - manipulate file space\n- [fcntl](https:\/\/manual.cs50.io\/2\/fcntl) - manipulate file descriptor\n- [fcntl64](https:\/\/manual.cs50.io\/2\/fcntl64) - manipulate file descriptor\n- [name\\_to\\_handle\\_at](https:\/\/manual.cs50.io\/2\/name_to_handle_at) - obtain handle for a pathname and open file via a handle\n- [open](https:\/\/manual.cs50.io\/2\/open) - open and possibly create a file\n- [open\\_by\\_handle\\_at](https:\/\/manual.cs50.io\/2\/open_by_handle_at) - obtain handle for a pathname and open file via a handle\n- [openat](https:\/\/manual.cs50.io\/2\/openat) - open and possibly create a file\n- [posix\\_fadvise](https:\/\/manual.cs50.io\/2\/posix_fadvise) - predeclare an access pattern for file data\n- [posix\\_fallocate](https:\/\/manual.cs50.io\/3\/posix_fallocate) - allocate file space\n- [readahead](https:\/\/manual.cs50.io\/2\/readahead) - initiate file readahead into page cache\n- [splice](https:\/\/manual.cs50.io\/2\/splice) - splice data to\/from a pipe\n- [sync\\_file\\_range](https:\/\/manual.cs50.io\/2\/sync_file_range) - sync a file segment with disk\n- [sync\\_file\\_range2](https:\/\/manual.cs50.io\/2\/sync_file_range2) - sync a file segment with disk\n- [tee](https:\/\/manual.cs50.io\/2\/tee) - duplicating pipe content\n- [vmsplice](https:\/\/manual.cs50.io\/2\/vmsplice) - splice user pages to\/from a pipe\n# [fenv.h](https:\/\/manual.cs50.io\/#fenv.h)\n- [feclearexcept](https:\/\/manual.cs50.io\/3\/feclearexcept) - floating-point rounding and exception handling\n- [fedisableexcept](https:\/\/manual.cs50.io\/3\/fedisableexcept) - floating-point rounding and exception handling\n- [feenableexcept](https:\/\/manual.cs50.io\/3\/feenableexcept) - floating-point rounding and exception handling\n- [fegetenv](https:\/\/manual.cs50.io\/3\/fegetenv) - floating-point rounding and exception handling\n- [fegetexcept](https:\/\/manual.cs50.io\/3\/fegetexcept) - floating-point rounding and exception handling\n- [fegetexceptflag](https:\/\/manual.cs50.io\/3\/fegetexceptflag) - floating-point rounding and exception handling\n- [fegetround](https:\/\/manual.cs50.io\/3\/fegetround) - floating-point rounding and exception handling\n- [feholdexcept](https:\/\/manual.cs50.io\/3\/feholdexcept) - floating-point rounding and exception handling\n- [fenv](https:\/\/manual.cs50.io\/3\/fenv) - floating-point rounding and exception handling\n- [feraiseexcept](https:\/\/manual.cs50.io\/3\/feraiseexcept) - floating-point rounding and exception handling\n- [fesetenv](https:\/\/manual.cs50.io\/3\/fesetenv) - floating-point rounding and exception handling\n- [fesetexceptflag](https:\/\/manual.cs50.io\/3\/fesetexceptflag) - floating-point rounding and exception handling\n- [fesetround](https:\/\/manual.cs50.io\/3\/fesetround) - floating-point rounding and exception handling\n- [fetestexcept](https:\/\/manual.cs50.io\/3\/fetestexcept) - floating-point rounding and exception handling\n- [feupdateenv](https:\/\/manual.cs50.io\/3\/feupdateenv) - floating-point rounding and exception handling\n# [fmtmsg.h](https:\/\/manual.cs50.io\/#fmtmsg.h)\n- [addseverity](https:\/\/manual.cs50.io\/3\/addseverity) - introduce new severity classes\n- [fmtmsg](https:\/\/manual.cs50.io\/3\/fmtmsg) - print formatted error messages\n# [fnmatch.h](https:\/\/manual.cs50.io\/#fnmatch.h)\n- [fnmatch](https:\/\/manual.cs50.io\/3\/fnmatch) - match filename or pathname\n# [ftw.h](https:\/\/manual.cs50.io\/#ftw.h)\n- [ftw](https:\/\/manual.cs50.io\/3\/ftw) - file tree walk\n- [nftw](https:\/\/manual.cs50.io\/3\/nftw) - file tree walk\n# [glob.h](https:\/\/manual.cs50.io\/#glob.h)\n- [glob](https:\/\/manual.cs50.io\/3\/glob) - find pathnames matching a pattern, free memory from gl...\n- [globfree](https:\/\/manual.cs50.io\/3\/globfree) - find pathnames matching a pattern, free memory from gl...\n# [grp.h](https:\/\/manual.cs50.io\/#grp.h)\n- [fgetgrent\\_r](https:\/\/manual.cs50.io\/3\/fgetgrent_r) - get group file entry reentrantly\n- [getgrent\\_r](https:\/\/manual.cs50.io\/3\/getgrent_r) - get group file entry reentrantly\n- [getgrouplist](https:\/\/manual.cs50.io\/3\/getgrouplist) - get list of groups to which a user belongs\n- [putgrent](https:\/\/manual.cs50.io\/3\/putgrent) - write a group database entry to a file\n# [iconv.h](https:\/\/manual.cs50.io\/#iconv.h)\n- [iconv](https:\/\/manual.cs50.io\/3\/iconv) - perform character set conversion\n- [iconv\\_close](https:\/\/manual.cs50.io\/3\/iconv_close) - deallocate descriptor for character set conversion\n- [iconv\\_open](https:\/\/manual.cs50.io\/3\/iconv_open) - allocate descriptor for character set conversion\n# [inttypes.h](https:\/\/manual.cs50.io\/#inttypes.h)\n- [strtoimax](https:\/\/manual.cs50.io\/3\/strtoimax) - convert string to integer\n- [strtoumax](https:\/\/manual.cs50.io\/3\/strtoumax) - convert string to integer\n# [langinfo.h](https:\/\/manual.cs50.io\/#langinfo.h)\n- [nl\\_langinfo](https:\/\/manual.cs50.io\/3\/nl_langinfo) - query language and locale information\n- [nl\\_langinfo\\_l](https:\/\/manual.cs50.io\/3\/nl_langinfo_l) - query language and locale information\n# [libgen.h](https:\/\/manual.cs50.io\/#libgen.h)\n- [basename](https:\/\/manual.cs50.io\/3\/basename) - parse pathname components\n- [dirname](https:\/\/manual.cs50.io\/3\/dirname) - parse pathname components\n# [limits.h](https:\/\/manual.cs50.io\/#limits.h)\n- [MB\\_LEN\\_MAX](https:\/\/manual.cs50.io\/3\/MB_LEN_MAX) - maximum multibyte length of a character across all loc...\n- [realpath](https:\/\/manual.cs50.io\/3\/realpath) - return the canonicalized absolute pathname\n# [locale.h](https:\/\/manual.cs50.io\/#locale.h)\n- [duplocale](https:\/\/manual.cs50.io\/3\/duplocale) - duplicate a locale object\n- [freelocale](https:\/\/manual.cs50.io\/3\/freelocale) - create, modify, and free a locale object\n- [locale](https:\/\/manual.cs50.io\/7\/locale) - description of multilanguage support\n- [localeconv](https:\/\/manual.cs50.io\/3\/localeconv) - get numeric formatting information\n- [newlocale](https:\/\/manual.cs50.io\/3\/newlocale) - create, modify, and free a locale object\n- [setlocale](https:\/\/manual.cs50.io\/3\/setlocale) - set the current locale\n- [uselocale](https:\/\/manual.cs50.io\/3\/uselocale) - set\/get the locale for the calling thread\n# [math.h](https:\/\/manual.cs50.io\/#math.h)\n- [acos](https:\/\/manual.cs50.io\/3\/acos) - arc cosine function\n- [acosf](https:\/\/manual.cs50.io\/3\/acosf) - arc cosine function\n- [acosh](https:\/\/manual.cs50.io\/3\/acosh) - inverse hyperbolic cosine function\n- [acoshf](https:\/\/manual.cs50.io\/3\/acoshf) - inverse hyperbolic cosine function\n- [acoshl](https:\/\/manual.cs50.io\/3\/acoshl) - inverse hyperbolic cosine function\n- [acosl](https:\/\/manual.cs50.io\/3\/acosl) - arc cosine function\n- [asin](https:\/\/manual.cs50.io\/3\/asin) - arc sine function\n- [asinf](https:\/\/manual.cs50.io\/3\/asinf) - arc sine function\n- [asinh](https:\/\/manual.cs50.io\/3\/asinh) - inverse hyperbolic sine function\n- [asinhf](https:\/\/manual.cs50.io\/3\/asinhf) - inverse hyperbolic sine function\n- [asinhl](https:\/\/manual.cs50.io\/3\/asinhl) - inverse hyperbolic sine function\n- [asinl](https:\/\/manual.cs50.io\/3\/asinl) - arc sine function\n- [atan](https:\/\/manual.cs50.io\/3\/atan) - arc tangent function\n- [atan2](https:\/\/manual.cs50.io\/3\/atan2) - arc tangent function of two variables\n- [atan2f](https:\/\/manual.cs50.io\/3\/atan2f) - arc tangent function of two variables\n- [atan2l](https:\/\/manual.cs50.io\/3\/atan2l) - arc tangent function of two variables\n- [atanf](https:\/\/manual.cs50.io\/3\/atanf) - arc tangent function\n- [atanh](https:\/\/manual.cs50.io\/3\/atanh) - inverse hyperbolic tangent function\n- [atanhf](https:\/\/manual.cs50.io\/3\/atanhf) - inverse hyperbolic tangent function\n- [atanhl](https:\/\/manual.cs50.io\/3\/atanhl) - inverse hyperbolic tangent function\n- [atanl](https:\/\/manual.cs50.io\/3\/atanl) - arc tangent function\n- [cbrt](https:\/\/manual.cs50.io\/3\/cbrt) - cube root function\n- [cbrtf](https:\/\/manual.cs50.io\/3\/cbrtf) - cube root function\n- [cbrtl](https:\/\/manual.cs50.io\/3\/cbrtl) - cube root function\n- [ceil](https:\/\/manual.cs50.io\/3\/ceil) - ceiling function: smallest integral value not less tha... calculate the ceiling of a number\n- [ceilf](https:\/\/manual.cs50.io\/3\/ceilf) - ceiling function: smallest integral value not less tha...\n- [ceill](https:\/\/manual.cs50.io\/3\/ceill) - ceiling function: smallest integral value not less tha...\n- [copysign](https:\/\/manual.cs50.io\/3\/copysign) - copy sign of a number\n- [copysignf](https:\/\/manual.cs50.io\/3\/copysignf) - copy sign of a number\n- [copysignl](https:\/\/manual.cs50.io\/3\/copysignl) - copy sign of a number\n- [cos](https:\/\/manual.cs50.io\/3\/cos) - cosine function\n- [cosf](https:\/\/manual.cs50.io\/3\/cosf) - cosine function\n- [cosh](https:\/\/manual.cs50.io\/3\/cosh) - hyperbolic cosine function\n- [coshf](https:\/\/manual.cs50.io\/3\/coshf) - hyperbolic cosine function\n- [coshl](https:\/\/manual.cs50.io\/3\/coshl) - hyperbolic cosine function\n- [cosl](https:\/\/manual.cs50.io\/3\/cosl) - cosine function\n- [drem](https:\/\/manual.cs50.io\/3\/drem) - floating-point remainder function\n- [dremf](https:\/\/manual.cs50.io\/3\/dremf) - floating-point remainder function\n- [dreml](https:\/\/manual.cs50.io\/3\/dreml) - floating-point remainder function\n- [erf](https:\/\/manual.cs50.io\/3\/erf) - error function\n- [erfc](https:\/\/manual.cs50.io\/3\/erfc) - complementary error function\n- [erfcf](https:\/\/manual.cs50.io\/3\/erfcf) - complementary error function\n- [erfcl](https:\/\/manual.cs50.io\/3\/erfcl) - complementary error function\n- [erff](https:\/\/manual.cs50.io\/3\/erff) - error function\n- [erfl](https:\/\/manual.cs50.io\/3\/erfl) - error function\n- [exp](https:\/\/manual.cs50.io\/3\/exp) - base-e exponential function\n- [exp10](https:\/\/manual.cs50.io\/3\/exp10) - base-10 exponential function\n- [exp10f](https:\/\/manual.cs50.io\/3\/exp10f) - base-10 exponential function\n- [exp10l](https:\/\/manual.cs50.io\/3\/exp10l) - base-10 exponential function\n- [exp2](https:\/\/manual.cs50.io\/3\/exp2) - base-2 exponential function\n- [exp2f](https:\/\/manual.cs50.io\/3\/exp2f) - base-2 exponential function\n- [exp2l](https:\/\/manual.cs50.io\/3\/exp2l) - base-2 exponential function\n- [expf](https:\/\/manual.cs50.io\/3\/expf) - base-e exponential function\n- [expl](https:\/\/manual.cs50.io\/3\/expl) - base-e exponential function\n- [expm1](https:\/\/manual.cs50.io\/3\/expm1) - exponential minus 1\n- [expm1f](https:\/\/manual.cs50.io\/3\/expm1f) - exponential minus 1\n- [expm1l](https:\/\/manual.cs50.io\/3\/expm1l) - exponential minus 1\n- [fabs](https:\/\/manual.cs50.io\/3\/fabs) - absolute value of floating-point number\n- [fabsf](https:\/\/manual.cs50.io\/3\/fabsf) - absolute value of floating-point number\n- [fabsl](https:\/\/manual.cs50.io\/3\/fabsl) - absolute value of floating-point number\n- [fdim](https:\/\/manual.cs50.io\/3\/fdim) - positive difference\n- [fdimf](https:\/\/manual.cs50.io\/3\/fdimf) - positive difference\n- [fdiml](https:\/\/manual.cs50.io\/3\/fdiml) - positive difference\n- [finite](https:\/\/manual.cs50.io\/3\/finite) - BSD floating-point classification functions\n- [finitef](https:\/\/manual.cs50.io\/3\/finitef) - BSD floating-point classification functions\n- [finitel](https:\/\/manual.cs50.io\/3\/finitel) - BSD floating-point classification functions\n- [floor](https:\/\/manual.cs50.io\/3\/floor) - largest integral value not greater than argument calculate the floor of a number\n- [floorf](https:\/\/manual.cs50.io\/3\/floorf) - largest integral value not greater than argument\n- [floorl](https:\/\/manual.cs50.io\/3\/floorl) - largest integral value not greater than argument\n- [fma](https:\/\/manual.cs50.io\/3\/fma) - floating-point multiply and add\n- [fmaf](https:\/\/manual.cs50.io\/3\/fmaf) - floating-point multiply and add\n- [fmal](https:\/\/manual.cs50.io\/3\/fmal) - floating-point multiply and add\n- [fmax](https:\/\/manual.cs50.io\/3\/fmax) - determine maximum of two floating-point numbers\n- [fmaxf](https:\/\/manual.cs50.io\/3\/fmaxf) - determine maximum of two floating-point numbers\n- [fmaxl](https:\/\/manual.cs50.io\/3\/fmaxl) - determine maximum of two floating-point numbers\n- [fmin](https:\/\/manual.cs50.io\/3\/fmin) - determine minimum of two floating-point numbers\n- [fminf](https:\/\/manual.cs50.io\/3\/fminf) - determine minimum of two floating-point numbers\n- [fminl](https:\/\/manual.cs50.io\/3\/fminl) - determine minimum of two floating-point numbers\n- [fmod](https:\/\/manual.cs50.io\/3\/fmod) - floating-point remainder function\n- [fmodf](https:\/\/manual.cs50.io\/3\/fmodf) - floating-point remainder function\n- [fmodl](https:\/\/manual.cs50.io\/3\/fmodl) - floating-point remainder function\n- [fpclassify](https:\/\/manual.cs50.io\/3\/fpclassify) - floating-point classification macros\n- [frexp](https:\/\/manual.cs50.io\/3\/frexp) - convert floating-point number to fractional and integr...\n- [frexpf](https:\/\/manual.cs50.io\/3\/frexpf) - convert floating-point number to fractional and integr...\n- [frexpl](https:\/\/manual.cs50.io\/3\/frexpl) - convert floating-point number to fractional and integr...\n- [gamma](https:\/\/manual.cs50.io\/3\/gamma) - (logarithm of the) gamma function\n- [gammaf](https:\/\/manual.cs50.io\/3\/gammaf) - (logarithm of the) gamma function\n- [gammal](https:\/\/manual.cs50.io\/3\/gammal) - (logarithm of the) gamma function\n- [HUGE\\_VAL](https:\/\/manual.cs50.io\/3\/HUGE_VAL) - floating-point constants\n- [HUGE\\_VALF](https:\/\/manual.cs50.io\/3\/HUGE_VALF) - floating-point constants\n- [HUGE\\_VALL](https:\/\/manual.cs50.io\/3\/HUGE_VALL) - floating-point constants\n- [hypot](https:\/\/manual.cs50.io\/3\/hypot) - Euclidean distance function\n- [hypotf](https:\/\/manual.cs50.io\/3\/hypotf) - Euclidean distance function\n- [hypotl](https:\/\/manual.cs50.io\/3\/hypotl) - Euclidean distance function\n- [ilogb](https:\/\/manual.cs50.io\/3\/ilogb) - get integer exponent of a floating-point value\n- [ilogbf](https:\/\/manual.cs50.io\/3\/ilogbf) - get integer exponent of a floating-point value\n- [ilogbl](https:\/\/manual.cs50.io\/3\/ilogbl) - get integer exponent of a floating-point value\n- [INFINITY](https:\/\/manual.cs50.io\/3\/INFINITY) - floating-point constants\n- [isfinite](https:\/\/manual.cs50.io\/3\/isfinite) - floating-point classification macros\n- [isgreater](https:\/\/manual.cs50.io\/3\/isgreater) - floating-point relational tests without exception for NaN\n- [isgreaterequal](https:\/\/manual.cs50.io\/3\/isgreaterequal) - floating-point relational tests without exception for NaN\n- [isinf](https:\/\/manual.cs50.io\/3\/isinf) - floating-point classification macros\n- [isinff](https:\/\/manual.cs50.io\/3\/isinff) - BSD floating-point classification functions\n- [isinfl](https:\/\/manual.cs50.io\/3\/isinfl) - BSD floating-point classification functions\n- [isless](https:\/\/manual.cs50.io\/3\/isless) - floating-point relational tests without exception for NaN\n- [islessequal](https:\/\/manual.cs50.io\/3\/islessequal) - floating-point relational tests without exception for NaN\n- [islessgreater](https:\/\/manual.cs50.io\/3\/islessgreater) - floating-point relational tests without exception for NaN\n- [isnan](https:\/\/manual.cs50.io\/3\/isnan) - floating-point classification macros\n- [isnanf](https:\/\/manual.cs50.io\/3\/isnanf) - BSD floating-point classification functions\n- [isnanl](https:\/\/manual.cs50.io\/3\/isnanl) - BSD floating-point classification functions\n- [isnormal](https:\/\/manual.cs50.io\/3\/isnormal) - floating-point classification macros\n- [isunordered](https:\/\/manual.cs50.io\/3\/isunordered) - floating-point relational tests without exception for NaN\n- [j0](https:\/\/manual.cs50.io\/3\/j0) - Bessel functions of the first kind\n- [j0f](https:\/\/manual.cs50.io\/3\/j0f) - Bessel functions of the first kind\n- [j0l](https:\/\/manual.cs50.io\/3\/j0l) - Bessel functions of the first kind\n- [j1](https:\/\/manual.cs50.io\/3\/j1) - Bessel functions of the first kind\n- [j1f](https:\/\/manual.cs50.io\/3\/j1f) - Bessel functions of the first kind\n- [j1l](https:\/\/manual.cs50.io\/3\/j1l) - Bessel functions of the first kind\n- [jn](https:\/\/manual.cs50.io\/3\/jn) - Bessel functions of the first kind\n- [jnf](https:\/\/manual.cs50.io\/3\/jnf) - Bessel functions of the first kind\n- [jnl](https:\/\/manual.cs50.io\/3\/jnl) - Bessel functions of the first kind\n- [ldexp](https:\/\/manual.cs50.io\/3\/ldexp) - multiply floating-point number by integral power of 2\n- [ldexpf](https:\/\/manual.cs50.io\/3\/ldexpf) - multiply floating-point number by integral power of 2\n- [ldexpl](https:\/\/manual.cs50.io\/3\/ldexpl) - multiply floating-point number by integral power of 2\n- [lgamma](https:\/\/manual.cs50.io\/3\/lgamma) - log gamma function\n- [lgamma\\_r](https:\/\/manual.cs50.io\/3\/lgamma_r) - log gamma function\n- [lgammaf](https:\/\/manual.cs50.io\/3\/lgammaf) - log gamma function\n- [lgammaf\\_r](https:\/\/manual.cs50.io\/3\/lgammaf_r) - log gamma function\n- [lgammal](https:\/\/manual.cs50.io\/3\/lgammal) - log gamma function\n- [lgammal\\_r](https:\/\/manual.cs50.io\/3\/lgammal_r) - log gamma function\n- [llrint](https:\/\/manual.cs50.io\/3\/llrint) - round to nearest integer\n- [llrintf](https:\/\/manual.cs50.io\/3\/llrintf) - round to nearest integer\n- [llrintl](https:\/\/manual.cs50.io\/3\/llrintl) - round to nearest integer\n- [llround](https:\/\/manual.cs50.io\/3\/llround) - round to nearest integer\n- [llroundf](https:\/\/manual.cs50.io\/3\/llroundf) - round to nearest integer\n- [llroundl](https:\/\/manual.cs50.io\/3\/llroundl) - round to nearest integer\n- [log](https:\/\/manual.cs50.io\/3\/log) - natural logarithmic function\n- [log10](https:\/\/manual.cs50.io\/3\/log10) - base-10 logarithmic function\n- [log10f](https:\/\/manual.cs50.io\/3\/log10f) - base-10 logarithmic function\n- [log10l](https:\/\/manual.cs50.io\/3\/log10l) - base-10 logarithmic function\n- [log1p](https:\/\/manual.cs50.io\/3\/log1p) - logarithm of 1 plus argument\n- [log1pf](https:\/\/manual.cs50.io\/3\/log1pf) - logarithm of 1 plus argument\n- [log1pl](https:\/\/manual.cs50.io\/3\/log1pl) - logarithm of 1 plus argument\n- [log2](https:\/\/manual.cs50.io\/3\/log2) - base-2 logarithmic function calculate the base-2 logarithm of a number\n- [log2f](https:\/\/manual.cs50.io\/3\/log2f) - base-2 logarithmic function\n- [log2l](https:\/\/manual.cs50.io\/3\/log2l) - base-2 logarithmic function\n- [logb](https:\/\/manual.cs50.io\/3\/logb) - get exponent of a floating-point value\n- [logbf](https:\/\/manual.cs50.io\/3\/logbf) - get exponent of a floating-point value\n- [logbl](https:\/\/manual.cs50.io\/3\/logbl) - get exponent of a floating-point value\n- [logf](https:\/\/manual.cs50.io\/3\/logf) - natural logarithmic function\n- [logl](https:\/\/manual.cs50.io\/3\/logl) - natural logarithmic function\n- [lrint](https:\/\/manual.cs50.io\/3\/lrint) - round to nearest integer\n- [lrintf](https:\/\/manual.cs50.io\/3\/lrintf) - round to nearest integer\n- [lrintl](https:\/\/manual.cs50.io\/3\/lrintl) - round to nearest integer\n- [lround](https:\/\/manual.cs50.io\/3\/lround) - round to nearest integer\n- [lroundf](https:\/\/manual.cs50.io\/3\/lroundf) - round to nearest integer\n- [lroundl](https:\/\/manual.cs50.io\/3\/lroundl) - round to nearest integer\n- [math\\_error](https:\/\/manual.cs50.io\/7\/math_error) - detecting errors from mathematical functions\n- [matherr](https:\/\/manual.cs50.io\/3\/matherr) - SVID math library exception handling\n- [modf](https:\/\/manual.cs50.io\/3\/modf) - extract signed integral and fractional values from flo...\n- [modff](https:\/\/manual.cs50.io\/3\/modff) - extract signed integral and fractional values from flo...\n- [modfl](https:\/\/manual.cs50.io\/3\/modfl) - extract signed integral and fractional values from flo...\n- [NAN](https:\/\/manual.cs50.io\/3\/NAN) - floating-point constants\n- [nan](https:\/\/manual.cs50.io\/3\/nan) - return 'Not a Number'\n- [nanf](https:\/\/manual.cs50.io\/3\/nanf) - return 'Not a Number'\n- [nanl](https:\/\/manual.cs50.io\/3\/nanl) - return 'Not a Number'\n- [nearbyint](https:\/\/manual.cs50.io\/3\/nearbyint) - round to nearest integer\n- [nearbyintf](https:\/\/manual.cs50.io\/3\/nearbyintf) - round to nearest integer\n- [nearbyintl](https:\/\/manual.cs50.io\/3\/nearbyintl) - round to nearest integer\n- [nextafter](https:\/\/manual.cs50.io\/3\/nextafter) - floating-point number manipulation\n- [nextafterf](https:\/\/manual.cs50.io\/3\/nextafterf) - floating-point number manipulation\n- [nextafterl](https:\/\/manual.cs50.io\/3\/nextafterl) - floating-point number manipulation\n- [nextdown](https:\/\/manual.cs50.io\/3\/nextdown) - return next floating-point number toward positive\/nega...\n- [nextdownf](https:\/\/manual.cs50.io\/3\/nextdownf) - return next floating-point number toward positive\/nega...\n- [nextdownl](https:\/\/manual.cs50.io\/3\/nextdownl) - return next floating-point number toward positive\/nega...\n- [nexttoward](https:\/\/manual.cs50.io\/3\/nexttoward) - floating-point number manipulation\n- [nexttowardf](https:\/\/manual.cs50.io\/3\/nexttowardf) - floating-point number manipulation\n- [nexttowardl](https:\/\/manual.cs50.io\/3\/nexttowardl) - floating-point number manipulation\n- [nextup](https:\/\/manual.cs50.io\/3\/nextup) - return next floating-point number toward positive\/nega...\n- [nextupf](https:\/\/manual.cs50.io\/3\/nextupf) - return next floating-point number toward positive\/nega...\n- [nextupl](https:\/\/manual.cs50.io\/3\/nextupl) - return next floating-point number toward positive\/nega...\n- [pow](https:\/\/manual.cs50.io\/3\/pow) - power functions raise a number to a power\n- [pow10](https:\/\/manual.cs50.io\/3\/pow10) - base-10 power functions\n- [pow10f](https:\/\/manual.cs50.io\/3\/pow10f) - base-10 power functions\n- [pow10l](https:\/\/manual.cs50.io\/3\/pow10l) - base-10 power functions\n- [powf](https:\/\/manual.cs50.io\/3\/powf) - power functions\n- [powl](https:\/\/manual.cs50.io\/3\/powl) - power functions\n- [remainder](https:\/\/manual.cs50.io\/3\/remainder) - floating-point remainder function\n- [remainderf](https:\/\/manual.cs50.io\/3\/remainderf) - floating-point remainder function\n- [remainderl](https:\/\/manual.cs50.io\/3\/remainderl) - floating-point remainder function\n- [remquo](https:\/\/manual.cs50.io\/3\/remquo) - remainder and part of quotient\n- [remquof](https:\/\/manual.cs50.io\/3\/remquof) - remainder and part of quotient\n- [remquol](https:\/\/manual.cs50.io\/3\/remquol) - remainder and part of quotient\n- [rint](https:\/\/manual.cs50.io\/3\/rint) - round to nearest integer\n- [rintf](https:\/\/manual.cs50.io\/3\/rintf) - round to nearest integer\n- [rintl](https:\/\/manual.cs50.io\/3\/rintl) - round to nearest integer\n- [round](https:\/\/manual.cs50.io\/3\/round) - round to nearest integer, away from zero round a number to the nearest integer\n- [roundf](https:\/\/manual.cs50.io\/3\/roundf) - round to nearest integer, away from zero\n- [roundl](https:\/\/manual.cs50.io\/3\/roundl) - round to nearest integer, away from zero\n- [scalb](https:\/\/manual.cs50.io\/3\/scalb) - multiply floating-point number by integral power of ra...\n- [scalbf](https:\/\/manual.cs50.io\/3\/scalbf) - multiply floating-point number by integral power of ra...\n- [scalbl](https:\/\/manual.cs50.io\/3\/scalbl) - multiply floating-point number by integral power of ra...\n- [scalbln](https:\/\/manual.cs50.io\/3\/scalbln) - multiply floating-point number by integral power of radix\n- [scalblnf](https:\/\/manual.cs50.io\/3\/scalblnf) - multiply floating-point number by integral power of radix\n- [scalblnl](https:\/\/manual.cs50.io\/3\/scalblnl) - multiply floating-point number by integral power of radix\n- [scalbn](https:\/\/manual.cs50.io\/3\/scalbn) - multiply floating-point number by integral power of radix\n- [scalbnf](https:\/\/manual.cs50.io\/3\/scalbnf) - multiply floating-point number by integral power of radix\n- [scalbnl](https:\/\/manual.cs50.io\/3\/scalbnl) - multiply floating-point number by integral power of radix\n- [signbit](https:\/\/manual.cs50.io\/3\/signbit) - test sign of a real floating-point number\n- [signgam](https:\/\/manual.cs50.io\/3\/signgam) - log gamma function\n- [significand](https:\/\/manual.cs50.io\/3\/significand) - get mantissa of floating-point number\n- [significandf](https:\/\/manual.cs50.io\/3\/significandf) - get mantissa of floating-point number\n- [significandl](https:\/\/manual.cs50.io\/3\/significandl) - get mantissa of floating-point number\n- [sin](https:\/\/manual.cs50.io\/3\/sin) - sine function\n- [sincos](https:\/\/manual.cs50.io\/3\/sincos) - calculate sin and cos simultaneously\n- [sincosf](https:\/\/manual.cs50.io\/3\/sincosf) - calculate sin and cos simultaneously\n- [sincosl](https:\/\/manual.cs50.io\/3\/sincosl) - calculate sin and cos simultaneously\n- [sinf](https:\/\/manual.cs50.io\/3\/sinf) - sine function\n- [sinh](https:\/\/manual.cs50.io\/3\/sinh) - hyperbolic sine function\n- [sinhf](https:\/\/manual.cs50.io\/3\/sinhf) - hyperbolic sine function\n- [sinhl](https:\/\/manual.cs50.io\/3\/sinhl) - hyperbolic sine function\n- [sinl](https:\/\/manual.cs50.io\/3\/sinl) - sine function\n- [sqrt](https:\/\/manual.cs50.io\/3\/sqrt) - square root function calculate the square root of a number\n- [sqrtf](https:\/\/manual.cs50.io\/3\/sqrtf) - square root function\n- [sqrtl](https:\/\/manual.cs50.io\/3\/sqrtl) - square root function\n- [tan](https:\/\/manual.cs50.io\/3\/tan) - tangent function\n- [tanf](https:\/\/manual.cs50.io\/3\/tanf) - tangent function\n- [tanh](https:\/\/manual.cs50.io\/3\/tanh) - hyperbolic tangent function\n- [tanhf](https:\/\/manual.cs50.io\/3\/tanhf) - hyperbolic tangent function\n- [tanhl](https:\/\/manual.cs50.io\/3\/tanhl) - hyperbolic tangent function\n- [tanl](https:\/\/manual.cs50.io\/3\/tanl) - tangent function\n- [tgamma](https:\/\/manual.cs50.io\/3\/tgamma) - true gamma function\n- [tgammaf](https:\/\/manual.cs50.io\/3\/tgammaf) - true gamma function\n- [tgammal](https:\/\/manual.cs50.io\/3\/tgammal) - true gamma function\n- [trunc](https:\/\/manual.cs50.io\/3\/trunc) - round to integer, toward zero\n- [truncf](https:\/\/manual.cs50.io\/3\/truncf) - round to integer, toward zero\n- [truncl](https:\/\/manual.cs50.io\/3\/truncl) - round to integer, toward zero\n- [y0](https:\/\/manual.cs50.io\/3\/y0) - Bessel functions of the second kind\n- [y0f](https:\/\/manual.cs50.io\/3\/y0f) - Bessel functions of the second kind\n- [y0l](https:\/\/manual.cs50.io\/3\/y0l) - Bessel functions of the second kind\n- [y1](https:\/\/manual.cs50.io\/3\/y1) - Bessel functions of the second kind\n- [y1f](https:\/\/manual.cs50.io\/3\/y1f) - Bessel functions of the second kind\n- [y1l](https:\/\/manual.cs50.io\/3\/y1l) - Bessel functions of the second kind\n- [yn](https:\/\/manual.cs50.io\/3\/yn) - Bessel functions of the second kind\n- [ynf](https:\/\/manual.cs50.io\/3\/ynf) - Bessel functions of the second kind\n- [ynl](https:\/\/manual.cs50.io\/3\/ynl) - Bessel functions of the second kind\n# [monetary.h](https:\/\/manual.cs50.io\/#monetary.h)\n- [strfmon](https:\/\/manual.cs50.io\/3\/strfmon) - convert monetary value to a string\n- [strfmon\\_l](https:\/\/manual.cs50.io\/3\/strfmon_l) - convert monetary value to a string\n# [mqueue.h](https:\/\/manual.cs50.io\/#mqueue.h)\n- [mq\\_close](https:\/\/manual.cs50.io\/3\/mq_close) - close a message queue descriptor\n- [mq\\_getattr](https:\/\/manual.cs50.io\/3\/mq_getattr) - get\/set message queue attributes\n- [mq\\_notify](https:\/\/manual.cs50.io\/2\/mq_notify) - register for notification when a message is available\n- [mq\\_notify](https:\/\/manual.cs50.io\/3\/mq_notify) - register for notification when a message is available\n- [mq\\_open](https:\/\/manual.cs50.io\/2\/mq_open) - open a message queue\n- [mq\\_open](https:\/\/manual.cs50.io\/3\/mq_open) - open a message queue\n- [mq\\_receive](https:\/\/manual.cs50.io\/3\/mq_receive) - receive a message from a message queue\n- [mq\\_send](https:\/\/manual.cs50.io\/3\/mq_send) - send a message to a message queue\n- [mq\\_setattr](https:\/\/manual.cs50.io\/3\/mq_setattr) - get\/set message queue attributes\n- [mq\\_timedreceive](https:\/\/manual.cs50.io\/2\/mq_timedreceive) - receive a message from a message queue\n- [mq\\_timedreceive](https:\/\/manual.cs50.io\/3\/mq_timedreceive) - receive a message from a message queue\n- [mq\\_timedsend](https:\/\/manual.cs50.io\/2\/mq_timedsend) - send a message to a message queue\n- [mq\\_timedsend](https:\/\/manual.cs50.io\/3\/mq_timedsend) - send a message to a message queue\n- [mq\\_unlink](https:\/\/manual.cs50.io\/2\/mq_unlink) - remove a message queue\n- [mq\\_unlink](https:\/\/manual.cs50.io\/3\/mq_unlink) - remove a message queue\n# [net\/if.h](https:\/\/manual.cs50.io\/#net\/if.h)\n- [if\\_freenameindex](https:\/\/manual.cs50.io\/3\/if_freenameindex) - get network interface names and indexes\n- [if\\_indextoname](https:\/\/manual.cs50.io\/3\/if_indextoname) - mappings between network interface names and indexes\n- [if\\_nameindex](https:\/\/manual.cs50.io\/3\/if_nameindex) - get network interface names and indexes\n- [if\\_nametoindex](https:\/\/manual.cs50.io\/3\/if_nametoindex) - mappings between network interface names and indexes\n# [netdb.h](https:\/\/manual.cs50.io\/#netdb.h)\n- [endhostent](https:\/\/manual.cs50.io\/3\/endhostent) - get network host entry\n- [endnetent](https:\/\/manual.cs50.io\/3\/endnetent) - get network entry\n- [endnetgrent](https:\/\/manual.cs50.io\/3\/endnetgrent) - handle network group entries\n- [endprotoent](https:\/\/manual.cs50.io\/3\/endprotoent) - get protocol entry\n- [endrpcent](https:\/\/manual.cs50.io\/3\/endrpcent) - get RPC entry\n- [endservent](https:\/\/manual.cs50.io\/3\/endservent) - get service entry\n- [gai\\_cancel](https:\/\/manual.cs50.io\/3\/gai_cancel) - asynchronous network address and service translation\n- [gai\\_error](https:\/\/manual.cs50.io\/3\/gai_error) - asynchronous network address and service translation\n- [gai\\_suspend](https:\/\/manual.cs50.io\/3\/gai_suspend) - asynchronous network address and service translation\n- [getaddrinfo\\_a](https:\/\/manual.cs50.io\/3\/getaddrinfo_a) - asynchronous network address and service translation\n- [gethostbyaddr](https:\/\/manual.cs50.io\/3\/gethostbyaddr) - get network host entry\n- [gethostbyaddr\\_r](https:\/\/manual.cs50.io\/3\/gethostbyaddr_r) - get network host entry\n- [gethostbyname](https:\/\/manual.cs50.io\/3\/gethostbyname) - get network host entry\n- [gethostbyname2](https:\/\/manual.cs50.io\/3\/gethostbyname2) - get network host entry\n- [gethostbyname2\\_r](https:\/\/manual.cs50.io\/3\/gethostbyname2_r) - get network host entry\n- [gethostbyname\\_r](https:\/\/manual.cs50.io\/3\/gethostbyname_r) - get network host entry\n- [gethostent](https:\/\/manual.cs50.io\/3\/gethostent) - get network host entry\n- [gethostent\\_r](https:\/\/manual.cs50.io\/3\/gethostent_r) - get network host entry\n- [getnetbyaddr](https:\/\/manual.cs50.io\/3\/getnetbyaddr) - get network entry\n- [getnetbyaddr\\_r](https:\/\/manual.cs50.io\/3\/getnetbyaddr_r) - get network entry (reentrant)\n- [getnetbyname](https:\/\/manual.cs50.io\/3\/getnetbyname) - get network entry\n- [getnetbyname\\_r](https:\/\/manual.cs50.io\/3\/getnetbyname_r) - get network entry (reentrant)\n- [getnetent](https:\/\/manual.cs50.io\/3\/getnetent) - get network entry\n- [getnetent\\_r](https:\/\/manual.cs50.io\/3\/getnetent_r) - get network entry (reentrant)\n- [getnetgrent](https:\/\/manual.cs50.io\/3\/getnetgrent) - handle network group entries\n- [getnetgrent\\_r](https:\/\/manual.cs50.io\/3\/getnetgrent_r) - handle network group entries\n- [getprotobyname](https:\/\/manual.cs50.io\/3\/getprotobyname) - get protocol entry\n- [getprotobyname\\_r](https:\/\/manual.cs50.io\/3\/getprotobyname_r) - get protocol entry (reentrant)\n- [getprotobynumber](https:\/\/manual.cs50.io\/3\/getprotobynumber) - get protocol entry\n- [getprotobynumber\\_r](https:\/\/manual.cs50.io\/3\/getprotobynumber_r) - get protocol entry (reentrant)\n- [getprotoent](https:\/\/manual.cs50.io\/3\/getprotoent) - get protocol entry\n- [getprotoent\\_r](https:\/\/manual.cs50.io\/3\/getprotoent_r) - get protocol entry (reentrant)\n- [getrpcbyname](https:\/\/manual.cs50.io\/3\/getrpcbyname) - get RPC entry\n- [getrpcbyname\\_r](https:\/\/manual.cs50.io\/3\/getrpcbyname_r) - get RPC entry (reentrant)\n- [getrpcbynumber](https:\/\/manual.cs50.io\/3\/getrpcbynumber) - get RPC entry\n- [getrpcbynumber\\_r](https:\/\/manual.cs50.io\/3\/getrpcbynumber_r) - get RPC entry (reentrant)\n- [getrpcent](https:\/\/manual.cs50.io\/3\/getrpcent) - get RPC entry\n- [getrpcent\\_r](https:\/\/manual.cs50.io\/3\/getrpcent_r) - get RPC entry (reentrant)\n- [getservbyname](https:\/\/manual.cs50.io\/3\/getservbyname) - get service entry\n- [getservbyname\\_r](https:\/\/manual.cs50.io\/3\/getservbyname_r) - get service entry (reentrant)\n- [getservbyport](https:\/\/manual.cs50.io\/3\/getservbyport) - get service entry\n- [getservbyport\\_r](https:\/\/manual.cs50.io\/3\/getservbyport_r) - get service entry (reentrant)\n- [getservent](https:\/\/manual.cs50.io\/3\/getservent) - get service entry\n- [getservent\\_r](https:\/\/manual.cs50.io\/3\/getservent_r) - get service entry (reentrant)\n- [h\\_errno](https:\/\/manual.cs50.io\/3\/h_errno) - get network host entry\n- [herror](https:\/\/manual.cs50.io\/3\/herror) - get network host entry\n- [hstrerror](https:\/\/manual.cs50.io\/3\/hstrerror) - get network host entry\n- [innetgr](https:\/\/manual.cs50.io\/3\/innetgr) - handle network group entries\n- [rexec](https:\/\/manual.cs50.io\/3\/rexec) - return stream to a remote command\n- [rexec\\_af](https:\/\/manual.cs50.io\/3\/rexec_af) - return stream to a remote command\n- [sethostent](https:\/\/manual.cs50.io\/3\/sethostent) - get network host entry\n- [setnetent](https:\/\/manual.cs50.io\/3\/setnetent) - get network entry\n- [setnetgrent](https:\/\/manual.cs50.io\/3\/setnetgrent) - handle network group entries\n- [setprotoent](https:\/\/manual.cs50.io\/3\/setprotoent) - get protocol entry\n- [setrpcent](https:\/\/manual.cs50.io\/3\/setrpcent) - get RPC entry\n- [setservent](https:\/\/manual.cs50.io\/3\/setservent) - get service entry\n# [netinet\/in.h](https:\/\/manual.cs50.io\/#netinet\/in.h)\n- [dn\\_comp](https:\/\/manual.cs50.io\/3\/dn_comp) - resolver routines\n- [dn\\_expand](https:\/\/manual.cs50.io\/3\/dn_expand) - resolver routines\n- [res\\_init](https:\/\/manual.cs50.io\/3\/res_init) - resolver routines\n- [res\\_mkquery](https:\/\/manual.cs50.io\/3\/res_mkquery) - resolver routines\n- [res\\_nclose](https:\/\/manual.cs50.io\/3\/res_nclose) - resolver routines\n- [res\\_ninit](https:\/\/manual.cs50.io\/3\/res_ninit) - resolver routines\n- [res\\_nmkquery](https:\/\/manual.cs50.io\/3\/res_nmkquery) - resolver routines\n- [res\\_nquery](https:\/\/manual.cs50.io\/3\/res_nquery) - resolver routines\n- [res\\_nquerydomain](https:\/\/manual.cs50.io\/3\/res_nquerydomain) - resolver routines\n- [res\\_nsearch](https:\/\/manual.cs50.io\/3\/res_nsearch) - resolver routines\n- [res\\_nsend](https:\/\/manual.cs50.io\/3\/res_nsend) - resolver routines\n- [res\\_query](https:\/\/manual.cs50.io\/3\/res_query) - resolver routines\n- [res\\_querydomain](https:\/\/manual.cs50.io\/3\/res_querydomain) - resolver routines\n- [res\\_search](https:\/\/manual.cs50.io\/3\/res_search) - resolver routines\n- [res\\_send](https:\/\/manual.cs50.io\/3\/res_send) - resolver routines\n- [resolver](https:\/\/manual.cs50.io\/3\/resolver) - resolver routines\n# [nl\\_types.h](https:\/\/manual.cs50.io\/#nl_types.h)\n- [catclose](https:\/\/manual.cs50.io\/3\/catclose) - open\/close a message catalog\n- [catgets](https:\/\/manual.cs50.io\/3\/catgets) - get message from a message catalog\n- [catopen](https:\/\/manual.cs50.io\/3\/catopen) - open\/close a message catalog\n# [poll.h](https:\/\/manual.cs50.io\/#poll.h)\n- [poll](https:\/\/manual.cs50.io\/2\/poll) - wait for some event on a file descriptor\n- [ppoll](https:\/\/manual.cs50.io\/2\/ppoll) - wait for some event on a file descriptor\n# [pthread.h](https:\/\/manual.cs50.io\/#pthread.h)\n- [pthread\\_attr\\_destroy](https:\/\/manual.cs50.io\/3\/pthread_attr_destroy) - initialize and destroy thread attributes object\n- [pthread\\_attr\\_getaffinity\\_np](https:\/\/manual.cs50.io\/3\/pthread_attr_getaffinity_np) - set\/get CPU affinity attribute in thread at...\n- [pthread\\_attr\\_getdetachstate](https:\/\/manual.cs50.io\/3\/pthread_attr_getdetachstate) - set\/get detach state attribute in thread at...\n- [pthread\\_attr\\_getguardsize](https:\/\/manual.cs50.io\/3\/pthread_attr_getguardsize) - set\/get guard size attribute in thread attrib...\n- [pthread\\_attr\\_getinheritsched](https:\/\/manual.cs50.io\/3\/pthread_attr_getinheritsched) - set\/get inherit-scheduler attribute in thr...\n- [pthread\\_attr\\_getschedparam](https:\/\/manual.cs50.io\/3\/pthread_attr_getschedparam) - set\/get scheduling parameter attributes in t...\n- [pthread\\_attr\\_getschedpolicy](https:\/\/manual.cs50.io\/3\/pthread_attr_getschedpolicy) - set\/get scheduling policy attribute in thre...\n- [pthread\\_attr\\_getscope](https:\/\/manual.cs50.io\/3\/pthread_attr_getscope) - set\/get contention scope attribute in thread attr...\n- [pthread\\_attr\\_getsigmask\\_np](https:\/\/manual.cs50.io\/3\/pthread_attr_getsigmask_np) - set\/get signal mask attribute in thread attr...\n- [pthread\\_attr\\_getstack](https:\/\/manual.cs50.io\/3\/pthread_attr_getstack) - set\/get stack attributes in thread attributes object\n- [pthread\\_attr\\_getstackaddr](https:\/\/manual.cs50.io\/3\/pthread_attr_getstackaddr) - set\/get stack address attribute in thread att...\n- [pthread\\_attr\\_getstacksize](https:\/\/manual.cs50.io\/3\/pthread_attr_getstacksize) - set\/get stack size attribute in thread attrib...\n- [pthread\\_attr\\_init](https:\/\/manual.cs50.io\/3\/pthread_attr_init) - initialize and destroy thread attributes object\n- [pthread\\_attr\\_setaffinity\\_np](https:\/\/manual.cs50.io\/3\/pthread_attr_setaffinity_np) - set\/get CPU affinity attribute in thread at...\n- [pthread\\_attr\\_setdetachstate](https:\/\/manual.cs50.io\/3\/pthread_attr_setdetachstate) - set\/get detach state attribute in thread at...\n- [pthread\\_attr\\_setguardsize](https:\/\/manual.cs50.io\/3\/pthread_attr_setguardsize) - set\/get guard size attribute in thread attrib...\n- [pthread\\_attr\\_setinheritsched](https:\/\/manual.cs50.io\/3\/pthread_attr_setinheritsched) - set\/get inherit-scheduler attribute in thr...\n- [pthread\\_attr\\_setschedparam](https:\/\/manual.cs50.io\/3\/pthread_attr_setschedparam) - set\/get scheduling parameter attributes in t...\n- [pthread\\_attr\\_setschedpolicy](https:\/\/manual.cs50.io\/3\/pthread_attr_setschedpolicy) - set\/get scheduling policy attribute in thre...\n- [pthread\\_attr\\_setscope](https:\/\/manual.cs50.io\/3\/pthread_attr_setscope) - set\/get contention scope attribute in thread attr...\n- [pthread\\_attr\\_setsigmask\\_np](https:\/\/manual.cs50.io\/3\/pthread_attr_setsigmask_np) - set\/get signal mask attribute in thread attr...\n- [pthread\\_attr\\_setstack](https:\/\/manual.cs50.io\/3\/pthread_attr_setstack) - set\/get stack attributes in thread attributes object\n- [pthread\\_attr\\_setstackaddr](https:\/\/manual.cs50.io\/3\/pthread_attr_setstackaddr) - set\/get stack address attribute in thread att...\n- [pthread\\_attr\\_setstacksize](https:\/\/manual.cs50.io\/3\/pthread_attr_setstacksize) - set\/get stack size attribute in thread attrib...\n- [pthread\\_cancel](https:\/\/manual.cs50.io\/3\/pthread_cancel) - send a cancelation request to a thread\n- [pthread\\_cleanup\\_pop](https:\/\/manual.cs50.io\/3\/pthread_cleanup_pop) - push and pop thread cancelation clean-up handlers\n- [pthread\\_cleanup\\_pop\\_restore\\_np](https:\/\/manual.cs50.io\/3\/pthread_cleanup_pop_restore_np) - push and pop thread cancelation clean-up...\n- [pthread\\_cleanup\\_push](https:\/\/manual.cs50.io\/3\/pthread_cleanup_push) - push and pop thread cancelation clean-up handlers\n- [pthread\\_cleanup\\_push\\_defer\\_np](https:\/\/manual.cs50.io\/3\/pthread_cleanup_push_defer_np) - push and pop thread cancelation clean-up ...\n- [pthread\\_create](https:\/\/manual.cs50.io\/3\/pthread_create) - create a new thread\n- [pthread\\_detach](https:\/\/manual.cs50.io\/3\/pthread_detach) - detach a thread\n- [pthread\\_equal](https:\/\/manual.cs50.io\/3\/pthread_equal) - compare thread IDs\n- [pthread\\_exit](https:\/\/manual.cs50.io\/3\/pthread_exit) - terminate calling thread\n- [pthread\\_getaffinity\\_np](https:\/\/manual.cs50.io\/3\/pthread_getaffinity_np) - set\/get CPU affinity of a thread\n- [pthread\\_getattr\\_default\\_np](https:\/\/manual.cs50.io\/3\/pthread_getattr_default_np) - get or set default thread-creation attributes\n- [pthread\\_getattr\\_np](https:\/\/manual.cs50.io\/3\/pthread_getattr_np) - get attributes of created thread\n- [pthread\\_getconcurrency](https:\/\/manual.cs50.io\/3\/pthread_getconcurrency) - set\/get the concurrency level\n- [pthread\\_getcpuclockid](https:\/\/manual.cs50.io\/3\/pthread_getcpuclockid) - retrieve ID of a thread's CPU time clock\n- [pthread\\_getname\\_np](https:\/\/manual.cs50.io\/3\/pthread_getname_np) - set\/get the name of a thread\n- [pthread\\_getschedparam](https:\/\/manual.cs50.io\/3\/pthread_getschedparam) - set\/get scheduling policy and parameters of a thread\n- [pthread\\_join](https:\/\/manual.cs50.io\/3\/pthread_join) - join with a terminated thread\n- [pthread\\_kill\\_other\\_threads\\_np](https:\/\/manual.cs50.io\/3\/pthread_kill_other_threads_np) - terminate all other threads in process\n- [pthread\\_mutex\\_consistent](https:\/\/manual.cs50.io\/3\/pthread_mutex_consistent) - make a robust mutex consistent\n- [pthread\\_mutex\\_consistent\\_np](https:\/\/manual.cs50.io\/3\/pthread_mutex_consistent_np) - make a robust mutex consistent\n- [pthread\\_mutexattr\\_getpshared](https:\/\/manual.cs50.io\/3\/pthread_mutexattr_getpshared) - get\/set process-shared mutex attribute\n- [pthread\\_mutexattr\\_getrobust](https:\/\/manual.cs50.io\/3\/pthread_mutexattr_getrobust) - get and set the robustness attribute of a m...\n- [pthread\\_mutexattr\\_getrobust\\_np](https:\/\/manual.cs50.io\/3\/pthread_mutexattr_getrobust_np) - get and set the robustness attribute of ...\n- [pthread\\_mutexattr\\_setpshared](https:\/\/manual.cs50.io\/3\/pthread_mutexattr_setpshared) - get\/set process-shared mutex attribute\n- [pthread\\_mutexattr\\_setrobust](https:\/\/manual.cs50.io\/3\/pthread_mutexattr_setrobust) - get and set the robustness attribute of a m...\n- [pthread\\_mutexattr\\_setrobust\\_np](https:\/\/manual.cs50.io\/3\/pthread_mutexattr_setrobust_np) - get and set the robustness attribute of ...\n- [pthread\\_rwlockattr\\_getkind\\_np](https:\/\/manual.cs50.io\/3\/pthread_rwlockattr_getkind_np) - set\/get the read-write lock kind of the t...\n- [pthread\\_rwlockattr\\_setkind\\_np](https:\/\/manual.cs50.io\/3\/pthread_rwlockattr_setkind_np) - set\/get the read-write lock kind of the t...\n- [pthread\\_self](https:\/\/manual.cs50.io\/3\/pthread_self) - obtain ID of the calling thread\n- [pthread\\_setaffinity\\_np](https:\/\/manual.cs50.io\/3\/pthread_setaffinity_np) - set\/get CPU affinity of a thread\n- [pthread\\_setattr\\_default\\_np](https:\/\/manual.cs50.io\/3\/pthread_setattr_default_np) - get or set default thread-creation attributes\n- [pthread\\_setcancelstate](https:\/\/manual.cs50.io\/3\/pthread_setcancelstate) - set cancelability state and type\n- [pthread\\_setcanceltype](https:\/\/manual.cs50.io\/3\/pthread_setcanceltype) - set cancelability state and type\n- [pthread\\_setconcurrency](https:\/\/manual.cs50.io\/3\/pthread_setconcurrency) - set\/get the concurrency level\n- [pthread\\_setname\\_np](https:\/\/manual.cs50.io\/3\/pthread_setname_np) - set\/get the name of a thread\n- [pthread\\_setschedparam](https:\/\/manual.cs50.io\/3\/pthread_setschedparam) - set\/get scheduling policy and parameters of a thread\n- [pthread\\_setschedprio](https:\/\/manual.cs50.io\/3\/pthread_setschedprio) - set scheduling priority of a thread\n- [pthread\\_spin\\_destroy](https:\/\/manual.cs50.io\/3\/pthread_spin_destroy) - initialize or destroy a spin lock\n- [pthread\\_spin\\_init](https:\/\/manual.cs50.io\/3\/pthread_spin_init) - initialize or destroy a spin lock\n- [pthread\\_spin\\_lock](https:\/\/manual.cs50.io\/3\/pthread_spin_lock) - lock and unlock a spin lock\n- [pthread\\_spin\\_trylock](https:\/\/manual.cs50.io\/3\/pthread_spin_trylock) - lock and unlock a spin lock\n- [pthread\\_spin\\_unlock](https:\/\/manual.cs50.io\/3\/pthread_spin_unlock) - lock and unlock a spin lock\n- [pthread\\_testcancel](https:\/\/manual.cs50.io\/3\/pthread_testcancel) - request delivery of any pending cancelation request\n- [pthread\\_timedjoin\\_np](https:\/\/manual.cs50.io\/3\/pthread_timedjoin_np) - try to join with a terminated thread\n- [pthread\\_tryjoin\\_np](https:\/\/manual.cs50.io\/3\/pthread_tryjoin_np) - try to join with a terminated thread\n- [pthread\\_yield](https:\/\/manual.cs50.io\/3\/pthread_yield) - yield the processor\n# [pwd.h](https:\/\/manual.cs50.io\/#pwd.h)\n- [fgetpwent\\_r](https:\/\/manual.cs50.io\/3\/fgetpwent_r) - get passwd file entry reentrantly\n- [getpwent\\_r](https:\/\/manual.cs50.io\/3\/getpwent_r) - get passwd file entry reentrantly\n# [regex.h](https:\/\/manual.cs50.io\/#regex.h)\n- [regcomp](https:\/\/manual.cs50.io\/3\/regcomp) - POSIX regex functions\n- [regerror](https:\/\/manual.cs50.io\/3\/regerror) - POSIX regex functions\n- [regex](https:\/\/manual.cs50.io\/3\/regex) - POSIX regex functions\n- [regexec](https:\/\/manual.cs50.io\/3\/regexec) - POSIX regex functions\n- [regfree](https:\/\/manual.cs50.io\/3\/regfree) - POSIX regex functions\n# [sched.h](https:\/\/manual.cs50.io\/#sched.h)\n- [\\_\\_clone2](https:\/\/manual.cs50.io\/2\/__clone2) - create a child process\n- [clone](https:\/\/manual.cs50.io\/2\/clone) - create a child process\n- [clone2](https:\/\/manual.cs50.io\/2\/clone2) - create a child process\n- [clone3](https:\/\/manual.cs50.io\/2\/clone3) - create a child process\n- [CPU\\_ALLOC](https:\/\/manual.cs50.io\/3\/CPU_ALLOC) - macros for manipulating CPU sets\n- [CPU\\_ALLOC\\_SIZE](https:\/\/manual.cs50.io\/3\/CPU_ALLOC_SIZE) - macros for manipulating CPU sets\n- [CPU\\_AND](https:\/\/manual.cs50.io\/3\/CPU_AND) - macros for manipulating CPU sets\n- [CPU\\_AND\\_S](https:\/\/manual.cs50.io\/3\/CPU_AND_S) - macros for manipulating CPU sets\n- [CPU\\_CLR](https:\/\/manual.cs50.io\/3\/CPU_CLR) - macros for manipulating CPU sets\n- [CPU\\_CLR\\_S](https:\/\/manual.cs50.io\/3\/CPU_CLR_S) - macros for manipulating CPU sets\n- [CPU\\_COUNT](https:\/\/manual.cs50.io\/3\/CPU_COUNT) - macros for manipulating CPU sets\n- [CPU\\_COUNT\\_S](https:\/\/manual.cs50.io\/3\/CPU_COUNT_S) - macros for manipulating CPU sets\n- [CPU\\_EQUAL](https:\/\/manual.cs50.io\/3\/CPU_EQUAL) - macros for manipulating CPU sets\n- [CPU\\_EQUAL\\_S](https:\/\/manual.cs50.io\/3\/CPU_EQUAL_S) - macros for manipulating CPU sets\n- [CPU\\_FREE](https:\/\/manual.cs50.io\/3\/CPU_FREE) - macros for manipulating CPU sets\n- [CPU\\_ISSET](https:\/\/manual.cs50.io\/3\/CPU_ISSET) - macros for manipulating CPU sets\n- [CPU\\_ISSET\\_S](https:\/\/manual.cs50.io\/3\/CPU_ISSET_S) - macros for manipulating CPU sets\n- [CPU\\_OR](https:\/\/manual.cs50.io\/3\/CPU_OR) - macros for manipulating CPU sets\n- [CPU\\_OR\\_S](https:\/\/manual.cs50.io\/3\/CPU_OR_S) - macros for manipulating CPU sets\n- [CPU\\_SET](https:\/\/manual.cs50.io\/3\/CPU_SET) - macros for manipulating CPU sets\n- [CPU\\_SET\\_S](https:\/\/manual.cs50.io\/3\/CPU_SET_S) - macros for manipulating CPU sets\n- [CPU\\_XOR](https:\/\/manual.cs50.io\/3\/CPU_XOR) - macros for manipulating CPU sets\n- [CPU\\_XOR\\_S](https:\/\/manual.cs50.io\/3\/CPU_XOR_S) - macros for manipulating CPU sets\n- [CPU\\_ZERO](https:\/\/manual.cs50.io\/3\/CPU_ZERO) - macros for manipulating CPU sets\n- [CPU\\_ZERO\\_S](https:\/\/manual.cs50.io\/3\/CPU_ZERO_S) - macros for manipulating CPU sets\n- [getcpu](https:\/\/manual.cs50.io\/2\/getcpu) - determine CPU and NUMA node on which the calling threa...\n- [sched\\_get\\_priority\\_max](https:\/\/manual.cs50.io\/2\/sched_get_priority_max) - get static priority range\n- [sched\\_get\\_priority\\_min](https:\/\/manual.cs50.io\/2\/sched_get_priority_min) - get static priority range\n- [sched\\_getaffinity](https:\/\/manual.cs50.io\/2\/sched_getaffinity) - set and get a thread's CPU affinity mask\n- [sched\\_getcpu](https:\/\/manual.cs50.io\/3\/sched_getcpu) - determine CPU on which the calling thread is running\n- [sched\\_getparam](https:\/\/manual.cs50.io\/2\/sched_getparam) - set and get scheduling parameters\n- [sched\\_getscheduler](https:\/\/manual.cs50.io\/2\/sched_getscheduler) - set and get scheduling policy\/parameters\n- [sched\\_rr\\_get\\_interval](https:\/\/manual.cs50.io\/2\/sched_rr_get_interval) - get the SCHED\\_RR interval for the named process\n- [sched\\_setaffinity](https:\/\/manual.cs50.io\/2\/sched_setaffinity) - set and get a thread's CPU affinity mask\n- [sched\\_setparam](https:\/\/manual.cs50.io\/2\/sched_setparam) - set and get scheduling parameters\n- [sched\\_setscheduler](https:\/\/manual.cs50.io\/2\/sched_setscheduler) - set and get scheduling policy\/parameters\n- [sched\\_yield](https:\/\/manual.cs50.io\/2\/sched_yield) - yield the processor\n- [setns](https:\/\/manual.cs50.io\/2\/setns) - reassociate thread with a namespace\n- [unshare](https:\/\/manual.cs50.io\/2\/unshare) - disassociate parts of the process execution context\n# [search.h](https:\/\/manual.cs50.io\/#search.h)\n- [hcreate](https:\/\/manual.cs50.io\/3\/hcreate) - hash table management\n- [hcreate\\_r](https:\/\/manual.cs50.io\/3\/hcreate_r) - hash table management\n- [hdestroy](https:\/\/manual.cs50.io\/3\/hdestroy) - hash table management\n- [hdestroy\\_r](https:\/\/manual.cs50.io\/3\/hdestroy_r) - hash table management\n- [hsearch](https:\/\/manual.cs50.io\/3\/hsearch) - hash table management\n- [hsearch\\_r](https:\/\/manual.cs50.io\/3\/hsearch_r) - hash table management\n- [insque](https:\/\/manual.cs50.io\/3\/insque) - insert\/remove an item from a queue\n- [lfind](https:\/\/manual.cs50.io\/3\/lfind) - linear search of an array\n- [lsearch](https:\/\/manual.cs50.io\/3\/lsearch) - linear search of an array\n- [remque](https:\/\/manual.cs50.io\/3\/remque) - insert\/remove an item from a queue\n- [tdelete](https:\/\/manual.cs50.io\/3\/tdelete) - manage a binary search tree\n- [tdestroy](https:\/\/manual.cs50.io\/3\/tdestroy) - manage a binary search tree\n- [tfind](https:\/\/manual.cs50.io\/3\/tfind) - manage a binary search tree\n- [tsearch](https:\/\/manual.cs50.io\/3\/tsearch) - manage a binary search tree\n- [twalk](https:\/\/manual.cs50.io\/3\/twalk) - manage a binary search tree\n- [twalk\\_r](https:\/\/manual.cs50.io\/3\/twalk_r) - manage a binary search tree\n# [semaphore.h](https:\/\/manual.cs50.io\/#semaphore.h)\n- [sem\\_close](https:\/\/manual.cs50.io\/3\/sem_close) - close a named semaphore\n- [sem\\_destroy](https:\/\/manual.cs50.io\/3\/sem_destroy) - destroy an unnamed semaphore\n- [sem\\_getvalue](https:\/\/manual.cs50.io\/3\/sem_getvalue) - get the value of a semaphore\n- [sem\\_init](https:\/\/manual.cs50.io\/3\/sem_init) - initialize an unnamed semaphore\n- [sem\\_open](https:\/\/manual.cs50.io\/3\/sem_open) - initialize and open a named semaphore\n- [sem\\_post](https:\/\/manual.cs50.io\/3\/sem_post) - unlock a semaphore\n- [sem\\_timedwait](https:\/\/manual.cs50.io\/3\/sem_timedwait) - lock a semaphore\n- [sem\\_trywait](https:\/\/manual.cs50.io\/3\/sem_trywait) - lock a semaphore\n- [sem\\_unlink](https:\/\/manual.cs50.io\/3\/sem_unlink) - remove a named semaphore\n- [sem\\_wait](https:\/\/manual.cs50.io\/3\/sem_wait) - lock a semaphore\n# [setjmp.h](https:\/\/manual.cs50.io\/#setjmp.h)\n- [longjmp](https:\/\/manual.cs50.io\/3\/longjmp) - performing a nonlocal goto\n- [setjmp](https:\/\/manual.cs50.io\/3\/setjmp) - performing a nonlocal goto\n- [siglongjmp](https:\/\/manual.cs50.io\/3\/siglongjmp) - performing a nonlocal goto\n- [sigsetjmp](https:\/\/manual.cs50.io\/3\/sigsetjmp) - performing a nonlocal goto\n# [signal.h](https:\/\/manual.cs50.io\/#signal.h)\n- [bsd\\_signal](https:\/\/manual.cs50.io\/3\/bsd_signal) - signal handling with BSD semantics\n- [gsignal](https:\/\/manual.cs50.io\/3\/gsignal) - software signal facility\n- [kill](https:\/\/manual.cs50.io\/2\/kill) - send signal to a process\n- [killpg](https:\/\/manual.cs50.io\/3\/killpg) - send signal to a process group\n- [psiginfo](https:\/\/manual.cs50.io\/3\/psiginfo) - print signal description\n- [psignal](https:\/\/manual.cs50.io\/3\/psignal) - print signal description\n- [pthread\\_kill](https:\/\/manual.cs50.io\/3\/pthread_kill) - send a signal to a thread\n- [pthread\\_sigmask](https:\/\/manual.cs50.io\/3\/pthread_sigmask) - examine and change mask of blocked signals\n- [pthread\\_sigqueue](https:\/\/manual.cs50.io\/3\/pthread_sigqueue) - queue a signal and data to a thread\n- [raise](https:\/\/manual.cs50.io\/3\/raise) - send a signal to the caller\n- [rt\\_sigaction](https:\/\/manual.cs50.io\/2\/rt_sigaction) - examine and change a signal action\n- [rt\\_sigpending](https:\/\/manual.cs50.io\/2\/rt_sigpending) - examine pending signals\n- [rt\\_sigprocmask](https:\/\/manual.cs50.io\/2\/rt_sigprocmask) - examine and change blocked signals\n- [rt\\_sigsuspend](https:\/\/manual.cs50.io\/2\/rt_sigsuspend) - wait for a signal\n- [rt\\_sigtimedwait](https:\/\/manual.cs50.io\/2\/rt_sigtimedwait) - synchronously wait for queued signals\n- [sigaction](https:\/\/manual.cs50.io\/2\/sigaction) - examine and change a signal action\n- [sigaddset](https:\/\/manual.cs50.io\/3\/sigaddset) - POSIX signal set operations\n- [sigaltstack](https:\/\/manual.cs50.io\/2\/sigaltstack) - set and\/or get signal stack context\n- [sigandset](https:\/\/manual.cs50.io\/3\/sigandset) - POSIX signal set operations\n- [sigblock](https:\/\/manual.cs50.io\/3\/sigblock) - BSD signal API\n- [sigdelset](https:\/\/manual.cs50.io\/3\/sigdelset) - POSIX signal set operations\n- [sigemptyset](https:\/\/manual.cs50.io\/3\/sigemptyset) - POSIX signal set operations\n- [sigfillset](https:\/\/manual.cs50.io\/3\/sigfillset) - POSIX signal set operations\n- [siggetmask](https:\/\/manual.cs50.io\/3\/siggetmask) - BSD signal API\n- [sighold](https:\/\/manual.cs50.io\/3\/sighold) - System V signal API\n- [sigignore](https:\/\/manual.cs50.io\/3\/sigignore) - System V signal API\n- [siginterrupt](https:\/\/manual.cs50.io\/3\/siginterrupt) - allow signals to interrupt system calls\n- [sigisemptyset](https:\/\/manual.cs50.io\/3\/sigisemptyset) - POSIX signal set operations\n- [sigismember](https:\/\/manual.cs50.io\/3\/sigismember) - POSIX signal set operations\n- [sigmask](https:\/\/manual.cs50.io\/3\/sigmask) - BSD signal API\n- [signal](https:\/\/manual.cs50.io\/2\/signal) - ANSI C signal handling\n- [sigorset](https:\/\/manual.cs50.io\/3\/sigorset) - POSIX signal set operations\n- [sigpause](https:\/\/manual.cs50.io\/3\/sigpause) - atomically release blocked signals and wait for interrupt\n- [sigpending](https:\/\/manual.cs50.io\/2\/sigpending) - examine pending signals\n- [sigprocmask](https:\/\/manual.cs50.io\/2\/sigprocmask) - examine and change blocked signals\n- [sigqueue](https:\/\/manual.cs50.io\/3\/sigqueue) - queue a signal and data to a process\n- [sigrelse](https:\/\/manual.cs50.io\/3\/sigrelse) - System V signal API\n- [sigset](https:\/\/manual.cs50.io\/3\/sigset) - System V signal API\n- [sigsetmask](https:\/\/manual.cs50.io\/3\/sigsetmask) - BSD signal API\n- [sigsetops](https:\/\/manual.cs50.io\/3\/sigsetops) - POSIX signal set operations\n- [sigstack](https:\/\/manual.cs50.io\/3\/sigstack) - set and\/or get signal stack context\n- [sigsuspend](https:\/\/manual.cs50.io\/2\/sigsuspend) - wait for a signal\n- [sigtimedwait](https:\/\/manual.cs50.io\/2\/sigtimedwait) - synchronously wait for queued signals\n- [sigvec](https:\/\/manual.cs50.io\/3\/sigvec) - BSD signal API\n- [sigwait](https:\/\/manual.cs50.io\/3\/sigwait) - wait for a signal\n- [sigwaitinfo](https:\/\/manual.cs50.io\/2\/sigwaitinfo) - synchronously wait for queued signals\n- [ssignal](https:\/\/manual.cs50.io\/3\/ssignal) - software signal facility\n- [sysv\\_signal](https:\/\/manual.cs50.io\/3\/sysv_signal) - signal handling with System V semantics\n# [spawn.h](https:\/\/manual.cs50.io\/#spawn.h)\n- [posix\\_spawn](https:\/\/manual.cs50.io\/3\/posix_spawn) - spawn a process\n- [posix\\_spawnp](https:\/\/manual.cs50.io\/3\/posix_spawnp) - spawn a process\n# [stdarg.h](https:\/\/manual.cs50.io\/#stdarg.h)\n- [stdarg](https:\/\/manual.cs50.io\/3\/stdarg) - variable argument lists\n- [va\\_arg](https:\/\/manual.cs50.io\/3\/va_arg) - variable argument lists\n- [va\\_copy](https:\/\/manual.cs50.io\/3\/va_copy) - variable argument lists\n- [va\\_end](https:\/\/manual.cs50.io\/3\/va_end) - variable argument lists\n- [va\\_start](https:\/\/manual.cs50.io\/3\/va_start) - variable argument lists\n# [stddef.h](https:\/\/manual.cs50.io\/#stddef.h)\n- [offsetof](https:\/\/manual.cs50.io\/3\/offsetof) - offset of a structure member\n- [wcstoimax](https:\/\/manual.cs50.io\/3\/wcstoimax) - convert wide-character string to integer\n- [wcstoumax](https:\/\/manual.cs50.io\/3\/wcstoumax) - convert wide-character string to integer\n# [stdio.h](https:\/\/manual.cs50.io\/#stdio.h)\n- [\\_\\_fbufsize](https:\/\/manual.cs50.io\/3\/__fbufsize) - interfaces to stdio FILE structure\n- [\\_\\_flbf](https:\/\/manual.cs50.io\/3\/__flbf) - interfaces to stdio FILE structure\n- [\\_\\_fpending](https:\/\/manual.cs50.io\/3\/__fpending) - interfaces to stdio FILE structure\n- [\\_\\_fpurge](https:\/\/manual.cs50.io\/3\/__fpurge) - purge a stream\n- [\\_\\_freadable](https:\/\/manual.cs50.io\/3\/__freadable) - interfaces to stdio FILE structure\n- [\\_\\_freading](https:\/\/manual.cs50.io\/3\/__freading) - interfaces to stdio FILE structure\n- [\\_\\_fsetlocking](https:\/\/manual.cs50.io\/3\/__fsetlocking) - interfaces to stdio FILE structure\n- [\\_\\_fwritable](https:\/\/manual.cs50.io\/3\/__fwritable) - interfaces to stdio FILE structure\n- [\\_\\_fwriting](https:\/\/manual.cs50.io\/3\/__fwriting) - interfaces to stdio FILE structure\n- [\\_flushlbf](https:\/\/manual.cs50.io\/3\/_flushlbf) - interfaces to stdio FILE structure\n- [addmntent](https:\/\/manual.cs50.io\/3\/addmntent) - get filesystem descriptor file entry\n- [asprintf](https:\/\/manual.cs50.io\/3\/asprintf) - print to allocated string\n- [clearerr](https:\/\/manual.cs50.io\/3\/clearerr) - check and reset stream status\n- [clearerr\\_unlocked](https:\/\/manual.cs50.io\/3\/clearerr_unlocked) - nonlocking stdio functions\n- [ctermid](https:\/\/manual.cs50.io\/3\/ctermid) - get controlling terminal name\n- [dprintf](https:\/\/manual.cs50.io\/3\/dprintf) - formatted output conversion\n- [endmntent](https:\/\/manual.cs50.io\/3\/endmntent) - get filesystem descriptor file entry\n- [fclose](https:\/\/manual.cs50.io\/3\/fclose) - close a stream close a file\n- [fcloseall](https:\/\/manual.cs50.io\/3\/fcloseall) - close all open streams\n- [fdopen](https:\/\/manual.cs50.io\/3\/fdopen) - stream open functions\n- [feof](https:\/\/manual.cs50.io\/3\/feof) - check and reset stream status\n- [feof\\_unlocked](https:\/\/manual.cs50.io\/3\/feof_unlocked) - nonlocking stdio functions\n- [ferror](https:\/\/manual.cs50.io\/3\/ferror) - check and reset stream status\n- [ferror\\_unlocked](https:\/\/manual.cs50.io\/3\/ferror_unlocked) - nonlocking stdio functions\n- [fflush](https:\/\/manual.cs50.io\/3\/fflush) - flush a stream\n- [fflush\\_unlocked](https:\/\/manual.cs50.io\/3\/fflush_unlocked) - nonlocking stdio functions\n- [fgetc](https:\/\/manual.cs50.io\/3\/fgetc) - input of characters and strings\n- [fgetc\\_unlocked](https:\/\/manual.cs50.io\/3\/fgetc_unlocked) - nonlocking stdio functions\n- [fgetgrent](https:\/\/manual.cs50.io\/3\/fgetgrent) - get group file entry\n- [fgetpos](https:\/\/manual.cs50.io\/3\/fgetpos) - reposition a stream\n- [fgetpwent](https:\/\/manual.cs50.io\/3\/fgetpwent) - get password file entry\n- [fgets](https:\/\/manual.cs50.io\/3\/fgets) - input of characters and strings\n- [fgets\\_unlocked](https:\/\/manual.cs50.io\/3\/fgets_unlocked) - nonlocking stdio functions\n- [fgetwc](https:\/\/manual.cs50.io\/3\/fgetwc) - read a wide character from a FILE stream\n- [fgetwc\\_unlocked](https:\/\/manual.cs50.io\/3\/fgetwc_unlocked) - nonlocking stdio functions\n- [fgetws\\_unlocked](https:\/\/manual.cs50.io\/3\/fgetws_unlocked) - nonlocking stdio functions\n- [fileno](https:\/\/manual.cs50.io\/3\/fileno) - obtain file descriptor of a stdio stream\n- [fileno\\_unlocked](https:\/\/manual.cs50.io\/3\/fileno_unlocked) - nonlocking stdio functions\n- [flockfile](https:\/\/manual.cs50.io\/3\/flockfile) - lock FILE for stdio\n- [fmemopen](https:\/\/manual.cs50.io\/3\/fmemopen) - open memory as stream\n- [fopen](https:\/\/manual.cs50.io\/3\/fopen) - stream open functions open a file\n- [fopencookie](https:\/\/manual.cs50.io\/3\/fopencookie) - open a custom stream\n- [fprintf](https:\/\/manual.cs50.io\/3\/fprintf) - formatted output conversion print to a file\n- [fpurge](https:\/\/manual.cs50.io\/3\/fpurge) - purge a stream\n- [fputc](https:\/\/manual.cs50.io\/3\/fputc) - output of characters and strings\n- [fputc\\_unlocked](https:\/\/manual.cs50.io\/3\/fputc_unlocked) - nonlocking stdio functions\n- [fputs](https:\/\/manual.cs50.io\/3\/fputs) - output of characters and strings\n- [fputs\\_unlocked](https:\/\/manual.cs50.io\/3\/fputs_unlocked) - nonlocking stdio functions\n- [fputwc](https:\/\/manual.cs50.io\/3\/fputwc) - write a wide character to a FILE stream\n- [fputwc\\_unlocked](https:\/\/manual.cs50.io\/3\/fputwc_unlocked) - nonlocking stdio functions\n- [fputws\\_unlocked](https:\/\/manual.cs50.io\/3\/fputws_unlocked) - nonlocking stdio functions\n- [fread](https:\/\/manual.cs50.io\/3\/fread) - binary stream input\/output read bytes from a file\n- [fread\\_unlocked](https:\/\/manual.cs50.io\/3\/fread_unlocked) - nonlocking stdio functions\n- [freopen](https:\/\/manual.cs50.io\/3\/freopen) - stream open functions\n- [fscanf](https:\/\/manual.cs50.io\/3\/fscanf) - input FILE format conversion get input from a file\n- [fseek](https:\/\/manual.cs50.io\/3\/fseek) - reposition a stream\n- [fseeko](https:\/\/manual.cs50.io\/3\/fseeko) - seek to or report file position\n- [fsetpos](https:\/\/manual.cs50.io\/3\/fsetpos) - reposition a stream\n- [ftell](https:\/\/manual.cs50.io\/3\/ftell) - reposition a stream\n- [ftello](https:\/\/manual.cs50.io\/3\/ftello) - seek to or report file position\n- [ftrylockfile](https:\/\/manual.cs50.io\/3\/ftrylockfile) - lock FILE for stdio\n- [funlockfile](https:\/\/manual.cs50.io\/3\/funlockfile) - lock FILE for stdio\n- [fwprintf](https:\/\/manual.cs50.io\/3\/fwprintf) - formatted wide-character output conversion\n- [fwrite](https:\/\/manual.cs50.io\/3\/fwrite) - binary stream input\/output write bytes to a file\n- [fwrite\\_unlocked](https:\/\/manual.cs50.io\/3\/fwrite_unlocked) - nonlocking stdio functions\n- [getc](https:\/\/manual.cs50.io\/3\/getc) - input of characters and strings\n- [getc\\_unlocked](https:\/\/manual.cs50.io\/3\/getc_unlocked) - nonlocking stdio functions\n- [getchar](https:\/\/manual.cs50.io\/3\/getchar) - input of characters and strings\n- [getchar\\_unlocked](https:\/\/manual.cs50.io\/3\/getchar_unlocked) - nonlocking stdio functions\n- [getdelim](https:\/\/manual.cs50.io\/3\/getdelim) - delimited string input\n- [getline](https:\/\/manual.cs50.io\/3\/getline) - delimited string input\n- [getmntent](https:\/\/manual.cs50.io\/3\/getmntent) - get filesystem descriptor file entry\n- [getmntent\\_r](https:\/\/manual.cs50.io\/3\/getmntent_r) - get filesystem descriptor file entry\n- [gets](https:\/\/manual.cs50.io\/3\/gets) - get a string from standard input (DEPRECATED)\n- [getw](https:\/\/manual.cs50.io\/3\/getw) - input and output of words (ints)\n- [getwc](https:\/\/manual.cs50.io\/3\/getwc) - read a wide character from a FILE stream\n- [getwc\\_unlocked](https:\/\/manual.cs50.io\/3\/getwc_unlocked) - nonlocking stdio functions\n- [getwchar\\_unlocked](https:\/\/manual.cs50.io\/3\/getwchar_unlocked) - nonlocking stdio functions\n- [hasmntopt](https:\/\/manual.cs50.io\/3\/hasmntopt) - get filesystem descriptor file entry\n- [open\\_memstream](https:\/\/manual.cs50.io\/3\/open_memstream) - open a dynamic memory buffer stream\n- [open\\_wmemstream](https:\/\/manual.cs50.io\/3\/open_wmemstream) - open a dynamic memory buffer stream\n- [pclose](https:\/\/manual.cs50.io\/3\/pclose) - pipe stream to or from a process\n- [perror](https:\/\/manual.cs50.io\/3\/perror) - print a system error message\n- [popen](https:\/\/manual.cs50.io\/3\/popen) - pipe stream to or from a process\n- [printf](https:\/\/manual.cs50.io\/3\/printf) - formatted output conversion print to the screen\n- [putc](https:\/\/manual.cs50.io\/3\/putc) - output of characters and strings\n- [putc\\_unlocked](https:\/\/manual.cs50.io\/3\/putc_unlocked) - nonlocking stdio functions\n- [putchar](https:\/\/manual.cs50.io\/3\/putchar) - output of characters and strings\n- [putchar\\_unlocked](https:\/\/manual.cs50.io\/3\/putchar_unlocked) - nonlocking stdio functions\n- [putpwent](https:\/\/manual.cs50.io\/3\/putpwent) - write a password file entry\n- [puts](https:\/\/manual.cs50.io\/3\/puts) - output of characters and strings\n- [putw](https:\/\/manual.cs50.io\/3\/putw) - input and output of words (ints)\n- [putwc](https:\/\/manual.cs50.io\/3\/putwc) - write a wide character to a FILE stream\n- [putwc\\_unlocked](https:\/\/manual.cs50.io\/3\/putwc_unlocked) - nonlocking stdio functions\n- [putwchar\\_unlocked](https:\/\/manual.cs50.io\/3\/putwchar_unlocked) - nonlocking stdio functions\n- [remove](https:\/\/manual.cs50.io\/3\/remove) - remove a file or directory\n- [rename](https:\/\/manual.cs50.io\/2\/rename) - change the name or location of a file\n- [renameat](https:\/\/manual.cs50.io\/2\/renameat) - change the name or location of a file\n- [renameat2](https:\/\/manual.cs50.io\/2\/renameat2) - change the name or location of a file\n- [rewind](https:\/\/manual.cs50.io\/3\/rewind) - reposition a stream\n- [scanf](https:\/\/manual.cs50.io\/3\/scanf) - input FILE format conversion get input from a user\n- [setbuf](https:\/\/manual.cs50.io\/3\/setbuf) - stream buffering operations\n- [setbuffer](https:\/\/manual.cs50.io\/3\/setbuffer) - stream buffering operations\n- [setlinebuf](https:\/\/manual.cs50.io\/3\/setlinebuf) - stream buffering operations\n- [setmntent](https:\/\/manual.cs50.io\/3\/setmntent) - get filesystem descriptor file entry\n- [setvbuf](https:\/\/manual.cs50.io\/3\/setvbuf) - stream buffering operations\n- [snprintf](https:\/\/manual.cs50.io\/3\/snprintf) - formatted output conversion\n- [sprintf](https:\/\/manual.cs50.io\/3\/sprintf) - formatted output conversion print to a string\n- [sscanf](https:\/\/manual.cs50.io\/3\/sscanf) - input string format conversion\n- [stderr](https:\/\/manual.cs50.io\/3\/stderr) - standard I\/O streams\n- [stdin](https:\/\/manual.cs50.io\/3\/stdin) - standard I\/O streams\n- [stdio](https:\/\/manual.cs50.io\/3\/stdio) - standard input\/output library functions\n- [stdio\\_ext](https:\/\/manual.cs50.io\/3\/stdio_ext) - interfaces to stdio FILE structure\n- [stdout](https:\/\/manual.cs50.io\/3\/stdout) - standard I\/O streams\n- [swprintf](https:\/\/manual.cs50.io\/3\/swprintf) - formatted wide-character output conversion\n- [sys\\_errlist](https:\/\/manual.cs50.io\/3\/sys_errlist) - print a system error message\n- [sys\\_nerr](https:\/\/manual.cs50.io\/3\/sys_nerr) - print a system error message\n- [tempnam](https:\/\/manual.cs50.io\/3\/tempnam) - create a name for a temporary file\n- [tmpfile](https:\/\/manual.cs50.io\/3\/tmpfile) - create a temporary file\n- [tmpnam](https:\/\/manual.cs50.io\/3\/tmpnam) - create a name for a temporary file\n- [tmpnam\\_r](https:\/\/manual.cs50.io\/3\/tmpnam_r) - create a name for a temporary file\n- [ungetc](https:\/\/manual.cs50.io\/3\/ungetc) - input of characters and strings\n- [unlocked\\_stdio](https:\/\/manual.cs50.io\/3\/unlocked_stdio) - nonlocking stdio functions\n- [vasprintf](https:\/\/manual.cs50.io\/3\/vasprintf) - print to allocated string\n- [vdprintf](https:\/\/manual.cs50.io\/3\/vdprintf) - formatted output conversion\n- [vfprintf](https:\/\/manual.cs50.io\/3\/vfprintf) - formatted output conversion\n- [vfscanf](https:\/\/manual.cs50.io\/3\/vfscanf) - input FILE format conversion\n- [vfwprintf](https:\/\/manual.cs50.io\/3\/vfwprintf) - formatted wide-character output conversion\n- [vprintf](https:\/\/manual.cs50.io\/3\/vprintf) - formatted output conversion\n- [vscanf](https:\/\/manual.cs50.io\/3\/vscanf) - input FILE format conversion\n- [vsnprintf](https:\/\/manual.cs50.io\/3\/vsnprintf) - formatted output conversion\n- [vsprintf](https:\/\/manual.cs50.io\/3\/vsprintf) - formatted output conversion\n- [vsscanf](https:\/\/manual.cs50.io\/3\/vsscanf) - input string format conversion\n- [vswprintf](https:\/\/manual.cs50.io\/3\/vswprintf) - formatted wide-character output conversion\n- [vwprintf](https:\/\/manual.cs50.io\/3\/vwprintf) - formatted wide-character output conversion\n- [wprintf](https:\/\/manual.cs50.io\/3\/wprintf) - formatted wide-character output conversion\n# [stdlib.h](https:\/\/manual.cs50.io\/#stdlib.h)\n- [a64l](https:\/\/manual.cs50.io\/3\/a64l) - convert between long and base-64\n- [abort](https:\/\/manual.cs50.io\/3\/abort) - cause abnormal process termination\n- [abs](https:\/\/manual.cs50.io\/3\/abs) - compute the absolute value of an integer\n- [aligned\\_alloc](https:\/\/manual.cs50.io\/3\/aligned_alloc) - allocate aligned memory\n- [arc4random](https:\/\/manual.cs50.io\/3\/arc4random) - cryptographically-secure pseudorandom number generator\n- [arc4random\\_buf](https:\/\/manual.cs50.io\/3\/arc4random_buf) - cryptographically-secure pseudorandom number generator\n- [arc4random\\_uniform](https:\/\/manual.cs50.io\/3\/arc4random_uniform) - cryptographically-secure pseudorandom number generator\n- [atexit](https:\/\/manual.cs50.io\/3\/atexit) - register a function to be called at normal process ter...\n- [atof](https:\/\/manual.cs50.io\/3\/atof) - convert a string to a double convert a `string` to a `float`\n- [atoi](https:\/\/manual.cs50.io\/3\/atoi) - convert a string to an integer convert a `string` to an `int`\n- [atol](https:\/\/manual.cs50.io\/3\/atol) - convert a string to an integer convert a `string` to a `long`\n- [atoll](https:\/\/manual.cs50.io\/3\/atoll) - convert a string to an integer\n- [atoq](https:\/\/manual.cs50.io\/3\/atoq) - convert a string to an integer\n- [bsearch](https:\/\/manual.cs50.io\/3\/bsearch) - binary search of a sorted array\n- [calloc](https:\/\/manual.cs50.io\/3\/calloc) - allocate and free dynamic memory\n- [canonicalize\\_file\\_name](https:\/\/manual.cs50.io\/3\/canonicalize_file_name) - return the canonicalized absolute pathname\n- [cfree](https:\/\/manual.cs50.io\/3\/cfree) - free allocated memory\n- [clearenv](https:\/\/manual.cs50.io\/3\/clearenv) - clear the environment\n- [div](https:\/\/manual.cs50.io\/3\/div) - compute quotient and remainder of an integer division\n- [drand48](https:\/\/manual.cs50.io\/3\/drand48) - generate uniformly distributed pseudo-random numbers\n- [drand48\\_r](https:\/\/manual.cs50.io\/3\/drand48_r) - generate uniformly distributed pseudo-random numbers r...\n- [ecvt](https:\/\/manual.cs50.io\/3\/ecvt) - convert a floating-point number to a string\n- [ecvt\\_r](https:\/\/manual.cs50.io\/3\/ecvt_r) - convert a floating-point number to a string\n- [erand48](https:\/\/manual.cs50.io\/3\/erand48) - generate uniformly distributed pseudo-random numbers\n- [erand48\\_r](https:\/\/manual.cs50.io\/3\/erand48_r) - generate uniformly distributed pseudo-random numbers r...\n- [exit](https:\/\/manual.cs50.io\/3\/exit) - cause normal process termination\n- [fcvt](https:\/\/manual.cs50.io\/3\/fcvt) - convert a floating-point number to a string\n- [fcvt\\_r](https:\/\/manual.cs50.io\/3\/fcvt_r) - convert a floating-point number to a string\n- [free](https:\/\/manual.cs50.io\/3\/free) - allocate and free dynamic memory free dynamically allocated memory\n- [gcvt](https:\/\/manual.cs50.io\/3\/gcvt) - convert a floating-point number to a string\n- [getenv](https:\/\/manual.cs50.io\/3\/getenv) - get an environment variable\n- [getloadavg](https:\/\/manual.cs50.io\/3\/getloadavg) - get system load averages\n- [getpt](https:\/\/manual.cs50.io\/3\/getpt) - open a new pseudoterminal master\n- [getsubopt](https:\/\/manual.cs50.io\/3\/getsubopt) - parse suboption arguments from a string\n- [grantpt](https:\/\/manual.cs50.io\/3\/grantpt) - grant access to the slave pseudoterminal\n- [imaxabs](https:\/\/manual.cs50.io\/3\/imaxabs) - compute the absolute value of an integer\n- [imaxdiv](https:\/\/manual.cs50.io\/3\/imaxdiv) - compute quotient and remainder of an integer division\n- [initstate](https:\/\/manual.cs50.io\/3\/initstate) - random number generator\n- [initstate\\_r](https:\/\/manual.cs50.io\/3\/initstate_r) - reentrant random number generator\n- [jrand48](https:\/\/manual.cs50.io\/3\/jrand48) - generate uniformly distributed pseudo-random numbers\n- [jrand48\\_r](https:\/\/manual.cs50.io\/3\/jrand48_r) - generate uniformly distributed pseudo-random numbers r...\n- [l64a](https:\/\/manual.cs50.io\/3\/l64a) - convert between long and base-64\n- [labs](https:\/\/manual.cs50.io\/3\/labs) - compute the absolute value of an integer\n- [lcong48](https:\/\/manual.cs50.io\/3\/lcong48) - generate uniformly distributed pseudo-random numbers\n- [lcong48\\_r](https:\/\/manual.cs50.io\/3\/lcong48_r) - generate uniformly distributed pseudo-random numbers r...\n- [ldiv](https:\/\/manual.cs50.io\/3\/ldiv) - compute quotient and remainder of an integer division\n- [llabs](https:\/\/manual.cs50.io\/3\/llabs) - compute the absolute value of an integer\n- [lldiv](https:\/\/manual.cs50.io\/3\/lldiv) - compute quotient and remainder of an integer division\n- [lrand48](https:\/\/manual.cs50.io\/3\/lrand48) - generate uniformly distributed pseudo-random numbers\n- [lrand48\\_r](https:\/\/manual.cs50.io\/3\/lrand48_r) - generate uniformly distributed pseudo-random numbers r...\n- [malloc](https:\/\/manual.cs50.io\/3\/malloc) - allocate and free dynamic memory allocate memory dynamically\n- [MB\\_CUR\\_MAX](https:\/\/manual.cs50.io\/3\/MB_CUR_MAX) - maximum length of a multibyte character in the current...\n- [mblen](https:\/\/manual.cs50.io\/3\/mblen) - determine number of bytes in next multibyte character\n- [mbstowcs](https:\/\/manual.cs50.io\/3\/mbstowcs) - convert a multibyte string to a wide-character string\n- [mbtowc](https:\/\/manual.cs50.io\/3\/mbtowc) - convert a multibyte sequence to a wide character\n- [memalign](https:\/\/manual.cs50.io\/3\/memalign) - allocate aligned memory\n- [mkdtemp](https:\/\/manual.cs50.io\/3\/mkdtemp) - create a unique temporary directory\n- [mkostemp](https:\/\/manual.cs50.io\/3\/mkostemp) - create a unique temporary file\n- [mkostemps](https:\/\/manual.cs50.io\/3\/mkostemps) - create a unique temporary file\n- [mkstemp](https:\/\/manual.cs50.io\/3\/mkstemp) - create a unique temporary file\n- [mkstemps](https:\/\/manual.cs50.io\/3\/mkstemps) - create a unique temporary file\n- [mktemp](https:\/\/manual.cs50.io\/3\/mktemp) - make a unique temporary filename\n- [mrand48](https:\/\/manual.cs50.io\/3\/mrand48) - generate uniformly distributed pseudo-random numbers\n- [mrand48\\_r](https:\/\/manual.cs50.io\/3\/mrand48_r) - generate uniformly distributed pseudo-random numbers r...\n- [nrand48](https:\/\/manual.cs50.io\/3\/nrand48) - generate uniformly distributed pseudo-random numbers\n- [nrand48\\_r](https:\/\/manual.cs50.io\/3\/nrand48_r) - generate uniformly distributed pseudo-random numbers r...\n- [on\\_exit](https:\/\/manual.cs50.io\/3\/on_exit) - register a function to be called at normal process ter...\n- [posix\\_memalign](https:\/\/manual.cs50.io\/3\/posix_memalign) - allocate aligned memory\n- [posix\\_openpt](https:\/\/manual.cs50.io\/3\/posix_openpt) - open a pseudoterminal device\n- [ptsname](https:\/\/manual.cs50.io\/3\/ptsname) - get the name of the slave pseudoterminal\n- [ptsname\\_r](https:\/\/manual.cs50.io\/3\/ptsname_r) - get the name of the slave pseudoterminal\n- [putenv](https:\/\/manual.cs50.io\/3\/putenv) - change or add an environment variable\n- [pvalloc](https:\/\/manual.cs50.io\/3\/pvalloc) - allocate aligned memory\n- [qecvt](https:\/\/manual.cs50.io\/3\/qecvt) - convert a floating-point number to a string\n- [qecvt\\_r](https:\/\/manual.cs50.io\/3\/qecvt_r) - convert a floating-point number to a string\n- [qfcvt](https:\/\/manual.cs50.io\/3\/qfcvt) - convert a floating-point number to a string\n- [qfcvt\\_r](https:\/\/manual.cs50.io\/3\/qfcvt_r) - convert a floating-point number to a string\n- [qgcvt](https:\/\/manual.cs50.io\/3\/qgcvt) - convert a floating-point number to a string\n- [qsort](https:\/\/manual.cs50.io\/3\/qsort) - sort an array\n- [qsort\\_r](https:\/\/manual.cs50.io\/3\/qsort_r) - sort an array\n- [rand](https:\/\/manual.cs50.io\/3\/rand) - pseudo-random number generator\n- [rand\\_r](https:\/\/manual.cs50.io\/3\/rand_r) - pseudo-random number generator\n- [random](https:\/\/manual.cs50.io\/3\/random) - random number generator generate a pseudorandom number\n- [random\\_r](https:\/\/manual.cs50.io\/3\/random_r) - reentrant random number generator\n- [realloc](https:\/\/manual.cs50.io\/3\/realloc) - allocate and free dynamic memory reallocate memory dynamically\n- [reallocarray](https:\/\/manual.cs50.io\/3\/reallocarray) - allocate and free dynamic memory\n- [rpmatch](https:\/\/manual.cs50.io\/3\/rpmatch) - determine if the answer to a question is affirmative o...\n- [secure\\_getenv](https:\/\/manual.cs50.io\/3\/secure_getenv) - get an environment variable\n- [seed48](https:\/\/manual.cs50.io\/3\/seed48) - generate uniformly distributed pseudo-random numbers\n- [seed48\\_r](https:\/\/manual.cs50.io\/3\/seed48_r) - generate uniformly distributed pseudo-random numbers r...\n- [setenv](https:\/\/manual.cs50.io\/3\/setenv) - change or add an environment variable\n- [setstate](https:\/\/manual.cs50.io\/3\/setstate) - random number generator\n- [setstate\\_r](https:\/\/manual.cs50.io\/3\/setstate_r) - reentrant random number generator\n- [srand](https:\/\/manual.cs50.io\/3\/srand) - pseudo-random number generator\n- [srand48](https:\/\/manual.cs50.io\/3\/srand48) - generate uniformly distributed pseudo-random numbers\n- [srand48\\_r](https:\/\/manual.cs50.io\/3\/srand48_r) - generate uniformly distributed pseudo-random numbers r...\n- [srandom](https:\/\/manual.cs50.io\/3\/srandom) - random number generator seed pseudorandom number generation\n- [srandom\\_r](https:\/\/manual.cs50.io\/3\/srandom_r) - reentrant random number generator\n- [strfromd](https:\/\/manual.cs50.io\/3\/strfromd) - convert a floating-point value into a string\n- [strfromf](https:\/\/manual.cs50.io\/3\/strfromf) - convert a floating-point value into a string\n- [strfroml](https:\/\/manual.cs50.io\/3\/strfroml) - convert a floating-point value into a string\n- [strtod](https:\/\/manual.cs50.io\/3\/strtod) - convert ASCII string to floating-point number\n- [strtof](https:\/\/manual.cs50.io\/3\/strtof) - convert ASCII string to floating-point number\n- [strtol](https:\/\/manual.cs50.io\/3\/strtol) - convert a string to a long integer\n- [strtold](https:\/\/manual.cs50.io\/3\/strtold) - convert ASCII string to floating-point number\n- [strtoll](https:\/\/manual.cs50.io\/3\/strtoll) - convert a string to a long integer\n- [strtoq](https:\/\/manual.cs50.io\/3\/strtoq) - convert a string to a long integer\n- [strtoul](https:\/\/manual.cs50.io\/3\/strtoul) - convert a string to an unsigned long integer\n- [strtoull](https:\/\/manual.cs50.io\/3\/strtoull) - convert a string to an unsigned long integer\n- [strtouq](https:\/\/manual.cs50.io\/3\/strtouq) - convert a string to an unsigned long integer\n- [system](https:\/\/manual.cs50.io\/3\/system) - execute a shell command\n- [unlockpt](https:\/\/manual.cs50.io\/3\/unlockpt) - unlock a pseudoterminal master\/slave pair\n- [unsetenv](https:\/\/manual.cs50.io\/3\/unsetenv) - change or add an environment variable\n- [valloc](https:\/\/manual.cs50.io\/3\/valloc) - allocate aligned memory\n- [wcstombs](https:\/\/manual.cs50.io\/3\/wcstombs) - convert a wide-character string to a multibyte string\n- [wctomb](https:\/\/manual.cs50.io\/3\/wctomb) - convert a wide character to a multibyte sequence\n# [string.h](https:\/\/manual.cs50.io\/#string.h)\n- [bstring](https:\/\/manual.cs50.io\/3\/bstring) - byte string operations\n- [memccpy](https:\/\/manual.cs50.io\/3\/memccpy) - copy memory area\n- [memchr](https:\/\/manual.cs50.io\/3\/memchr) - scan memory for a character\n- [memcmp](https:\/\/manual.cs50.io\/3\/memcmp) - compare memory areas\n- [memcpy](https:\/\/manual.cs50.io\/3\/memcpy) - copy memory area\n- [memfrob](https:\/\/manual.cs50.io\/3\/memfrob) - frobnicate (obfuscate) a memory area\n- [memmem](https:\/\/manual.cs50.io\/3\/memmem) - locate a substring\n- [memmove](https:\/\/manual.cs50.io\/3\/memmove) - copy memory area\n- [mempcpy](https:\/\/manual.cs50.io\/3\/mempcpy) - copy memory area\n- [memrchr](https:\/\/manual.cs50.io\/3\/memrchr) - scan memory for a character\n- [memset](https:\/\/manual.cs50.io\/3\/memset) - fill memory with a constant byte\n- [rawmemchr](https:\/\/manual.cs50.io\/3\/rawmemchr) - scan memory for a character\n- [sigabbrev\\_np](https:\/\/manual.cs50.io\/3\/sigabbrev_np) - return string describing signal\n- [sigdescr\\_np](https:\/\/manual.cs50.io\/3\/sigdescr_np) - return string describing signal\n- [stpcpy](https:\/\/manual.cs50.io\/3\/stpcpy) - copy or catenate a string\n- [stpncpy](https:\/\/manual.cs50.io\/3\/stpncpy) - fill a fixed-size buffer with non-null bytes from a st...\n- [strcasestr](https:\/\/manual.cs50.io\/3\/strcasestr) - locate a substring locate a substring\n- [strcat](https:\/\/manual.cs50.io\/3\/strcat) - copy or catenate a string\n- [strchr](https:\/\/manual.cs50.io\/3\/strchr) - locate character in string\n- [strchrnul](https:\/\/manual.cs50.io\/3\/strchrnul) - locate character in string\n- [strcmp](https:\/\/manual.cs50.io\/3\/strcmp) - compare two strings compare two strings\n- [strcoll](https:\/\/manual.cs50.io\/3\/strcoll) - compare two strings using the current locale\n- [strcpy](https:\/\/manual.cs50.io\/3\/strcpy) - copy or catenate a string copy a string\n- [strcspn](https:\/\/manual.cs50.io\/3\/strcspn) - get length of a prefix substring\n- [strdup](https:\/\/manual.cs50.io\/3\/strdup) - duplicate a string\n- [strdupa](https:\/\/manual.cs50.io\/3\/strdupa) - duplicate a string\n- [strerror](https:\/\/manual.cs50.io\/3\/strerror) - return string describing error number\n- [strerror\\_l](https:\/\/manual.cs50.io\/3\/strerror_l) - return string describing error number\n- [strerror\\_r](https:\/\/manual.cs50.io\/3\/strerror_r) - return string describing error number\n- [strerrordesc\\_np](https:\/\/manual.cs50.io\/3\/strerrordesc_np) - return string describing error number\n- [strerrorname\\_np](https:\/\/manual.cs50.io\/3\/strerrorname_np) - return string describing error number\n- [strfry](https:\/\/manual.cs50.io\/3\/strfry) - randomize a string\n- [strlen](https:\/\/manual.cs50.io\/3\/strlen) - calculate the length of a string calculate the length of a string\n- [strncat](https:\/\/manual.cs50.io\/3\/strncat) - append non-null bytes from a source array to a string,...\n- [strncmp](https:\/\/manual.cs50.io\/3\/strncmp) - compare two strings\n- [strncpy](https:\/\/manual.cs50.io\/3\/strncpy) - fill a fixed-size buffer with non-null bytes from a st...\n- [strndup](https:\/\/manual.cs50.io\/3\/strndup) - duplicate a string\n- [strndupa](https:\/\/manual.cs50.io\/3\/strndupa) - duplicate a string\n- [strnlen](https:\/\/manual.cs50.io\/3\/strnlen) - determine the length of a fixed-size string\n- [strpbrk](https:\/\/manual.cs50.io\/3\/strpbrk) - search a string for any of a set of bytes\n- [strrchr](https:\/\/manual.cs50.io\/3\/strrchr) - locate character in string\n- [strsep](https:\/\/manual.cs50.io\/3\/strsep) - extract token from string\n- [strsignal](https:\/\/manual.cs50.io\/3\/strsignal) - return string describing signal\n- [strspn](https:\/\/manual.cs50.io\/3\/strspn) - get length of a prefix substring\n- [strstr](https:\/\/manual.cs50.io\/3\/strstr) - locate a substring locate a substring\n- [strtok](https:\/\/manual.cs50.io\/3\/strtok) - extract tokens from strings\n- [strtok\\_r](https:\/\/manual.cs50.io\/3\/strtok_r) - extract tokens from strings\n- [strverscmp](https:\/\/manual.cs50.io\/3\/strverscmp) - compare two version strings\n- [strxfrm](https:\/\/manual.cs50.io\/3\/strxfrm) - string transformation\n- [sys\\_siglist](https:\/\/manual.cs50.io\/3\/sys_siglist) - return string describing signal\n- [wmempcpy](https:\/\/manual.cs50.io\/3\/wmempcpy) - copy memory area\n# [strings.h](https:\/\/manual.cs50.io\/#strings.h)\n- [bcmp](https:\/\/manual.cs50.io\/3\/bcmp) - compare byte sequences\n- [bcopy](https:\/\/manual.cs50.io\/3\/bcopy) - copy byte sequence\n- [bzero](https:\/\/manual.cs50.io\/3\/bzero) - zero a byte string\n- [explicit\\_bzero](https:\/\/manual.cs50.io\/3\/explicit_bzero) - zero a byte string\n- [ffs](https:\/\/manual.cs50.io\/3\/ffs) - find first bit set in a word\n- [ffsl](https:\/\/manual.cs50.io\/3\/ffsl) - find first bit set in a word\n- [ffsll](https:\/\/manual.cs50.io\/3\/ffsll) - find first bit set in a word\n- [index](https:\/\/manual.cs50.io\/3\/index) - locate character in string\n- [rindex](https:\/\/manual.cs50.io\/3\/rindex) - locate character in string\n- [strcasecmp](https:\/\/manual.cs50.io\/3\/strcasecmp) - compare two strings ignoring case compare two strings ignoring case\n- [string](https:\/\/manual.cs50.io\/3\/string) - string operations\n- [strncasecmp](https:\/\/manual.cs50.io\/3\/strncasecmp) - compare two strings ignoring case\n# [sys\/ipc.h](https:\/\/manual.cs50.io\/#sys\/ipc.h)\n- [ftok](https:\/\/manual.cs50.io\/3\/ftok) - convert a pathname and a project identifier to a Syste...\n# [sys\/mman.h](https:\/\/manual.cs50.io\/#sys\/mman.h)\n- [madvise](https:\/\/manual.cs50.io\/2\/madvise) - give advice about use of memory\n- [memfd\\_create](https:\/\/manual.cs50.io\/2\/memfd_create) - create an anonymous file\n- [mincore](https:\/\/manual.cs50.io\/2\/mincore) - determine whether pages are resident in memory\n- [mlock](https:\/\/manual.cs50.io\/2\/mlock) - lock and unlock memory\n- [mlock2](https:\/\/manual.cs50.io\/2\/mlock2) - lock and unlock memory\n- [mlockall](https:\/\/manual.cs50.io\/2\/mlockall) - lock and unlock memory\n- [mmap](https:\/\/manual.cs50.io\/2\/mmap) - map or unmap files or devices into memory\n- [mmap64](https:\/\/manual.cs50.io\/3\/mmap64) - map or unmap files or devices into memory\n- [mprotect](https:\/\/manual.cs50.io\/2\/mprotect) - set protection on a region of memory\n- [mremap](https:\/\/manual.cs50.io\/2\/mremap) - remap a virtual memory address\n- [msync](https:\/\/manual.cs50.io\/2\/msync) - synchronize a file with a memory map\n- [munlock](https:\/\/manual.cs50.io\/2\/munlock) - lock and unlock memory\n- [munlockall](https:\/\/manual.cs50.io\/2\/munlockall) - lock and unlock memory\n- [munmap](https:\/\/manual.cs50.io\/2\/munmap) - map or unmap files or devices into memory\n- [pkey\\_alloc](https:\/\/manual.cs50.io\/2\/pkey_alloc) - allocate or free a protection key\n- [pkey\\_free](https:\/\/manual.cs50.io\/2\/pkey_free) - allocate or free a protection key\n- [pkey\\_mprotect](https:\/\/manual.cs50.io\/2\/pkey_mprotect) - set protection on a region of memory\n- [posix\\_madvise](https:\/\/manual.cs50.io\/3\/posix_madvise) - give advice about patterns of memory usage\n- [process\\_madvise](https:\/\/manual.cs50.io\/2\/process_madvise) - give advice about use of memory to a process\n- [remap\\_file\\_pages](https:\/\/manual.cs50.io\/2\/remap_file_pages) - create a nonlinear file mapping\n- [shm\\_open](https:\/\/manual.cs50.io\/3\/shm_open) - create\/open or unlink POSIX shared memory objects\n- [shm\\_unlink](https:\/\/manual.cs50.io\/3\/shm_unlink) - create\/open or unlink POSIX shared memory objects\n# [sys\/msg.h](https:\/\/manual.cs50.io\/#sys\/msg.h)\n- [msgctl](https:\/\/manual.cs50.io\/2\/msgctl) - System V message control operations\n- [msgget](https:\/\/manual.cs50.io\/2\/msgget) - get a System V message queue identifier\n- [msgop](https:\/\/manual.cs50.io\/2\/msgop) - System V message queue operations\n- [msgrcv](https:\/\/manual.cs50.io\/2\/msgrcv) - System V message queue operations\n- [msgsnd](https:\/\/manual.cs50.io\/2\/msgsnd) - System V message queue operations\n# [sys\/resource.h](https:\/\/manual.cs50.io\/#sys\/resource.h)\n- [getpriority](https:\/\/manual.cs50.io\/2\/getpriority) - get\/set program scheduling priority\n- [getrlimit](https:\/\/manual.cs50.io\/2\/getrlimit) - get\/set resource limits\n- [getrusage](https:\/\/manual.cs50.io\/2\/getrusage) - get resource usage\n- [prlimit](https:\/\/manual.cs50.io\/2\/prlimit) - get\/set resource limits\n- [prlimit64](https:\/\/manual.cs50.io\/2\/prlimit64) - get\/set resource limits\n- [setpriority](https:\/\/manual.cs50.io\/2\/setpriority) - get\/set program scheduling priority\n- [setrlimit](https:\/\/manual.cs50.io\/2\/setrlimit) - get\/set resource limits\n- [ugetrlimit](https:\/\/manual.cs50.io\/2\/ugetrlimit) - get\/set resource limits\n- [vlimit](https:\/\/manual.cs50.io\/3\/vlimit) - get\/set resource limits\n- [vtimes](https:\/\/manual.cs50.io\/3\/vtimes) - get resource usage\n# [sys\/select.h](https:\/\/manual.cs50.io\/#sys\/select.h)\n- [\\_newselect](https:\/\/manual.cs50.io\/2\/_newselect) - synchronous I\/O multiplexing\n- [FD\\_CLR](https:\/\/manual.cs50.io\/3\/FD_CLR) - synchronous I\/O multiplexing\n- [FD\\_ISSET](https:\/\/manual.cs50.io\/3\/FD_ISSET) - synchronous I\/O multiplexing\n- [FD\\_SET](https:\/\/manual.cs50.io\/3\/FD_SET) - synchronous I\/O multiplexing\n- [FD\\_ZERO](https:\/\/manual.cs50.io\/3\/FD_ZERO) - synchronous I\/O multiplexing\n- [pselect](https:\/\/manual.cs50.io\/2\/pselect) - synchronous I\/O multiplexing\n- [pselect6](https:\/\/manual.cs50.io\/2\/pselect6) - synchronous I\/O multiplexing\n- [select](https:\/\/manual.cs50.io\/2\/select) - synchronous I\/O multiplexing\n# [sys\/sem.h](https:\/\/manual.cs50.io\/#sys\/sem.h)\n- [semctl](https:\/\/manual.cs50.io\/2\/semctl) - System V semaphore control operations\n- [semget](https:\/\/manual.cs50.io\/2\/semget) - get a System V semaphore set identifier\n- [semop](https:\/\/manual.cs50.io\/2\/semop) - System V semaphore operations\n- [semtimedop](https:\/\/manual.cs50.io\/2\/semtimedop) - System V semaphore operations\n# [sys\/shm.h](https:\/\/manual.cs50.io\/#sys\/shm.h)\n- [shmat](https:\/\/manual.cs50.io\/2\/shmat) - System V shared memory operations\n- [shmctl](https:\/\/manual.cs50.io\/2\/shmctl) - System V shared memory control\n- [shmdt](https:\/\/manual.cs50.io\/2\/shmdt) - System V shared memory operations\n- [shmget](https:\/\/manual.cs50.io\/2\/shmget) - allocates a System V shared memory segment\n- [shmop](https:\/\/manual.cs50.io\/2\/shmop) - System V shared memory operations\n# [sys\/socket.h](https:\/\/manual.cs50.io\/#sys\/socket.h)\n- [accept](https:\/\/manual.cs50.io\/2\/accept) - accept a connection on a socket\n- [accept4](https:\/\/manual.cs50.io\/2\/accept4) - accept a connection on a socket\n- [address\\_families](https:\/\/manual.cs50.io\/7\/address_families) - socket address families (domains)\n- [bind](https:\/\/manual.cs50.io\/2\/bind) - bind a name to a socket\n- [cmsg](https:\/\/manual.cs50.io\/3\/cmsg) - access ancillary data\n- [CMSG\\_ALIGN](https:\/\/manual.cs50.io\/3\/CMSG_ALIGN) - access ancillary data\n- [CMSG\\_DATA](https:\/\/manual.cs50.io\/3\/CMSG_DATA) - access ancillary data\n- [CMSG\\_FIRSTHDR](https:\/\/manual.cs50.io\/3\/CMSG_FIRSTHDR) - access ancillary data\n- [CMSG\\_LEN](https:\/\/manual.cs50.io\/3\/CMSG_LEN) - access ancillary data\n- [CMSG\\_NXTHDR](https:\/\/manual.cs50.io\/3\/CMSG_NXTHDR) - access ancillary data\n- [CMSG\\_SPACE](https:\/\/manual.cs50.io\/3\/CMSG_SPACE) - access ancillary data\n- [connect](https:\/\/manual.cs50.io\/2\/connect) - initiate a connection on a socket\n- [ddp](https:\/\/manual.cs50.io\/7\/ddp) - Linux AppleTalk protocol implementation\n- [getnameinfo](https:\/\/manual.cs50.io\/3\/getnameinfo) - address-to-name translation in protocol-independent ma...\n- [getpeername](https:\/\/manual.cs50.io\/2\/getpeername) - get name of connected peer socket\n- [getsockname](https:\/\/manual.cs50.io\/2\/getsockname) - get socket name\n- [getsockopt](https:\/\/manual.cs50.io\/2\/getsockopt) - get and set options on sockets\n- [inet](https:\/\/manual.cs50.io\/3\/inet) - Internet address manipulation routines\n- [inet\\_addr](https:\/\/manual.cs50.io\/3\/inet_addr) - Internet address manipulation routines\n- [inet\\_aton](https:\/\/manual.cs50.io\/3\/inet_aton) - Internet address manipulation routines\n- [inet\\_lnaof](https:\/\/manual.cs50.io\/3\/inet_lnaof) - Internet address manipulation routines\n- [inet\\_makeaddr](https:\/\/manual.cs50.io\/3\/inet_makeaddr) - Internet address manipulation routines\n- [inet\\_netof](https:\/\/manual.cs50.io\/3\/inet_netof) - Internet address manipulation routines\n- [inet\\_network](https:\/\/manual.cs50.io\/3\/inet_network) - Internet address manipulation routines\n- [inet\\_ntoa](https:\/\/manual.cs50.io\/3\/inet_ntoa) - Internet address manipulation routines\n- [ip](https:\/\/manual.cs50.io\/7\/ip) - Linux IPv4 protocol implementation\n- [ipv6](https:\/\/manual.cs50.io\/7\/ipv6) - Linux IPv6 protocol implementation\n- [listen](https:\/\/manual.cs50.io\/2\/listen) - listen for connections on a socket\n- [packet](https:\/\/manual.cs50.io\/7\/packet) - packet interface on device level\n- [raw](https:\/\/manual.cs50.io\/7\/raw) - Linux IPv4 raw sockets\n- [recv](https:\/\/manual.cs50.io\/2\/recv) - receive a message from a socket\n- [recvfrom](https:\/\/manual.cs50.io\/2\/recvfrom) - receive a message from a socket\n- [recvmmsg](https:\/\/manual.cs50.io\/2\/recvmmsg) - receive multiple messages on a socket\n- [recvmsg](https:\/\/manual.cs50.io\/2\/recvmsg) - receive a message from a socket\n- [send](https:\/\/manual.cs50.io\/2\/send) - send a message on a socket\n- [sendmmsg](https:\/\/manual.cs50.io\/2\/sendmmsg) - send multiple messages on a socket\n- [sendmsg](https:\/\/manual.cs50.io\/2\/sendmsg) - send a message on a socket\n- [sendto](https:\/\/manual.cs50.io\/2\/sendto) - send a message on a socket\n- [setsockopt](https:\/\/manual.cs50.io\/2\/setsockopt) - get and set options on sockets\n- [shutdown](https:\/\/manual.cs50.io\/2\/shutdown) - shut down part of a full-duplex connection\n- [sock\\_diag](https:\/\/manual.cs50.io\/7\/sock_diag) - obtaining information about sockets\n- [sockatmark](https:\/\/manual.cs50.io\/3\/sockatmark) - determine whether socket is at out-of-band mark\n- [socket](https:\/\/manual.cs50.io\/2\/socket) - create an endpoint for communication\n- [socket](https:\/\/manual.cs50.io\/7\/socket) - Linux socket interface\n- [socketpair](https:\/\/manual.cs50.io\/2\/socketpair) - create a pair of connected sockets\n- [tcp](https:\/\/manual.cs50.io\/7\/tcp) - TCP protocol\n- [udp](https:\/\/manual.cs50.io\/7\/udp) - User Datagram Protocol for IPv4\n- [udplite](https:\/\/manual.cs50.io\/7\/udplite) - Lightweight User Datagram Protocol\n- [unix](https:\/\/manual.cs50.io\/7\/unix) - sockets for local interprocess communication\n- [vsock](https:\/\/manual.cs50.io\/7\/vsock) - Linux VSOCK address family\n- [x25](https:\/\/manual.cs50.io\/7\/x25) - ITU-T X.25 \/ ISO\/IEC 8208 protocol interface\n# [sys\/stat.h](https:\/\/manual.cs50.io\/#sys\/stat.h)\n- [chmod](https:\/\/manual.cs50.io\/2\/chmod) - change permissions of a file\n- [fchmod](https:\/\/manual.cs50.io\/2\/fchmod) - change permissions of a file\n- [fchmodat](https:\/\/manual.cs50.io\/2\/fchmodat) - change permissions of a file\n- [fstat](https:\/\/manual.cs50.io\/2\/fstat) - get file status\n- [fstat64](https:\/\/manual.cs50.io\/2\/fstat64) - get file status\n- [fstatat](https:\/\/manual.cs50.io\/2\/fstatat) - get file status\n- [fstatat64](https:\/\/manual.cs50.io\/2\/fstatat64) - get file status\n- [futimens](https:\/\/manual.cs50.io\/3\/futimens) - change file timestamps with nanosecond precision\n- [isfdtype](https:\/\/manual.cs50.io\/3\/isfdtype) - test file type of a file descriptor\n- [lstat](https:\/\/manual.cs50.io\/2\/lstat) - get file status\n- [lstat64](https:\/\/manual.cs50.io\/2\/lstat64) - get file status\n- [mkdir](https:\/\/manual.cs50.io\/2\/mkdir) - create a directory\n- [mkdirat](https:\/\/manual.cs50.io\/2\/mkdirat) - create a directory\n- [mknod](https:\/\/manual.cs50.io\/2\/mknod) - create a special or ordinary file\n- [mknodat](https:\/\/manual.cs50.io\/2\/mknodat) - create a special or ordinary file\n- [newfstatat](https:\/\/manual.cs50.io\/2\/newfstatat) - get file status\n- [oldfstat](https:\/\/manual.cs50.io\/2\/oldfstat) - get file status\n- [oldlstat](https:\/\/manual.cs50.io\/2\/oldlstat) - get file status\n- [oldstat](https:\/\/manual.cs50.io\/2\/oldstat) - get file status\n- [stat](https:\/\/manual.cs50.io\/2\/stat) - get file status\n- [stat64](https:\/\/manual.cs50.io\/2\/stat64) - get file status\n- [statx](https:\/\/manual.cs50.io\/2\/statx) - get file status (extended)\n- [umask](https:\/\/manual.cs50.io\/2\/umask) - set file mode creation mask\n- [utimensat](https:\/\/manual.cs50.io\/2\/utimensat) - change file timestamps with nanosecond precision\n# [sys\/statvfs.h](https:\/\/manual.cs50.io\/#sys\/statvfs.h)\n- [fstatvfs](https:\/\/manual.cs50.io\/3\/fstatvfs) - get filesystem statistics\n- [statvfs](https:\/\/manual.cs50.io\/3\/statvfs) - get filesystem statistics\n# [sys\/time.h](https:\/\/manual.cs50.io\/#sys\/time.h)\n- [adjtime](https:\/\/manual.cs50.io\/3\/adjtime) - correct the time to synchronize the system clock\n- [futimes](https:\/\/manual.cs50.io\/3\/futimes) - change file timestamps\n- [futimesat](https:\/\/manual.cs50.io\/2\/futimesat) - change timestamps of a file relative to a directory fi...\n- [getitimer](https:\/\/manual.cs50.io\/2\/getitimer) - get or set value of an interval timer\n- [gettimeofday](https:\/\/manual.cs50.io\/2\/gettimeofday) - get \/ set time\n- [lutimes](https:\/\/manual.cs50.io\/3\/lutimes) - change file timestamps\n- [setitimer](https:\/\/manual.cs50.io\/2\/setitimer) - get or set value of an interval timer\n- [settimeofday](https:\/\/manual.cs50.io\/2\/settimeofday) - get \/ set time\n- [timeradd](https:\/\/manual.cs50.io\/3\/timeradd) - timeval operations\n- [timerclear](https:\/\/manual.cs50.io\/3\/timerclear) - timeval operations\n- [timercmp](https:\/\/manual.cs50.io\/3\/timercmp) - timeval operations\n- [timerisset](https:\/\/manual.cs50.io\/3\/timerisset) - timeval operations\n- [timersub](https:\/\/manual.cs50.io\/3\/timersub) - timeval operations\n- [TIMESPEC\\_TO\\_TIMEVAL](https:\/\/manual.cs50.io\/3\/TIMESPEC_TO_TIMEVAL) - convert between time structures\n- [TIMEVAL\\_TO\\_TIMESPEC](https:\/\/manual.cs50.io\/3\/TIMEVAL_TO_TIMESPEC) - convert between time structures\n# [sys\/times.h](https:\/\/manual.cs50.io\/#sys\/times.h)\n- [times](https:\/\/manual.cs50.io\/2\/times) - get process times\n# [sys\/types.h](https:\/\/manual.cs50.io\/#sys\/types.h)\n- [bindresvport](https:\/\/manual.cs50.io\/3\/bindresvport) - bind a socket to a privileged IP port\n- [closedir](https:\/\/manual.cs50.io\/3\/closedir) - close a directory\n- [db](https:\/\/manual.cs50.io\/3\/db) - database access methods\n- [dbopen](https:\/\/manual.cs50.io\/3\/dbopen) - database access methods\n- [dirfd](https:\/\/manual.cs50.io\/3\/dirfd) - get directory stream file descriptor\n- [endgrent](https:\/\/manual.cs50.io\/3\/endgrent) - get group file entry\n- [endpwent](https:\/\/manual.cs50.io\/3\/endpwent) - get password file entry\n- [fdopendir](https:\/\/manual.cs50.io\/3\/fdopendir) - open a directory\n- [freeaddrinfo](https:\/\/manual.cs50.io\/3\/freeaddrinfo) - network address and service translation\n- [freehostent](https:\/\/manual.cs50.io\/3\/freehostent) - get network hostnames and addresses\n- [freeifaddrs](https:\/\/manual.cs50.io\/3\/freeifaddrs) - get interface addresses\n- [fts](https:\/\/manual.cs50.io\/3\/fts) - traverse a file hierarchy\n- [fts\\_children](https:\/\/manual.cs50.io\/3\/fts_children) - traverse a file hierarchy\n- [fts\\_close](https:\/\/manual.cs50.io\/3\/fts_close) - traverse a file hierarchy\n- [fts\\_open](https:\/\/manual.cs50.io\/3\/fts_open) - traverse a file hierarchy\n- [fts\\_read](https:\/\/manual.cs50.io\/3\/fts_read) - traverse a file hierarchy\n- [fts\\_set](https:\/\/manual.cs50.io\/3\/fts_set) - traverse a file hierarchy\n- [gai\\_strerror](https:\/\/manual.cs50.io\/3\/gai_strerror) - network address and service translation\n- [getaddrinfo](https:\/\/manual.cs50.io\/3\/getaddrinfo) - network address and service translation\n- [getgrent](https:\/\/manual.cs50.io\/3\/getgrent) - get group file entry\n- [getgrgid](https:\/\/manual.cs50.io\/3\/getgrgid) - get group file entry\n- [getgrgid\\_r](https:\/\/manual.cs50.io\/3\/getgrgid_r) - get group file entry\n- [getgrnam](https:\/\/manual.cs50.io\/3\/getgrnam) - get group file entry\n- [getgrnam\\_r](https:\/\/manual.cs50.io\/3\/getgrnam_r) - get group file entry\n- [getifaddrs](https:\/\/manual.cs50.io\/3\/getifaddrs) - get interface addresses\n- [getipnodebyaddr](https:\/\/manual.cs50.io\/3\/getipnodebyaddr) - get network hostnames and addresses\n- [getipnodebyname](https:\/\/manual.cs50.io\/3\/getipnodebyname) - get network hostnames and addresses\n- [getpw](https:\/\/manual.cs50.io\/3\/getpw) - reconstruct password line entry\n- [getpwent](https:\/\/manual.cs50.io\/3\/getpwent) - get password file entry\n- [getpwnam](https:\/\/manual.cs50.io\/3\/getpwnam) - get password file entry\n- [getpwnam\\_r](https:\/\/manual.cs50.io\/3\/getpwnam_r) - get password file entry\n- [getpwuid](https:\/\/manual.cs50.io\/3\/getpwuid) - get password file entry\n- [getpwuid\\_r](https:\/\/manual.cs50.io\/3\/getpwuid_r) - get password file entry\n- [initgroups](https:\/\/manual.cs50.io\/3\/initgroups) - initialize the supplementary group access list\n- [lseek64](https:\/\/manual.cs50.io\/3\/lseek64) - reposition 64-bit read\/write file offset\n- [mkfifo](https:\/\/manual.cs50.io\/3\/mkfifo) - make a FIFO special file (a named pipe)\n- [mkfifoat](https:\/\/manual.cs50.io\/3\/mkfifoat) - make a FIFO special file (a named pipe)\n- [opendir](https:\/\/manual.cs50.io\/3\/opendir) - open a directory\n- [re\\_comp](https:\/\/manual.cs50.io\/3\/re_comp) - BSD regex functions\n- [re\\_exec](https:\/\/manual.cs50.io\/3\/re_exec) - BSD regex functions\n- [rewinddir](https:\/\/manual.cs50.io\/3\/rewinddir) - reset directory stream\n- [setgrent](https:\/\/manual.cs50.io\/3\/setgrent) - get group file entry\n- [setpwent](https:\/\/manual.cs50.io\/3\/setpwent) - get password file entry\n- [ustat](https:\/\/manual.cs50.io\/2\/ustat) - get filesystem statistics\n# [sys\/uio.h](https:\/\/manual.cs50.io\/#sys\/uio.h)\n- [preadv](https:\/\/manual.cs50.io\/2\/preadv) - read or write data into multiple buffers\n- [preadv2](https:\/\/manual.cs50.io\/2\/preadv2) - read or write data into multiple buffers\n- [process\\_vm\\_readv](https:\/\/manual.cs50.io\/2\/process_vm_readv) - transfer data between process address spaces\n- [process\\_vm\\_writev](https:\/\/manual.cs50.io\/2\/process_vm_writev) - transfer data between process address spaces\n- [pwritev](https:\/\/manual.cs50.io\/2\/pwritev) - read or write data into multiple buffers\n- [pwritev2](https:\/\/manual.cs50.io\/2\/pwritev2) - read or write data into multiple buffers\n- [readv](https:\/\/manual.cs50.io\/2\/readv) - read or write data into multiple buffers\n- [writev](https:\/\/manual.cs50.io\/2\/writev) - read or write data into multiple buffers\n# [sys\/utsname.h](https:\/\/manual.cs50.io\/#sys\/utsname.h)\n- [oldolduname](https:\/\/manual.cs50.io\/2\/oldolduname) - get name and information about current kernel\n- [olduname](https:\/\/manual.cs50.io\/2\/olduname) - get name and information about current kernel\n- [uname](https:\/\/manual.cs50.io\/2\/uname) - get name and information about current kernel\n# [sys\/wait.h](https:\/\/manual.cs50.io\/#sys\/wait.h)\n- [wait](https:\/\/manual.cs50.io\/2\/wait) - wait for process to change state\n- [wait3](https:\/\/manual.cs50.io\/2\/wait3) - wait for process to change state, BSD style\n- [wait4](https:\/\/manual.cs50.io\/2\/wait4) - wait for process to change state, BSD style\n- [waitid](https:\/\/manual.cs50.io\/2\/waitid) - wait for process to change state\n- [waitpid](https:\/\/manual.cs50.io\/2\/waitpid) - wait for process to change state\n# [syslog.h](https:\/\/manual.cs50.io\/#syslog.h)\n- [closelog](https:\/\/manual.cs50.io\/3\/closelog) - send messages to the system logger\n- [openlog](https:\/\/manual.cs50.io\/3\/openlog) - send messages to the system logger\n- [setlogmask](https:\/\/manual.cs50.io\/3\/setlogmask) - set log priority mask\n- [syslog](https:\/\/manual.cs50.io\/3\/syslog) - send messages to the system logger\n- [vsyslog](https:\/\/manual.cs50.io\/3\/vsyslog) - send messages to the system logger\n# [termios.h](https:\/\/manual.cs50.io\/#termios.h)\n- [cfgetispeed](https:\/\/manual.cs50.io\/3\/cfgetispeed) - get and set terminal attributes, line control, get and...\n- [cfgetospeed](https:\/\/manual.cs50.io\/3\/cfgetospeed) - get and set terminal attributes, line control, get and...\n- [cfmakeraw](https:\/\/manual.cs50.io\/3\/cfmakeraw) - get and set terminal attributes, line control, get and...\n- [cfsetispeed](https:\/\/manual.cs50.io\/3\/cfsetispeed) - get and set terminal attributes, line control, get and...\n- [cfsetospeed](https:\/\/manual.cs50.io\/3\/cfsetospeed) - get and set terminal attributes, line control, get and...\n- [cfsetspeed](https:\/\/manual.cs50.io\/3\/cfsetspeed) - get and set terminal attributes, line control, get and...\n- [tcdrain](https:\/\/manual.cs50.io\/3\/tcdrain) - get and set terminal attributes, line control, get and...\n- [tcflow](https:\/\/manual.cs50.io\/3\/tcflow) - get and set terminal attributes, line control, get and...\n- [tcflush](https:\/\/manual.cs50.io\/3\/tcflush) - get and set terminal attributes, line control, get and...\n- [tcgetattr](https:\/\/manual.cs50.io\/3\/tcgetattr) - get and set terminal attributes, line control, get and...\n- [tcgetsid](https:\/\/manual.cs50.io\/3\/tcgetsid) - get session ID\n- [tcsendbreak](https:\/\/manual.cs50.io\/3\/tcsendbreak) - get and set terminal attributes, line control, get and...\n- [tcsetattr](https:\/\/manual.cs50.io\/3\/tcsetattr) - get and set terminal attributes, line control, get and...\n- [termios](https:\/\/manual.cs50.io\/3\/termios) - get and set terminal attributes, line control, get and...\n# [time.h](https:\/\/manual.cs50.io\/#time.h)\n- [asctime](https:\/\/manual.cs50.io\/3\/asctime) - transform date and time to broken-down time or ASCII\n- [asctime\\_r](https:\/\/manual.cs50.io\/3\/asctime_r) - transform date and time to broken-down time or ASCII\n- [clock](https:\/\/manual.cs50.io\/3\/clock) - determine processor time\n- [clock\\_getcpuclockid](https:\/\/manual.cs50.io\/3\/clock_getcpuclockid) - obtain ID of a process CPU-time clock\n- [clock\\_getres](https:\/\/manual.cs50.io\/2\/clock_getres) - clock and time functions\n- [clock\\_gettime](https:\/\/manual.cs50.io\/2\/clock_gettime) - clock and time functions\n- [clock\\_nanosleep](https:\/\/manual.cs50.io\/2\/clock_nanosleep) - high-resolution sleep with specifiable clock\n- [clock\\_settime](https:\/\/manual.cs50.io\/2\/clock_settime) - clock and time functions\n- [ctime](https:\/\/manual.cs50.io\/3\/ctime) - transform date and time to broken-down time or ASCII\n- [ctime\\_r](https:\/\/manual.cs50.io\/3\/ctime_r) - transform date and time to broken-down time or ASCII\n- [daylight](https:\/\/manual.cs50.io\/3\/daylight) - initialize time conversion information\n- [difftime](https:\/\/manual.cs50.io\/3\/difftime) - calculate time difference\n- [dysize](https:\/\/manual.cs50.io\/3\/dysize) - get number of days for a given year\n- [getdate](https:\/\/manual.cs50.io\/3\/getdate) - convert a date-plus-time string to broken-down time\n- [getdate\\_err](https:\/\/manual.cs50.io\/3\/getdate_err) - convert a date-plus-time string to broken-down time\n- [getdate\\_r](https:\/\/manual.cs50.io\/3\/getdate_r) - convert a date-plus-time string to broken-down time\n- [gmtime](https:\/\/manual.cs50.io\/3\/gmtime) - transform date and time to broken-down time or ASCII\n- [gmtime\\_r](https:\/\/manual.cs50.io\/3\/gmtime_r) - transform date and time to broken-down time or ASCII\n- [localtime](https:\/\/manual.cs50.io\/3\/localtime) - transform date and time to broken-down time or ASCII\n- [localtime\\_r](https:\/\/manual.cs50.io\/3\/localtime_r) - transform date and time to broken-down time or ASCII\n- [mktime](https:\/\/manual.cs50.io\/3\/mktime) - transform date and time to broken-down time or ASCII\n- [nanosleep](https:\/\/manual.cs50.io\/2\/nanosleep) - high-resolution sleep\n- [stime](https:\/\/manual.cs50.io\/2\/stime) - set time\n- [strftime](https:\/\/manual.cs50.io\/3\/strftime) - format date and time\n- [strftime\\_l](https:\/\/manual.cs50.io\/3\/strftime_l) - format date and time\n- [strptime](https:\/\/manual.cs50.io\/3\/strptime) - convert a string representation of time to a time tm s...\n- [time](https:\/\/manual.cs50.io\/2\/time) - get time in seconds get time in seconds\n- [timegm](https:\/\/manual.cs50.io\/3\/timegm) - inverses of gmtime and localtime\n- [timelocal](https:\/\/manual.cs50.io\/3\/timelocal) - inverses of gmtime and localtime\n- [timer\\_create](https:\/\/manual.cs50.io\/2\/timer_create) - create a POSIX per-process timer\n- [timer\\_delete](https:\/\/manual.cs50.io\/2\/timer_delete) - delete a POSIX per-process timer\n- [timer\\_getoverrun](https:\/\/manual.cs50.io\/2\/timer_getoverrun) - get overrun count for a POSIX per-process timer\n- [timer\\_gettime](https:\/\/manual.cs50.io\/2\/timer_gettime) - arm\/disarm and fetch state of POSIX per-process timer\n- [timer\\_settime](https:\/\/manual.cs50.io\/2\/timer_settime) - arm\/disarm and fetch state of POSIX per-process timer\n- [timezone](https:\/\/manual.cs50.io\/3\/timezone) - initialize time conversion information\n- [tzname](https:\/\/manual.cs50.io\/3\/tzname) - initialize time conversion information\n- [tzset](https:\/\/manual.cs50.io\/3\/tzset) - initialize time conversion information\n# [ulimit.h](https:\/\/manual.cs50.io\/#ulimit.h)\n- [ulimit](https:\/\/manual.cs50.io\/3\/ulimit) - get and set user limits\n# [unistd.h](https:\/\/manual.cs50.io\/#unistd.h)\n- [\\_Exit](https:\/\/manual.cs50.io\/2\/_Exit) - terminate the calling process\n- [\\_exit](https:\/\/manual.cs50.io\/2\/_exit) - terminate the calling process\n- [\\_llseek](https:\/\/manual.cs50.io\/2\/_llseek) - reposition read\/write file offset\n- [\\_sysctl](https:\/\/manual.cs50.io\/2\/_sysctl) - read\/write system parameters\n- [access](https:\/\/manual.cs50.io\/2\/access) - check user's permissions for a file\n- [acct](https:\/\/manual.cs50.io\/2\/acct) - switch process accounting on or off\n- [alarm](https:\/\/manual.cs50.io\/2\/alarm) - set an alarm clock for delivery of a signal\n- [arch\\_prctl](https:\/\/manual.cs50.io\/2\/arch_prctl) - set architecture-specific thread state\n- [brk](https:\/\/manual.cs50.io\/2\/brk) - change data segment size\n- [capget](https:\/\/manual.cs50.io\/2\/capget) - set\/get capabilities of thread(s)\n- [capset](https:\/\/manual.cs50.io\/2\/capset) - set\/get capabilities of thread(s)\n- [chdir](https:\/\/manual.cs50.io\/2\/chdir) - change working directory\n- [chown](https:\/\/manual.cs50.io\/2\/chown) - change ownership of a file\n- [chown32](https:\/\/manual.cs50.io\/2\/chown32) - change ownership of a file\n- [chroot](https:\/\/manual.cs50.io\/2\/chroot) - change root directory\n- [close](https:\/\/manual.cs50.io\/2\/close) - close a file descriptor\n- [close\\_range](https:\/\/manual.cs50.io\/2\/close_range) - close all file descriptors in a given range\n- [confstr](https:\/\/manual.cs50.io\/3\/confstr) - get configuration dependent string variables\n- [copy\\_file\\_range](https:\/\/manual.cs50.io\/2\/copy_file_range) - Copy a range of data from one file to another\n- [cuserid](https:\/\/manual.cs50.io\/3\/cuserid) - get username\n- [daemon](https:\/\/manual.cs50.io\/3\/daemon) - run in the background\n- [delete\\_module](https:\/\/manual.cs50.io\/2\/delete_module) - unload a kernel module\n- [dup](https:\/\/manual.cs50.io\/2\/dup) - duplicate a file descriptor\n- [dup2](https:\/\/manual.cs50.io\/2\/dup2) - duplicate a file descriptor\n- [dup3](https:\/\/manual.cs50.io\/2\/dup3) - duplicate a file descriptor\n- [eaccess](https:\/\/manual.cs50.io\/3\/eaccess) - check effective user's permissions for a file\n- [encrypt](https:\/\/manual.cs50.io\/3\/encrypt) - encrypt 64-bit messages\n- [encrypt\\_r](https:\/\/manual.cs50.io\/3\/encrypt_r) - encrypt 64-bit messages\n- [endusershell](https:\/\/manual.cs50.io\/3\/endusershell) - get permitted user shells\n- [euidaccess](https:\/\/manual.cs50.io\/3\/euidaccess) - check effective user's permissions for a file\n- [exec](https:\/\/manual.cs50.io\/3\/exec) - execute a file\n- [execl](https:\/\/manual.cs50.io\/3\/execl) - execute a file\n- [execle](https:\/\/manual.cs50.io\/3\/execle) - execute a file\n- [execlp](https:\/\/manual.cs50.io\/3\/execlp) - execute a file\n- [execv](https:\/\/manual.cs50.io\/3\/execv) - execute a file\n- [execve](https:\/\/manual.cs50.io\/2\/execve) - execute program\n- [execveat](https:\/\/manual.cs50.io\/2\/execveat) - execute program relative to a directory file descriptor\n- [execvp](https:\/\/manual.cs50.io\/3\/execvp) - execute a file\n- [execvpe](https:\/\/manual.cs50.io\/3\/execvpe) - execute a file\n- [exit](https:\/\/manual.cs50.io\/2\/exit) - terminate the calling process\n- [exit\\_group](https:\/\/manual.cs50.io\/2\/exit_group) - exit all threads in a process\n- [faccessat](https:\/\/manual.cs50.io\/2\/faccessat) - check user's permissions for a file\n- [faccessat2](https:\/\/manual.cs50.io\/2\/faccessat2) - check user's permissions for a file\n- [fchdir](https:\/\/manual.cs50.io\/2\/fchdir) - change working directory\n- [fchown](https:\/\/manual.cs50.io\/2\/fchown) - change ownership of a file\n- [fchown32](https:\/\/manual.cs50.io\/2\/fchown32) - change ownership of a file\n- [fchownat](https:\/\/manual.cs50.io\/2\/fchownat) - change ownership of a file\n- [fdatasync](https:\/\/manual.cs50.io\/2\/fdatasync) - synchronize a file's in-core state with storage device\n- [fexecve](https:\/\/manual.cs50.io\/3\/fexecve) - execute program specified via file descriptor\n- [finit\\_module](https:\/\/manual.cs50.io\/2\/finit_module) - load a kernel module\n- [fork](https:\/\/manual.cs50.io\/2\/fork) - create a child process\n- [fpathconf](https:\/\/manual.cs50.io\/3\/fpathconf) - get configuration values for files\n- [fsync](https:\/\/manual.cs50.io\/2\/fsync) - synchronize a file's in-core state with storage device\n- [ftruncate](https:\/\/manual.cs50.io\/2\/ftruncate) - truncate a file to a specified length\n- [ftruncate64](https:\/\/manual.cs50.io\/2\/ftruncate64) - truncate a file to a specified length\n- [futex](https:\/\/manual.cs50.io\/2\/futex) - fast user-space locking\n- [get\\_current\\_dir\\_name](https:\/\/manual.cs50.io\/3\/get_current_dir_name) - get current working directory\n- [get\\_robust\\_list](https:\/\/manual.cs50.io\/2\/get_robust_list) - get\/set list of robust futexes\n- [get\\_thread\\_area](https:\/\/manual.cs50.io\/2\/get_thread_area) - manipulate thread-local storage information\n- [getcwd](https:\/\/manual.cs50.io\/2\/getcwd) - get current working directory\n- [getcwd](https:\/\/manual.cs50.io\/3\/getcwd) - get current working directory\n- [getdents](https:\/\/manual.cs50.io\/2\/getdents) - get directory entries\n- [getdents64](https:\/\/manual.cs50.io\/2\/getdents64) - get directory entries\n- [getdomainname](https:\/\/manual.cs50.io\/2\/getdomainname) - get\/set NIS domain name\n- [getdtablesize](https:\/\/manual.cs50.io\/3\/getdtablesize) - get file descriptor table size\n- [getegid](https:\/\/manual.cs50.io\/2\/getegid) - get group identity\n- [getegid32](https:\/\/manual.cs50.io\/2\/getegid32) - get group identity\n- [getentropy](https:\/\/manual.cs50.io\/3\/getentropy) - fill a buffer with random bytes\n- [geteuid](https:\/\/manual.cs50.io\/2\/geteuid) - get user identity\n- [geteuid32](https:\/\/manual.cs50.io\/2\/geteuid32) - get user identity\n- [getgid](https:\/\/manual.cs50.io\/2\/getgid) - get group identity\n- [getgid32](https:\/\/manual.cs50.io\/2\/getgid32) - get group identity\n- [getgroups](https:\/\/manual.cs50.io\/2\/getgroups) - get\/set list of supplementary group IDs\n- [getgroups32](https:\/\/manual.cs50.io\/2\/getgroups32) - get\/set list of supplementary group IDs\n- [gethostid](https:\/\/manual.cs50.io\/3\/gethostid) - get or set the unique identifier of the current host\n- [gethostname](https:\/\/manual.cs50.io\/2\/gethostname) - get\/set hostname\n- [getlogin](https:\/\/manual.cs50.io\/3\/getlogin) - get username\n- [getlogin\\_r](https:\/\/manual.cs50.io\/3\/getlogin_r) - get username\n- [getopt](https:\/\/manual.cs50.io\/3\/getopt) - Parse command-line options\n- [getopt\\_long](https:\/\/manual.cs50.io\/3\/getopt_long) - Parse command-line options\n- [getopt\\_long\\_only](https:\/\/manual.cs50.io\/3\/getopt_long_only) - Parse command-line options\n- [getpagesize](https:\/\/manual.cs50.io\/2\/getpagesize) - get memory page size\n- [getpass](https:\/\/manual.cs50.io\/3\/getpass) - get a password\n- [getpgid](https:\/\/manual.cs50.io\/2\/getpgid) - set\/get process group\n- [getpgrp](https:\/\/manual.cs50.io\/2\/getpgrp) - set\/get process group\n- [getpid](https:\/\/manual.cs50.io\/2\/getpid) - get process identification\n- [getppid](https:\/\/manual.cs50.io\/2\/getppid) - get process identification\n- [getresgid](https:\/\/manual.cs50.io\/2\/getresgid) - get real, effective, and saved user\/group IDs\n- [getresgid32](https:\/\/manual.cs50.io\/2\/getresgid32) - get real, effective, and saved user\/group IDs\n- [getresuid](https:\/\/manual.cs50.io\/2\/getresuid) - get real, effective, and saved user\/group IDs\n- [getresuid32](https:\/\/manual.cs50.io\/2\/getresuid32) - get real, effective, and saved user\/group IDs\n- [getsid](https:\/\/manual.cs50.io\/2\/getsid) - get session ID\n- [gettid](https:\/\/manual.cs50.io\/2\/gettid) - get thread identification\n- [getuid](https:\/\/manual.cs50.io\/2\/getuid) - get user identity\n- [getuid32](https:\/\/manual.cs50.io\/2\/getuid32) - get user identity\n- [getusershell](https:\/\/manual.cs50.io\/3\/getusershell) - get permitted user shells\n- [getwd](https:\/\/manual.cs50.io\/3\/getwd) - get current working directory\n- [group\\_member](https:\/\/manual.cs50.io\/3\/group_member) - test whether a process is in a group\n- [idle](https:\/\/manual.cs50.io\/2\/idle) - make process 0 idle\n- [init\\_module](https:\/\/manual.cs50.io\/2\/init_module) - load a kernel module\n- [io\\_cancel](https:\/\/manual.cs50.io\/2\/io_cancel) - cancel an outstanding asynchronous I\/O operation\n- [io\\_destroy](https:\/\/manual.cs50.io\/2\/io_destroy) - destroy an asynchronous I\/O context\n- [io\\_getevents](https:\/\/manual.cs50.io\/2\/io_getevents) - read asynchronous I\/O events from the completion queue\n- [ioprio\\_get](https:\/\/manual.cs50.io\/2\/ioprio_get) - get\/set I\/O scheduling class and priority\n- [ioprio\\_set](https:\/\/manual.cs50.io\/2\/ioprio_set) - get\/set I\/O scheduling class and priority\n- [ipc](https:\/\/manual.cs50.io\/2\/ipc) - System V IPC system calls\n- [isatty](https:\/\/manual.cs50.io\/3\/isatty) - test whether a file descriptor refers to a terminal\n- [kcmp](https:\/\/manual.cs50.io\/2\/kcmp) - compare two processes to determine if they share a ker...\n- [kexec\\_file\\_load](https:\/\/manual.cs50.io\/2\/kexec_file_load) - load a new kernel for later execution\n- [kexec\\_load](https:\/\/manual.cs50.io\/2\/kexec_load) - load a new kernel for later execution\n- [keyctl](https:\/\/manual.cs50.io\/2\/keyctl) - manipulate the kernel's key management facility\n- [klogctl](https:\/\/manual.cs50.io\/3\/klogctl) - read and\/or clear kernel message ring buffer; set cons...\n- [lchown](https:\/\/manual.cs50.io\/2\/lchown) - change ownership of a file\n- [lchown32](https:\/\/manual.cs50.io\/2\/lchown32) - change ownership of a file\n- [link](https:\/\/manual.cs50.io\/2\/link) - make a new name for a file\n- [linkat](https:\/\/manual.cs50.io\/2\/linkat) - make a new name for a file\n- [llseek](https:\/\/manual.cs50.io\/2\/llseek) - reposition read\/write file offset\n- [lockf](https:\/\/manual.cs50.io\/3\/lockf) - apply, test or remove a POSIX lock on an open file\n- [lookup\\_dcookie](https:\/\/manual.cs50.io\/2\/lookup_dcookie) - return a directory entry's path\n- [lseek](https:\/\/manual.cs50.io\/2\/lseek) - reposition read\/write file offset\n- [membarrier](https:\/\/manual.cs50.io\/2\/membarrier) - issue memory barriers on a set of threads\n- [memfd\\_secret](https:\/\/manual.cs50.io\/2\/memfd_secret) - create an anonymous RAM-based file to access secret me...\n- [mmap2](https:\/\/manual.cs50.io\/2\/mmap2) - map files or devices into memory\n- [modify\\_ldt](https:\/\/manual.cs50.io\/2\/modify_ldt) - get or set a per-process LDT entry\n- [mount\\_setattr](https:\/\/manual.cs50.io\/2\/mount_setattr) - change properties of a mount or mount tree\n- [mq\\_getsetattr](https:\/\/manual.cs50.io\/2\/mq_getsetattr) - get\/set message queue attributes\n- [nice](https:\/\/manual.cs50.io\/2\/nice) - change process priority\n- [openat2](https:\/\/manual.cs50.io\/2\/openat2) - open and possibly create a file (extended)\n- [optarg](https:\/\/manual.cs50.io\/3\/optarg) - Parse command-line options\n- [opterr](https:\/\/manual.cs50.io\/3\/opterr) - Parse command-line options\n- [optind](https:\/\/manual.cs50.io\/3\/optind) - Parse command-line options\n- [optopt](https:\/\/manual.cs50.io\/3\/optopt) - Parse command-line options\n- [pathconf](https:\/\/manual.cs50.io\/3\/pathconf) - get configuration values for files\n- [pause](https:\/\/manual.cs50.io\/2\/pause) - wait for signal\n- [perf\\_event\\_open](https:\/\/manual.cs50.io\/2\/perf_event_open) - set up performance monitoring\n- [pidfd\\_getfd](https:\/\/manual.cs50.io\/2\/pidfd_getfd) - obtain a duplicate of another process's file descriptor\n- [pidfd\\_open](https:\/\/manual.cs50.io\/2\/pidfd_open) - obtain a file descriptor that refers to a process\n- [pidfd\\_send\\_signal](https:\/\/manual.cs50.io\/2\/pidfd_send_signal) - send a signal to a process specified by a file descri...\n- [pipe](https:\/\/manual.cs50.io\/2\/pipe) - create pipe\n- [pipe2](https:\/\/manual.cs50.io\/2\/pipe2) - create pipe\n- [pivot\\_root](https:\/\/manual.cs50.io\/2\/pivot_root) - change the root mount\n- [pread](https:\/\/manual.cs50.io\/2\/pread) - read from or write to a file descriptor at a given offset\n- [pread64](https:\/\/manual.cs50.io\/2\/pread64) - read from or write to a file descriptor at a given offset\n- [profil](https:\/\/manual.cs50.io\/3\/profil) - execution time profile\n- [pwrite](https:\/\/manual.cs50.io\/2\/pwrite) - read from or write to a file descriptor at a given offset\n- [pwrite64](https:\/\/manual.cs50.io\/2\/pwrite64) - read from or write to a file descriptor at a given offset\n- [read](https:\/\/manual.cs50.io\/2\/read) - read from a file descriptor\n- [readdir](https:\/\/manual.cs50.io\/2\/readdir) - read directory entry\n- [readlink](https:\/\/manual.cs50.io\/2\/readlink) - read value of a symbolic link\n- [readlinkat](https:\/\/manual.cs50.io\/2\/readlinkat) - read value of a symbolic link\n- [reboot](https:\/\/manual.cs50.io\/2\/reboot) - reboot or enable\/disable Ctrl-Alt-Del\n- [rmdir](https:\/\/manual.cs50.io\/2\/rmdir) - delete a directory\n- [rt\\_sigqueueinfo](https:\/\/manual.cs50.io\/2\/rt_sigqueueinfo) - queue a signal and data\n- [rt\\_tgsigqueueinfo](https:\/\/manual.cs50.io\/2\/rt_tgsigqueueinfo) - queue a signal and data\n- [s390\\_guarded\\_storage](https:\/\/manual.cs50.io\/2\/s390_guarded_storage) - operations with z\/Architecture guarded storage fac...\n- [s390\\_pci\\_mmio\\_read](https:\/\/manual.cs50.io\/2\/s390_pci_mmio_read) - transfer data to\/from PCI MMIO memory page\n- [s390\\_pci\\_mmio\\_write](https:\/\/manual.cs50.io\/2\/s390_pci_mmio_write) - transfer data to\/from PCI MMIO memory page\n- [s390\\_runtime\\_instr](https:\/\/manual.cs50.io\/2\/s390_runtime_instr) - enable\/disable s390 CPU run-time instrumentation\n- [s390\\_sthyi](https:\/\/manual.cs50.io\/2\/s390_sthyi) - emulate STHYI instruction\n- [sbrk](https:\/\/manual.cs50.io\/2\/sbrk) - change data segment size\n- [sched\\_getattr](https:\/\/manual.cs50.io\/2\/sched_getattr) - set and get scheduling policy and attributes\n- [sched\\_setattr](https:\/\/manual.cs50.io\/2\/sched_setattr) - set and get scheduling policy and attributes\n- [seccomp](https:\/\/manual.cs50.io\/2\/seccomp) - operate on Secure Computing state of the process\n- [set\\_robust\\_list](https:\/\/manual.cs50.io\/2\/set_robust_list) - get\/set list of robust futexes\n- [set\\_thread\\_area](https:\/\/manual.cs50.io\/2\/set_thread_area) - manipulate thread-local storage information\n- [set\\_tid\\_address](https:\/\/manual.cs50.io\/2\/set_tid_address) - set pointer to thread ID\n- [setdomainname](https:\/\/manual.cs50.io\/2\/setdomainname) - get\/set NIS domain name\n- [setegid](https:\/\/manual.cs50.io\/2\/setegid) - set effective user or group ID\n- [seteuid](https:\/\/manual.cs50.io\/2\/seteuid) - set effective user or group ID\n- [setgid](https:\/\/manual.cs50.io\/2\/setgid) - set group identity\n- [setgid32](https:\/\/manual.cs50.io\/2\/setgid32) - set group identity\n- [setgroups](https:\/\/manual.cs50.io\/2\/setgroups) - get\/set list of supplementary group IDs\n- [setgroups32](https:\/\/manual.cs50.io\/2\/setgroups32) - get\/set list of supplementary group IDs\n- [sethostid](https:\/\/manual.cs50.io\/3\/sethostid) - get or set the unique identifier of the current host\n- [sethostname](https:\/\/manual.cs50.io\/2\/sethostname) - get\/set hostname\n- [setkey](https:\/\/manual.cs50.io\/3\/setkey) - encrypt 64-bit messages\n- [setkey\\_r](https:\/\/manual.cs50.io\/3\/setkey_r) - encrypt 64-bit messages\n- [setpgid](https:\/\/manual.cs50.io\/2\/setpgid) - set\/get process group\n- [setpgrp](https:\/\/manual.cs50.io\/2\/setpgrp) - set\/get process group\n- [setregid](https:\/\/manual.cs50.io\/2\/setregid) - set real and\/or effective user or group ID\n- [setregid32](https:\/\/manual.cs50.io\/2\/setregid32) - set real and\/or effective user or group ID\n- [setresgid](https:\/\/manual.cs50.io\/2\/setresgid) - set real, effective, and saved user or group ID\n- [setresgid32](https:\/\/manual.cs50.io\/2\/setresgid32) - set real, effective, and saved user or group ID\n- [setresuid](https:\/\/manual.cs50.io\/2\/setresuid) - set real, effective, and saved user or group ID\n- [setresuid32](https:\/\/manual.cs50.io\/2\/setresuid32) - set real, effective, and saved user or group ID\n- [setreuid](https:\/\/manual.cs50.io\/2\/setreuid) - set real and\/or effective user or group ID\n- [setreuid32](https:\/\/manual.cs50.io\/2\/setreuid32) - set real and\/or effective user or group ID\n- [setsid](https:\/\/manual.cs50.io\/2\/setsid) - creates a session and sets the process group ID\n- [setuid](https:\/\/manual.cs50.io\/2\/setuid) - set user identity\n- [setuid32](https:\/\/manual.cs50.io\/2\/setuid32) - set user identity\n- [setup](https:\/\/manual.cs50.io\/2\/setup) - setup devices and filesystems, mount root filesystem\n- [setusershell](https:\/\/manual.cs50.io\/3\/setusershell) - get permitted user shells\n- [sgetmask](https:\/\/manual.cs50.io\/2\/sgetmask) - manipulation of signal mask (obsolete)\n- [sleep](https:\/\/manual.cs50.io\/3\/sleep) - sleep for a specified number of seconds\n- [socketcall](https:\/\/manual.cs50.io\/2\/socketcall) - socket system calls\n- [spu\\_create](https:\/\/manual.cs50.io\/2\/spu_create) - create a new spu context\n- [spu\\_run](https:\/\/manual.cs50.io\/2\/spu_run) - execute an SPU context\n- [ssetmask](https:\/\/manual.cs50.io\/2\/ssetmask) - manipulation of signal mask (obsolete)\n- [subpage\\_prot](https:\/\/manual.cs50.io\/2\/subpage_prot) - define a subpage protection for an address range\n- [swab](https:\/\/manual.cs50.io\/3\/swab) - swap adjacent bytes\n- [symlink](https:\/\/manual.cs50.io\/2\/symlink) - make a new name for a file\n- [symlinkat](https:\/\/manual.cs50.io\/2\/symlinkat) - make a new name for a file\n- [sync](https:\/\/manual.cs50.io\/2\/sync) - commit filesystem caches to disk\n- [syncfs](https:\/\/manual.cs50.io\/2\/syncfs) - commit filesystem caches to disk\n- [syscall](https:\/\/manual.cs50.io\/2\/syscall) - indirect system call\n- [sysconf](https:\/\/manual.cs50.io\/3\/sysconf) - get configuration information at run time\n- [sysctl](https:\/\/manual.cs50.io\/2\/sysctl) - read\/write system parameters\n- [syslog](https:\/\/manual.cs50.io\/2\/syslog) - read and\/or clear kernel message ring buffer; set cons...\n- [tcgetpgrp](https:\/\/manual.cs50.io\/3\/tcgetpgrp) - get and set terminal foreground process group\n- [tcsetpgrp](https:\/\/manual.cs50.io\/3\/tcsetpgrp) - get and set terminal foreground process group\n- [tgkill](https:\/\/manual.cs50.io\/2\/tgkill) - send a signal to a thread\n- [tkill](https:\/\/manual.cs50.io\/2\/tkill) - send a signal to a thread\n- [truncate](https:\/\/manual.cs50.io\/2\/truncate) - truncate a file to a specified length\n- [truncate64](https:\/\/manual.cs50.io\/2\/truncate64) - truncate a file to a specified length\n- [ttyname](https:\/\/manual.cs50.io\/3\/ttyname) - return name of a terminal\n- [ttyname\\_r](https:\/\/manual.cs50.io\/3\/ttyname_r) - return name of a terminal\n- [ualarm](https:\/\/manual.cs50.io\/3\/ualarm) - schedule signal after given number of microseconds\n- [unlink](https:\/\/manual.cs50.io\/2\/unlink) - delete a name and possibly the file it refers to\n- [unlinkat](https:\/\/manual.cs50.io\/2\/unlinkat) - delete a name and possibly the file it refers to\n- [uselib](https:\/\/manual.cs50.io\/2\/uselib) - load shared library\n- [userfaultfd](https:\/\/manual.cs50.io\/2\/userfaultfd) - create a file descriptor for handling page faults in u...\n- [usleep](https:\/\/manual.cs50.io\/3\/usleep) - suspend execution for microsecond intervals\n- [vfork](https:\/\/manual.cs50.io\/2\/vfork) - create a child process and block parent\n- [vhangup](https:\/\/manual.cs50.io\/2\/vhangup) - virtually hangup the current terminal\n- [write](https:\/\/manual.cs50.io\/2\/write) - write to a file descriptor\n# [utime.h](https:\/\/manual.cs50.io\/#utime.h)\n- [utime](https:\/\/manual.cs50.io\/2\/utime) - change file last access and modification times\n- [utimes](https:\/\/manual.cs50.io\/2\/utimes) - change file last access and modification times\n# [utmpx.h](https:\/\/manual.cs50.io\/#utmpx.h)\n- [getutmp](https:\/\/manual.cs50.io\/3\/getutmp) - copy utmp structure to utmpx, and vice versa\n- [getutmpx](https:\/\/manual.cs50.io\/3\/getutmpx) - copy utmp structure to utmpx, and vice versa\n# [wchar.h](https:\/\/manual.cs50.io\/#wchar.h)\n- [btowc](https:\/\/manual.cs50.io\/3\/btowc) - convert single byte to wide character\n- [fgetws](https:\/\/manual.cs50.io\/3\/fgetws) - read a wide-character string from a FILE stream\n- [fputws](https:\/\/manual.cs50.io\/3\/fputws) - write a wide-character string to a FILE stream\n- [fwide](https:\/\/manual.cs50.io\/3\/fwide) - set and determine the orientation of a FILE stream\n- [getwchar](https:\/\/manual.cs50.io\/3\/getwchar) - read a wide character from standard input\n- [mbrlen](https:\/\/manual.cs50.io\/3\/mbrlen) - determine number of bytes in next multibyte character\n- [mbrtowc](https:\/\/manual.cs50.io\/3\/mbrtowc) - convert a multibyte sequence to a wide character\n- [mbsinit](https:\/\/manual.cs50.io\/3\/mbsinit) - test for initial shift state\n- [mbsnrtowcs](https:\/\/manual.cs50.io\/3\/mbsnrtowcs) - convert a multibyte string to a wide-character string\n- [mbsrtowcs](https:\/\/manual.cs50.io\/3\/mbsrtowcs) - convert a multibyte string to a wide-character string ...\n- [putwchar](https:\/\/manual.cs50.io\/3\/putwchar) - write a wide character to standard output\n- [ungetwc](https:\/\/manual.cs50.io\/3\/ungetwc) - push back a wide character onto a FILE stream\n- [wcpcpy](https:\/\/manual.cs50.io\/3\/wcpcpy) - copy a wide-character string, returning a pointer to i...\n- [wcpncpy](https:\/\/manual.cs50.io\/3\/wcpncpy) - copy a fixed-size string of wide characters, returning...\n- [wcrtomb](https:\/\/manual.cs50.io\/3\/wcrtomb) - convert a wide character to a multibyte sequence\n- [wcscasecmp](https:\/\/manual.cs50.io\/3\/wcscasecmp) - compare two wide-character strings, ignoring case\n- [wcscat](https:\/\/manual.cs50.io\/3\/wcscat) - concatenate two wide-character strings\n- [wcschr](https:\/\/manual.cs50.io\/3\/wcschr) - search a wide character in a wide-character string\n- [wcscmp](https:\/\/manual.cs50.io\/3\/wcscmp) - compare two wide-character strings\n- [wcscpy](https:\/\/manual.cs50.io\/3\/wcscpy) - copy a wide-character string\n- [wcscspn](https:\/\/manual.cs50.io\/3\/wcscspn) - search a wide-character string for any of a set of wid...\n- [wcsdup](https:\/\/manual.cs50.io\/3\/wcsdup) - duplicate a wide-character string\n- [wcslen](https:\/\/manual.cs50.io\/3\/wcslen) - determine the length of a wide-character string\n- [wcsncasecmp](https:\/\/manual.cs50.io\/3\/wcsncasecmp) - compare two fixed-size wide-character strings, ignorin...\n- [wcsncat](https:\/\/manual.cs50.io\/3\/wcsncat) - concatenate two wide-character strings\n- [wcsncmp](https:\/\/manual.cs50.io\/3\/wcsncmp) - compare two fixed-size wide-character strings\n- [wcsncpy](https:\/\/manual.cs50.io\/3\/wcsncpy) - copy a fixed-size string of wide characters\n- [wcsnlen](https:\/\/manual.cs50.io\/3\/wcsnlen) - determine the length of a fixed-size wide-character st...\n- [wcsnrtombs](https:\/\/manual.cs50.io\/3\/wcsnrtombs) - convert a wide-character string to a multibyte string\n- [wcspbrk](https:\/\/manual.cs50.io\/3\/wcspbrk) - search a wide-character string for any of a set of wid...\n- [wcsrchr](https:\/\/manual.cs50.io\/3\/wcsrchr) - search a wide character in a wide-character string\n- [wcsrtombs](https:\/\/manual.cs50.io\/3\/wcsrtombs) - convert a wide-character string to a multibyte string\n- [wcsspn](https:\/\/manual.cs50.io\/3\/wcsspn) - get length of a prefix wide-character substring\n- [wcsstr](https:\/\/manual.cs50.io\/3\/wcsstr) - locate a substring in a wide-character string\n- [wcstok](https:\/\/manual.cs50.io\/3\/wcstok) - split wide-character string into tokens\n- [wcswidth](https:\/\/manual.cs50.io\/3\/wcswidth) - determine columns needed for a fixed-size wide-charact...\n- [wctob](https:\/\/manual.cs50.io\/3\/wctob) - try to represent a wide character as a single byte\n- [wcwidth](https:\/\/manual.cs50.io\/3\/wcwidth) - determine columns needed for a wide character\n- [wmemchr](https:\/\/manual.cs50.io\/3\/wmemchr) - search a wide character in a wide-character array\n- [wmemcmp](https:\/\/manual.cs50.io\/3\/wmemcmp) - compare two arrays of wide-characters\n- [wmemcpy](https:\/\/manual.cs50.io\/3\/wmemcpy) - copy an array of wide-characters\n- [wmemmove](https:\/\/manual.cs50.io\/3\/wmemmove) - copy an array of wide-characters\n- [wmemset](https:\/\/manual.cs50.io\/3\/wmemset) - fill an array of wide-characters with a constant wide ...\n# [wctype.h](https:\/\/manual.cs50.io\/#wctype.h)\n- [iswalnum](https:\/\/manual.cs50.io\/3\/iswalnum) - test for alphanumeric wide character\n- [iswalpha](https:\/\/manual.cs50.io\/3\/iswalpha) - test for alphabetic wide character\n- [iswblank](https:\/\/manual.cs50.io\/3\/iswblank) - test for whitespace wide character\n- [iswcntrl](https:\/\/manual.cs50.io\/3\/iswcntrl) - test for control wide character\n- [iswctype](https:\/\/manual.cs50.io\/3\/iswctype) - wide-character classification\n- [iswdigit](https:\/\/manual.cs50.io\/3\/iswdigit) - test for decimal digit wide character\n- [iswgraph](https:\/\/manual.cs50.io\/3\/iswgraph) - test for graphic wide character\n- [iswlower](https:\/\/manual.cs50.io\/3\/iswlower) - test for lowercase wide character\n- [iswprint](https:\/\/manual.cs50.io\/3\/iswprint) - test for printing wide character\n- [iswpunct](https:\/\/manual.cs50.io\/3\/iswpunct) - test for punctuation or symbolic wide character\n- [iswspace](https:\/\/manual.cs50.io\/3\/iswspace) - test for whitespace wide character\n- [iswupper](https:\/\/manual.cs50.io\/3\/iswupper) - test for uppercase wide character\n- [iswxdigit](https:\/\/manual.cs50.io\/3\/iswxdigit) - test for hexadecimal digit wide character\n- [towctrans](https:\/\/manual.cs50.io\/3\/towctrans) - wide-character transliteration\n- [towlower](https:\/\/manual.cs50.io\/3\/towlower) - convert a wide character to lowercase\n- [towlower\\_l](https:\/\/manual.cs50.io\/3\/towlower_l) - convert a wide character to lowercase\n- [towupper](https:\/\/manual.cs50.io\/3\/towupper) - convert a wide character to uppercase\n- [towupper\\_l](https:\/\/manual.cs50.io\/3\/towupper_l) - convert a wide character to uppercase\n- [wctrans](https:\/\/manual.cs50.io\/3\/wctrans) - wide-character translation mapping\n- [wctype](https:\/\/manual.cs50.io\/3\/wctype) - wide-character classification\n# [wordexp.h](https:\/\/manual.cs50.io\/#wordexp.h)\n- [wordexp](https:\/\/manual.cs50.io\/3\/wordexp) - perform word expansion like a posix-shell\n- [wordfree](https:\/\/manual.cs50.io\/3\/wordfree) - perform word expansion like a posix-shell","attrs_readable_markdown":"Manual pages for the C standard library, the C POSIX library, and the CS50 Library for [those less comfortable]().\n\n## [aio.h](https:\/\/manual.cs50.io\/#aio.h)\n- [aio\\_cancel](https:\/\/manual.cs50.io\/3\/aio_cancel) - cancel an outstanding asynchronous I\/O request\n- [aio\\_error](https:\/\/manual.cs50.io\/3\/aio_error) - get error status of asynchronous I\/O operation\n- [aio\\_fsync](https:\/\/manual.cs50.io\/3\/aio_fsync) - asynchronous file synchronization\n- [aio\\_init](https:\/\/manual.cs50.io\/3\/aio_init) - asynchronous I\/O initialization\n- [aio\\_read](https:\/\/manual.cs50.io\/3\/aio_read) - asynchronous read\n- [aio\\_return](https:\/\/manual.cs50.io\/3\/aio_return) - get return status of asynchronous I\/O operation\n- [aio\\_suspend](https:\/\/manual.cs50.io\/3\/aio_suspend) - wait for asynchronous I\/O operation or timeout\n- [aio\\_write](https:\/\/manual.cs50.io\/3\/aio_write) - asynchronous write\n- [lio\\_listio](https:\/\/manual.cs50.io\/3\/lio_listio) - initiate a list of I\/O requests\n## [arpa\/inet.h](https:\/\/manual.cs50.io\/#arpa\/inet.h)\n- [byteorder](https:\/\/manual.cs50.io\/3\/byteorder) - convert values between host and network byte order\n- [htonl](https:\/\/manual.cs50.io\/3\/htonl) - convert values between host and network byte order\n- [htons](https:\/\/manual.cs50.io\/3\/htons) - convert values between host and network byte order\n- [inet\\_net\\_ntop](https:\/\/manual.cs50.io\/3\/inet_net_ntop) - Internet network number conversion\n- [inet\\_net\\_pton](https:\/\/manual.cs50.io\/3\/inet_net_pton) - Internet network number conversion\n- [inet\\_ntop](https:\/\/manual.cs50.io\/3\/inet_ntop) - convert IPv4 and IPv6 addresses from binary to text form\n- [inet\\_pton](https:\/\/manual.cs50.io\/3\/inet_pton) - convert IPv4 and IPv6 addresses from text to binary form\n- [ntohl](https:\/\/manual.cs50.io\/3\/ntohl) - convert values between host and network byte order\n- [ntohs](https:\/\/manual.cs50.io\/3\/ntohs) - convert values between host and network byte order\n## [assert.h](https:\/\/manual.cs50.io\/#assert.h)\n- [\\_Static\\_assert](https:\/\/manual.cs50.io\/3\/_Static_assert) - fail compilation if assertion is false\n- [assert](https:\/\/manual.cs50.io\/3\/assert) - abort the program if assertion is false\n- [assert\\_perror](https:\/\/manual.cs50.io\/3\/assert_perror) - test errnum and abort\n- [static\\_assert](https:\/\/manual.cs50.io\/3\/static_assert) - fail compilation if assertion is false\n## [complex.h](https:\/\/manual.cs50.io\/#complex.h)\n- [cabs](https:\/\/manual.cs50.io\/3\/cabs) - absolute value of a complex number\n- [cabsf](https:\/\/manual.cs50.io\/3\/cabsf) - absolute value of a complex number\n- [cabsl](https:\/\/manual.cs50.io\/3\/cabsl) - absolute value of a complex number\n- [cacos](https:\/\/manual.cs50.io\/3\/cacos) - complex arc cosine\n- [cacosf](https:\/\/manual.cs50.io\/3\/cacosf) - complex arc cosine\n- [cacosh](https:\/\/manual.cs50.io\/3\/cacosh) - complex arc hyperbolic cosine\n- [cacoshf](https:\/\/manual.cs50.io\/3\/cacoshf) - complex arc hyperbolic cosine\n- [cacoshl](https:\/\/manual.cs50.io\/3\/cacoshl) - complex arc hyperbolic cosine\n- [cacosl](https:\/\/manual.cs50.io\/3\/cacosl) - complex arc cosine\n- [carg](https:\/\/manual.cs50.io\/3\/carg) - calculate the complex argument\n- [cargf](https:\/\/manual.cs50.io\/3\/cargf) - calculate the complex argument\n- [cargl](https:\/\/manual.cs50.io\/3\/cargl) - calculate the complex argument\n- [casin](https:\/\/manual.cs50.io\/3\/casin) - complex arc sine\n- [casinf](https:\/\/manual.cs50.io\/3\/casinf) - complex arc sine\n- [casinh](https:\/\/manual.cs50.io\/3\/casinh) - complex arc sine hyperbolic\n- [casinhf](https:\/\/manual.cs50.io\/3\/casinhf) - complex arc sine hyperbolic\n- [casinhl](https:\/\/manual.cs50.io\/3\/casinhl) - complex arc sine hyperbolic\n- [casinl](https:\/\/manual.cs50.io\/3\/casinl) - complex arc sine\n- [catan](https:\/\/manual.cs50.io\/3\/catan) - complex arc tangents\n- [catanf](https:\/\/manual.cs50.io\/3\/catanf) - complex arc tangents\n- [catanh](https:\/\/manual.cs50.io\/3\/catanh) - complex arc tangents hyperbolic\n- [catanhf](https:\/\/manual.cs50.io\/3\/catanhf) - complex arc tangents hyperbolic\n- [catanhl](https:\/\/manual.cs50.io\/3\/catanhl) - complex arc tangents hyperbolic\n- [catanl](https:\/\/manual.cs50.io\/3\/catanl) - complex arc tangents\n- [ccos](https:\/\/manual.cs50.io\/3\/ccos) - complex cosine function\n- [ccosf](https:\/\/manual.cs50.io\/3\/ccosf) - complex cosine function\n- [ccosh](https:\/\/manual.cs50.io\/3\/ccosh) - complex hyperbolic cosine\n- [ccoshf](https:\/\/manual.cs50.io\/3\/ccoshf) - complex hyperbolic cosine\n- [ccoshl](https:\/\/manual.cs50.io\/3\/ccoshl) - complex hyperbolic cosine\n- [ccosl](https:\/\/manual.cs50.io\/3\/ccosl) - complex cosine function\n- [cexp](https:\/\/manual.cs50.io\/3\/cexp) - complex exponential function\n- [cexp2](https:\/\/manual.cs50.io\/3\/cexp2) - base-2 exponent of a complex number\n- [cexp2f](https:\/\/manual.cs50.io\/3\/cexp2f) - base-2 exponent of a complex number\n- [cexp2l](https:\/\/manual.cs50.io\/3\/cexp2l) - base-2 exponent of a complex number\n- [cexpf](https:\/\/manual.cs50.io\/3\/cexpf) - complex exponential function\n- [cexpl](https:\/\/manual.cs50.io\/3\/cexpl) - complex exponential function\n- [cimag](https:\/\/manual.cs50.io\/3\/cimag) - get imaginary part of a complex number\n- [cimagf](https:\/\/manual.cs50.io\/3\/cimagf) - get imaginary part of a complex number\n- [cimagl](https:\/\/manual.cs50.io\/3\/cimagl) - get imaginary part of a complex number\n- [clog](https:\/\/manual.cs50.io\/3\/clog) - natural logarithm of a complex number\n- [clog10](https:\/\/manual.cs50.io\/3\/clog10) - base-10 logarithm of a complex number\n- [clog10f](https:\/\/manual.cs50.io\/3\/clog10f) - base-10 logarithm of a complex number\n- [clog10l](https:\/\/manual.cs50.io\/3\/clog10l) - base-10 logarithm of a complex number\n- [clog2](https:\/\/manual.cs50.io\/3\/clog2) - base-2 logarithm of a complex number\n- [clog2f](https:\/\/manual.cs50.io\/3\/clog2f) - base-2 logarithm of a complex number\n- [clog2l](https:\/\/manual.cs50.io\/3\/clog2l) - base-2 logarithm of a complex number\n- [clogf](https:\/\/manual.cs50.io\/3\/clogf) - natural logarithm of a complex number\n- [clogl](https:\/\/manual.cs50.io\/3\/clogl) - natural logarithm of a complex number\n- [complex](https:\/\/manual.cs50.io\/7\/complex) - basics of complex mathematics\n- [conj](https:\/\/manual.cs50.io\/3\/conj) - calculate the complex conjugate\n- [conjf](https:\/\/manual.cs50.io\/3\/conjf) - calculate the complex conjugate\n- [conjl](https:\/\/manual.cs50.io\/3\/conjl) - calculate the complex conjugate\n- [cpow](https:\/\/manual.cs50.io\/3\/cpow) - complex power function\n- [cpowf](https:\/\/manual.cs50.io\/3\/cpowf) - complex power function\n- [cpowl](https:\/\/manual.cs50.io\/3\/cpowl) - complex power function\n- [cproj](https:\/\/manual.cs50.io\/3\/cproj) - project into Riemann Sphere\n- [cprojf](https:\/\/manual.cs50.io\/3\/cprojf) - project into Riemann Sphere\n- [cprojl](https:\/\/manual.cs50.io\/3\/cprojl) - project into Riemann Sphere\n- [creal](https:\/\/manual.cs50.io\/3\/creal) - get real part of a complex number\n- [crealf](https:\/\/manual.cs50.io\/3\/crealf) - get real part of a complex number\n- [creall](https:\/\/manual.cs50.io\/3\/creall) - get real part of a complex number\n- [csin](https:\/\/manual.cs50.io\/3\/csin) - complex sine function\n- [csinf](https:\/\/manual.cs50.io\/3\/csinf) - complex sine function\n- [csinh](https:\/\/manual.cs50.io\/3\/csinh) - complex hyperbolic sine\n- [csinhf](https:\/\/manual.cs50.io\/3\/csinhf) - complex hyperbolic sine\n- [csinhl](https:\/\/manual.cs50.io\/3\/csinhl) - complex hyperbolic sine\n- [csinl](https:\/\/manual.cs50.io\/3\/csinl) - complex sine function\n- [csqrt](https:\/\/manual.cs50.io\/3\/csqrt) - complex square root\n- [csqrtf](https:\/\/manual.cs50.io\/3\/csqrtf) - complex square root\n- [csqrtl](https:\/\/manual.cs50.io\/3\/csqrtl) - complex square root\n- [ctan](https:\/\/manual.cs50.io\/3\/ctan) - complex tangent function\n- [ctanf](https:\/\/manual.cs50.io\/3\/ctanf) - complex tangent function\n- [ctanh](https:\/\/manual.cs50.io\/3\/ctanh) - complex hyperbolic tangent\n- [ctanhf](https:\/\/manual.cs50.io\/3\/ctanhf) - complex hyperbolic tangent\n- [ctanhl](https:\/\/manual.cs50.io\/3\/ctanhl) - complex hyperbolic tangent\n- [ctanl](https:\/\/manual.cs50.io\/3\/ctanl) - complex tangent function\n\n- [get\\_char](https:\/\/manual.cs50.io\/3\/get_char) - prompts user for a line of text from stdin and returns... prompt a user for a `char`\n- [get\\_double](https:\/\/manual.cs50.io\/3\/get_double) - prompts user for a line of text from stdin and returns... prompt a user for a `double`\n- [get\\_float](https:\/\/manual.cs50.io\/3\/get_float) - prompts user for a line of text from stdin and returns... prompt a user for a `float`\n- [get\\_int](https:\/\/manual.cs50.io\/3\/get_int) - prompts user for a line of text from stdin and returns... prompt a user for an `int`\n- [get\\_long](https:\/\/manual.cs50.io\/3\/get_long) - prompts user for a line of text from stdin and returns... prompt a user for an `long`\n- [get\\_long\\_long](https:\/\/manual.cs50.io\/3\/get_long_long) - prompts user for a line of text from stdin and returns...\n- [get\\_string](https:\/\/manual.cs50.io\/3\/get_string) - prompts user for a line of text from stdin and returns... prompt a user for a `string`\n## [ctype.h](https:\/\/manual.cs50.io\/#ctype.h)\n- [isalnum](https:\/\/manual.cs50.io\/3\/isalnum) - character classification functions check whether a character is alphanumeric\n- [isalnum\\_l](https:\/\/manual.cs50.io\/3\/isalnum_l) - character classification functions\n- [isalpha](https:\/\/manual.cs50.io\/3\/isalpha) - character classification functions check whether a character is alphabetical\n- [isalpha\\_l](https:\/\/manual.cs50.io\/3\/isalpha_l) - character classification functions\n- [isascii](https:\/\/manual.cs50.io\/3\/isascii) - character classification functions\n- [isascii\\_l](https:\/\/manual.cs50.io\/3\/isascii_l) - character classification functions\n- [isblank](https:\/\/manual.cs50.io\/3\/isblank) - character classification functions check whether a character is blank (i.e., a space or tab)\n- [isblank\\_l](https:\/\/manual.cs50.io\/3\/isblank_l) - character classification functions\n- [iscntrl](https:\/\/manual.cs50.io\/3\/iscntrl) - character classification functions\n- [iscntrl\\_l](https:\/\/manual.cs50.io\/3\/iscntrl_l) - character classification functions\n- [isdigit](https:\/\/manual.cs50.io\/3\/isdigit) - character classification functions check whether a character is a digit\n- [isdigit\\_l](https:\/\/manual.cs50.io\/3\/isdigit_l) - character classification functions\n- [isgraph](https:\/\/manual.cs50.io\/3\/isgraph) - character classification functions\n- [isgraph\\_l](https:\/\/manual.cs50.io\/3\/isgraph_l) - character classification functions\n- [islower](https:\/\/manual.cs50.io\/3\/islower) - character classification functions check whether a character is lowercase\n- [islower\\_l](https:\/\/manual.cs50.io\/3\/islower_l) - character classification functions\n- [isprint](https:\/\/manual.cs50.io\/3\/isprint) - character classification functions\n- [isprint\\_l](https:\/\/manual.cs50.io\/3\/isprint_l) - character classification functions\n- [ispunct](https:\/\/manual.cs50.io\/3\/ispunct) - character classification functions check whether a character is punctuation\n- [ispunct\\_l](https:\/\/manual.cs50.io\/3\/ispunct_l) - character classification functions\n- [isspace](https:\/\/manual.cs50.io\/3\/isspace) - character classification functions check whether a character is whitespace (e.g., a newline, space, or tab)\n- [isspace\\_l](https:\/\/manual.cs50.io\/3\/isspace_l) - character classification functions\n- [isupper](https:\/\/manual.cs50.io\/3\/isupper) - character classification functions check whether a character is uppercase\n- [isupper\\_l](https:\/\/manual.cs50.io\/3\/isupper_l) - character classification functions\n- [isxdigit](https:\/\/manual.cs50.io\/3\/isxdigit) - character classification functions\n- [isxdigit\\_l](https:\/\/manual.cs50.io\/3\/isxdigit_l) - character classification functions\n- [toascii](https:\/\/manual.cs50.io\/3\/toascii) - convert character to ASCII\n- [tolower](https:\/\/manual.cs50.io\/3\/tolower) - convert uppercase or lowercase convert a `char` to lowercase\n- [tolower\\_l](https:\/\/manual.cs50.io\/3\/tolower_l) - convert uppercase or lowercase\n- [toupper](https:\/\/manual.cs50.io\/3\/toupper) - convert uppercase or lowercase convert a `char` to uppercase\n- [toupper\\_l](https:\/\/manual.cs50.io\/3\/toupper_l) - convert uppercase or lowercase\n## [dirent.h](https:\/\/manual.cs50.io\/#dirent.h)\n- [alphasort](https:\/\/manual.cs50.io\/3\/alphasort) - scan a directory for matching entries\n- [getdirentries](https:\/\/manual.cs50.io\/3\/getdirentries) - get directory entries in a filesystem-independent format\n- [readdir](https:\/\/manual.cs50.io\/3\/readdir) - read a directory\n- [readdir\\_r](https:\/\/manual.cs50.io\/3\/readdir_r) - read a directory\n- [scandir](https:\/\/manual.cs50.io\/3\/scandir) - scan a directory for matching entries\n- [scandirat](https:\/\/manual.cs50.io\/3\/scandirat) - scan a directory for matching entries\n- [seekdir](https:\/\/manual.cs50.io\/3\/seekdir) - set the position of the next readdir() call in the dir...\n- [telldir](https:\/\/manual.cs50.io\/3\/telldir) - return current location in directory stream\n- [versionsort](https:\/\/manual.cs50.io\/3\/versionsort) - scan a directory for matching entries\n## [dlfcn.h](https:\/\/manual.cs50.io\/#dlfcn.h)\n- [dladdr](https:\/\/manual.cs50.io\/3\/dladdr) - translate address to symbolic information\n- [dladdr1](https:\/\/manual.cs50.io\/3\/dladdr1) - translate address to symbolic information\n- [dlclose](https:\/\/manual.cs50.io\/3\/dlclose) - open and close a shared object\n- [dlerror](https:\/\/manual.cs50.io\/3\/dlerror) - obtain error diagnostic for functions in the dlopen API\n- [dlmopen](https:\/\/manual.cs50.io\/3\/dlmopen) - open and close a shared object\n- [dlopen](https:\/\/manual.cs50.io\/3\/dlopen) - open and close a shared object\n- [dlsym](https:\/\/manual.cs50.io\/3\/dlsym) - obtain address of a symbol in a shared object or execu...\n- [dlvsym](https:\/\/manual.cs50.io\/3\/dlvsym) - obtain address of a symbol in a shared object or execu...\n## [errno.h](https:\/\/manual.cs50.io\/#errno.h)\n- [errno](https:\/\/manual.cs50.io\/3\/errno) - number of last error\n- [program\\_invocation\\_name](https:\/\/manual.cs50.io\/3\/program_invocation_name) - obtain name used to invoke calling program\n- [program\\_invocation\\_short\\_name](https:\/\/manual.cs50.io\/3\/program_invocation_short_name) - obtain name used to invoke calling program\n## [fcntl.h](https:\/\/manual.cs50.io\/#fcntl.h)\n- [arm\\_fadvise](https:\/\/manual.cs50.io\/2\/arm_fadvise) - predeclare an access pattern for file data\n- [arm\\_fadvise64\\_64](https:\/\/manual.cs50.io\/2\/arm_fadvise64_64) - predeclare an access pattern for file data\n- [arm\\_sync\\_file\\_range](https:\/\/manual.cs50.io\/2\/arm_sync_file_range) - sync a file segment with disk\n- [creat](https:\/\/manual.cs50.io\/2\/creat) - open and possibly create a file\n- [fadvise64](https:\/\/manual.cs50.io\/2\/fadvise64) - predeclare an access pattern for file data\n- [fadvise64\\_64](https:\/\/manual.cs50.io\/2\/fadvise64_64) - predeclare an access pattern for file data\n- [fallocate](https:\/\/manual.cs50.io\/2\/fallocate) - manipulate file space\n- [fcntl](https:\/\/manual.cs50.io\/2\/fcntl) - manipulate file descriptor\n- [fcntl64](https:\/\/manual.cs50.io\/2\/fcntl64) - manipulate file descriptor\n- [name\\_to\\_handle\\_at](https:\/\/manual.cs50.io\/2\/name_to_handle_at) - obtain handle for a pathname and open file via a handle\n- [open](https:\/\/manual.cs50.io\/2\/open) - open and possibly create a file\n- [open\\_by\\_handle\\_at](https:\/\/manual.cs50.io\/2\/open_by_handle_at) - obtain handle for a pathname and open file via a handle\n- [openat](https:\/\/manual.cs50.io\/2\/openat) - open and possibly create a file\n- [posix\\_fadvise](https:\/\/manual.cs50.io\/2\/posix_fadvise) - predeclare an access pattern for file data\n- [posix\\_fallocate](https:\/\/manual.cs50.io\/3\/posix_fallocate) - allocate file space\n- [readahead](https:\/\/manual.cs50.io\/2\/readahead) - initiate file readahead into page cache\n- [splice](https:\/\/manual.cs50.io\/2\/splice) - splice data to\/from a pipe\n- [sync\\_file\\_range](https:\/\/manual.cs50.io\/2\/sync_file_range) - sync a file segment with disk\n- [sync\\_file\\_range2](https:\/\/manual.cs50.io\/2\/sync_file_range2) - sync a file segment with disk\n- [tee](https:\/\/manual.cs50.io\/2\/tee) - duplicating pipe content\n- [vmsplice](https:\/\/manual.cs50.io\/2\/vmsplice) - splice user pages to\/from a pipe\n## [fenv.h](https:\/\/manual.cs50.io\/#fenv.h)\n- [feclearexcept](https:\/\/manual.cs50.io\/3\/feclearexcept) - floating-point rounding and exception handling\n- [fedisableexcept](https:\/\/manual.cs50.io\/3\/fedisableexcept) - floating-point rounding and exception handling\n- [feenableexcept](https:\/\/manual.cs50.io\/3\/feenableexcept) - floating-point rounding and exception handling\n- [fegetenv](https:\/\/manual.cs50.io\/3\/fegetenv) - floating-point rounding and exception handling\n- [fegetexcept](https:\/\/manual.cs50.io\/3\/fegetexcept) - floating-point rounding and exception handling\n- [fegetexceptflag](https:\/\/manual.cs50.io\/3\/fegetexceptflag) - floating-point rounding and exception handling\n- [fegetround](https:\/\/manual.cs50.io\/3\/fegetround) - floating-point rounding and exception handling\n- [feholdexcept](https:\/\/manual.cs50.io\/3\/feholdexcept) - floating-point rounding and exception handling\n- [fenv](https:\/\/manual.cs50.io\/3\/fenv) - floating-point rounding and exception handling\n- [feraiseexcept](https:\/\/manual.cs50.io\/3\/feraiseexcept) - floating-point rounding and exception handling\n- [fesetenv](https:\/\/manual.cs50.io\/3\/fesetenv) - floating-point rounding and exception handling\n- [fesetexceptflag](https:\/\/manual.cs50.io\/3\/fesetexceptflag) - floating-point rounding and exception handling\n- [fesetround](https:\/\/manual.cs50.io\/3\/fesetround) - floating-point rounding and exception handling\n- [fetestexcept](https:\/\/manual.cs50.io\/3\/fetestexcept) - floating-point rounding and exception handling\n- [feupdateenv](https:\/\/manual.cs50.io\/3\/feupdateenv) - floating-point rounding and exception handling\n## [fmtmsg.h](https:\/\/manual.cs50.io\/#fmtmsg.h)\n- [addseverity](https:\/\/manual.cs50.io\/3\/addseverity) - introduce new severity classes\n- [fmtmsg](https:\/\/manual.cs50.io\/3\/fmtmsg) - print formatted error messages\n## [fnmatch.h](https:\/\/manual.cs50.io\/#fnmatch.h)\n- [fnmatch](https:\/\/manual.cs50.io\/3\/fnmatch) - match filename or pathname\n## [ftw.h](https:\/\/manual.cs50.io\/#ftw.h)\n- [ftw](https:\/\/manual.cs50.io\/3\/ftw) - file tree walk\n- [nftw](https:\/\/manual.cs50.io\/3\/nftw) - file tree walk\n## [glob.h](https:\/\/manual.cs50.io\/#glob.h)\n- [glob](https:\/\/manual.cs50.io\/3\/glob) - find pathnames matching a pattern, free memory from gl...\n- [globfree](https:\/\/manual.cs50.io\/3\/globfree) - find pathnames matching a pattern, free memory from gl...\n## [grp.h](https:\/\/manual.cs50.io\/#grp.h)\n- [fgetgrent\\_r](https:\/\/manual.cs50.io\/3\/fgetgrent_r) - get group file entry reentrantly\n- [getgrent\\_r](https:\/\/manual.cs50.io\/3\/getgrent_r) - get group file entry reentrantly\n- [getgrouplist](https:\/\/manual.cs50.io\/3\/getgrouplist) - get list of groups to which a user belongs\n- [putgrent](https:\/\/manual.cs50.io\/3\/putgrent) - write a group database entry to a file\n## [iconv.h](https:\/\/manual.cs50.io\/#iconv.h)\n- [iconv](https:\/\/manual.cs50.io\/3\/iconv) - perform character set conversion\n- [iconv\\_close](https:\/\/manual.cs50.io\/3\/iconv_close) - deallocate descriptor for character set conversion\n- [iconv\\_open](https:\/\/manual.cs50.io\/3\/iconv_open) - allocate descriptor for character set conversion\n## [inttypes.h](https:\/\/manual.cs50.io\/#inttypes.h)\n- [strtoimax](https:\/\/manual.cs50.io\/3\/strtoimax) - convert string to integer\n- [strtoumax](https:\/\/manual.cs50.io\/3\/strtoumax) - convert string to integer\n## [langinfo.h](https:\/\/manual.cs50.io\/#langinfo.h)\n- [nl\\_langinfo](https:\/\/manual.cs50.io\/3\/nl_langinfo) - query language and locale information\n- [nl\\_langinfo\\_l](https:\/\/manual.cs50.io\/3\/nl_langinfo_l) - query language and locale information\n## [libgen.h](https:\/\/manual.cs50.io\/#libgen.h)\n- [basename](https:\/\/manual.cs50.io\/3\/basename) - parse pathname components\n- [dirname](https:\/\/manual.cs50.io\/3\/dirname) - parse pathname components\n## [limits.h](https:\/\/manual.cs50.io\/#limits.h)\n- [MB\\_LEN\\_MAX](https:\/\/manual.cs50.io\/3\/MB_LEN_MAX) - maximum multibyte length of a character across all loc...\n- [realpath](https:\/\/manual.cs50.io\/3\/realpath) - return the canonicalized absolute pathname\n## [locale.h](https:\/\/manual.cs50.io\/#locale.h)\n- [duplocale](https:\/\/manual.cs50.io\/3\/duplocale) - duplicate a locale object\n- [freelocale](https:\/\/manual.cs50.io\/3\/freelocale) - create, modify, and free a locale object\n- [locale](https:\/\/manual.cs50.io\/7\/locale) - description of multilanguage support\n- [localeconv](https:\/\/manual.cs50.io\/3\/localeconv) - get numeric formatting information\n- [newlocale](https:\/\/manual.cs50.io\/3\/newlocale) - create, modify, and free a locale object\n- [setlocale](https:\/\/manual.cs50.io\/3\/setlocale) - set the current locale\n- [uselocale](https:\/\/manual.cs50.io\/3\/uselocale) - set\/get the locale for the calling thread\n## [math.h](https:\/\/manual.cs50.io\/#math.h)\n- [acos](https:\/\/manual.cs50.io\/3\/acos) - arc cosine function\n- [acosf](https:\/\/manual.cs50.io\/3\/acosf) - arc cosine function\n- [acosh](https:\/\/manual.cs50.io\/3\/acosh) - inverse hyperbolic cosine function\n- [acoshf](https:\/\/manual.cs50.io\/3\/acoshf) - inverse hyperbolic cosine function\n- [acoshl](https:\/\/manual.cs50.io\/3\/acoshl) - inverse hyperbolic cosine function\n- [acosl](https:\/\/manual.cs50.io\/3\/acosl) - arc cosine function\n- [asin](https:\/\/manual.cs50.io\/3\/asin) - arc sine function\n- [asinf](https:\/\/manual.cs50.io\/3\/asinf) - arc sine function\n- [asinh](https:\/\/manual.cs50.io\/3\/asinh) - inverse hyperbolic sine function\n- [asinhf](https:\/\/manual.cs50.io\/3\/asinhf) - inverse hyperbolic sine function\n- [asinhl](https:\/\/manual.cs50.io\/3\/asinhl) - inverse hyperbolic sine function\n- [asinl](https:\/\/manual.cs50.io\/3\/asinl) - arc sine function\n- [atan](https:\/\/manual.cs50.io\/3\/atan) - arc tangent function\n- [atan2](https:\/\/manual.cs50.io\/3\/atan2) - arc tangent function of two variables\n- [atan2f](https:\/\/manual.cs50.io\/3\/atan2f) - arc tangent function of two variables\n- [atan2l](https:\/\/manual.cs50.io\/3\/atan2l) - arc tangent function of two variables\n- [atanf](https:\/\/manual.cs50.io\/3\/atanf) - arc tangent function\n- [atanh](https:\/\/manual.cs50.io\/3\/atanh) - inverse hyperbolic tangent function\n- [atanhf](https:\/\/manual.cs50.io\/3\/atanhf) - inverse hyperbolic tangent function\n- [atanhl](https:\/\/manual.cs50.io\/3\/atanhl) - inverse hyperbolic tangent function\n- [atanl](https:\/\/manual.cs50.io\/3\/atanl) - arc tangent function\n- [cbrt](https:\/\/manual.cs50.io\/3\/cbrt) - cube root function\n- [cbrtf](https:\/\/manual.cs50.io\/3\/cbrtf) - cube root function\n- [cbrtl](https:\/\/manual.cs50.io\/3\/cbrtl) - cube root function\n- [ceil](https:\/\/manual.cs50.io\/3\/ceil) - ceiling function: smallest integral value not less tha... calculate the ceiling of a number\n- [ceilf](https:\/\/manual.cs50.io\/3\/ceilf) - ceiling function: smallest integral value not less tha...\n- [ceill](https:\/\/manual.cs50.io\/3\/ceill) - ceiling function: smallest integral value not less tha...\n- [copysign](https:\/\/manual.cs50.io\/3\/copysign) - copy sign of a number\n- [copysignf](https:\/\/manual.cs50.io\/3\/copysignf) - copy sign of a number\n- [copysignl](https:\/\/manual.cs50.io\/3\/copysignl) - copy sign of a number\n- [cos](https:\/\/manual.cs50.io\/3\/cos) - cosine function\n- [cosf](https:\/\/manual.cs50.io\/3\/cosf) - cosine function\n- [cosh](https:\/\/manual.cs50.io\/3\/cosh) - hyperbolic cosine function\n- [coshf](https:\/\/manual.cs50.io\/3\/coshf) - hyperbolic cosine function\n- [coshl](https:\/\/manual.cs50.io\/3\/coshl) - hyperbolic cosine function\n- [cosl](https:\/\/manual.cs50.io\/3\/cosl) - cosine function\n- [drem](https:\/\/manual.cs50.io\/3\/drem) - floating-point remainder function\n- [dremf](https:\/\/manual.cs50.io\/3\/dremf) - floating-point remainder function\n- [dreml](https:\/\/manual.cs50.io\/3\/dreml) - floating-point remainder function\n- [erf](https:\/\/manual.cs50.io\/3\/erf) - error function\n- [erfc](https:\/\/manual.cs50.io\/3\/erfc) - complementary error function\n- [erfcf](https:\/\/manual.cs50.io\/3\/erfcf) - complementary error function\n- [erfcl](https:\/\/manual.cs50.io\/3\/erfcl) - complementary error function\n- [erff](https:\/\/manual.cs50.io\/3\/erff) - error function\n- [erfl](https:\/\/manual.cs50.io\/3\/erfl) - error function\n- [exp](https:\/\/manual.cs50.io\/3\/exp) - base-e exponential function\n- [exp10](https:\/\/manual.cs50.io\/3\/exp10) - base-10 exponential function\n- [exp10f](https:\/\/manual.cs50.io\/3\/exp10f) - base-10 exponential function\n- [exp10l](https:\/\/manual.cs50.io\/3\/exp10l) - base-10 exponential function\n- [exp2](https:\/\/manual.cs50.io\/3\/exp2) - base-2 exponential function\n- [exp2f](https:\/\/manual.cs50.io\/3\/exp2f) - base-2 exponential function\n- [exp2l](https:\/\/manual.cs50.io\/3\/exp2l) - base-2 exponential function\n- [expf](https:\/\/manual.cs50.io\/3\/expf) - base-e exponential function\n- [expl](https:\/\/manual.cs50.io\/3\/expl) - base-e exponential function\n- [expm1](https:\/\/manual.cs50.io\/3\/expm1) - exponential minus 1\n- [expm1f](https:\/\/manual.cs50.io\/3\/expm1f) - exponential minus 1\n- [expm1l](https:\/\/manual.cs50.io\/3\/expm1l) - exponential minus 1\n- [fabs](https:\/\/manual.cs50.io\/3\/fabs) - absolute value of floating-point number\n- [fabsf](https:\/\/manual.cs50.io\/3\/fabsf) - absolute value of floating-point number\n- [fabsl](https:\/\/manual.cs50.io\/3\/fabsl) - absolute value of floating-point number\n- [fdim](https:\/\/manual.cs50.io\/3\/fdim) - positive difference\n- [fdimf](https:\/\/manual.cs50.io\/3\/fdimf) - positive difference\n- [fdiml](https:\/\/manual.cs50.io\/3\/fdiml) - positive difference\n- [finite](https:\/\/manual.cs50.io\/3\/finite) - BSD floating-point classification functions\n- [finitef](https:\/\/manual.cs50.io\/3\/finitef) - BSD floating-point classification functions\n- [finitel](https:\/\/manual.cs50.io\/3\/finitel) - BSD floating-point classification functions\n- [floor](https:\/\/manual.cs50.io\/3\/floor) - largest integral value not greater than argument calculate the floor of a number\n- [floorf](https:\/\/manual.cs50.io\/3\/floorf) - largest integral value not greater than argument\n- [floorl](https:\/\/manual.cs50.io\/3\/floorl) - largest integral value not greater than argument\n- [fma](https:\/\/manual.cs50.io\/3\/fma) - floating-point multiply and add\n- [fmaf](https:\/\/manual.cs50.io\/3\/fmaf) - floating-point multiply and add\n- [fmal](https:\/\/manual.cs50.io\/3\/fmal) - floating-point multiply and add\n- [fmax](https:\/\/manual.cs50.io\/3\/fmax) - determine maximum of two floating-point numbers\n- [fmaxf](https:\/\/manual.cs50.io\/3\/fmaxf) - determine maximum of two floating-point numbers\n- [fmaxl](https:\/\/manual.cs50.io\/3\/fmaxl) - determine maximum of two floating-point numbers\n- [fmin](https:\/\/manual.cs50.io\/3\/fmin) - determine minimum of two floating-point numbers\n- [fminf](https:\/\/manual.cs50.io\/3\/fminf) - determine minimum of two floating-point numbers\n- [fminl](https:\/\/manual.cs50.io\/3\/fminl) - determine minimum of two floating-point numbers\n- [fmod](https:\/\/manual.cs50.io\/3\/fmod) - floating-point remainder function\n- [fmodf](https:\/\/manual.cs50.io\/3\/fmodf) - floating-point remainder function\n- [fmodl](https:\/\/manual.cs50.io\/3\/fmodl) - floating-point remainder function\n- [fpclassify](https:\/\/manual.cs50.io\/3\/fpclassify) - floating-point classification macros\n- [frexp](https:\/\/manual.cs50.io\/3\/frexp) - convert floating-point number to fractional and integr...\n- [frexpf](https:\/\/manual.cs50.io\/3\/frexpf) - convert floating-point number to fractional and integr...\n- [frexpl](https:\/\/manual.cs50.io\/3\/frexpl) - convert floating-point number to fractional and integr...\n- [gamma](https:\/\/manual.cs50.io\/3\/gamma) - (logarithm of the) gamma function\n- [gammaf](https:\/\/manual.cs50.io\/3\/gammaf) - (logarithm of the) gamma function\n- [gammal](https:\/\/manual.cs50.io\/3\/gammal) - (logarithm of the) gamma function\n- [HUGE\\_VAL](https:\/\/manual.cs50.io\/3\/HUGE_VAL) - floating-point constants\n- [HUGE\\_VALF](https:\/\/manual.cs50.io\/3\/HUGE_VALF) - floating-point constants\n- [HUGE\\_VALL](https:\/\/manual.cs50.io\/3\/HUGE_VALL) - floating-point constants\n- [hypot](https:\/\/manual.cs50.io\/3\/hypot) - Euclidean distance function\n- [hypotf](https:\/\/manual.cs50.io\/3\/hypotf) - Euclidean distance function\n- [hypotl](https:\/\/manual.cs50.io\/3\/hypotl) - Euclidean distance function\n- [ilogb](https:\/\/manual.cs50.io\/3\/ilogb) - get integer exponent of a floating-point value\n- [ilogbf](https:\/\/manual.cs50.io\/3\/ilogbf) - get integer exponent of a floating-point value\n- [ilogbl](https:\/\/manual.cs50.io\/3\/ilogbl) - get integer exponent of a floating-point value\n- [INFINITY](https:\/\/manual.cs50.io\/3\/INFINITY) - floating-point constants\n- [isfinite](https:\/\/manual.cs50.io\/3\/isfinite) - floating-point classification macros\n- [isgreater](https:\/\/manual.cs50.io\/3\/isgreater) - floating-point relational tests without exception for NaN\n- [isgreaterequal](https:\/\/manual.cs50.io\/3\/isgreaterequal) - floating-point relational tests without exception for NaN\n- [isinf](https:\/\/manual.cs50.io\/3\/isinf) - floating-point classification macros\n- [isinff](https:\/\/manual.cs50.io\/3\/isinff) - BSD floating-point classification functions\n- [isinfl](https:\/\/manual.cs50.io\/3\/isinfl) - BSD floating-point classification functions\n- [isless](https:\/\/manual.cs50.io\/3\/isless) - floating-point relational tests without exception for NaN\n- [islessequal](https:\/\/manual.cs50.io\/3\/islessequal) - floating-point relational tests without exception for NaN\n- [islessgreater](https:\/\/manual.cs50.io\/3\/islessgreater) - floating-point relational tests without exception for NaN\n- [isnan](https:\/\/manual.cs50.io\/3\/isnan) - floating-point classification macros\n- [isnanf](https:\/\/manual.cs50.io\/3\/isnanf) - BSD floating-point classification functions\n- [isnanl](https:\/\/manual.cs50.io\/3\/isnanl) - BSD floating-point classification functions\n- [isnormal](https:\/\/manual.cs50.io\/3\/isnormal) - floating-point classification macros\n- [isunordered](https:\/\/manual.cs50.io\/3\/isunordered) - floating-point relational tests without exception for NaN\n- [j0](https:\/\/manual.cs50.io\/3\/j0) - Bessel functions of the first kind\n- [j0f](https:\/\/manual.cs50.io\/3\/j0f) - Bessel functions of the first kind\n- [j0l](https:\/\/manual.cs50.io\/3\/j0l) - Bessel functions of the first kind\n- [j1](https:\/\/manual.cs50.io\/3\/j1) - Bessel functions of the first kind\n- [j1f](https:\/\/manual.cs50.io\/3\/j1f) - Bessel functions of the first kind\n- [j1l](https:\/\/manual.cs50.io\/3\/j1l) - Bessel functions of the first kind\n- [jn](https:\/\/manual.cs50.io\/3\/jn) - Bessel functions of the first kind\n- [jnf](https:\/\/manual.cs50.io\/3\/jnf) - Bessel functions of the first kind\n- [jnl](https:\/\/manual.cs50.io\/3\/jnl) - Bessel functions of the first kind\n- [ldexp](https:\/\/manual.cs50.io\/3\/ldexp) - multiply floating-point number by integral power of 2\n- [ldexpf](https:\/\/manual.cs50.io\/3\/ldexpf) - multiply floating-point number by integral power of 2\n- [ldexpl](https:\/\/manual.cs50.io\/3\/ldexpl) - multiply floating-point number by integral power of 2\n- [lgamma](https:\/\/manual.cs50.io\/3\/lgamma) - log gamma function\n- [lgamma\\_r](https:\/\/manual.cs50.io\/3\/lgamma_r) - log gamma function\n- [lgammaf](https:\/\/manual.cs50.io\/3\/lgammaf) - log gamma function\n- [lgammaf\\_r](https:\/\/manual.cs50.io\/3\/lgammaf_r) - log gamma function\n- [lgammal](https:\/\/manual.cs50.io\/3\/lgammal) - log gamma function\n- [lgammal\\_r](https:\/\/manual.cs50.io\/3\/lgammal_r) - log gamma function\n- [llrint](https:\/\/manual.cs50.io\/3\/llrint) - round to nearest integer\n- [llrintf](https:\/\/manual.cs50.io\/3\/llrintf) - round to nearest integer\n- [llrintl](https:\/\/manual.cs50.io\/3\/llrintl) - round to nearest integer\n- [llround](https:\/\/manual.cs50.io\/3\/llround) - round to nearest integer\n- [llroundf](https:\/\/manual.cs50.io\/3\/llroundf) - round to nearest integer\n- [llroundl](https:\/\/manual.cs50.io\/3\/llroundl) - round to nearest integer\n- [log](https:\/\/manual.cs50.io\/3\/log) - natural logarithmic function\n- [log10](https:\/\/manual.cs50.io\/3\/log10) - base-10 logarithmic function\n- [log10f](https:\/\/manual.cs50.io\/3\/log10f) - base-10 logarithmic function\n- [log10l](https:\/\/manual.cs50.io\/3\/log10l) - base-10 logarithmic function\n- [log1p](https:\/\/manual.cs50.io\/3\/log1p) - logarithm of 1 plus argument\n- [log1pf](https:\/\/manual.cs50.io\/3\/log1pf) - logarithm of 1 plus argument\n- [log1pl](https:\/\/manual.cs50.io\/3\/log1pl) - logarithm of 1 plus argument\n- [log2](https:\/\/manual.cs50.io\/3\/log2) - base-2 logarithmic function calculate the base-2 logarithm of a number\n- [log2f](https:\/\/manual.cs50.io\/3\/log2f) - base-2 logarithmic function\n- [log2l](https:\/\/manual.cs50.io\/3\/log2l) - base-2 logarithmic function\n- [logb](https:\/\/manual.cs50.io\/3\/logb) - get exponent of a floating-point value\n- [logbf](https:\/\/manual.cs50.io\/3\/logbf) - get exponent of a floating-point value\n- [logbl](https:\/\/manual.cs50.io\/3\/logbl) - get exponent of a floating-point value\n- [logf](https:\/\/manual.cs50.io\/3\/logf) - natural logarithmic function\n- [logl](https:\/\/manual.cs50.io\/3\/logl) - natural logarithmic function\n- [lrint](https:\/\/manual.cs50.io\/3\/lrint) - round to nearest integer\n- [lrintf](https:\/\/manual.cs50.io\/3\/lrintf) - round to nearest integer\n- [lrintl](https:\/\/manual.cs50.io\/3\/lrintl) - round to nearest integer\n- [lround](https:\/\/manual.cs50.io\/3\/lround) - round to nearest integer\n- [lroundf](https:\/\/manual.cs50.io\/3\/lroundf) - round to nearest integer\n- [lroundl](https:\/\/manual.cs50.io\/3\/lroundl) - round to nearest integer\n- [math\\_error](https:\/\/manual.cs50.io\/7\/math_error) - detecting errors from mathematical functions\n- [matherr](https:\/\/manual.cs50.io\/3\/matherr) - SVID math library exception handling\n- [modf](https:\/\/manual.cs50.io\/3\/modf) - extract signed integral and fractional values from flo...\n- [modff](https:\/\/manual.cs50.io\/3\/modff) - extract signed integral and fractional values from flo...\n- [modfl](https:\/\/manual.cs50.io\/3\/modfl) - extract signed integral and fractional values from flo...\n- [NAN](https:\/\/manual.cs50.io\/3\/NAN) - floating-point constants\n- [nan](https:\/\/manual.cs50.io\/3\/nan) - return 'Not a Number'\n- [nanf](https:\/\/manual.cs50.io\/3\/nanf) - return 'Not a Number'\n- [nanl](https:\/\/manual.cs50.io\/3\/nanl) - return 'Not a Number'\n- [nearbyint](https:\/\/manual.cs50.io\/3\/nearbyint) - round to nearest integer\n- [nearbyintf](https:\/\/manual.cs50.io\/3\/nearbyintf) - round to nearest integer\n- [nearbyintl](https:\/\/manual.cs50.io\/3\/nearbyintl) - round to nearest integer\n- [nextafter](https:\/\/manual.cs50.io\/3\/nextafter) - floating-point number manipulation\n- [nextafterf](https:\/\/manual.cs50.io\/3\/nextafterf) - floating-point number manipulation\n- [nextafterl](https:\/\/manual.cs50.io\/3\/nextafterl) - floating-point number manipulation\n- [nextdown](https:\/\/manual.cs50.io\/3\/nextdown) - return next floating-point number toward positive\/nega...\n- [nextdownf](https:\/\/manual.cs50.io\/3\/nextdownf) - return next floating-point number toward positive\/nega...\n- [nextdownl](https:\/\/manual.cs50.io\/3\/nextdownl) - return next floating-point number toward positive\/nega...\n- [nexttoward](https:\/\/manual.cs50.io\/3\/nexttoward) - floating-point number manipulation\n- [nexttowardf](https:\/\/manual.cs50.io\/3\/nexttowardf) - floating-point number manipulation\n- [nexttowardl](https:\/\/manual.cs50.io\/3\/nexttowardl) - floating-point number manipulation\n- [nextup](https:\/\/manual.cs50.io\/3\/nextup) - return next floating-point number toward positive\/nega...\n- [nextupf](https:\/\/manual.cs50.io\/3\/nextupf) - return next floating-point number toward positive\/nega...\n- [nextupl](https:\/\/manual.cs50.io\/3\/nextupl) - return next floating-point number toward positive\/nega...\n- [pow](https:\/\/manual.cs50.io\/3\/pow) - power functions raise a number to a power\n- [pow10](https:\/\/manual.cs50.io\/3\/pow10) - base-10 power functions\n- [pow10f](https:\/\/manual.cs50.io\/3\/pow10f) - base-10 power functions\n- [pow10l](https:\/\/manual.cs50.io\/3\/pow10l) - base-10 power functions\n- [powf](https:\/\/manual.cs50.io\/3\/powf) - power functions\n- [powl](https:\/\/manual.cs50.io\/3\/powl) - power functions\n- [remainder](https:\/\/manual.cs50.io\/3\/remainder) - floating-point remainder function\n- [remainderf](https:\/\/manual.cs50.io\/3\/remainderf) - floating-point remainder function\n- [remainderl](https:\/\/manual.cs50.io\/3\/remainderl) - floating-point remainder function\n- [remquo](https:\/\/manual.cs50.io\/3\/remquo) - remainder and part of quotient\n- [remquof](https:\/\/manual.cs50.io\/3\/remquof) - remainder and part of quotient\n- [remquol](https:\/\/manual.cs50.io\/3\/remquol) - remainder and part of quotient\n- [rint](https:\/\/manual.cs50.io\/3\/rint) - round to nearest integer\n- [rintf](https:\/\/manual.cs50.io\/3\/rintf) - round to nearest integer\n- [rintl](https:\/\/manual.cs50.io\/3\/rintl) - round to nearest integer\n- [round](https:\/\/manual.cs50.io\/3\/round) - round to nearest integer, away from zero round a number to the nearest integer\n- [roundf](https:\/\/manual.cs50.io\/3\/roundf) - round to nearest integer, away from zero\n- [roundl](https:\/\/manual.cs50.io\/3\/roundl) - round to nearest integer, away from zero\n- [scalb](https:\/\/manual.cs50.io\/3\/scalb) - multiply floating-point number by integral power of ra...\n- [scalbf](https:\/\/manual.cs50.io\/3\/scalbf) - multiply floating-point number by integral power of ra...\n- [scalbl](https:\/\/manual.cs50.io\/3\/scalbl) - multiply floating-point number by integral power of ra...\n- [scalbln](https:\/\/manual.cs50.io\/3\/scalbln) - multiply floating-point number by integral power of radix\n- [scalblnf](https:\/\/manual.cs50.io\/3\/scalblnf) - multiply floating-point number by integral power of radix\n- [scalblnl](https:\/\/manual.cs50.io\/3\/scalblnl) - multiply floating-point number by integral power of radix\n- [scalbn](https:\/\/manual.cs50.io\/3\/scalbn) - multiply floating-point number by integral power of radix\n- [scalbnf](https:\/\/manual.cs50.io\/3\/scalbnf) - multiply floating-point number by integral power of radix\n- [scalbnl](https:\/\/manual.cs50.io\/3\/scalbnl) - multiply floating-point number by integral power of radix\n- [signbit](https:\/\/manual.cs50.io\/3\/signbit) - test sign of a real floating-point number\n- [signgam](https:\/\/manual.cs50.io\/3\/signgam) - log gamma function\n- [significand](https:\/\/manual.cs50.io\/3\/significand) - get mantissa of floating-point number\n- [significandf](https:\/\/manual.cs50.io\/3\/significandf) - get mantissa of floating-point number\n- [significandl](https:\/\/manual.cs50.io\/3\/significandl) - get mantissa of floating-point number\n- [sin](https:\/\/manual.cs50.io\/3\/sin) - sine function\n- [sincos](https:\/\/manual.cs50.io\/3\/sincos) - calculate sin and cos simultaneously\n- [sincosf](https:\/\/manual.cs50.io\/3\/sincosf) - calculate sin and cos simultaneously\n- [sincosl](https:\/\/manual.cs50.io\/3\/sincosl) - calculate sin and cos simultaneously\n- [sinf](https:\/\/manual.cs50.io\/3\/sinf) - sine function\n- [sinh](https:\/\/manual.cs50.io\/3\/sinh) - hyperbolic sine function\n- [sinhf](https:\/\/manual.cs50.io\/3\/sinhf) - hyperbolic sine function\n- [sinhl](https:\/\/manual.cs50.io\/3\/sinhl) - hyperbolic sine function\n- [sinl](https:\/\/manual.cs50.io\/3\/sinl) - sine function\n- [sqrt](https:\/\/manual.cs50.io\/3\/sqrt) - square root function calculate the square root of a number\n- [sqrtf](https:\/\/manual.cs50.io\/3\/sqrtf) - square root function\n- [sqrtl](https:\/\/manual.cs50.io\/3\/sqrtl) - square root function\n- [tan](https:\/\/manual.cs50.io\/3\/tan) - tangent function\n- [tanf](https:\/\/manual.cs50.io\/3\/tanf) - tangent function\n- [tanh](https:\/\/manual.cs50.io\/3\/tanh) - hyperbolic tangent function\n- [tanhf](https:\/\/manual.cs50.io\/3\/tanhf) - hyperbolic tangent function\n- [tanhl](https:\/\/manual.cs50.io\/3\/tanhl) - hyperbolic tangent function\n- [tanl](https:\/\/manual.cs50.io\/3\/tanl) - tangent function\n- [tgamma](https:\/\/manual.cs50.io\/3\/tgamma) - true gamma function\n- [tgammaf](https:\/\/manual.cs50.io\/3\/tgammaf) - true gamma function\n- [tgammal](https:\/\/manual.cs50.io\/3\/tgammal) - true gamma function\n- [trunc](https:\/\/manual.cs50.io\/3\/trunc) - round to integer, toward zero\n- [truncf](https:\/\/manual.cs50.io\/3\/truncf) - round to integer, toward zero\n- [truncl](https:\/\/manual.cs50.io\/3\/truncl) - round to integer, toward zero\n- [y0](https:\/\/manual.cs50.io\/3\/y0) - Bessel functions of the second kind\n- [y0f](https:\/\/manual.cs50.io\/3\/y0f) - Bessel functions of the second kind\n- [y0l](https:\/\/manual.cs50.io\/3\/y0l) - Bessel functions of the second kind\n- [y1](https:\/\/manual.cs50.io\/3\/y1) - Bessel functions of the second kind\n- [y1f](https:\/\/manual.cs50.io\/3\/y1f) - Bessel functions of the second kind\n- [y1l](https:\/\/manual.cs50.io\/3\/y1l) - Bessel functions of the second kind\n- [yn](https:\/\/manual.cs50.io\/3\/yn) - Bessel functions of the second kind\n- [ynf](https:\/\/manual.cs50.io\/3\/ynf) - Bessel functions of the second kind\n- [ynl](https:\/\/manual.cs50.io\/3\/ynl) - Bessel functions of the second kind\n## [monetary.h](https:\/\/manual.cs50.io\/#monetary.h)\n- [strfmon](https:\/\/manual.cs50.io\/3\/strfmon) - convert monetary value to a string\n- [strfmon\\_l](https:\/\/manual.cs50.io\/3\/strfmon_l) - convert monetary value to a string\n## [mqueue.h](https:\/\/manual.cs50.io\/#mqueue.h)\n- [mq\\_close](https:\/\/manual.cs50.io\/3\/mq_close) - close a message queue descriptor\n- [mq\\_getattr](https:\/\/manual.cs50.io\/3\/mq_getattr) - get\/set message queue attributes\n- [mq\\_notify](https:\/\/manual.cs50.io\/2\/mq_notify) - register for notification when a message is available\n- [mq\\_notify](https:\/\/manual.cs50.io\/3\/mq_notify) - register for notification when a message is available\n- [mq\\_open](https:\/\/manual.cs50.io\/2\/mq_open) - open a message queue\n- [mq\\_open](https:\/\/manual.cs50.io\/3\/mq_open) - open a message queue\n- [mq\\_receive](https:\/\/manual.cs50.io\/3\/mq_receive) - receive a message from a message queue\n- [mq\\_send](https:\/\/manual.cs50.io\/3\/mq_send) - send a message to a message queue\n- [mq\\_setattr](https:\/\/manual.cs50.io\/3\/mq_setattr) - get\/set message queue attributes\n- [mq\\_timedreceive](https:\/\/manual.cs50.io\/2\/mq_timedreceive) - receive a message from a message queue\n- [mq\\_timedreceive](https:\/\/manual.cs50.io\/3\/mq_timedreceive) - receive a message from a message queue\n- [mq\\_timedsend](https:\/\/manual.cs50.io\/2\/mq_timedsend) - send a message to a message queue\n- [mq\\_timedsend](https:\/\/manual.cs50.io\/3\/mq_timedsend) - send a message to a message queue\n- [mq\\_unlink](https:\/\/manual.cs50.io\/2\/mq_unlink) - remove a message queue\n- [mq\\_unlink](https:\/\/manual.cs50.io\/3\/mq_unlink) - remove a message queue\n## [net\/if.h](https:\/\/manual.cs50.io\/#net\/if.h)\n- [if\\_freenameindex](https:\/\/manual.cs50.io\/3\/if_freenameindex) - get network interface names and indexes\n- [if\\_indextoname](https:\/\/manual.cs50.io\/3\/if_indextoname) - mappings between network interface names and indexes\n- [if\\_nameindex](https:\/\/manual.cs50.io\/3\/if_nameindex) - get network interface names and indexes\n- [if\\_nametoindex](https:\/\/manual.cs50.io\/3\/if_nametoindex) - mappings between network interface names and indexes\n## [netdb.h](https:\/\/manual.cs50.io\/#netdb.h)\n- [endhostent](https:\/\/manual.cs50.io\/3\/endhostent) - get network host entry\n- [endnetent](https:\/\/manual.cs50.io\/3\/endnetent) - get network entry\n- [endnetgrent](https:\/\/manual.cs50.io\/3\/endnetgrent) - handle network group entries\n- [endprotoent](https:\/\/manual.cs50.io\/3\/endprotoent) - get protocol entry\n- [endrpcent](https:\/\/manual.cs50.io\/3\/endrpcent) - get RPC entry\n- [endservent](https:\/\/manual.cs50.io\/3\/endservent) - get service entry\n- [gai\\_cancel](https:\/\/manual.cs50.io\/3\/gai_cancel) - asynchronous network address and service translation\n- [gai\\_error](https:\/\/manual.cs50.io\/3\/gai_error) - asynchronous network address and service translation\n- [gai\\_suspend](https:\/\/manual.cs50.io\/3\/gai_suspend) - asynchronous network address and service translation\n- [getaddrinfo\\_a](https:\/\/manual.cs50.io\/3\/getaddrinfo_a) - asynchronous network address and service translation\n- [gethostbyaddr](https:\/\/manual.cs50.io\/3\/gethostbyaddr) - get network host entry\n- [gethostbyaddr\\_r](https:\/\/manual.cs50.io\/3\/gethostbyaddr_r) - get network host entry\n- [gethostbyname](https:\/\/manual.cs50.io\/3\/gethostbyname) - get network host entry\n- [gethostbyname2](https:\/\/manual.cs50.io\/3\/gethostbyname2) - get network host entry\n- [gethostbyname2\\_r](https:\/\/manual.cs50.io\/3\/gethostbyname2_r) - get network host entry\n- [gethostbyname\\_r](https:\/\/manual.cs50.io\/3\/gethostbyname_r) - get network host entry\n- [gethostent](https:\/\/manual.cs50.io\/3\/gethostent) - get network host entry\n- [gethostent\\_r](https:\/\/manual.cs50.io\/3\/gethostent_r) - get network host entry\n- [getnetbyaddr](https:\/\/manual.cs50.io\/3\/getnetbyaddr) - get network entry\n- [getnetbyaddr\\_r](https:\/\/manual.cs50.io\/3\/getnetbyaddr_r) - get network entry (reentrant)\n- [getnetbyname](https:\/\/manual.cs50.io\/3\/getnetbyname) - get network entry\n- [getnetbyname\\_r](https:\/\/manual.cs50.io\/3\/getnetbyname_r) - get network entry (reentrant)\n- [getnetent](https:\/\/manual.cs50.io\/3\/getnetent) - get network entry\n- [getnetent\\_r](https:\/\/manual.cs50.io\/3\/getnetent_r) - get network entry (reentrant)\n- [getnetgrent](https:\/\/manual.cs50.io\/3\/getnetgrent) - handle network group entries\n- [getnetgrent\\_r](https:\/\/manual.cs50.io\/3\/getnetgrent_r) - handle network group entries\n- [getprotobyname](https:\/\/manual.cs50.io\/3\/getprotobyname) - get protocol entry\n- [getprotobyname\\_r](https:\/\/manual.cs50.io\/3\/getprotobyname_r) - get protocol entry (reentrant)\n- [getprotobynumber](https:\/\/manual.cs50.io\/3\/getprotobynumber) - get protocol entry\n- [getprotobynumber\\_r](https:\/\/manual.cs50.io\/3\/getprotobynumber_r) - get protocol entry (reentrant)\n- [getprotoent](https:\/\/manual.cs50.io\/3\/getprotoent) - get protocol entry\n- [getprotoent\\_r](https:\/\/manual.cs50.io\/3\/getprotoent_r) - get protocol entry (reentrant)\n- [getrpcbyname](https:\/\/manual.cs50.io\/3\/getrpcbyname) - get RPC entry\n- [getrpcbyname\\_r](https:\/\/manual.cs50.io\/3\/getrpcbyname_r) - get RPC entry (reentrant)\n- [getrpcbynumber](https:\/\/manual.cs50.io\/3\/getrpcbynumber) - get RPC entry\n- [getrpcbynumber\\_r](https:\/\/manual.cs50.io\/3\/getrpcbynumber_r) - get RPC entry (reentrant)\n- [getrpcent](https:\/\/manual.cs50.io\/3\/getrpcent) - get RPC entry\n- [getrpcent\\_r](https:\/\/manual.cs50.io\/3\/getrpcent_r) - get RPC entry (reentrant)\n- [getservbyname](https:\/\/manual.cs50.io\/3\/getservbyname) - get service entry\n- [getservbyname\\_r](https:\/\/manual.cs50.io\/3\/getservbyname_r) - get service entry (reentrant)\n- [getservbyport](https:\/\/manual.cs50.io\/3\/getservbyport) - get service entry\n- [getservbyport\\_r](https:\/\/manual.cs50.io\/3\/getservbyport_r) - get service entry (reentrant)\n- [getservent](https:\/\/manual.cs50.io\/3\/getservent) - get service entry\n- [getservent\\_r](https:\/\/manual.cs50.io\/3\/getservent_r) - get service entry (reentrant)\n- [h\\_errno](https:\/\/manual.cs50.io\/3\/h_errno) - get network host entry\n- [herror](https:\/\/manual.cs50.io\/3\/herror) - get network host entry\n- [hstrerror](https:\/\/manual.cs50.io\/3\/hstrerror) - get network host entry\n- [innetgr](https:\/\/manual.cs50.io\/3\/innetgr) - handle network group entries\n- [rexec](https:\/\/manual.cs50.io\/3\/rexec) - return stream to a remote command\n- [rexec\\_af](https:\/\/manual.cs50.io\/3\/rexec_af) - return stream to a remote command\n- [sethostent](https:\/\/manual.cs50.io\/3\/sethostent) - get network host entry\n- [setnetent](https:\/\/manual.cs50.io\/3\/setnetent) - get network entry\n- [setnetgrent](https:\/\/manual.cs50.io\/3\/setnetgrent) - handle network group entries\n- [setprotoent](https:\/\/manual.cs50.io\/3\/setprotoent) - get protocol entry\n- [setrpcent](https:\/\/manual.cs50.io\/3\/setrpcent) - get RPC entry\n- [setservent](https:\/\/manual.cs50.io\/3\/setservent) - get service entry\n## [netinet\/in.h](https:\/\/manual.cs50.io\/#netinet\/in.h)\n- [dn\\_comp](https:\/\/manual.cs50.io\/3\/dn_comp) - resolver routines\n- [dn\\_expand](https:\/\/manual.cs50.io\/3\/dn_expand) - resolver routines\n- [res\\_init](https:\/\/manual.cs50.io\/3\/res_init) - resolver routines\n- [res\\_mkquery](https:\/\/manual.cs50.io\/3\/res_mkquery) - resolver routines\n- [res\\_nclose](https:\/\/manual.cs50.io\/3\/res_nclose) - resolver routines\n- [res\\_ninit](https:\/\/manual.cs50.io\/3\/res_ninit) - resolver routines\n- [res\\_nmkquery](https:\/\/manual.cs50.io\/3\/res_nmkquery) - resolver routines\n- [res\\_nquery](https:\/\/manual.cs50.io\/3\/res_nquery) - resolver routines\n- [res\\_nquerydomain](https:\/\/manual.cs50.io\/3\/res_nquerydomain) - resolver routines\n- [res\\_nsearch](https:\/\/manual.cs50.io\/3\/res_nsearch) - resolver routines\n- [res\\_nsend](https:\/\/manual.cs50.io\/3\/res_nsend) - resolver routines\n- [res\\_query](https:\/\/manual.cs50.io\/3\/res_query) - resolver routines\n- [res\\_querydomain](https:\/\/manual.cs50.io\/3\/res_querydomain) - resolver routines\n- [res\\_search](https:\/\/manual.cs50.io\/3\/res_search) - resolver routines\n- [res\\_send](https:\/\/manual.cs50.io\/3\/res_send) - resolver routines\n- [resolver](https:\/\/manual.cs50.io\/3\/resolver) - resolver routines\n## [nl\\_types.h](https:\/\/manual.cs50.io\/#nl_types.h)\n- [catclose](https:\/\/manual.cs50.io\/3\/catclose) - open\/close a message catalog\n- [catgets](https:\/\/manual.cs50.io\/3\/catgets) - get message from a message catalog\n- [catopen](https:\/\/manual.cs50.io\/3\/catopen) - open\/close a message catalog\n## [poll.h](https:\/\/manual.cs50.io\/#poll.h)\n- [poll](https:\/\/manual.cs50.io\/2\/poll) - wait for some event on a file descriptor\n- [ppoll](https:\/\/manual.cs50.io\/2\/ppoll) - wait for some event on a file descriptor\n## [pthread.h](https:\/\/manual.cs50.io\/#pthread.h)\n- [pthread\\_attr\\_destroy](https:\/\/manual.cs50.io\/3\/pthread_attr_destroy) - initialize and destroy thread attributes object\n- [pthread\\_attr\\_getaffinity\\_np](https:\/\/manual.cs50.io\/3\/pthread_attr_getaffinity_np) - set\/get CPU affinity attribute in thread at...\n- [pthread\\_attr\\_getdetachstate](https:\/\/manual.cs50.io\/3\/pthread_attr_getdetachstate) - set\/get detach state attribute in thread at...\n- [pthread\\_attr\\_getguardsize](https:\/\/manual.cs50.io\/3\/pthread_attr_getguardsize) - set\/get guard size attribute in thread attrib...\n- [pthread\\_attr\\_getinheritsched](https:\/\/manual.cs50.io\/3\/pthread_attr_getinheritsched) - set\/get inherit-scheduler attribute in thr...\n- [pthread\\_attr\\_getschedparam](https:\/\/manual.cs50.io\/3\/pthread_attr_getschedparam) - set\/get scheduling parameter attributes in t...\n- [pthread\\_attr\\_getschedpolicy](https:\/\/manual.cs50.io\/3\/pthread_attr_getschedpolicy) - set\/get scheduling policy attribute in thre...\n- [pthread\\_attr\\_getscope](https:\/\/manual.cs50.io\/3\/pthread_attr_getscope) - set\/get contention scope attribute in thread attr...\n- [pthread\\_attr\\_getsigmask\\_np](https:\/\/manual.cs50.io\/3\/pthread_attr_getsigmask_np) - set\/get signal mask attribute in thread attr...\n- [pthread\\_attr\\_getstack](https:\/\/manual.cs50.io\/3\/pthread_attr_getstack) - set\/get stack attributes in thread attributes object\n- [pthread\\_attr\\_getstackaddr](https:\/\/manual.cs50.io\/3\/pthread_attr_getstackaddr) - set\/get stack address attribute in thread att...\n- [pthread\\_attr\\_getstacksize](https:\/\/manual.cs50.io\/3\/pthread_attr_getstacksize) - set\/get stack size attribute in thread attrib...\n- [pthread\\_attr\\_init](https:\/\/manual.cs50.io\/3\/pthread_attr_init) - initialize and destroy thread attributes object\n- [pthread\\_attr\\_setaffinity\\_np](https:\/\/manual.cs50.io\/3\/pthread_attr_setaffinity_np) - set\/get CPU affinity attribute in thread at...\n- [pthread\\_attr\\_setdetachstate](https:\/\/manual.cs50.io\/3\/pthread_attr_setdetachstate) - set\/get detach state attribute in thread at...\n- [pthread\\_attr\\_setguardsize](https:\/\/manual.cs50.io\/3\/pthread_attr_setguardsize) - set\/get guard size attribute in thread attrib...\n- [pthread\\_attr\\_setinheritsched](https:\/\/manual.cs50.io\/3\/pthread_attr_setinheritsched) - set\/get inherit-scheduler attribute in thr...\n- [pthread\\_attr\\_setschedparam](https:\/\/manual.cs50.io\/3\/pthread_attr_setschedparam) - set\/get scheduling parameter attributes in t...\n- [pthread\\_attr\\_setschedpolicy](https:\/\/manual.cs50.io\/3\/pthread_attr_setschedpolicy) - set\/get scheduling policy attribute in thre...\n- [pthread\\_attr\\_setscope](https:\/\/manual.cs50.io\/3\/pthread_attr_setscope) - set\/get contention scope attribute in thread attr...\n- [pthread\\_attr\\_setsigmask\\_np](https:\/\/manual.cs50.io\/3\/pthread_attr_setsigmask_np) - set\/get signal mask attribute in thread attr...\n- [pthread\\_attr\\_setstack](https:\/\/manual.cs50.io\/3\/pthread_attr_setstack) - set\/get stack attributes in thread attributes object\n- [pthread\\_attr\\_setstackaddr](https:\/\/manual.cs50.io\/3\/pthread_attr_setstackaddr) - set\/get stack address attribute in thread att...\n- [pthread\\_attr\\_setstacksize](https:\/\/manual.cs50.io\/3\/pthread_attr_setstacksize) - set\/get stack size attribute in thread attrib...\n- [pthread\\_cancel](https:\/\/manual.cs50.io\/3\/pthread_cancel) - send a cancelation request to a thread\n- [pthread\\_cleanup\\_pop](https:\/\/manual.cs50.io\/3\/pthread_cleanup_pop) - push and pop thread cancelation clean-up handlers\n- [pthread\\_cleanup\\_pop\\_restore\\_np](https:\/\/manual.cs50.io\/3\/pthread_cleanup_pop_restore_np) - push and pop thread cancelation clean-up...\n- [pthread\\_cleanup\\_push](https:\/\/manual.cs50.io\/3\/pthread_cleanup_push) - push and pop thread cancelation clean-up handlers\n- [pthread\\_cleanup\\_push\\_defer\\_np](https:\/\/manual.cs50.io\/3\/pthread_cleanup_push_defer_np) - push and pop thread cancelation clean-up ...\n- [pthread\\_create](https:\/\/manual.cs50.io\/3\/pthread_create) - create a new thread\n- [pthread\\_detach](https:\/\/manual.cs50.io\/3\/pthread_detach) - detach a thread\n- [pthread\\_equal](https:\/\/manual.cs50.io\/3\/pthread_equal) - compare thread IDs\n- [pthread\\_exit](https:\/\/manual.cs50.io\/3\/pthread_exit) - terminate calling thread\n- [pthread\\_getaffinity\\_np](https:\/\/manual.cs50.io\/3\/pthread_getaffinity_np) - set\/get CPU affinity of a thread\n- [pthread\\_getattr\\_default\\_np](https:\/\/manual.cs50.io\/3\/pthread_getattr_default_np) - get or set default thread-creation attributes\n- [pthread\\_getattr\\_np](https:\/\/manual.cs50.io\/3\/pthread_getattr_np) - get attributes of created thread\n- [pthread\\_getconcurrency](https:\/\/manual.cs50.io\/3\/pthread_getconcurrency) - set\/get the concurrency level\n- [pthread\\_getcpuclockid](https:\/\/manual.cs50.io\/3\/pthread_getcpuclockid) - retrieve ID of a thread's CPU time clock\n- [pthread\\_getname\\_np](https:\/\/manual.cs50.io\/3\/pthread_getname_np) - set\/get the name of a thread\n- [pthread\\_getschedparam](https:\/\/manual.cs50.io\/3\/pthread_getschedparam) - set\/get scheduling policy and parameters of a thread\n- [pthread\\_join](https:\/\/manual.cs50.io\/3\/pthread_join) - join with a terminated thread\n- [pthread\\_kill\\_other\\_threads\\_np](https:\/\/manual.cs50.io\/3\/pthread_kill_other_threads_np) - terminate all other threads in process\n- [pthread\\_mutex\\_consistent](https:\/\/manual.cs50.io\/3\/pthread_mutex_consistent) - make a robust mutex consistent\n- [pthread\\_mutex\\_consistent\\_np](https:\/\/manual.cs50.io\/3\/pthread_mutex_consistent_np) - make a robust mutex consistent\n- [pthread\\_mutexattr\\_getpshared](https:\/\/manual.cs50.io\/3\/pthread_mutexattr_getpshared) - get\/set process-shared mutex attribute\n- [pthread\\_mutexattr\\_getrobust](https:\/\/manual.cs50.io\/3\/pthread_mutexattr_getrobust) - get and set the robustness attribute of a m...\n- [pthread\\_mutexattr\\_getrobust\\_np](https:\/\/manual.cs50.io\/3\/pthread_mutexattr_getrobust_np) - get and set the robustness attribute of ...\n- [pthread\\_mutexattr\\_setpshared](https:\/\/manual.cs50.io\/3\/pthread_mutexattr_setpshared) - get\/set process-shared mutex attribute\n- [pthread\\_mutexattr\\_setrobust](https:\/\/manual.cs50.io\/3\/pthread_mutexattr_setrobust) - get and set the robustness attribute of a m...\n- [pthread\\_mutexattr\\_setrobust\\_np](https:\/\/manual.cs50.io\/3\/pthread_mutexattr_setrobust_np) - get and set the robustness attribute of ...\n- [pthread\\_rwlockattr\\_getkind\\_np](https:\/\/manual.cs50.io\/3\/pthread_rwlockattr_getkind_np) - set\/get the read-write lock kind of the t...\n- [pthread\\_rwlockattr\\_setkind\\_np](https:\/\/manual.cs50.io\/3\/pthread_rwlockattr_setkind_np) - set\/get the read-write lock kind of the t...\n- [pthread\\_self](https:\/\/manual.cs50.io\/3\/pthread_self) - obtain ID of the calling thread\n- [pthread\\_setaffinity\\_np](https:\/\/manual.cs50.io\/3\/pthread_setaffinity_np) - set\/get CPU affinity of a thread\n- [pthread\\_setattr\\_default\\_np](https:\/\/manual.cs50.io\/3\/pthread_setattr_default_np) - get or set default thread-creation attributes\n- [pthread\\_setcancelstate](https:\/\/manual.cs50.io\/3\/pthread_setcancelstate) - set cancelability state and type\n- [pthread\\_setcanceltype](https:\/\/manual.cs50.io\/3\/pthread_setcanceltype) - set cancelability state and type\n- [pthread\\_setconcurrency](https:\/\/manual.cs50.io\/3\/pthread_setconcurrency) - set\/get the concurrency level\n- [pthread\\_setname\\_np](https:\/\/manual.cs50.io\/3\/pthread_setname_np) - set\/get the name of a thread\n- [pthread\\_setschedparam](https:\/\/manual.cs50.io\/3\/pthread_setschedparam) - set\/get scheduling policy and parameters of a thread\n- [pthread\\_setschedprio](https:\/\/manual.cs50.io\/3\/pthread_setschedprio) - set scheduling priority of a thread\n- [pthread\\_spin\\_destroy](https:\/\/manual.cs50.io\/3\/pthread_spin_destroy) - initialize or destroy a spin lock\n- [pthread\\_spin\\_init](https:\/\/manual.cs50.io\/3\/pthread_spin_init) - initialize or destroy a spin lock\n- [pthread\\_spin\\_lock](https:\/\/manual.cs50.io\/3\/pthread_spin_lock) - lock and unlock a spin lock\n- [pthread\\_spin\\_trylock](https:\/\/manual.cs50.io\/3\/pthread_spin_trylock) - lock and unlock a spin lock\n- [pthread\\_spin\\_unlock](https:\/\/manual.cs50.io\/3\/pthread_spin_unlock) - lock and unlock a spin lock\n- [pthread\\_testcancel](https:\/\/manual.cs50.io\/3\/pthread_testcancel) - request delivery of any pending cancelation request\n- [pthread\\_timedjoin\\_np](https:\/\/manual.cs50.io\/3\/pthread_timedjoin_np) - try to join with a terminated thread\n- [pthread\\_tryjoin\\_np](https:\/\/manual.cs50.io\/3\/pthread_tryjoin_np) - try to join with a terminated thread\n- [pthread\\_yield](https:\/\/manual.cs50.io\/3\/pthread_yield) - yield the processor\n## [pwd.h](https:\/\/manual.cs50.io\/#pwd.h)\n- [fgetpwent\\_r](https:\/\/manual.cs50.io\/3\/fgetpwent_r) - get passwd file entry reentrantly\n- [getpwent\\_r](https:\/\/manual.cs50.io\/3\/getpwent_r) - get passwd file entry reentrantly\n## [regex.h](https:\/\/manual.cs50.io\/#regex.h)\n- [regcomp](https:\/\/manual.cs50.io\/3\/regcomp) - POSIX regex functions\n- [regerror](https:\/\/manual.cs50.io\/3\/regerror) - POSIX regex functions\n- [regex](https:\/\/manual.cs50.io\/3\/regex) - POSIX regex functions\n- [regexec](https:\/\/manual.cs50.io\/3\/regexec) - POSIX regex functions\n- [regfree](https:\/\/manual.cs50.io\/3\/regfree) - POSIX regex functions\n## [sched.h](https:\/\/manual.cs50.io\/#sched.h)\n- [\\_\\_clone2](https:\/\/manual.cs50.io\/2\/__clone2) - create a child process\n- [clone](https:\/\/manual.cs50.io\/2\/clone) - create a child process\n- [clone2](https:\/\/manual.cs50.io\/2\/clone2) - create a child process\n- [clone3](https:\/\/manual.cs50.io\/2\/clone3) - create a child process\n- [CPU\\_ALLOC](https:\/\/manual.cs50.io\/3\/CPU_ALLOC) - macros for manipulating CPU sets\n- [CPU\\_ALLOC\\_SIZE](https:\/\/manual.cs50.io\/3\/CPU_ALLOC_SIZE) - macros for manipulating CPU sets\n- [CPU\\_AND](https:\/\/manual.cs50.io\/3\/CPU_AND) - macros for manipulating CPU sets\n- [CPU\\_AND\\_S](https:\/\/manual.cs50.io\/3\/CPU_AND_S) - macros for manipulating CPU sets\n- [CPU\\_CLR](https:\/\/manual.cs50.io\/3\/CPU_CLR) - macros for manipulating CPU sets\n- [CPU\\_CLR\\_S](https:\/\/manual.cs50.io\/3\/CPU_CLR_S) - macros for manipulating CPU sets\n- [CPU\\_COUNT](https:\/\/manual.cs50.io\/3\/CPU_COUNT) - macros for manipulating CPU sets\n- [CPU\\_COUNT\\_S](https:\/\/manual.cs50.io\/3\/CPU_COUNT_S) - macros for manipulating CPU sets\n- [CPU\\_EQUAL](https:\/\/manual.cs50.io\/3\/CPU_EQUAL) - macros for manipulating CPU sets\n- [CPU\\_EQUAL\\_S](https:\/\/manual.cs50.io\/3\/CPU_EQUAL_S) - macros for manipulating CPU sets\n- [CPU\\_FREE](https:\/\/manual.cs50.io\/3\/CPU_FREE) - macros for manipulating CPU sets\n- [CPU\\_ISSET](https:\/\/manual.cs50.io\/3\/CPU_ISSET) - macros for manipulating CPU sets\n- [CPU\\_ISSET\\_S](https:\/\/manual.cs50.io\/3\/CPU_ISSET_S) - macros for manipulating CPU sets\n- [CPU\\_OR](https:\/\/manual.cs50.io\/3\/CPU_OR) - macros for manipulating CPU sets\n- [CPU\\_OR\\_S](https:\/\/manual.cs50.io\/3\/CPU_OR_S) - macros for manipulating CPU sets\n- [CPU\\_SET](https:\/\/manual.cs50.io\/3\/CPU_SET) - macros for manipulating CPU sets\n- [CPU\\_SET\\_S](https:\/\/manual.cs50.io\/3\/CPU_SET_S) - macros for manipulating CPU sets\n- [CPU\\_XOR](https:\/\/manual.cs50.io\/3\/CPU_XOR) - macros for manipulating CPU sets\n- [CPU\\_XOR\\_S](https:\/\/manual.cs50.io\/3\/CPU_XOR_S) - macros for manipulating CPU sets\n- [CPU\\_ZERO](https:\/\/manual.cs50.io\/3\/CPU_ZERO) - macros for manipulating CPU sets\n- [CPU\\_ZERO\\_S](https:\/\/manual.cs50.io\/3\/CPU_ZERO_S) - macros for manipulating CPU sets\n- [getcpu](https:\/\/manual.cs50.io\/2\/getcpu) - determine CPU and NUMA node on which the calling threa...\n- [sched\\_get\\_priority\\_max](https:\/\/manual.cs50.io\/2\/sched_get_priority_max) - get static priority range\n- [sched\\_get\\_priority\\_min](https:\/\/manual.cs50.io\/2\/sched_get_priority_min) - get static priority range\n- [sched\\_getaffinity](https:\/\/manual.cs50.io\/2\/sched_getaffinity) - set and get a thread's CPU affinity mask\n- [sched\\_getcpu](https:\/\/manual.cs50.io\/3\/sched_getcpu) - determine CPU on which the calling thread is running\n- [sched\\_getparam](https:\/\/manual.cs50.io\/2\/sched_getparam) - set and get scheduling parameters\n- [sched\\_getscheduler](https:\/\/manual.cs50.io\/2\/sched_getscheduler) - set and get scheduling policy\/parameters\n- [sched\\_rr\\_get\\_interval](https:\/\/manual.cs50.io\/2\/sched_rr_get_interval) - get the SCHED\\_RR interval for the named process\n- [sched\\_setaffinity](https:\/\/manual.cs50.io\/2\/sched_setaffinity) - set and get a thread's CPU affinity mask\n- [sched\\_setparam](https:\/\/manual.cs50.io\/2\/sched_setparam) - set and get scheduling parameters\n- [sched\\_setscheduler](https:\/\/manual.cs50.io\/2\/sched_setscheduler) - set and get scheduling policy\/parameters\n- [sched\\_yield](https:\/\/manual.cs50.io\/2\/sched_yield) - yield the processor\n- [setns](https:\/\/manual.cs50.io\/2\/setns) - reassociate thread with a namespace\n- [unshare](https:\/\/manual.cs50.io\/2\/unshare) - disassociate parts of the process execution context\n## [search.h](https:\/\/manual.cs50.io\/#search.h)\n- [hcreate](https:\/\/manual.cs50.io\/3\/hcreate) - hash table management\n- [hcreate\\_r](https:\/\/manual.cs50.io\/3\/hcreate_r) - hash table management\n- [hdestroy](https:\/\/manual.cs50.io\/3\/hdestroy) - hash table management\n- [hdestroy\\_r](https:\/\/manual.cs50.io\/3\/hdestroy_r) - hash table management\n- [hsearch](https:\/\/manual.cs50.io\/3\/hsearch) - hash table management\n- [hsearch\\_r](https:\/\/manual.cs50.io\/3\/hsearch_r) - hash table management\n- [insque](https:\/\/manual.cs50.io\/3\/insque) - insert\/remove an item from a queue\n- [lfind](https:\/\/manual.cs50.io\/3\/lfind) - linear search of an array\n- [lsearch](https:\/\/manual.cs50.io\/3\/lsearch) - linear search of an array\n- [remque](https:\/\/manual.cs50.io\/3\/remque) - insert\/remove an item from a queue\n- [tdelete](https:\/\/manual.cs50.io\/3\/tdelete) - manage a binary search tree\n- [tdestroy](https:\/\/manual.cs50.io\/3\/tdestroy) - manage a binary search tree\n- [tfind](https:\/\/manual.cs50.io\/3\/tfind) - manage a binary search tree\n- [tsearch](https:\/\/manual.cs50.io\/3\/tsearch) - manage a binary search tree\n- [twalk](https:\/\/manual.cs50.io\/3\/twalk) - manage a binary search tree\n- [twalk\\_r](https:\/\/manual.cs50.io\/3\/twalk_r) - manage a binary search tree\n## [semaphore.h](https:\/\/manual.cs50.io\/#semaphore.h)\n- [sem\\_close](https:\/\/manual.cs50.io\/3\/sem_close) - close a named semaphore\n- [sem\\_destroy](https:\/\/manual.cs50.io\/3\/sem_destroy) - destroy an unnamed semaphore\n- [sem\\_getvalue](https:\/\/manual.cs50.io\/3\/sem_getvalue) - get the value of a semaphore\n- [sem\\_init](https:\/\/manual.cs50.io\/3\/sem_init) - initialize an unnamed semaphore\n- [sem\\_open](https:\/\/manual.cs50.io\/3\/sem_open) - initialize and open a named semaphore\n- [sem\\_post](https:\/\/manual.cs50.io\/3\/sem_post) - unlock a semaphore\n- [sem\\_timedwait](https:\/\/manual.cs50.io\/3\/sem_timedwait) - lock a semaphore\n- [sem\\_trywait](https:\/\/manual.cs50.io\/3\/sem_trywait) - lock a semaphore\n- [sem\\_unlink](https:\/\/manual.cs50.io\/3\/sem_unlink) - remove a named semaphore\n- [sem\\_wait](https:\/\/manual.cs50.io\/3\/sem_wait) - lock a semaphore\n## [setjmp.h](https:\/\/manual.cs50.io\/#setjmp.h)\n- [longjmp](https:\/\/manual.cs50.io\/3\/longjmp) - performing a nonlocal goto\n- [setjmp](https:\/\/manual.cs50.io\/3\/setjmp) - performing a nonlocal goto\n- [siglongjmp](https:\/\/manual.cs50.io\/3\/siglongjmp) - performing a nonlocal goto\n- [sigsetjmp](https:\/\/manual.cs50.io\/3\/sigsetjmp) - performing a nonlocal goto\n## [signal.h](https:\/\/manual.cs50.io\/#signal.h)\n- [bsd\\_signal](https:\/\/manual.cs50.io\/3\/bsd_signal) - signal handling with BSD semantics\n- [gsignal](https:\/\/manual.cs50.io\/3\/gsignal) - software signal facility\n- [kill](https:\/\/manual.cs50.io\/2\/kill) - send signal to a process\n- [killpg](https:\/\/manual.cs50.io\/3\/killpg) - send signal to a process group\n- [psiginfo](https:\/\/manual.cs50.io\/3\/psiginfo) - print signal description\n- [psignal](https:\/\/manual.cs50.io\/3\/psignal) - print signal description\n- [pthread\\_kill](https:\/\/manual.cs50.io\/3\/pthread_kill) - send a signal to a thread\n- [pthread\\_sigmask](https:\/\/manual.cs50.io\/3\/pthread_sigmask) - examine and change mask of blocked signals\n- [pthread\\_sigqueue](https:\/\/manual.cs50.io\/3\/pthread_sigqueue) - queue a signal and data to a thread\n- [raise](https:\/\/manual.cs50.io\/3\/raise) - send a signal to the caller\n- [rt\\_sigaction](https:\/\/manual.cs50.io\/2\/rt_sigaction) - examine and change a signal action\n- [rt\\_sigpending](https:\/\/manual.cs50.io\/2\/rt_sigpending) - examine pending signals\n- [rt\\_sigprocmask](https:\/\/manual.cs50.io\/2\/rt_sigprocmask) - examine and change blocked signals\n- [rt\\_sigsuspend](https:\/\/manual.cs50.io\/2\/rt_sigsuspend) - wait for a signal\n- [rt\\_sigtimedwait](https:\/\/manual.cs50.io\/2\/rt_sigtimedwait) - synchronously wait for queued signals\n- [sigaction](https:\/\/manual.cs50.io\/2\/sigaction) - examine and change a signal action\n- [sigaddset](https:\/\/manual.cs50.io\/3\/sigaddset) - POSIX signal set operations\n- [sigaltstack](https:\/\/manual.cs50.io\/2\/sigaltstack) - set and\/or get signal stack context\n- [sigandset](https:\/\/manual.cs50.io\/3\/sigandset) - POSIX signal set operations\n- [sigblock](https:\/\/manual.cs50.io\/3\/sigblock) - BSD signal API\n- [sigdelset](https:\/\/manual.cs50.io\/3\/sigdelset) - POSIX signal set operations\n- [sigemptyset](https:\/\/manual.cs50.io\/3\/sigemptyset) - POSIX signal set operations\n- [sigfillset](https:\/\/manual.cs50.io\/3\/sigfillset) - POSIX signal set operations\n- [siggetmask](https:\/\/manual.cs50.io\/3\/siggetmask) - BSD signal API\n- [sighold](https:\/\/manual.cs50.io\/3\/sighold) - System V signal API\n- [sigignore](https:\/\/manual.cs50.io\/3\/sigignore) - System V signal API\n- [siginterrupt](https:\/\/manual.cs50.io\/3\/siginterrupt) - allow signals to interrupt system calls\n- [sigisemptyset](https:\/\/manual.cs50.io\/3\/sigisemptyset) - POSIX signal set operations\n- [sigismember](https:\/\/manual.cs50.io\/3\/sigismember) - POSIX signal set operations\n- [sigmask](https:\/\/manual.cs50.io\/3\/sigmask) - BSD signal API\n- [signal](https:\/\/manual.cs50.io\/2\/signal) - ANSI C signal handling\n- [sigorset](https:\/\/manual.cs50.io\/3\/sigorset) - POSIX signal set operations\n- [sigpause](https:\/\/manual.cs50.io\/3\/sigpause) - atomically release blocked signals and wait for interrupt\n- [sigpending](https:\/\/manual.cs50.io\/2\/sigpending) - examine pending signals\n- [sigprocmask](https:\/\/manual.cs50.io\/2\/sigprocmask) - examine and change blocked signals\n- [sigqueue](https:\/\/manual.cs50.io\/3\/sigqueue) - queue a signal and data to a process\n- [sigrelse](https:\/\/manual.cs50.io\/3\/sigrelse) - System V signal API\n- [sigset](https:\/\/manual.cs50.io\/3\/sigset) - System V signal API\n- [sigsetmask](https:\/\/manual.cs50.io\/3\/sigsetmask) - BSD signal API\n- [sigsetops](https:\/\/manual.cs50.io\/3\/sigsetops) - POSIX signal set operations\n- [sigstack](https:\/\/manual.cs50.io\/3\/sigstack) - set and\/or get signal stack context\n- [sigsuspend](https:\/\/manual.cs50.io\/2\/sigsuspend) - wait for a signal\n- [sigtimedwait](https:\/\/manual.cs50.io\/2\/sigtimedwait) - synchronously wait for queued signals\n- [sigvec](https:\/\/manual.cs50.io\/3\/sigvec) - BSD signal API\n- [sigwait](https:\/\/manual.cs50.io\/3\/sigwait) - wait for a signal\n- [sigwaitinfo](https:\/\/manual.cs50.io\/2\/sigwaitinfo) - synchronously wait for queued signals\n- [ssignal](https:\/\/manual.cs50.io\/3\/ssignal) - software signal facility\n- [sysv\\_signal](https:\/\/manual.cs50.io\/3\/sysv_signal) - signal handling with System V semantics\n## [spawn.h](https:\/\/manual.cs50.io\/#spawn.h)\n- [posix\\_spawn](https:\/\/manual.cs50.io\/3\/posix_spawn) - spawn a process\n- [posix\\_spawnp](https:\/\/manual.cs50.io\/3\/posix_spawnp) - spawn a process\n## [stdarg.h](https:\/\/manual.cs50.io\/#stdarg.h)\n- [stdarg](https:\/\/manual.cs50.io\/3\/stdarg) - variable argument lists\n- [va\\_arg](https:\/\/manual.cs50.io\/3\/va_arg) - variable argument lists\n- [va\\_copy](https:\/\/manual.cs50.io\/3\/va_copy) - variable argument lists\n- [va\\_end](https:\/\/manual.cs50.io\/3\/va_end) - variable argument lists\n- [va\\_start](https:\/\/manual.cs50.io\/3\/va_start) - variable argument lists\n## [stddef.h](https:\/\/manual.cs50.io\/#stddef.h)\n- [offsetof](https:\/\/manual.cs50.io\/3\/offsetof) - offset of a structure member\n- [wcstoimax](https:\/\/manual.cs50.io\/3\/wcstoimax) - convert wide-character string to integer\n- [wcstoumax](https:\/\/manual.cs50.io\/3\/wcstoumax) - convert wide-character string to integer\n## [stdio.h](https:\/\/manual.cs50.io\/#stdio.h)\n- [\\_\\_fbufsize](https:\/\/manual.cs50.io\/3\/__fbufsize) - interfaces to stdio FILE structure\n- [\\_\\_flbf](https:\/\/manual.cs50.io\/3\/__flbf) - interfaces to stdio FILE structure\n- [\\_\\_fpending](https:\/\/manual.cs50.io\/3\/__fpending) - interfaces to stdio FILE structure\n- [\\_\\_fpurge](https:\/\/manual.cs50.io\/3\/__fpurge) - purge a stream\n- [\\_\\_freadable](https:\/\/manual.cs50.io\/3\/__freadable) - interfaces to stdio FILE structure\n- [\\_\\_freading](https:\/\/manual.cs50.io\/3\/__freading) - interfaces to stdio FILE structure\n- [\\_\\_fsetlocking](https:\/\/manual.cs50.io\/3\/__fsetlocking) - interfaces to stdio FILE structure\n- [\\_\\_fwritable](https:\/\/manual.cs50.io\/3\/__fwritable) - interfaces to stdio FILE structure\n- [\\_\\_fwriting](https:\/\/manual.cs50.io\/3\/__fwriting) - interfaces to stdio FILE structure\n- [\\_flushlbf](https:\/\/manual.cs50.io\/3\/_flushlbf) - interfaces to stdio FILE structure\n- [addmntent](https:\/\/manual.cs50.io\/3\/addmntent) - get filesystem descriptor file entry\n- [asprintf](https:\/\/manual.cs50.io\/3\/asprintf) - print to allocated string\n- [clearerr](https:\/\/manual.cs50.io\/3\/clearerr) - check and reset stream status\n- [clearerr\\_unlocked](https:\/\/manual.cs50.io\/3\/clearerr_unlocked) - nonlocking stdio functions\n- [ctermid](https:\/\/manual.cs50.io\/3\/ctermid) - get controlling terminal name\n- [dprintf](https:\/\/manual.cs50.io\/3\/dprintf) - formatted output conversion\n- [endmntent](https:\/\/manual.cs50.io\/3\/endmntent) - get filesystem descriptor file entry\n- [fclose](https:\/\/manual.cs50.io\/3\/fclose) - close a stream close a file\n- [fcloseall](https:\/\/manual.cs50.io\/3\/fcloseall) - close all open streams\n- [fdopen](https:\/\/manual.cs50.io\/3\/fdopen) - stream open functions\n- [feof](https:\/\/manual.cs50.io\/3\/feof) - check and reset stream status\n- [feof\\_unlocked](https:\/\/manual.cs50.io\/3\/feof_unlocked) - nonlocking stdio functions\n- [ferror](https:\/\/manual.cs50.io\/3\/ferror) - check and reset stream status\n- [ferror\\_unlocked](https:\/\/manual.cs50.io\/3\/ferror_unlocked) - nonlocking stdio functions\n- [fflush](https:\/\/manual.cs50.io\/3\/fflush) - flush a stream\n- [fflush\\_unlocked](https:\/\/manual.cs50.io\/3\/fflush_unlocked) - nonlocking stdio functions\n- [fgetc](https:\/\/manual.cs50.io\/3\/fgetc) - input of characters and strings\n- [fgetc\\_unlocked](https:\/\/manual.cs50.io\/3\/fgetc_unlocked) - nonlocking stdio functions\n- [fgetgrent](https:\/\/manual.cs50.io\/3\/fgetgrent) - get group file entry\n- [fgetpos](https:\/\/manual.cs50.io\/3\/fgetpos) - reposition a stream\n- [fgetpwent](https:\/\/manual.cs50.io\/3\/fgetpwent) - get password file entry\n- [fgets](https:\/\/manual.cs50.io\/3\/fgets) - input of characters and strings\n- [fgets\\_unlocked](https:\/\/manual.cs50.io\/3\/fgets_unlocked) - nonlocking stdio functions\n- [fgetwc](https:\/\/manual.cs50.io\/3\/fgetwc) - read a wide character from a FILE stream\n- [fgetwc\\_unlocked](https:\/\/manual.cs50.io\/3\/fgetwc_unlocked) - nonlocking stdio functions\n- [fgetws\\_unlocked](https:\/\/manual.cs50.io\/3\/fgetws_unlocked) - nonlocking stdio functions\n- [fileno](https:\/\/manual.cs50.io\/3\/fileno) - obtain file descriptor of a stdio stream\n- [fileno\\_unlocked](https:\/\/manual.cs50.io\/3\/fileno_unlocked) - nonlocking stdio functions\n- [flockfile](https:\/\/manual.cs50.io\/3\/flockfile) - lock FILE for stdio\n- [fmemopen](https:\/\/manual.cs50.io\/3\/fmemopen) - open memory as stream\n- [fopen](https:\/\/manual.cs50.io\/3\/fopen) - stream open functions open a file\n- [fopencookie](https:\/\/manual.cs50.io\/3\/fopencookie) - open a custom stream\n- [fprintf](https:\/\/manual.cs50.io\/3\/fprintf) - formatted output conversion print to a file\n- [fpurge](https:\/\/manual.cs50.io\/3\/fpurge) - purge a stream\n- [fputc](https:\/\/manual.cs50.io\/3\/fputc) - output of characters and strings\n- [fputc\\_unlocked](https:\/\/manual.cs50.io\/3\/fputc_unlocked) - nonlocking stdio functions\n- [fputs](https:\/\/manual.cs50.io\/3\/fputs) - output of characters and strings\n- [fputs\\_unlocked](https:\/\/manual.cs50.io\/3\/fputs_unlocked) - nonlocking stdio functions\n- [fputwc](https:\/\/manual.cs50.io\/3\/fputwc) - write a wide character to a FILE stream\n- [fputwc\\_unlocked](https:\/\/manual.cs50.io\/3\/fputwc_unlocked) - nonlocking stdio functions\n- [fputws\\_unlocked](https:\/\/manual.cs50.io\/3\/fputws_unlocked) - nonlocking stdio functions\n- [fread](https:\/\/manual.cs50.io\/3\/fread) - binary stream input\/output read bytes from a file\n- [fread\\_unlocked](https:\/\/manual.cs50.io\/3\/fread_unlocked) - nonlocking stdio functions\n- [freopen](https:\/\/manual.cs50.io\/3\/freopen) - stream open functions\n- [fscanf](https:\/\/manual.cs50.io\/3\/fscanf) - input FILE format conversion get input from a file\n- [fseek](https:\/\/manual.cs50.io\/3\/fseek) - reposition a stream\n- [fseeko](https:\/\/manual.cs50.io\/3\/fseeko) - seek to or report file position\n- [fsetpos](https:\/\/manual.cs50.io\/3\/fsetpos) - reposition a stream\n- [ftell](https:\/\/manual.cs50.io\/3\/ftell) - reposition a stream\n- [ftello](https:\/\/manual.cs50.io\/3\/ftello) - seek to or report file position\n- [ftrylockfile](https:\/\/manual.cs50.io\/3\/ftrylockfile) - lock FILE for stdio\n- [funlockfile](https:\/\/manual.cs50.io\/3\/funlockfile) - lock FILE for stdio\n- [fwprintf](https:\/\/manual.cs50.io\/3\/fwprintf) - formatted wide-character output conversion\n- [fwrite](https:\/\/manual.cs50.io\/3\/fwrite) - binary stream input\/output write bytes to a file\n- [fwrite\\_unlocked](https:\/\/manual.cs50.io\/3\/fwrite_unlocked) - nonlocking stdio functions\n- [getc](https:\/\/manual.cs50.io\/3\/getc) - input of characters and strings\n- [getc\\_unlocked](https:\/\/manual.cs50.io\/3\/getc_unlocked) - nonlocking stdio functions\n- [getchar](https:\/\/manual.cs50.io\/3\/getchar) - input of characters and strings\n- [getchar\\_unlocked](https:\/\/manual.cs50.io\/3\/getchar_unlocked) - nonlocking stdio functions\n- [getdelim](https:\/\/manual.cs50.io\/3\/getdelim) - delimited string input\n- [getline](https:\/\/manual.cs50.io\/3\/getline) - delimited string input\n- [getmntent](https:\/\/manual.cs50.io\/3\/getmntent) - get filesystem descriptor file entry\n- [getmntent\\_r](https:\/\/manual.cs50.io\/3\/getmntent_r) - get filesystem descriptor file entry\n- [gets](https:\/\/manual.cs50.io\/3\/gets) - get a string from standard input (DEPRECATED)\n- [getw](https:\/\/manual.cs50.io\/3\/getw) - input and output of words (ints)\n- [getwc](https:\/\/manual.cs50.io\/3\/getwc) - read a wide character from a FILE stream\n- [getwc\\_unlocked](https:\/\/manual.cs50.io\/3\/getwc_unlocked) - nonlocking stdio functions\n- [getwchar\\_unlocked](https:\/\/manual.cs50.io\/3\/getwchar_unlocked) - nonlocking stdio functions\n- [hasmntopt](https:\/\/manual.cs50.io\/3\/hasmntopt) - get filesystem descriptor file entry\n- [open\\_memstream](https:\/\/manual.cs50.io\/3\/open_memstream) - open a dynamic memory buffer stream\n- [open\\_wmemstream](https:\/\/manual.cs50.io\/3\/open_wmemstream) - open a dynamic memory buffer stream\n- [pclose](https:\/\/manual.cs50.io\/3\/pclose) - pipe stream to or from a process\n- [perror](https:\/\/manual.cs50.io\/3\/perror) - print a system error message\n- [popen](https:\/\/manual.cs50.io\/3\/popen) - pipe stream to or from a process\n- [printf](https:\/\/manual.cs50.io\/3\/printf) - formatted output conversion print to the screen\n- [putc](https:\/\/manual.cs50.io\/3\/putc) - output of characters and strings\n- [putc\\_unlocked](https:\/\/manual.cs50.io\/3\/putc_unlocked) - nonlocking stdio functions\n- [putchar](https:\/\/manual.cs50.io\/3\/putchar) - output of characters and strings\n- [putchar\\_unlocked](https:\/\/manual.cs50.io\/3\/putchar_unlocked) - nonlocking stdio functions\n- [putpwent](https:\/\/manual.cs50.io\/3\/putpwent) - write a password file entry\n- [puts](https:\/\/manual.cs50.io\/3\/puts) - output of characters and strings\n- [putw](https:\/\/manual.cs50.io\/3\/putw) - input and output of words (ints)\n- [putwc](https:\/\/manual.cs50.io\/3\/putwc) - write a wide character to a FILE stream\n- [putwc\\_unlocked](https:\/\/manual.cs50.io\/3\/putwc_unlocked) - nonlocking stdio functions\n- [putwchar\\_unlocked](https:\/\/manual.cs50.io\/3\/putwchar_unlocked) - nonlocking stdio functions\n- [remove](https:\/\/manual.cs50.io\/3\/remove) - remove a file or directory\n- [rename](https:\/\/manual.cs50.io\/2\/rename) - change the name or location of a file\n- [renameat](https:\/\/manual.cs50.io\/2\/renameat) - change the name or location of a file\n- [renameat2](https:\/\/manual.cs50.io\/2\/renameat2) - change the name or location of a file\n- [rewind](https:\/\/manual.cs50.io\/3\/rewind) - reposition a stream\n- [scanf](https:\/\/manual.cs50.io\/3\/scanf) - input FILE format conversion get input from a user\n- [setbuf](https:\/\/manual.cs50.io\/3\/setbuf) - stream buffering operations\n- [setbuffer](https:\/\/manual.cs50.io\/3\/setbuffer) - stream buffering operations\n- [setlinebuf](https:\/\/manual.cs50.io\/3\/setlinebuf) - stream buffering operations\n- [setmntent](https:\/\/manual.cs50.io\/3\/setmntent) - get filesystem descriptor file entry\n- [setvbuf](https:\/\/manual.cs50.io\/3\/setvbuf) - stream buffering operations\n- [snprintf](https:\/\/manual.cs50.io\/3\/snprintf) - formatted output conversion\n- [sprintf](https:\/\/manual.cs50.io\/3\/sprintf) - formatted output conversion print to a string\n- [sscanf](https:\/\/manual.cs50.io\/3\/sscanf) - input string format conversion\n- [stderr](https:\/\/manual.cs50.io\/3\/stderr) - standard I\/O streams\n- [stdin](https:\/\/manual.cs50.io\/3\/stdin) - standard I\/O streams\n- [stdio](https:\/\/manual.cs50.io\/3\/stdio) - standard input\/output library functions\n- [stdio\\_ext](https:\/\/manual.cs50.io\/3\/stdio_ext) - interfaces to stdio FILE structure\n- [stdout](https:\/\/manual.cs50.io\/3\/stdout) - standard I\/O streams\n- [swprintf](https:\/\/manual.cs50.io\/3\/swprintf) - formatted wide-character output conversion\n- [sys\\_errlist](https:\/\/manual.cs50.io\/3\/sys_errlist) - print a system error message\n- [sys\\_nerr](https:\/\/manual.cs50.io\/3\/sys_nerr) - print a system error message\n- [tempnam](https:\/\/manual.cs50.io\/3\/tempnam) - create a name for a temporary file\n- [tmpfile](https:\/\/manual.cs50.io\/3\/tmpfile) - create a temporary file\n- [tmpnam](https:\/\/manual.cs50.io\/3\/tmpnam) - create a name for a temporary file\n- [tmpnam\\_r](https:\/\/manual.cs50.io\/3\/tmpnam_r) - create a name for a temporary file\n- [ungetc](https:\/\/manual.cs50.io\/3\/ungetc) - input of characters and strings\n- [unlocked\\_stdio](https:\/\/manual.cs50.io\/3\/unlocked_stdio) - nonlocking stdio functions\n- [vasprintf](https:\/\/manual.cs50.io\/3\/vasprintf) - print to allocated string\n- [vdprintf](https:\/\/manual.cs50.io\/3\/vdprintf) - formatted output conversion\n- [vfprintf](https:\/\/manual.cs50.io\/3\/vfprintf) - formatted output conversion\n- [vfscanf](https:\/\/manual.cs50.io\/3\/vfscanf) - input FILE format conversion\n- [vfwprintf](https:\/\/manual.cs50.io\/3\/vfwprintf) - formatted wide-character output conversion\n- [vprintf](https:\/\/manual.cs50.io\/3\/vprintf) - formatted output conversion\n- [vscanf](https:\/\/manual.cs50.io\/3\/vscanf) - input FILE format conversion\n- [vsnprintf](https:\/\/manual.cs50.io\/3\/vsnprintf) - formatted output conversion\n- [vsprintf](https:\/\/manual.cs50.io\/3\/vsprintf) - formatted output conversion\n- [vsscanf](https:\/\/manual.cs50.io\/3\/vsscanf) - input string format conversion\n- [vswprintf](https:\/\/manual.cs50.io\/3\/vswprintf) - formatted wide-character output conversion\n- [vwprintf](https:\/\/manual.cs50.io\/3\/vwprintf) - formatted wide-character output conversion\n- [wprintf](https:\/\/manual.cs50.io\/3\/wprintf) - formatted wide-character output conversion\n## [stdlib.h](https:\/\/manual.cs50.io\/#stdlib.h)\n- [a64l](https:\/\/manual.cs50.io\/3\/a64l) - convert between long and base-64\n- [abort](https:\/\/manual.cs50.io\/3\/abort) - cause abnormal process termination\n- [abs](https:\/\/manual.cs50.io\/3\/abs) - compute the absolute value of an integer\n- [aligned\\_alloc](https:\/\/manual.cs50.io\/3\/aligned_alloc) - allocate aligned memory\n- [arc4random](https:\/\/manual.cs50.io\/3\/arc4random) - cryptographically-secure pseudorandom number generator\n- [arc4random\\_buf](https:\/\/manual.cs50.io\/3\/arc4random_buf) - cryptographically-secure pseudorandom number generator\n- [arc4random\\_uniform](https:\/\/manual.cs50.io\/3\/arc4random_uniform) - cryptographically-secure pseudorandom number generator\n- [atexit](https:\/\/manual.cs50.io\/3\/atexit) - register a function to be called at normal process ter...\n- [atof](https:\/\/manual.cs50.io\/3\/atof) - convert a string to a double convert a `string` to a `float`\n- [atoi](https:\/\/manual.cs50.io\/3\/atoi) - convert a string to an integer convert a `string` to an `int`\n- [atol](https:\/\/manual.cs50.io\/3\/atol) - convert a string to an integer convert a `string` to a `long`\n- [atoll](https:\/\/manual.cs50.io\/3\/atoll) - convert a string to an integer\n- [atoq](https:\/\/manual.cs50.io\/3\/atoq) - convert a string to an integer\n- [bsearch](https:\/\/manual.cs50.io\/3\/bsearch) - binary search of a sorted array\n- [calloc](https:\/\/manual.cs50.io\/3\/calloc) - allocate and free dynamic memory\n- [canonicalize\\_file\\_name](https:\/\/manual.cs50.io\/3\/canonicalize_file_name) - return the canonicalized absolute pathname\n- [cfree](https:\/\/manual.cs50.io\/3\/cfree) - free allocated memory\n- [clearenv](https:\/\/manual.cs50.io\/3\/clearenv) - clear the environment\n- [div](https:\/\/manual.cs50.io\/3\/div) - compute quotient and remainder of an integer division\n- [drand48](https:\/\/manual.cs50.io\/3\/drand48) - generate uniformly distributed pseudo-random numbers\n- [drand48\\_r](https:\/\/manual.cs50.io\/3\/drand48_r) - generate uniformly distributed pseudo-random numbers r...\n- [ecvt](https:\/\/manual.cs50.io\/3\/ecvt) - convert a floating-point number to a string\n- [ecvt\\_r](https:\/\/manual.cs50.io\/3\/ecvt_r) - convert a floating-point number to a string\n- [erand48](https:\/\/manual.cs50.io\/3\/erand48) - generate uniformly distributed pseudo-random numbers\n- [erand48\\_r](https:\/\/manual.cs50.io\/3\/erand48_r) - generate uniformly distributed pseudo-random numbers r...\n- [exit](https:\/\/manual.cs50.io\/3\/exit) - cause normal process termination\n- [fcvt](https:\/\/manual.cs50.io\/3\/fcvt) - convert a floating-point number to a string\n- [fcvt\\_r](https:\/\/manual.cs50.io\/3\/fcvt_r) - convert a floating-point number to a string\n- [free](https:\/\/manual.cs50.io\/3\/free) - allocate and free dynamic memory free dynamically allocated memory\n- [gcvt](https:\/\/manual.cs50.io\/3\/gcvt) - convert a floating-point number to a string\n- [getenv](https:\/\/manual.cs50.io\/3\/getenv) - get an environment variable\n- [getloadavg](https:\/\/manual.cs50.io\/3\/getloadavg) - get system load averages\n- [getpt](https:\/\/manual.cs50.io\/3\/getpt) - open a new pseudoterminal master\n- [getsubopt](https:\/\/manual.cs50.io\/3\/getsubopt) - parse suboption arguments from a string\n- [grantpt](https:\/\/manual.cs50.io\/3\/grantpt) - grant access to the slave pseudoterminal\n- [imaxabs](https:\/\/manual.cs50.io\/3\/imaxabs) - compute the absolute value of an integer\n- [imaxdiv](https:\/\/manual.cs50.io\/3\/imaxdiv) - compute quotient and remainder of an integer division\n- [initstate](https:\/\/manual.cs50.io\/3\/initstate) - random number generator\n- [initstate\\_r](https:\/\/manual.cs50.io\/3\/initstate_r) - reentrant random number generator\n- [jrand48](https:\/\/manual.cs50.io\/3\/jrand48) - generate uniformly distributed pseudo-random numbers\n- [jrand48\\_r](https:\/\/manual.cs50.io\/3\/jrand48_r) - generate uniformly distributed pseudo-random numbers r...\n- [l64a](https:\/\/manual.cs50.io\/3\/l64a) - convert between long and base-64\n- [labs](https:\/\/manual.cs50.io\/3\/labs) - compute the absolute value of an integer\n- [lcong48](https:\/\/manual.cs50.io\/3\/lcong48) - generate uniformly distributed pseudo-random numbers\n- [lcong48\\_r](https:\/\/manual.cs50.io\/3\/lcong48_r) - generate uniformly distributed pseudo-random numbers r...\n- [ldiv](https:\/\/manual.cs50.io\/3\/ldiv) - compute quotient and remainder of an integer division\n- [llabs](https:\/\/manual.cs50.io\/3\/llabs) - compute the absolute value of an integer\n- [lldiv](https:\/\/manual.cs50.io\/3\/lldiv) - compute quotient and remainder of an integer division\n- [lrand48](https:\/\/manual.cs50.io\/3\/lrand48) - generate uniformly distributed pseudo-random numbers\n- [lrand48\\_r](https:\/\/manual.cs50.io\/3\/lrand48_r) - generate uniformly distributed pseudo-random numbers r...\n- [malloc](https:\/\/manual.cs50.io\/3\/malloc) - allocate and free dynamic memory allocate memory dynamically\n- [MB\\_CUR\\_MAX](https:\/\/manual.cs50.io\/3\/MB_CUR_MAX) - maximum length of a multibyte character in the current...\n- [mblen](https:\/\/manual.cs50.io\/3\/mblen) - determine number of bytes in next multibyte character\n- [mbstowcs](https:\/\/manual.cs50.io\/3\/mbstowcs) - convert a multibyte string to a wide-character string\n- [mbtowc](https:\/\/manual.cs50.io\/3\/mbtowc) - convert a multibyte sequence to a wide character\n- [memalign](https:\/\/manual.cs50.io\/3\/memalign) - allocate aligned memory\n- [mkdtemp](https:\/\/manual.cs50.io\/3\/mkdtemp) - create a unique temporary directory\n- [mkostemp](https:\/\/manual.cs50.io\/3\/mkostemp) - create a unique temporary file\n- [mkostemps](https:\/\/manual.cs50.io\/3\/mkostemps) - create a unique temporary file\n- [mkstemp](https:\/\/manual.cs50.io\/3\/mkstemp) - create a unique temporary file\n- [mkstemps](https:\/\/manual.cs50.io\/3\/mkstemps) - create a unique temporary file\n- [mktemp](https:\/\/manual.cs50.io\/3\/mktemp) - make a unique temporary filename\n- [mrand48](https:\/\/manual.cs50.io\/3\/mrand48) - generate uniformly distributed pseudo-random numbers\n- [mrand48\\_r](https:\/\/manual.cs50.io\/3\/mrand48_r) - generate uniformly distributed pseudo-random numbers r...\n- [nrand48](https:\/\/manual.cs50.io\/3\/nrand48) - generate uniformly distributed pseudo-random numbers\n- [nrand48\\_r](https:\/\/manual.cs50.io\/3\/nrand48_r) - generate uniformly distributed pseudo-random numbers r...\n- [on\\_exit](https:\/\/manual.cs50.io\/3\/on_exit) - register a function to be called at normal process ter...\n- [posix\\_memalign](https:\/\/manual.cs50.io\/3\/posix_memalign) - allocate aligned memory\n- [posix\\_openpt](https:\/\/manual.cs50.io\/3\/posix_openpt) - open a pseudoterminal device\n- [ptsname](https:\/\/manual.cs50.io\/3\/ptsname) - get the name of the slave pseudoterminal\n- [ptsname\\_r](https:\/\/manual.cs50.io\/3\/ptsname_r) - get the name of the slave pseudoterminal\n- [putenv](https:\/\/manual.cs50.io\/3\/putenv) - change or add an environment variable\n- [pvalloc](https:\/\/manual.cs50.io\/3\/pvalloc) - allocate aligned memory\n- [qecvt](https:\/\/manual.cs50.io\/3\/qecvt) - convert a floating-point number to a string\n- [qecvt\\_r](https:\/\/manual.cs50.io\/3\/qecvt_r) - convert a floating-point number to a string\n- [qfcvt](https:\/\/manual.cs50.io\/3\/qfcvt) - convert a floating-point number to a string\n- [qfcvt\\_r](https:\/\/manual.cs50.io\/3\/qfcvt_r) - convert a floating-point number to a string\n- [qgcvt](https:\/\/manual.cs50.io\/3\/qgcvt) - convert a floating-point number to a string\n- [qsort](https:\/\/manual.cs50.io\/3\/qsort) - sort an array\n- [qsort\\_r](https:\/\/manual.cs50.io\/3\/qsort_r) - sort an array\n- [rand](https:\/\/manual.cs50.io\/3\/rand) - pseudo-random number generator\n- [rand\\_r](https:\/\/manual.cs50.io\/3\/rand_r) - pseudo-random number generator\n- [random](https:\/\/manual.cs50.io\/3\/random) - random number generator generate a pseudorandom number\n- [random\\_r](https:\/\/manual.cs50.io\/3\/random_r) - reentrant random number generator\n- [realloc](https:\/\/manual.cs50.io\/3\/realloc) - allocate and free dynamic memory reallocate memory dynamically\n- [reallocarray](https:\/\/manual.cs50.io\/3\/reallocarray) - allocate and free dynamic memory\n- [rpmatch](https:\/\/manual.cs50.io\/3\/rpmatch) - determine if the answer to a question is affirmative o...\n- [secure\\_getenv](https:\/\/manual.cs50.io\/3\/secure_getenv) - get an environment variable\n- [seed48](https:\/\/manual.cs50.io\/3\/seed48) - generate uniformly distributed pseudo-random numbers\n- [seed48\\_r](https:\/\/manual.cs50.io\/3\/seed48_r) - generate uniformly distributed pseudo-random numbers r...\n- [setenv](https:\/\/manual.cs50.io\/3\/setenv) - change or add an environment variable\n- [setstate](https:\/\/manual.cs50.io\/3\/setstate) - random number generator\n- [setstate\\_r](https:\/\/manual.cs50.io\/3\/setstate_r) - reentrant random number generator\n- [srand](https:\/\/manual.cs50.io\/3\/srand) - pseudo-random number generator\n- [srand48](https:\/\/manual.cs50.io\/3\/srand48) - generate uniformly distributed pseudo-random numbers\n- [srand48\\_r](https:\/\/manual.cs50.io\/3\/srand48_r) - generate uniformly distributed pseudo-random numbers r...\n- [srandom](https:\/\/manual.cs50.io\/3\/srandom) - random number generator seed pseudorandom number generation\n- [srandom\\_r](https:\/\/manual.cs50.io\/3\/srandom_r) - reentrant random number generator\n- [strfromd](https:\/\/manual.cs50.io\/3\/strfromd) - convert a floating-point value into a string\n- [strfromf](https:\/\/manual.cs50.io\/3\/strfromf) - convert a floating-point value into a string\n- [strfroml](https:\/\/manual.cs50.io\/3\/strfroml) - convert a floating-point value into a string\n- [strtod](https:\/\/manual.cs50.io\/3\/strtod) - convert ASCII string to floating-point number\n- [strtof](https:\/\/manual.cs50.io\/3\/strtof) - convert ASCII string to floating-point number\n- [strtol](https:\/\/manual.cs50.io\/3\/strtol) - convert a string to a long integer\n- [strtold](https:\/\/manual.cs50.io\/3\/strtold) - convert ASCII string to floating-point number\n- [strtoll](https:\/\/manual.cs50.io\/3\/strtoll) - convert a string to a long integer\n- [strtoq](https:\/\/manual.cs50.io\/3\/strtoq) - convert a string to a long integer\n- [strtoul](https:\/\/manual.cs50.io\/3\/strtoul) - convert a string to an unsigned long integer\n- [strtoull](https:\/\/manual.cs50.io\/3\/strtoull) - convert a string to an unsigned long integer\n- [strtouq](https:\/\/manual.cs50.io\/3\/strtouq) - convert a string to an unsigned long integer\n- [system](https:\/\/manual.cs50.io\/3\/system) - execute a shell command\n- [unlockpt](https:\/\/manual.cs50.io\/3\/unlockpt) - unlock a pseudoterminal master\/slave pair\n- [unsetenv](https:\/\/manual.cs50.io\/3\/unsetenv) - change or add an environment variable\n- [valloc](https:\/\/manual.cs50.io\/3\/valloc) - allocate aligned memory\n- [wcstombs](https:\/\/manual.cs50.io\/3\/wcstombs) - convert a wide-character string to a multibyte string\n- [wctomb](https:\/\/manual.cs50.io\/3\/wctomb) - convert a wide character to a multibyte sequence\n## [string.h](https:\/\/manual.cs50.io\/#string.h)\n- [bstring](https:\/\/manual.cs50.io\/3\/bstring) - byte string operations\n- [memccpy](https:\/\/manual.cs50.io\/3\/memccpy) - copy memory area\n- [memchr](https:\/\/manual.cs50.io\/3\/memchr) - scan memory for a character\n- [memcmp](https:\/\/manual.cs50.io\/3\/memcmp) - compare memory areas\n- [memcpy](https:\/\/manual.cs50.io\/3\/memcpy) - copy memory area\n- [memfrob](https:\/\/manual.cs50.io\/3\/memfrob) - frobnicate (obfuscate) a memory area\n- [memmem](https:\/\/manual.cs50.io\/3\/memmem) - locate a substring\n- [memmove](https:\/\/manual.cs50.io\/3\/memmove) - copy memory area\n- [mempcpy](https:\/\/manual.cs50.io\/3\/mempcpy) - copy memory area\n- [memrchr](https:\/\/manual.cs50.io\/3\/memrchr) - scan memory for a character\n- [memset](https:\/\/manual.cs50.io\/3\/memset) - fill memory with a constant byte\n- [rawmemchr](https:\/\/manual.cs50.io\/3\/rawmemchr) - scan memory for a character\n- [sigabbrev\\_np](https:\/\/manual.cs50.io\/3\/sigabbrev_np) - return string describing signal\n- [sigdescr\\_np](https:\/\/manual.cs50.io\/3\/sigdescr_np) - return string describing signal\n- [stpcpy](https:\/\/manual.cs50.io\/3\/stpcpy) - copy or catenate a string\n- [stpncpy](https:\/\/manual.cs50.io\/3\/stpncpy) - fill a fixed-size buffer with non-null bytes from a st...\n- [strcasestr](https:\/\/manual.cs50.io\/3\/strcasestr) - locate a substring locate a substring\n- [strcat](https:\/\/manual.cs50.io\/3\/strcat) - copy or catenate a string\n- [strchr](https:\/\/manual.cs50.io\/3\/strchr) - locate character in string\n- [strchrnul](https:\/\/manual.cs50.io\/3\/strchrnul) - locate character in string\n- [strcmp](https:\/\/manual.cs50.io\/3\/strcmp) - compare two strings compare two strings\n- [strcoll](https:\/\/manual.cs50.io\/3\/strcoll) - compare two strings using the current locale\n- [strcpy](https:\/\/manual.cs50.io\/3\/strcpy) - copy or catenate a string copy a string\n- [strcspn](https:\/\/manual.cs50.io\/3\/strcspn) - get length of a prefix substring\n- [strdup](https:\/\/manual.cs50.io\/3\/strdup) - duplicate a string\n- [strdupa](https:\/\/manual.cs50.io\/3\/strdupa) - duplicate a string\n- [strerror](https:\/\/manual.cs50.io\/3\/strerror) - return string describing error number\n- [strerror\\_l](https:\/\/manual.cs50.io\/3\/strerror_l) - return string describing error number\n- [strerror\\_r](https:\/\/manual.cs50.io\/3\/strerror_r) - return string describing error number\n- [strerrordesc\\_np](https:\/\/manual.cs50.io\/3\/strerrordesc_np) - return string describing error number\n- [strerrorname\\_np](https:\/\/manual.cs50.io\/3\/strerrorname_np) - return string describing error number\n- [strfry](https:\/\/manual.cs50.io\/3\/strfry) - randomize a string\n- [strlen](https:\/\/manual.cs50.io\/3\/strlen) - calculate the length of a string calculate the length of a string\n- [strncat](https:\/\/manual.cs50.io\/3\/strncat) - append non-null bytes from a source array to a string,...\n- [strncmp](https:\/\/manual.cs50.io\/3\/strncmp) - compare two strings\n- [strncpy](https:\/\/manual.cs50.io\/3\/strncpy) - fill a fixed-size buffer with non-null bytes from a st...\n- [strndup](https:\/\/manual.cs50.io\/3\/strndup) - duplicate a string\n- [strndupa](https:\/\/manual.cs50.io\/3\/strndupa) - duplicate a string\n- [strnlen](https:\/\/manual.cs50.io\/3\/strnlen) - determine the length of a fixed-size string\n- [strpbrk](https:\/\/manual.cs50.io\/3\/strpbrk) - search a string for any of a set of bytes\n- [strrchr](https:\/\/manual.cs50.io\/3\/strrchr) - locate character in string\n- [strsep](https:\/\/manual.cs50.io\/3\/strsep) - extract token from string\n- [strsignal](https:\/\/manual.cs50.io\/3\/strsignal) - return string describing signal\n- [strspn](https:\/\/manual.cs50.io\/3\/strspn) - get length of a prefix substring\n- [strstr](https:\/\/manual.cs50.io\/3\/strstr) - locate a substring locate a substring\n- [strtok](https:\/\/manual.cs50.io\/3\/strtok) - extract tokens from strings\n- [strtok\\_r](https:\/\/manual.cs50.io\/3\/strtok_r) - extract tokens from strings\n- [strverscmp](https:\/\/manual.cs50.io\/3\/strverscmp) - compare two version strings\n- [strxfrm](https:\/\/manual.cs50.io\/3\/strxfrm) - string transformation\n- [sys\\_siglist](https:\/\/manual.cs50.io\/3\/sys_siglist) - return string describing signal\n- [wmempcpy](https:\/\/manual.cs50.io\/3\/wmempcpy) - copy memory area\n## [strings.h](https:\/\/manual.cs50.io\/#strings.h)\n- [bcmp](https:\/\/manual.cs50.io\/3\/bcmp) - compare byte sequences\n- [bcopy](https:\/\/manual.cs50.io\/3\/bcopy) - copy byte sequence\n- [bzero](https:\/\/manual.cs50.io\/3\/bzero) - zero a byte string\n- [explicit\\_bzero](https:\/\/manual.cs50.io\/3\/explicit_bzero) - zero a byte string\n- [ffs](https:\/\/manual.cs50.io\/3\/ffs) - find first bit set in a word\n- [ffsl](https:\/\/manual.cs50.io\/3\/ffsl) - find first bit set in a word\n- [ffsll](https:\/\/manual.cs50.io\/3\/ffsll) - find first bit set in a word\n- [index](https:\/\/manual.cs50.io\/3\/index) - locate character in string\n- [rindex](https:\/\/manual.cs50.io\/3\/rindex) - locate character in string\n- [strcasecmp](https:\/\/manual.cs50.io\/3\/strcasecmp) - compare two strings ignoring case compare two strings ignoring case\n- [string](https:\/\/manual.cs50.io\/3\/string) - string operations\n- [strncasecmp](https:\/\/manual.cs50.io\/3\/strncasecmp) - compare two strings ignoring case\n## [sys\/ipc.h](https:\/\/manual.cs50.io\/#sys\/ipc.h)\n- [ftok](https:\/\/manual.cs50.io\/3\/ftok) - convert a pathname and a project identifier to a Syste...\n## [sys\/mman.h](https:\/\/manual.cs50.io\/#sys\/mman.h)\n- [madvise](https:\/\/manual.cs50.io\/2\/madvise) - give advice about use of memory\n- [memfd\\_create](https:\/\/manual.cs50.io\/2\/memfd_create) - create an anonymous file\n- [mincore](https:\/\/manual.cs50.io\/2\/mincore) - determine whether pages are resident in memory\n- [mlock](https:\/\/manual.cs50.io\/2\/mlock) - lock and unlock memory\n- [mlock2](https:\/\/manual.cs50.io\/2\/mlock2) - lock and unlock memory\n- [mlockall](https:\/\/manual.cs50.io\/2\/mlockall) - lock and unlock memory\n- [mmap](https:\/\/manual.cs50.io\/2\/mmap) - map or unmap files or devices into memory\n- [mmap64](https:\/\/manual.cs50.io\/3\/mmap64) - map or unmap files or devices into memory\n- [mprotect](https:\/\/manual.cs50.io\/2\/mprotect) - set protection on a region of memory\n- [mremap](https:\/\/manual.cs50.io\/2\/mremap) - remap a virtual memory address\n- [msync](https:\/\/manual.cs50.io\/2\/msync) - synchronize a file with a memory map\n- [munlock](https:\/\/manual.cs50.io\/2\/munlock) - lock and unlock memory\n- [munlockall](https:\/\/manual.cs50.io\/2\/munlockall) - lock and unlock memory\n- [munmap](https:\/\/manual.cs50.io\/2\/munmap) - map or unmap files or devices into memory\n- [pkey\\_alloc](https:\/\/manual.cs50.io\/2\/pkey_alloc) - allocate or free a protection key\n- [pkey\\_free](https:\/\/manual.cs50.io\/2\/pkey_free) - allocate or free a protection key\n- [pkey\\_mprotect](https:\/\/manual.cs50.io\/2\/pkey_mprotect) - set protection on a region of memory\n- [posix\\_madvise](https:\/\/manual.cs50.io\/3\/posix_madvise) - give advice about patterns of memory usage\n- [process\\_madvise](https:\/\/manual.cs50.io\/2\/process_madvise) - give advice about use of memory to a process\n- [remap\\_file\\_pages](https:\/\/manual.cs50.io\/2\/remap_file_pages) - create a nonlinear file mapping\n- [shm\\_open](https:\/\/manual.cs50.io\/3\/shm_open) - create\/open or unlink POSIX shared memory objects\n- [shm\\_unlink](https:\/\/manual.cs50.io\/3\/shm_unlink) - create\/open or unlink POSIX shared memory objects\n## [sys\/msg.h](https:\/\/manual.cs50.io\/#sys\/msg.h)\n- [msgctl](https:\/\/manual.cs50.io\/2\/msgctl) - System V message control operations\n- [msgget](https:\/\/manual.cs50.io\/2\/msgget) - get a System V message queue identifier\n- [msgop](https:\/\/manual.cs50.io\/2\/msgop) - System V message queue operations\n- [msgrcv](https:\/\/manual.cs50.io\/2\/msgrcv) - System V message queue operations\n- [msgsnd](https:\/\/manual.cs50.io\/2\/msgsnd) - System V message queue operations\n## [sys\/resource.h](https:\/\/manual.cs50.io\/#sys\/resource.h)\n- [getpriority](https:\/\/manual.cs50.io\/2\/getpriority) - get\/set program scheduling priority\n- [getrlimit](https:\/\/manual.cs50.io\/2\/getrlimit) - get\/set resource limits\n- [getrusage](https:\/\/manual.cs50.io\/2\/getrusage) - get resource usage\n- [prlimit](https:\/\/manual.cs50.io\/2\/prlimit) - get\/set resource limits\n- [prlimit64](https:\/\/manual.cs50.io\/2\/prlimit64) - get\/set resource limits\n- [setpriority](https:\/\/manual.cs50.io\/2\/setpriority) - get\/set program scheduling priority\n- [setrlimit](https:\/\/manual.cs50.io\/2\/setrlimit) - get\/set resource limits\n- [ugetrlimit](https:\/\/manual.cs50.io\/2\/ugetrlimit) - get\/set resource limits\n- [vlimit](https:\/\/manual.cs50.io\/3\/vlimit) - get\/set resource limits\n- [vtimes](https:\/\/manual.cs50.io\/3\/vtimes) - get resource usage\n## [sys\/select.h](https:\/\/manual.cs50.io\/#sys\/select.h)\n- [\\_newselect](https:\/\/manual.cs50.io\/2\/_newselect) - synchronous I\/O multiplexing\n- [FD\\_CLR](https:\/\/manual.cs50.io\/3\/FD_CLR) - synchronous I\/O multiplexing\n- [FD\\_ISSET](https:\/\/manual.cs50.io\/3\/FD_ISSET) - synchronous I\/O multiplexing\n- [FD\\_SET](https:\/\/manual.cs50.io\/3\/FD_SET) - synchronous I\/O multiplexing\n- [FD\\_ZERO](https:\/\/manual.cs50.io\/3\/FD_ZERO) - synchronous I\/O multiplexing\n- [pselect](https:\/\/manual.cs50.io\/2\/pselect) - synchronous I\/O multiplexing\n- [pselect6](https:\/\/manual.cs50.io\/2\/pselect6) - synchronous I\/O multiplexing\n- [select](https:\/\/manual.cs50.io\/2\/select) - synchronous I\/O multiplexing\n## [sys\/sem.h](https:\/\/manual.cs50.io\/#sys\/sem.h)\n- [semctl](https:\/\/manual.cs50.io\/2\/semctl) - System V semaphore control operations\n- [semget](https:\/\/manual.cs50.io\/2\/semget) - get a System V semaphore set identifier\n- [semop](https:\/\/manual.cs50.io\/2\/semop) - System V semaphore operations\n- [semtimedop](https:\/\/manual.cs50.io\/2\/semtimedop) - System V semaphore operations\n## [sys\/shm.h](https:\/\/manual.cs50.io\/#sys\/shm.h)\n- [shmat](https:\/\/manual.cs50.io\/2\/shmat) - System V shared memory operations\n- [shmctl](https:\/\/manual.cs50.io\/2\/shmctl) - System V shared memory control\n- [shmdt](https:\/\/manual.cs50.io\/2\/shmdt) - System V shared memory operations\n- [shmget](https:\/\/manual.cs50.io\/2\/shmget) - allocates a System V shared memory segment\n- [shmop](https:\/\/manual.cs50.io\/2\/shmop) - System V shared memory operations\n## [sys\/socket.h](https:\/\/manual.cs50.io\/#sys\/socket.h)\n- [accept](https:\/\/manual.cs50.io\/2\/accept) - accept a connection on a socket\n- [accept4](https:\/\/manual.cs50.io\/2\/accept4) - accept a connection on a socket\n- [address\\_families](https:\/\/manual.cs50.io\/7\/address_families) - socket address families (domains)\n- [bind](https:\/\/manual.cs50.io\/2\/bind) - bind a name to a socket\n- [cmsg](https:\/\/manual.cs50.io\/3\/cmsg) - access ancillary data\n- [CMSG\\_ALIGN](https:\/\/manual.cs50.io\/3\/CMSG_ALIGN) - access ancillary data\n- [CMSG\\_DATA](https:\/\/manual.cs50.io\/3\/CMSG_DATA) - access ancillary data\n- [CMSG\\_FIRSTHDR](https:\/\/manual.cs50.io\/3\/CMSG_FIRSTHDR) - access ancillary data\n- [CMSG\\_LEN](https:\/\/manual.cs50.io\/3\/CMSG_LEN) - access ancillary data\n- [CMSG\\_NXTHDR](https:\/\/manual.cs50.io\/3\/CMSG_NXTHDR) - access ancillary data\n- [CMSG\\_SPACE](https:\/\/manual.cs50.io\/3\/CMSG_SPACE) - access ancillary data\n- [connect](https:\/\/manual.cs50.io\/2\/connect) - initiate a connection on a socket\n- [ddp](https:\/\/manual.cs50.io\/7\/ddp) - Linux AppleTalk protocol implementation\n- [getnameinfo](https:\/\/manual.cs50.io\/3\/getnameinfo) - address-to-name translation in protocol-independent ma...\n- [getpeername](https:\/\/manual.cs50.io\/2\/getpeername) - get name of connected peer socket\n- [getsockname](https:\/\/manual.cs50.io\/2\/getsockname) - get socket name\n- [getsockopt](https:\/\/manual.cs50.io\/2\/getsockopt) - get and set options on sockets\n- [inet](https:\/\/manual.cs50.io\/3\/inet) - Internet address manipulation routines\n- [inet\\_addr](https:\/\/manual.cs50.io\/3\/inet_addr) - Internet address manipulation routines\n- [inet\\_aton](https:\/\/manual.cs50.io\/3\/inet_aton) - Internet address manipulation routines\n- [inet\\_lnaof](https:\/\/manual.cs50.io\/3\/inet_lnaof) - Internet address manipulation routines\n- [inet\\_makeaddr](https:\/\/manual.cs50.io\/3\/inet_makeaddr) - Internet address manipulation routines\n- [inet\\_netof](https:\/\/manual.cs50.io\/3\/inet_netof) - Internet address manipulation routines\n- [inet\\_network](https:\/\/manual.cs50.io\/3\/inet_network) - Internet address manipulation routines\n- [inet\\_ntoa](https:\/\/manual.cs50.io\/3\/inet_ntoa) - Internet address manipulation routines\n- [ip](https:\/\/manual.cs50.io\/7\/ip) - Linux IPv4 protocol implementation\n- [ipv6](https:\/\/manual.cs50.io\/7\/ipv6) - Linux IPv6 protocol implementation\n- [listen](https:\/\/manual.cs50.io\/2\/listen) - listen for connections on a socket\n- [packet](https:\/\/manual.cs50.io\/7\/packet) - packet interface on device level\n- [raw](https:\/\/manual.cs50.io\/7\/raw) - Linux IPv4 raw sockets\n- [recv](https:\/\/manual.cs50.io\/2\/recv) - receive a message from a socket\n- [recvfrom](https:\/\/manual.cs50.io\/2\/recvfrom) - receive a message from a socket\n- [recvmmsg](https:\/\/manual.cs50.io\/2\/recvmmsg) - receive multiple messages on a socket\n- [recvmsg](https:\/\/manual.cs50.io\/2\/recvmsg) - receive a message from a socket\n- [send](https:\/\/manual.cs50.io\/2\/send) - send a message on a socket\n- [sendmmsg](https:\/\/manual.cs50.io\/2\/sendmmsg) - send multiple messages on a socket\n- [sendmsg](https:\/\/manual.cs50.io\/2\/sendmsg) - send a message on a socket\n- [sendto](https:\/\/manual.cs50.io\/2\/sendto) - send a message on a socket\n- [setsockopt](https:\/\/manual.cs50.io\/2\/setsockopt) - get and set options on sockets\n- [shutdown](https:\/\/manual.cs50.io\/2\/shutdown) - shut down part of a full-duplex connection\n- [sock\\_diag](https:\/\/manual.cs50.io\/7\/sock_diag) - obtaining information about sockets\n- [sockatmark](https:\/\/manual.cs50.io\/3\/sockatmark) - determine whether socket is at out-of-band mark\n- [socket](https:\/\/manual.cs50.io\/2\/socket) - create an endpoint for communication\n- [socket](https:\/\/manual.cs50.io\/7\/socket) - Linux socket interface\n- [socketpair](https:\/\/manual.cs50.io\/2\/socketpair) - create a pair of connected sockets\n- [tcp](https:\/\/manual.cs50.io\/7\/tcp) - TCP protocol\n- [udp](https:\/\/manual.cs50.io\/7\/udp) - User Datagram Protocol for IPv4\n- [udplite](https:\/\/manual.cs50.io\/7\/udplite) - Lightweight User Datagram Protocol\n- [unix](https:\/\/manual.cs50.io\/7\/unix) - sockets for local interprocess communication\n- [vsock](https:\/\/manual.cs50.io\/7\/vsock) - Linux VSOCK address family\n- [x25](https:\/\/manual.cs50.io\/7\/x25) - ITU-T X.25 \/ ISO\/IEC 8208 protocol interface\n## [sys\/stat.h](https:\/\/manual.cs50.io\/#sys\/stat.h)\n- [chmod](https:\/\/manual.cs50.io\/2\/chmod) - change permissions of a file\n- [fchmod](https:\/\/manual.cs50.io\/2\/fchmod) - change permissions of a file\n- [fchmodat](https:\/\/manual.cs50.io\/2\/fchmodat) - change permissions of a file\n- [fstat](https:\/\/manual.cs50.io\/2\/fstat) - get file status\n- [fstat64](https:\/\/manual.cs50.io\/2\/fstat64) - get file status\n- [fstatat](https:\/\/manual.cs50.io\/2\/fstatat) - get file status\n- [fstatat64](https:\/\/manual.cs50.io\/2\/fstatat64) - get file status\n- [futimens](https:\/\/manual.cs50.io\/3\/futimens) - change file timestamps with nanosecond precision\n- [isfdtype](https:\/\/manual.cs50.io\/3\/isfdtype) - test file type of a file descriptor\n- [lstat](https:\/\/manual.cs50.io\/2\/lstat) - get file status\n- [lstat64](https:\/\/manual.cs50.io\/2\/lstat64) - get file status\n- [mkdir](https:\/\/manual.cs50.io\/2\/mkdir) - create a directory\n- [mkdirat](https:\/\/manual.cs50.io\/2\/mkdirat) - create a directory\n- [mknod](https:\/\/manual.cs50.io\/2\/mknod) - create a special or ordinary file\n- [mknodat](https:\/\/manual.cs50.io\/2\/mknodat) - create a special or ordinary file\n- [newfstatat](https:\/\/manual.cs50.io\/2\/newfstatat) - get file status\n- [oldfstat](https:\/\/manual.cs50.io\/2\/oldfstat) - get file status\n- [oldlstat](https:\/\/manual.cs50.io\/2\/oldlstat) - get file status\n- [oldstat](https:\/\/manual.cs50.io\/2\/oldstat) - get file status\n- [stat](https:\/\/manual.cs50.io\/2\/stat) - get file status\n- [stat64](https:\/\/manual.cs50.io\/2\/stat64) - get file status\n- [statx](https:\/\/manual.cs50.io\/2\/statx) - get file status (extended)\n- [umask](https:\/\/manual.cs50.io\/2\/umask) - set file mode creation mask\n- [utimensat](https:\/\/manual.cs50.io\/2\/utimensat) - change file timestamps with nanosecond precision\n## [sys\/statvfs.h](https:\/\/manual.cs50.io\/#sys\/statvfs.h)\n- [fstatvfs](https:\/\/manual.cs50.io\/3\/fstatvfs) - get filesystem statistics\n- [statvfs](https:\/\/manual.cs50.io\/3\/statvfs) - get filesystem statistics\n## [sys\/time.h](https:\/\/manual.cs50.io\/#sys\/time.h)\n- [adjtime](https:\/\/manual.cs50.io\/3\/adjtime) - correct the time to synchronize the system clock\n- [futimes](https:\/\/manual.cs50.io\/3\/futimes) - change file timestamps\n- [futimesat](https:\/\/manual.cs50.io\/2\/futimesat) - change timestamps of a file relative to a directory fi...\n- [getitimer](https:\/\/manual.cs50.io\/2\/getitimer) - get or set value of an interval timer\n- [gettimeofday](https:\/\/manual.cs50.io\/2\/gettimeofday) - get \/ set time\n- [lutimes](https:\/\/manual.cs50.io\/3\/lutimes) - change file timestamps\n- [setitimer](https:\/\/manual.cs50.io\/2\/setitimer) - get or set value of an interval timer\n- [settimeofday](https:\/\/manual.cs50.io\/2\/settimeofday) - get \/ set time\n- [timeradd](https:\/\/manual.cs50.io\/3\/timeradd) - timeval operations\n- [timerclear](https:\/\/manual.cs50.io\/3\/timerclear) - timeval operations\n- [timercmp](https:\/\/manual.cs50.io\/3\/timercmp) - timeval operations\n- [timerisset](https:\/\/manual.cs50.io\/3\/timerisset) - timeval operations\n- [timersub](https:\/\/manual.cs50.io\/3\/timersub) - timeval operations\n- [TIMESPEC\\_TO\\_TIMEVAL](https:\/\/manual.cs50.io\/3\/TIMESPEC_TO_TIMEVAL) - convert between time structures\n- [TIMEVAL\\_TO\\_TIMESPEC](https:\/\/manual.cs50.io\/3\/TIMEVAL_TO_TIMESPEC) - convert between time structures\n## [sys\/times.h](https:\/\/manual.cs50.io\/#sys\/times.h)\n- [times](https:\/\/manual.cs50.io\/2\/times) - get process times\n## [sys\/types.h](https:\/\/manual.cs50.io\/#sys\/types.h)\n- [bindresvport](https:\/\/manual.cs50.io\/3\/bindresvport) - bind a socket to a privileged IP port\n- [closedir](https:\/\/manual.cs50.io\/3\/closedir) - close a directory\n- [db](https:\/\/manual.cs50.io\/3\/db) - database access methods\n- [dbopen](https:\/\/manual.cs50.io\/3\/dbopen) - database access methods\n- [dirfd](https:\/\/manual.cs50.io\/3\/dirfd) - get directory stream file descriptor\n- [endgrent](https:\/\/manual.cs50.io\/3\/endgrent) - get group file entry\n- [endpwent](https:\/\/manual.cs50.io\/3\/endpwent) - get password file entry\n- [fdopendir](https:\/\/manual.cs50.io\/3\/fdopendir) - open a directory\n- [freeaddrinfo](https:\/\/manual.cs50.io\/3\/freeaddrinfo) - network address and service translation\n- [freehostent](https:\/\/manual.cs50.io\/3\/freehostent) - get network hostnames and addresses\n- [freeifaddrs](https:\/\/manual.cs50.io\/3\/freeifaddrs) - get interface addresses\n- [fts](https:\/\/manual.cs50.io\/3\/fts) - traverse a file hierarchy\n- [fts\\_children](https:\/\/manual.cs50.io\/3\/fts_children) - traverse a file hierarchy\n- [fts\\_close](https:\/\/manual.cs50.io\/3\/fts_close) - traverse a file hierarchy\n- [fts\\_open](https:\/\/manual.cs50.io\/3\/fts_open) - traverse a file hierarchy\n- [fts\\_read](https:\/\/manual.cs50.io\/3\/fts_read) - traverse a file hierarchy\n- [fts\\_set](https:\/\/manual.cs50.io\/3\/fts_set) - traverse a file hierarchy\n- [gai\\_strerror](https:\/\/manual.cs50.io\/3\/gai_strerror) - network address and service translation\n- [getaddrinfo](https:\/\/manual.cs50.io\/3\/getaddrinfo) - network address and service translation\n- [getgrent](https:\/\/manual.cs50.io\/3\/getgrent) - get group file entry\n- [getgrgid](https:\/\/manual.cs50.io\/3\/getgrgid) - get group file entry\n- [getgrgid\\_r](https:\/\/manual.cs50.io\/3\/getgrgid_r) - get group file entry\n- [getgrnam](https:\/\/manual.cs50.io\/3\/getgrnam) - get group file entry\n- [getgrnam\\_r](https:\/\/manual.cs50.io\/3\/getgrnam_r) - get group file entry\n- [getifaddrs](https:\/\/manual.cs50.io\/3\/getifaddrs) - get interface addresses\n- [getipnodebyaddr](https:\/\/manual.cs50.io\/3\/getipnodebyaddr) - get network hostnames and addresses\n- [getipnodebyname](https:\/\/manual.cs50.io\/3\/getipnodebyname) - get network hostnames and addresses\n- [getpw](https:\/\/manual.cs50.io\/3\/getpw) - reconstruct password line entry\n- [getpwent](https:\/\/manual.cs50.io\/3\/getpwent) - get password file entry\n- [getpwnam](https:\/\/manual.cs50.io\/3\/getpwnam) - get password file entry\n- [getpwnam\\_r](https:\/\/manual.cs50.io\/3\/getpwnam_r) - get password file entry\n- [getpwuid](https:\/\/manual.cs50.io\/3\/getpwuid) - get password file entry\n- [getpwuid\\_r](https:\/\/manual.cs50.io\/3\/getpwuid_r) - get password file entry\n- [initgroups](https:\/\/manual.cs50.io\/3\/initgroups) - initialize the supplementary group access list\n- [lseek64](https:\/\/manual.cs50.io\/3\/lseek64) - reposition 64-bit read\/write file offset\n- [mkfifo](https:\/\/manual.cs50.io\/3\/mkfifo) - make a FIFO special file (a named pipe)\n- [mkfifoat](https:\/\/manual.cs50.io\/3\/mkfifoat) - make a FIFO special file (a named pipe)\n- [opendir](https:\/\/manual.cs50.io\/3\/opendir) - open a directory\n- [re\\_comp](https:\/\/manual.cs50.io\/3\/re_comp) - BSD regex functions\n- [re\\_exec](https:\/\/manual.cs50.io\/3\/re_exec) - BSD regex functions\n- [rewinddir](https:\/\/manual.cs50.io\/3\/rewinddir) - reset directory stream\n- [setgrent](https:\/\/manual.cs50.io\/3\/setgrent) - get group file entry\n- [setpwent](https:\/\/manual.cs50.io\/3\/setpwent) - get password file entry\n- [ustat](https:\/\/manual.cs50.io\/2\/ustat) - get filesystem statistics\n## [sys\/uio.h](https:\/\/manual.cs50.io\/#sys\/uio.h)\n- [preadv](https:\/\/manual.cs50.io\/2\/preadv) - read or write data into multiple buffers\n- [preadv2](https:\/\/manual.cs50.io\/2\/preadv2) - read or write data into multiple buffers\n- [process\\_vm\\_readv](https:\/\/manual.cs50.io\/2\/process_vm_readv) - transfer data between process address spaces\n- [process\\_vm\\_writev](https:\/\/manual.cs50.io\/2\/process_vm_writev) - transfer data between process address spaces\n- [pwritev](https:\/\/manual.cs50.io\/2\/pwritev) - read or write data into multiple buffers\n- [pwritev2](https:\/\/manual.cs50.io\/2\/pwritev2) - read or write data into multiple buffers\n- [readv](https:\/\/manual.cs50.io\/2\/readv) - read or write data into multiple buffers\n- [writev](https:\/\/manual.cs50.io\/2\/writev) - read or write data into multiple buffers\n## [sys\/utsname.h](https:\/\/manual.cs50.io\/#sys\/utsname.h)\n- [oldolduname](https:\/\/manual.cs50.io\/2\/oldolduname) - get name and information about current kernel\n- [olduname](https:\/\/manual.cs50.io\/2\/olduname) - get name and information about current kernel\n- [uname](https:\/\/manual.cs50.io\/2\/uname) - get name and information about current kernel\n## [sys\/wait.h](https:\/\/manual.cs50.io\/#sys\/wait.h)\n- [wait](https:\/\/manual.cs50.io\/2\/wait) - wait for process to change state\n- [wait3](https:\/\/manual.cs50.io\/2\/wait3) - wait for process to change state, BSD style\n- [wait4](https:\/\/manual.cs50.io\/2\/wait4) - wait for process to change state, BSD style\n- [waitid](https:\/\/manual.cs50.io\/2\/waitid) - wait for process to change state\n- [waitpid](https:\/\/manual.cs50.io\/2\/waitpid) - wait for process to change state\n## [syslog.h](https:\/\/manual.cs50.io\/#syslog.h)\n- [closelog](https:\/\/manual.cs50.io\/3\/closelog) - send messages to the system logger\n- [openlog](https:\/\/manual.cs50.io\/3\/openlog) - send messages to the system logger\n- [setlogmask](https:\/\/manual.cs50.io\/3\/setlogmask) - set log priority mask\n- [syslog](https:\/\/manual.cs50.io\/3\/syslog) - send messages to the system logger\n- [vsyslog](https:\/\/manual.cs50.io\/3\/vsyslog) - send messages to the system logger\n## [termios.h](https:\/\/manual.cs50.io\/#termios.h)\n- [cfgetispeed](https:\/\/manual.cs50.io\/3\/cfgetispeed) - get and set terminal attributes, line control, get and...\n- [cfgetospeed](https:\/\/manual.cs50.io\/3\/cfgetospeed) - get and set terminal attributes, line control, get and...\n- [cfmakeraw](https:\/\/manual.cs50.io\/3\/cfmakeraw) - get and set terminal attributes, line control, get and...\n- [cfsetispeed](https:\/\/manual.cs50.io\/3\/cfsetispeed) - get and set terminal attributes, line control, get and...\n- [cfsetospeed](https:\/\/manual.cs50.io\/3\/cfsetospeed) - get and set terminal attributes, line control, get and...\n- [cfsetspeed](https:\/\/manual.cs50.io\/3\/cfsetspeed) - get and set terminal attributes, line control, get and...\n- [tcdrain](https:\/\/manual.cs50.io\/3\/tcdrain) - get and set terminal attributes, line control, get and...\n- [tcflow](https:\/\/manual.cs50.io\/3\/tcflow) - get and set terminal attributes, line control, get and...\n- [tcflush](https:\/\/manual.cs50.io\/3\/tcflush) - get and set terminal attributes, line control, get and...\n- [tcgetattr](https:\/\/manual.cs50.io\/3\/tcgetattr) - get and set terminal attributes, line control, get and...\n- [tcgetsid](https:\/\/manual.cs50.io\/3\/tcgetsid) - get session ID\n- [tcsendbreak](https:\/\/manual.cs50.io\/3\/tcsendbreak) - get and set terminal attributes, line control, get and...\n- [tcsetattr](https:\/\/manual.cs50.io\/3\/tcsetattr) - get and set terminal attributes, line control, get and...\n- [termios](https:\/\/manual.cs50.io\/3\/termios) - get and set terminal attributes, line control, get and...\n## [time.h](https:\/\/manual.cs50.io\/#time.h)\n- [asctime](https:\/\/manual.cs50.io\/3\/asctime) - transform date and time to broken-down time or ASCII\n- [asctime\\_r](https:\/\/manual.cs50.io\/3\/asctime_r) - transform date and time to broken-down time or ASCII\n- [clock](https:\/\/manual.cs50.io\/3\/clock) - determine processor time\n- [clock\\_getcpuclockid](https:\/\/manual.cs50.io\/3\/clock_getcpuclockid) - obtain ID of a process CPU-time clock\n- [clock\\_getres](https:\/\/manual.cs50.io\/2\/clock_getres) - clock and time functions\n- [clock\\_gettime](https:\/\/manual.cs50.io\/2\/clock_gettime) - clock and time functions\n- [clock\\_nanosleep](https:\/\/manual.cs50.io\/2\/clock_nanosleep) - high-resolution sleep with specifiable clock\n- [clock\\_settime](https:\/\/manual.cs50.io\/2\/clock_settime) - clock and time functions\n- [ctime](https:\/\/manual.cs50.io\/3\/ctime) - transform date and time to broken-down time or ASCII\n- [ctime\\_r](https:\/\/manual.cs50.io\/3\/ctime_r) - transform date and time to broken-down time or ASCII\n- [daylight](https:\/\/manual.cs50.io\/3\/daylight) - initialize time conversion information\n- [difftime](https:\/\/manual.cs50.io\/3\/difftime) - calculate time difference\n- [dysize](https:\/\/manual.cs50.io\/3\/dysize) - get number of days for a given year\n- [getdate](https:\/\/manual.cs50.io\/3\/getdate) - convert a date-plus-time string to broken-down time\n- [getdate\\_err](https:\/\/manual.cs50.io\/3\/getdate_err) - convert a date-plus-time string to broken-down time\n- [getdate\\_r](https:\/\/manual.cs50.io\/3\/getdate_r) - convert a date-plus-time string to broken-down time\n- [gmtime](https:\/\/manual.cs50.io\/3\/gmtime) - transform date and time to broken-down time or ASCII\n- [gmtime\\_r](https:\/\/manual.cs50.io\/3\/gmtime_r) - transform date and time to broken-down time or ASCII\n- [localtime](https:\/\/manual.cs50.io\/3\/localtime) - transform date and time to broken-down time or ASCII\n- [localtime\\_r](https:\/\/manual.cs50.io\/3\/localtime_r) - transform date and time to broken-down time or ASCII\n- [mktime](https:\/\/manual.cs50.io\/3\/mktime) - transform date and time to broken-down time or ASCII\n- [nanosleep](https:\/\/manual.cs50.io\/2\/nanosleep) - high-resolution sleep\n- [stime](https:\/\/manual.cs50.io\/2\/stime) - set time\n- [strftime](https:\/\/manual.cs50.io\/3\/strftime) - format date and time\n- [strftime\\_l](https:\/\/manual.cs50.io\/3\/strftime_l) - format date and time\n- [strptime](https:\/\/manual.cs50.io\/3\/strptime) - convert a string representation of time to a time tm s...\n- [time](https:\/\/manual.cs50.io\/2\/time) - get time in seconds get time in seconds\n- [timegm](https:\/\/manual.cs50.io\/3\/timegm) - inverses of gmtime and localtime\n- [timelocal](https:\/\/manual.cs50.io\/3\/timelocal) - inverses of gmtime and localtime\n- [timer\\_create](https:\/\/manual.cs50.io\/2\/timer_create) - create a POSIX per-process timer\n- [timer\\_delete](https:\/\/manual.cs50.io\/2\/timer_delete) - delete a POSIX per-process timer\n- [timer\\_getoverrun](https:\/\/manual.cs50.io\/2\/timer_getoverrun) - get overrun count for a POSIX per-process timer\n- [timer\\_gettime](https:\/\/manual.cs50.io\/2\/timer_gettime) - arm\/disarm and fetch state of POSIX per-process timer\n- [timer\\_settime](https:\/\/manual.cs50.io\/2\/timer_settime) - arm\/disarm and fetch state of POSIX per-process timer\n- [timezone](https:\/\/manual.cs50.io\/3\/timezone) - initialize time conversion information\n- [tzname](https:\/\/manual.cs50.io\/3\/tzname) - initialize time conversion information\n- [tzset](https:\/\/manual.cs50.io\/3\/tzset) - initialize time conversion information\n## [ulimit.h](https:\/\/manual.cs50.io\/#ulimit.h)\n- [ulimit](https:\/\/manual.cs50.io\/3\/ulimit) - get and set user limits\n## [unistd.h](https:\/\/manual.cs50.io\/#unistd.h)\n- [\\_Exit](https:\/\/manual.cs50.io\/2\/_Exit) - terminate the calling process\n- [\\_exit](https:\/\/manual.cs50.io\/2\/_exit) - terminate the calling process\n- [\\_llseek](https:\/\/manual.cs50.io\/2\/_llseek) - reposition read\/write file offset\n- [\\_sysctl](https:\/\/manual.cs50.io\/2\/_sysctl) - read\/write system parameters\n- [access](https:\/\/manual.cs50.io\/2\/access) - check user's permissions for a file\n- [acct](https:\/\/manual.cs50.io\/2\/acct) - switch process accounting on or off\n- [alarm](https:\/\/manual.cs50.io\/2\/alarm) - set an alarm clock for delivery of a signal\n- [arch\\_prctl](https:\/\/manual.cs50.io\/2\/arch_prctl) - set architecture-specific thread state\n- [brk](https:\/\/manual.cs50.io\/2\/brk) - change data segment size\n- [capget](https:\/\/manual.cs50.io\/2\/capget) - set\/get capabilities of thread(s)\n- [capset](https:\/\/manual.cs50.io\/2\/capset) - set\/get capabilities of thread(s)\n- [chdir](https:\/\/manual.cs50.io\/2\/chdir) - change working directory\n- [chown](https:\/\/manual.cs50.io\/2\/chown) - change ownership of a file\n- [chown32](https:\/\/manual.cs50.io\/2\/chown32) - change ownership of a file\n- [chroot](https:\/\/manual.cs50.io\/2\/chroot) - change root directory\n- [close](https:\/\/manual.cs50.io\/2\/close) - close a file descriptor\n- [close\\_range](https:\/\/manual.cs50.io\/2\/close_range) - close all file descriptors in a given range\n- [confstr](https:\/\/manual.cs50.io\/3\/confstr) - get configuration dependent string variables\n- [copy\\_file\\_range](https:\/\/manual.cs50.io\/2\/copy_file_range) - Copy a range of data from one file to another\n- [cuserid](https:\/\/manual.cs50.io\/3\/cuserid) - get username\n- [daemon](https:\/\/manual.cs50.io\/3\/daemon) - run in the background\n- [delete\\_module](https:\/\/manual.cs50.io\/2\/delete_module) - unload a kernel module\n- [dup](https:\/\/manual.cs50.io\/2\/dup) - duplicate a file descriptor\n- [dup2](https:\/\/manual.cs50.io\/2\/dup2) - duplicate a file descriptor\n- [dup3](https:\/\/manual.cs50.io\/2\/dup3) - duplicate a file descriptor\n- [eaccess](https:\/\/manual.cs50.io\/3\/eaccess) - check effective user's permissions for a file\n- [encrypt](https:\/\/manual.cs50.io\/3\/encrypt) - encrypt 64-bit messages\n- [encrypt\\_r](https:\/\/manual.cs50.io\/3\/encrypt_r) - encrypt 64-bit messages\n- [endusershell](https:\/\/manual.cs50.io\/3\/endusershell) - get permitted user shells\n- [euidaccess](https:\/\/manual.cs50.io\/3\/euidaccess) - check effective user's permissions for a file\n- [exec](https:\/\/manual.cs50.io\/3\/exec) - execute a file\n- [execl](https:\/\/manual.cs50.io\/3\/execl) - execute a file\n- [execle](https:\/\/manual.cs50.io\/3\/execle) - execute a file\n- [execlp](https:\/\/manual.cs50.io\/3\/execlp) - execute a file\n- [execv](https:\/\/manual.cs50.io\/3\/execv) - execute a file\n- [execve](https:\/\/manual.cs50.io\/2\/execve) - execute program\n- [execveat](https:\/\/manual.cs50.io\/2\/execveat) - execute program relative to a directory file descriptor\n- [execvp](https:\/\/manual.cs50.io\/3\/execvp) - execute a file\n- [execvpe](https:\/\/manual.cs50.io\/3\/execvpe) - execute a file\n- [exit](https:\/\/manual.cs50.io\/2\/exit) - terminate the calling process\n- [exit\\_group](https:\/\/manual.cs50.io\/2\/exit_group) - exit all threads in a process\n- [faccessat](https:\/\/manual.cs50.io\/2\/faccessat) - check user's permissions for a file\n- [faccessat2](https:\/\/manual.cs50.io\/2\/faccessat2) - check user's permissions for a file\n- [fchdir](https:\/\/manual.cs50.io\/2\/fchdir) - change working directory\n- [fchown](https:\/\/manual.cs50.io\/2\/fchown) - change ownership of a file\n- [fchown32](https:\/\/manual.cs50.io\/2\/fchown32) - change ownership of a file\n- [fchownat](https:\/\/manual.cs50.io\/2\/fchownat) - change ownership of a file\n- [fdatasync](https:\/\/manual.cs50.io\/2\/fdatasync) - synchronize a file's in-core state with storage device\n- [fexecve](https:\/\/manual.cs50.io\/3\/fexecve) - execute program specified via file descriptor\n- [finit\\_module](https:\/\/manual.cs50.io\/2\/finit_module) - load a kernel module\n- [fork](https:\/\/manual.cs50.io\/2\/fork) - create a child process\n- [fpathconf](https:\/\/manual.cs50.io\/3\/fpathconf) - get configuration values for files\n- [fsync](https:\/\/manual.cs50.io\/2\/fsync) - synchronize a file's in-core state with storage device\n- [ftruncate](https:\/\/manual.cs50.io\/2\/ftruncate) - truncate a file to a specified length\n- [ftruncate64](https:\/\/manual.cs50.io\/2\/ftruncate64) - truncate a file to a specified length\n- [futex](https:\/\/manual.cs50.io\/2\/futex) - fast user-space locking\n- [get\\_current\\_dir\\_name](https:\/\/manual.cs50.io\/3\/get_current_dir_name) - get current working directory\n- [get\\_robust\\_list](https:\/\/manual.cs50.io\/2\/get_robust_list) - get\/set list of robust futexes\n- [get\\_thread\\_area](https:\/\/manual.cs50.io\/2\/get_thread_area) - manipulate thread-local storage information\n- [getcwd](https:\/\/manual.cs50.io\/2\/getcwd) - get current working directory\n- [getcwd](https:\/\/manual.cs50.io\/3\/getcwd) - get current working directory\n- [getdents](https:\/\/manual.cs50.io\/2\/getdents) - get directory entries\n- [getdents64](https:\/\/manual.cs50.io\/2\/getdents64) - get directory entries\n- [getdomainname](https:\/\/manual.cs50.io\/2\/getdomainname) - get\/set NIS domain name\n- [getdtablesize](https:\/\/manual.cs50.io\/3\/getdtablesize) - get file descriptor table size\n- [getegid](https:\/\/manual.cs50.io\/2\/getegid) - get group identity\n- [getegid32](https:\/\/manual.cs50.io\/2\/getegid32) - get group identity\n- [getentropy](https:\/\/manual.cs50.io\/3\/getentropy) - fill a buffer with random bytes\n- [geteuid](https:\/\/manual.cs50.io\/2\/geteuid) - get user identity\n- [geteuid32](https:\/\/manual.cs50.io\/2\/geteuid32) - get user identity\n- [getgid](https:\/\/manual.cs50.io\/2\/getgid) - get group identity\n- [getgid32](https:\/\/manual.cs50.io\/2\/getgid32) - get group identity\n- [getgroups](https:\/\/manual.cs50.io\/2\/getgroups) - get\/set list of supplementary group IDs\n- [getgroups32](https:\/\/manual.cs50.io\/2\/getgroups32) - get\/set list of supplementary group IDs\n- [gethostid](https:\/\/manual.cs50.io\/3\/gethostid) - get or set the unique identifier of the current host\n- [gethostname](https:\/\/manual.cs50.io\/2\/gethostname) - get\/set hostname\n- [getlogin](https:\/\/manual.cs50.io\/3\/getlogin) - get username\n- [getlogin\\_r](https:\/\/manual.cs50.io\/3\/getlogin_r) - get username\n- [getopt](https:\/\/manual.cs50.io\/3\/getopt) - Parse command-line options\n- [getopt\\_long](https:\/\/manual.cs50.io\/3\/getopt_long) - Parse command-line options\n- [getopt\\_long\\_only](https:\/\/manual.cs50.io\/3\/getopt_long_only) - Parse command-line options\n- [getpagesize](https:\/\/manual.cs50.io\/2\/getpagesize) - get memory page size\n- [getpass](https:\/\/manual.cs50.io\/3\/getpass) - get a password\n- [getpgid](https:\/\/manual.cs50.io\/2\/getpgid) - set\/get process group\n- [getpgrp](https:\/\/manual.cs50.io\/2\/getpgrp) - set\/get process group\n- [getpid](https:\/\/manual.cs50.io\/2\/getpid) - get process identification\n- [getppid](https:\/\/manual.cs50.io\/2\/getppid) - get process identification\n- [getresgid](https:\/\/manual.cs50.io\/2\/getresgid) - get real, effective, and saved user\/group IDs\n- [getresgid32](https:\/\/manual.cs50.io\/2\/getresgid32) - get real, effective, and saved user\/group IDs\n- [getresuid](https:\/\/manual.cs50.io\/2\/getresuid) - get real, effective, and saved user\/group IDs\n- [getresuid32](https:\/\/manual.cs50.io\/2\/getresuid32) - get real, effective, and saved user\/group IDs\n- [getsid](https:\/\/manual.cs50.io\/2\/getsid) - get session ID\n- [gettid](https:\/\/manual.cs50.io\/2\/gettid) - get thread identification\n- [getuid](https:\/\/manual.cs50.io\/2\/getuid) - get user identity\n- [getuid32](https:\/\/manual.cs50.io\/2\/getuid32) - get user identity\n- [getusershell](https:\/\/manual.cs50.io\/3\/getusershell) - get permitted user shells\n- [getwd](https:\/\/manual.cs50.io\/3\/getwd) - get current working directory\n- [group\\_member](https:\/\/manual.cs50.io\/3\/group_member) - test whether a process is in a group\n- [idle](https:\/\/manual.cs50.io\/2\/idle) - make process 0 idle\n- [init\\_module](https:\/\/manual.cs50.io\/2\/init_module) - load a kernel module\n- [io\\_cancel](https:\/\/manual.cs50.io\/2\/io_cancel) - cancel an outstanding asynchronous I\/O operation\n- [io\\_destroy](https:\/\/manual.cs50.io\/2\/io_destroy) - destroy an asynchronous I\/O context\n- [io\\_getevents](https:\/\/manual.cs50.io\/2\/io_getevents) - read asynchronous I\/O events from the completion queue\n- [ioprio\\_get](https:\/\/manual.cs50.io\/2\/ioprio_get) - get\/set I\/O scheduling class and priority\n- [ioprio\\_set](https:\/\/manual.cs50.io\/2\/ioprio_set) - get\/set I\/O scheduling class and priority\n- [ipc](https:\/\/manual.cs50.io\/2\/ipc) - System V IPC system calls\n- [isatty](https:\/\/manual.cs50.io\/3\/isatty) - test whether a file descriptor refers to a terminal\n- [kcmp](https:\/\/manual.cs50.io\/2\/kcmp) - compare two processes to determine if they share a ker...\n- [kexec\\_file\\_load](https:\/\/manual.cs50.io\/2\/kexec_file_load) - load a new kernel for later execution\n- [kexec\\_load](https:\/\/manual.cs50.io\/2\/kexec_load) - load a new kernel for later execution\n- [keyctl](https:\/\/manual.cs50.io\/2\/keyctl) - manipulate the kernel's key management facility\n- [klogctl](https:\/\/manual.cs50.io\/3\/klogctl) - read and\/or clear kernel message ring buffer; set cons...\n- [lchown](https:\/\/manual.cs50.io\/2\/lchown) - change ownership of a file\n- [lchown32](https:\/\/manual.cs50.io\/2\/lchown32) - change ownership of a file\n- [link](https:\/\/manual.cs50.io\/2\/link) - make a new name for a file\n- [linkat](https:\/\/manual.cs50.io\/2\/linkat) - make a new name for a file\n- [llseek](https:\/\/manual.cs50.io\/2\/llseek) - reposition read\/write file offset\n- [lockf](https:\/\/manual.cs50.io\/3\/lockf) - apply, test or remove a POSIX lock on an open file\n- [lookup\\_dcookie](https:\/\/manual.cs50.io\/2\/lookup_dcookie) - return a directory entry's path\n- [lseek](https:\/\/manual.cs50.io\/2\/lseek) - reposition read\/write file offset\n- [membarrier](https:\/\/manual.cs50.io\/2\/membarrier) - issue memory barriers on a set of threads\n- [memfd\\_secret](https:\/\/manual.cs50.io\/2\/memfd_secret) - create an anonymous RAM-based file to access secret me...\n- [mmap2](https:\/\/manual.cs50.io\/2\/mmap2) - map files or devices into memory\n- [modify\\_ldt](https:\/\/manual.cs50.io\/2\/modify_ldt) - get or set a per-process LDT entry\n- [mount\\_setattr](https:\/\/manual.cs50.io\/2\/mount_setattr) - change properties of a mount or mount tree\n- [mq\\_getsetattr](https:\/\/manual.cs50.io\/2\/mq_getsetattr) - get\/set message queue attributes\n- [nice](https:\/\/manual.cs50.io\/2\/nice) - change process priority\n- [openat2](https:\/\/manual.cs50.io\/2\/openat2) - open and possibly create a file (extended)\n- [optarg](https:\/\/manual.cs50.io\/3\/optarg) - Parse command-line options\n- [opterr](https:\/\/manual.cs50.io\/3\/opterr) - Parse command-line options\n- [optind](https:\/\/manual.cs50.io\/3\/optind) - Parse command-line options\n- [optopt](https:\/\/manual.cs50.io\/3\/optopt) - Parse command-line options\n- [pathconf](https:\/\/manual.cs50.io\/3\/pathconf) - get configuration values for files\n- [pause](https:\/\/manual.cs50.io\/2\/pause) - wait for signal\n- [perf\\_event\\_open](https:\/\/manual.cs50.io\/2\/perf_event_open) - set up performance monitoring\n- [pidfd\\_getfd](https:\/\/manual.cs50.io\/2\/pidfd_getfd) - obtain a duplicate of another process's file descriptor\n- [pidfd\\_open](https:\/\/manual.cs50.io\/2\/pidfd_open) - obtain a file descriptor that refers to a process\n- [pidfd\\_send\\_signal](https:\/\/manual.cs50.io\/2\/pidfd_send_signal) - send a signal to a process specified by a file descri...\n- [pipe](https:\/\/manual.cs50.io\/2\/pipe) - create pipe\n- [pipe2](https:\/\/manual.cs50.io\/2\/pipe2) - create pipe\n- [pivot\\_root](https:\/\/manual.cs50.io\/2\/pivot_root) - change the root mount\n- [pread](https:\/\/manual.cs50.io\/2\/pread) - read from or write to a file descriptor at a given offset\n- [pread64](https:\/\/manual.cs50.io\/2\/pread64) - read from or write to a file descriptor at a given offset\n- [profil](https:\/\/manual.cs50.io\/3\/profil) - execution time profile\n- [pwrite](https:\/\/manual.cs50.io\/2\/pwrite) - read from or write to a file descriptor at a given offset\n- [pwrite64](https:\/\/manual.cs50.io\/2\/pwrite64) - read from or write to a file descriptor at a given offset\n- [read](https:\/\/manual.cs50.io\/2\/read) - read from a file descriptor\n- [readdir](https:\/\/manual.cs50.io\/2\/readdir) - read directory entry\n- [readlink](https:\/\/manual.cs50.io\/2\/readlink) - read value of a symbolic link\n- [readlinkat](https:\/\/manual.cs50.io\/2\/readlinkat) - read value of a symbolic link\n- [reboot](https:\/\/manual.cs50.io\/2\/reboot) - reboot or enable\/disable Ctrl-Alt-Del\n- [rmdir](https:\/\/manual.cs50.io\/2\/rmdir) - delete a directory\n- [rt\\_sigqueueinfo](https:\/\/manual.cs50.io\/2\/rt_sigqueueinfo) - queue a signal and data\n- [rt\\_tgsigqueueinfo](https:\/\/manual.cs50.io\/2\/rt_tgsigqueueinfo) - queue a signal and data\n- [s390\\_guarded\\_storage](https:\/\/manual.cs50.io\/2\/s390_guarded_storage) - operations with z\/Architecture guarded storage fac...\n- [s390\\_pci\\_mmio\\_read](https:\/\/manual.cs50.io\/2\/s390_pci_mmio_read) - transfer data to\/from PCI MMIO memory page\n- [s390\\_pci\\_mmio\\_write](https:\/\/manual.cs50.io\/2\/s390_pci_mmio_write) - transfer data to\/from PCI MMIO memory page\n- [s390\\_runtime\\_instr](https:\/\/manual.cs50.io\/2\/s390_runtime_instr) - enable\/disable s390 CPU run-time instrumentation\n- [s390\\_sthyi](https:\/\/manual.cs50.io\/2\/s390_sthyi) - emulate STHYI instruction\n- [sbrk](https:\/\/manual.cs50.io\/2\/sbrk) - change data segment size\n- [sched\\_getattr](https:\/\/manual.cs50.io\/2\/sched_getattr) - set and get scheduling policy and attributes\n- [sched\\_setattr](https:\/\/manual.cs50.io\/2\/sched_setattr) - set and get scheduling policy and attributes\n- [seccomp](https:\/\/manual.cs50.io\/2\/seccomp) - operate on Secure Computing state of the process\n- [set\\_robust\\_list](https:\/\/manual.cs50.io\/2\/set_robust_list) - get\/set list of robust futexes\n- [set\\_thread\\_area](https:\/\/manual.cs50.io\/2\/set_thread_area) - manipulate thread-local storage information\n- [set\\_tid\\_address](https:\/\/manual.cs50.io\/2\/set_tid_address) - set pointer to thread ID\n- [setdomainname](https:\/\/manual.cs50.io\/2\/setdomainname) - get\/set NIS domain name\n- [setegid](https:\/\/manual.cs50.io\/2\/setegid) - set effective user or group ID\n- [seteuid](https:\/\/manual.cs50.io\/2\/seteuid) - set effective user or group ID\n- [setgid](https:\/\/manual.cs50.io\/2\/setgid) - set group identity\n- [setgid32](https:\/\/manual.cs50.io\/2\/setgid32) - set group identity\n- [setgroups](https:\/\/manual.cs50.io\/2\/setgroups) - get\/set list of supplementary group IDs\n- [setgroups32](https:\/\/manual.cs50.io\/2\/setgroups32) - get\/set list of supplementary group IDs\n- [sethostid](https:\/\/manual.cs50.io\/3\/sethostid) - get or set the unique identifier of the current host\n- [sethostname](https:\/\/manual.cs50.io\/2\/sethostname) - get\/set hostname\n- [setkey](https:\/\/manual.cs50.io\/3\/setkey) - encrypt 64-bit messages\n- [setkey\\_r](https:\/\/manual.cs50.io\/3\/setkey_r) - encrypt 64-bit messages\n- [setpgid](https:\/\/manual.cs50.io\/2\/setpgid) - set\/get process group\n- [setpgrp](https:\/\/manual.cs50.io\/2\/setpgrp) - set\/get process group\n- [setregid](https:\/\/manual.cs50.io\/2\/setregid) - set real and\/or effective user or group ID\n- [setregid32](https:\/\/manual.cs50.io\/2\/setregid32) - set real and\/or effective user or group ID\n- [setresgid](https:\/\/manual.cs50.io\/2\/setresgid) - set real, effective, and saved user or group ID\n- [setresgid32](https:\/\/manual.cs50.io\/2\/setresgid32) - set real, effective, and saved user or group ID\n- [setresuid](https:\/\/manual.cs50.io\/2\/setresuid) - set real, effective, and saved user or group ID\n- [setresuid32](https:\/\/manual.cs50.io\/2\/setresuid32) - set real, effective, and saved user or group ID\n- [setreuid](https:\/\/manual.cs50.io\/2\/setreuid) - set real and\/or effective user or group ID\n- [setreuid32](https:\/\/manual.cs50.io\/2\/setreuid32) - set real and\/or effective user or group ID\n- [setsid](https:\/\/manual.cs50.io\/2\/setsid) - creates a session and sets the process group ID\n- [setuid](https:\/\/manual.cs50.io\/2\/setuid) - set user identity\n- [setuid32](https:\/\/manual.cs50.io\/2\/setuid32) - set user identity\n- [setup](https:\/\/manual.cs50.io\/2\/setup) - setup devices and filesystems, mount root filesystem\n- [setusershell](https:\/\/manual.cs50.io\/3\/setusershell) - get permitted user shells\n- [sgetmask](https:\/\/manual.cs50.io\/2\/sgetmask) - manipulation of signal mask (obsolete)\n- [sleep](https:\/\/manual.cs50.io\/3\/sleep) - sleep for a specified number of seconds\n- [socketcall](https:\/\/manual.cs50.io\/2\/socketcall) - socket system calls\n- [spu\\_create](https:\/\/manual.cs50.io\/2\/spu_create) - create a new spu context\n- [spu\\_run](https:\/\/manual.cs50.io\/2\/spu_run) - execute an SPU context\n- [ssetmask](https:\/\/manual.cs50.io\/2\/ssetmask) - manipulation of signal mask (obsolete)\n- [subpage\\_prot](https:\/\/manual.cs50.io\/2\/subpage_prot) - define a subpage protection for an address range\n- [swab](https:\/\/manual.cs50.io\/3\/swab) - swap adjacent bytes\n- [symlink](https:\/\/manual.cs50.io\/2\/symlink) - make a new name for a file\n- [symlinkat](https:\/\/manual.cs50.io\/2\/symlinkat) - make a new name for a file\n- [sync](https:\/\/manual.cs50.io\/2\/sync) - commit filesystem caches to disk\n- [syncfs](https:\/\/manual.cs50.io\/2\/syncfs) - commit filesystem caches to disk\n- [syscall](https:\/\/manual.cs50.io\/2\/syscall) - indirect system call\n- [sysconf](https:\/\/manual.cs50.io\/3\/sysconf) - get configuration information at run time\n- [sysctl](https:\/\/manual.cs50.io\/2\/sysctl) - read\/write system parameters\n- [syslog](https:\/\/manual.cs50.io\/2\/syslog) - read and\/or clear kernel message ring buffer; set cons...\n- [tcgetpgrp](https:\/\/manual.cs50.io\/3\/tcgetpgrp) - get and set terminal foreground process group\n- [tcsetpgrp](https:\/\/manual.cs50.io\/3\/tcsetpgrp) - get and set terminal foreground process group\n- [tgkill](https:\/\/manual.cs50.io\/2\/tgkill) - send a signal to a thread\n- [tkill](https:\/\/manual.cs50.io\/2\/tkill) - send a signal to a thread\n- [truncate](https:\/\/manual.cs50.io\/2\/truncate) - truncate a file to a specified length\n- [truncate64](https:\/\/manual.cs50.io\/2\/truncate64) - truncate a file to a specified length\n- [ttyname](https:\/\/manual.cs50.io\/3\/ttyname) - return name of a terminal\n- [ttyname\\_r](https:\/\/manual.cs50.io\/3\/ttyname_r) - return name of a terminal\n- [ualarm](https:\/\/manual.cs50.io\/3\/ualarm) - schedule signal after given number of microseconds\n- [unlink](https:\/\/manual.cs50.io\/2\/unlink) - delete a name and possibly the file it refers to\n- [unlinkat](https:\/\/manual.cs50.io\/2\/unlinkat) - delete a name and possibly the file it refers to\n- [uselib](https:\/\/manual.cs50.io\/2\/uselib) - load shared library\n- [userfaultfd](https:\/\/manual.cs50.io\/2\/userfaultfd) - create a file descriptor for handling page faults in u...\n- [usleep](https:\/\/manual.cs50.io\/3\/usleep) - suspend execution for microsecond intervals\n- [vfork](https:\/\/manual.cs50.io\/2\/vfork) - create a child process and block parent\n- [vhangup](https:\/\/manual.cs50.io\/2\/vhangup) - virtually hangup the current terminal\n- [write](https:\/\/manual.cs50.io\/2\/write) - write to a file descriptor\n## [utime.h](https:\/\/manual.cs50.io\/#utime.h)\n- [utime](https:\/\/manual.cs50.io\/2\/utime) - change file last access and modification times\n- [utimes](https:\/\/manual.cs50.io\/2\/utimes) - change file last access and modification times\n## [utmpx.h](https:\/\/manual.cs50.io\/#utmpx.h)\n- [getutmp](https:\/\/manual.cs50.io\/3\/getutmp) - copy utmp structure to utmpx, and vice versa\n- [getutmpx](https:\/\/manual.cs50.io\/3\/getutmpx) - copy utmp structure to utmpx, and vice versa\n## [wchar.h](https:\/\/manual.cs50.io\/#wchar.h)\n- [btowc](https:\/\/manual.cs50.io\/3\/btowc) - convert single byte to wide character\n- [fgetws](https:\/\/manual.cs50.io\/3\/fgetws) - read a wide-character string from a FILE stream\n- [fputws](https:\/\/manual.cs50.io\/3\/fputws) - write a wide-character string to a FILE stream\n- [fwide](https:\/\/manual.cs50.io\/3\/fwide) - set and determine the orientation of a FILE stream\n- [getwchar](https:\/\/manual.cs50.io\/3\/getwchar) - read a wide character from standard input\n- [mbrlen](https:\/\/manual.cs50.io\/3\/mbrlen) - determine number of bytes in next multibyte character\n- [mbrtowc](https:\/\/manual.cs50.io\/3\/mbrtowc) - convert a multibyte sequence to a wide character\n- [mbsinit](https:\/\/manual.cs50.io\/3\/mbsinit) - test for initial shift state\n- [mbsnrtowcs](https:\/\/manual.cs50.io\/3\/mbsnrtowcs) - convert a multibyte string to a wide-character string\n- [mbsrtowcs](https:\/\/manual.cs50.io\/3\/mbsrtowcs) - convert a multibyte string to a wide-character string ...\n- [putwchar](https:\/\/manual.cs50.io\/3\/putwchar) - write a wide character to standard output\n- [ungetwc](https:\/\/manual.cs50.io\/3\/ungetwc) - push back a wide character onto a FILE stream\n- [wcpcpy](https:\/\/manual.cs50.io\/3\/wcpcpy) - copy a wide-character string, returning a pointer to i...\n- [wcpncpy](https:\/\/manual.cs50.io\/3\/wcpncpy) - copy a fixed-size string of wide characters, returning...\n- [wcrtomb](https:\/\/manual.cs50.io\/3\/wcrtomb) - convert a wide character to a multibyte sequence\n- [wcscasecmp](https:\/\/manual.cs50.io\/3\/wcscasecmp) - compare two wide-character strings, ignoring case\n- [wcscat](https:\/\/manual.cs50.io\/3\/wcscat) - concatenate two wide-character strings\n- [wcschr](https:\/\/manual.cs50.io\/3\/wcschr) - search a wide character in a wide-character string\n- [wcscmp](https:\/\/manual.cs50.io\/3\/wcscmp) - compare two wide-character strings\n- [wcscpy](https:\/\/manual.cs50.io\/3\/wcscpy) - copy a wide-character string\n- [wcscspn](https:\/\/manual.cs50.io\/3\/wcscspn) - search a wide-character string for any of a set of wid...\n- [wcsdup](https:\/\/manual.cs50.io\/3\/wcsdup) - duplicate a wide-character string\n- [wcslen](https:\/\/manual.cs50.io\/3\/wcslen) - determine the length of a wide-character string\n- [wcsncasecmp](https:\/\/manual.cs50.io\/3\/wcsncasecmp) - compare two fixed-size wide-character strings, ignorin...\n- [wcsncat](https:\/\/manual.cs50.io\/3\/wcsncat) - concatenate two wide-character strings\n- [wcsncmp](https:\/\/manual.cs50.io\/3\/wcsncmp) - compare two fixed-size wide-character strings\n- [wcsncpy](https:\/\/manual.cs50.io\/3\/wcsncpy) - copy a fixed-size string of wide characters\n- [wcsnlen](https:\/\/manual.cs50.io\/3\/wcsnlen) - determine the length of a fixed-size wide-character st...\n- [wcsnrtombs](https:\/\/manual.cs50.io\/3\/wcsnrtombs) - convert a wide-character string to a multibyte string\n- [wcspbrk](https:\/\/manual.cs50.io\/3\/wcspbrk) - search a wide-character string for any of a set of wid...\n- [wcsrchr](https:\/\/manual.cs50.io\/3\/wcsrchr) - search a wide character in a wide-character string\n- [wcsrtombs](https:\/\/manual.cs50.io\/3\/wcsrtombs) - convert a wide-character string to a multibyte string\n- [wcsspn](https:\/\/manual.cs50.io\/3\/wcsspn) - get length of a prefix wide-character substring\n- [wcsstr](https:\/\/manual.cs50.io\/3\/wcsstr) - locate a substring in a wide-character string\n- [wcstok](https:\/\/manual.cs50.io\/3\/wcstok) - split wide-character string into tokens\n- [wcswidth](https:\/\/manual.cs50.io\/3\/wcswidth) - determine columns needed for a fixed-size wide-charact...\n- [wctob](https:\/\/manual.cs50.io\/3\/wctob) - try to represent a wide character as a single byte\n- [wcwidth](https:\/\/manual.cs50.io\/3\/wcwidth) - determine columns needed for a wide character\n- [wmemchr](https:\/\/manual.cs50.io\/3\/wmemchr) - search a wide character in a wide-character array\n- [wmemcmp](https:\/\/manual.cs50.io\/3\/wmemcmp) - compare two arrays of wide-characters\n- [wmemcpy](https:\/\/manual.cs50.io\/3\/wmemcpy) - copy an array of wide-characters\n- [wmemmove](https:\/\/manual.cs50.io\/3\/wmemmove) - copy an array of wide-characters\n- [wmemset](https:\/\/manual.cs50.io\/3\/wmemset) - fill an array of wide-characters with a constant wide ...\n## [wctype.h](https:\/\/manual.cs50.io\/#wctype.h)\n- [iswalnum](https:\/\/manual.cs50.io\/3\/iswalnum) - test for alphanumeric wide character\n- [iswalpha](https:\/\/manual.cs50.io\/3\/iswalpha) - test for alphabetic wide character\n- [iswblank](https:\/\/manual.cs50.io\/3\/iswblank) - test for whitespace wide character\n- [iswcntrl](https:\/\/manual.cs50.io\/3\/iswcntrl) - test for control wide character\n- [iswctype](https:\/\/manual.cs50.io\/3\/iswctype) - wide-character classification\n- [iswdigit](https:\/\/manual.cs50.io\/3\/iswdigit) - test for decimal digit wide character\n- [iswgraph](https:\/\/manual.cs50.io\/3\/iswgraph) - test for graphic wide character\n- [iswlower](https:\/\/manual.cs50.io\/3\/iswlower) - test for lowercase wide character\n- [iswprint](https:\/\/manual.cs50.io\/3\/iswprint) - test for printing wide character\n- [iswpunct](https:\/\/manual.cs50.io\/3\/iswpunct) - test for punctuation or symbolic wide character\n- [iswspace](https:\/\/manual.cs50.io\/3\/iswspace) - test for whitespace wide character\n- [iswupper](https:\/\/manual.cs50.io\/3\/iswupper) - test for uppercase wide character\n- [iswxdigit](https:\/\/manual.cs50.io\/3\/iswxdigit) - test for hexadecimal digit wide character\n- [towctrans](https:\/\/manual.cs50.io\/3\/towctrans) - wide-character transliteration\n- [towlower](https:\/\/manual.cs50.io\/3\/towlower) - convert a wide character to lowercase\n- [towlower\\_l](https:\/\/manual.cs50.io\/3\/towlower_l) - convert a wide character to lowercase\n- [towupper](https:\/\/manual.cs50.io\/3\/towupper) - convert a wide character to uppercase\n- [towupper\\_l](https:\/\/manual.cs50.io\/3\/towupper_l) - convert a wide character to uppercase\n- [wctrans](https:\/\/manual.cs50.io\/3\/wctrans) - wide-character translation mapping\n- [wctype](https:\/\/manual.cs50.io\/3\/wctype) - wide-character classification\n## [wordexp.h](https:\/\/manual.cs50.io\/#wordexp.h)\n- [wordexp](https:\/\/manual.cs50.io\/3\/wordexp) - perform word expansion like a posix-shell\n- [wordfree](https:\/\/manual.cs50.io\/3\/wordfree) - perform word expansion like a posix-shell","meta_canonical":null}

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URL	https://manual.cs50.io/
Last Crawled	2026-04-05 20:05:02 (6 days ago)
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Boilerpipe Text	Manual pages for the C standard library, the C POSIX library, and the CS50 Library for those less comfortable . aio.h aio_cancel - cancel an outstanding asynchronous I/O request aio_error - get error status of asynchronous I/O operation aio_fsync - asynchronous file synchronization aio_init - asynchronous I/O initialization aio_read - asynchronous read aio_return - get return status of asynchronous I/O operation aio_suspend - wait for asynchronous I/O operation or timeout aio_write - asynchronous write lio_listio - initiate a list of I/O requests arpa/inet.h byteorder - convert values between host and network byte order htonl - convert values between host and network byte order htons - convert values between host and network byte order inet_net_ntop - Internet network number conversion inet_net_pton - Internet network number conversion inet_ntop - convert IPv4 and IPv6 addresses from binary to text form inet_pton - convert IPv4 and IPv6 addresses from text to binary form ntohl - convert values between host and network byte order ntohs - convert values between host and network byte order assert.h _Static_assert - fail compilation if assertion is false assert - abort the program if assertion is false assert_perror - test errnum and abort static_assert - fail compilation if assertion is false complex.h cabs - absolute value of a complex number cabsf - absolute value of a complex number cabsl - absolute value of a complex number cacos - complex arc cosine cacosf - complex arc cosine cacosh - complex arc hyperbolic cosine cacoshf - complex arc hyperbolic cosine cacoshl - complex arc hyperbolic cosine cacosl - complex arc cosine carg - calculate the complex argument cargf - calculate the complex argument cargl - calculate the complex argument casin - complex arc sine casinf - complex arc sine casinh - complex arc sine hyperbolic casinhf - complex arc sine hyperbolic casinhl - complex arc sine hyperbolic casinl - complex arc sine catan - complex arc tangents catanf - complex arc tangents catanh - complex arc tangents hyperbolic catanhf - complex arc tangents hyperbolic catanhl - complex arc tangents hyperbolic catanl - complex arc tangents ccos - complex cosine function ccosf - complex cosine function ccosh - complex hyperbolic cosine ccoshf - complex hyperbolic cosine ccoshl - complex hyperbolic cosine ccosl - complex cosine function cexp - complex exponential function cexp2 - base-2 exponent of a complex number cexp2f - base-2 exponent of a complex number cexp2l - base-2 exponent of a complex number cexpf - complex exponential function cexpl - complex exponential function cimag - get imaginary part of a complex number cimagf - get imaginary part of a complex number cimagl - get imaginary part of a complex number clog - natural logarithm of a complex number clog10 - base-10 logarithm of a complex number clog10f - base-10 logarithm of a complex number clog10l - base-10 logarithm of a complex number clog2 - base-2 logarithm of a complex number clog2f - base-2 logarithm of a complex number clog2l - base-2 logarithm of a complex number clogf - natural logarithm of a complex number clogl - natural logarithm of a complex number complex - basics of complex mathematics conj - calculate the complex conjugate conjf - calculate the complex conjugate conjl - calculate the complex conjugate cpow - complex power function cpowf - complex power function cpowl - complex power function cproj - project into Riemann Sphere cprojf - project into Riemann Sphere cprojl - project into Riemann Sphere creal - get real part of a complex number crealf - get real part of a complex number creall - get real part of a complex number csin - complex sine function csinf - complex sine function csinh - complex hyperbolic sine csinhf - complex hyperbolic sine csinhl - complex hyperbolic sine csinl - complex sine function csqrt - complex square root csqrtf - complex square root csqrtl - complex square root ctan - complex tangent function ctanf - complex tangent function ctanh - complex hyperbolic tangent ctanhf - complex hyperbolic tangent ctanhl - complex hyperbolic tangent ctanl - complex tangent function get_char - prompts user for a line of text from stdin and returns... prompt a user for a char get_double - prompts user for a line of text from stdin and returns... prompt a user for a double get_float - prompts user for a line of text from stdin and returns... prompt a user for a float get_int - prompts user for a line of text from stdin and returns... prompt a user for an int get_long - prompts user for a line of text from stdin and returns... prompt a user for an long get_long_long - prompts user for a line of text from stdin and returns... get_string - prompts user for a line of text from stdin and returns... prompt a user for a string ctype.h isalnum - character classification functions check whether a character is alphanumeric isalnum_l - character classification functions isalpha - character classification functions check whether a character is alphabetical isalpha_l - character classification functions isascii - character classification functions isascii_l - character classification functions isblank - character classification functions check whether a character is blank (i.e., a space or tab) isblank_l - character classification functions iscntrl - character classification functions iscntrl_l - character classification functions isdigit - character classification functions check whether a character is a digit isdigit_l - character classification functions isgraph - character classification functions isgraph_l - character classification functions islower - character classification functions check whether a character is lowercase islower_l - character classification functions isprint - character classification functions isprint_l - character classification functions ispunct - character classification functions check whether a character is punctuation ispunct_l - character classification functions isspace - character classification functions check whether a character is whitespace (e.g., a newline, space, or tab) isspace_l - character classification functions isupper - character classification functions check whether a character is uppercase isupper_l - character classification functions isxdigit - character classification functions isxdigit_l - character classification functions toascii - convert character to ASCII tolower - convert uppercase or lowercase convert a char to lowercase tolower_l - convert uppercase or lowercase toupper - convert uppercase or lowercase convert a char to uppercase toupper_l - convert uppercase or lowercase dirent.h alphasort - scan a directory for matching entries getdirentries - get directory entries in a filesystem-independent format readdir - read a directory readdir_r - read a directory scandir - scan a directory for matching entries scandirat - scan a directory for matching entries seekdir - set the position of the next readdir() call in the dir... telldir - return current location in directory stream versionsort - scan a directory for matching entries dlfcn.h dladdr - translate address to symbolic information dladdr1 - translate address to symbolic information dlclose - open and close a shared object dlerror - obtain error diagnostic for functions in the dlopen API dlmopen - open and close a shared object dlopen - open and close a shared object dlsym - obtain address of a symbol in a shared object or execu... dlvsym - obtain address of a symbol in a shared object or execu... errno.h errno - number of last error program_invocation_name - obtain name used to invoke calling program program_invocation_short_name - obtain name used to invoke calling program fcntl.h arm_fadvise - predeclare an access pattern for file data arm_fadvise64_64 - predeclare an access pattern for file data arm_sync_file_range - sync a file segment with disk creat - open and possibly create a file fadvise64 - predeclare an access pattern for file data fadvise64_64 - predeclare an access pattern for file data fallocate - manipulate file space fcntl - manipulate file descriptor fcntl64 - manipulate file descriptor name_to_handle_at - obtain handle for a pathname and open file via a handle open - open and possibly create a file open_by_handle_at - obtain handle for a pathname and open file via a handle openat - open and possibly create a file posix_fadvise - predeclare an access pattern for file data posix_fallocate - allocate file space readahead - initiate file readahead into page cache splice - splice data to/from a pipe sync_file_range - sync a file segment with disk sync_file_range2 - sync a file segment with disk tee - duplicating pipe content vmsplice - splice user pages to/from a pipe fenv.h feclearexcept - floating-point rounding and exception handling fedisableexcept - floating-point rounding and exception handling feenableexcept - floating-point rounding and exception handling fegetenv - floating-point rounding and exception handling fegetexcept - floating-point rounding and exception handling fegetexceptflag - floating-point rounding and exception handling fegetround - floating-point rounding and exception handling feholdexcept - floating-point rounding and exception handling fenv - floating-point rounding and exception handling feraiseexcept - floating-point rounding and exception handling fesetenv - floating-point rounding and exception handling fesetexceptflag - floating-point rounding and exception handling fesetround - floating-point rounding and exception handling fetestexcept - floating-point rounding and exception handling feupdateenv - floating-point rounding and exception handling fmtmsg.h addseverity - introduce new severity classes fmtmsg - print formatted error messages fnmatch.h fnmatch - match filename or pathname ftw.h ftw - file tree walk nftw - file tree walk glob.h glob - find pathnames matching a pattern, free memory from gl... globfree - find pathnames matching a pattern, free memory from gl... grp.h fgetgrent_r - get group file entry reentrantly getgrent_r - get group file entry reentrantly getgrouplist - get list of groups to which a user belongs putgrent - write a group database entry to a file iconv.h iconv - perform character set conversion iconv_close - deallocate descriptor for character set conversion iconv_open - allocate descriptor for character set conversion inttypes.h strtoimax - convert string to integer strtoumax - convert string to integer langinfo.h nl_langinfo - query language and locale information nl_langinfo_l - query language and locale information libgen.h basename - parse pathname components dirname - parse pathname components limits.h MB_LEN_MAX - maximum multibyte length of a character across all loc... realpath - return the canonicalized absolute pathname locale.h duplocale - duplicate a locale object freelocale - create, modify, and free a locale object locale - description of multilanguage support localeconv - get numeric formatting information newlocale - create, modify, and free a locale object setlocale - set the current locale uselocale - set/get the locale for the calling thread math.h acos - arc cosine function acosf - arc cosine function acosh - inverse hyperbolic cosine function acoshf - inverse hyperbolic cosine function acoshl - inverse hyperbolic cosine function acosl - arc cosine function asin - arc sine function asinf - arc sine function asinh - inverse hyperbolic sine function asinhf - inverse hyperbolic sine function asinhl - inverse hyperbolic sine function asinl - arc sine function atan - arc tangent function atan2 - arc tangent function of two variables atan2f - arc tangent function of two variables atan2l - arc tangent function of two variables atanf - arc tangent function atanh - inverse hyperbolic tangent function atanhf - inverse hyperbolic tangent function atanhl - inverse hyperbolic tangent function atanl - arc tangent function cbrt - cube root function cbrtf - cube root function cbrtl - cube root function ceil - ceiling function: smallest integral value not less tha... calculate the ceiling of a number ceilf - ceiling function: smallest integral value not less tha... ceill - ceiling function: smallest integral value not less tha... copysign - copy sign of a number copysignf - copy sign of a number copysignl - copy sign of a number cos - cosine function cosf - cosine function cosh - hyperbolic cosine function coshf - hyperbolic cosine function coshl - hyperbolic cosine function cosl - cosine function drem - floating-point remainder function dremf - floating-point remainder function dreml - floating-point remainder function erf - error function erfc - complementary error function erfcf - complementary error function erfcl - complementary error function erff - error function erfl - error function exp - base-e exponential function exp10 - base-10 exponential function exp10f - base-10 exponential function exp10l - base-10 exponential function exp2 - base-2 exponential function exp2f - base-2 exponential function exp2l - base-2 exponential function expf - base-e exponential function expl - base-e exponential function expm1 - exponential minus 1 expm1f - exponential minus 1 expm1l - exponential minus 1 fabs - absolute value of floating-point number fabsf - absolute value of floating-point number fabsl - absolute value of floating-point number fdim - positive difference fdimf - positive difference fdiml - positive difference finite - BSD floating-point classification functions finitef - BSD floating-point classification functions finitel - BSD floating-point classification functions floor - largest integral value not greater than argument calculate the floor of a number floorf - largest integral value not greater than argument floorl - largest integral value not greater than argument fma - floating-point multiply and add fmaf - floating-point multiply and add fmal - floating-point multiply and add fmax - determine maximum of two floating-point numbers fmaxf - determine maximum of two floating-point numbers fmaxl - determine maximum of two floating-point numbers fmin - determine minimum of two floating-point numbers fminf - determine minimum of two floating-point numbers fminl - determine minimum of two floating-point numbers fmod - floating-point remainder function fmodf - floating-point remainder function fmodl - floating-point remainder function fpclassify - floating-point classification macros frexp - convert floating-point number to fractional and integr... frexpf - convert floating-point number to fractional and integr... frexpl - convert floating-point number to fractional and integr... gamma - (logarithm of the) gamma function gammaf - (logarithm of the) gamma function gammal - (logarithm of the) gamma function HUGE_VAL - floating-point constants HUGE_VALF - floating-point constants HUGE_VALL - floating-point constants hypot - Euclidean distance function hypotf - Euclidean distance function hypotl - Euclidean distance function ilogb - get integer exponent of a floating-point value ilogbf - get integer exponent of a floating-point value ilogbl - get integer exponent of a floating-point value INFINITY - floating-point constants isfinite - floating-point classification macros isgreater - floating-point relational tests without exception for NaN isgreaterequal - floating-point relational tests without exception for NaN isinf - floating-point classification macros isinff - BSD floating-point classification functions isinfl - BSD floating-point classification functions isless - floating-point relational tests without exception for NaN islessequal - floating-point relational tests without exception for NaN islessgreater - floating-point relational tests without exception for NaN isnan - floating-point classification macros isnanf - BSD floating-point classification functions isnanl - BSD floating-point classification functions isnormal - floating-point classification macros isunordered - floating-point relational tests without exception for NaN j0 - Bessel functions of the first kind j0f - Bessel functions of the first kind j0l - Bessel functions of the first kind j1 - Bessel functions of the first kind j1f - Bessel functions of the first kind j1l - Bessel functions of the first kind jn - Bessel functions of the first kind jnf - Bessel functions of the first kind jnl - Bessel functions of the first kind ldexp - multiply floating-point number by integral power of 2 ldexpf - multiply floating-point number by integral power of 2 ldexpl - multiply floating-point number by integral power of 2 lgamma - log gamma function lgamma_r - log gamma function lgammaf - log gamma function lgammaf_r - log gamma function lgammal - log gamma function lgammal_r - log gamma function llrint - round to nearest integer llrintf - round to nearest integer llrintl - round to nearest integer llround - round to nearest integer llroundf - round to nearest integer llroundl - round to nearest integer log - natural logarithmic function log10 - base-10 logarithmic function log10f - base-10 logarithmic function log10l - base-10 logarithmic function log1p - logarithm of 1 plus argument log1pf - logarithm of 1 plus argument log1pl - logarithm of 1 plus argument log2 - base-2 logarithmic function calculate the base-2 logarithm of a number log2f - base-2 logarithmic function log2l - base-2 logarithmic function logb - get exponent of a floating-point value logbf - get exponent of a floating-point value logbl - get exponent of a floating-point value logf - natural logarithmic function logl - natural logarithmic function lrint - round to nearest integer lrintf - round to nearest integer lrintl - round to nearest integer lround - round to nearest integer lroundf - round to nearest integer lroundl - round to nearest integer math_error - detecting errors from mathematical functions matherr - SVID math library exception handling modf - extract signed integral and fractional values from flo... modff - extract signed integral and fractional values from flo... modfl - extract signed integral and fractional values from flo... NAN - floating-point constants nan - return 'Not a Number' nanf - return 'Not a Number' nanl - return 'Not a Number' nearbyint - round to nearest integer nearbyintf - round to nearest integer nearbyintl - round to nearest integer nextafter - floating-point number manipulation nextafterf - floating-point number manipulation nextafterl - floating-point number manipulation nextdown - return next floating-point number toward positive/nega... nextdownf - return next floating-point number toward positive/nega... nextdownl - return next floating-point number toward positive/nega... nexttoward - floating-point number manipulation nexttowardf - floating-point number manipulation nexttowardl - floating-point number manipulation nextup - return next floating-point number toward positive/nega... nextupf - return next floating-point number toward positive/nega... nextupl - return next floating-point number toward positive/nega... pow - power functions raise a number to a power pow10 - base-10 power functions pow10f - base-10 power functions pow10l - base-10 power functions powf - power functions powl - power functions remainder - floating-point remainder function remainderf - floating-point remainder function remainderl - floating-point remainder function remquo - remainder and part of quotient remquof - remainder and part of quotient remquol - remainder and part of quotient rint - round to nearest integer rintf - round to nearest integer rintl - round to nearest integer round - round to nearest integer, away from zero round a number to the nearest integer roundf - round to nearest integer, away from zero roundl - round to nearest integer, away from zero scalb - multiply floating-point number by integral power of ra... scalbf - multiply floating-point number by integral power of ra... scalbl - multiply floating-point number by integral power of ra... scalbln - multiply floating-point number by integral power of radix scalblnf - multiply floating-point number by integral power of radix scalblnl - multiply floating-point number by integral power of radix scalbn - multiply floating-point number by integral power of radix scalbnf - multiply floating-point number by integral power of radix scalbnl - multiply floating-point number by integral power of radix signbit - test sign of a real floating-point number signgam - log gamma function significand - get mantissa of floating-point number significandf - get mantissa of floating-point number significandl - get mantissa of floating-point number sin - sine function sincos - calculate sin and cos simultaneously sincosf - calculate sin and cos simultaneously sincosl - calculate sin and cos simultaneously sinf - sine function sinh - hyperbolic sine function sinhf - hyperbolic sine function sinhl - hyperbolic sine function sinl - sine function sqrt - square root function calculate the square root of a number sqrtf - square root function sqrtl - square root function tan - tangent function tanf - tangent function tanh - hyperbolic tangent function tanhf - hyperbolic tangent function tanhl - hyperbolic tangent function tanl - tangent function tgamma - true gamma function tgammaf - true gamma function tgammal - true gamma function trunc - round to integer, toward zero truncf - round to integer, toward zero truncl - round to integer, toward zero y0 - Bessel functions of the second kind y0f - Bessel functions of the second kind y0l - Bessel functions of the second kind y1 - Bessel functions of the second kind y1f - Bessel functions of the second kind y1l - Bessel functions of the second kind yn - Bessel functions of the second kind ynf - Bessel functions of the second kind ynl - Bessel functions of the second kind monetary.h strfmon - convert monetary value to a string strfmon_l - convert monetary value to a string mqueue.h mq_close - close a message queue descriptor mq_getattr - get/set message queue attributes mq_notify - register for notification when a message is available mq_notify - register for notification when a message is available mq_open - open a message queue mq_open - open a message queue mq_receive - receive a message from a message queue mq_send - send a message to a message queue mq_setattr - get/set message queue attributes mq_timedreceive - receive a message from a message queue mq_timedreceive - receive a message from a message queue mq_timedsend - send a message to a message queue mq_timedsend - send a message to a message queue mq_unlink - remove a message queue mq_unlink - remove a message queue net/if.h if_freenameindex - get network interface names and indexes if_indextoname - mappings between network interface names and indexes if_nameindex - get network interface names and indexes if_nametoindex - mappings between network interface names and indexes netdb.h endhostent - get network host entry endnetent - get network entry endnetgrent - handle network group entries endprotoent - get protocol entry endrpcent - get RPC entry endservent - get service entry gai_cancel - asynchronous network address and service translation gai_error - asynchronous network address and service translation gai_suspend - asynchronous network address and service translation getaddrinfo_a - asynchronous network address and service translation gethostbyaddr - get network host entry gethostbyaddr_r - get network host entry gethostbyname - get network host entry gethostbyname2 - get network host entry gethostbyname2_r - get network host entry gethostbyname_r - get network host entry gethostent - get network host entry gethostent_r - get network host entry getnetbyaddr - get network entry getnetbyaddr_r - get network entry (reentrant) getnetbyname - get network entry getnetbyname_r - get network entry (reentrant) getnetent - get network entry getnetent_r - get network entry (reentrant) getnetgrent - handle network group entries getnetgrent_r - handle network group entries getprotobyname - get protocol entry getprotobyname_r - get protocol entry (reentrant) getprotobynumber - get protocol entry getprotobynumber_r - get protocol entry (reentrant) getprotoent - get protocol entry getprotoent_r - get protocol entry (reentrant) getrpcbyname - get RPC entry getrpcbyname_r - get RPC entry (reentrant) getrpcbynumber - get RPC entry getrpcbynumber_r - get RPC entry (reentrant) getrpcent - get RPC entry getrpcent_r - get RPC entry (reentrant) getservbyname - get service entry getservbyname_r - get service entry (reentrant) getservbyport - get service entry getservbyport_r - get service entry (reentrant) getservent - get service entry getservent_r - get service entry (reentrant) h_errno - get network host entry herror - get network host entry hstrerror - get network host entry innetgr - handle network group entries rexec - return stream to a remote command rexec_af - return stream to a remote command sethostent - get network host entry setnetent - get network entry setnetgrent - handle network group entries setprotoent - get protocol entry setrpcent - get RPC entry setservent - get service entry netinet/in.h dn_comp - resolver routines dn_expand - resolver routines res_init - resolver routines res_mkquery - resolver routines res_nclose - resolver routines res_ninit - resolver routines res_nmkquery - resolver routines res_nquery - resolver routines res_nquerydomain - resolver routines res_nsearch - resolver routines res_nsend - resolver routines res_query - resolver routines res_querydomain - resolver routines res_search - resolver routines res_send - resolver routines resolver - resolver routines nl_types.h catclose - open/close a message catalog catgets - get message from a message catalog catopen - open/close a message catalog poll.h poll - wait for some event on a file descriptor ppoll - wait for some event on a file descriptor pthread.h pthread_attr_destroy - initialize and destroy thread attributes object pthread_attr_getaffinity_np - set/get CPU affinity attribute in thread at... pthread_attr_getdetachstate - set/get detach state attribute in thread at... pthread_attr_getguardsize - set/get guard size attribute in thread attrib... pthread_attr_getinheritsched - set/get inherit-scheduler attribute in thr... pthread_attr_getschedparam - set/get scheduling parameter attributes in t... pthread_attr_getschedpolicy - set/get scheduling policy attribute in thre... pthread_attr_getscope - set/get contention scope attribute in thread attr... pthread_attr_getsigmask_np - set/get signal mask attribute in thread attr... pthread_attr_getstack - set/get stack attributes in thread attributes object pthread_attr_getstackaddr - set/get stack address attribute in thread att... pthread_attr_getstacksize - set/get stack size attribute in thread attrib... pthread_attr_init - initialize and destroy thread attributes object pthread_attr_setaffinity_np - set/get CPU affinity attribute in thread at... pthread_attr_setdetachstate - set/get detach state attribute in thread at... pthread_attr_setguardsize - set/get guard size attribute in thread attrib... pthread_attr_setinheritsched - set/get inherit-scheduler attribute in thr... pthread_attr_setschedparam - set/get scheduling parameter attributes in t... pthread_attr_setschedpolicy - set/get scheduling policy attribute in thre... pthread_attr_setscope - set/get contention scope attribute in thread attr... pthread_attr_setsigmask_np - set/get signal mask attribute in thread attr... pthread_attr_setstack - set/get stack attributes in thread attributes object pthread_attr_setstackaddr - set/get stack address attribute in thread att... pthread_attr_setstacksize - set/get stack size attribute in thread attrib... pthread_cancel - send a cancelation request to a thread pthread_cleanup_pop - push and pop thread cancelation clean-up handlers pthread_cleanup_pop_restore_np - push and pop thread cancelation clean-up... pthread_cleanup_push - push and pop thread cancelation clean-up handlers pthread_cleanup_push_defer_np - push and pop thread cancelation clean-up ... pthread_create - create a new thread pthread_detach - detach a thread pthread_equal - compare thread IDs pthread_exit - terminate calling thread pthread_getaffinity_np - set/get CPU affinity of a thread pthread_getattr_default_np - get or set default thread-creation attributes pthread_getattr_np - get attributes of created thread pthread_getconcurrency - set/get the concurrency level pthread_getcpuclockid - retrieve ID of a thread's CPU time clock pthread_getname_np - set/get the name of a thread pthread_getschedparam - set/get scheduling policy and parameters of a thread pthread_join - join with a terminated thread pthread_kill_other_threads_np - terminate all other threads in process pthread_mutex_consistent - make a robust mutex consistent pthread_mutex_consistent_np - make a robust mutex consistent pthread_mutexattr_getpshared - get/set process-shared mutex attribute pthread_mutexattr_getrobust - get and set the robustness attribute of a m... pthread_mutexattr_getrobust_np - get and set the robustness attribute of ... pthread_mutexattr_setpshared - get/set process-shared mutex attribute pthread_mutexattr_setrobust - get and set the robustness attribute of a m... pthread_mutexattr_setrobust_np - get and set the robustness attribute of ... pthread_rwlockattr_getkind_np - set/get the read-write lock kind of the t... pthread_rwlockattr_setkind_np - set/get the read-write lock kind of the t... pthread_self - obtain ID of the calling thread pthread_setaffinity_np - set/get CPU affinity of a thread pthread_setattr_default_np - get or set default thread-creation attributes pthread_setcancelstate - set cancelability state and type pthread_setcanceltype - set cancelability state and type pthread_setconcurrency - set/get the concurrency level pthread_setname_np - set/get the name of a thread pthread_setschedparam - set/get scheduling policy and parameters of a thread pthread_setschedprio - set scheduling priority of a thread pthread_spin_destroy - initialize or destroy a spin lock pthread_spin_init - initialize or destroy a spin lock pthread_spin_lock - lock and unlock a spin lock pthread_spin_trylock - lock and unlock a spin lock pthread_spin_unlock - lock and unlock a spin lock pthread_testcancel - request delivery of any pending cancelation request pthread_timedjoin_np - try to join with a terminated thread pthread_tryjoin_np - try to join with a terminated thread pthread_yield - yield the processor pwd.h fgetpwent_r - get passwd file entry reentrantly getpwent_r - get passwd file entry reentrantly regex.h regcomp - POSIX regex functions regerror - POSIX regex functions regex - POSIX regex functions regexec - POSIX regex functions regfree - POSIX regex functions sched.h __clone2 - create a child process clone - create a child process clone2 - create a child process clone3 - create a child process CPU_ALLOC - macros for manipulating CPU sets CPU_ALLOC_SIZE - macros for manipulating CPU sets CPU_AND - macros for manipulating CPU sets CPU_AND_S - macros for manipulating CPU sets CPU_CLR - macros for manipulating CPU sets CPU_CLR_S - macros for manipulating CPU sets CPU_COUNT - macros for manipulating CPU sets CPU_COUNT_S - macros for manipulating CPU sets CPU_EQUAL - macros for manipulating CPU sets CPU_EQUAL_S - macros for manipulating CPU sets CPU_FREE - macros for manipulating CPU sets CPU_ISSET - macros for manipulating CPU sets CPU_ISSET_S - macros for manipulating CPU sets CPU_OR - macros for manipulating CPU sets CPU_OR_S - macros for manipulating CPU sets CPU_SET - macros for manipulating CPU sets CPU_SET_S - macros for manipulating CPU sets CPU_XOR - macros for manipulating CPU sets CPU_XOR_S - macros for manipulating CPU sets CPU_ZERO - macros for manipulating CPU sets CPU_ZERO_S - macros for manipulating CPU sets getcpu - determine CPU and NUMA node on which the calling threa... sched_get_priority_max - get static priority range sched_get_priority_min - get static priority range sched_getaffinity - set and get a thread's CPU affinity mask sched_getcpu - determine CPU on which the calling thread is running sched_getparam - set and get scheduling parameters sched_getscheduler - set and get scheduling policy/parameters sched_rr_get_interval - get the SCHED_RR interval for the named process sched_setaffinity - set and get a thread's CPU affinity mask sched_setparam - set and get scheduling parameters sched_setscheduler - set and get scheduling policy/parameters sched_yield - yield the processor setns - reassociate thread with a namespace unshare - disassociate parts of the process execution context search.h hcreate - hash table management hcreate_r - hash table management hdestroy - hash table management hdestroy_r - hash table management hsearch - hash table management hsearch_r - hash table management insque - insert/remove an item from a queue lfind - linear search of an array lsearch - linear search of an array remque - insert/remove an item from a queue tdelete - manage a binary search tree tdestroy - manage a binary search tree tfind - manage a binary search tree tsearch - manage a binary search tree twalk - manage a binary search tree twalk_r - manage a binary search tree semaphore.h sem_close - close a named semaphore sem_destroy - destroy an unnamed semaphore sem_getvalue - get the value of a semaphore sem_init - initialize an unnamed semaphore sem_open - initialize and open a named semaphore sem_post - unlock a semaphore sem_timedwait - lock a semaphore sem_trywait - lock a semaphore sem_unlink - remove a named semaphore sem_wait - lock a semaphore setjmp.h longjmp - performing a nonlocal goto setjmp - performing a nonlocal goto siglongjmp - performing a nonlocal goto sigsetjmp - performing a nonlocal goto signal.h bsd_signal - signal handling with BSD semantics gsignal - software signal facility kill - send signal to a process killpg - send signal to a process group psiginfo - print signal description psignal - print signal description pthread_kill - send a signal to a thread pthread_sigmask - examine and change mask of blocked signals pthread_sigqueue - queue a signal and data to a thread raise - send a signal to the caller rt_sigaction - examine and change a signal action rt_sigpending - examine pending signals rt_sigprocmask - examine and change blocked signals rt_sigsuspend - wait for a signal rt_sigtimedwait - synchronously wait for queued signals sigaction - examine and change a signal action sigaddset - POSIX signal set operations sigaltstack - set and/or get signal stack context sigandset - POSIX signal set operations sigblock - BSD signal API sigdelset - POSIX signal set operations sigemptyset - POSIX signal set operations sigfillset - POSIX signal set operations siggetmask - BSD signal API sighold - System V signal API sigignore - System V signal API siginterrupt - allow signals to interrupt system calls sigisemptyset - POSIX signal set operations sigismember - POSIX signal set operations sigmask - BSD signal API signal - ANSI C signal handling sigorset - POSIX signal set operations sigpause - atomically release blocked signals and wait for interrupt sigpending - examine pending signals sigprocmask - examine and change blocked signals sigqueue - queue a signal and data to a process sigrelse - System V signal API sigset - System V signal API sigsetmask - BSD signal API sigsetops - POSIX signal set operations sigstack - set and/or get signal stack context sigsuspend - wait for a signal sigtimedwait - synchronously wait for queued signals sigvec - BSD signal API sigwait - wait for a signal sigwaitinfo - synchronously wait for queued signals ssignal - software signal facility sysv_signal - signal handling with System V semantics spawn.h posix_spawn - spawn a process posix_spawnp - spawn a process stdarg.h stdarg - variable argument lists va_arg - variable argument lists va_copy - variable argument lists va_end - variable argument lists va_start - variable argument lists stddef.h offsetof - offset of a structure member wcstoimax - convert wide-character string to integer wcstoumax - convert wide-character string to integer stdio.h __fbufsize - interfaces to stdio FILE structure __flbf - interfaces to stdio FILE structure __fpending - interfaces to stdio FILE structure __fpurge - purge a stream __freadable - interfaces to stdio FILE structure __freading - interfaces to stdio FILE structure __fsetlocking - interfaces to stdio FILE structure __fwritable - interfaces to stdio FILE structure __fwriting - interfaces to stdio FILE structure _flushlbf - interfaces to stdio FILE structure addmntent - get filesystem descriptor file entry asprintf - print to allocated string clearerr - check and reset stream status clearerr_unlocked - nonlocking stdio functions ctermid - get controlling terminal name dprintf - formatted output conversion endmntent - get filesystem descriptor file entry fclose - close a stream close a file fcloseall - close all open streams fdopen - stream open functions feof - check and reset stream status feof_unlocked - nonlocking stdio functions ferror - check and reset stream status ferror_unlocked - nonlocking stdio functions fflush - flush a stream fflush_unlocked - nonlocking stdio functions fgetc - input of characters and strings fgetc_unlocked - nonlocking stdio functions fgetgrent - get group file entry fgetpos - reposition a stream fgetpwent - get password file entry fgets - input of characters and strings fgets_unlocked - nonlocking stdio functions fgetwc - read a wide character from a FILE stream fgetwc_unlocked - nonlocking stdio functions fgetws_unlocked - nonlocking stdio functions fileno - obtain file descriptor of a stdio stream fileno_unlocked - nonlocking stdio functions flockfile - lock FILE for stdio fmemopen - open memory as stream fopen - stream open functions open a file fopencookie - open a custom stream fprintf - formatted output conversion print to a file fpurge - purge a stream fputc - output of characters and strings fputc_unlocked - nonlocking stdio functions fputs - output of characters and strings fputs_unlocked - nonlocking stdio functions fputwc - write a wide character to a FILE stream fputwc_unlocked - nonlocking stdio functions fputws_unlocked - nonlocking stdio functions fread - binary stream input/output read bytes from a file fread_unlocked - nonlocking stdio functions freopen - stream open functions fscanf - input FILE format conversion get input from a file fseek - reposition a stream fseeko - seek to or report file position fsetpos - reposition a stream ftell - reposition a stream ftello - seek to or report file position ftrylockfile - lock FILE for stdio funlockfile - lock FILE for stdio fwprintf - formatted wide-character output conversion fwrite - binary stream input/output write bytes to a file fwrite_unlocked - nonlocking stdio functions getc - input of characters and strings getc_unlocked - nonlocking stdio functions getchar - input of characters and strings getchar_unlocked - nonlocking stdio functions getdelim - delimited string input getline - delimited string input getmntent - get filesystem descriptor file entry getmntent_r - get filesystem descriptor file entry gets - get a string from standard input (DEPRECATED) getw - input and output of words (ints) getwc - read a wide character from a FILE stream getwc_unlocked - nonlocking stdio functions getwchar_unlocked - nonlocking stdio functions hasmntopt - get filesystem descriptor file entry open_memstream - open a dynamic memory buffer stream open_wmemstream - open a dynamic memory buffer stream pclose - pipe stream to or from a process perror - print a system error message popen - pipe stream to or from a process printf - formatted output conversion print to the screen putc - output of characters and strings putc_unlocked - nonlocking stdio functions putchar - output of characters and strings putchar_unlocked - nonlocking stdio functions putpwent - write a password file entry puts - output of characters and strings putw - input and output of words (ints) putwc - write a wide character to a FILE stream putwc_unlocked - nonlocking stdio functions putwchar_unlocked - nonlocking stdio functions remove - remove a file or directory rename - change the name or location of a file renameat - change the name or location of a file renameat2 - change the name or location of a file rewind - reposition a stream scanf - input FILE format conversion get input from a user setbuf - stream buffering operations setbuffer - stream buffering operations setlinebuf - stream buffering operations setmntent - get filesystem descriptor file entry setvbuf - stream buffering operations snprintf - formatted output conversion sprintf - formatted output conversion print to a string sscanf - input string format conversion stderr - standard I/O streams stdin - standard I/O streams stdio - standard input/output library functions stdio_ext - interfaces to stdio FILE structure stdout - standard I/O streams swprintf - formatted wide-character output conversion sys_errlist - print a system error message sys_nerr - print a system error message tempnam - create a name for a temporary file tmpfile - create a temporary file tmpnam - create a name for a temporary file tmpnam_r - create a name for a temporary file ungetc - input of characters and strings unlocked_stdio - nonlocking stdio functions vasprintf - print to allocated string vdprintf - formatted output conversion vfprintf - formatted output conversion vfscanf - input FILE format conversion vfwprintf - formatted wide-character output conversion vprintf - formatted output conversion vscanf - input FILE format conversion vsnprintf - formatted output conversion vsprintf - formatted output conversion vsscanf - input string format conversion vswprintf - formatted wide-character output conversion vwprintf - formatted wide-character output conversion wprintf - formatted wide-character output conversion stdlib.h a64l - convert between long and base-64 abort - cause abnormal process termination abs - compute the absolute value of an integer aligned_alloc - allocate aligned memory arc4random - cryptographically-secure pseudorandom number generator arc4random_buf - cryptographically-secure pseudorandom number generator arc4random_uniform - cryptographically-secure pseudorandom number generator atexit - register a function to be called at normal process ter... atof - convert a string to a double convert a string to a float atoi - convert a string to an integer convert a string to an int atol - convert a string to an integer convert a string to a long atoll - convert a string to an integer atoq - convert a string to an integer bsearch - binary search of a sorted array calloc - allocate and free dynamic memory canonicalize_file_name - return the canonicalized absolute pathname cfree - free allocated memory clearenv - clear the environment div - compute quotient and remainder of an integer division drand48 - generate uniformly distributed pseudo-random numbers drand48_r - generate uniformly distributed pseudo-random numbers r... ecvt - convert a floating-point number to a string ecvt_r - convert a floating-point number to a string erand48 - generate uniformly distributed pseudo-random numbers erand48_r - generate uniformly distributed pseudo-random numbers r... exit - cause normal process termination fcvt - convert a floating-point number to a string fcvt_r - convert a floating-point number to a string free - allocate and free dynamic memory free dynamically allocated memory gcvt - convert a floating-point number to a string getenv - get an environment variable getloadavg - get system load averages getpt - open a new pseudoterminal master getsubopt - parse suboption arguments from a string grantpt - grant access to the slave pseudoterminal imaxabs - compute the absolute value of an integer imaxdiv - compute quotient and remainder of an integer division initstate - random number generator initstate_r - reentrant random number generator jrand48 - generate uniformly distributed pseudo-random numbers jrand48_r - generate uniformly distributed pseudo-random numbers r... l64a - convert between long and base-64 labs - compute the absolute value of an integer lcong48 - generate uniformly distributed pseudo-random numbers lcong48_r - generate uniformly distributed pseudo-random numbers r... ldiv - compute quotient and remainder of an integer division llabs - compute the absolute value of an integer lldiv - compute quotient and remainder of an integer division lrand48 - generate uniformly distributed pseudo-random numbers lrand48_r - generate uniformly distributed pseudo-random numbers r... malloc - allocate and free dynamic memory allocate memory dynamically MB_CUR_MAX - maximum length of a multibyte character in the current... mblen - determine number of bytes in next multibyte character mbstowcs - convert a multibyte string to a wide-character string mbtowc - convert a multibyte sequence to a wide character memalign - allocate aligned memory mkdtemp - create a unique temporary directory mkostemp - create a unique temporary file mkostemps - create a unique temporary file mkstemp - create a unique temporary file mkstemps - create a unique temporary file mktemp - make a unique temporary filename mrand48 - generate uniformly distributed pseudo-random numbers mrand48_r - generate uniformly distributed pseudo-random numbers r... nrand48 - generate uniformly distributed pseudo-random numbers nrand48_r - generate uniformly distributed pseudo-random numbers r... on_exit - register a function to be called at normal process ter... posix_memalign - allocate aligned memory posix_openpt - open a pseudoterminal device ptsname - get the name of the slave pseudoterminal ptsname_r - get the name of the slave pseudoterminal putenv - change or add an environment variable pvalloc - allocate aligned memory qecvt - convert a floating-point number to a string qecvt_r - convert a floating-point number to a string qfcvt - convert a floating-point number to a string qfcvt_r - convert a floating-point number to a string qgcvt - convert a floating-point number to a string qsort - sort an array qsort_r - sort an array rand - pseudo-random number generator rand_r - pseudo-random number generator random - random number generator generate a pseudorandom number random_r - reentrant random number generator realloc - allocate and free dynamic memory reallocate memory dynamically reallocarray - allocate and free dynamic memory rpmatch - determine if the answer to a question is affirmative o... secure_getenv - get an environment variable seed48 - generate uniformly distributed pseudo-random numbers seed48_r - generate uniformly distributed pseudo-random numbers r... setenv - change or add an environment variable setstate - random number generator setstate_r - reentrant random number generator srand - pseudo-random number generator srand48 - generate uniformly distributed pseudo-random numbers srand48_r - generate uniformly distributed pseudo-random numbers r... srandom - random number generator seed pseudorandom number generation srandom_r - reentrant random number generator strfromd - convert a floating-point value into a string strfromf - convert a floating-point value into a string strfroml - convert a floating-point value into a string strtod - convert ASCII string to floating-point number strtof - convert ASCII string to floating-point number strtol - convert a string to a long integer strtold - convert ASCII string to floating-point number strtoll - convert a string to a long integer strtoq - convert a string to a long integer strtoul - convert a string to an unsigned long integer strtoull - convert a string to an unsigned long integer strtouq - convert a string to an unsigned long integer system - execute a shell command unlockpt - unlock a pseudoterminal master/slave pair unsetenv - change or add an environment variable valloc - allocate aligned memory wcstombs - convert a wide-character string to a multibyte string wctomb - convert a wide character to a multibyte sequence string.h bstring - byte string operations memccpy - copy memory area memchr - scan memory for a character memcmp - compare memory areas memcpy - copy memory area memfrob - frobnicate (obfuscate) a memory area memmem - locate a substring memmove - copy memory area mempcpy - copy memory area memrchr - scan memory for a character memset - fill memory with a constant byte rawmemchr - scan memory for a character sigabbrev_np - return string describing signal sigdescr_np - return string describing signal stpcpy - copy or catenate a string stpncpy - fill a fixed-size buffer with non-null bytes from a st... strcasestr - locate a substring locate a substring strcat - copy or catenate a string strchr - locate character in string strchrnul - locate character in string strcmp - compare two strings compare two strings strcoll - compare two strings using the current locale strcpy - copy or catenate a string copy a string strcspn - get length of a prefix substring strdup - duplicate a string strdupa - duplicate a string strerror - return string describing error number strerror_l - return string describing error number strerror_r - return string describing error number strerrordesc_np - return string describing error number strerrorname_np - return string describing error number strfry - randomize a string strlen - calculate the length of a string calculate the length of a string strncat - append non-null bytes from a source array to a string,... strncmp - compare two strings strncpy - fill a fixed-size buffer with non-null bytes from a st... strndup - duplicate a string strndupa - duplicate a string strnlen - determine the length of a fixed-size string strpbrk - search a string for any of a set of bytes strrchr - locate character in string strsep - extract token from string strsignal - return string describing signal strspn - get length of a prefix substring strstr - locate a substring locate a substring strtok - extract tokens from strings strtok_r - extract tokens from strings strverscmp - compare two version strings strxfrm - string transformation sys_siglist - return string describing signal wmempcpy - copy memory area strings.h bcmp - compare byte sequences bcopy - copy byte sequence bzero - zero a byte string explicit_bzero - zero a byte string ffs - find first bit set in a word ffsl - find first bit set in a word ffsll - find first bit set in a word index - locate character in string rindex - locate character in string strcasecmp - compare two strings ignoring case compare two strings ignoring case string - string operations strncasecmp - compare two strings ignoring case sys/ipc.h ftok - convert a pathname and a project identifier to a Syste... sys/mman.h madvise - give advice about use of memory memfd_create - create an anonymous file mincore - determine whether pages are resident in memory mlock - lock and unlock memory mlock2 - lock and unlock memory mlockall - lock and unlock memory mmap - map or unmap files or devices into memory mmap64 - map or unmap files or devices into memory mprotect - set protection on a region of memory mremap - remap a virtual memory address msync - synchronize a file with a memory map munlock - lock and unlock memory munlockall - lock and unlock memory munmap - map or unmap files or devices into memory pkey_alloc - allocate or free a protection key pkey_free - allocate or free a protection key pkey_mprotect - set protection on a region of memory posix_madvise - give advice about patterns of memory usage process_madvise - give advice about use of memory to a process remap_file_pages - create a nonlinear file mapping shm_open - create/open or unlink POSIX shared memory objects shm_unlink - create/open or unlink POSIX shared memory objects sys/msg.h msgctl - System V message control operations msgget - get a System V message queue identifier msgop - System V message queue operations msgrcv - System V message queue operations msgsnd - System V message queue operations sys/resource.h getpriority - get/set program scheduling priority getrlimit - get/set resource limits getrusage - get resource usage prlimit - get/set resource limits prlimit64 - get/set resource limits setpriority - get/set program scheduling priority setrlimit - get/set resource limits ugetrlimit - get/set resource limits vlimit - get/set resource limits vtimes - get resource usage sys/select.h _newselect - synchronous I/O multiplexing FD_CLR - synchronous I/O multiplexing FD_ISSET - synchronous I/O multiplexing FD_SET - synchronous I/O multiplexing FD_ZERO - synchronous I/O multiplexing pselect - synchronous I/O multiplexing pselect6 - synchronous I/O multiplexing select - synchronous I/O multiplexing sys/sem.h semctl - System V semaphore control operations semget - get a System V semaphore set identifier semop - System V semaphore operations semtimedop - System V semaphore operations sys/shm.h shmat - System V shared memory operations shmctl - System V shared memory control shmdt - System V shared memory operations shmget - allocates a System V shared memory segment shmop - System V shared memory operations sys/socket.h accept - accept a connection on a socket accept4 - accept a connection on a socket address_families - socket address families (domains) bind - bind a name to a socket cmsg - access ancillary data CMSG_ALIGN - access ancillary data CMSG_DATA - access ancillary data CMSG_FIRSTHDR - access ancillary data CMSG_LEN - access ancillary data CMSG_NXTHDR - access ancillary data CMSG_SPACE - access ancillary data connect - initiate a connection on a socket ddp - Linux AppleTalk protocol implementation getnameinfo - address-to-name translation in protocol-independent ma... getpeername - get name of connected peer socket getsockname - get socket name getsockopt - get and set options on sockets inet - Internet address manipulation routines inet_addr - Internet address manipulation routines inet_aton - Internet address manipulation routines inet_lnaof - Internet address manipulation routines inet_makeaddr - Internet address manipulation routines inet_netof - Internet address manipulation routines inet_network - Internet address manipulation routines inet_ntoa - Internet address manipulation routines ip - Linux IPv4 protocol implementation ipv6 - Linux IPv6 protocol implementation listen - listen for connections on a socket packet - packet interface on device level raw - Linux IPv4 raw sockets recv - receive a message from a socket recvfrom - receive a message from a socket recvmmsg - receive multiple messages on a socket recvmsg - receive a message from a socket send - send a message on a socket sendmmsg - send multiple messages on a socket sendmsg - send a message on a socket sendto - send a message on a socket setsockopt - get and set options on sockets shutdown - shut down part of a full-duplex connection sock_diag - obtaining information about sockets sockatmark - determine whether socket is at out-of-band mark socket - create an endpoint for communication socket - Linux socket interface socketpair - create a pair of connected sockets tcp - TCP protocol udp - User Datagram Protocol for IPv4 udplite - Lightweight User Datagram Protocol unix - sockets for local interprocess communication vsock - Linux VSOCK address family x25 - ITU-T X.25 / ISO/IEC 8208 protocol interface sys/stat.h chmod - change permissions of a file fchmod - change permissions of a file fchmodat - change permissions of a file fstat - get file status fstat64 - get file status fstatat - get file status fstatat64 - get file status futimens - change file timestamps with nanosecond precision isfdtype - test file type of a file descriptor lstat - get file status lstat64 - get file status mkdir - create a directory mkdirat - create a directory mknod - create a special or ordinary file mknodat - create a special or ordinary file newfstatat - get file status oldfstat - get file status oldlstat - get file status oldstat - get file status stat - get file status stat64 - get file status statx - get file status (extended) umask - set file mode creation mask utimensat - change file timestamps with nanosecond precision sys/statvfs.h fstatvfs - get filesystem statistics statvfs - get filesystem statistics sys/time.h adjtime - correct the time to synchronize the system clock futimes - change file timestamps futimesat - change timestamps of a file relative to a directory fi... getitimer - get or set value of an interval timer gettimeofday - get / set time lutimes - change file timestamps setitimer - get or set value of an interval timer settimeofday - get / set time timeradd - timeval operations timerclear - timeval operations timercmp - timeval operations timerisset - timeval operations timersub - timeval operations TIMESPEC_TO_TIMEVAL - convert between time structures TIMEVAL_TO_TIMESPEC - convert between time structures sys/times.h times - get process times sys/types.h bindresvport - bind a socket to a privileged IP port closedir - close a directory db - database access methods dbopen - database access methods dirfd - get directory stream file descriptor endgrent - get group file entry endpwent - get password file entry fdopendir - open a directory freeaddrinfo - network address and service translation freehostent - get network hostnames and addresses freeifaddrs - get interface addresses fts - traverse a file hierarchy fts_children - traverse a file hierarchy fts_close - traverse a file hierarchy fts_open - traverse a file hierarchy fts_read - traverse a file hierarchy fts_set - traverse a file hierarchy gai_strerror - network address and service translation getaddrinfo - network address and service translation getgrent - get group file entry getgrgid - get group file entry getgrgid_r - get group file entry getgrnam - get group file entry getgrnam_r - get group file entry getifaddrs - get interface addresses getipnodebyaddr - get network hostnames and addresses getipnodebyname - get network hostnames and addresses getpw - reconstruct password line entry getpwent - get password file entry getpwnam - get password file entry getpwnam_r - get password file entry getpwuid - get password file entry getpwuid_r - get password file entry initgroups - initialize the supplementary group access list lseek64 - reposition 64-bit read/write file offset mkfifo - make a FIFO special file (a named pipe) mkfifoat - make a FIFO special file (a named pipe) opendir - open a directory re_comp - BSD regex functions re_exec - BSD regex functions rewinddir - reset directory stream setgrent - get group file entry setpwent - get password file entry ustat - get filesystem statistics sys/uio.h preadv - read or write data into multiple buffers preadv2 - read or write data into multiple buffers process_vm_readv - transfer data between process address spaces process_vm_writev - transfer data between process address spaces pwritev - read or write data into multiple buffers pwritev2 - read or write data into multiple buffers readv - read or write data into multiple buffers writev - read or write data into multiple buffers sys/utsname.h oldolduname - get name and information about current kernel olduname - get name and information about current kernel uname - get name and information about current kernel sys/wait.h wait - wait for process to change state wait3 - wait for process to change state, BSD style wait4 - wait for process to change state, BSD style waitid - wait for process to change state waitpid - wait for process to change state syslog.h closelog - send messages to the system logger openlog - send messages to the system logger setlogmask - set log priority mask syslog - send messages to the system logger vsyslog - send messages to the system logger termios.h cfgetispeed - get and set terminal attributes, line control, get and... cfgetospeed - get and set terminal attributes, line control, get and... cfmakeraw - get and set terminal attributes, line control, get and... cfsetispeed - get and set terminal attributes, line control, get and... cfsetospeed - get and set terminal attributes, line control, get and... cfsetspeed - get and set terminal attributes, line control, get and... tcdrain - get and set terminal attributes, line control, get and... tcflow - get and set terminal attributes, line control, get and... tcflush - get and set terminal attributes, line control, get and... tcgetattr - get and set terminal attributes, line control, get and... tcgetsid - get session ID tcsendbreak - get and set terminal attributes, line control, get and... tcsetattr - get and set terminal attributes, line control, get and... termios - get and set terminal attributes, line control, get and... time.h asctime - transform date and time to broken-down time or ASCII asctime_r - transform date and time to broken-down time or ASCII clock - determine processor time clock_getcpuclockid - obtain ID of a process CPU-time clock clock_getres - clock and time functions clock_gettime - clock and time functions clock_nanosleep - high-resolution sleep with specifiable clock clock_settime - clock and time functions ctime - transform date and time to broken-down time or ASCII ctime_r - transform date and time to broken-down time or ASCII daylight - initialize time conversion information difftime - calculate time difference dysize - get number of days for a given year getdate - convert a date-plus-time string to broken-down time getdate_err - convert a date-plus-time string to broken-down time getdate_r - convert a date-plus-time string to broken-down time gmtime - transform date and time to broken-down time or ASCII gmtime_r - transform date and time to broken-down time or ASCII localtime - transform date and time to broken-down time or ASCII localtime_r - transform date and time to broken-down time or ASCII mktime - transform date and time to broken-down time or ASCII nanosleep - high-resolution sleep stime - set time strftime - format date and time strftime_l - format date and time strptime - convert a string representation of time to a time tm s... time - get time in seconds get time in seconds timegm - inverses of gmtime and localtime timelocal - inverses of gmtime and localtime timer_create - create a POSIX per-process timer timer_delete - delete a POSIX per-process timer timer_getoverrun - get overrun count for a POSIX per-process timer timer_gettime - arm/disarm and fetch state of POSIX per-process timer timer_settime - arm/disarm and fetch state of POSIX per-process timer timezone - initialize time conversion information tzname - initialize time conversion information tzset - initialize time conversion information ulimit.h ulimit - get and set user limits unistd.h _Exit - terminate the calling process _exit - terminate the calling process _llseek - reposition read/write file offset _sysctl - read/write system parameters access - check user's permissions for a file acct - switch process accounting on or off alarm - set an alarm clock for delivery of a signal arch_prctl - set architecture-specific thread state brk - change data segment size capget - set/get capabilities of thread(s) capset - set/get capabilities of thread(s) chdir - change working directory chown - change ownership of a file chown32 - change ownership of a file chroot - change root directory close - close a file descriptor close_range - close all file descriptors in a given range confstr - get configuration dependent string variables copy_file_range - Copy a range of data from one file to another cuserid - get username daemon - run in the background delete_module - unload a kernel module dup - duplicate a file descriptor dup2 - duplicate a file descriptor dup3 - duplicate a file descriptor eaccess - check effective user's permissions for a file encrypt - encrypt 64-bit messages encrypt_r - encrypt 64-bit messages endusershell - get permitted user shells euidaccess - check effective user's permissions for a file exec - execute a file execl - execute a file execle - execute a file execlp - execute a file execv - execute a file execve - execute program execveat - execute program relative to a directory file descriptor execvp - execute a file execvpe - execute a file exit - terminate the calling process exit_group - exit all threads in a process faccessat - check user's permissions for a file faccessat2 - check user's permissions for a file fchdir - change working directory fchown - change ownership of a file fchown32 - change ownership of a file fchownat - change ownership of a file fdatasync - synchronize a file's in-core state with storage device fexecve - execute program specified via file descriptor finit_module - load a kernel module fork - create a child process fpathconf - get configuration values for files fsync - synchronize a file's in-core state with storage device ftruncate - truncate a file to a specified length ftruncate64 - truncate a file to a specified length futex - fast user-space locking get_current_dir_name - get current working directory get_robust_list - get/set list of robust futexes get_thread_area - manipulate thread-local storage information getcwd - get current working directory getcwd - get current working directory getdents - get directory entries getdents64 - get directory entries getdomainname - get/set NIS domain name getdtablesize - get file descriptor table size getegid - get group identity getegid32 - get group identity getentropy - fill a buffer with random bytes geteuid - get user identity geteuid32 - get user identity getgid - get group identity getgid32 - get group identity getgroups - get/set list of supplementary group IDs getgroups32 - get/set list of supplementary group IDs gethostid - get or set the unique identifier of the current host gethostname - get/set hostname getlogin - get username getlogin_r - get username getopt - Parse command-line options getopt_long - Parse command-line options getopt_long_only - Parse command-line options getpagesize - get memory page size getpass - get a password getpgid - set/get process group getpgrp - set/get process group getpid - get process identification getppid - get process identification getresgid - get real, effective, and saved user/group IDs getresgid32 - get real, effective, and saved user/group IDs getresuid - get real, effective, and saved user/group IDs getresuid32 - get real, effective, and saved user/group IDs getsid - get session ID gettid - get thread identification getuid - get user identity getuid32 - get user identity getusershell - get permitted user shells getwd - get current working directory group_member - test whether a process is in a group idle - make process 0 idle init_module - load a kernel module io_cancel - cancel an outstanding asynchronous I/O operation io_destroy - destroy an asynchronous I/O context io_getevents - read asynchronous I/O events from the completion queue ioprio_get - get/set I/O scheduling class and priority ioprio_set - get/set I/O scheduling class and priority ipc - System V IPC system calls isatty - test whether a file descriptor refers to a terminal kcmp - compare two processes to determine if they share a ker... kexec_file_load - load a new kernel for later execution kexec_load - load a new kernel for later execution keyctl - manipulate the kernel's key management facility klogctl - read and/or clear kernel message ring buffer; set cons... lchown - change ownership of a file lchown32 - change ownership of a file link - make a new name for a file linkat - make a new name for a file llseek - reposition read/write file offset lockf - apply, test or remove a POSIX lock on an open file lookup_dcookie - return a directory entry's path lseek - reposition read/write file offset membarrier - issue memory barriers on a set of threads memfd_secret - create an anonymous RAM-based file to access secret me... mmap2 - map files or devices into memory modify_ldt - get or set a per-process LDT entry mount_setattr - change properties of a mount or mount tree mq_getsetattr - get/set message queue attributes nice - change process priority openat2 - open and possibly create a file (extended) optarg - Parse command-line options opterr - Parse command-line options optind - Parse command-line options optopt - Parse command-line options pathconf - get configuration values for files pause - wait for signal perf_event_open - set up performance monitoring pidfd_getfd - obtain a duplicate of another process's file descriptor pidfd_open - obtain a file descriptor that refers to a process pidfd_send_signal - send a signal to a process specified by a file descri... pipe - create pipe pipe2 - create pipe pivot_root - change the root mount pread - read from or write to a file descriptor at a given offset pread64 - read from or write to a file descriptor at a given offset profil - execution time profile pwrite - read from or write to a file descriptor at a given offset pwrite64 - read from or write to a file descriptor at a given offset read - read from a file descriptor readdir - read directory entry readlink - read value of a symbolic link readlinkat - read value of a symbolic link reboot - reboot or enable/disable Ctrl-Alt-Del rmdir - delete a directory rt_sigqueueinfo - queue a signal and data rt_tgsigqueueinfo - queue a signal and data s390_guarded_storage - operations with z/Architecture guarded storage fac... s390_pci_mmio_read - transfer data to/from PCI MMIO memory page s390_pci_mmio_write - transfer data to/from PCI MMIO memory page s390_runtime_instr - enable/disable s390 CPU run-time instrumentation s390_sthyi - emulate STHYI instruction sbrk - change data segment size sched_getattr - set and get scheduling policy and attributes sched_setattr - set and get scheduling policy and attributes seccomp - operate on Secure Computing state of the process set_robust_list - get/set list of robust futexes set_thread_area - manipulate thread-local storage information set_tid_address - set pointer to thread ID setdomainname - get/set NIS domain name setegid - set effective user or group ID seteuid - set effective user or group ID setgid - set group identity setgid32 - set group identity setgroups - get/set list of supplementary group IDs setgroups32 - get/set list of supplementary group IDs sethostid - get or set the unique identifier of the current host sethostname - get/set hostname setkey - encrypt 64-bit messages setkey_r - encrypt 64-bit messages setpgid - set/get process group setpgrp - set/get process group setregid - set real and/or effective user or group ID setregid32 - set real and/or effective user or group ID setresgid - set real, effective, and saved user or group ID setresgid32 - set real, effective, and saved user or group ID setresuid - set real, effective, and saved user or group ID setresuid32 - set real, effective, and saved user or group ID setreuid - set real and/or effective user or group ID setreuid32 - set real and/or effective user or group ID setsid - creates a session and sets the process group ID setuid - set user identity setuid32 - set user identity setup - setup devices and filesystems, mount root filesystem setusershell - get permitted user shells sgetmask - manipulation of signal mask (obsolete) sleep - sleep for a specified number of seconds socketcall - socket system calls spu_create - create a new spu context spu_run - execute an SPU context ssetmask - manipulation of signal mask (obsolete) subpage_prot - define a subpage protection for an address range swab - swap adjacent bytes symlink - make a new name for a file symlinkat - make a new name for a file sync - commit filesystem caches to disk syncfs - commit filesystem caches to disk syscall - indirect system call sysconf - get configuration information at run time sysctl - read/write system parameters syslog - read and/or clear kernel message ring buffer; set cons... tcgetpgrp - get and set terminal foreground process group tcsetpgrp - get and set terminal foreground process group tgkill - send a signal to a thread tkill - send a signal to a thread truncate - truncate a file to a specified length truncate64 - truncate a file to a specified length ttyname - return name of a terminal ttyname_r - return name of a terminal ualarm - schedule signal after given number of microseconds unlink - delete a name and possibly the file it refers to unlinkat - delete a name and possibly the file it refers to uselib - load shared library userfaultfd - create a file descriptor for handling page faults in u... usleep - suspend execution for microsecond intervals vfork - create a child process and block parent vhangup - virtually hangup the current terminal write - write to a file descriptor utime.h utime - change file last access and modification times utimes - change file last access and modification times utmpx.h getutmp - copy utmp structure to utmpx, and vice versa getutmpx - copy utmp structure to utmpx, and vice versa wchar.h btowc - convert single byte to wide character fgetws - read a wide-character string from a FILE stream fputws - write a wide-character string to a FILE stream fwide - set and determine the orientation of a FILE stream getwchar - read a wide character from standard input mbrlen - determine number of bytes in next multibyte character mbrtowc - convert a multibyte sequence to a wide character mbsinit - test for initial shift state mbsnrtowcs - convert a multibyte string to a wide-character string mbsrtowcs - convert a multibyte string to a wide-character string ... putwchar - write a wide character to standard output ungetwc - push back a wide character onto a FILE stream wcpcpy - copy a wide-character string, returning a pointer to i... wcpncpy - copy a fixed-size string of wide characters, returning... wcrtomb - convert a wide character to a multibyte sequence wcscasecmp - compare two wide-character strings, ignoring case wcscat - concatenate two wide-character strings wcschr - search a wide character in a wide-character string wcscmp - compare two wide-character strings wcscpy - copy a wide-character string wcscspn - search a wide-character string for any of a set of wid... wcsdup - duplicate a wide-character string wcslen - determine the length of a wide-character string wcsncasecmp - compare two fixed-size wide-character strings, ignorin... wcsncat - concatenate two wide-character strings wcsncmp - compare two fixed-size wide-character strings wcsncpy - copy a fixed-size string of wide characters wcsnlen - determine the length of a fixed-size wide-character st... wcsnrtombs - convert a wide-character string to a multibyte string wcspbrk - search a wide-character string for any of a set of wid... wcsrchr - search a wide character in a wide-character string wcsrtombs - convert a wide-character string to a multibyte string wcsspn - get length of a prefix wide-character substring wcsstr - locate a substring in a wide-character string wcstok - split wide-character string into tokens wcswidth - determine columns needed for a fixed-size wide-charact... wctob - try to represent a wide character as a single byte wcwidth - determine columns needed for a wide character wmemchr - search a wide character in a wide-character array wmemcmp - compare two arrays of wide-characters wmemcpy - copy an array of wide-characters wmemmove - copy an array of wide-characters wmemset - fill an array of wide-characters with a constant wide ... wctype.h iswalnum - test for alphanumeric wide character iswalpha - test for alphabetic wide character iswblank - test for whitespace wide character iswcntrl - test for control wide character iswctype - wide-character classification iswdigit - test for decimal digit wide character iswgraph - test for graphic wide character iswlower - test for lowercase wide character iswprint - test for printing wide character iswpunct - test for punctuation or symbolic wide character iswspace - test for whitespace wide character iswupper - test for uppercase wide character iswxdigit - test for hexadecimal digit wide character towctrans - wide-character transliteration towlower - convert a wide character to lowercase towlower_l - convert a wide character to lowercase towupper - convert a wide character to uppercase towupper_l - convert a wide character to uppercase wctrans - wide-character translation mapping wctype - wide-character classification wordexp.h wordexp - perform word expansion like a posix-shell wordfree - perform word expansion like a posix-shell
Markdown	[CS50 Manual Pages](https://manual.cs50.io/) Manual pages for the C standard library, the C POSIX library, and the CS50 Library for [those less comfortable](). # [aio.h](https://manual.cs50.io/#aio.h) - [aio\_cancel](https://manual.cs50.io/3/aio_cancel) - cancel an outstanding asynchronous I/O request - [aio\_error](https://manual.cs50.io/3/aio_error) - get error status of asynchronous I/O operation - [aio\_fsync](https://manual.cs50.io/3/aio_fsync) - asynchronous file synchronization - [aio\_init](https://manual.cs50.io/3/aio_init) - asynchronous I/O initialization - [aio\_read](https://manual.cs50.io/3/aio_read) - asynchronous read - [aio\_return](https://manual.cs50.io/3/aio_return) - get return status of asynchronous I/O operation - [aio\_suspend](https://manual.cs50.io/3/aio_suspend) - wait for asynchronous I/O operation or timeout - [aio\_write](https://manual.cs50.io/3/aio_write) - asynchronous write - [lio\_listio](https://manual.cs50.io/3/lio_listio) - initiate a list of I/O requests # [arpa/inet.h](https://manual.cs50.io/#arpa/inet.h) - [byteorder](https://manual.cs50.io/3/byteorder) - convert values between host and network byte order - [htonl](https://manual.cs50.io/3/htonl) - convert values between host and network byte order - [htons](https://manual.cs50.io/3/htons) - convert values between host and network byte order - [inet\_net\_ntop](https://manual.cs50.io/3/inet_net_ntop) - Internet network number conversion - [inet\_net\_pton](https://manual.cs50.io/3/inet_net_pton) - Internet network number conversion - [inet\_ntop](https://manual.cs50.io/3/inet_ntop) - convert IPv4 and IPv6 addresses from binary to text form - [inet\_pton](https://manual.cs50.io/3/inet_pton) - convert IPv4 and IPv6 addresses from text to binary form - [ntohl](https://manual.cs50.io/3/ntohl) - convert values between host and network byte order - [ntohs](https://manual.cs50.io/3/ntohs) - convert values between host and network byte order # [assert.h](https://manual.cs50.io/#assert.h) - [\_Static\_assert](https://manual.cs50.io/3/_Static_assert) - fail compilation if assertion is false - [assert](https://manual.cs50.io/3/assert) - abort the program if assertion is false - [assert\_perror](https://manual.cs50.io/3/assert_perror) - test errnum and abort - [static\_assert](https://manual.cs50.io/3/static_assert) - fail compilation if assertion is false # [complex.h](https://manual.cs50.io/#complex.h) - [cabs](https://manual.cs50.io/3/cabs) - absolute value of a complex number - [cabsf](https://manual.cs50.io/3/cabsf) - absolute value of a complex number - [cabsl](https://manual.cs50.io/3/cabsl) - absolute value of a complex number - [cacos](https://manual.cs50.io/3/cacos) - complex arc cosine - [cacosf](https://manual.cs50.io/3/cacosf) - complex arc cosine - [cacosh](https://manual.cs50.io/3/cacosh) - complex arc hyperbolic cosine - [cacoshf](https://manual.cs50.io/3/cacoshf) - complex arc hyperbolic cosine - [cacoshl](https://manual.cs50.io/3/cacoshl) - complex arc hyperbolic cosine - [cacosl](https://manual.cs50.io/3/cacosl) - complex arc cosine - [carg](https://manual.cs50.io/3/carg) - calculate the complex argument - [cargf](https://manual.cs50.io/3/cargf) - calculate the complex argument - [cargl](https://manual.cs50.io/3/cargl) - calculate the complex argument - [casin](https://manual.cs50.io/3/casin) - complex arc sine - [casinf](https://manual.cs50.io/3/casinf) - complex arc sine - [casinh](https://manual.cs50.io/3/casinh) - complex arc sine hyperbolic - [casinhf](https://manual.cs50.io/3/casinhf) - complex arc sine hyperbolic - [casinhl](https://manual.cs50.io/3/casinhl) - complex arc sine hyperbolic - [casinl](https://manual.cs50.io/3/casinl) - complex arc sine - [catan](https://manual.cs50.io/3/catan) - complex arc tangents - [catanf](https://manual.cs50.io/3/catanf) - complex arc tangents - [catanh](https://manual.cs50.io/3/catanh) - complex arc tangents hyperbolic - [catanhf](https://manual.cs50.io/3/catanhf) - complex arc tangents hyperbolic - [catanhl](https://manual.cs50.io/3/catanhl) - complex arc tangents hyperbolic - [catanl](https://manual.cs50.io/3/catanl) - complex arc tangents - [ccos](https://manual.cs50.io/3/ccos) - complex cosine function - [ccosf](https://manual.cs50.io/3/ccosf) - complex cosine function - [ccosh](https://manual.cs50.io/3/ccosh) - complex hyperbolic cosine - [ccoshf](https://manual.cs50.io/3/ccoshf) - complex hyperbolic cosine - [ccoshl](https://manual.cs50.io/3/ccoshl) - complex hyperbolic cosine - [ccosl](https://manual.cs50.io/3/ccosl) - complex cosine function - [cexp](https://manual.cs50.io/3/cexp) - complex exponential function - [cexp2](https://manual.cs50.io/3/cexp2) - base-2 exponent of a complex number - [cexp2f](https://manual.cs50.io/3/cexp2f) - base-2 exponent of a complex number - [cexp2l](https://manual.cs50.io/3/cexp2l) - base-2 exponent of a complex number - [cexpf](https://manual.cs50.io/3/cexpf) - complex exponential function - [cexpl](https://manual.cs50.io/3/cexpl) - complex exponential function - [cimag](https://manual.cs50.io/3/cimag) - get imaginary part of a complex number - [cimagf](https://manual.cs50.io/3/cimagf) - get imaginary part of a complex number - [cimagl](https://manual.cs50.io/3/cimagl) - get imaginary part of a complex number - [clog](https://manual.cs50.io/3/clog) - natural logarithm of a complex number - [clog10](https://manual.cs50.io/3/clog10) - base-10 logarithm of a complex number - [clog10f](https://manual.cs50.io/3/clog10f) - base-10 logarithm of a complex number - [clog10l](https://manual.cs50.io/3/clog10l) - base-10 logarithm of a complex number - [clog2](https://manual.cs50.io/3/clog2) - base-2 logarithm of a complex number - [clog2f](https://manual.cs50.io/3/clog2f) - base-2 logarithm of a complex number - [clog2l](https://manual.cs50.io/3/clog2l) - base-2 logarithm of a complex number - [clogf](https://manual.cs50.io/3/clogf) - natural logarithm of a complex number - [clogl](https://manual.cs50.io/3/clogl) - natural logarithm of a complex number - [complex](https://manual.cs50.io/7/complex) - basics of complex mathematics - [conj](https://manual.cs50.io/3/conj) - calculate the complex conjugate - [conjf](https://manual.cs50.io/3/conjf) - calculate the complex conjugate - [conjl](https://manual.cs50.io/3/conjl) - calculate the complex conjugate - [cpow](https://manual.cs50.io/3/cpow) - complex power function - [cpowf](https://manual.cs50.io/3/cpowf) - complex power function - [cpowl](https://manual.cs50.io/3/cpowl) - complex power function - [cproj](https://manual.cs50.io/3/cproj) - project into Riemann Sphere - [cprojf](https://manual.cs50.io/3/cprojf) - project into Riemann Sphere - [cprojl](https://manual.cs50.io/3/cprojl) - project into Riemann Sphere - [creal](https://manual.cs50.io/3/creal) - get real part of a complex number - [crealf](https://manual.cs50.io/3/crealf) - get real part of a complex number - [creall](https://manual.cs50.io/3/creall) - get real part of a complex number - [csin](https://manual.cs50.io/3/csin) - complex sine function - [csinf](https://manual.cs50.io/3/csinf) - complex sine function - [csinh](https://manual.cs50.io/3/csinh) - complex hyperbolic sine - [csinhf](https://manual.cs50.io/3/csinhf) - complex hyperbolic sine - [csinhl](https://manual.cs50.io/3/csinhl) - complex hyperbolic sine - [csinl](https://manual.cs50.io/3/csinl) - complex sine function - [csqrt](https://manual.cs50.io/3/csqrt) - complex square root - [csqrtf](https://manual.cs50.io/3/csqrtf) - complex square root - [csqrtl](https://manual.cs50.io/3/csqrtl) - complex square root - [ctan](https://manual.cs50.io/3/ctan) - complex tangent function - [ctanf](https://manual.cs50.io/3/ctanf) - complex tangent function - [ctanh](https://manual.cs50.io/3/ctanh) - complex hyperbolic tangent - [ctanhf](https://manual.cs50.io/3/ctanhf) - complex hyperbolic tangent - [ctanhl](https://manual.cs50.io/3/ctanhl) - complex hyperbolic tangent - [ctanl](https://manual.cs50.io/3/ctanl) - complex tangent function # [cs50.h](https://manual.cs50.io/#cs50.h) - [get\_char](https://manual.cs50.io/3/get_char) - prompts user for a line of text from stdin and returns... prompt a user for a `char` - [get\_double](https://manual.cs50.io/3/get_double) - prompts user for a line of text from stdin and returns... prompt a user for a `double` - [get\_float](https://manual.cs50.io/3/get_float) - prompts user for a line of text from stdin and returns... prompt a user for a `float` - [get\_int](https://manual.cs50.io/3/get_int) - prompts user for a line of text from stdin and returns... prompt a user for an `int` - [get\_long](https://manual.cs50.io/3/get_long) - prompts user for a line of text from stdin and returns... prompt a user for an `long` - [get\_long\_long](https://manual.cs50.io/3/get_long_long) - prompts user for a line of text from stdin and returns... - [get\_string](https://manual.cs50.io/3/get_string) - prompts user for a line of text from stdin and returns... prompt a user for a `string` # [ctype.h](https://manual.cs50.io/#ctype.h) - [isalnum](https://manual.cs50.io/3/isalnum) - character classification functions check whether a character is alphanumeric - [isalnum\_l](https://manual.cs50.io/3/isalnum_l) - character classification functions - [isalpha](https://manual.cs50.io/3/isalpha) - character classification functions check whether a character is alphabetical - [isalpha\_l](https://manual.cs50.io/3/isalpha_l) - character classification functions - [isascii](https://manual.cs50.io/3/isascii) - character classification functions - [isascii\_l](https://manual.cs50.io/3/isascii_l) - character classification functions - [isblank](https://manual.cs50.io/3/isblank) - character classification functions check whether a character is blank (i.e., a space or tab) - [isblank\_l](https://manual.cs50.io/3/isblank_l) - character classification functions - [iscntrl](https://manual.cs50.io/3/iscntrl) - character classification functions - [iscntrl\_l](https://manual.cs50.io/3/iscntrl_l) - character classification functions - [isdigit](https://manual.cs50.io/3/isdigit) - character classification functions check whether a character is a digit - [isdigit\_l](https://manual.cs50.io/3/isdigit_l) - character classification functions - [isgraph](https://manual.cs50.io/3/isgraph) - character classification functions - [isgraph\_l](https://manual.cs50.io/3/isgraph_l) - character classification functions - [islower](https://manual.cs50.io/3/islower) - character classification functions check whether a character is lowercase - [islower\_l](https://manual.cs50.io/3/islower_l) - character classification functions - [isprint](https://manual.cs50.io/3/isprint) - character classification functions - [isprint\_l](https://manual.cs50.io/3/isprint_l) - character classification functions - [ispunct](https://manual.cs50.io/3/ispunct) - character classification functions check whether a character is punctuation - [ispunct\_l](https://manual.cs50.io/3/ispunct_l) - character classification functions - [isspace](https://manual.cs50.io/3/isspace) - character classification functions check whether a character is whitespace (e.g., a newline, space, or tab) - [isspace\_l](https://manual.cs50.io/3/isspace_l) - character classification functions - [isupper](https://manual.cs50.io/3/isupper) - character classification functions check whether a character is uppercase - [isupper\_l](https://manual.cs50.io/3/isupper_l) - character classification functions - [isxdigit](https://manual.cs50.io/3/isxdigit) - character classification functions - [isxdigit\_l](https://manual.cs50.io/3/isxdigit_l) - character classification functions - [toascii](https://manual.cs50.io/3/toascii) - convert character to ASCII - [tolower](https://manual.cs50.io/3/tolower) - convert uppercase or lowercase convert a `char` to lowercase - [tolower\_l](https://manual.cs50.io/3/tolower_l) - convert uppercase or lowercase - [toupper](https://manual.cs50.io/3/toupper) - convert uppercase or lowercase convert a `char` to uppercase - [toupper\_l](https://manual.cs50.io/3/toupper_l) - convert uppercase or lowercase # [dirent.h](https://manual.cs50.io/#dirent.h) - [alphasort](https://manual.cs50.io/3/alphasort) - scan a directory for matching entries - [getdirentries](https://manual.cs50.io/3/getdirentries) - get directory entries in a filesystem-independent format - [readdir](https://manual.cs50.io/3/readdir) - read a directory - [readdir\_r](https://manual.cs50.io/3/readdir_r) - read a directory - [scandir](https://manual.cs50.io/3/scandir) - scan a directory for matching entries - [scandirat](https://manual.cs50.io/3/scandirat) - scan a directory for matching entries - [seekdir](https://manual.cs50.io/3/seekdir) - set the position of the next readdir() call in the dir... - [telldir](https://manual.cs50.io/3/telldir) - return current location in directory stream - [versionsort](https://manual.cs50.io/3/versionsort) - scan a directory for matching entries # [dlfcn.h](https://manual.cs50.io/#dlfcn.h) - [dladdr](https://manual.cs50.io/3/dladdr) - translate address to symbolic information - [dladdr1](https://manual.cs50.io/3/dladdr1) - translate address to symbolic information - [dlclose](https://manual.cs50.io/3/dlclose) - open and close a shared object - [dlerror](https://manual.cs50.io/3/dlerror) - obtain error diagnostic for functions in the dlopen API - [dlmopen](https://manual.cs50.io/3/dlmopen) - open and close a shared object - [dlopen](https://manual.cs50.io/3/dlopen) - open and close a shared object - [dlsym](https://manual.cs50.io/3/dlsym) - obtain address of a symbol in a shared object or execu... - [dlvsym](https://manual.cs50.io/3/dlvsym) - obtain address of a symbol in a shared object or execu... # [errno.h](https://manual.cs50.io/#errno.h) - [errno](https://manual.cs50.io/3/errno) - number of last error - [program\_invocation\_name](https://manual.cs50.io/3/program_invocation_name) - obtain name used to invoke calling program - [program\_invocation\_short\_name](https://manual.cs50.io/3/program_invocation_short_name) - obtain name used to invoke calling program # [fcntl.h](https://manual.cs50.io/#fcntl.h) - [arm\_fadvise](https://manual.cs50.io/2/arm_fadvise) - predeclare an access pattern for file data - [arm\_fadvise64\_64](https://manual.cs50.io/2/arm_fadvise64_64) - predeclare an access pattern for file data - [arm\_sync\_file\_range](https://manual.cs50.io/2/arm_sync_file_range) - sync a file segment with disk - [creat](https://manual.cs50.io/2/creat) - open and possibly create a file - [fadvise64](https://manual.cs50.io/2/fadvise64) - predeclare an access pattern for file data - [fadvise64\_64](https://manual.cs50.io/2/fadvise64_64) - predeclare an access pattern for file data - [fallocate](https://manual.cs50.io/2/fallocate) - manipulate file space - [fcntl](https://manual.cs50.io/2/fcntl) - manipulate file descriptor - [fcntl64](https://manual.cs50.io/2/fcntl64) - manipulate file descriptor - [name\_to\_handle\_at](https://manual.cs50.io/2/name_to_handle_at) - obtain handle for a pathname and open file via a handle - [open](https://manual.cs50.io/2/open) - open and possibly create a file - [open\_by\_handle\_at](https://manual.cs50.io/2/open_by_handle_at) - obtain handle for a pathname and open file via a handle - [openat](https://manual.cs50.io/2/openat) - open and possibly create a file - [posix\_fadvise](https://manual.cs50.io/2/posix_fadvise) - predeclare an access pattern for file data - [posix\_fallocate](https://manual.cs50.io/3/posix_fallocate) - allocate file space - [readahead](https://manual.cs50.io/2/readahead) - initiate file readahead into page cache - [splice](https://manual.cs50.io/2/splice) - splice data to/from a pipe - [sync\_file\_range](https://manual.cs50.io/2/sync_file_range) - sync a file segment with disk - [sync\_file\_range2](https://manual.cs50.io/2/sync_file_range2) - sync a file segment with disk - [tee](https://manual.cs50.io/2/tee) - duplicating pipe content - [vmsplice](https://manual.cs50.io/2/vmsplice) - splice user pages to/from a pipe # [fenv.h](https://manual.cs50.io/#fenv.h) - [feclearexcept](https://manual.cs50.io/3/feclearexcept) - floating-point rounding and exception handling - [fedisableexcept](https://manual.cs50.io/3/fedisableexcept) - floating-point rounding and exception handling - [feenableexcept](https://manual.cs50.io/3/feenableexcept) - floating-point rounding and exception handling - [fegetenv](https://manual.cs50.io/3/fegetenv) - floating-point rounding and exception handling - [fegetexcept](https://manual.cs50.io/3/fegetexcept) - floating-point rounding and exception handling - [fegetexceptflag](https://manual.cs50.io/3/fegetexceptflag) - floating-point rounding and exception handling - [fegetround](https://manual.cs50.io/3/fegetround) - floating-point rounding and exception handling - [feholdexcept](https://manual.cs50.io/3/feholdexcept) - floating-point rounding and exception handling - [fenv](https://manual.cs50.io/3/fenv) - floating-point rounding and exception handling - [feraiseexcept](https://manual.cs50.io/3/feraiseexcept) - floating-point rounding and exception handling - [fesetenv](https://manual.cs50.io/3/fesetenv) - floating-point rounding and exception handling - [fesetexceptflag](https://manual.cs50.io/3/fesetexceptflag) - floating-point rounding and exception handling - [fesetround](https://manual.cs50.io/3/fesetround) - floating-point rounding and exception handling - [fetestexcept](https://manual.cs50.io/3/fetestexcept) - floating-point rounding and exception handling - [feupdateenv](https://manual.cs50.io/3/feupdateenv) - floating-point rounding and exception handling # [fmtmsg.h](https://manual.cs50.io/#fmtmsg.h) - [addseverity](https://manual.cs50.io/3/addseverity) - introduce new severity classes - [fmtmsg](https://manual.cs50.io/3/fmtmsg) - print formatted error messages # [fnmatch.h](https://manual.cs50.io/#fnmatch.h) - [fnmatch](https://manual.cs50.io/3/fnmatch) - match filename or pathname # [ftw.h](https://manual.cs50.io/#ftw.h) - [ftw](https://manual.cs50.io/3/ftw) - file tree walk - [nftw](https://manual.cs50.io/3/nftw) - file tree walk # [glob.h](https://manual.cs50.io/#glob.h) - [glob](https://manual.cs50.io/3/glob) - find pathnames matching a pattern, free memory from gl... - [globfree](https://manual.cs50.io/3/globfree) - find pathnames matching a pattern, free memory from gl... # [grp.h](https://manual.cs50.io/#grp.h) - [fgetgrent\_r](https://manual.cs50.io/3/fgetgrent_r) - get group file entry reentrantly - [getgrent\_r](https://manual.cs50.io/3/getgrent_r) - get group file entry reentrantly - [getgrouplist](https://manual.cs50.io/3/getgrouplist) - get list of groups to which a user belongs - [putgrent](https://manual.cs50.io/3/putgrent) - write a group database entry to a file # [iconv.h](https://manual.cs50.io/#iconv.h) - [iconv](https://manual.cs50.io/3/iconv) - perform character set conversion - [iconv\_close](https://manual.cs50.io/3/iconv_close) - deallocate descriptor for character set conversion - [iconv\_open](https://manual.cs50.io/3/iconv_open) - allocate descriptor for character set conversion # [inttypes.h](https://manual.cs50.io/#inttypes.h) - [strtoimax](https://manual.cs50.io/3/strtoimax) - convert string to integer - [strtoumax](https://manual.cs50.io/3/strtoumax) - convert string to integer # [langinfo.h](https://manual.cs50.io/#langinfo.h) - [nl\_langinfo](https://manual.cs50.io/3/nl_langinfo) - query language and locale information - [nl\_langinfo\_l](https://manual.cs50.io/3/nl_langinfo_l) - query language and locale information # [libgen.h](https://manual.cs50.io/#libgen.h) - [basename](https://manual.cs50.io/3/basename) - parse pathname components - [dirname](https://manual.cs50.io/3/dirname) - parse pathname components # [limits.h](https://manual.cs50.io/#limits.h) - [MB\_LEN\_MAX](https://manual.cs50.io/3/MB_LEN_MAX) - maximum multibyte length of a character across all loc... - [realpath](https://manual.cs50.io/3/realpath) - return the canonicalized absolute pathname # [locale.h](https://manual.cs50.io/#locale.h) - [duplocale](https://manual.cs50.io/3/duplocale) - duplicate a locale object - [freelocale](https://manual.cs50.io/3/freelocale) - create, modify, and free a locale object - [locale](https://manual.cs50.io/7/locale) - description of multilanguage support - [localeconv](https://manual.cs50.io/3/localeconv) - get numeric formatting information - [newlocale](https://manual.cs50.io/3/newlocale) - create, modify, and free a locale object - [setlocale](https://manual.cs50.io/3/setlocale) - set the current locale - [uselocale](https://manual.cs50.io/3/uselocale) - set/get the locale for the calling thread # [math.h](https://manual.cs50.io/#math.h) - [acos](https://manual.cs50.io/3/acos) - arc cosine function - [acosf](https://manual.cs50.io/3/acosf) - arc cosine function - [acosh](https://manual.cs50.io/3/acosh) - inverse hyperbolic cosine function - [acoshf](https://manual.cs50.io/3/acoshf) - inverse hyperbolic cosine function - [acoshl](https://manual.cs50.io/3/acoshl) - inverse hyperbolic cosine function - [acosl](https://manual.cs50.io/3/acosl) - arc cosine function - [asin](https://manual.cs50.io/3/asin) - arc sine function - [asinf](https://manual.cs50.io/3/asinf) - arc sine function - [asinh](https://manual.cs50.io/3/asinh) - inverse hyperbolic sine function - [asinhf](https://manual.cs50.io/3/asinhf) - inverse hyperbolic sine function - [asinhl](https://manual.cs50.io/3/asinhl) - inverse hyperbolic sine function - [asinl](https://manual.cs50.io/3/asinl) - arc sine function - [atan](https://manual.cs50.io/3/atan) - arc tangent function - [atan2](https://manual.cs50.io/3/atan2) - arc tangent function of two variables - [atan2f](https://manual.cs50.io/3/atan2f) - arc tangent function of two variables - [atan2l](https://manual.cs50.io/3/atan2l) - arc tangent function of two variables - [atanf](https://manual.cs50.io/3/atanf) - arc tangent function - [atanh](https://manual.cs50.io/3/atanh) - inverse hyperbolic tangent function - [atanhf](https://manual.cs50.io/3/atanhf) - inverse hyperbolic tangent function - [atanhl](https://manual.cs50.io/3/atanhl) - inverse hyperbolic tangent function - [atanl](https://manual.cs50.io/3/atanl) - arc tangent function - [cbrt](https://manual.cs50.io/3/cbrt) - cube root function - [cbrtf](https://manual.cs50.io/3/cbrtf) - cube root function - [cbrtl](https://manual.cs50.io/3/cbrtl) - cube root function - [ceil](https://manual.cs50.io/3/ceil) - ceiling function: smallest integral value not less tha... calculate the ceiling of a number - [ceilf](https://manual.cs50.io/3/ceilf) - ceiling function: smallest integral value not less tha... - [ceill](https://manual.cs50.io/3/ceill) - ceiling function: smallest integral value not less tha... - [copysign](https://manual.cs50.io/3/copysign) - copy sign of a number - [copysignf](https://manual.cs50.io/3/copysignf) - copy sign of a number - [copysignl](https://manual.cs50.io/3/copysignl) - copy sign of a number - [cos](https://manual.cs50.io/3/cos) - cosine function - [cosf](https://manual.cs50.io/3/cosf) - cosine function - [cosh](https://manual.cs50.io/3/cosh) - hyperbolic cosine function - [coshf](https://manual.cs50.io/3/coshf) - hyperbolic cosine function - [coshl](https://manual.cs50.io/3/coshl) - hyperbolic cosine function - [cosl](https://manual.cs50.io/3/cosl) - cosine function - [drem](https://manual.cs50.io/3/drem) - floating-point remainder function - [dremf](https://manual.cs50.io/3/dremf) - floating-point remainder function - [dreml](https://manual.cs50.io/3/dreml) - floating-point remainder function - [erf](https://manual.cs50.io/3/erf) - error function - [erfc](https://manual.cs50.io/3/erfc) - complementary error function - [erfcf](https://manual.cs50.io/3/erfcf) - complementary error function - [erfcl](https://manual.cs50.io/3/erfcl) - complementary error function - [erff](https://manual.cs50.io/3/erff) - error function - [erfl](https://manual.cs50.io/3/erfl) - error function - [exp](https://manual.cs50.io/3/exp) - base-e exponential function - [exp10](https://manual.cs50.io/3/exp10) - base-10 exponential function - [exp10f](https://manual.cs50.io/3/exp10f) - base-10 exponential function - [exp10l](https://manual.cs50.io/3/exp10l) - base-10 exponential function - [exp2](https://manual.cs50.io/3/exp2) - base-2 exponential function - [exp2f](https://manual.cs50.io/3/exp2f) - base-2 exponential function - [exp2l](https://manual.cs50.io/3/exp2l) - base-2 exponential function - [expf](https://manual.cs50.io/3/expf) - base-e exponential function - [expl](https://manual.cs50.io/3/expl) - base-e exponential function - [expm1](https://manual.cs50.io/3/expm1) - exponential minus 1 - [expm1f](https://manual.cs50.io/3/expm1f) - exponential minus 1 - [expm1l](https://manual.cs50.io/3/expm1l) - exponential minus 1 - [fabs](https://manual.cs50.io/3/fabs) - absolute value of floating-point number - [fabsf](https://manual.cs50.io/3/fabsf) - absolute value of floating-point number - [fabsl](https://manual.cs50.io/3/fabsl) - absolute value of floating-point number - [fdim](https://manual.cs50.io/3/fdim) - positive difference - [fdimf](https://manual.cs50.io/3/fdimf) - positive difference - [fdiml](https://manual.cs50.io/3/fdiml) - positive difference - [finite](https://manual.cs50.io/3/finite) - BSD floating-point classification functions - [finitef](https://manual.cs50.io/3/finitef) - BSD floating-point classification functions - [finitel](https://manual.cs50.io/3/finitel) - BSD floating-point classification functions - [floor](https://manual.cs50.io/3/floor) - largest integral value not greater than argument calculate the floor of a number - [floorf](https://manual.cs50.io/3/floorf) - largest integral value not greater than argument - [floorl](https://manual.cs50.io/3/floorl) - largest integral value not greater than argument - [fma](https://manual.cs50.io/3/fma) - floating-point multiply and add - [fmaf](https://manual.cs50.io/3/fmaf) - floating-point multiply and add - [fmal](https://manual.cs50.io/3/fmal) - floating-point multiply and add - [fmax](https://manual.cs50.io/3/fmax) - determine maximum of two floating-point numbers - [fmaxf](https://manual.cs50.io/3/fmaxf) - determine maximum of two floating-point numbers - [fmaxl](https://manual.cs50.io/3/fmaxl) - determine maximum of two floating-point numbers - [fmin](https://manual.cs50.io/3/fmin) - determine minimum of two floating-point numbers - [fminf](https://manual.cs50.io/3/fminf) - determine minimum of two floating-point numbers - [fminl](https://manual.cs50.io/3/fminl) - determine minimum of two floating-point numbers - [fmod](https://manual.cs50.io/3/fmod) - floating-point remainder function - [fmodf](https://manual.cs50.io/3/fmodf) - floating-point remainder function - [fmodl](https://manual.cs50.io/3/fmodl) - floating-point remainder function - [fpclassify](https://manual.cs50.io/3/fpclassify) - floating-point classification macros - [frexp](https://manual.cs50.io/3/frexp) - convert floating-point number to fractional and integr... - [frexpf](https://manual.cs50.io/3/frexpf) - convert floating-point number to fractional and integr... - [frexpl](https://manual.cs50.io/3/frexpl) - convert floating-point number to fractional and integr... - [gamma](https://manual.cs50.io/3/gamma) - (logarithm of the) gamma function - [gammaf](https://manual.cs50.io/3/gammaf) - (logarithm of the) gamma function - [gammal](https://manual.cs50.io/3/gammal) - (logarithm of the) gamma function - [HUGE\_VAL](https://manual.cs50.io/3/HUGE_VAL) - floating-point constants - [HUGE\_VALF](https://manual.cs50.io/3/HUGE_VALF) - floating-point constants - [HUGE\_VALL](https://manual.cs50.io/3/HUGE_VALL) - floating-point constants - [hypot](https://manual.cs50.io/3/hypot) - Euclidean distance function - [hypotf](https://manual.cs50.io/3/hypotf) - Euclidean distance function - [hypotl](https://manual.cs50.io/3/hypotl) - Euclidean distance function - [ilogb](https://manual.cs50.io/3/ilogb) - get integer exponent of a floating-point value - [ilogbf](https://manual.cs50.io/3/ilogbf) - get integer exponent of a floating-point value - [ilogbl](https://manual.cs50.io/3/ilogbl) - get integer exponent of a floating-point value - [INFINITY](https://manual.cs50.io/3/INFINITY) - floating-point constants - [isfinite](https://manual.cs50.io/3/isfinite) - floating-point classification macros - [isgreater](https://manual.cs50.io/3/isgreater) - floating-point relational tests without exception for NaN - [isgreaterequal](https://manual.cs50.io/3/isgreaterequal) - floating-point relational tests without exception for NaN - [isinf](https://manual.cs50.io/3/isinf) - floating-point classification macros - [isinff](https://manual.cs50.io/3/isinff) - BSD floating-point classification functions - [isinfl](https://manual.cs50.io/3/isinfl) - BSD floating-point classification functions - [isless](https://manual.cs50.io/3/isless) - floating-point relational tests without exception for NaN - [islessequal](https://manual.cs50.io/3/islessequal) - floating-point relational tests without exception for NaN - [islessgreater](https://manual.cs50.io/3/islessgreater) - floating-point relational tests without exception for NaN - [isnan](https://manual.cs50.io/3/isnan) - floating-point classification macros - [isnanf](https://manual.cs50.io/3/isnanf) - BSD floating-point classification functions - [isnanl](https://manual.cs50.io/3/isnanl) - BSD floating-point classification functions - [isnormal](https://manual.cs50.io/3/isnormal) - floating-point classification macros - [isunordered](https://manual.cs50.io/3/isunordered) - floating-point relational tests without exception for NaN - [j0](https://manual.cs50.io/3/j0) - Bessel functions of the first kind - [j0f](https://manual.cs50.io/3/j0f) - Bessel functions of the first kind - [j0l](https://manual.cs50.io/3/j0l) - Bessel functions of the first kind - [j1](https://manual.cs50.io/3/j1) - Bessel functions of the first kind - [j1f](https://manual.cs50.io/3/j1f) - Bessel functions of the first kind - [j1l](https://manual.cs50.io/3/j1l) - Bessel functions of the first kind - [jn](https://manual.cs50.io/3/jn) - Bessel functions of the first kind - [jnf](https://manual.cs50.io/3/jnf) - Bessel functions of the first kind - [jnl](https://manual.cs50.io/3/jnl) - Bessel functions of the first kind - [ldexp](https://manual.cs50.io/3/ldexp) - multiply floating-point number by integral power of 2 - [ldexpf](https://manual.cs50.io/3/ldexpf) - multiply floating-point number by integral power of 2 - [ldexpl](https://manual.cs50.io/3/ldexpl) - multiply floating-point number by integral power of 2 - [lgamma](https://manual.cs50.io/3/lgamma) - log gamma function - [lgamma\_r](https://manual.cs50.io/3/lgamma_r) - log gamma function - [lgammaf](https://manual.cs50.io/3/lgammaf) - log gamma function - [lgammaf\_r](https://manual.cs50.io/3/lgammaf_r) - log gamma function - [lgammal](https://manual.cs50.io/3/lgammal) - log gamma function - [lgammal\_r](https://manual.cs50.io/3/lgammal_r) - log gamma function - [llrint](https://manual.cs50.io/3/llrint) - round to nearest integer - [llrintf](https://manual.cs50.io/3/llrintf) - round to nearest integer - [llrintl](https://manual.cs50.io/3/llrintl) - round to nearest integer - [llround](https://manual.cs50.io/3/llround) - round to nearest integer - [llroundf](https://manual.cs50.io/3/llroundf) - round to nearest integer - [llroundl](https://manual.cs50.io/3/llroundl) - round to nearest integer - [log](https://manual.cs50.io/3/log) - natural logarithmic function - [log10](https://manual.cs50.io/3/log10) - base-10 logarithmic function - [log10f](https://manual.cs50.io/3/log10f) - base-10 logarithmic function - [log10l](https://manual.cs50.io/3/log10l) - base-10 logarithmic function - [log1p](https://manual.cs50.io/3/log1p) - logarithm of 1 plus argument - [log1pf](https://manual.cs50.io/3/log1pf) - logarithm of 1 plus argument - [log1pl](https://manual.cs50.io/3/log1pl) - logarithm of 1 plus argument - [log2](https://manual.cs50.io/3/log2) - base-2 logarithmic function calculate the base-2 logarithm of a number - [log2f](https://manual.cs50.io/3/log2f) - base-2 logarithmic function - [log2l](https://manual.cs50.io/3/log2l) - base-2 logarithmic function - [logb](https://manual.cs50.io/3/logb) - get exponent of a floating-point value - [logbf](https://manual.cs50.io/3/logbf) - get exponent of a floating-point value - [logbl](https://manual.cs50.io/3/logbl) - get exponent of a floating-point value - [logf](https://manual.cs50.io/3/logf) - natural logarithmic function - [logl](https://manual.cs50.io/3/logl) - natural logarithmic function - [lrint](https://manual.cs50.io/3/lrint) - round to nearest integer - [lrintf](https://manual.cs50.io/3/lrintf) - round to nearest integer - [lrintl](https://manual.cs50.io/3/lrintl) - round to nearest integer - [lround](https://manual.cs50.io/3/lround) - round to nearest integer - [lroundf](https://manual.cs50.io/3/lroundf) - round to nearest integer - [lroundl](https://manual.cs50.io/3/lroundl) - round to nearest integer - [math\_error](https://manual.cs50.io/7/math_error) - detecting errors from mathematical functions - [matherr](https://manual.cs50.io/3/matherr) - SVID math library exception handling - [modf](https://manual.cs50.io/3/modf) - extract signed integral and fractional values from flo... - [modff](https://manual.cs50.io/3/modff) - extract signed integral and fractional values from flo... - [modfl](https://manual.cs50.io/3/modfl) - extract signed integral and fractional values from flo... - [NAN](https://manual.cs50.io/3/NAN) - floating-point constants - [nan](https://manual.cs50.io/3/nan) - return 'Not a Number' - [nanf](https://manual.cs50.io/3/nanf) - return 'Not a Number' - [nanl](https://manual.cs50.io/3/nanl) - return 'Not a Number' - [nearbyint](https://manual.cs50.io/3/nearbyint) - round to nearest integer - [nearbyintf](https://manual.cs50.io/3/nearbyintf) - round to nearest integer - [nearbyintl](https://manual.cs50.io/3/nearbyintl) - round to nearest integer - [nextafter](https://manual.cs50.io/3/nextafter) - floating-point number manipulation - [nextafterf](https://manual.cs50.io/3/nextafterf) - floating-point number manipulation - [nextafterl](https://manual.cs50.io/3/nextafterl) - floating-point number manipulation - [nextdown](https://manual.cs50.io/3/nextdown) - return next floating-point number toward positive/nega... - [nextdownf](https://manual.cs50.io/3/nextdownf) - return next floating-point number toward positive/nega... - [nextdownl](https://manual.cs50.io/3/nextdownl) - return next floating-point number toward positive/nega... - [nexttoward](https://manual.cs50.io/3/nexttoward) - floating-point number manipulation - [nexttowardf](https://manual.cs50.io/3/nexttowardf) - floating-point number manipulation - [nexttowardl](https://manual.cs50.io/3/nexttowardl) - floating-point number manipulation - [nextup](https://manual.cs50.io/3/nextup) - return next floating-point number toward positive/nega... - [nextupf](https://manual.cs50.io/3/nextupf) - return next floating-point number toward positive/nega... - [nextupl](https://manual.cs50.io/3/nextupl) - return next floating-point number toward positive/nega... - [pow](https://manual.cs50.io/3/pow) - power functions raise a number to a power - [pow10](https://manual.cs50.io/3/pow10) - base-10 power functions - [pow10f](https://manual.cs50.io/3/pow10f) - base-10 power functions - [pow10l](https://manual.cs50.io/3/pow10l) - base-10 power functions - [powf](https://manual.cs50.io/3/powf) - power functions - [powl](https://manual.cs50.io/3/powl) - power functions - [remainder](https://manual.cs50.io/3/remainder) - floating-point remainder function - [remainderf](https://manual.cs50.io/3/remainderf) - floating-point remainder function - [remainderl](https://manual.cs50.io/3/remainderl) - floating-point remainder function - [remquo](https://manual.cs50.io/3/remquo) - remainder and part of quotient - [remquof](https://manual.cs50.io/3/remquof) - remainder and part of quotient - [remquol](https://manual.cs50.io/3/remquol) - remainder and part of quotient - [rint](https://manual.cs50.io/3/rint) - round to nearest integer - [rintf](https://manual.cs50.io/3/rintf) - round to nearest integer - [rintl](https://manual.cs50.io/3/rintl) - round to nearest integer - [round](https://manual.cs50.io/3/round) - round to nearest integer, away from zero round a number to the nearest integer - [roundf](https://manual.cs50.io/3/roundf) - round to nearest integer, away from zero - [roundl](https://manual.cs50.io/3/roundl) - round to nearest integer, away from zero - [scalb](https://manual.cs50.io/3/scalb) - multiply floating-point number by integral power of ra... - [scalbf](https://manual.cs50.io/3/scalbf) - multiply floating-point number by integral power of ra... - [scalbl](https://manual.cs50.io/3/scalbl) - multiply floating-point number by integral power of ra... - [scalbln](https://manual.cs50.io/3/scalbln) - multiply floating-point number by integral power of radix - [scalblnf](https://manual.cs50.io/3/scalblnf) - multiply floating-point number by integral power of radix - [scalblnl](https://manual.cs50.io/3/scalblnl) - multiply floating-point number by integral power of radix - [scalbn](https://manual.cs50.io/3/scalbn) - multiply floating-point number by integral power of radix - [scalbnf](https://manual.cs50.io/3/scalbnf) - multiply floating-point number by integral power of radix - [scalbnl](https://manual.cs50.io/3/scalbnl) - multiply floating-point number by integral power of radix - [signbit](https://manual.cs50.io/3/signbit) - test sign of a real floating-point number - [signgam](https://manual.cs50.io/3/signgam) - log gamma function - [significand](https://manual.cs50.io/3/significand) - get mantissa of floating-point number - [significandf](https://manual.cs50.io/3/significandf) - get mantissa of floating-point number - [significandl](https://manual.cs50.io/3/significandl) - get mantissa of floating-point number - [sin](https://manual.cs50.io/3/sin) - sine function - [sincos](https://manual.cs50.io/3/sincos) - calculate sin and cos simultaneously - [sincosf](https://manual.cs50.io/3/sincosf) - calculate sin and cos simultaneously - [sincosl](https://manual.cs50.io/3/sincosl) - calculate sin and cos simultaneously - [sinf](https://manual.cs50.io/3/sinf) - sine function - [sinh](https://manual.cs50.io/3/sinh) - hyperbolic sine function - [sinhf](https://manual.cs50.io/3/sinhf) - hyperbolic sine function - [sinhl](https://manual.cs50.io/3/sinhl) - hyperbolic sine function - [sinl](https://manual.cs50.io/3/sinl) - sine function - [sqrt](https://manual.cs50.io/3/sqrt) - square root function calculate the square root of a number - [sqrtf](https://manual.cs50.io/3/sqrtf) - square root function - [sqrtl](https://manual.cs50.io/3/sqrtl) - square root function - [tan](https://manual.cs50.io/3/tan) - tangent function - [tanf](https://manual.cs50.io/3/tanf) - tangent function - [tanh](https://manual.cs50.io/3/tanh) - hyperbolic tangent function - [tanhf](https://manual.cs50.io/3/tanhf) - hyperbolic tangent function - [tanhl](https://manual.cs50.io/3/tanhl) - hyperbolic tangent function - [tanl](https://manual.cs50.io/3/tanl) - tangent function - [tgamma](https://manual.cs50.io/3/tgamma) - true gamma function - [tgammaf](https://manual.cs50.io/3/tgammaf) - true gamma function - [tgammal](https://manual.cs50.io/3/tgammal) - true gamma function - [trunc](https://manual.cs50.io/3/trunc) - round to integer, toward zero - [truncf](https://manual.cs50.io/3/truncf) - round to integer, toward zero - [truncl](https://manual.cs50.io/3/truncl) - round to integer, toward zero - [y0](https://manual.cs50.io/3/y0) - Bessel functions of the second kind - [y0f](https://manual.cs50.io/3/y0f) - Bessel functions of the second kind - [y0l](https://manual.cs50.io/3/y0l) - Bessel functions of the second kind - [y1](https://manual.cs50.io/3/y1) - Bessel functions of the second kind - [y1f](https://manual.cs50.io/3/y1f) - Bessel functions of the second kind - [y1l](https://manual.cs50.io/3/y1l) - Bessel functions of the second kind - [yn](https://manual.cs50.io/3/yn) - Bessel functions of the second kind - [ynf](https://manual.cs50.io/3/ynf) - Bessel functions of the second kind - [ynl](https://manual.cs50.io/3/ynl) - Bessel functions of the second kind # [monetary.h](https://manual.cs50.io/#monetary.h) - [strfmon](https://manual.cs50.io/3/strfmon) - convert monetary value to a string - [strfmon\_l](https://manual.cs50.io/3/strfmon_l) - convert monetary value to a string # [mqueue.h](https://manual.cs50.io/#mqueue.h) - [mq\_close](https://manual.cs50.io/3/mq_close) - close a message queue descriptor - [mq\_getattr](https://manual.cs50.io/3/mq_getattr) - get/set message queue attributes - [mq\_notify](https://manual.cs50.io/2/mq_notify) - register for notification when a message is available - [mq\_notify](https://manual.cs50.io/3/mq_notify) - register for notification when a message is available - [mq\_open](https://manual.cs50.io/2/mq_open) - open a message queue - [mq\_open](https://manual.cs50.io/3/mq_open) - open a message queue - [mq\_receive](https://manual.cs50.io/3/mq_receive) - receive a message from a message queue - [mq\_send](https://manual.cs50.io/3/mq_send) - send a message to a message queue - [mq\_setattr](https://manual.cs50.io/3/mq_setattr) - get/set message queue attributes - [mq\_timedreceive](https://manual.cs50.io/2/mq_timedreceive) - receive a message from a message queue - [mq\_timedreceive](https://manual.cs50.io/3/mq_timedreceive) - receive a message from a message queue - [mq\_timedsend](https://manual.cs50.io/2/mq_timedsend) - send a message to a message queue - [mq\_timedsend](https://manual.cs50.io/3/mq_timedsend) - send a message to a message queue - [mq\_unlink](https://manual.cs50.io/2/mq_unlink) - remove a message queue - [mq\_unlink](https://manual.cs50.io/3/mq_unlink) - remove a message queue # [net/if.h](https://manual.cs50.io/#net/if.h) - [if\_freenameindex](https://manual.cs50.io/3/if_freenameindex) - get network interface names and indexes - [if\_indextoname](https://manual.cs50.io/3/if_indextoname) - mappings between network interface names and indexes - [if\_nameindex](https://manual.cs50.io/3/if_nameindex) - get network interface names and indexes - [if\_nametoindex](https://manual.cs50.io/3/if_nametoindex) - mappings between network interface names and indexes # [netdb.h](https://manual.cs50.io/#netdb.h) - [endhostent](https://manual.cs50.io/3/endhostent) - get network host entry - [endnetent](https://manual.cs50.io/3/endnetent) - get network entry - [endnetgrent](https://manual.cs50.io/3/endnetgrent) - handle network group entries - [endprotoent](https://manual.cs50.io/3/endprotoent) - get protocol entry - [endrpcent](https://manual.cs50.io/3/endrpcent) - get RPC entry - [endservent](https://manual.cs50.io/3/endservent) - get service entry - [gai\_cancel](https://manual.cs50.io/3/gai_cancel) - asynchronous network address and service translation - [gai\_error](https://manual.cs50.io/3/gai_error) - asynchronous network address and service translation - [gai\_suspend](https://manual.cs50.io/3/gai_suspend) - asynchronous network address and service translation - [getaddrinfo\_a](https://manual.cs50.io/3/getaddrinfo_a) - asynchronous network address and service translation - [gethostbyaddr](https://manual.cs50.io/3/gethostbyaddr) - get network host entry - [gethostbyaddr\_r](https://manual.cs50.io/3/gethostbyaddr_r) - get network host entry - [gethostbyname](https://manual.cs50.io/3/gethostbyname) - get network host entry - [gethostbyname2](https://manual.cs50.io/3/gethostbyname2) - get network host entry - [gethostbyname2\_r](https://manual.cs50.io/3/gethostbyname2_r) - get network host entry - [gethostbyname\_r](https://manual.cs50.io/3/gethostbyname_r) - get network host entry - [gethostent](https://manual.cs50.io/3/gethostent) - get network host entry - [gethostent\_r](https://manual.cs50.io/3/gethostent_r) - get network host entry - [getnetbyaddr](https://manual.cs50.io/3/getnetbyaddr) - get network entry - [getnetbyaddr\_r](https://manual.cs50.io/3/getnetbyaddr_r) - get network entry (reentrant) - [getnetbyname](https://manual.cs50.io/3/getnetbyname) - get network entry - [getnetbyname\_r](https://manual.cs50.io/3/getnetbyname_r) - get network entry (reentrant) - [getnetent](https://manual.cs50.io/3/getnetent) - get network entry - [getnetent\_r](https://manual.cs50.io/3/getnetent_r) - get network entry (reentrant) - [getnetgrent](https://manual.cs50.io/3/getnetgrent) - handle network group entries - [getnetgrent\_r](https://manual.cs50.io/3/getnetgrent_r) - handle network group entries - [getprotobyname](https://manual.cs50.io/3/getprotobyname) - get protocol entry - [getprotobyname\_r](https://manual.cs50.io/3/getprotobyname_r) - get protocol entry (reentrant) - [getprotobynumber](https://manual.cs50.io/3/getprotobynumber) - get protocol entry - [getprotobynumber\_r](https://manual.cs50.io/3/getprotobynumber_r) - get protocol entry (reentrant) - [getprotoent](https://manual.cs50.io/3/getprotoent) - get protocol entry - [getprotoent\_r](https://manual.cs50.io/3/getprotoent_r) - get protocol entry (reentrant) - [getrpcbyname](https://manual.cs50.io/3/getrpcbyname) - get RPC entry - [getrpcbyname\_r](https://manual.cs50.io/3/getrpcbyname_r) - get RPC entry (reentrant) - [getrpcbynumber](https://manual.cs50.io/3/getrpcbynumber) - get RPC entry - [getrpcbynumber\_r](https://manual.cs50.io/3/getrpcbynumber_r) - get RPC entry (reentrant) - [getrpcent](https://manual.cs50.io/3/getrpcent) - get RPC entry - [getrpcent\_r](https://manual.cs50.io/3/getrpcent_r) - get RPC entry (reentrant) - [getservbyname](https://manual.cs50.io/3/getservbyname) - get service entry - [getservbyname\_r](https://manual.cs50.io/3/getservbyname_r) - get service entry (reentrant) - [getservbyport](https://manual.cs50.io/3/getservbyport) - get service entry - [getservbyport\_r](https://manual.cs50.io/3/getservbyport_r) - get service entry (reentrant) - [getservent](https://manual.cs50.io/3/getservent) - get service entry - [getservent\_r](https://manual.cs50.io/3/getservent_r) - get service entry (reentrant) - [h\_errno](https://manual.cs50.io/3/h_errno) - get network host entry - [herror](https://manual.cs50.io/3/herror) - get network host entry - [hstrerror](https://manual.cs50.io/3/hstrerror) - get network host entry - [innetgr](https://manual.cs50.io/3/innetgr) - handle network group entries - [rexec](https://manual.cs50.io/3/rexec) - return stream to a remote command - [rexec\_af](https://manual.cs50.io/3/rexec_af) - return stream to a remote command - [sethostent](https://manual.cs50.io/3/sethostent) - get network host entry - [setnetent](https://manual.cs50.io/3/setnetent) - get network entry - [setnetgrent](https://manual.cs50.io/3/setnetgrent) - handle network group entries - [setprotoent](https://manual.cs50.io/3/setprotoent) - get protocol entry - [setrpcent](https://manual.cs50.io/3/setrpcent) - get RPC entry - [setservent](https://manual.cs50.io/3/setservent) - get service entry # [netinet/in.h](https://manual.cs50.io/#netinet/in.h) - [dn\_comp](https://manual.cs50.io/3/dn_comp) - resolver routines - [dn\_expand](https://manual.cs50.io/3/dn_expand) - resolver routines - [res\_init](https://manual.cs50.io/3/res_init) - resolver routines - [res\_mkquery](https://manual.cs50.io/3/res_mkquery) - resolver routines - [res\_nclose](https://manual.cs50.io/3/res_nclose) - resolver routines - [res\_ninit](https://manual.cs50.io/3/res_ninit) - resolver routines - [res\_nmkquery](https://manual.cs50.io/3/res_nmkquery) - resolver routines - [res\_nquery](https://manual.cs50.io/3/res_nquery) - resolver routines - [res\_nquerydomain](https://manual.cs50.io/3/res_nquerydomain) - resolver routines - [res\_nsearch](https://manual.cs50.io/3/res_nsearch) - resolver routines - [res\_nsend](https://manual.cs50.io/3/res_nsend) - resolver routines - [res\_query](https://manual.cs50.io/3/res_query) - resolver routines - [res\_querydomain](https://manual.cs50.io/3/res_querydomain) - resolver routines - [res\_search](https://manual.cs50.io/3/res_search) - resolver routines - [res\_send](https://manual.cs50.io/3/res_send) - resolver routines - [resolver](https://manual.cs50.io/3/resolver) - resolver routines # [nl\_types.h](https://manual.cs50.io/#nl_types.h) - [catclose](https://manual.cs50.io/3/catclose) - open/close a message catalog - [catgets](https://manual.cs50.io/3/catgets) - get message from a message catalog - [catopen](https://manual.cs50.io/3/catopen) - open/close a message catalog # [poll.h](https://manual.cs50.io/#poll.h) - [poll](https://manual.cs50.io/2/poll) - wait for some event on a file descriptor - [ppoll](https://manual.cs50.io/2/ppoll) - wait for some event on a file descriptor # [pthread.h](https://manual.cs50.io/#pthread.h) - [pthread\_attr\_destroy](https://manual.cs50.io/3/pthread_attr_destroy) - initialize and destroy thread attributes object - [pthread\_attr\_getaffinity\_np](https://manual.cs50.io/3/pthread_attr_getaffinity_np) - set/get CPU affinity attribute in thread at... - [pthread\_attr\_getdetachstate](https://manual.cs50.io/3/pthread_attr_getdetachstate) - set/get detach state attribute in thread at... - [pthread\_attr\_getguardsize](https://manual.cs50.io/3/pthread_attr_getguardsize) - set/get guard size attribute in thread attrib... - [pthread\_attr\_getinheritsched](https://manual.cs50.io/3/pthread_attr_getinheritsched) - set/get inherit-scheduler attribute in thr... - [pthread\_attr\_getschedparam](https://manual.cs50.io/3/pthread_attr_getschedparam) - set/get scheduling parameter attributes in t... - [pthread\_attr\_getschedpolicy](https://manual.cs50.io/3/pthread_attr_getschedpolicy) - set/get scheduling policy attribute in thre... - [pthread\_attr\_getscope](https://manual.cs50.io/3/pthread_attr_getscope) - set/get contention scope attribute in thread attr... - [pthread\_attr\_getsigmask\_np](https://manual.cs50.io/3/pthread_attr_getsigmask_np) - set/get signal mask attribute in thread attr... - [pthread\_attr\_getstack](https://manual.cs50.io/3/pthread_attr_getstack) - set/get stack attributes in thread attributes object - [pthread\_attr\_getstackaddr](https://manual.cs50.io/3/pthread_attr_getstackaddr) - set/get stack address attribute in thread att... - [pthread\_attr\_getstacksize](https://manual.cs50.io/3/pthread_attr_getstacksize) - set/get stack size attribute in thread attrib... - [pthread\_attr\_init](https://manual.cs50.io/3/pthread_attr_init) - initialize and destroy thread attributes object - [pthread\_attr\_setaffinity\_np](https://manual.cs50.io/3/pthread_attr_setaffinity_np) - set/get CPU affinity attribute in thread at... - [pthread\_attr\_setdetachstate](https://manual.cs50.io/3/pthread_attr_setdetachstate) - set/get detach state attribute in thread at... - [pthread\_attr\_setguardsize](https://manual.cs50.io/3/pthread_attr_setguardsize) - set/get guard size attribute in thread attrib... - [pthread\_attr\_setinheritsched](https://manual.cs50.io/3/pthread_attr_setinheritsched) - set/get inherit-scheduler attribute in thr... - [pthread\_attr\_setschedparam](https://manual.cs50.io/3/pthread_attr_setschedparam) - set/get scheduling parameter attributes in t... - [pthread\_attr\_setschedpolicy](https://manual.cs50.io/3/pthread_attr_setschedpolicy) - set/get scheduling policy attribute in thre... - [pthread\_attr\_setscope](https://manual.cs50.io/3/pthread_attr_setscope) - set/get contention scope attribute in thread attr... - [pthread\_attr\_setsigmask\_np](https://manual.cs50.io/3/pthread_attr_setsigmask_np) - set/get signal mask attribute in thread attr... - [pthread\_attr\_setstack](https://manual.cs50.io/3/pthread_attr_setstack) - set/get stack attributes in thread attributes object - [pthread\_attr\_setstackaddr](https://manual.cs50.io/3/pthread_attr_setstackaddr) - set/get stack address attribute in thread att... - [pthread\_attr\_setstacksize](https://manual.cs50.io/3/pthread_attr_setstacksize) - set/get stack size attribute in thread attrib... - [pthread\_cancel](https://manual.cs50.io/3/pthread_cancel) - send a cancelation request to a thread - [pthread\_cleanup\_pop](https://manual.cs50.io/3/pthread_cleanup_pop) - push and pop thread cancelation clean-up handlers - [pthread\_cleanup\_pop\_restore\_np](https://manual.cs50.io/3/pthread_cleanup_pop_restore_np) - push and pop thread cancelation clean-up... - [pthread\_cleanup\_push](https://manual.cs50.io/3/pthread_cleanup_push) - push and pop thread cancelation clean-up handlers - [pthread\_cleanup\_push\_defer\_np](https://manual.cs50.io/3/pthread_cleanup_push_defer_np) - push and pop thread cancelation clean-up ... - [pthread\_create](https://manual.cs50.io/3/pthread_create) - create a new thread - [pthread\_detach](https://manual.cs50.io/3/pthread_detach) - detach a thread - [pthread\_equal](https://manual.cs50.io/3/pthread_equal) - compare thread IDs - [pthread\_exit](https://manual.cs50.io/3/pthread_exit) - terminate calling thread - [pthread\_getaffinity\_np](https://manual.cs50.io/3/pthread_getaffinity_np) - set/get CPU affinity of a thread - [pthread\_getattr\_default\_np](https://manual.cs50.io/3/pthread_getattr_default_np) - get or set default thread-creation attributes - [pthread\_getattr\_np](https://manual.cs50.io/3/pthread_getattr_np) - get attributes of created thread - [pthread\_getconcurrency](https://manual.cs50.io/3/pthread_getconcurrency) - set/get the concurrency level - [pthread\_getcpuclockid](https://manual.cs50.io/3/pthread_getcpuclockid) - retrieve ID of a thread's CPU time clock - [pthread\_getname\_np](https://manual.cs50.io/3/pthread_getname_np) - set/get the name of a thread - [pthread\_getschedparam](https://manual.cs50.io/3/pthread_getschedparam) - set/get scheduling policy and parameters of a thread - [pthread\_join](https://manual.cs50.io/3/pthread_join) - join with a terminated thread - [pthread\_kill\_other\_threads\_np](https://manual.cs50.io/3/pthread_kill_other_threads_np) - terminate all other threads in process - [pthread\_mutex\_consistent](https://manual.cs50.io/3/pthread_mutex_consistent) - make a robust mutex consistent - [pthread\_mutex\_consistent\_np](https://manual.cs50.io/3/pthread_mutex_consistent_np) - make a robust mutex consistent - [pthread\_mutexattr\_getpshared](https://manual.cs50.io/3/pthread_mutexattr_getpshared) - get/set process-shared mutex attribute - [pthread\_mutexattr\_getrobust](https://manual.cs50.io/3/pthread_mutexattr_getrobust) - get and set the robustness attribute of a m... - [pthread\_mutexattr\_getrobust\_np](https://manual.cs50.io/3/pthread_mutexattr_getrobust_np) - get and set the robustness attribute of ... - [pthread\_mutexattr\_setpshared](https://manual.cs50.io/3/pthread_mutexattr_setpshared) - get/set process-shared mutex attribute - [pthread\_mutexattr\_setrobust](https://manual.cs50.io/3/pthread_mutexattr_setrobust) - get and set the robustness attribute of a m... - [pthread\_mutexattr\_setrobust\_np](https://manual.cs50.io/3/pthread_mutexattr_setrobust_np) - get and set the robustness attribute of ... - [pthread\_rwlockattr\_getkind\_np](https://manual.cs50.io/3/pthread_rwlockattr_getkind_np) - set/get the read-write lock kind of the t... - [pthread\_rwlockattr\_setkind\_np](https://manual.cs50.io/3/pthread_rwlockattr_setkind_np) - set/get the read-write lock kind of the t... - [pthread\_self](https://manual.cs50.io/3/pthread_self) - obtain ID of the calling thread - [pthread\_setaffinity\_np](https://manual.cs50.io/3/pthread_setaffinity_np) - set/get CPU affinity of a thread - [pthread\_setattr\_default\_np](https://manual.cs50.io/3/pthread_setattr_default_np) - get or set default thread-creation attributes - [pthread\_setcancelstate](https://manual.cs50.io/3/pthread_setcancelstate) - set cancelability state and type - [pthread\_setcanceltype](https://manual.cs50.io/3/pthread_setcanceltype) - set cancelability state and type - [pthread\_setconcurrency](https://manual.cs50.io/3/pthread_setconcurrency) - set/get the concurrency level - [pthread\_setname\_np](https://manual.cs50.io/3/pthread_setname_np) - set/get the name of a thread - [pthread\_setschedparam](https://manual.cs50.io/3/pthread_setschedparam) - set/get scheduling policy and parameters of a thread - [pthread\_setschedprio](https://manual.cs50.io/3/pthread_setschedprio) - set scheduling priority of a thread - [pthread\_spin\_destroy](https://manual.cs50.io/3/pthread_spin_destroy) - initialize or destroy a spin lock - [pthread\_spin\_init](https://manual.cs50.io/3/pthread_spin_init) - initialize or destroy a spin lock - [pthread\_spin\_lock](https://manual.cs50.io/3/pthread_spin_lock) - lock and unlock a spin lock - [pthread\_spin\_trylock](https://manual.cs50.io/3/pthread_spin_trylock) - lock and unlock a spin lock - [pthread\_spin\_unlock](https://manual.cs50.io/3/pthread_spin_unlock) - lock and unlock a spin lock - [pthread\_testcancel](https://manual.cs50.io/3/pthread_testcancel) - request delivery of any pending cancelation request - [pthread\_timedjoin\_np](https://manual.cs50.io/3/pthread_timedjoin_np) - try to join with a terminated thread - [pthread\_tryjoin\_np](https://manual.cs50.io/3/pthread_tryjoin_np) - try to join with a terminated thread - [pthread\_yield](https://manual.cs50.io/3/pthread_yield) - yield the processor # [pwd.h](https://manual.cs50.io/#pwd.h) - [fgetpwent\_r](https://manual.cs50.io/3/fgetpwent_r) - get passwd file entry reentrantly - [getpwent\_r](https://manual.cs50.io/3/getpwent_r) - get passwd file entry reentrantly # [regex.h](https://manual.cs50.io/#regex.h) - [regcomp](https://manual.cs50.io/3/regcomp) - POSIX regex functions - [regerror](https://manual.cs50.io/3/regerror) - POSIX regex functions - [regex](https://manual.cs50.io/3/regex) - POSIX regex functions - [regexec](https://manual.cs50.io/3/regexec) - POSIX regex functions - [regfree](https://manual.cs50.io/3/regfree) - POSIX regex functions # [sched.h](https://manual.cs50.io/#sched.h) - [\_\_clone2](https://manual.cs50.io/2/__clone2) - create a child process - [clone](https://manual.cs50.io/2/clone) - create a child process - [clone2](https://manual.cs50.io/2/clone2) - create a child process - [clone3](https://manual.cs50.io/2/clone3) - create a child process - [CPU\_ALLOC](https://manual.cs50.io/3/CPU_ALLOC) - macros for manipulating CPU sets - [CPU\_ALLOC\_SIZE](https://manual.cs50.io/3/CPU_ALLOC_SIZE) - macros for manipulating CPU sets - [CPU\_AND](https://manual.cs50.io/3/CPU_AND) - macros for manipulating CPU sets - [CPU\_AND\_S](https://manual.cs50.io/3/CPU_AND_S) - macros for manipulating CPU sets - [CPU\_CLR](https://manual.cs50.io/3/CPU_CLR) - macros for manipulating CPU sets - [CPU\_CLR\_S](https://manual.cs50.io/3/CPU_CLR_S) - macros for manipulating CPU sets - [CPU\_COUNT](https://manual.cs50.io/3/CPU_COUNT) - macros for manipulating CPU sets - [CPU\_COUNT\_S](https://manual.cs50.io/3/CPU_COUNT_S) - macros for manipulating CPU sets - [CPU\_EQUAL](https://manual.cs50.io/3/CPU_EQUAL) - macros for manipulating CPU sets - [CPU\_EQUAL\_S](https://manual.cs50.io/3/CPU_EQUAL_S) - macros for manipulating CPU sets - [CPU\_FREE](https://manual.cs50.io/3/CPU_FREE) - macros for manipulating CPU sets - [CPU\_ISSET](https://manual.cs50.io/3/CPU_ISSET) - macros for manipulating CPU sets - [CPU\_ISSET\_S](https://manual.cs50.io/3/CPU_ISSET_S) - macros for manipulating CPU sets - [CPU\_OR](https://manual.cs50.io/3/CPU_OR) - macros for manipulating CPU sets - [CPU\_OR\_S](https://manual.cs50.io/3/CPU_OR_S) - macros for manipulating CPU sets - [CPU\_SET](https://manual.cs50.io/3/CPU_SET) - macros for manipulating CPU sets - [CPU\_SET\_S](https://manual.cs50.io/3/CPU_SET_S) - macros for manipulating CPU sets - [CPU\_XOR](https://manual.cs50.io/3/CPU_XOR) - macros for manipulating CPU sets - [CPU\_XOR\_S](https://manual.cs50.io/3/CPU_XOR_S) - macros for manipulating CPU sets - [CPU\_ZERO](https://manual.cs50.io/3/CPU_ZERO) - macros for manipulating CPU sets - [CPU\_ZERO\_S](https://manual.cs50.io/3/CPU_ZERO_S) - macros for manipulating CPU sets - [getcpu](https://manual.cs50.io/2/getcpu) - determine CPU and NUMA node on which the calling threa... - [sched\_get\_priority\_max](https://manual.cs50.io/2/sched_get_priority_max) - get static priority range - [sched\_get\_priority\_min](https://manual.cs50.io/2/sched_get_priority_min) - get static priority range - [sched\_getaffinity](https://manual.cs50.io/2/sched_getaffinity) - set and get a thread's CPU affinity mask - [sched\_getcpu](https://manual.cs50.io/3/sched_getcpu) - determine CPU on which the calling thread is running - [sched\_getparam](https://manual.cs50.io/2/sched_getparam) - set and get scheduling parameters - [sched\_getscheduler](https://manual.cs50.io/2/sched_getscheduler) - set and get scheduling policy/parameters - [sched\_rr\_get\_interval](https://manual.cs50.io/2/sched_rr_get_interval) - get the SCHED\_RR interval for the named process - [sched\_setaffinity](https://manual.cs50.io/2/sched_setaffinity) - set and get a thread's CPU affinity mask - [sched\_setparam](https://manual.cs50.io/2/sched_setparam) - set and get scheduling parameters - [sched\_setscheduler](https://manual.cs50.io/2/sched_setscheduler) - set and get scheduling policy/parameters - [sched\_yield](https://manual.cs50.io/2/sched_yield) - yield the processor - [setns](https://manual.cs50.io/2/setns) - reassociate thread with a namespace - [unshare](https://manual.cs50.io/2/unshare) - disassociate parts of the process execution context # [search.h](https://manual.cs50.io/#search.h) - [hcreate](https://manual.cs50.io/3/hcreate) - hash table management - [hcreate\_r](https://manual.cs50.io/3/hcreate_r) - hash table management - [hdestroy](https://manual.cs50.io/3/hdestroy) - hash table management - [hdestroy\_r](https://manual.cs50.io/3/hdestroy_r) - hash table management - [hsearch](https://manual.cs50.io/3/hsearch) - hash table management - [hsearch\_r](https://manual.cs50.io/3/hsearch_r) - hash table management - [insque](https://manual.cs50.io/3/insque) - insert/remove an item from a queue - [lfind](https://manual.cs50.io/3/lfind) - linear search of an array - [lsearch](https://manual.cs50.io/3/lsearch) - linear search of an array - [remque](https://manual.cs50.io/3/remque) - insert/remove an item from a queue - [tdelete](https://manual.cs50.io/3/tdelete) - manage a binary search tree - [tdestroy](https://manual.cs50.io/3/tdestroy) - manage a binary search tree - [tfind](https://manual.cs50.io/3/tfind) - manage a binary search tree - [tsearch](https://manual.cs50.io/3/tsearch) - manage a binary search tree - [twalk](https://manual.cs50.io/3/twalk) - manage a binary search tree - [twalk\_r](https://manual.cs50.io/3/twalk_r) - manage a binary search tree # [semaphore.h](https://manual.cs50.io/#semaphore.h) - [sem\_close](https://manual.cs50.io/3/sem_close) - close a named semaphore - [sem\_destroy](https://manual.cs50.io/3/sem_destroy) - destroy an unnamed semaphore - [sem\_getvalue](https://manual.cs50.io/3/sem_getvalue) - get the value of a semaphore - [sem\_init](https://manual.cs50.io/3/sem_init) - initialize an unnamed semaphore - [sem\_open](https://manual.cs50.io/3/sem_open) - initialize and open a named semaphore - [sem\_post](https://manual.cs50.io/3/sem_post) - unlock a semaphore - [sem\_timedwait](https://manual.cs50.io/3/sem_timedwait) - lock a semaphore - [sem\_trywait](https://manual.cs50.io/3/sem_trywait) - lock a semaphore - [sem\_unlink](https://manual.cs50.io/3/sem_unlink) - remove a named semaphore - [sem\_wait](https://manual.cs50.io/3/sem_wait) - lock a semaphore # [setjmp.h](https://manual.cs50.io/#setjmp.h) - [longjmp](https://manual.cs50.io/3/longjmp) - performing a nonlocal goto - [setjmp](https://manual.cs50.io/3/setjmp) - performing a nonlocal goto - [siglongjmp](https://manual.cs50.io/3/siglongjmp) - performing a nonlocal goto - [sigsetjmp](https://manual.cs50.io/3/sigsetjmp) - performing a nonlocal goto # [signal.h](https://manual.cs50.io/#signal.h) - [bsd\_signal](https://manual.cs50.io/3/bsd_signal) - signal handling with BSD semantics - [gsignal](https://manual.cs50.io/3/gsignal) - software signal facility - [kill](https://manual.cs50.io/2/kill) - send signal to a process - [killpg](https://manual.cs50.io/3/killpg) - send signal to a process group - [psiginfo](https://manual.cs50.io/3/psiginfo) - print signal description - [psignal](https://manual.cs50.io/3/psignal) - print signal description - [pthread\_kill](https://manual.cs50.io/3/pthread_kill) - send a signal to a thread - [pthread\_sigmask](https://manual.cs50.io/3/pthread_sigmask) - examine and change mask of blocked signals - [pthread\_sigqueue](https://manual.cs50.io/3/pthread_sigqueue) - queue a signal and data to a thread - [raise](https://manual.cs50.io/3/raise) - send a signal to the caller - [rt\_sigaction](https://manual.cs50.io/2/rt_sigaction) - examine and change a signal action - [rt\_sigpending](https://manual.cs50.io/2/rt_sigpending) - examine pending signals - [rt\_sigprocmask](https://manual.cs50.io/2/rt_sigprocmask) - examine and change blocked signals - [rt\_sigsuspend](https://manual.cs50.io/2/rt_sigsuspend) - wait for a signal - [rt\_sigtimedwait](https://manual.cs50.io/2/rt_sigtimedwait) - synchronously wait for queued signals - [sigaction](https://manual.cs50.io/2/sigaction) - examine and change a signal action - [sigaddset](https://manual.cs50.io/3/sigaddset) - POSIX signal set operations - [sigaltstack](https://manual.cs50.io/2/sigaltstack) - set and/or get signal stack context - [sigandset](https://manual.cs50.io/3/sigandset) - POSIX signal set operations - [sigblock](https://manual.cs50.io/3/sigblock) - BSD signal API - [sigdelset](https://manual.cs50.io/3/sigdelset) - POSIX signal set operations - [sigemptyset](https://manual.cs50.io/3/sigemptyset) - POSIX signal set operations - [sigfillset](https://manual.cs50.io/3/sigfillset) - POSIX signal set operations - [siggetmask](https://manual.cs50.io/3/siggetmask) - BSD signal API - [sighold](https://manual.cs50.io/3/sighold) - System V signal API - [sigignore](https://manual.cs50.io/3/sigignore) - System V signal API - [siginterrupt](https://manual.cs50.io/3/siginterrupt) - allow signals to interrupt system calls - [sigisemptyset](https://manual.cs50.io/3/sigisemptyset) - POSIX signal set operations - [sigismember](https://manual.cs50.io/3/sigismember) - POSIX signal set operations - [sigmask](https://manual.cs50.io/3/sigmask) - BSD signal API - [signal](https://manual.cs50.io/2/signal) - ANSI C signal handling - [sigorset](https://manual.cs50.io/3/sigorset) - POSIX signal set operations - [sigpause](https://manual.cs50.io/3/sigpause) - atomically release blocked signals and wait for interrupt - [sigpending](https://manual.cs50.io/2/sigpending) - examine pending signals - [sigprocmask](https://manual.cs50.io/2/sigprocmask) - examine and change blocked signals - [sigqueue](https://manual.cs50.io/3/sigqueue) - queue a signal and data to a process - [sigrelse](https://manual.cs50.io/3/sigrelse) - System V signal API - [sigset](https://manual.cs50.io/3/sigset) - System V signal API - [sigsetmask](https://manual.cs50.io/3/sigsetmask) - BSD signal API - [sigsetops](https://manual.cs50.io/3/sigsetops) - POSIX signal set operations - [sigstack](https://manual.cs50.io/3/sigstack) - set and/or get signal stack context - [sigsuspend](https://manual.cs50.io/2/sigsuspend) - wait for a signal - [sigtimedwait](https://manual.cs50.io/2/sigtimedwait) - synchronously wait for queued signals - [sigvec](https://manual.cs50.io/3/sigvec) - BSD signal API - [sigwait](https://manual.cs50.io/3/sigwait) - wait for a signal - [sigwaitinfo](https://manual.cs50.io/2/sigwaitinfo) - synchronously wait for queued signals - [ssignal](https://manual.cs50.io/3/ssignal) - software signal facility - [sysv\_signal](https://manual.cs50.io/3/sysv_signal) - signal handling with System V semantics # [spawn.h](https://manual.cs50.io/#spawn.h) - [posix\_spawn](https://manual.cs50.io/3/posix_spawn) - spawn a process - [posix\_spawnp](https://manual.cs50.io/3/posix_spawnp) - spawn a process # [stdarg.h](https://manual.cs50.io/#stdarg.h) - [stdarg](https://manual.cs50.io/3/stdarg) - variable argument lists - [va\_arg](https://manual.cs50.io/3/va_arg) - variable argument lists - [va\_copy](https://manual.cs50.io/3/va_copy) - variable argument lists - [va\_end](https://manual.cs50.io/3/va_end) - variable argument lists - [va\_start](https://manual.cs50.io/3/va_start) - variable argument lists # [stddef.h](https://manual.cs50.io/#stddef.h) - [offsetof](https://manual.cs50.io/3/offsetof) - offset of a structure member - [wcstoimax](https://manual.cs50.io/3/wcstoimax) - convert wide-character string to integer - [wcstoumax](https://manual.cs50.io/3/wcstoumax) - convert wide-character string to integer # [stdio.h](https://manual.cs50.io/#stdio.h) - [\_\_fbufsize](https://manual.cs50.io/3/__fbufsize) - interfaces to stdio FILE structure - [\_\_flbf](https://manual.cs50.io/3/__flbf) - interfaces to stdio FILE structure - [\_\_fpending](https://manual.cs50.io/3/__fpending) - interfaces to stdio FILE structure - [\_\_fpurge](https://manual.cs50.io/3/__fpurge) - purge a stream - [\_\_freadable](https://manual.cs50.io/3/__freadable) - interfaces to stdio FILE structure - [\_\_freading](https://manual.cs50.io/3/__freading) - interfaces to stdio FILE structure - [\_\_fsetlocking](https://manual.cs50.io/3/__fsetlocking) - interfaces to stdio FILE structure - [\_\_fwritable](https://manual.cs50.io/3/__fwritable) - interfaces to stdio FILE structure - [\_\_fwriting](https://manual.cs50.io/3/__fwriting) - interfaces to stdio FILE structure - [\_flushlbf](https://manual.cs50.io/3/_flushlbf) - interfaces to stdio FILE structure - [addmntent](https://manual.cs50.io/3/addmntent) - get filesystem descriptor file entry - [asprintf](https://manual.cs50.io/3/asprintf) - print to allocated string - [clearerr](https://manual.cs50.io/3/clearerr) - check and reset stream status - [clearerr\_unlocked](https://manual.cs50.io/3/clearerr_unlocked) - nonlocking stdio functions - [ctermid](https://manual.cs50.io/3/ctermid) - get controlling terminal name - [dprintf](https://manual.cs50.io/3/dprintf) - formatted output conversion - [endmntent](https://manual.cs50.io/3/endmntent) - get filesystem descriptor file entry - [fclose](https://manual.cs50.io/3/fclose) - close a stream close a file - [fcloseall](https://manual.cs50.io/3/fcloseall) - close all open streams - [fdopen](https://manual.cs50.io/3/fdopen) - stream open functions - [feof](https://manual.cs50.io/3/feof) - check and reset stream status - [feof\_unlocked](https://manual.cs50.io/3/feof_unlocked) - nonlocking stdio functions - [ferror](https://manual.cs50.io/3/ferror) - check and reset stream status - [ferror\_unlocked](https://manual.cs50.io/3/ferror_unlocked) - nonlocking stdio functions - [fflush](https://manual.cs50.io/3/fflush) - flush a stream - [fflush\_unlocked](https://manual.cs50.io/3/fflush_unlocked) - nonlocking stdio functions - [fgetc](https://manual.cs50.io/3/fgetc) - input of characters and strings - [fgetc\_unlocked](https://manual.cs50.io/3/fgetc_unlocked) - nonlocking stdio functions - [fgetgrent](https://manual.cs50.io/3/fgetgrent) - get group file entry - [fgetpos](https://manual.cs50.io/3/fgetpos) - reposition a stream - [fgetpwent](https://manual.cs50.io/3/fgetpwent) - get password file entry - [fgets](https://manual.cs50.io/3/fgets) - input of characters and strings - [fgets\_unlocked](https://manual.cs50.io/3/fgets_unlocked) - nonlocking stdio functions - [fgetwc](https://manual.cs50.io/3/fgetwc) - read a wide character from a FILE stream - [fgetwc\_unlocked](https://manual.cs50.io/3/fgetwc_unlocked) - nonlocking stdio functions - [fgetws\_unlocked](https://manual.cs50.io/3/fgetws_unlocked) - nonlocking stdio functions - [fileno](https://manual.cs50.io/3/fileno) - obtain file descriptor of a stdio stream - [fileno\_unlocked](https://manual.cs50.io/3/fileno_unlocked) - nonlocking stdio functions - [flockfile](https://manual.cs50.io/3/flockfile) - lock FILE for stdio - [fmemopen](https://manual.cs50.io/3/fmemopen) - open memory as stream - [fopen](https://manual.cs50.io/3/fopen) - stream open functions open a file - [fopencookie](https://manual.cs50.io/3/fopencookie) - open a custom stream - [fprintf](https://manual.cs50.io/3/fprintf) - formatted output conversion print to a file - [fpurge](https://manual.cs50.io/3/fpurge) - purge a stream - [fputc](https://manual.cs50.io/3/fputc) - output of characters and strings - [fputc\_unlocked](https://manual.cs50.io/3/fputc_unlocked) - nonlocking stdio functions - [fputs](https://manual.cs50.io/3/fputs) - output of characters and strings - [fputs\_unlocked](https://manual.cs50.io/3/fputs_unlocked) - nonlocking stdio functions - [fputwc](https://manual.cs50.io/3/fputwc) - write a wide character to a FILE stream - [fputwc\_unlocked](https://manual.cs50.io/3/fputwc_unlocked) - nonlocking stdio functions - [fputws\_unlocked](https://manual.cs50.io/3/fputws_unlocked) - nonlocking stdio functions - [fread](https://manual.cs50.io/3/fread) - binary stream input/output read bytes from a file - [fread\_unlocked](https://manual.cs50.io/3/fread_unlocked) - nonlocking stdio functions - [freopen](https://manual.cs50.io/3/freopen) - stream open functions - [fscanf](https://manual.cs50.io/3/fscanf) - input FILE format conversion get input from a file - [fseek](https://manual.cs50.io/3/fseek) - reposition a stream - [fseeko](https://manual.cs50.io/3/fseeko) - seek to or report file position - [fsetpos](https://manual.cs50.io/3/fsetpos) - reposition a stream - [ftell](https://manual.cs50.io/3/ftell) - reposition a stream - [ftello](https://manual.cs50.io/3/ftello) - seek to or report file position - [ftrylockfile](https://manual.cs50.io/3/ftrylockfile) - lock FILE for stdio - [funlockfile](https://manual.cs50.io/3/funlockfile) - lock FILE for stdio - [fwprintf](https://manual.cs50.io/3/fwprintf) - formatted wide-character output conversion - [fwrite](https://manual.cs50.io/3/fwrite) - binary stream input/output write bytes to a file - [fwrite\_unlocked](https://manual.cs50.io/3/fwrite_unlocked) - nonlocking stdio functions - [getc](https://manual.cs50.io/3/getc) - input of characters and strings - [getc\_unlocked](https://manual.cs50.io/3/getc_unlocked) - nonlocking stdio functions - [getchar](https://manual.cs50.io/3/getchar) - input of characters and strings - [getchar\_unlocked](https://manual.cs50.io/3/getchar_unlocked) - nonlocking stdio functions - [getdelim](https://manual.cs50.io/3/getdelim) - delimited string input - [getline](https://manual.cs50.io/3/getline) - delimited string input - [getmntent](https://manual.cs50.io/3/getmntent) - get filesystem descriptor file entry - [getmntent\_r](https://manual.cs50.io/3/getmntent_r) - get filesystem descriptor file entry - [gets](https://manual.cs50.io/3/gets) - get a string from standard input (DEPRECATED) - [getw](https://manual.cs50.io/3/getw) - input and output of words (ints) - [getwc](https://manual.cs50.io/3/getwc) - read a wide character from a FILE stream - [getwc\_unlocked](https://manual.cs50.io/3/getwc_unlocked) - nonlocking stdio functions - [getwchar\_unlocked](https://manual.cs50.io/3/getwchar_unlocked) - nonlocking stdio functions - [hasmntopt](https://manual.cs50.io/3/hasmntopt) - get filesystem descriptor file entry - [open\_memstream](https://manual.cs50.io/3/open_memstream) - open a dynamic memory buffer stream - [open\_wmemstream](https://manual.cs50.io/3/open_wmemstream) - open a dynamic memory buffer stream - [pclose](https://manual.cs50.io/3/pclose) - pipe stream to or from a process - [perror](https://manual.cs50.io/3/perror) - print a system error message - [popen](https://manual.cs50.io/3/popen) - pipe stream to or from a process - [printf](https://manual.cs50.io/3/printf) - formatted output conversion print to the screen - [putc](https://manual.cs50.io/3/putc) - output of characters and strings - [putc\_unlocked](https://manual.cs50.io/3/putc_unlocked) - nonlocking stdio functions - [putchar](https://manual.cs50.io/3/putchar) - output of characters and strings - [putchar\_unlocked](https://manual.cs50.io/3/putchar_unlocked) - nonlocking stdio functions - [putpwent](https://manual.cs50.io/3/putpwent) - write a password file entry - [puts](https://manual.cs50.io/3/puts) - output of characters and strings - [putw](https://manual.cs50.io/3/putw) - input and output of words (ints) - [putwc](https://manual.cs50.io/3/putwc) - write a wide character to a FILE stream - [putwc\_unlocked](https://manual.cs50.io/3/putwc_unlocked) - nonlocking stdio functions - [putwchar\_unlocked](https://manual.cs50.io/3/putwchar_unlocked) - nonlocking stdio functions - [remove](https://manual.cs50.io/3/remove) - remove a file or directory - [rename](https://manual.cs50.io/2/rename) - change the name or location of a file - [renameat](https://manual.cs50.io/2/renameat) - change the name or location of a file - [renameat2](https://manual.cs50.io/2/renameat2) - change the name or location of a file - [rewind](https://manual.cs50.io/3/rewind) - reposition a stream - [scanf](https://manual.cs50.io/3/scanf) - input FILE format conversion get input from a user - [setbuf](https://manual.cs50.io/3/setbuf) - stream buffering operations - [setbuffer](https://manual.cs50.io/3/setbuffer) - stream buffering operations - [setlinebuf](https://manual.cs50.io/3/setlinebuf) - stream buffering operations - [setmntent](https://manual.cs50.io/3/setmntent) - get filesystem descriptor file entry - [setvbuf](https://manual.cs50.io/3/setvbuf) - stream buffering operations - [snprintf](https://manual.cs50.io/3/snprintf) - formatted output conversion - [sprintf](https://manual.cs50.io/3/sprintf) - formatted output conversion print to a string - [sscanf](https://manual.cs50.io/3/sscanf) - input string format conversion - [stderr](https://manual.cs50.io/3/stderr) - standard I/O streams - [stdin](https://manual.cs50.io/3/stdin) - standard I/O streams - [stdio](https://manual.cs50.io/3/stdio) - standard input/output library functions - [stdio\_ext](https://manual.cs50.io/3/stdio_ext) - interfaces to stdio FILE structure - [stdout](https://manual.cs50.io/3/stdout) - standard I/O streams - [swprintf](https://manual.cs50.io/3/swprintf) - formatted wide-character output conversion - [sys\_errlist](https://manual.cs50.io/3/sys_errlist) - print a system error message - [sys\_nerr](https://manual.cs50.io/3/sys_nerr) - print a system error message - [tempnam](https://manual.cs50.io/3/tempnam) - create a name for a temporary file - [tmpfile](https://manual.cs50.io/3/tmpfile) - create a temporary file - [tmpnam](https://manual.cs50.io/3/tmpnam) - create a name for a temporary file - [tmpnam\_r](https://manual.cs50.io/3/tmpnam_r) - create a name for a temporary file - [ungetc](https://manual.cs50.io/3/ungetc) - input of characters and strings - [unlocked\_stdio](https://manual.cs50.io/3/unlocked_stdio) - nonlocking stdio functions - [vasprintf](https://manual.cs50.io/3/vasprintf) - print to allocated string - [vdprintf](https://manual.cs50.io/3/vdprintf) - formatted output conversion - [vfprintf](https://manual.cs50.io/3/vfprintf) - formatted output conversion - [vfscanf](https://manual.cs50.io/3/vfscanf) - input FILE format conversion - [vfwprintf](https://manual.cs50.io/3/vfwprintf) - formatted wide-character output conversion - [vprintf](https://manual.cs50.io/3/vprintf) - formatted output conversion - [vscanf](https://manual.cs50.io/3/vscanf) - input FILE format conversion - [vsnprintf](https://manual.cs50.io/3/vsnprintf) - formatted output conversion - [vsprintf](https://manual.cs50.io/3/vsprintf) - formatted output conversion - [vsscanf](https://manual.cs50.io/3/vsscanf) - input string format conversion - [vswprintf](https://manual.cs50.io/3/vswprintf) - formatted wide-character output conversion - [vwprintf](https://manual.cs50.io/3/vwprintf) - formatted wide-character output conversion - [wprintf](https://manual.cs50.io/3/wprintf) - formatted wide-character output conversion # [stdlib.h](https://manual.cs50.io/#stdlib.h) - [a64l](https://manual.cs50.io/3/a64l) - convert between long and base-64 - [abort](https://manual.cs50.io/3/abort) - cause abnormal process termination - [abs](https://manual.cs50.io/3/abs) - compute the absolute value of an integer - [aligned\_alloc](https://manual.cs50.io/3/aligned_alloc) - allocate aligned memory - [arc4random](https://manual.cs50.io/3/arc4random) - cryptographically-secure pseudorandom number generator - [arc4random\_buf](https://manual.cs50.io/3/arc4random_buf) - cryptographically-secure pseudorandom number generator - [arc4random\_uniform](https://manual.cs50.io/3/arc4random_uniform) - cryptographically-secure pseudorandom number generator - [atexit](https://manual.cs50.io/3/atexit) - register a function to be called at normal process ter... - [atof](https://manual.cs50.io/3/atof) - convert a string to a double convert a `string` to a `float` - [atoi](https://manual.cs50.io/3/atoi) - convert a string to an integer convert a `string` to an `int` - [atol](https://manual.cs50.io/3/atol) - convert a string to an integer convert a `string` to a `long` - [atoll](https://manual.cs50.io/3/atoll) - convert a string to an integer - [atoq](https://manual.cs50.io/3/atoq) - convert a string to an integer - [bsearch](https://manual.cs50.io/3/bsearch) - binary search of a sorted array - [calloc](https://manual.cs50.io/3/calloc) - allocate and free dynamic memory - [canonicalize\_file\_name](https://manual.cs50.io/3/canonicalize_file_name) - return the canonicalized absolute pathname - [cfree](https://manual.cs50.io/3/cfree) - free allocated memory - [clearenv](https://manual.cs50.io/3/clearenv) - clear the environment - [div](https://manual.cs50.io/3/div) - compute quotient and remainder of an integer division - [drand48](https://manual.cs50.io/3/drand48) - generate uniformly distributed pseudo-random numbers - [drand48\_r](https://manual.cs50.io/3/drand48_r) - generate uniformly distributed pseudo-random numbers r... - [ecvt](https://manual.cs50.io/3/ecvt) - convert a floating-point number to a string - [ecvt\_r](https://manual.cs50.io/3/ecvt_r) - convert a floating-point number to a string - [erand48](https://manual.cs50.io/3/erand48) - generate uniformly distributed pseudo-random numbers - [erand48\_r](https://manual.cs50.io/3/erand48_r) - generate uniformly distributed pseudo-random numbers r... - [exit](https://manual.cs50.io/3/exit) - cause normal process termination - [fcvt](https://manual.cs50.io/3/fcvt) - convert a floating-point number to a string - [fcvt\_r](https://manual.cs50.io/3/fcvt_r) - convert a floating-point number to a string - [free](https://manual.cs50.io/3/free) - allocate and free dynamic memory free dynamically allocated memory - [gcvt](https://manual.cs50.io/3/gcvt) - convert a floating-point number to a string - [getenv](https://manual.cs50.io/3/getenv) - get an environment variable - [getloadavg](https://manual.cs50.io/3/getloadavg) - get system load averages - [getpt](https://manual.cs50.io/3/getpt) - open a new pseudoterminal master - [getsubopt](https://manual.cs50.io/3/getsubopt) - parse suboption arguments from a string - [grantpt](https://manual.cs50.io/3/grantpt) - grant access to the slave pseudoterminal - [imaxabs](https://manual.cs50.io/3/imaxabs) - compute the absolute value of an integer - [imaxdiv](https://manual.cs50.io/3/imaxdiv) - compute quotient and remainder of an integer division - [initstate](https://manual.cs50.io/3/initstate) - random number generator - [initstate\_r](https://manual.cs50.io/3/initstate_r) - reentrant random number generator - [jrand48](https://manual.cs50.io/3/jrand48) - generate uniformly distributed pseudo-random numbers - [jrand48\_r](https://manual.cs50.io/3/jrand48_r) - generate uniformly distributed pseudo-random numbers r... - [l64a](https://manual.cs50.io/3/l64a) - convert between long and base-64 - [labs](https://manual.cs50.io/3/labs) - compute the absolute value of an integer - [lcong48](https://manual.cs50.io/3/lcong48) - generate uniformly distributed pseudo-random numbers - [lcong48\_r](https://manual.cs50.io/3/lcong48_r) - generate uniformly distributed pseudo-random numbers r... - [ldiv](https://manual.cs50.io/3/ldiv) - compute quotient and remainder of an integer division - [llabs](https://manual.cs50.io/3/llabs) - compute the absolute value of an integer - [lldiv](https://manual.cs50.io/3/lldiv) - compute quotient and remainder of an integer division - [lrand48](https://manual.cs50.io/3/lrand48) - generate uniformly distributed pseudo-random numbers - [lrand48\_r](https://manual.cs50.io/3/lrand48_r) - generate uniformly distributed pseudo-random numbers r... - [malloc](https://manual.cs50.io/3/malloc) - allocate and free dynamic memory allocate memory dynamically - [MB\_CUR\_MAX](https://manual.cs50.io/3/MB_CUR_MAX) - maximum length of a multibyte character in the current... - [mblen](https://manual.cs50.io/3/mblen) - determine number of bytes in next multibyte character - [mbstowcs](https://manual.cs50.io/3/mbstowcs) - convert a multibyte string to a wide-character string - [mbtowc](https://manual.cs50.io/3/mbtowc) - convert a multibyte sequence to a wide character - [memalign](https://manual.cs50.io/3/memalign) - allocate aligned memory - [mkdtemp](https://manual.cs50.io/3/mkdtemp) - create a unique temporary directory - [mkostemp](https://manual.cs50.io/3/mkostemp) - create a unique temporary file - [mkostemps](https://manual.cs50.io/3/mkostemps) - create a unique temporary file - [mkstemp](https://manual.cs50.io/3/mkstemp) - create a unique temporary file - [mkstemps](https://manual.cs50.io/3/mkstemps) - create a unique temporary file - [mktemp](https://manual.cs50.io/3/mktemp) - make a unique temporary filename - [mrand48](https://manual.cs50.io/3/mrand48) - generate uniformly distributed pseudo-random numbers - [mrand48\_r](https://manual.cs50.io/3/mrand48_r) - generate uniformly distributed pseudo-random numbers r... - [nrand48](https://manual.cs50.io/3/nrand48) - generate uniformly distributed pseudo-random numbers - [nrand48\_r](https://manual.cs50.io/3/nrand48_r) - generate uniformly distributed pseudo-random numbers r... - [on\_exit](https://manual.cs50.io/3/on_exit) - register a function to be called at normal process ter... - [posix\_memalign](https://manual.cs50.io/3/posix_memalign) - allocate aligned memory - [posix\_openpt](https://manual.cs50.io/3/posix_openpt) - open a pseudoterminal device - [ptsname](https://manual.cs50.io/3/ptsname) - get the name of the slave pseudoterminal - [ptsname\_r](https://manual.cs50.io/3/ptsname_r) - get the name of the slave pseudoterminal - [putenv](https://manual.cs50.io/3/putenv) - change or add an environment variable - [pvalloc](https://manual.cs50.io/3/pvalloc) - allocate aligned memory - [qecvt](https://manual.cs50.io/3/qecvt) - convert a floating-point number to a string - [qecvt\_r](https://manual.cs50.io/3/qecvt_r) - convert a floating-point number to a string - [qfcvt](https://manual.cs50.io/3/qfcvt) - convert a floating-point number to a string - [qfcvt\_r](https://manual.cs50.io/3/qfcvt_r) - convert a floating-point number to a string - [qgcvt](https://manual.cs50.io/3/qgcvt) - convert a floating-point number to a string - [qsort](https://manual.cs50.io/3/qsort) - sort an array - [qsort\_r](https://manual.cs50.io/3/qsort_r) - sort an array - [rand](https://manual.cs50.io/3/rand) - pseudo-random number generator - [rand\_r](https://manual.cs50.io/3/rand_r) - pseudo-random number generator - [random](https://manual.cs50.io/3/random) - random number generator generate a pseudorandom number - [random\_r](https://manual.cs50.io/3/random_r) - reentrant random number generator - [realloc](https://manual.cs50.io/3/realloc) - allocate and free dynamic memory reallocate memory dynamically - [reallocarray](https://manual.cs50.io/3/reallocarray) - allocate and free dynamic memory - [rpmatch](https://manual.cs50.io/3/rpmatch) - determine if the answer to a question is affirmative o... - [secure\_getenv](https://manual.cs50.io/3/secure_getenv) - get an environment variable - [seed48](https://manual.cs50.io/3/seed48) - generate uniformly distributed pseudo-random numbers - [seed48\_r](https://manual.cs50.io/3/seed48_r) - generate uniformly distributed pseudo-random numbers r... - [setenv](https://manual.cs50.io/3/setenv) - change or add an environment variable - [setstate](https://manual.cs50.io/3/setstate) - random number generator - [setstate\_r](https://manual.cs50.io/3/setstate_r) - reentrant random number generator - [srand](https://manual.cs50.io/3/srand) - pseudo-random number generator - [srand48](https://manual.cs50.io/3/srand48) - generate uniformly distributed pseudo-random numbers - [srand48\_r](https://manual.cs50.io/3/srand48_r) - generate uniformly distributed pseudo-random numbers r... - [srandom](https://manual.cs50.io/3/srandom) - random number generator seed pseudorandom number generation - [srandom\_r](https://manual.cs50.io/3/srandom_r) - reentrant random number generator - [strfromd](https://manual.cs50.io/3/strfromd) - convert a floating-point value into a string - [strfromf](https://manual.cs50.io/3/strfromf) - convert a floating-point value into a string - [strfroml](https://manual.cs50.io/3/strfroml) - convert a floating-point value into a string - [strtod](https://manual.cs50.io/3/strtod) - convert ASCII string to floating-point number - [strtof](https://manual.cs50.io/3/strtof) - convert ASCII string to floating-point number - [strtol](https://manual.cs50.io/3/strtol) - convert a string to a long integer - [strtold](https://manual.cs50.io/3/strtold) - convert ASCII string to floating-point number - [strtoll](https://manual.cs50.io/3/strtoll) - convert a string to a long integer - [strtoq](https://manual.cs50.io/3/strtoq) - convert a string to a long integer - [strtoul](https://manual.cs50.io/3/strtoul) - convert a string to an unsigned long integer - [strtoull](https://manual.cs50.io/3/strtoull) - convert a string to an unsigned long integer - [strtouq](https://manual.cs50.io/3/strtouq) - convert a string to an unsigned long integer - [system](https://manual.cs50.io/3/system) - execute a shell command - [unlockpt](https://manual.cs50.io/3/unlockpt) - unlock a pseudoterminal master/slave pair - [unsetenv](https://manual.cs50.io/3/unsetenv) - change or add an environment variable - [valloc](https://manual.cs50.io/3/valloc) - allocate aligned memory - [wcstombs](https://manual.cs50.io/3/wcstombs) - convert a wide-character string to a multibyte string - [wctomb](https://manual.cs50.io/3/wctomb) - convert a wide character to a multibyte sequence # [string.h](https://manual.cs50.io/#string.h) - [bstring](https://manual.cs50.io/3/bstring) - byte string operations - [memccpy](https://manual.cs50.io/3/memccpy) - copy memory area - [memchr](https://manual.cs50.io/3/memchr) - scan memory for a character - [memcmp](https://manual.cs50.io/3/memcmp) - compare memory areas - [memcpy](https://manual.cs50.io/3/memcpy) - copy memory area - [memfrob](https://manual.cs50.io/3/memfrob) - frobnicate (obfuscate) a memory area - [memmem](https://manual.cs50.io/3/memmem) - locate a substring - [memmove](https://manual.cs50.io/3/memmove) - copy memory area - [mempcpy](https://manual.cs50.io/3/mempcpy) - copy memory area - [memrchr](https://manual.cs50.io/3/memrchr) - scan memory for a character - [memset](https://manual.cs50.io/3/memset) - fill memory with a constant byte - [rawmemchr](https://manual.cs50.io/3/rawmemchr) - scan memory for a character - [sigabbrev\_np](https://manual.cs50.io/3/sigabbrev_np) - return string describing signal - [sigdescr\_np](https://manual.cs50.io/3/sigdescr_np) - return string describing signal - [stpcpy](https://manual.cs50.io/3/stpcpy) - copy or catenate a string - [stpncpy](https://manual.cs50.io/3/stpncpy) - fill a fixed-size buffer with non-null bytes from a st... - [strcasestr](https://manual.cs50.io/3/strcasestr) - locate a substring locate a substring - [strcat](https://manual.cs50.io/3/strcat) - copy or catenate a string - [strchr](https://manual.cs50.io/3/strchr) - locate character in string - [strchrnul](https://manual.cs50.io/3/strchrnul) - locate character in string - [strcmp](https://manual.cs50.io/3/strcmp) - compare two strings compare two strings - [strcoll](https://manual.cs50.io/3/strcoll) - compare two strings using the current locale - [strcpy](https://manual.cs50.io/3/strcpy) - copy or catenate a string copy a string - [strcspn](https://manual.cs50.io/3/strcspn) - get length of a prefix substring - [strdup](https://manual.cs50.io/3/strdup) - duplicate a string - [strdupa](https://manual.cs50.io/3/strdupa) - duplicate a string - [strerror](https://manual.cs50.io/3/strerror) - return string describing error number - [strerror\_l](https://manual.cs50.io/3/strerror_l) - return string describing error number - [strerror\_r](https://manual.cs50.io/3/strerror_r) - return string describing error number - [strerrordesc\_np](https://manual.cs50.io/3/strerrordesc_np) - return string describing error number - [strerrorname\_np](https://manual.cs50.io/3/strerrorname_np) - return string describing error number - [strfry](https://manual.cs50.io/3/strfry) - randomize a string - [strlen](https://manual.cs50.io/3/strlen) - calculate the length of a string calculate the length of a string - [strncat](https://manual.cs50.io/3/strncat) - append non-null bytes from a source array to a string,... - [strncmp](https://manual.cs50.io/3/strncmp) - compare two strings - [strncpy](https://manual.cs50.io/3/strncpy) - fill a fixed-size buffer with non-null bytes from a st... - [strndup](https://manual.cs50.io/3/strndup) - duplicate a string - [strndupa](https://manual.cs50.io/3/strndupa) - duplicate a string - [strnlen](https://manual.cs50.io/3/strnlen) - determine the length of a fixed-size string - [strpbrk](https://manual.cs50.io/3/strpbrk) - search a string for any of a set of bytes - [strrchr](https://manual.cs50.io/3/strrchr) - locate character in string - [strsep](https://manual.cs50.io/3/strsep) - extract token from string - [strsignal](https://manual.cs50.io/3/strsignal) - return string describing signal - [strspn](https://manual.cs50.io/3/strspn) - get length of a prefix substring - [strstr](https://manual.cs50.io/3/strstr) - locate a substring locate a substring - [strtok](https://manual.cs50.io/3/strtok) - extract tokens from strings - [strtok\_r](https://manual.cs50.io/3/strtok_r) - extract tokens from strings - [strverscmp](https://manual.cs50.io/3/strverscmp) - compare two version strings - [strxfrm](https://manual.cs50.io/3/strxfrm) - string transformation - [sys\_siglist](https://manual.cs50.io/3/sys_siglist) - return string describing signal - [wmempcpy](https://manual.cs50.io/3/wmempcpy) - copy memory area # [strings.h](https://manual.cs50.io/#strings.h) - [bcmp](https://manual.cs50.io/3/bcmp) - compare byte sequences - [bcopy](https://manual.cs50.io/3/bcopy) - copy byte sequence - [bzero](https://manual.cs50.io/3/bzero) - zero a byte string - [explicit\_bzero](https://manual.cs50.io/3/explicit_bzero) - zero a byte string - [ffs](https://manual.cs50.io/3/ffs) - find first bit set in a word - [ffsl](https://manual.cs50.io/3/ffsl) - find first bit set in a word - [ffsll](https://manual.cs50.io/3/ffsll) - find first bit set in a word - [index](https://manual.cs50.io/3/index) - locate character in string - [rindex](https://manual.cs50.io/3/rindex) - locate character in string - [strcasecmp](https://manual.cs50.io/3/strcasecmp) - compare two strings ignoring case compare two strings ignoring case - [string](https://manual.cs50.io/3/string) - string operations - [strncasecmp](https://manual.cs50.io/3/strncasecmp) - compare two strings ignoring case # [sys/ipc.h](https://manual.cs50.io/#sys/ipc.h) - [ftok](https://manual.cs50.io/3/ftok) - convert a pathname and a project identifier to a Syste... # [sys/mman.h](https://manual.cs50.io/#sys/mman.h) - [madvise](https://manual.cs50.io/2/madvise) - give advice about use of memory - [memfd\_create](https://manual.cs50.io/2/memfd_create) - create an anonymous file - [mincore](https://manual.cs50.io/2/mincore) - determine whether pages are resident in memory - [mlock](https://manual.cs50.io/2/mlock) - lock and unlock memory - [mlock2](https://manual.cs50.io/2/mlock2) - lock and unlock memory - [mlockall](https://manual.cs50.io/2/mlockall) - lock and unlock memory - [mmap](https://manual.cs50.io/2/mmap) - map or unmap files or devices into memory - [mmap64](https://manual.cs50.io/3/mmap64) - map or unmap files or devices into memory - [mprotect](https://manual.cs50.io/2/mprotect) - set protection on a region of memory - [mremap](https://manual.cs50.io/2/mremap) - remap a virtual memory address - [msync](https://manual.cs50.io/2/msync) - synchronize a file with a memory map - [munlock](https://manual.cs50.io/2/munlock) - lock and unlock memory - [munlockall](https://manual.cs50.io/2/munlockall) - lock and unlock memory - [munmap](https://manual.cs50.io/2/munmap) - map or unmap files or devices into memory - [pkey\_alloc](https://manual.cs50.io/2/pkey_alloc) - allocate or free a protection key - [pkey\_free](https://manual.cs50.io/2/pkey_free) - allocate or free a protection key - [pkey\_mprotect](https://manual.cs50.io/2/pkey_mprotect) - set protection on a region of memory - [posix\_madvise](https://manual.cs50.io/3/posix_madvise) - give advice about patterns of memory usage - [process\_madvise](https://manual.cs50.io/2/process_madvise) - give advice about use of memory to a process - [remap\_file\_pages](https://manual.cs50.io/2/remap_file_pages) - create a nonlinear file mapping - [shm\_open](https://manual.cs50.io/3/shm_open) - create/open or unlink POSIX shared memory objects - [shm\_unlink](https://manual.cs50.io/3/shm_unlink) - create/open or unlink POSIX shared memory objects # [sys/msg.h](https://manual.cs50.io/#sys/msg.h) - [msgctl](https://manual.cs50.io/2/msgctl) - System V message control operations - [msgget](https://manual.cs50.io/2/msgget) - get a System V message queue identifier - [msgop](https://manual.cs50.io/2/msgop) - System V message queue operations - [msgrcv](https://manual.cs50.io/2/msgrcv) - System V message queue operations - [msgsnd](https://manual.cs50.io/2/msgsnd) - System V message queue operations # [sys/resource.h](https://manual.cs50.io/#sys/resource.h) - [getpriority](https://manual.cs50.io/2/getpriority) - get/set program scheduling priority - [getrlimit](https://manual.cs50.io/2/getrlimit) - get/set resource limits - [getrusage](https://manual.cs50.io/2/getrusage) - get resource usage - [prlimit](https://manual.cs50.io/2/prlimit) - get/set resource limits - [prlimit64](https://manual.cs50.io/2/prlimit64) - get/set resource limits - [setpriority](https://manual.cs50.io/2/setpriority) - get/set program scheduling priority - [setrlimit](https://manual.cs50.io/2/setrlimit) - get/set resource limits - [ugetrlimit](https://manual.cs50.io/2/ugetrlimit) - get/set resource limits - [vlimit](https://manual.cs50.io/3/vlimit) - get/set resource limits - [vtimes](https://manual.cs50.io/3/vtimes) - get resource usage # [sys/select.h](https://manual.cs50.io/#sys/select.h) - [\_newselect](https://manual.cs50.io/2/_newselect) - synchronous I/O multiplexing - [FD\_CLR](https://manual.cs50.io/3/FD_CLR) - synchronous I/O multiplexing - [FD\_ISSET](https://manual.cs50.io/3/FD_ISSET) - synchronous I/O multiplexing - [FD\_SET](https://manual.cs50.io/3/FD_SET) - synchronous I/O multiplexing - [FD\_ZERO](https://manual.cs50.io/3/FD_ZERO) - synchronous I/O multiplexing - [pselect](https://manual.cs50.io/2/pselect) - synchronous I/O multiplexing - [pselect6](https://manual.cs50.io/2/pselect6) - synchronous I/O multiplexing - [select](https://manual.cs50.io/2/select) - synchronous I/O multiplexing # [sys/sem.h](https://manual.cs50.io/#sys/sem.h) - [semctl](https://manual.cs50.io/2/semctl) - System V semaphore control operations - [semget](https://manual.cs50.io/2/semget) - get a System V semaphore set identifier - [semop](https://manual.cs50.io/2/semop) - System V semaphore operations - [semtimedop](https://manual.cs50.io/2/semtimedop) - System V semaphore operations # [sys/shm.h](https://manual.cs50.io/#sys/shm.h) - [shmat](https://manual.cs50.io/2/shmat) - System V shared memory operations - [shmctl](https://manual.cs50.io/2/shmctl) - System V shared memory control - [shmdt](https://manual.cs50.io/2/shmdt) - System V shared memory operations - [shmget](https://manual.cs50.io/2/shmget) - allocates a System V shared memory segment - [shmop](https://manual.cs50.io/2/shmop) - System V shared memory operations # [sys/socket.h](https://manual.cs50.io/#sys/socket.h) - [accept](https://manual.cs50.io/2/accept) - accept a connection on a socket - [accept4](https://manual.cs50.io/2/accept4) - accept a connection on a socket - [address\_families](https://manual.cs50.io/7/address_families) - socket address families (domains) - [bind](https://manual.cs50.io/2/bind) - bind a name to a socket - [cmsg](https://manual.cs50.io/3/cmsg) - access ancillary data - [CMSG\_ALIGN](https://manual.cs50.io/3/CMSG_ALIGN) - access ancillary data - [CMSG\_DATA](https://manual.cs50.io/3/CMSG_DATA) - access ancillary data - [CMSG\_FIRSTHDR](https://manual.cs50.io/3/CMSG_FIRSTHDR) - access ancillary data - [CMSG\_LEN](https://manual.cs50.io/3/CMSG_LEN) - access ancillary data - [CMSG\_NXTHDR](https://manual.cs50.io/3/CMSG_NXTHDR) - access ancillary data - [CMSG\_SPACE](https://manual.cs50.io/3/CMSG_SPACE) - access ancillary data - [connect](https://manual.cs50.io/2/connect) - initiate a connection on a socket - [ddp](https://manual.cs50.io/7/ddp) - Linux AppleTalk protocol implementation - [getnameinfo](https://manual.cs50.io/3/getnameinfo) - address-to-name translation in protocol-independent ma... - [getpeername](https://manual.cs50.io/2/getpeername) - get name of connected peer socket - [getsockname](https://manual.cs50.io/2/getsockname) - get socket name - [getsockopt](https://manual.cs50.io/2/getsockopt) - get and set options on sockets - [inet](https://manual.cs50.io/3/inet) - Internet address manipulation routines - [inet\_addr](https://manual.cs50.io/3/inet_addr) - Internet address manipulation routines - [inet\_aton](https://manual.cs50.io/3/inet_aton) - Internet address manipulation routines - [inet\_lnaof](https://manual.cs50.io/3/inet_lnaof) - Internet address manipulation routines - [inet\_makeaddr](https://manual.cs50.io/3/inet_makeaddr) - Internet address manipulation routines - [inet\_netof](https://manual.cs50.io/3/inet_netof) - Internet address manipulation routines - [inet\_network](https://manual.cs50.io/3/inet_network) - Internet address manipulation routines - [inet\_ntoa](https://manual.cs50.io/3/inet_ntoa) - Internet address manipulation routines - [ip](https://manual.cs50.io/7/ip) - Linux IPv4 protocol implementation - [ipv6](https://manual.cs50.io/7/ipv6) - Linux IPv6 protocol implementation - [listen](https://manual.cs50.io/2/listen) - listen for connections on a socket - [packet](https://manual.cs50.io/7/packet) - packet interface on device level - [raw](https://manual.cs50.io/7/raw) - Linux IPv4 raw sockets - [recv](https://manual.cs50.io/2/recv) - receive a message from a socket - [recvfrom](https://manual.cs50.io/2/recvfrom) - receive a message from a socket - [recvmmsg](https://manual.cs50.io/2/recvmmsg) - receive multiple messages on a socket - [recvmsg](https://manual.cs50.io/2/recvmsg) - receive a message from a socket - [send](https://manual.cs50.io/2/send) - send a message on a socket - [sendmmsg](https://manual.cs50.io/2/sendmmsg) - send multiple messages on a socket - [sendmsg](https://manual.cs50.io/2/sendmsg) - send a message on a socket - [sendto](https://manual.cs50.io/2/sendto) - send a message on a socket - [setsockopt](https://manual.cs50.io/2/setsockopt) - get and set options on sockets - [shutdown](https://manual.cs50.io/2/shutdown) - shut down part of a full-duplex connection - [sock\_diag](https://manual.cs50.io/7/sock_diag) - obtaining information about sockets - [sockatmark](https://manual.cs50.io/3/sockatmark) - determine whether socket is at out-of-band mark - [socket](https://manual.cs50.io/2/socket) - create an endpoint for communication - [socket](https://manual.cs50.io/7/socket) - Linux socket interface - [socketpair](https://manual.cs50.io/2/socketpair) - create a pair of connected sockets - [tcp](https://manual.cs50.io/7/tcp) - TCP protocol - [udp](https://manual.cs50.io/7/udp) - User Datagram Protocol for IPv4 - [udplite](https://manual.cs50.io/7/udplite) - Lightweight User Datagram Protocol - [unix](https://manual.cs50.io/7/unix) - sockets for local interprocess communication - [vsock](https://manual.cs50.io/7/vsock) - Linux VSOCK address family - [x25](https://manual.cs50.io/7/x25) - ITU-T X.25 / ISO/IEC 8208 protocol interface # [sys/stat.h](https://manual.cs50.io/#sys/stat.h) - [chmod](https://manual.cs50.io/2/chmod) - change permissions of a file - [fchmod](https://manual.cs50.io/2/fchmod) - change permissions of a file - [fchmodat](https://manual.cs50.io/2/fchmodat) - change permissions of a file - [fstat](https://manual.cs50.io/2/fstat) - get file status - [fstat64](https://manual.cs50.io/2/fstat64) - get file status - [fstatat](https://manual.cs50.io/2/fstatat) - get file status - [fstatat64](https://manual.cs50.io/2/fstatat64) - get file status - [futimens](https://manual.cs50.io/3/futimens) - change file timestamps with nanosecond precision - [isfdtype](https://manual.cs50.io/3/isfdtype) - test file type of a file descriptor - [lstat](https://manual.cs50.io/2/lstat) - get file status - [lstat64](https://manual.cs50.io/2/lstat64) - get file status - [mkdir](https://manual.cs50.io/2/mkdir) - create a directory - [mkdirat](https://manual.cs50.io/2/mkdirat) - create a directory - [mknod](https://manual.cs50.io/2/mknod) - create a special or ordinary file - [mknodat](https://manual.cs50.io/2/mknodat) - create a special or ordinary file - [newfstatat](https://manual.cs50.io/2/newfstatat) - get file status - [oldfstat](https://manual.cs50.io/2/oldfstat) - get file status - [oldlstat](https://manual.cs50.io/2/oldlstat) - get file status - [oldstat](https://manual.cs50.io/2/oldstat) - get file status - [stat](https://manual.cs50.io/2/stat) - get file status - [stat64](https://manual.cs50.io/2/stat64) - get file status - [statx](https://manual.cs50.io/2/statx) - get file status (extended) - [umask](https://manual.cs50.io/2/umask) - set file mode creation mask - [utimensat](https://manual.cs50.io/2/utimensat) - change file timestamps with nanosecond precision # [sys/statvfs.h](https://manual.cs50.io/#sys/statvfs.h) - [fstatvfs](https://manual.cs50.io/3/fstatvfs) - get filesystem statistics - [statvfs](https://manual.cs50.io/3/statvfs) - get filesystem statistics # [sys/time.h](https://manual.cs50.io/#sys/time.h) - [adjtime](https://manual.cs50.io/3/adjtime) - correct the time to synchronize the system clock - [futimes](https://manual.cs50.io/3/futimes) - change file timestamps - [futimesat](https://manual.cs50.io/2/futimesat) - change timestamps of a file relative to a directory fi... - [getitimer](https://manual.cs50.io/2/getitimer) - get or set value of an interval timer - [gettimeofday](https://manual.cs50.io/2/gettimeofday) - get / set time - [lutimes](https://manual.cs50.io/3/lutimes) - change file timestamps - [setitimer](https://manual.cs50.io/2/setitimer) - get or set value of an interval timer - [settimeofday](https://manual.cs50.io/2/settimeofday) - get / set time - [timeradd](https://manual.cs50.io/3/timeradd) - timeval operations - [timerclear](https://manual.cs50.io/3/timerclear) - timeval operations - [timercmp](https://manual.cs50.io/3/timercmp) - timeval operations - [timerisset](https://manual.cs50.io/3/timerisset) - timeval operations - [timersub](https://manual.cs50.io/3/timersub) - timeval operations - [TIMESPEC\_TO\_TIMEVAL](https://manual.cs50.io/3/TIMESPEC_TO_TIMEVAL) - convert between time structures - [TIMEVAL\_TO\_TIMESPEC](https://manual.cs50.io/3/TIMEVAL_TO_TIMESPEC) - convert between time structures # [sys/times.h](https://manual.cs50.io/#sys/times.h) - [times](https://manual.cs50.io/2/times) - get process times # [sys/types.h](https://manual.cs50.io/#sys/types.h) - [bindresvport](https://manual.cs50.io/3/bindresvport) - bind a socket to a privileged IP port - [closedir](https://manual.cs50.io/3/closedir) - close a directory - [db](https://manual.cs50.io/3/db) - database access methods - [dbopen](https://manual.cs50.io/3/dbopen) - database access methods - [dirfd](https://manual.cs50.io/3/dirfd) - get directory stream file descriptor - [endgrent](https://manual.cs50.io/3/endgrent) - get group file entry - [endpwent](https://manual.cs50.io/3/endpwent) - get password file entry - [fdopendir](https://manual.cs50.io/3/fdopendir) - open a directory - [freeaddrinfo](https://manual.cs50.io/3/freeaddrinfo) - network address and service translation - [freehostent](https://manual.cs50.io/3/freehostent) - get network hostnames and addresses - [freeifaddrs](https://manual.cs50.io/3/freeifaddrs) - get interface addresses - [fts](https://manual.cs50.io/3/fts) - traverse a file hierarchy - [fts\_children](https://manual.cs50.io/3/fts_children) - traverse a file hierarchy - [fts\_close](https://manual.cs50.io/3/fts_close) - traverse a file hierarchy - [fts\_open](https://manual.cs50.io/3/fts_open) - traverse a file hierarchy - [fts\_read](https://manual.cs50.io/3/fts_read) - traverse a file hierarchy - [fts\_set](https://manual.cs50.io/3/fts_set) - traverse a file hierarchy - [gai\_strerror](https://manual.cs50.io/3/gai_strerror) - network address and service translation - [getaddrinfo](https://manual.cs50.io/3/getaddrinfo) - network address and service translation - [getgrent](https://manual.cs50.io/3/getgrent) - get group file entry - [getgrgid](https://manual.cs50.io/3/getgrgid) - get group file entry - [getgrgid\_r](https://manual.cs50.io/3/getgrgid_r) - get group file entry - [getgrnam](https://manual.cs50.io/3/getgrnam) - get group file entry - [getgrnam\_r](https://manual.cs50.io/3/getgrnam_r) - get group file entry - [getifaddrs](https://manual.cs50.io/3/getifaddrs) - get interface addresses - [getipnodebyaddr](https://manual.cs50.io/3/getipnodebyaddr) - get network hostnames and addresses - [getipnodebyname](https://manual.cs50.io/3/getipnodebyname) - get network hostnames and addresses - [getpw](https://manual.cs50.io/3/getpw) - reconstruct password line entry - [getpwent](https://manual.cs50.io/3/getpwent) - get password file entry - [getpwnam](https://manual.cs50.io/3/getpwnam) - get password file entry - [getpwnam\_r](https://manual.cs50.io/3/getpwnam_r) - get password file entry - [getpwuid](https://manual.cs50.io/3/getpwuid) - get password file entry - [getpwuid\_r](https://manual.cs50.io/3/getpwuid_r) - get password file entry - [initgroups](https://manual.cs50.io/3/initgroups) - initialize the supplementary group access list - [lseek64](https://manual.cs50.io/3/lseek64) - reposition 64-bit read/write file offset - [mkfifo](https://manual.cs50.io/3/mkfifo) - make a FIFO special file (a named pipe) - [mkfifoat](https://manual.cs50.io/3/mkfifoat) - make a FIFO special file (a named pipe) - [opendir](https://manual.cs50.io/3/opendir) - open a directory - [re\_comp](https://manual.cs50.io/3/re_comp) - BSD regex functions - [re\_exec](https://manual.cs50.io/3/re_exec) - BSD regex functions - [rewinddir](https://manual.cs50.io/3/rewinddir) - reset directory stream - [setgrent](https://manual.cs50.io/3/setgrent) - get group file entry - [setpwent](https://manual.cs50.io/3/setpwent) - get password file entry - [ustat](https://manual.cs50.io/2/ustat) - get filesystem statistics # [sys/uio.h](https://manual.cs50.io/#sys/uio.h) - [preadv](https://manual.cs50.io/2/preadv) - read or write data into multiple buffers - [preadv2](https://manual.cs50.io/2/preadv2) - read or write data into multiple buffers - [process\_vm\_readv](https://manual.cs50.io/2/process_vm_readv) - transfer data between process address spaces - [process\_vm\_writev](https://manual.cs50.io/2/process_vm_writev) - transfer data between process address spaces - [pwritev](https://manual.cs50.io/2/pwritev) - read or write data into multiple buffers - [pwritev2](https://manual.cs50.io/2/pwritev2) - read or write data into multiple buffers - [readv](https://manual.cs50.io/2/readv) - read or write data into multiple buffers - [writev](https://manual.cs50.io/2/writev) - read or write data into multiple buffers # [sys/utsname.h](https://manual.cs50.io/#sys/utsname.h) - [oldolduname](https://manual.cs50.io/2/oldolduname) - get name and information about current kernel - [olduname](https://manual.cs50.io/2/olduname) - get name and information about current kernel - [uname](https://manual.cs50.io/2/uname) - get name and information about current kernel # [sys/wait.h](https://manual.cs50.io/#sys/wait.h) - [wait](https://manual.cs50.io/2/wait) - wait for process to change state - [wait3](https://manual.cs50.io/2/wait3) - wait for process to change state, BSD style - [wait4](https://manual.cs50.io/2/wait4) - wait for process to change state, BSD style - [waitid](https://manual.cs50.io/2/waitid) - wait for process to change state - [waitpid](https://manual.cs50.io/2/waitpid) - wait for process to change state # [syslog.h](https://manual.cs50.io/#syslog.h) - [closelog](https://manual.cs50.io/3/closelog) - send messages to the system logger - [openlog](https://manual.cs50.io/3/openlog) - send messages to the system logger - [setlogmask](https://manual.cs50.io/3/setlogmask) - set log priority mask - [syslog](https://manual.cs50.io/3/syslog) - send messages to the system logger - [vsyslog](https://manual.cs50.io/3/vsyslog) - send messages to the system logger # [termios.h](https://manual.cs50.io/#termios.h) - [cfgetispeed](https://manual.cs50.io/3/cfgetispeed) - get and set terminal attributes, line control, get and... - [cfgetospeed](https://manual.cs50.io/3/cfgetospeed) - get and set terminal attributes, line control, get and... - [cfmakeraw](https://manual.cs50.io/3/cfmakeraw) - get and set terminal attributes, line control, get and... - [cfsetispeed](https://manual.cs50.io/3/cfsetispeed) - get and set terminal attributes, line control, get and... - [cfsetospeed](https://manual.cs50.io/3/cfsetospeed) - get and set terminal attributes, line control, get and... - [cfsetspeed](https://manual.cs50.io/3/cfsetspeed) - get and set terminal attributes, line control, get and... - [tcdrain](https://manual.cs50.io/3/tcdrain) - get and set terminal attributes, line control, get and... - [tcflow](https://manual.cs50.io/3/tcflow) - get and set terminal attributes, line control, get and... - [tcflush](https://manual.cs50.io/3/tcflush) - get and set terminal attributes, line control, get and... - [tcgetattr](https://manual.cs50.io/3/tcgetattr) - get and set terminal attributes, line control, get and... - [tcgetsid](https://manual.cs50.io/3/tcgetsid) - get session ID - [tcsendbreak](https://manual.cs50.io/3/tcsendbreak) - get and set terminal attributes, line control, get and... - [tcsetattr](https://manual.cs50.io/3/tcsetattr) - get and set terminal attributes, line control, get and... - [termios](https://manual.cs50.io/3/termios) - get and set terminal attributes, line control, get and... # [time.h](https://manual.cs50.io/#time.h) - [asctime](https://manual.cs50.io/3/asctime) - transform date and time to broken-down time or ASCII - [asctime\_r](https://manual.cs50.io/3/asctime_r) - transform date and time to broken-down time or ASCII - [clock](https://manual.cs50.io/3/clock) - determine processor time - [clock\_getcpuclockid](https://manual.cs50.io/3/clock_getcpuclockid) - obtain ID of a process CPU-time clock - [clock\_getres](https://manual.cs50.io/2/clock_getres) - clock and time functions - [clock\_gettime](https://manual.cs50.io/2/clock_gettime) - clock and time functions - [clock\_nanosleep](https://manual.cs50.io/2/clock_nanosleep) - high-resolution sleep with specifiable clock - [clock\_settime](https://manual.cs50.io/2/clock_settime) - clock and time functions - [ctime](https://manual.cs50.io/3/ctime) - transform date and time to broken-down time or ASCII - [ctime\_r](https://manual.cs50.io/3/ctime_r) - transform date and time to broken-down time or ASCII - [daylight](https://manual.cs50.io/3/daylight) - initialize time conversion information - [difftime](https://manual.cs50.io/3/difftime) - calculate time difference - [dysize](https://manual.cs50.io/3/dysize) - get number of days for a given year - [getdate](https://manual.cs50.io/3/getdate) - convert a date-plus-time string to broken-down time - [getdate\_err](https://manual.cs50.io/3/getdate_err) - convert a date-plus-time string to broken-down time - [getdate\_r](https://manual.cs50.io/3/getdate_r) - convert a date-plus-time string to broken-down time - [gmtime](https://manual.cs50.io/3/gmtime) - transform date and time to broken-down time or ASCII - [gmtime\_r](https://manual.cs50.io/3/gmtime_r) - transform date and time to broken-down time or ASCII - [localtime](https://manual.cs50.io/3/localtime) - transform date and time to broken-down time or ASCII - [localtime\_r](https://manual.cs50.io/3/localtime_r) - transform date and time to broken-down time or ASCII - [mktime](https://manual.cs50.io/3/mktime) - transform date and time to broken-down time or ASCII - [nanosleep](https://manual.cs50.io/2/nanosleep) - high-resolution sleep - [stime](https://manual.cs50.io/2/stime) - set time - [strftime](https://manual.cs50.io/3/strftime) - format date and time - [strftime\_l](https://manual.cs50.io/3/strftime_l) - format date and time - [strptime](https://manual.cs50.io/3/strptime) - convert a string representation of time to a time tm s... - [time](https://manual.cs50.io/2/time) - get time in seconds get time in seconds - [timegm](https://manual.cs50.io/3/timegm) - inverses of gmtime and localtime - [timelocal](https://manual.cs50.io/3/timelocal) - inverses of gmtime and localtime - [timer\_create](https://manual.cs50.io/2/timer_create) - create a POSIX per-process timer - [timer\_delete](https://manual.cs50.io/2/timer_delete) - delete a POSIX per-process timer - [timer\_getoverrun](https://manual.cs50.io/2/timer_getoverrun) - get overrun count for a POSIX per-process timer - [timer\_gettime](https://manual.cs50.io/2/timer_gettime) - arm/disarm and fetch state of POSIX per-process timer - [timer\_settime](https://manual.cs50.io/2/timer_settime) - arm/disarm and fetch state of POSIX per-process timer - [timezone](https://manual.cs50.io/3/timezone) - initialize time conversion information - [tzname](https://manual.cs50.io/3/tzname) - initialize time conversion information - [tzset](https://manual.cs50.io/3/tzset) - initialize time conversion information # [ulimit.h](https://manual.cs50.io/#ulimit.h) - [ulimit](https://manual.cs50.io/3/ulimit) - get and set user limits # [unistd.h](https://manual.cs50.io/#unistd.h) - [\_Exit](https://manual.cs50.io/2/_Exit) - terminate the calling process - [\_exit](https://manual.cs50.io/2/_exit) - terminate the calling process - [\_llseek](https://manual.cs50.io/2/_llseek) - reposition read/write file offset - [\_sysctl](https://manual.cs50.io/2/_sysctl) - read/write system parameters - [access](https://manual.cs50.io/2/access) - check user's permissions for a file - [acct](https://manual.cs50.io/2/acct) - switch process accounting on or off - [alarm](https://manual.cs50.io/2/alarm) - set an alarm clock for delivery of a signal - [arch\_prctl](https://manual.cs50.io/2/arch_prctl) - set architecture-specific thread state - [brk](https://manual.cs50.io/2/brk) - change data segment size - [capget](https://manual.cs50.io/2/capget) - set/get capabilities of thread(s) - [capset](https://manual.cs50.io/2/capset) - set/get capabilities of thread(s) - [chdir](https://manual.cs50.io/2/chdir) - change working directory - [chown](https://manual.cs50.io/2/chown) - change ownership of a file - [chown32](https://manual.cs50.io/2/chown32) - change ownership of a file - [chroot](https://manual.cs50.io/2/chroot) - change root directory - [close](https://manual.cs50.io/2/close) - close a file descriptor - [close\_range](https://manual.cs50.io/2/close_range) - close all file descriptors in a given range - [confstr](https://manual.cs50.io/3/confstr) - get configuration dependent string variables - [copy\_file\_range](https://manual.cs50.io/2/copy_file_range) - Copy a range of data from one file to another - [cuserid](https://manual.cs50.io/3/cuserid) - get username - [daemon](https://manual.cs50.io/3/daemon) - run in the background - [delete\_module](https://manual.cs50.io/2/delete_module) - unload a kernel module - [dup](https://manual.cs50.io/2/dup) - duplicate a file descriptor - [dup2](https://manual.cs50.io/2/dup2) - duplicate a file descriptor - [dup3](https://manual.cs50.io/2/dup3) - duplicate a file descriptor - [eaccess](https://manual.cs50.io/3/eaccess) - check effective user's permissions for a file - [encrypt](https://manual.cs50.io/3/encrypt) - encrypt 64-bit messages - [encrypt\_r](https://manual.cs50.io/3/encrypt_r) - encrypt 64-bit messages - [endusershell](https://manual.cs50.io/3/endusershell) - get permitted user shells - [euidaccess](https://manual.cs50.io/3/euidaccess) - check effective user's permissions for a file - [exec](https://manual.cs50.io/3/exec) - execute a file - [execl](https://manual.cs50.io/3/execl) - execute a file - [execle](https://manual.cs50.io/3/execle) - execute a file - [execlp](https://manual.cs50.io/3/execlp) - execute a file - [execv](https://manual.cs50.io/3/execv) - execute a file - [execve](https://manual.cs50.io/2/execve) - execute program - [execveat](https://manual.cs50.io/2/execveat) - execute program relative to a directory file descriptor - [execvp](https://manual.cs50.io/3/execvp) - execute a file - [execvpe](https://manual.cs50.io/3/execvpe) - execute a file - [exit](https://manual.cs50.io/2/exit) - terminate the calling process - [exit\_group](https://manual.cs50.io/2/exit_group) - exit all threads in a process - [faccessat](https://manual.cs50.io/2/faccessat) - check user's permissions for a file - [faccessat2](https://manual.cs50.io/2/faccessat2) - check user's permissions for a file - [fchdir](https://manual.cs50.io/2/fchdir) - change working directory - [fchown](https://manual.cs50.io/2/fchown) - change ownership of a file - [fchown32](https://manual.cs50.io/2/fchown32) - change ownership of a file - [fchownat](https://manual.cs50.io/2/fchownat) - change ownership of a file - [fdatasync](https://manual.cs50.io/2/fdatasync) - synchronize a file's in-core state with storage device - [fexecve](https://manual.cs50.io/3/fexecve) - execute program specified via file descriptor - [finit\_module](https://manual.cs50.io/2/finit_module) - load a kernel module - [fork](https://manual.cs50.io/2/fork) - create a child process - [fpathconf](https://manual.cs50.io/3/fpathconf) - get configuration values for files - [fsync](https://manual.cs50.io/2/fsync) - synchronize a file's in-core state with storage device - [ftruncate](https://manual.cs50.io/2/ftruncate) - truncate a file to a specified length - [ftruncate64](https://manual.cs50.io/2/ftruncate64) - truncate a file to a specified length - [futex](https://manual.cs50.io/2/futex) - fast user-space locking - [get\_current\_dir\_name](https://manual.cs50.io/3/get_current_dir_name) - get current working directory - [get\_robust\_list](https://manual.cs50.io/2/get_robust_list) - get/set list of robust futexes - [get\_thread\_area](https://manual.cs50.io/2/get_thread_area) - manipulate thread-local storage information - [getcwd](https://manual.cs50.io/2/getcwd) - get current working directory - [getcwd](https://manual.cs50.io/3/getcwd) - get current working directory - [getdents](https://manual.cs50.io/2/getdents) - get directory entries - [getdents64](https://manual.cs50.io/2/getdents64) - get directory entries - [getdomainname](https://manual.cs50.io/2/getdomainname) - get/set NIS domain name - [getdtablesize](https://manual.cs50.io/3/getdtablesize) - get file descriptor table size - [getegid](https://manual.cs50.io/2/getegid) - get group identity - [getegid32](https://manual.cs50.io/2/getegid32) - get group identity - [getentropy](https://manual.cs50.io/3/getentropy) - fill a buffer with random bytes - [geteuid](https://manual.cs50.io/2/geteuid) - get user identity - [geteuid32](https://manual.cs50.io/2/geteuid32) - get user identity - [getgid](https://manual.cs50.io/2/getgid) - get group identity - [getgid32](https://manual.cs50.io/2/getgid32) - get group identity - [getgroups](https://manual.cs50.io/2/getgroups) - get/set list of supplementary group IDs - [getgroups32](https://manual.cs50.io/2/getgroups32) - get/set list of supplementary group IDs - [gethostid](https://manual.cs50.io/3/gethostid) - get or set the unique identifier of the current host - [gethostname](https://manual.cs50.io/2/gethostname) - get/set hostname - [getlogin](https://manual.cs50.io/3/getlogin) - get username - [getlogin\_r](https://manual.cs50.io/3/getlogin_r) - get username - [getopt](https://manual.cs50.io/3/getopt) - Parse command-line options - [getopt\_long](https://manual.cs50.io/3/getopt_long) - Parse command-line options - [getopt\_long\_only](https://manual.cs50.io/3/getopt_long_only) - Parse command-line options - [getpagesize](https://manual.cs50.io/2/getpagesize) - get memory page size - [getpass](https://manual.cs50.io/3/getpass) - get a password - [getpgid](https://manual.cs50.io/2/getpgid) - set/get process group - [getpgrp](https://manual.cs50.io/2/getpgrp) - set/get process group - [getpid](https://manual.cs50.io/2/getpid) - get process identification - [getppid](https://manual.cs50.io/2/getppid) - get process identification - [getresgid](https://manual.cs50.io/2/getresgid) - get real, effective, and saved user/group IDs - [getresgid32](https://manual.cs50.io/2/getresgid32) - get real, effective, and saved user/group IDs - [getresuid](https://manual.cs50.io/2/getresuid) - get real, effective, and saved user/group IDs - [getresuid32](https://manual.cs50.io/2/getresuid32) - get real, effective, and saved user/group IDs - [getsid](https://manual.cs50.io/2/getsid) - get session ID - [gettid](https://manual.cs50.io/2/gettid) - get thread identification - [getuid](https://manual.cs50.io/2/getuid) - get user identity - [getuid32](https://manual.cs50.io/2/getuid32) - get user identity - [getusershell](https://manual.cs50.io/3/getusershell) - get permitted user shells - [getwd](https://manual.cs50.io/3/getwd) - get current working directory - [group\_member](https://manual.cs50.io/3/group_member) - test whether a process is in a group - [idle](https://manual.cs50.io/2/idle) - make process 0 idle - [init\_module](https://manual.cs50.io/2/init_module) - load a kernel module - [io\_cancel](https://manual.cs50.io/2/io_cancel) - cancel an outstanding asynchronous I/O operation - [io\_destroy](https://manual.cs50.io/2/io_destroy) - destroy an asynchronous I/O context - [io\_getevents](https://manual.cs50.io/2/io_getevents) - read asynchronous I/O events from the completion queue - [ioprio\_get](https://manual.cs50.io/2/ioprio_get) - get/set I/O scheduling class and priority - [ioprio\_set](https://manual.cs50.io/2/ioprio_set) - get/set I/O scheduling class and priority - [ipc](https://manual.cs50.io/2/ipc) - System V IPC system calls - [isatty](https://manual.cs50.io/3/isatty) - test whether a file descriptor refers to a terminal - [kcmp](https://manual.cs50.io/2/kcmp) - compare two processes to determine if they share a ker... - [kexec\_file\_load](https://manual.cs50.io/2/kexec_file_load) - load a new kernel for later execution - [kexec\_load](https://manual.cs50.io/2/kexec_load) - load a new kernel for later execution - [keyctl](https://manual.cs50.io/2/keyctl) - manipulate the kernel's key management facility - [klogctl](https://manual.cs50.io/3/klogctl) - read and/or clear kernel message ring buffer; set cons... - [lchown](https://manual.cs50.io/2/lchown) - change ownership of a file - [lchown32](https://manual.cs50.io/2/lchown32) - change ownership of a file - [link](https://manual.cs50.io/2/link) - make a new name for a file - [linkat](https://manual.cs50.io/2/linkat) - make a new name for a file - [llseek](https://manual.cs50.io/2/llseek) - reposition read/write file offset - [lockf](https://manual.cs50.io/3/lockf) - apply, test or remove a POSIX lock on an open file - [lookup\_dcookie](https://manual.cs50.io/2/lookup_dcookie) - return a directory entry's path - [lseek](https://manual.cs50.io/2/lseek) - reposition read/write file offset - [membarrier](https://manual.cs50.io/2/membarrier) - issue memory barriers on a set of threads - [memfd\_secret](https://manual.cs50.io/2/memfd_secret) - create an anonymous RAM-based file to access secret me... - [mmap2](https://manual.cs50.io/2/mmap2) - map files or devices into memory - [modify\_ldt](https://manual.cs50.io/2/modify_ldt) - get or set a per-process LDT entry - [mount\_setattr](https://manual.cs50.io/2/mount_setattr) - change properties of a mount or mount tree - [mq\_getsetattr](https://manual.cs50.io/2/mq_getsetattr) - get/set message queue attributes - [nice](https://manual.cs50.io/2/nice) - change process priority - [openat2](https://manual.cs50.io/2/openat2) - open and possibly create a file (extended) - [optarg](https://manual.cs50.io/3/optarg) - Parse command-line options - [opterr](https://manual.cs50.io/3/opterr) - Parse command-line options - [optind](https://manual.cs50.io/3/optind) - Parse command-line options - [optopt](https://manual.cs50.io/3/optopt) - Parse command-line options - [pathconf](https://manual.cs50.io/3/pathconf) - get configuration values for files - [pause](https://manual.cs50.io/2/pause) - wait for signal - [perf\_event\_open](https://manual.cs50.io/2/perf_event_open) - set up performance monitoring - [pidfd\_getfd](https://manual.cs50.io/2/pidfd_getfd) - obtain a duplicate of another process's file descriptor - [pidfd\_open](https://manual.cs50.io/2/pidfd_open) - obtain a file descriptor that refers to a process - [pidfd\_send\_signal](https://manual.cs50.io/2/pidfd_send_signal) - send a signal to a process specified by a file descri... - [pipe](https://manual.cs50.io/2/pipe) - create pipe - [pipe2](https://manual.cs50.io/2/pipe2) - create pipe - [pivot\_root](https://manual.cs50.io/2/pivot_root) - change the root mount - [pread](https://manual.cs50.io/2/pread) - read from or write to a file descriptor at a given offset - [pread64](https://manual.cs50.io/2/pread64) - read from or write to a file descriptor at a given offset - [profil](https://manual.cs50.io/3/profil) - execution time profile - [pwrite](https://manual.cs50.io/2/pwrite) - read from or write to a file descriptor at a given offset - [pwrite64](https://manual.cs50.io/2/pwrite64) - read from or write to a file descriptor at a given offset - [read](https://manual.cs50.io/2/read) - read from a file descriptor - [readdir](https://manual.cs50.io/2/readdir) - read directory entry - [readlink](https://manual.cs50.io/2/readlink) - read value of a symbolic link - [readlinkat](https://manual.cs50.io/2/readlinkat) - read value of a symbolic link - [reboot](https://manual.cs50.io/2/reboot) - reboot or enable/disable Ctrl-Alt-Del - [rmdir](https://manual.cs50.io/2/rmdir) - delete a directory - [rt\_sigqueueinfo](https://manual.cs50.io/2/rt_sigqueueinfo) - queue a signal and data - [rt\_tgsigqueueinfo](https://manual.cs50.io/2/rt_tgsigqueueinfo) - queue a signal and data - [s390\_guarded\_storage](https://manual.cs50.io/2/s390_guarded_storage) - operations with z/Architecture guarded storage fac... - [s390\_pci\_mmio\_read](https://manual.cs50.io/2/s390_pci_mmio_read) - transfer data to/from PCI MMIO memory page - [s390\_pci\_mmio\_write](https://manual.cs50.io/2/s390_pci_mmio_write) - transfer data to/from PCI MMIO memory page - [s390\_runtime\_instr](https://manual.cs50.io/2/s390_runtime_instr) - enable/disable s390 CPU run-time instrumentation - [s390\_sthyi](https://manual.cs50.io/2/s390_sthyi) - emulate STHYI instruction - [sbrk](https://manual.cs50.io/2/sbrk) - change data segment size - [sched\_getattr](https://manual.cs50.io/2/sched_getattr) - set and get scheduling policy and attributes - [sched\_setattr](https://manual.cs50.io/2/sched_setattr) - set and get scheduling policy and attributes - [seccomp](https://manual.cs50.io/2/seccomp) - operate on Secure Computing state of the process - [set\_robust\_list](https://manual.cs50.io/2/set_robust_list) - get/set list of robust futexes - [set\_thread\_area](https://manual.cs50.io/2/set_thread_area) - manipulate thread-local storage information - [set\_tid\_address](https://manual.cs50.io/2/set_tid_address) - set pointer to thread ID - [setdomainname](https://manual.cs50.io/2/setdomainname) - get/set NIS domain name - [setegid](https://manual.cs50.io/2/setegid) - set effective user or group ID - [seteuid](https://manual.cs50.io/2/seteuid) - set effective user or group ID - [setgid](https://manual.cs50.io/2/setgid) - set group identity - [setgid32](https://manual.cs50.io/2/setgid32) - set group identity - [setgroups](https://manual.cs50.io/2/setgroups) - get/set list of supplementary group IDs - [setgroups32](https://manual.cs50.io/2/setgroups32) - get/set list of supplementary group IDs - [sethostid](https://manual.cs50.io/3/sethostid) - get or set the unique identifier of the current host - [sethostname](https://manual.cs50.io/2/sethostname) - get/set hostname - [setkey](https://manual.cs50.io/3/setkey) - encrypt 64-bit messages - [setkey\_r](https://manual.cs50.io/3/setkey_r) - encrypt 64-bit messages - [setpgid](https://manual.cs50.io/2/setpgid) - set/get process group - [setpgrp](https://manual.cs50.io/2/setpgrp) - set/get process group - [setregid](https://manual.cs50.io/2/setregid) - set real and/or effective user or group ID - [setregid32](https://manual.cs50.io/2/setregid32) - set real and/or effective user or group ID - [setresgid](https://manual.cs50.io/2/setresgid) - set real, effective, and saved user or group ID - [setresgid32](https://manual.cs50.io/2/setresgid32) - set real, effective, and saved user or group ID - [setresuid](https://manual.cs50.io/2/setresuid) - set real, effective, and saved user or group ID - [setresuid32](https://manual.cs50.io/2/setresuid32) - set real, effective, and saved user or group ID - [setreuid](https://manual.cs50.io/2/setreuid) - set real and/or effective user or group ID - [setreuid32](https://manual.cs50.io/2/setreuid32) - set real and/or effective user or group ID - [setsid](https://manual.cs50.io/2/setsid) - creates a session and sets the process group ID - [setuid](https://manual.cs50.io/2/setuid) - set user identity - [setuid32](https://manual.cs50.io/2/setuid32) - set user identity - [setup](https://manual.cs50.io/2/setup) - setup devices and filesystems, mount root filesystem - [setusershell](https://manual.cs50.io/3/setusershell) - get permitted user shells - [sgetmask](https://manual.cs50.io/2/sgetmask) - manipulation of signal mask (obsolete) - [sleep](https://manual.cs50.io/3/sleep) - sleep for a specified number of seconds - [socketcall](https://manual.cs50.io/2/socketcall) - socket system calls - [spu\_create](https://manual.cs50.io/2/spu_create) - create a new spu context - [spu\_run](https://manual.cs50.io/2/spu_run) - execute an SPU context - [ssetmask](https://manual.cs50.io/2/ssetmask) - manipulation of signal mask (obsolete) - [subpage\_prot](https://manual.cs50.io/2/subpage_prot) - define a subpage protection for an address range - [swab](https://manual.cs50.io/3/swab) - swap adjacent bytes - [symlink](https://manual.cs50.io/2/symlink) - make a new name for a file - [symlinkat](https://manual.cs50.io/2/symlinkat) - make a new name for a file - [sync](https://manual.cs50.io/2/sync) - commit filesystem caches to disk - [syncfs](https://manual.cs50.io/2/syncfs) - commit filesystem caches to disk - [syscall](https://manual.cs50.io/2/syscall) - indirect system call - [sysconf](https://manual.cs50.io/3/sysconf) - get configuration information at run time - [sysctl](https://manual.cs50.io/2/sysctl) - read/write system parameters - [syslog](https://manual.cs50.io/2/syslog) - read and/or clear kernel message ring buffer; set cons... - [tcgetpgrp](https://manual.cs50.io/3/tcgetpgrp) - get and set terminal foreground process group - [tcsetpgrp](https://manual.cs50.io/3/tcsetpgrp) - get and set terminal foreground process group - [tgkill](https://manual.cs50.io/2/tgkill) - send a signal to a thread - [tkill](https://manual.cs50.io/2/tkill) - send a signal to a thread - [truncate](https://manual.cs50.io/2/truncate) - truncate a file to a specified length - [truncate64](https://manual.cs50.io/2/truncate64) - truncate a file to a specified length - [ttyname](https://manual.cs50.io/3/ttyname) - return name of a terminal - [ttyname\_r](https://manual.cs50.io/3/ttyname_r) - return name of a terminal - [ualarm](https://manual.cs50.io/3/ualarm) - schedule signal after given number of microseconds - [unlink](https://manual.cs50.io/2/unlink) - delete a name and possibly the file it refers to - [unlinkat](https://manual.cs50.io/2/unlinkat) - delete a name and possibly the file it refers to - [uselib](https://manual.cs50.io/2/uselib) - load shared library - [userfaultfd](https://manual.cs50.io/2/userfaultfd) - create a file descriptor for handling page faults in u... - [usleep](https://manual.cs50.io/3/usleep) - suspend execution for microsecond intervals - [vfork](https://manual.cs50.io/2/vfork) - create a child process and block parent - [vhangup](https://manual.cs50.io/2/vhangup) - virtually hangup the current terminal - [write](https://manual.cs50.io/2/write) - write to a file descriptor # [utime.h](https://manual.cs50.io/#utime.h) - [utime](https://manual.cs50.io/2/utime) - change file last access and modification times - [utimes](https://manual.cs50.io/2/utimes) - change file last access and modification times # [utmpx.h](https://manual.cs50.io/#utmpx.h) - [getutmp](https://manual.cs50.io/3/getutmp) - copy utmp structure to utmpx, and vice versa - [getutmpx](https://manual.cs50.io/3/getutmpx) - copy utmp structure to utmpx, and vice versa # [wchar.h](https://manual.cs50.io/#wchar.h) - [btowc](https://manual.cs50.io/3/btowc) - convert single byte to wide character - [fgetws](https://manual.cs50.io/3/fgetws) - read a wide-character string from a FILE stream - [fputws](https://manual.cs50.io/3/fputws) - write a wide-character string to a FILE stream - [fwide](https://manual.cs50.io/3/fwide) - set and determine the orientation of a FILE stream - [getwchar](https://manual.cs50.io/3/getwchar) - read a wide character from standard input - [mbrlen](https://manual.cs50.io/3/mbrlen) - determine number of bytes in next multibyte character - [mbrtowc](https://manual.cs50.io/3/mbrtowc) - convert a multibyte sequence to a wide character - [mbsinit](https://manual.cs50.io/3/mbsinit) - test for initial shift state - [mbsnrtowcs](https://manual.cs50.io/3/mbsnrtowcs) - convert a multibyte string to a wide-character string - [mbsrtowcs](https://manual.cs50.io/3/mbsrtowcs) - convert a multibyte string to a wide-character string ... - [putwchar](https://manual.cs50.io/3/putwchar) - write a wide character to standard output - [ungetwc](https://manual.cs50.io/3/ungetwc) - push back a wide character onto a FILE stream - [wcpcpy](https://manual.cs50.io/3/wcpcpy) - copy a wide-character string, returning a pointer to i... - [wcpncpy](https://manual.cs50.io/3/wcpncpy) - copy a fixed-size string of wide characters, returning... - [wcrtomb](https://manual.cs50.io/3/wcrtomb) - convert a wide character to a multibyte sequence - [wcscasecmp](https://manual.cs50.io/3/wcscasecmp) - compare two wide-character strings, ignoring case - [wcscat](https://manual.cs50.io/3/wcscat) - concatenate two wide-character strings - [wcschr](https://manual.cs50.io/3/wcschr) - search a wide character in a wide-character string - [wcscmp](https://manual.cs50.io/3/wcscmp) - compare two wide-character strings - [wcscpy](https://manual.cs50.io/3/wcscpy) - copy a wide-character string - [wcscspn](https://manual.cs50.io/3/wcscspn) - search a wide-character string for any of a set of wid... - [wcsdup](https://manual.cs50.io/3/wcsdup) - duplicate a wide-character string - [wcslen](https://manual.cs50.io/3/wcslen) - determine the length of a wide-character string - [wcsncasecmp](https://manual.cs50.io/3/wcsncasecmp) - compare two fixed-size wide-character strings, ignorin... - [wcsncat](https://manual.cs50.io/3/wcsncat) - concatenate two wide-character strings - [wcsncmp](https://manual.cs50.io/3/wcsncmp) - compare two fixed-size wide-character strings - [wcsncpy](https://manual.cs50.io/3/wcsncpy) - copy a fixed-size string of wide characters - [wcsnlen](https://manual.cs50.io/3/wcsnlen) - determine the length of a fixed-size wide-character st... - [wcsnrtombs](https://manual.cs50.io/3/wcsnrtombs) - convert a wide-character string to a multibyte string - [wcspbrk](https://manual.cs50.io/3/wcspbrk) - search a wide-character string for any of a set of wid... - [wcsrchr](https://manual.cs50.io/3/wcsrchr) - search a wide character in a wide-character string - [wcsrtombs](https://manual.cs50.io/3/wcsrtombs) - convert a wide-character string to a multibyte string - [wcsspn](https://manual.cs50.io/3/wcsspn) - get length of a prefix wide-character substring - [wcsstr](https://manual.cs50.io/3/wcsstr) - locate a substring in a wide-character string - [wcstok](https://manual.cs50.io/3/wcstok) - split wide-character string into tokens - [wcswidth](https://manual.cs50.io/3/wcswidth) - determine columns needed for a fixed-size wide-charact... - [wctob](https://manual.cs50.io/3/wctob) - try to represent a wide character as a single byte - [wcwidth](https://manual.cs50.io/3/wcwidth) - determine columns needed for a wide character - [wmemchr](https://manual.cs50.io/3/wmemchr) - search a wide character in a wide-character array - [wmemcmp](https://manual.cs50.io/3/wmemcmp) - compare two arrays of wide-characters - [wmemcpy](https://manual.cs50.io/3/wmemcpy) - copy an array of wide-characters - [wmemmove](https://manual.cs50.io/3/wmemmove) - copy an array of wide-characters - [wmemset](https://manual.cs50.io/3/wmemset) - fill an array of wide-characters with a constant wide ... # [wctype.h](https://manual.cs50.io/#wctype.h) - [iswalnum](https://manual.cs50.io/3/iswalnum) - test for alphanumeric wide character - [iswalpha](https://manual.cs50.io/3/iswalpha) - test for alphabetic wide character - [iswblank](https://manual.cs50.io/3/iswblank) - test for whitespace wide character - [iswcntrl](https://manual.cs50.io/3/iswcntrl) - test for control wide character - [iswctype](https://manual.cs50.io/3/iswctype) - wide-character classification - [iswdigit](https://manual.cs50.io/3/iswdigit) - test for decimal digit wide character - [iswgraph](https://manual.cs50.io/3/iswgraph) - test for graphic wide character - [iswlower](https://manual.cs50.io/3/iswlower) - test for lowercase wide character - [iswprint](https://manual.cs50.io/3/iswprint) - test for printing wide character - [iswpunct](https://manual.cs50.io/3/iswpunct) - test for punctuation or symbolic wide character - [iswspace](https://manual.cs50.io/3/iswspace) - test for whitespace wide character - [iswupper](https://manual.cs50.io/3/iswupper) - test for uppercase wide character - [iswxdigit](https://manual.cs50.io/3/iswxdigit) - test for hexadecimal digit wide character - [towctrans](https://manual.cs50.io/3/towctrans) - wide-character transliteration - [towlower](https://manual.cs50.io/3/towlower) - convert a wide character to lowercase - [towlower\_l](https://manual.cs50.io/3/towlower_l) - convert a wide character to lowercase - [towupper](https://manual.cs50.io/3/towupper) - convert a wide character to uppercase - [towupper\_l](https://manual.cs50.io/3/towupper_l) - convert a wide character to uppercase - [wctrans](https://manual.cs50.io/3/wctrans) - wide-character translation mapping - [wctype](https://manual.cs50.io/3/wctype) - wide-character classification # [wordexp.h](https://manual.cs50.io/#wordexp.h) - [wordexp](https://manual.cs50.io/3/wordexp) - perform word expansion like a posix-shell - [wordfree](https://manual.cs50.io/3/wordfree) - perform word expansion like a posix-shell
Readable Markdown	Manual pages for the C standard library, the C POSIX library, and the CS50 Library for [those less comfortable](). ## [aio.h](https://manual.cs50.io/#aio.h) - [aio\_cancel](https://manual.cs50.io/3/aio_cancel) - cancel an outstanding asynchronous I/O request - [aio\_error](https://manual.cs50.io/3/aio_error) - get error status of asynchronous I/O operation - [aio\_fsync](https://manual.cs50.io/3/aio_fsync) - asynchronous file synchronization - [aio\_init](https://manual.cs50.io/3/aio_init) - asynchronous I/O initialization - [aio\_read](https://manual.cs50.io/3/aio_read) - asynchronous read - [aio\_return](https://manual.cs50.io/3/aio_return) - get return status of asynchronous I/O operation - [aio\_suspend](https://manual.cs50.io/3/aio_suspend) - wait for asynchronous I/O operation or timeout - [aio\_write](https://manual.cs50.io/3/aio_write) - asynchronous write - [lio\_listio](https://manual.cs50.io/3/lio_listio) - initiate a list of I/O requests ## [arpa/inet.h](https://manual.cs50.io/#arpa/inet.h) - [byteorder](https://manual.cs50.io/3/byteorder) - convert values between host and network byte order - [htonl](https://manual.cs50.io/3/htonl) - convert values between host and network byte order - [htons](https://manual.cs50.io/3/htons) - convert values between host and network byte order - [inet\_net\_ntop](https://manual.cs50.io/3/inet_net_ntop) - Internet network number conversion - [inet\_net\_pton](https://manual.cs50.io/3/inet_net_pton) - Internet network number conversion - [inet\_ntop](https://manual.cs50.io/3/inet_ntop) - convert IPv4 and IPv6 addresses from binary to text form - [inet\_pton](https://manual.cs50.io/3/inet_pton) - convert IPv4 and IPv6 addresses from text to binary form - [ntohl](https://manual.cs50.io/3/ntohl) - convert values between host and network byte order - [ntohs](https://manual.cs50.io/3/ntohs) - convert values between host and network byte order ## [assert.h](https://manual.cs50.io/#assert.h) - [\_Static\_assert](https://manual.cs50.io/3/_Static_assert) - fail compilation if assertion is false - [assert](https://manual.cs50.io/3/assert) - abort the program if assertion is false - [assert\_perror](https://manual.cs50.io/3/assert_perror) - test errnum and abort - [static\_assert](https://manual.cs50.io/3/static_assert) - fail compilation if assertion is false ## [complex.h](https://manual.cs50.io/#complex.h) - [cabs](https://manual.cs50.io/3/cabs) - absolute value of a complex number - [cabsf](https://manual.cs50.io/3/cabsf) - absolute value of a complex number - [cabsl](https://manual.cs50.io/3/cabsl) - absolute value of a complex number - [cacos](https://manual.cs50.io/3/cacos) - complex arc cosine - [cacosf](https://manual.cs50.io/3/cacosf) - complex arc cosine - [cacosh](https://manual.cs50.io/3/cacosh) - complex arc hyperbolic cosine - [cacoshf](https://manual.cs50.io/3/cacoshf) - complex arc hyperbolic cosine - [cacoshl](https://manual.cs50.io/3/cacoshl) - complex arc hyperbolic cosine - [cacosl](https://manual.cs50.io/3/cacosl) - complex arc cosine - [carg](https://manual.cs50.io/3/carg) - calculate the complex argument - [cargf](https://manual.cs50.io/3/cargf) - calculate the complex argument - [cargl](https://manual.cs50.io/3/cargl) - calculate the complex argument - [casin](https://manual.cs50.io/3/casin) - complex arc sine - [casinf](https://manual.cs50.io/3/casinf) - complex arc sine - [casinh](https://manual.cs50.io/3/casinh) - complex arc sine hyperbolic - [casinhf](https://manual.cs50.io/3/casinhf) - complex arc sine hyperbolic - [casinhl](https://manual.cs50.io/3/casinhl) - complex arc sine hyperbolic - [casinl](https://manual.cs50.io/3/casinl) - complex arc sine - [catan](https://manual.cs50.io/3/catan) - complex arc tangents - [catanf](https://manual.cs50.io/3/catanf) - complex arc tangents - [catanh](https://manual.cs50.io/3/catanh) - complex arc tangents hyperbolic - [catanhf](https://manual.cs50.io/3/catanhf) - complex arc tangents hyperbolic - [catanhl](https://manual.cs50.io/3/catanhl) - complex arc tangents hyperbolic - [catanl](https://manual.cs50.io/3/catanl) - complex arc tangents - [ccos](https://manual.cs50.io/3/ccos) - complex cosine function - [ccosf](https://manual.cs50.io/3/ccosf) - complex cosine function - [ccosh](https://manual.cs50.io/3/ccosh) - complex hyperbolic cosine - [ccoshf](https://manual.cs50.io/3/ccoshf) - complex hyperbolic cosine - [ccoshl](https://manual.cs50.io/3/ccoshl) - complex hyperbolic cosine - [ccosl](https://manual.cs50.io/3/ccosl) - complex cosine function - [cexp](https://manual.cs50.io/3/cexp) - complex exponential function - [cexp2](https://manual.cs50.io/3/cexp2) - base-2 exponent of a complex number - [cexp2f](https://manual.cs50.io/3/cexp2f) - base-2 exponent of a complex number - [cexp2l](https://manual.cs50.io/3/cexp2l) - base-2 exponent of a complex number - [cexpf](https://manual.cs50.io/3/cexpf) - complex exponential function - [cexpl](https://manual.cs50.io/3/cexpl) - complex exponential function - [cimag](https://manual.cs50.io/3/cimag) - get imaginary part of a complex number - [cimagf](https://manual.cs50.io/3/cimagf) - get imaginary part of a complex number - [cimagl](https://manual.cs50.io/3/cimagl) - get imaginary part of a complex number - [clog](https://manual.cs50.io/3/clog) - natural logarithm of a complex number - [clog10](https://manual.cs50.io/3/clog10) - base-10 logarithm of a complex number - [clog10f](https://manual.cs50.io/3/clog10f) - base-10 logarithm of a complex number - [clog10l](https://manual.cs50.io/3/clog10l) - base-10 logarithm of a complex number - [clog2](https://manual.cs50.io/3/clog2) - base-2 logarithm of a complex number - [clog2f](https://manual.cs50.io/3/clog2f) - base-2 logarithm of a complex number - [clog2l](https://manual.cs50.io/3/clog2l) - base-2 logarithm of a complex number - [clogf](https://manual.cs50.io/3/clogf) - natural logarithm of a complex number - [clogl](https://manual.cs50.io/3/clogl) - natural logarithm of a complex number - [complex](https://manual.cs50.io/7/complex) - basics of complex mathematics - [conj](https://manual.cs50.io/3/conj) - calculate the complex conjugate - [conjf](https://manual.cs50.io/3/conjf) - calculate the complex conjugate - [conjl](https://manual.cs50.io/3/conjl) - calculate the complex conjugate - [cpow](https://manual.cs50.io/3/cpow) - complex power function - [cpowf](https://manual.cs50.io/3/cpowf) - complex power function - [cpowl](https://manual.cs50.io/3/cpowl) - complex power function - [cproj](https://manual.cs50.io/3/cproj) - project into Riemann Sphere - [cprojf](https://manual.cs50.io/3/cprojf) - project into Riemann Sphere - [cprojl](https://manual.cs50.io/3/cprojl) - project into Riemann Sphere - [creal](https://manual.cs50.io/3/creal) - get real part of a complex number - [crealf](https://manual.cs50.io/3/crealf) - get real part of a complex number - [creall](https://manual.cs50.io/3/creall) - get real part of a complex number - [csin](https://manual.cs50.io/3/csin) - complex sine function - [csinf](https://manual.cs50.io/3/csinf) - complex sine function - [csinh](https://manual.cs50.io/3/csinh) - complex hyperbolic sine - [csinhf](https://manual.cs50.io/3/csinhf) - complex hyperbolic sine - [csinhl](https://manual.cs50.io/3/csinhl) - complex hyperbolic sine - [csinl](https://manual.cs50.io/3/csinl) - complex sine function - [csqrt](https://manual.cs50.io/3/csqrt) - complex square root - [csqrtf](https://manual.cs50.io/3/csqrtf) - complex square root - [csqrtl](https://manual.cs50.io/3/csqrtl) - complex square root - [ctan](https://manual.cs50.io/3/ctan) - complex tangent function - [ctanf](https://manual.cs50.io/3/ctanf) - complex tangent function - [ctanh](https://manual.cs50.io/3/ctanh) - complex hyperbolic tangent - [ctanhf](https://manual.cs50.io/3/ctanhf) - complex hyperbolic tangent - [ctanhl](https://manual.cs50.io/3/ctanhl) - complex hyperbolic tangent - [ctanl](https://manual.cs50.io/3/ctanl) - complex tangent function - [get\_char](https://manual.cs50.io/3/get_char) - prompts user for a line of text from stdin and returns... prompt a user for a `char` - [get\_double](https://manual.cs50.io/3/get_double) - prompts user for a line of text from stdin and returns... prompt a user for a `double` - [get\_float](https://manual.cs50.io/3/get_float) - prompts user for a line of text from stdin and returns... prompt a user for a `float` - [get\_int](https://manual.cs50.io/3/get_int) - prompts user for a line of text from stdin and returns... prompt a user for an `int` - [get\_long](https://manual.cs50.io/3/get_long) - prompts user for a line of text from stdin and returns... prompt a user for an `long` - [get\_long\_long](https://manual.cs50.io/3/get_long_long) - prompts user for a line of text from stdin and returns... - [get\_string](https://manual.cs50.io/3/get_string) - prompts user for a line of text from stdin and returns... prompt a user for a `string` ## [ctype.h](https://manual.cs50.io/#ctype.h) - [isalnum](https://manual.cs50.io/3/isalnum) - character classification functions check whether a character is alphanumeric - [isalnum\_l](https://manual.cs50.io/3/isalnum_l) - character classification functions - [isalpha](https://manual.cs50.io/3/isalpha) - character classification functions check whether a character is alphabetical - [isalpha\_l](https://manual.cs50.io/3/isalpha_l) - character classification functions - [isascii](https://manual.cs50.io/3/isascii) - character classification functions - [isascii\_l](https://manual.cs50.io/3/isascii_l) - character classification functions - [isblank](https://manual.cs50.io/3/isblank) - character classification functions check whether a character is blank (i.e., a space or tab) - [isblank\_l](https://manual.cs50.io/3/isblank_l) - character classification functions - [iscntrl](https://manual.cs50.io/3/iscntrl) - character classification functions - [iscntrl\_l](https://manual.cs50.io/3/iscntrl_l) - character classification functions - [isdigit](https://manual.cs50.io/3/isdigit) - character classification functions check whether a character is a digit - [isdigit\_l](https://manual.cs50.io/3/isdigit_l) - character classification functions - [isgraph](https://manual.cs50.io/3/isgraph) - character classification functions - [isgraph\_l](https://manual.cs50.io/3/isgraph_l) - character classification functions - [islower](https://manual.cs50.io/3/islower) - character classification functions check whether a character is lowercase - [islower\_l](https://manual.cs50.io/3/islower_l) - character classification functions - [isprint](https://manual.cs50.io/3/isprint) - character classification functions - [isprint\_l](https://manual.cs50.io/3/isprint_l) - character classification functions - [ispunct](https://manual.cs50.io/3/ispunct) - character classification functions check whether a character is punctuation - [ispunct\_l](https://manual.cs50.io/3/ispunct_l) - character classification functions - [isspace](https://manual.cs50.io/3/isspace) - character classification functions check whether a character is whitespace (e.g., a newline, space, or tab) - [isspace\_l](https://manual.cs50.io/3/isspace_l) - character classification functions - [isupper](https://manual.cs50.io/3/isupper) - character classification functions check whether a character is uppercase - [isupper\_l](https://manual.cs50.io/3/isupper_l) - character classification functions - [isxdigit](https://manual.cs50.io/3/isxdigit) - character classification functions - [isxdigit\_l](https://manual.cs50.io/3/isxdigit_l) - character classification functions - [toascii](https://manual.cs50.io/3/toascii) - convert character to ASCII - [tolower](https://manual.cs50.io/3/tolower) - convert uppercase or lowercase convert a `char` to lowercase - [tolower\_l](https://manual.cs50.io/3/tolower_l) - convert uppercase or lowercase - [toupper](https://manual.cs50.io/3/toupper) - convert uppercase or lowercase convert a `char` to uppercase - [toupper\_l](https://manual.cs50.io/3/toupper_l) - convert uppercase or lowercase ## [dirent.h](https://manual.cs50.io/#dirent.h) - [alphasort](https://manual.cs50.io/3/alphasort) - scan a directory for matching entries - [getdirentries](https://manual.cs50.io/3/getdirentries) - get directory entries in a filesystem-independent format - [readdir](https://manual.cs50.io/3/readdir) - read a directory - [readdir\_r](https://manual.cs50.io/3/readdir_r) - read a directory - [scandir](https://manual.cs50.io/3/scandir) - scan a directory for matching entries - [scandirat](https://manual.cs50.io/3/scandirat) - scan a directory for matching entries - [seekdir](https://manual.cs50.io/3/seekdir) - set the position of the next readdir() call in the dir... - [telldir](https://manual.cs50.io/3/telldir) - return current location in directory stream - [versionsort](https://manual.cs50.io/3/versionsort) - scan a directory for matching entries ## [dlfcn.h](https://manual.cs50.io/#dlfcn.h) - [dladdr](https://manual.cs50.io/3/dladdr) - translate address to symbolic information - [dladdr1](https://manual.cs50.io/3/dladdr1) - translate address to symbolic information - [dlclose](https://manual.cs50.io/3/dlclose) - open and close a shared object - [dlerror](https://manual.cs50.io/3/dlerror) - obtain error diagnostic for functions in the dlopen API - [dlmopen](https://manual.cs50.io/3/dlmopen) - open and close a shared object - [dlopen](https://manual.cs50.io/3/dlopen) - open and close a shared object - [dlsym](https://manual.cs50.io/3/dlsym) - obtain address of a symbol in a shared object or execu... - [dlvsym](https://manual.cs50.io/3/dlvsym) - obtain address of a symbol in a shared object or execu... ## [errno.h](https://manual.cs50.io/#errno.h) - [errno](https://manual.cs50.io/3/errno) - number of last error - [program\_invocation\_name](https://manual.cs50.io/3/program_invocation_name) - obtain name used to invoke calling program - [program\_invocation\_short\_name](https://manual.cs50.io/3/program_invocation_short_name) - obtain name used to invoke calling program ## [fcntl.h](https://manual.cs50.io/#fcntl.h) - [arm\_fadvise](https://manual.cs50.io/2/arm_fadvise) - predeclare an access pattern for file data - [arm\_fadvise64\_64](https://manual.cs50.io/2/arm_fadvise64_64) - predeclare an access pattern for file data - [arm\_sync\_file\_range](https://manual.cs50.io/2/arm_sync_file_range) - sync a file segment with disk - [creat](https://manual.cs50.io/2/creat) - open and possibly create a file - [fadvise64](https://manual.cs50.io/2/fadvise64) - predeclare an access pattern for file data - [fadvise64\_64](https://manual.cs50.io/2/fadvise64_64) - predeclare an access pattern for file data - [fallocate](https://manual.cs50.io/2/fallocate) - manipulate file space - [fcntl](https://manual.cs50.io/2/fcntl) - manipulate file descriptor - [fcntl64](https://manual.cs50.io/2/fcntl64) - manipulate file descriptor - [name\_to\_handle\_at](https://manual.cs50.io/2/name_to_handle_at) - obtain handle for a pathname and open file via a handle - [open](https://manual.cs50.io/2/open) - open and possibly create a file - [open\_by\_handle\_at](https://manual.cs50.io/2/open_by_handle_at) - obtain handle for a pathname and open file via a handle - [openat](https://manual.cs50.io/2/openat) - open and possibly create a file - [posix\_fadvise](https://manual.cs50.io/2/posix_fadvise) - predeclare an access pattern for file data - [posix\_fallocate](https://manual.cs50.io/3/posix_fallocate) - allocate file space - [readahead](https://manual.cs50.io/2/readahead) - initiate file readahead into page cache - [splice](https://manual.cs50.io/2/splice) - splice data to/from a pipe - [sync\_file\_range](https://manual.cs50.io/2/sync_file_range) - sync a file segment with disk - [sync\_file\_range2](https://manual.cs50.io/2/sync_file_range2) - sync a file segment with disk - [tee](https://manual.cs50.io/2/tee) - duplicating pipe content - [vmsplice](https://manual.cs50.io/2/vmsplice) - splice user pages to/from a pipe ## [fenv.h](https://manual.cs50.io/#fenv.h) - [feclearexcept](https://manual.cs50.io/3/feclearexcept) - floating-point rounding and exception handling - [fedisableexcept](https://manual.cs50.io/3/fedisableexcept) - floating-point rounding and exception handling - [feenableexcept](https://manual.cs50.io/3/feenableexcept) - floating-point rounding and exception handling - [fegetenv](https://manual.cs50.io/3/fegetenv) - floating-point rounding and exception handling - [fegetexcept](https://manual.cs50.io/3/fegetexcept) - floating-point rounding and exception handling - [fegetexceptflag](https://manual.cs50.io/3/fegetexceptflag) - floating-point rounding and exception handling - [fegetround](https://manual.cs50.io/3/fegetround) - floating-point rounding and exception handling - [feholdexcept](https://manual.cs50.io/3/feholdexcept) - floating-point rounding and exception handling - [fenv](https://manual.cs50.io/3/fenv) - floating-point rounding and exception handling - [feraiseexcept](https://manual.cs50.io/3/feraiseexcept) - floating-point rounding and exception handling - [fesetenv](https://manual.cs50.io/3/fesetenv) - floating-point rounding and exception handling - [fesetexceptflag](https://manual.cs50.io/3/fesetexceptflag) - floating-point rounding and exception handling - [fesetround](https://manual.cs50.io/3/fesetround) - floating-point rounding and exception handling - [fetestexcept](https://manual.cs50.io/3/fetestexcept) - floating-point rounding and exception handling - [feupdateenv](https://manual.cs50.io/3/feupdateenv) - floating-point rounding and exception handling ## [fmtmsg.h](https://manual.cs50.io/#fmtmsg.h) - [addseverity](https://manual.cs50.io/3/addseverity) - introduce new severity classes - [fmtmsg](https://manual.cs50.io/3/fmtmsg) - print formatted error messages ## [fnmatch.h](https://manual.cs50.io/#fnmatch.h) - [fnmatch](https://manual.cs50.io/3/fnmatch) - match filename or pathname ## [ftw.h](https://manual.cs50.io/#ftw.h) - [ftw](https://manual.cs50.io/3/ftw) - file tree walk - [nftw](https://manual.cs50.io/3/nftw) - file tree walk ## [glob.h](https://manual.cs50.io/#glob.h) - [glob](https://manual.cs50.io/3/glob) - find pathnames matching a pattern, free memory from gl... - [globfree](https://manual.cs50.io/3/globfree) - find pathnames matching a pattern, free memory from gl... ## [grp.h](https://manual.cs50.io/#grp.h) - [fgetgrent\_r](https://manual.cs50.io/3/fgetgrent_r) - get group file entry reentrantly - [getgrent\_r](https://manual.cs50.io/3/getgrent_r) - get group file entry reentrantly - [getgrouplist](https://manual.cs50.io/3/getgrouplist) - get list of groups to which a user belongs - [putgrent](https://manual.cs50.io/3/putgrent) - write a group database entry to a file ## [iconv.h](https://manual.cs50.io/#iconv.h) - [iconv](https://manual.cs50.io/3/iconv) - perform character set conversion - [iconv\_close](https://manual.cs50.io/3/iconv_close) - deallocate descriptor for character set conversion - [iconv\_open](https://manual.cs50.io/3/iconv_open) - allocate descriptor for character set conversion ## [inttypes.h](https://manual.cs50.io/#inttypes.h) - [strtoimax](https://manual.cs50.io/3/strtoimax) - convert string to integer - [strtoumax](https://manual.cs50.io/3/strtoumax) - convert string to integer ## [langinfo.h](https://manual.cs50.io/#langinfo.h) - [nl\_langinfo](https://manual.cs50.io/3/nl_langinfo) - query language and locale information - [nl\_langinfo\_l](https://manual.cs50.io/3/nl_langinfo_l) - query language and locale information ## [libgen.h](https://manual.cs50.io/#libgen.h) - [basename](https://manual.cs50.io/3/basename) - parse pathname components - [dirname](https://manual.cs50.io/3/dirname) - parse pathname components ## [limits.h](https://manual.cs50.io/#limits.h) - [MB\_LEN\_MAX](https://manual.cs50.io/3/MB_LEN_MAX) - maximum multibyte length of a character across all loc... - [realpath](https://manual.cs50.io/3/realpath) - return the canonicalized absolute pathname ## [locale.h](https://manual.cs50.io/#locale.h) - [duplocale](https://manual.cs50.io/3/duplocale) - duplicate a locale object - [freelocale](https://manual.cs50.io/3/freelocale) - create, modify, and free a locale object - [locale](https://manual.cs50.io/7/locale) - description of multilanguage support - [localeconv](https://manual.cs50.io/3/localeconv) - get numeric formatting information - [newlocale](https://manual.cs50.io/3/newlocale) - create, modify, and free a locale object - [setlocale](https://manual.cs50.io/3/setlocale) - set the current locale - [uselocale](https://manual.cs50.io/3/uselocale) - set/get the locale for the calling thread ## [math.h](https://manual.cs50.io/#math.h) - [acos](https://manual.cs50.io/3/acos) - arc cosine function - [acosf](https://manual.cs50.io/3/acosf) - arc cosine function - [acosh](https://manual.cs50.io/3/acosh) - inverse hyperbolic cosine function - [acoshf](https://manual.cs50.io/3/acoshf) - inverse hyperbolic cosine function - [acoshl](https://manual.cs50.io/3/acoshl) - inverse hyperbolic cosine function - [acosl](https://manual.cs50.io/3/acosl) - arc cosine function - [asin](https://manual.cs50.io/3/asin) - arc sine function - [asinf](https://manual.cs50.io/3/asinf) - arc sine function - [asinh](https://manual.cs50.io/3/asinh) - inverse hyperbolic sine function - [asinhf](https://manual.cs50.io/3/asinhf) - inverse hyperbolic sine function - [asinhl](https://manual.cs50.io/3/asinhl) - inverse hyperbolic sine function - [asinl](https://manual.cs50.io/3/asinl) - arc sine function - [atan](https://manual.cs50.io/3/atan) - arc tangent function - [atan2](https://manual.cs50.io/3/atan2) - arc tangent function of two variables - [atan2f](https://manual.cs50.io/3/atan2f) - arc tangent function of two variables - [atan2l](https://manual.cs50.io/3/atan2l) - arc tangent function of two variables - [atanf](https://manual.cs50.io/3/atanf) - arc tangent function - [atanh](https://manual.cs50.io/3/atanh) - inverse hyperbolic tangent function - [atanhf](https://manual.cs50.io/3/atanhf) - inverse hyperbolic tangent function - [atanhl](https://manual.cs50.io/3/atanhl) - inverse hyperbolic tangent function - [atanl](https://manual.cs50.io/3/atanl) - arc tangent function - [cbrt](https://manual.cs50.io/3/cbrt) - cube root function - [cbrtf](https://manual.cs50.io/3/cbrtf) - cube root function - [cbrtl](https://manual.cs50.io/3/cbrtl) - cube root function - [ceil](https://manual.cs50.io/3/ceil) - ceiling function: smallest integral value not less tha... calculate the ceiling of a number - [ceilf](https://manual.cs50.io/3/ceilf) - ceiling function: smallest integral value not less tha... - [ceill](https://manual.cs50.io/3/ceill) - ceiling function: smallest integral value not less tha... - [copysign](https://manual.cs50.io/3/copysign) - copy sign of a number - [copysignf](https://manual.cs50.io/3/copysignf) - copy sign of a number - [copysignl](https://manual.cs50.io/3/copysignl) - copy sign of a number - [cos](https://manual.cs50.io/3/cos) - cosine function - [cosf](https://manual.cs50.io/3/cosf) - cosine function - [cosh](https://manual.cs50.io/3/cosh) - hyperbolic cosine function - [coshf](https://manual.cs50.io/3/coshf) - hyperbolic cosine function - [coshl](https://manual.cs50.io/3/coshl) - hyperbolic cosine function - [cosl](https://manual.cs50.io/3/cosl) - cosine function - [drem](https://manual.cs50.io/3/drem) - floating-point remainder function - [dremf](https://manual.cs50.io/3/dremf) - floating-point remainder function - [dreml](https://manual.cs50.io/3/dreml) - floating-point remainder function - [erf](https://manual.cs50.io/3/erf) - error function - [erfc](https://manual.cs50.io/3/erfc) - complementary error function - [erfcf](https://manual.cs50.io/3/erfcf) - complementary error function - [erfcl](https://manual.cs50.io/3/erfcl) - complementary error function - [erff](https://manual.cs50.io/3/erff) - error function - [erfl](https://manual.cs50.io/3/erfl) - error function - [exp](https://manual.cs50.io/3/exp) - base-e exponential function - [exp10](https://manual.cs50.io/3/exp10) - base-10 exponential function - [exp10f](https://manual.cs50.io/3/exp10f) - base-10 exponential function - [exp10l](https://manual.cs50.io/3/exp10l) - base-10 exponential function - [exp2](https://manual.cs50.io/3/exp2) - base-2 exponential function - [exp2f](https://manual.cs50.io/3/exp2f) - base-2 exponential function - [exp2l](https://manual.cs50.io/3/exp2l) - base-2 exponential function - [expf](https://manual.cs50.io/3/expf) - base-e exponential function - [expl](https://manual.cs50.io/3/expl) - base-e exponential function - [expm1](https://manual.cs50.io/3/expm1) - exponential minus 1 - [expm1f](https://manual.cs50.io/3/expm1f) - exponential minus 1 - [expm1l](https://manual.cs50.io/3/expm1l) - exponential minus 1 - [fabs](https://manual.cs50.io/3/fabs) - absolute value of floating-point number - [fabsf](https://manual.cs50.io/3/fabsf) - absolute value of floating-point number - [fabsl](https://manual.cs50.io/3/fabsl) - absolute value of floating-point number - [fdim](https://manual.cs50.io/3/fdim) - positive difference - [fdimf](https://manual.cs50.io/3/fdimf) - positive difference - [fdiml](https://manual.cs50.io/3/fdiml) - positive difference - [finite](https://manual.cs50.io/3/finite) - BSD floating-point classification functions - [finitef](https://manual.cs50.io/3/finitef) - BSD floating-point classification functions - [finitel](https://manual.cs50.io/3/finitel) - BSD floating-point classification functions - [floor](https://manual.cs50.io/3/floor) - largest integral value not greater than argument calculate the floor of a number - [floorf](https://manual.cs50.io/3/floorf) - largest integral value not greater than argument - [floorl](https://manual.cs50.io/3/floorl) - largest integral value not greater than argument - [fma](https://manual.cs50.io/3/fma) - floating-point multiply and add - [fmaf](https://manual.cs50.io/3/fmaf) - floating-point multiply and add - [fmal](https://manual.cs50.io/3/fmal) - floating-point multiply and add - [fmax](https://manual.cs50.io/3/fmax) - determine maximum of two floating-point numbers - [fmaxf](https://manual.cs50.io/3/fmaxf) - determine maximum of two floating-point numbers - [fmaxl](https://manual.cs50.io/3/fmaxl) - determine maximum of two floating-point numbers - [fmin](https://manual.cs50.io/3/fmin) - determine minimum of two floating-point numbers - [fminf](https://manual.cs50.io/3/fminf) - determine minimum of two floating-point numbers - [fminl](https://manual.cs50.io/3/fminl) - determine minimum of two floating-point numbers - [fmod](https://manual.cs50.io/3/fmod) - floating-point remainder function - [fmodf](https://manual.cs50.io/3/fmodf) - floating-point remainder function - [fmodl](https://manual.cs50.io/3/fmodl) - floating-point remainder function - [fpclassify](https://manual.cs50.io/3/fpclassify) - floating-point classification macros - [frexp](https://manual.cs50.io/3/frexp) - convert floating-point number to fractional and integr... - [frexpf](https://manual.cs50.io/3/frexpf) - convert floating-point number to fractional and integr... - [frexpl](https://manual.cs50.io/3/frexpl) - convert floating-point number to fractional and integr... - [gamma](https://manual.cs50.io/3/gamma) - (logarithm of the) gamma function - [gammaf](https://manual.cs50.io/3/gammaf) - (logarithm of the) gamma function - [gammal](https://manual.cs50.io/3/gammal) - (logarithm of the) gamma function - [HUGE\_VAL](https://manual.cs50.io/3/HUGE_VAL) - floating-point constants - [HUGE\_VALF](https://manual.cs50.io/3/HUGE_VALF) - floating-point constants - [HUGE\_VALL](https://manual.cs50.io/3/HUGE_VALL) - floating-point constants - [hypot](https://manual.cs50.io/3/hypot) - Euclidean distance function - [hypotf](https://manual.cs50.io/3/hypotf) - Euclidean distance function - [hypotl](https://manual.cs50.io/3/hypotl) - Euclidean distance function - [ilogb](https://manual.cs50.io/3/ilogb) - get integer exponent of a floating-point value - [ilogbf](https://manual.cs50.io/3/ilogbf) - get integer exponent of a floating-point value - [ilogbl](https://manual.cs50.io/3/ilogbl) - get integer exponent of a floating-point value - [INFINITY](https://manual.cs50.io/3/INFINITY) - floating-point constants - [isfinite](https://manual.cs50.io/3/isfinite) - floating-point classification macros - [isgreater](https://manual.cs50.io/3/isgreater) - floating-point relational tests without exception for NaN - [isgreaterequal](https://manual.cs50.io/3/isgreaterequal) - floating-point relational tests without exception for NaN - [isinf](https://manual.cs50.io/3/isinf) - floating-point classification macros - [isinff](https://manual.cs50.io/3/isinff) - BSD floating-point classification functions - [isinfl](https://manual.cs50.io/3/isinfl) - BSD floating-point classification functions - [isless](https://manual.cs50.io/3/isless) - floating-point relational tests without exception for NaN - [islessequal](https://manual.cs50.io/3/islessequal) - floating-point relational tests without exception for NaN - [islessgreater](https://manual.cs50.io/3/islessgreater) - floating-point relational tests without exception for NaN - [isnan](https://manual.cs50.io/3/isnan) - floating-point classification macros - [isnanf](https://manual.cs50.io/3/isnanf) - BSD floating-point classification functions - [isnanl](https://manual.cs50.io/3/isnanl) - BSD floating-point classification functions - [isnormal](https://manual.cs50.io/3/isnormal) - floating-point classification macros - [isunordered](https://manual.cs50.io/3/isunordered) - floating-point relational tests without exception for NaN - [j0](https://manual.cs50.io/3/j0) - Bessel functions of the first kind - [j0f](https://manual.cs50.io/3/j0f) - Bessel functions of the first kind - [j0l](https://manual.cs50.io/3/j0l) - Bessel functions of the first kind - [j1](https://manual.cs50.io/3/j1) - Bessel functions of the first kind - [j1f](https://manual.cs50.io/3/j1f) - Bessel functions of the first kind - [j1l](https://manual.cs50.io/3/j1l) - Bessel functions of the first kind - [jn](https://manual.cs50.io/3/jn) - Bessel functions of the first kind - [jnf](https://manual.cs50.io/3/jnf) - Bessel functions of the first kind - [jnl](https://manual.cs50.io/3/jnl) - Bessel functions of the first kind - [ldexp](https://manual.cs50.io/3/ldexp) - multiply floating-point number by integral power of 2 - [ldexpf](https://manual.cs50.io/3/ldexpf) - multiply floating-point number by integral power of 2 - [ldexpl](https://manual.cs50.io/3/ldexpl) - multiply floating-point number by integral power of 2 - [lgamma](https://manual.cs50.io/3/lgamma) - log gamma function - [lgamma\_r](https://manual.cs50.io/3/lgamma_r) - log gamma function - [lgammaf](https://manual.cs50.io/3/lgammaf) - log gamma function - [lgammaf\_r](https://manual.cs50.io/3/lgammaf_r) - log gamma function - [lgammal](https://manual.cs50.io/3/lgammal) - log gamma function - [lgammal\_r](https://manual.cs50.io/3/lgammal_r) - log gamma function - [llrint](https://manual.cs50.io/3/llrint) - round to nearest integer - [llrintf](https://manual.cs50.io/3/llrintf) - round to nearest integer - [llrintl](https://manual.cs50.io/3/llrintl) - round to nearest integer - [llround](https://manual.cs50.io/3/llround) - round to nearest integer - [llroundf](https://manual.cs50.io/3/llroundf) - round to nearest integer - [llroundl](https://manual.cs50.io/3/llroundl) - round to nearest integer - [log](https://manual.cs50.io/3/log) - natural logarithmic function - [log10](https://manual.cs50.io/3/log10) - base-10 logarithmic function - [log10f](https://manual.cs50.io/3/log10f) - base-10 logarithmic function - [log10l](https://manual.cs50.io/3/log10l) - base-10 logarithmic function - [log1p](https://manual.cs50.io/3/log1p) - logarithm of 1 plus argument - [log1pf](https://manual.cs50.io/3/log1pf) - logarithm of 1 plus argument - [log1pl](https://manual.cs50.io/3/log1pl) - logarithm of 1 plus argument - [log2](https://manual.cs50.io/3/log2) - base-2 logarithmic function calculate the base-2 logarithm of a number - [log2f](https://manual.cs50.io/3/log2f) - base-2 logarithmic function - [log2l](https://manual.cs50.io/3/log2l) - base-2 logarithmic function - [logb](https://manual.cs50.io/3/logb) - get exponent of a floating-point value - [logbf](https://manual.cs50.io/3/logbf) - get exponent of a floating-point value - [logbl](https://manual.cs50.io/3/logbl) - get exponent of a floating-point value - [logf](https://manual.cs50.io/3/logf) - natural logarithmic function - [logl](https://manual.cs50.io/3/logl) - natural logarithmic function - [lrint](https://manual.cs50.io/3/lrint) - round to nearest integer - [lrintf](https://manual.cs50.io/3/lrintf) - round to nearest integer - [lrintl](https://manual.cs50.io/3/lrintl) - round to nearest integer - [lround](https://manual.cs50.io/3/lround) - round to nearest integer - [lroundf](https://manual.cs50.io/3/lroundf) - round to nearest integer - [lroundl](https://manual.cs50.io/3/lroundl) - round to nearest integer - [math\_error](https://manual.cs50.io/7/math_error) - detecting errors from mathematical functions - [matherr](https://manual.cs50.io/3/matherr) - SVID math library exception handling - [modf](https://manual.cs50.io/3/modf) - extract signed integral and fractional values from flo... - [modff](https://manual.cs50.io/3/modff) - extract signed integral and fractional values from flo... - [modfl](https://manual.cs50.io/3/modfl) - extract signed integral and fractional values from flo... - [NAN](https://manual.cs50.io/3/NAN) - floating-point constants - [nan](https://manual.cs50.io/3/nan) - return 'Not a Number' - [nanf](https://manual.cs50.io/3/nanf) - return 'Not a Number' - [nanl](https://manual.cs50.io/3/nanl) - return 'Not a Number' - [nearbyint](https://manual.cs50.io/3/nearbyint) - round to nearest integer - [nearbyintf](https://manual.cs50.io/3/nearbyintf) - round to nearest integer - [nearbyintl](https://manual.cs50.io/3/nearbyintl) - round to nearest integer - [nextafter](https://manual.cs50.io/3/nextafter) - floating-point number manipulation - [nextafterf](https://manual.cs50.io/3/nextafterf) - floating-point number manipulation - [nextafterl](https://manual.cs50.io/3/nextafterl) - floating-point number manipulation - [nextdown](https://manual.cs50.io/3/nextdown) - return next floating-point number toward positive/nega... - [nextdownf](https://manual.cs50.io/3/nextdownf) - return next floating-point number toward positive/nega... - [nextdownl](https://manual.cs50.io/3/nextdownl) - return next floating-point number toward positive/nega... - [nexttoward](https://manual.cs50.io/3/nexttoward) - floating-point number manipulation - [nexttowardf](https://manual.cs50.io/3/nexttowardf) - floating-point number manipulation - [nexttowardl](https://manual.cs50.io/3/nexttowardl) - floating-point number manipulation - [nextup](https://manual.cs50.io/3/nextup) - return next floating-point number toward positive/nega... - [nextupf](https://manual.cs50.io/3/nextupf) - return next floating-point number toward positive/nega... - [nextupl](https://manual.cs50.io/3/nextupl) - return next floating-point number toward positive/nega... - [pow](https://manual.cs50.io/3/pow) - power functions raise a number to a power - [pow10](https://manual.cs50.io/3/pow10) - base-10 power functions - [pow10f](https://manual.cs50.io/3/pow10f) - base-10 power functions - [pow10l](https://manual.cs50.io/3/pow10l) - base-10 power functions - [powf](https://manual.cs50.io/3/powf) - power functions - [powl](https://manual.cs50.io/3/powl) - power functions - [remainder](https://manual.cs50.io/3/remainder) - floating-point remainder function - [remainderf](https://manual.cs50.io/3/remainderf) - floating-point remainder function - [remainderl](https://manual.cs50.io/3/remainderl) - floating-point remainder function - [remquo](https://manual.cs50.io/3/remquo) - remainder and part of quotient - [remquof](https://manual.cs50.io/3/remquof) - remainder and part of quotient - [remquol](https://manual.cs50.io/3/remquol) - remainder and part of quotient - [rint](https://manual.cs50.io/3/rint) - round to nearest integer - [rintf](https://manual.cs50.io/3/rintf) - round to nearest integer - [rintl](https://manual.cs50.io/3/rintl) - round to nearest integer - [round](https://manual.cs50.io/3/round) - round to nearest integer, away from zero round a number to the nearest integer - [roundf](https://manual.cs50.io/3/roundf) - round to nearest integer, away from zero - [roundl](https://manual.cs50.io/3/roundl) - round to nearest integer, away from zero - [scalb](https://manual.cs50.io/3/scalb) - multiply floating-point number by integral power of ra... - [scalbf](https://manual.cs50.io/3/scalbf) - multiply floating-point number by integral power of ra... - [scalbl](https://manual.cs50.io/3/scalbl) - multiply floating-point number by integral power of ra... - [scalbln](https://manual.cs50.io/3/scalbln) - multiply floating-point number by integral power of radix - [scalblnf](https://manual.cs50.io/3/scalblnf) - multiply floating-point number by integral power of radix - [scalblnl](https://manual.cs50.io/3/scalblnl) - multiply floating-point number by integral power of radix - [scalbn](https://manual.cs50.io/3/scalbn) - multiply floating-point number by integral power of radix - [scalbnf](https://manual.cs50.io/3/scalbnf) - multiply floating-point number by integral power of radix - [scalbnl](https://manual.cs50.io/3/scalbnl) - multiply floating-point number by integral power of radix - [signbit](https://manual.cs50.io/3/signbit) - test sign of a real floating-point number - [signgam](https://manual.cs50.io/3/signgam) - log gamma function - [significand](https://manual.cs50.io/3/significand) - get mantissa of floating-point number - [significandf](https://manual.cs50.io/3/significandf) - get mantissa of floating-point number - [significandl](https://manual.cs50.io/3/significandl) - get mantissa of floating-point number - [sin](https://manual.cs50.io/3/sin) - sine function - [sincos](https://manual.cs50.io/3/sincos) - calculate sin and cos simultaneously - [sincosf](https://manual.cs50.io/3/sincosf) - calculate sin and cos simultaneously - [sincosl](https://manual.cs50.io/3/sincosl) - calculate sin and cos simultaneously - [sinf](https://manual.cs50.io/3/sinf) - sine function - [sinh](https://manual.cs50.io/3/sinh) - hyperbolic sine function - [sinhf](https://manual.cs50.io/3/sinhf) - hyperbolic sine function - [sinhl](https://manual.cs50.io/3/sinhl) - hyperbolic sine function - [sinl](https://manual.cs50.io/3/sinl) - sine function - [sqrt](https://manual.cs50.io/3/sqrt) - square root function calculate the square root of a number - [sqrtf](https://manual.cs50.io/3/sqrtf) - square root function - [sqrtl](https://manual.cs50.io/3/sqrtl) - square root function - [tan](https://manual.cs50.io/3/tan) - tangent function - [tanf](https://manual.cs50.io/3/tanf) - tangent function - [tanh](https://manual.cs50.io/3/tanh) - hyperbolic tangent function - [tanhf](https://manual.cs50.io/3/tanhf) - hyperbolic tangent function - [tanhl](https://manual.cs50.io/3/tanhl) - hyperbolic tangent function - [tanl](https://manual.cs50.io/3/tanl) - tangent function - [tgamma](https://manual.cs50.io/3/tgamma) - true gamma function - [tgammaf](https://manual.cs50.io/3/tgammaf) - true gamma function - [tgammal](https://manual.cs50.io/3/tgammal) - true gamma function - [trunc](https://manual.cs50.io/3/trunc) - round to integer, toward zero - [truncf](https://manual.cs50.io/3/truncf) - round to integer, toward zero - [truncl](https://manual.cs50.io/3/truncl) - round to integer, toward zero - [y0](https://manual.cs50.io/3/y0) - Bessel functions of the second kind - [y0f](https://manual.cs50.io/3/y0f) - Bessel functions of the second kind - [y0l](https://manual.cs50.io/3/y0l) - Bessel functions of the second kind - [y1](https://manual.cs50.io/3/y1) - Bessel functions of the second kind - [y1f](https://manual.cs50.io/3/y1f) - Bessel functions of the second kind - [y1l](https://manual.cs50.io/3/y1l) - Bessel functions of the second kind - [yn](https://manual.cs50.io/3/yn) - Bessel functions of the second kind - [ynf](https://manual.cs50.io/3/ynf) - Bessel functions of the second kind - [ynl](https://manual.cs50.io/3/ynl) - Bessel functions of the second kind ## [monetary.h](https://manual.cs50.io/#monetary.h) - [strfmon](https://manual.cs50.io/3/strfmon) - convert monetary value to a string - [strfmon\_l](https://manual.cs50.io/3/strfmon_l) - convert monetary value to a string ## [mqueue.h](https://manual.cs50.io/#mqueue.h) - [mq\_close](https://manual.cs50.io/3/mq_close) - close a message queue descriptor - [mq\_getattr](https://manual.cs50.io/3/mq_getattr) - get/set message queue attributes - [mq\_notify](https://manual.cs50.io/2/mq_notify) - register for notification when a message is available - [mq\_notify](https://manual.cs50.io/3/mq_notify) - register for notification when a message is available - [mq\_open](https://manual.cs50.io/2/mq_open) - open a message queue - [mq\_open](https://manual.cs50.io/3/mq_open) - open a message queue - [mq\_receive](https://manual.cs50.io/3/mq_receive) - receive a message from a message queue - [mq\_send](https://manual.cs50.io/3/mq_send) - send a message to a message queue - [mq\_setattr](https://manual.cs50.io/3/mq_setattr) - get/set message queue attributes - [mq\_timedreceive](https://manual.cs50.io/2/mq_timedreceive) - receive a message from a message queue - [mq\_timedreceive](https://manual.cs50.io/3/mq_timedreceive) - receive a message from a message queue - [mq\_timedsend](https://manual.cs50.io/2/mq_timedsend) - send a message to a message queue - [mq\_timedsend](https://manual.cs50.io/3/mq_timedsend) - send a message to a message queue - [mq\_unlink](https://manual.cs50.io/2/mq_unlink) - remove a message queue - [mq\_unlink](https://manual.cs50.io/3/mq_unlink) - remove a message queue ## [net/if.h](https://manual.cs50.io/#net/if.h) - [if\_freenameindex](https://manual.cs50.io/3/if_freenameindex) - get network interface names and indexes - [if\_indextoname](https://manual.cs50.io/3/if_indextoname) - mappings between network interface names and indexes - [if\_nameindex](https://manual.cs50.io/3/if_nameindex) - get network interface names and indexes - [if\_nametoindex](https://manual.cs50.io/3/if_nametoindex) - mappings between network interface names and indexes ## [netdb.h](https://manual.cs50.io/#netdb.h) - [endhostent](https://manual.cs50.io/3/endhostent) - get network host entry - [endnetent](https://manual.cs50.io/3/endnetent) - get network entry - [endnetgrent](https://manual.cs50.io/3/endnetgrent) - handle network group entries - [endprotoent](https://manual.cs50.io/3/endprotoent) - get protocol entry - [endrpcent](https://manual.cs50.io/3/endrpcent) - get RPC entry - [endservent](https://manual.cs50.io/3/endservent) - get service entry - [gai\_cancel](https://manual.cs50.io/3/gai_cancel) - asynchronous network address and service translation - [gai\_error](https://manual.cs50.io/3/gai_error) - asynchronous network address and service translation - [gai\_suspend](https://manual.cs50.io/3/gai_suspend) - asynchronous network address and service translation - [getaddrinfo\_a](https://manual.cs50.io/3/getaddrinfo_a) - asynchronous network address and service translation - [gethostbyaddr](https://manual.cs50.io/3/gethostbyaddr) - get network host entry - [gethostbyaddr\_r](https://manual.cs50.io/3/gethostbyaddr_r) - get network host entry - [gethostbyname](https://manual.cs50.io/3/gethostbyname) - get network host entry - [gethostbyname2](https://manual.cs50.io/3/gethostbyname2) - get network host entry - [gethostbyname2\_r](https://manual.cs50.io/3/gethostbyname2_r) - get network host entry - [gethostbyname\_r](https://manual.cs50.io/3/gethostbyname_r) - get network host entry - [gethostent](https://manual.cs50.io/3/gethostent) - get network host entry - [gethostent\_r](https://manual.cs50.io/3/gethostent_r) - get network host entry - [getnetbyaddr](https://manual.cs50.io/3/getnetbyaddr) - get network entry - [getnetbyaddr\_r](https://manual.cs50.io/3/getnetbyaddr_r) - get network entry (reentrant) - [getnetbyname](https://manual.cs50.io/3/getnetbyname) - get network entry - [getnetbyname\_r](https://manual.cs50.io/3/getnetbyname_r) - get network entry (reentrant) - [getnetent](https://manual.cs50.io/3/getnetent) - get network entry - [getnetent\_r](https://manual.cs50.io/3/getnetent_r) - get network entry (reentrant) - [getnetgrent](https://manual.cs50.io/3/getnetgrent) - handle network group entries - [getnetgrent\_r](https://manual.cs50.io/3/getnetgrent_r) - handle network group entries - [getprotobyname](https://manual.cs50.io/3/getprotobyname) - get protocol entry - [getprotobyname\_r](https://manual.cs50.io/3/getprotobyname_r) - get protocol entry (reentrant) - [getprotobynumber](https://manual.cs50.io/3/getprotobynumber) - get protocol entry - [getprotobynumber\_r](https://manual.cs50.io/3/getprotobynumber_r) - get protocol entry (reentrant) - [getprotoent](https://manual.cs50.io/3/getprotoent) - get protocol entry - [getprotoent\_r](https://manual.cs50.io/3/getprotoent_r) - get protocol entry (reentrant) - [getrpcbyname](https://manual.cs50.io/3/getrpcbyname) - get RPC entry - [getrpcbyname\_r](https://manual.cs50.io/3/getrpcbyname_r) - get RPC entry (reentrant) - [getrpcbynumber](https://manual.cs50.io/3/getrpcbynumber) - get RPC entry - [getrpcbynumber\_r](https://manual.cs50.io/3/getrpcbynumber_r) - get RPC entry (reentrant) - [getrpcent](https://manual.cs50.io/3/getrpcent) - get RPC entry - [getrpcent\_r](https://manual.cs50.io/3/getrpcent_r) - get RPC entry (reentrant) - [getservbyname](https://manual.cs50.io/3/getservbyname) - get service entry - [getservbyname\_r](https://manual.cs50.io/3/getservbyname_r) - get service entry (reentrant) - [getservbyport](https://manual.cs50.io/3/getservbyport) - get service entry - [getservbyport\_r](https://manual.cs50.io/3/getservbyport_r) - get service entry (reentrant) - [getservent](https://manual.cs50.io/3/getservent) - get service entry - [getservent\_r](https://manual.cs50.io/3/getservent_r) - get service entry (reentrant) - [h\_errno](https://manual.cs50.io/3/h_errno) - get network host entry - [herror](https://manual.cs50.io/3/herror) - get network host entry - [hstrerror](https://manual.cs50.io/3/hstrerror) - get network host entry - [innetgr](https://manual.cs50.io/3/innetgr) - handle network group entries - [rexec](https://manual.cs50.io/3/rexec) - return stream to a remote command - [rexec\_af](https://manual.cs50.io/3/rexec_af) - return stream to a remote command - [sethostent](https://manual.cs50.io/3/sethostent) - get network host entry - [setnetent](https://manual.cs50.io/3/setnetent) - get network entry - [setnetgrent](https://manual.cs50.io/3/setnetgrent) - handle network group entries - [setprotoent](https://manual.cs50.io/3/setprotoent) - get protocol entry - [setrpcent](https://manual.cs50.io/3/setrpcent) - get RPC entry - [setservent](https://manual.cs50.io/3/setservent) - get service entry ## [netinet/in.h](https://manual.cs50.io/#netinet/in.h) - [dn\_comp](https://manual.cs50.io/3/dn_comp) - resolver routines - [dn\_expand](https://manual.cs50.io/3/dn_expand) - resolver routines - [res\_init](https://manual.cs50.io/3/res_init) - resolver routines - [res\_mkquery](https://manual.cs50.io/3/res_mkquery) - resolver routines - [res\_nclose](https://manual.cs50.io/3/res_nclose) - resolver routines - [res\_ninit](https://manual.cs50.io/3/res_ninit) - resolver routines - [res\_nmkquery](https://manual.cs50.io/3/res_nmkquery) - resolver routines - [res\_nquery](https://manual.cs50.io/3/res_nquery) - resolver routines - [res\_nquerydomain](https://manual.cs50.io/3/res_nquerydomain) - resolver routines - [res\_nsearch](https://manual.cs50.io/3/res_nsearch) - resolver routines - [res\_nsend](https://manual.cs50.io/3/res_nsend) - resolver routines - [res\_query](https://manual.cs50.io/3/res_query) - resolver routines - [res\_querydomain](https://manual.cs50.io/3/res_querydomain) - resolver routines - [res\_search](https://manual.cs50.io/3/res_search) - resolver routines - [res\_send](https://manual.cs50.io/3/res_send) - resolver routines - [resolver](https://manual.cs50.io/3/resolver) - resolver routines ## [nl\_types.h](https://manual.cs50.io/#nl_types.h) - [catclose](https://manual.cs50.io/3/catclose) - open/close a message catalog - [catgets](https://manual.cs50.io/3/catgets) - get message from a message catalog - [catopen](https://manual.cs50.io/3/catopen) - open/close a message catalog ## [poll.h](https://manual.cs50.io/#poll.h) - [poll](https://manual.cs50.io/2/poll) - wait for some event on a file descriptor - [ppoll](https://manual.cs50.io/2/ppoll) - wait for some event on a file descriptor ## [pthread.h](https://manual.cs50.io/#pthread.h) - [pthread\_attr\_destroy](https://manual.cs50.io/3/pthread_attr_destroy) - initialize and destroy thread attributes object - [pthread\_attr\_getaffinity\_np](https://manual.cs50.io/3/pthread_attr_getaffinity_np) - set/get CPU affinity attribute in thread at... - [pthread\_attr\_getdetachstate](https://manual.cs50.io/3/pthread_attr_getdetachstate) - set/get detach state attribute in thread at... - [pthread\_attr\_getguardsize](https://manual.cs50.io/3/pthread_attr_getguardsize) - set/get guard size attribute in thread attrib... - [pthread\_attr\_getinheritsched](https://manual.cs50.io/3/pthread_attr_getinheritsched) - set/get inherit-scheduler attribute in thr... - [pthread\_attr\_getschedparam](https://manual.cs50.io/3/pthread_attr_getschedparam) - set/get scheduling parameter attributes in t... - [pthread\_attr\_getschedpolicy](https://manual.cs50.io/3/pthread_attr_getschedpolicy) - set/get scheduling policy attribute in thre... - [pthread\_attr\_getscope](https://manual.cs50.io/3/pthread_attr_getscope) - set/get contention scope attribute in thread attr... - [pthread\_attr\_getsigmask\_np](https://manual.cs50.io/3/pthread_attr_getsigmask_np) - set/get signal mask attribute in thread attr... - [pthread\_attr\_getstack](https://manual.cs50.io/3/pthread_attr_getstack) - set/get stack attributes in thread attributes object - [pthread\_attr\_getstackaddr](https://manual.cs50.io/3/pthread_attr_getstackaddr) - set/get stack address attribute in thread att... - [pthread\_attr\_getstacksize](https://manual.cs50.io/3/pthread_attr_getstacksize) - set/get stack size attribute in thread attrib... - [pthread\_attr\_init](https://manual.cs50.io/3/pthread_attr_init) - initialize and destroy thread attributes object - [pthread\_attr\_setaffinity\_np](https://manual.cs50.io/3/pthread_attr_setaffinity_np) - set/get CPU affinity attribute in thread at... - [pthread\_attr\_setdetachstate](https://manual.cs50.io/3/pthread_attr_setdetachstate) - set/get detach state attribute in thread at... - [pthread\_attr\_setguardsize](https://manual.cs50.io/3/pthread_attr_setguardsize) - set/get guard size attribute in thread attrib... - [pthread\_attr\_setinheritsched](https://manual.cs50.io/3/pthread_attr_setinheritsched) - set/get inherit-scheduler attribute in thr... - [pthread\_attr\_setschedparam](https://manual.cs50.io/3/pthread_attr_setschedparam) - set/get scheduling parameter attributes in t... - [pthread\_attr\_setschedpolicy](https://manual.cs50.io/3/pthread_attr_setschedpolicy) - set/get scheduling policy attribute in thre... - [pthread\_attr\_setscope](https://manual.cs50.io/3/pthread_attr_setscope) - set/get contention scope attribute in thread attr... - [pthread\_attr\_setsigmask\_np](https://manual.cs50.io/3/pthread_attr_setsigmask_np) - set/get signal mask attribute in thread attr... - [pthread\_attr\_setstack](https://manual.cs50.io/3/pthread_attr_setstack) - set/get stack attributes in thread attributes object - [pthread\_attr\_setstackaddr](https://manual.cs50.io/3/pthread_attr_setstackaddr) - set/get stack address attribute in thread att... - [pthread\_attr\_setstacksize](https://manual.cs50.io/3/pthread_attr_setstacksize) - set/get stack size attribute in thread attrib... - [pthread\_cancel](https://manual.cs50.io/3/pthread_cancel) - send a cancelation request to a thread - [pthread\_cleanup\_pop](https://manual.cs50.io/3/pthread_cleanup_pop) - push and pop thread cancelation clean-up handlers - [pthread\_cleanup\_pop\_restore\_np](https://manual.cs50.io/3/pthread_cleanup_pop_restore_np) - push and pop thread cancelation clean-up... - [pthread\_cleanup\_push](https://manual.cs50.io/3/pthread_cleanup_push) - push and pop thread cancelation clean-up handlers - [pthread\_cleanup\_push\_defer\_np](https://manual.cs50.io/3/pthread_cleanup_push_defer_np) - push and pop thread cancelation clean-up ... - [pthread\_create](https://manual.cs50.io/3/pthread_create) - create a new thread - [pthread\_detach](https://manual.cs50.io/3/pthread_detach) - detach a thread - [pthread\_equal](https://manual.cs50.io/3/pthread_equal) - compare thread IDs - [pthread\_exit](https://manual.cs50.io/3/pthread_exit) - terminate calling thread - [pthread\_getaffinity\_np](https://manual.cs50.io/3/pthread_getaffinity_np) - set/get CPU affinity of a thread - [pthread\_getattr\_default\_np](https://manual.cs50.io/3/pthread_getattr_default_np) - get or set default thread-creation attributes - [pthread\_getattr\_np](https://manual.cs50.io/3/pthread_getattr_np) - get attributes of created thread - [pthread\_getconcurrency](https://manual.cs50.io/3/pthread_getconcurrency) - set/get the concurrency level - [pthread\_getcpuclockid](https://manual.cs50.io/3/pthread_getcpuclockid) - retrieve ID of a thread's CPU time clock - [pthread\_getname\_np](https://manual.cs50.io/3/pthread_getname_np) - set/get the name of a thread - [pthread\_getschedparam](https://manual.cs50.io/3/pthread_getschedparam) - set/get scheduling policy and parameters of a thread - [pthread\_join](https://manual.cs50.io/3/pthread_join) - join with a terminated thread - [pthread\_kill\_other\_threads\_np](https://manual.cs50.io/3/pthread_kill_other_threads_np) - terminate all other threads in process - [pthread\_mutex\_consistent](https://manual.cs50.io/3/pthread_mutex_consistent) - make a robust mutex consistent - [pthread\_mutex\_consistent\_np](https://manual.cs50.io/3/pthread_mutex_consistent_np) - make a robust mutex consistent - [pthread\_mutexattr\_getpshared](https://manual.cs50.io/3/pthread_mutexattr_getpshared) - get/set process-shared mutex attribute - [pthread\_mutexattr\_getrobust](https://manual.cs50.io/3/pthread_mutexattr_getrobust) - get and set the robustness attribute of a m... - [pthread\_mutexattr\_getrobust\_np](https://manual.cs50.io/3/pthread_mutexattr_getrobust_np) - get and set the robustness attribute of ... - [pthread\_mutexattr\_setpshared](https://manual.cs50.io/3/pthread_mutexattr_setpshared) - get/set process-shared mutex attribute - [pthread\_mutexattr\_setrobust](https://manual.cs50.io/3/pthread_mutexattr_setrobust) - get and set the robustness attribute of a m... - [pthread\_mutexattr\_setrobust\_np](https://manual.cs50.io/3/pthread_mutexattr_setrobust_np) - get and set the robustness attribute of ... - [pthread\_rwlockattr\_getkind\_np](https://manual.cs50.io/3/pthread_rwlockattr_getkind_np) - set/get the read-write lock kind of the t... - [pthread\_rwlockattr\_setkind\_np](https://manual.cs50.io/3/pthread_rwlockattr_setkind_np) - set/get the read-write lock kind of the t... - [pthread\_self](https://manual.cs50.io/3/pthread_self) - obtain ID of the calling thread - [pthread\_setaffinity\_np](https://manual.cs50.io/3/pthread_setaffinity_np) - set/get CPU affinity of a thread - [pthread\_setattr\_default\_np](https://manual.cs50.io/3/pthread_setattr_default_np) - get or set default thread-creation attributes - [pthread\_setcancelstate](https://manual.cs50.io/3/pthread_setcancelstate) - set cancelability state and type - [pthread\_setcanceltype](https://manual.cs50.io/3/pthread_setcanceltype) - set cancelability state and type - [pthread\_setconcurrency](https://manual.cs50.io/3/pthread_setconcurrency) - set/get the concurrency level - [pthread\_setname\_np](https://manual.cs50.io/3/pthread_setname_np) - set/get the name of a thread - [pthread\_setschedparam](https://manual.cs50.io/3/pthread_setschedparam) - set/get scheduling policy and parameters of a thread - [pthread\_setschedprio](https://manual.cs50.io/3/pthread_setschedprio) - set scheduling priority of a thread - [pthread\_spin\_destroy](https://manual.cs50.io/3/pthread_spin_destroy) - initialize or destroy a spin lock - [pthread\_spin\_init](https://manual.cs50.io/3/pthread_spin_init) - initialize or destroy a spin lock - [pthread\_spin\_lock](https://manual.cs50.io/3/pthread_spin_lock) - lock and unlock a spin lock - [pthread\_spin\_trylock](https://manual.cs50.io/3/pthread_spin_trylock) - lock and unlock a spin lock - [pthread\_spin\_unlock](https://manual.cs50.io/3/pthread_spin_unlock) - lock and unlock a spin lock - [pthread\_testcancel](https://manual.cs50.io/3/pthread_testcancel) - request delivery of any pending cancelation request - [pthread\_timedjoin\_np](https://manual.cs50.io/3/pthread_timedjoin_np) - try to join with a terminated thread - [pthread\_tryjoin\_np](https://manual.cs50.io/3/pthread_tryjoin_np) - try to join with a terminated thread - [pthread\_yield](https://manual.cs50.io/3/pthread_yield) - yield the processor ## [pwd.h](https://manual.cs50.io/#pwd.h) - [fgetpwent\_r](https://manual.cs50.io/3/fgetpwent_r) - get passwd file entry reentrantly - [getpwent\_r](https://manual.cs50.io/3/getpwent_r) - get passwd file entry reentrantly ## [regex.h](https://manual.cs50.io/#regex.h) - [regcomp](https://manual.cs50.io/3/regcomp) - POSIX regex functions - [regerror](https://manual.cs50.io/3/regerror) - POSIX regex functions - [regex](https://manual.cs50.io/3/regex) - POSIX regex functions - [regexec](https://manual.cs50.io/3/regexec) - POSIX regex functions - [regfree](https://manual.cs50.io/3/regfree) - POSIX regex functions ## [sched.h](https://manual.cs50.io/#sched.h) - [\_\_clone2](https://manual.cs50.io/2/__clone2) - create a child process - [clone](https://manual.cs50.io/2/clone) - create a child process - [clone2](https://manual.cs50.io/2/clone2) - create a child process - [clone3](https://manual.cs50.io/2/clone3) - create a child process - [CPU\_ALLOC](https://manual.cs50.io/3/CPU_ALLOC) - macros for manipulating CPU sets - [CPU\_ALLOC\_SIZE](https://manual.cs50.io/3/CPU_ALLOC_SIZE) - macros for manipulating CPU sets - [CPU\_AND](https://manual.cs50.io/3/CPU_AND) - macros for manipulating CPU sets - [CPU\_AND\_S](https://manual.cs50.io/3/CPU_AND_S) - macros for manipulating CPU sets - [CPU\_CLR](https://manual.cs50.io/3/CPU_CLR) - macros for manipulating CPU sets - [CPU\_CLR\_S](https://manual.cs50.io/3/CPU_CLR_S) - macros for manipulating CPU sets - [CPU\_COUNT](https://manual.cs50.io/3/CPU_COUNT) - macros for manipulating CPU sets - [CPU\_COUNT\_S](https://manual.cs50.io/3/CPU_COUNT_S) - macros for manipulating CPU sets - [CPU\_EQUAL](https://manual.cs50.io/3/CPU_EQUAL) - macros for manipulating CPU sets - [CPU\_EQUAL\_S](https://manual.cs50.io/3/CPU_EQUAL_S) - macros for manipulating CPU sets - [CPU\_FREE](https://manual.cs50.io/3/CPU_FREE) - macros for manipulating CPU sets - [CPU\_ISSET](https://manual.cs50.io/3/CPU_ISSET) - macros for manipulating CPU sets - [CPU\_ISSET\_S](https://manual.cs50.io/3/CPU_ISSET_S) - macros for manipulating CPU sets - [CPU\_OR](https://manual.cs50.io/3/CPU_OR) - macros for manipulating CPU sets - [CPU\_OR\_S](https://manual.cs50.io/3/CPU_OR_S) - macros for manipulating CPU sets - [CPU\_SET](https://manual.cs50.io/3/CPU_SET) - macros for manipulating CPU sets - [CPU\_SET\_S](https://manual.cs50.io/3/CPU_SET_S) - macros for manipulating CPU sets - [CPU\_XOR](https://manual.cs50.io/3/CPU_XOR) - macros for manipulating CPU sets - [CPU\_XOR\_S](https://manual.cs50.io/3/CPU_XOR_S) - macros for manipulating CPU sets - [CPU\_ZERO](https://manual.cs50.io/3/CPU_ZERO) - macros for manipulating CPU sets - [CPU\_ZERO\_S](https://manual.cs50.io/3/CPU_ZERO_S) - macros for manipulating CPU sets - [getcpu](https://manual.cs50.io/2/getcpu) - determine CPU and NUMA node on which the calling threa... - [sched\_get\_priority\_max](https://manual.cs50.io/2/sched_get_priority_max) - get static priority range - [sched\_get\_priority\_min](https://manual.cs50.io/2/sched_get_priority_min) - get static priority range - [sched\_getaffinity](https://manual.cs50.io/2/sched_getaffinity) - set and get a thread's CPU affinity mask - [sched\_getcpu](https://manual.cs50.io/3/sched_getcpu) - determine CPU on which the calling thread is running - [sched\_getparam](https://manual.cs50.io/2/sched_getparam) - set and get scheduling parameters - [sched\_getscheduler](https://manual.cs50.io/2/sched_getscheduler) - set and get scheduling policy/parameters - [sched\_rr\_get\_interval](https://manual.cs50.io/2/sched_rr_get_interval) - get the SCHED\_RR interval for the named process - [sched\_setaffinity](https://manual.cs50.io/2/sched_setaffinity) - set and get a thread's CPU affinity mask - [sched\_setparam](https://manual.cs50.io/2/sched_setparam) - set and get scheduling parameters - [sched\_setscheduler](https://manual.cs50.io/2/sched_setscheduler) - set and get scheduling policy/parameters - [sched\_yield](https://manual.cs50.io/2/sched_yield) - yield the processor - [setns](https://manual.cs50.io/2/setns) - reassociate thread with a namespace - [unshare](https://manual.cs50.io/2/unshare) - disassociate parts of the process execution context ## [search.h](https://manual.cs50.io/#search.h) - [hcreate](https://manual.cs50.io/3/hcreate) - hash table management - [hcreate\_r](https://manual.cs50.io/3/hcreate_r) - hash table management - [hdestroy](https://manual.cs50.io/3/hdestroy) - hash table management - [hdestroy\_r](https://manual.cs50.io/3/hdestroy_r) - hash table management - [hsearch](https://manual.cs50.io/3/hsearch) - hash table management - [hsearch\_r](https://manual.cs50.io/3/hsearch_r) - hash table management - [insque](https://manual.cs50.io/3/insque) - insert/remove an item from a queue - [lfind](https://manual.cs50.io/3/lfind) - linear search of an array - [lsearch](https://manual.cs50.io/3/lsearch) - linear search of an array - [remque](https://manual.cs50.io/3/remque) - insert/remove an item from a queue - [tdelete](https://manual.cs50.io/3/tdelete) - manage a binary search tree - [tdestroy](https://manual.cs50.io/3/tdestroy) - manage a binary search tree - [tfind](https://manual.cs50.io/3/tfind) - manage a binary search tree - [tsearch](https://manual.cs50.io/3/tsearch) - manage a binary search tree - [twalk](https://manual.cs50.io/3/twalk) - manage a binary search tree - [twalk\_r](https://manual.cs50.io/3/twalk_r) - manage a binary search tree ## [semaphore.h](https://manual.cs50.io/#semaphore.h) - [sem\_close](https://manual.cs50.io/3/sem_close) - close a named semaphore - [sem\_destroy](https://manual.cs50.io/3/sem_destroy) - destroy an unnamed semaphore - [sem\_getvalue](https://manual.cs50.io/3/sem_getvalue) - get the value of a semaphore - [sem\_init](https://manual.cs50.io/3/sem_init) - initialize an unnamed semaphore - [sem\_open](https://manual.cs50.io/3/sem_open) - initialize and open a named semaphore - [sem\_post](https://manual.cs50.io/3/sem_post) - unlock a semaphore - [sem\_timedwait](https://manual.cs50.io/3/sem_timedwait) - lock a semaphore - [sem\_trywait](https://manual.cs50.io/3/sem_trywait) - lock a semaphore - [sem\_unlink](https://manual.cs50.io/3/sem_unlink) - remove a named semaphore - [sem\_wait](https://manual.cs50.io/3/sem_wait) - lock a semaphore ## [setjmp.h](https://manual.cs50.io/#setjmp.h) - [longjmp](https://manual.cs50.io/3/longjmp) - performing a nonlocal goto - [setjmp](https://manual.cs50.io/3/setjmp) - performing a nonlocal goto - [siglongjmp](https://manual.cs50.io/3/siglongjmp) - performing a nonlocal goto - [sigsetjmp](https://manual.cs50.io/3/sigsetjmp) - performing a nonlocal goto ## [signal.h](https://manual.cs50.io/#signal.h) - [bsd\_signal](https://manual.cs50.io/3/bsd_signal) - signal handling with BSD semantics - [gsignal](https://manual.cs50.io/3/gsignal) - software signal facility - [kill](https://manual.cs50.io/2/kill) - send signal to a process - [killpg](https://manual.cs50.io/3/killpg) - send signal to a process group - [psiginfo](https://manual.cs50.io/3/psiginfo) - print signal description - [psignal](https://manual.cs50.io/3/psignal) - print signal description - [pthread\_kill](https://manual.cs50.io/3/pthread_kill) - send a signal to a thread - [pthread\_sigmask](https://manual.cs50.io/3/pthread_sigmask) - examine and change mask of blocked signals - [pthread\_sigqueue](https://manual.cs50.io/3/pthread_sigqueue) - queue a signal and data to a thread - [raise](https://manual.cs50.io/3/raise) - send a signal to the caller - [rt\_sigaction](https://manual.cs50.io/2/rt_sigaction) - examine and change a signal action - [rt\_sigpending](https://manual.cs50.io/2/rt_sigpending) - examine pending signals - [rt\_sigprocmask](https://manual.cs50.io/2/rt_sigprocmask) - examine and change blocked signals - [rt\_sigsuspend](https://manual.cs50.io/2/rt_sigsuspend) - wait for a signal - [rt\_sigtimedwait](https://manual.cs50.io/2/rt_sigtimedwait) - synchronously wait for queued signals - [sigaction](https://manual.cs50.io/2/sigaction) - examine and change a signal action - [sigaddset](https://manual.cs50.io/3/sigaddset) - POSIX signal set operations - [sigaltstack](https://manual.cs50.io/2/sigaltstack) - set and/or get signal stack context - [sigandset](https://manual.cs50.io/3/sigandset) - POSIX signal set operations - [sigblock](https://manual.cs50.io/3/sigblock) - BSD signal API - [sigdelset](https://manual.cs50.io/3/sigdelset) - POSIX signal set operations - [sigemptyset](https://manual.cs50.io/3/sigemptyset) - POSIX signal set operations - [sigfillset](https://manual.cs50.io/3/sigfillset) - POSIX signal set operations - [siggetmask](https://manual.cs50.io/3/siggetmask) - BSD signal API - [sighold](https://manual.cs50.io/3/sighold) - System V signal API - [sigignore](https://manual.cs50.io/3/sigignore) - System V signal API - [siginterrupt](https://manual.cs50.io/3/siginterrupt) - allow signals to interrupt system calls - [sigisemptyset](https://manual.cs50.io/3/sigisemptyset) - POSIX signal set operations - [sigismember](https://manual.cs50.io/3/sigismember) - POSIX signal set operations - [sigmask](https://manual.cs50.io/3/sigmask) - BSD signal API - [signal](https://manual.cs50.io/2/signal) - ANSI C signal handling - [sigorset](https://manual.cs50.io/3/sigorset) - POSIX signal set operations - [sigpause](https://manual.cs50.io/3/sigpause) - atomically release blocked signals and wait for interrupt - [sigpending](https://manual.cs50.io/2/sigpending) - examine pending signals - [sigprocmask](https://manual.cs50.io/2/sigprocmask) - examine and change blocked signals - [sigqueue](https://manual.cs50.io/3/sigqueue) - queue a signal and data to a process - [sigrelse](https://manual.cs50.io/3/sigrelse) - System V signal API - [sigset](https://manual.cs50.io/3/sigset) - System V signal API - [sigsetmask](https://manual.cs50.io/3/sigsetmask) - BSD signal API - [sigsetops](https://manual.cs50.io/3/sigsetops) - POSIX signal set operations - [sigstack](https://manual.cs50.io/3/sigstack) - set and/or get signal stack context - [sigsuspend](https://manual.cs50.io/2/sigsuspend) - wait for a signal - [sigtimedwait](https://manual.cs50.io/2/sigtimedwait) - synchronously wait for queued signals - [sigvec](https://manual.cs50.io/3/sigvec) - BSD signal API - [sigwait](https://manual.cs50.io/3/sigwait) - wait for a signal - [sigwaitinfo](https://manual.cs50.io/2/sigwaitinfo) - synchronously wait for queued signals - [ssignal](https://manual.cs50.io/3/ssignal) - software signal facility - [sysv\_signal](https://manual.cs50.io/3/sysv_signal) - signal handling with System V semantics ## [spawn.h](https://manual.cs50.io/#spawn.h) - [posix\_spawn](https://manual.cs50.io/3/posix_spawn) - spawn a process - [posix\_spawnp](https://manual.cs50.io/3/posix_spawnp) - spawn a process ## [stdarg.h](https://manual.cs50.io/#stdarg.h) - [stdarg](https://manual.cs50.io/3/stdarg) - variable argument lists - [va\_arg](https://manual.cs50.io/3/va_arg) - variable argument lists - [va\_copy](https://manual.cs50.io/3/va_copy) - variable argument lists - [va\_end](https://manual.cs50.io/3/va_end) - variable argument lists - [va\_start](https://manual.cs50.io/3/va_start) - variable argument lists ## [stddef.h](https://manual.cs50.io/#stddef.h) - [offsetof](https://manual.cs50.io/3/offsetof) - offset of a structure member - [wcstoimax](https://manual.cs50.io/3/wcstoimax) - convert wide-character string to integer - [wcstoumax](https://manual.cs50.io/3/wcstoumax) - convert wide-character string to integer ## [stdio.h](https://manual.cs50.io/#stdio.h) - [\_\_fbufsize](https://manual.cs50.io/3/__fbufsize) - interfaces to stdio FILE structure - [\_\_flbf](https://manual.cs50.io/3/__flbf) - interfaces to stdio FILE structure - [\_\_fpending](https://manual.cs50.io/3/__fpending) - interfaces to stdio FILE structure - [\_\_fpurge](https://manual.cs50.io/3/__fpurge) - purge a stream - [\_\_freadable](https://manual.cs50.io/3/__freadable) - interfaces to stdio FILE structure - [\_\_freading](https://manual.cs50.io/3/__freading) - interfaces to stdio FILE structure - [\_\_fsetlocking](https://manual.cs50.io/3/__fsetlocking) - interfaces to stdio FILE structure - [\_\_fwritable](https://manual.cs50.io/3/__fwritable) - interfaces to stdio FILE structure - [\_\_fwriting](https://manual.cs50.io/3/__fwriting) - interfaces to stdio FILE structure - [\_flushlbf](https://manual.cs50.io/3/_flushlbf) - interfaces to stdio FILE structure - [addmntent](https://manual.cs50.io/3/addmntent) - get filesystem descriptor file entry - [asprintf](https://manual.cs50.io/3/asprintf) - print to allocated string - [clearerr](https://manual.cs50.io/3/clearerr) - check and reset stream status - [clearerr\_unlocked](https://manual.cs50.io/3/clearerr_unlocked) - nonlocking stdio functions - [ctermid](https://manual.cs50.io/3/ctermid) - get controlling terminal name - [dprintf](https://manual.cs50.io/3/dprintf) - formatted output conversion - [endmntent](https://manual.cs50.io/3/endmntent) - get filesystem descriptor file entry - [fclose](https://manual.cs50.io/3/fclose) - close a stream close a file - [fcloseall](https://manual.cs50.io/3/fcloseall) - close all open streams - [fdopen](https://manual.cs50.io/3/fdopen) - stream open functions - [feof](https://manual.cs50.io/3/feof) - check and reset stream status - [feof\_unlocked](https://manual.cs50.io/3/feof_unlocked) - nonlocking stdio functions - [ferror](https://manual.cs50.io/3/ferror) - check and reset stream status - [ferror\_unlocked](https://manual.cs50.io/3/ferror_unlocked) - nonlocking stdio functions - [fflush](https://manual.cs50.io/3/fflush) - flush a stream - [fflush\_unlocked](https://manual.cs50.io/3/fflush_unlocked) - nonlocking stdio functions - [fgetc](https://manual.cs50.io/3/fgetc) - input of characters and strings - [fgetc\_unlocked](https://manual.cs50.io/3/fgetc_unlocked) - nonlocking stdio functions - [fgetgrent](https://manual.cs50.io/3/fgetgrent) - get group file entry - [fgetpos](https://manual.cs50.io/3/fgetpos) - reposition a stream - [fgetpwent](https://manual.cs50.io/3/fgetpwent) - get password file entry - [fgets](https://manual.cs50.io/3/fgets) - input of characters and strings - [fgets\_unlocked](https://manual.cs50.io/3/fgets_unlocked) - nonlocking stdio functions - [fgetwc](https://manual.cs50.io/3/fgetwc) - read a wide character from a FILE stream - [fgetwc\_unlocked](https://manual.cs50.io/3/fgetwc_unlocked) - nonlocking stdio functions - [fgetws\_unlocked](https://manual.cs50.io/3/fgetws_unlocked) - nonlocking stdio functions - [fileno](https://manual.cs50.io/3/fileno) - obtain file descriptor of a stdio stream - [fileno\_unlocked](https://manual.cs50.io/3/fileno_unlocked) - nonlocking stdio functions - [flockfile](https://manual.cs50.io/3/flockfile) - lock FILE for stdio - [fmemopen](https://manual.cs50.io/3/fmemopen) - open memory as stream - [fopen](https://manual.cs50.io/3/fopen) - stream open functions open a file - [fopencookie](https://manual.cs50.io/3/fopencookie) - open a custom stream - [fprintf](https://manual.cs50.io/3/fprintf) - formatted output conversion print to a file - [fpurge](https://manual.cs50.io/3/fpurge) - purge a stream - [fputc](https://manual.cs50.io/3/fputc) - output of characters and strings - [fputc\_unlocked](https://manual.cs50.io/3/fputc_unlocked) - nonlocking stdio functions - [fputs](https://manual.cs50.io/3/fputs) - output of characters and strings - [fputs\_unlocked](https://manual.cs50.io/3/fputs_unlocked) - nonlocking stdio functions - [fputwc](https://manual.cs50.io/3/fputwc) - write a wide character to a FILE stream - [fputwc\_unlocked](https://manual.cs50.io/3/fputwc_unlocked) - nonlocking stdio functions - [fputws\_unlocked](https://manual.cs50.io/3/fputws_unlocked) - nonlocking stdio functions - [fread](https://manual.cs50.io/3/fread) - binary stream input/output read bytes from a file - [fread\_unlocked](https://manual.cs50.io/3/fread_unlocked) - nonlocking stdio functions - [freopen](https://manual.cs50.io/3/freopen) - stream open functions - [fscanf](https://manual.cs50.io/3/fscanf) - input FILE format conversion get input from a file - [fseek](https://manual.cs50.io/3/fseek) - reposition a stream - [fseeko](https://manual.cs50.io/3/fseeko) - seek to or report file position - [fsetpos](https://manual.cs50.io/3/fsetpos) - reposition a stream - [ftell](https://manual.cs50.io/3/ftell) - reposition a stream - [ftello](https://manual.cs50.io/3/ftello) - seek to or report file position - [ftrylockfile](https://manual.cs50.io/3/ftrylockfile) - lock FILE for stdio - [funlockfile](https://manual.cs50.io/3/funlockfile) - lock FILE for stdio - [fwprintf](https://manual.cs50.io/3/fwprintf) - formatted wide-character output conversion - [fwrite](https://manual.cs50.io/3/fwrite) - binary stream input/output write bytes to a file - [fwrite\_unlocked](https://manual.cs50.io/3/fwrite_unlocked) - nonlocking stdio functions - [getc](https://manual.cs50.io/3/getc) - input of characters and strings - [getc\_unlocked](https://manual.cs50.io/3/getc_unlocked) - nonlocking stdio functions - [getchar](https://manual.cs50.io/3/getchar) - input of characters and strings - [getchar\_unlocked](https://manual.cs50.io/3/getchar_unlocked) - nonlocking stdio functions - [getdelim](https://manual.cs50.io/3/getdelim) - delimited string input - [getline](https://manual.cs50.io/3/getline) - delimited string input - [getmntent](https://manual.cs50.io/3/getmntent) - get filesystem descriptor file entry - [getmntent\_r](https://manual.cs50.io/3/getmntent_r) - get filesystem descriptor file entry - [gets](https://manual.cs50.io/3/gets) - get a string from standard input (DEPRECATED) - [getw](https://manual.cs50.io/3/getw) - input and output of words (ints) - [getwc](https://manual.cs50.io/3/getwc) - read a wide character from a FILE stream - [getwc\_unlocked](https://manual.cs50.io/3/getwc_unlocked) - nonlocking stdio functions - [getwchar\_unlocked](https://manual.cs50.io/3/getwchar_unlocked) - nonlocking stdio functions - [hasmntopt](https://manual.cs50.io/3/hasmntopt) - get filesystem descriptor file entry - [open\_memstream](https://manual.cs50.io/3/open_memstream) - open a dynamic memory buffer stream - [open\_wmemstream](https://manual.cs50.io/3/open_wmemstream) - open a dynamic memory buffer stream - [pclose](https://manual.cs50.io/3/pclose) - pipe stream to or from a process - [perror](https://manual.cs50.io/3/perror) - print a system error message - [popen](https://manual.cs50.io/3/popen) - pipe stream to or from a process - [printf](https://manual.cs50.io/3/printf) - formatted output conversion print to the screen - [putc](https://manual.cs50.io/3/putc) - output of characters and strings - [putc\_unlocked](https://manual.cs50.io/3/putc_unlocked) - nonlocking stdio functions - [putchar](https://manual.cs50.io/3/putchar) - output of characters and strings - [putchar\_unlocked](https://manual.cs50.io/3/putchar_unlocked) - nonlocking stdio functions - [putpwent](https://manual.cs50.io/3/putpwent) - write a password file entry - [puts](https://manual.cs50.io/3/puts) - output of characters and strings - [putw](https://manual.cs50.io/3/putw) - input and output of words (ints) - [putwc](https://manual.cs50.io/3/putwc) - write a wide character to a FILE stream - [putwc\_unlocked](https://manual.cs50.io/3/putwc_unlocked) - nonlocking stdio functions - [putwchar\_unlocked](https://manual.cs50.io/3/putwchar_unlocked) - nonlocking stdio functions - [remove](https://manual.cs50.io/3/remove) - remove a file or directory - [rename](https://manual.cs50.io/2/rename) - change the name or location of a file - [renameat](https://manual.cs50.io/2/renameat) - change the name or location of a file - [renameat2](https://manual.cs50.io/2/renameat2) - change the name or location of a file - [rewind](https://manual.cs50.io/3/rewind) - reposition a stream - [scanf](https://manual.cs50.io/3/scanf) - input FILE format conversion get input from a user - [setbuf](https://manual.cs50.io/3/setbuf) - stream buffering operations - [setbuffer](https://manual.cs50.io/3/setbuffer) - stream buffering operations - [setlinebuf](https://manual.cs50.io/3/setlinebuf) - stream buffering operations - [setmntent](https://manual.cs50.io/3/setmntent) - get filesystem descriptor file entry - [setvbuf](https://manual.cs50.io/3/setvbuf) - stream buffering operations - [snprintf](https://manual.cs50.io/3/snprintf) - formatted output conversion - [sprintf](https://manual.cs50.io/3/sprintf) - formatted output conversion print to a string - [sscanf](https://manual.cs50.io/3/sscanf) - input string format conversion - [stderr](https://manual.cs50.io/3/stderr) - standard I/O streams - [stdin](https://manual.cs50.io/3/stdin) - standard I/O streams - [stdio](https://manual.cs50.io/3/stdio) - standard input/output library functions - [stdio\_ext](https://manual.cs50.io/3/stdio_ext) - interfaces to stdio FILE structure - [stdout](https://manual.cs50.io/3/stdout) - standard I/O streams - [swprintf](https://manual.cs50.io/3/swprintf) - formatted wide-character output conversion - [sys\_errlist](https://manual.cs50.io/3/sys_errlist) - print a system error message - [sys\_nerr](https://manual.cs50.io/3/sys_nerr) - print a system error message - [tempnam](https://manual.cs50.io/3/tempnam) - create a name for a temporary file - [tmpfile](https://manual.cs50.io/3/tmpfile) - create a temporary file - [tmpnam](https://manual.cs50.io/3/tmpnam) - create a name for a temporary file - [tmpnam\_r](https://manual.cs50.io/3/tmpnam_r) - create a name for a temporary file - [ungetc](https://manual.cs50.io/3/ungetc) - input of characters and strings - [unlocked\_stdio](https://manual.cs50.io/3/unlocked_stdio) - nonlocking stdio functions - [vasprintf](https://manual.cs50.io/3/vasprintf) - print to allocated string - [vdprintf](https://manual.cs50.io/3/vdprintf) - formatted output conversion - [vfprintf](https://manual.cs50.io/3/vfprintf) - formatted output conversion - [vfscanf](https://manual.cs50.io/3/vfscanf) - input FILE format conversion - [vfwprintf](https://manual.cs50.io/3/vfwprintf) - formatted wide-character output conversion - [vprintf](https://manual.cs50.io/3/vprintf) - formatted output conversion - [vscanf](https://manual.cs50.io/3/vscanf) - input FILE format conversion - [vsnprintf](https://manual.cs50.io/3/vsnprintf) - formatted output conversion - [vsprintf](https://manual.cs50.io/3/vsprintf) - formatted output conversion - [vsscanf](https://manual.cs50.io/3/vsscanf) - input string format conversion - [vswprintf](https://manual.cs50.io/3/vswprintf) - formatted wide-character output conversion - [vwprintf](https://manual.cs50.io/3/vwprintf) - formatted wide-character output conversion - [wprintf](https://manual.cs50.io/3/wprintf) - formatted wide-character output conversion ## [stdlib.h](https://manual.cs50.io/#stdlib.h) - [a64l](https://manual.cs50.io/3/a64l) - convert between long and base-64 - [abort](https://manual.cs50.io/3/abort) - cause abnormal process termination - [abs](https://manual.cs50.io/3/abs) - compute the absolute value of an integer - [aligned\_alloc](https://manual.cs50.io/3/aligned_alloc) - allocate aligned memory - [arc4random](https://manual.cs50.io/3/arc4random) - cryptographically-secure pseudorandom number generator - [arc4random\_buf](https://manual.cs50.io/3/arc4random_buf) - cryptographically-secure pseudorandom number generator - [arc4random\_uniform](https://manual.cs50.io/3/arc4random_uniform) - cryptographically-secure pseudorandom number generator - [atexit](https://manual.cs50.io/3/atexit) - register a function to be called at normal process ter... - [atof](https://manual.cs50.io/3/atof) - convert a string to a double convert a `string` to a `float` - [atoi](https://manual.cs50.io/3/atoi) - convert a string to an integer convert a `string` to an `int` - [atol](https://manual.cs50.io/3/atol) - convert a string to an integer convert a `string` to a `long` - [atoll](https://manual.cs50.io/3/atoll) - convert a string to an integer - [atoq](https://manual.cs50.io/3/atoq) - convert a string to an integer - [bsearch](https://manual.cs50.io/3/bsearch) - binary search of a sorted array - [calloc](https://manual.cs50.io/3/calloc) - allocate and free dynamic memory - [canonicalize\_file\_name](https://manual.cs50.io/3/canonicalize_file_name) - return the canonicalized absolute pathname - [cfree](https://manual.cs50.io/3/cfree) - free allocated memory - [clearenv](https://manual.cs50.io/3/clearenv) - clear the environment - [div](https://manual.cs50.io/3/div) - compute quotient and remainder of an integer division - [drand48](https://manual.cs50.io/3/drand48) - generate uniformly distributed pseudo-random numbers - [drand48\_r](https://manual.cs50.io/3/drand48_r) - generate uniformly distributed pseudo-random numbers r... - [ecvt](https://manual.cs50.io/3/ecvt) - convert a floating-point number to a string - [ecvt\_r](https://manual.cs50.io/3/ecvt_r) - convert a floating-point number to a string - [erand48](https://manual.cs50.io/3/erand48) - generate uniformly distributed pseudo-random numbers - [erand48\_r](https://manual.cs50.io/3/erand48_r) - generate uniformly distributed pseudo-random numbers r... - [exit](https://manual.cs50.io/3/exit) - cause normal process termination - [fcvt](https://manual.cs50.io/3/fcvt) - convert a floating-point number to a string - [fcvt\_r](https://manual.cs50.io/3/fcvt_r) - convert a floating-point number to a string - [free](https://manual.cs50.io/3/free) - allocate and free dynamic memory free dynamically allocated memory - [gcvt](https://manual.cs50.io/3/gcvt) - convert a floating-point number to a string - [getenv](https://manual.cs50.io/3/getenv) - get an environment variable - [getloadavg](https://manual.cs50.io/3/getloadavg) - get system load averages - [getpt](https://manual.cs50.io/3/getpt) - open a new pseudoterminal master - [getsubopt](https://manual.cs50.io/3/getsubopt) - parse suboption arguments from a string - [grantpt](https://manual.cs50.io/3/grantpt) - grant access to the slave pseudoterminal - [imaxabs](https://manual.cs50.io/3/imaxabs) - compute the absolute value of an integer - [imaxdiv](https://manual.cs50.io/3/imaxdiv) - compute quotient and remainder of an integer division - [initstate](https://manual.cs50.io/3/initstate) - random number generator - [initstate\_r](https://manual.cs50.io/3/initstate_r) - reentrant random number generator - [jrand48](https://manual.cs50.io/3/jrand48) - generate uniformly distributed pseudo-random numbers - [jrand48\_r](https://manual.cs50.io/3/jrand48_r) - generate uniformly distributed pseudo-random numbers r... - [l64a](https://manual.cs50.io/3/l64a) - convert between long and base-64 - [labs](https://manual.cs50.io/3/labs) - compute the absolute value of an integer - [lcong48](https://manual.cs50.io/3/lcong48) - generate uniformly distributed pseudo-random numbers - [lcong48\_r](https://manual.cs50.io/3/lcong48_r) - generate uniformly distributed pseudo-random numbers r... - [ldiv](https://manual.cs50.io/3/ldiv) - compute quotient and remainder of an integer division - [llabs](https://manual.cs50.io/3/llabs) - compute the absolute value of an integer - [lldiv](https://manual.cs50.io/3/lldiv) - compute quotient and remainder of an integer division - [lrand48](https://manual.cs50.io/3/lrand48) - generate uniformly distributed pseudo-random numbers - [lrand48\_r](https://manual.cs50.io/3/lrand48_r) - generate uniformly distributed pseudo-random numbers r... - [malloc](https://manual.cs50.io/3/malloc) - allocate and free dynamic memory allocate memory dynamically - [MB\_CUR\_MAX](https://manual.cs50.io/3/MB_CUR_MAX) - maximum length of a multibyte character in the current... - [mblen](https://manual.cs50.io/3/mblen) - determine number of bytes in next multibyte character - [mbstowcs](https://manual.cs50.io/3/mbstowcs) - convert a multibyte string to a wide-character string - [mbtowc](https://manual.cs50.io/3/mbtowc) - convert a multibyte sequence to a wide character - [memalign](https://manual.cs50.io/3/memalign) - allocate aligned memory - [mkdtemp](https://manual.cs50.io/3/mkdtemp) - create a unique temporary directory - [mkostemp](https://manual.cs50.io/3/mkostemp) - create a unique temporary file - [mkostemps](https://manual.cs50.io/3/mkostemps) - create a unique temporary file - [mkstemp](https://manual.cs50.io/3/mkstemp) - create a unique temporary file - [mkstemps](https://manual.cs50.io/3/mkstemps) - create a unique temporary file - [mktemp](https://manual.cs50.io/3/mktemp) - make a unique temporary filename - [mrand48](https://manual.cs50.io/3/mrand48) - generate uniformly distributed pseudo-random numbers - [mrand48\_r](https://manual.cs50.io/3/mrand48_r) - generate uniformly distributed pseudo-random numbers r... - [nrand48](https://manual.cs50.io/3/nrand48) - generate uniformly distributed pseudo-random numbers - [nrand48\_r](https://manual.cs50.io/3/nrand48_r) - generate uniformly distributed pseudo-random numbers r... - [on\_exit](https://manual.cs50.io/3/on_exit) - register a function to be called at normal process ter... - [posix\_memalign](https://manual.cs50.io/3/posix_memalign) - allocate aligned memory - [posix\_openpt](https://manual.cs50.io/3/posix_openpt) - open a pseudoterminal device - [ptsname](https://manual.cs50.io/3/ptsname) - get the name of the slave pseudoterminal - [ptsname\_r](https://manual.cs50.io/3/ptsname_r) - get the name of the slave pseudoterminal - [putenv](https://manual.cs50.io/3/putenv) - change or add an environment variable - [pvalloc](https://manual.cs50.io/3/pvalloc) - allocate aligned memory - [qecvt](https://manual.cs50.io/3/qecvt) - convert a floating-point number to a string - [qecvt\_r](https://manual.cs50.io/3/qecvt_r) - convert a floating-point number to a string - [qfcvt](https://manual.cs50.io/3/qfcvt) - convert a floating-point number to a string - [qfcvt\_r](https://manual.cs50.io/3/qfcvt_r) - convert a floating-point number to a string - [qgcvt](https://manual.cs50.io/3/qgcvt) - convert a floating-point number to a string - [qsort](https://manual.cs50.io/3/qsort) - sort an array - [qsort\_r](https://manual.cs50.io/3/qsort_r) - sort an array - [rand](https://manual.cs50.io/3/rand) - pseudo-random number generator - [rand\_r](https://manual.cs50.io/3/rand_r) - pseudo-random number generator - [random](https://manual.cs50.io/3/random) - random number generator generate a pseudorandom number - [random\_r](https://manual.cs50.io/3/random_r) - reentrant random number generator - [realloc](https://manual.cs50.io/3/realloc) - allocate and free dynamic memory reallocate memory dynamically - [reallocarray](https://manual.cs50.io/3/reallocarray) - allocate and free dynamic memory - [rpmatch](https://manual.cs50.io/3/rpmatch) - determine if the answer to a question is affirmative o... - [secure\_getenv](https://manual.cs50.io/3/secure_getenv) - get an environment variable - [seed48](https://manual.cs50.io/3/seed48) - generate uniformly distributed pseudo-random numbers - [seed48\_r](https://manual.cs50.io/3/seed48_r) - generate uniformly distributed pseudo-random numbers r... - [setenv](https://manual.cs50.io/3/setenv) - change or add an environment variable - [setstate](https://manual.cs50.io/3/setstate) - random number generator - [setstate\_r](https://manual.cs50.io/3/setstate_r) - reentrant random number generator - [srand](https://manual.cs50.io/3/srand) - pseudo-random number generator - [srand48](https://manual.cs50.io/3/srand48) - generate uniformly distributed pseudo-random numbers - [srand48\_r](https://manual.cs50.io/3/srand48_r) - generate uniformly distributed pseudo-random numbers r... - [srandom](https://manual.cs50.io/3/srandom) - random number generator seed pseudorandom number generation - [srandom\_r](https://manual.cs50.io/3/srandom_r) - reentrant random number generator - [strfromd](https://manual.cs50.io/3/strfromd) - convert a floating-point value into a string - [strfromf](https://manual.cs50.io/3/strfromf) - convert a floating-point value into a string - [strfroml](https://manual.cs50.io/3/strfroml) - convert a floating-point value into a string - [strtod](https://manual.cs50.io/3/strtod) - convert ASCII string to floating-point number - [strtof](https://manual.cs50.io/3/strtof) - convert ASCII string to floating-point number - [strtol](https://manual.cs50.io/3/strtol) - convert a string to a long integer - [strtold](https://manual.cs50.io/3/strtold) - convert ASCII string to floating-point number - [strtoll](https://manual.cs50.io/3/strtoll) - convert a string to a long integer - [strtoq](https://manual.cs50.io/3/strtoq) - convert a string to a long integer - [strtoul](https://manual.cs50.io/3/strtoul) - convert a string to an unsigned long integer - [strtoull](https://manual.cs50.io/3/strtoull) - convert a string to an unsigned long integer - [strtouq](https://manual.cs50.io/3/strtouq) - convert a string to an unsigned long integer - [system](https://manual.cs50.io/3/system) - execute a shell command - [unlockpt](https://manual.cs50.io/3/unlockpt) - unlock a pseudoterminal master/slave pair - [unsetenv](https://manual.cs50.io/3/unsetenv) - change or add an environment variable - [valloc](https://manual.cs50.io/3/valloc) - allocate aligned memory - [wcstombs](https://manual.cs50.io/3/wcstombs) - convert a wide-character string to a multibyte string - [wctomb](https://manual.cs50.io/3/wctomb) - convert a wide character to a multibyte sequence ## [string.h](https://manual.cs50.io/#string.h) - [bstring](https://manual.cs50.io/3/bstring) - byte string operations - [memccpy](https://manual.cs50.io/3/memccpy) - copy memory area - [memchr](https://manual.cs50.io/3/memchr) - scan memory for a character - [memcmp](https://manual.cs50.io/3/memcmp) - compare memory areas - [memcpy](https://manual.cs50.io/3/memcpy) - copy memory area - [memfrob](https://manual.cs50.io/3/memfrob) - frobnicate (obfuscate) a memory area - [memmem](https://manual.cs50.io/3/memmem) - locate a substring - [memmove](https://manual.cs50.io/3/memmove) - copy memory area - [mempcpy](https://manual.cs50.io/3/mempcpy) - copy memory area - [memrchr](https://manual.cs50.io/3/memrchr) - scan memory for a character - [memset](https://manual.cs50.io/3/memset) - fill memory with a constant byte - [rawmemchr](https://manual.cs50.io/3/rawmemchr) - scan memory for a character - [sigabbrev\_np](https://manual.cs50.io/3/sigabbrev_np) - return string describing signal - [sigdescr\_np](https://manual.cs50.io/3/sigdescr_np) - return string describing signal - [stpcpy](https://manual.cs50.io/3/stpcpy) - copy or catenate a string - [stpncpy](https://manual.cs50.io/3/stpncpy) - fill a fixed-size buffer with non-null bytes from a st... - [strcasestr](https://manual.cs50.io/3/strcasestr) - locate a substring locate a substring - [strcat](https://manual.cs50.io/3/strcat) - copy or catenate a string - [strchr](https://manual.cs50.io/3/strchr) - locate character in string - [strchrnul](https://manual.cs50.io/3/strchrnul) - locate character in string - [strcmp](https://manual.cs50.io/3/strcmp) - compare two strings compare two strings - [strcoll](https://manual.cs50.io/3/strcoll) - compare two strings using the current locale - [strcpy](https://manual.cs50.io/3/strcpy) - copy or catenate a string copy a string - [strcspn](https://manual.cs50.io/3/strcspn) - get length of a prefix substring - [strdup](https://manual.cs50.io/3/strdup) - duplicate a string - [strdupa](https://manual.cs50.io/3/strdupa) - duplicate a string - [strerror](https://manual.cs50.io/3/strerror) - return string describing error number - [strerror\_l](https://manual.cs50.io/3/strerror_l) - return string describing error number - [strerror\_r](https://manual.cs50.io/3/strerror_r) - return string describing error number - [strerrordesc\_np](https://manual.cs50.io/3/strerrordesc_np) - return string describing error number - [strerrorname\_np](https://manual.cs50.io/3/strerrorname_np) - return string describing error number - [strfry](https://manual.cs50.io/3/strfry) - randomize a string - [strlen](https://manual.cs50.io/3/strlen) - calculate the length of a string calculate the length of a string - [strncat](https://manual.cs50.io/3/strncat) - append non-null bytes from a source array to a string,... - [strncmp](https://manual.cs50.io/3/strncmp) - compare two strings - [strncpy](https://manual.cs50.io/3/strncpy) - fill a fixed-size buffer with non-null bytes from a st... - [strndup](https://manual.cs50.io/3/strndup) - duplicate a string - [strndupa](https://manual.cs50.io/3/strndupa) - duplicate a string - [strnlen](https://manual.cs50.io/3/strnlen) - determine the length of a fixed-size string - [strpbrk](https://manual.cs50.io/3/strpbrk) - search a string for any of a set of bytes - [strrchr](https://manual.cs50.io/3/strrchr) - locate character in string - [strsep](https://manual.cs50.io/3/strsep) - extract token from string - [strsignal](https://manual.cs50.io/3/strsignal) - return string describing signal - [strspn](https://manual.cs50.io/3/strspn) - get length of a prefix substring - [strstr](https://manual.cs50.io/3/strstr) - locate a substring locate a substring - [strtok](https://manual.cs50.io/3/strtok) - extract tokens from strings - [strtok\_r](https://manual.cs50.io/3/strtok_r) - extract tokens from strings - [strverscmp](https://manual.cs50.io/3/strverscmp) - compare two version strings - [strxfrm](https://manual.cs50.io/3/strxfrm) - string transformation - [sys\_siglist](https://manual.cs50.io/3/sys_siglist) - return string describing signal - [wmempcpy](https://manual.cs50.io/3/wmempcpy) - copy memory area ## [strings.h](https://manual.cs50.io/#strings.h) - [bcmp](https://manual.cs50.io/3/bcmp) - compare byte sequences - [bcopy](https://manual.cs50.io/3/bcopy) - copy byte sequence - [bzero](https://manual.cs50.io/3/bzero) - zero a byte string - [explicit\_bzero](https://manual.cs50.io/3/explicit_bzero) - zero a byte string - [ffs](https://manual.cs50.io/3/ffs) - find first bit set in a word - [ffsl](https://manual.cs50.io/3/ffsl) - find first bit set in a word - [ffsll](https://manual.cs50.io/3/ffsll) - find first bit set in a word - [index](https://manual.cs50.io/3/index) - locate character in string - [rindex](https://manual.cs50.io/3/rindex) - locate character in string - [strcasecmp](https://manual.cs50.io/3/strcasecmp) - compare two strings ignoring case compare two strings ignoring case - [string](https://manual.cs50.io/3/string) - string operations - [strncasecmp](https://manual.cs50.io/3/strncasecmp) - compare two strings ignoring case ## [sys/ipc.h](https://manual.cs50.io/#sys/ipc.h) - [ftok](https://manual.cs50.io/3/ftok) - convert a pathname and a project identifier to a Syste... ## [sys/mman.h](https://manual.cs50.io/#sys/mman.h) - [madvise](https://manual.cs50.io/2/madvise) - give advice about use of memory - [memfd\_create](https://manual.cs50.io/2/memfd_create) - create an anonymous file - [mincore](https://manual.cs50.io/2/mincore) - determine whether pages are resident in memory - [mlock](https://manual.cs50.io/2/mlock) - lock and unlock memory - [mlock2](https://manual.cs50.io/2/mlock2) - lock and unlock memory - [mlockall](https://manual.cs50.io/2/mlockall) - lock and unlock memory - [mmap](https://manual.cs50.io/2/mmap) - map or unmap files or devices into memory - [mmap64](https://manual.cs50.io/3/mmap64) - map or unmap files or devices into memory - [mprotect](https://manual.cs50.io/2/mprotect) - set protection on a region of memory - [mremap](https://manual.cs50.io/2/mremap) - remap a virtual memory address - [msync](https://manual.cs50.io/2/msync) - synchronize a file with a memory map - [munlock](https://manual.cs50.io/2/munlock) - lock and unlock memory - [munlockall](https://manual.cs50.io/2/munlockall) - lock and unlock memory - [munmap](https://manual.cs50.io/2/munmap) - map or unmap files or devices into memory - [pkey\_alloc](https://manual.cs50.io/2/pkey_alloc) - allocate or free a protection key - [pkey\_free](https://manual.cs50.io/2/pkey_free) - allocate or free a protection key - [pkey\_mprotect](https://manual.cs50.io/2/pkey_mprotect) - set protection on a region of memory - [posix\_madvise](https://manual.cs50.io/3/posix_madvise) - give advice about patterns of memory usage - [process\_madvise](https://manual.cs50.io/2/process_madvise) - give advice about use of memory to a process - [remap\_file\_pages](https://manual.cs50.io/2/remap_file_pages) - create a nonlinear file mapping - [shm\_open](https://manual.cs50.io/3/shm_open) - create/open or unlink POSIX shared memory objects - [shm\_unlink](https://manual.cs50.io/3/shm_unlink) - create/open or unlink POSIX shared memory objects ## [sys/msg.h](https://manual.cs50.io/#sys/msg.h) - [msgctl](https://manual.cs50.io/2/msgctl) - System V message control operations - [msgget](https://manual.cs50.io/2/msgget) - get a System V message queue identifier - [msgop](https://manual.cs50.io/2/msgop) - System V message queue operations - [msgrcv](https://manual.cs50.io/2/msgrcv) - System V message queue operations - [msgsnd](https://manual.cs50.io/2/msgsnd) - System V message queue operations ## [sys/resource.h](https://manual.cs50.io/#sys/resource.h) - [getpriority](https://manual.cs50.io/2/getpriority) - get/set program scheduling priority - [getrlimit](https://manual.cs50.io/2/getrlimit) - get/set resource limits - [getrusage](https://manual.cs50.io/2/getrusage) - get resource usage - [prlimit](https://manual.cs50.io/2/prlimit) - get/set resource limits - [prlimit64](https://manual.cs50.io/2/prlimit64) - get/set resource limits - [setpriority](https://manual.cs50.io/2/setpriority) - get/set program scheduling priority - [setrlimit](https://manual.cs50.io/2/setrlimit) - get/set resource limits - [ugetrlimit](https://manual.cs50.io/2/ugetrlimit) - get/set resource limits - [vlimit](https://manual.cs50.io/3/vlimit) - get/set resource limits - [vtimes](https://manual.cs50.io/3/vtimes) - get resource usage ## [sys/select.h](https://manual.cs50.io/#sys/select.h) - [\_newselect](https://manual.cs50.io/2/_newselect) - synchronous I/O multiplexing - [FD\_CLR](https://manual.cs50.io/3/FD_CLR) - synchronous I/O multiplexing - [FD\_ISSET](https://manual.cs50.io/3/FD_ISSET) - synchronous I/O multiplexing - [FD\_SET](https://manual.cs50.io/3/FD_SET) - synchronous I/O multiplexing - [FD\_ZERO](https://manual.cs50.io/3/FD_ZERO) - synchronous I/O multiplexing - [pselect](https://manual.cs50.io/2/pselect) - synchronous I/O multiplexing - [pselect6](https://manual.cs50.io/2/pselect6) - synchronous I/O multiplexing - [select](https://manual.cs50.io/2/select) - synchronous I/O multiplexing ## [sys/sem.h](https://manual.cs50.io/#sys/sem.h) - [semctl](https://manual.cs50.io/2/semctl) - System V semaphore control operations - [semget](https://manual.cs50.io/2/semget) - get a System V semaphore set identifier - [semop](https://manual.cs50.io/2/semop) - System V semaphore operations - [semtimedop](https://manual.cs50.io/2/semtimedop) - System V semaphore operations ## [sys/shm.h](https://manual.cs50.io/#sys/shm.h) - [shmat](https://manual.cs50.io/2/shmat) - System V shared memory operations - [shmctl](https://manual.cs50.io/2/shmctl) - System V shared memory control - [shmdt](https://manual.cs50.io/2/shmdt) - System V shared memory operations - [shmget](https://manual.cs50.io/2/shmget) - allocates a System V shared memory segment - [shmop](https://manual.cs50.io/2/shmop) - System V shared memory operations ## [sys/socket.h](https://manual.cs50.io/#sys/socket.h) - [accept](https://manual.cs50.io/2/accept) - accept a connection on a socket - [accept4](https://manual.cs50.io/2/accept4) - accept a connection on a socket - [address\_families](https://manual.cs50.io/7/address_families) - socket address families (domains) - [bind](https://manual.cs50.io/2/bind) - bind a name to a socket - [cmsg](https://manual.cs50.io/3/cmsg) - access ancillary data - [CMSG\_ALIGN](https://manual.cs50.io/3/CMSG_ALIGN) - access ancillary data - [CMSG\_DATA](https://manual.cs50.io/3/CMSG_DATA) - access ancillary data - [CMSG\_FIRSTHDR](https://manual.cs50.io/3/CMSG_FIRSTHDR) - access ancillary data - [CMSG\_LEN](https://manual.cs50.io/3/CMSG_LEN) - access ancillary data - [CMSG\_NXTHDR](https://manual.cs50.io/3/CMSG_NXTHDR) - access ancillary data - [CMSG\_SPACE](https://manual.cs50.io/3/CMSG_SPACE) - access ancillary data - [connect](https://manual.cs50.io/2/connect) - initiate a connection on a socket - [ddp](https://manual.cs50.io/7/ddp) - Linux AppleTalk protocol implementation - [getnameinfo](https://manual.cs50.io/3/getnameinfo) - address-to-name translation in protocol-independent ma... - [getpeername](https://manual.cs50.io/2/getpeername) - get name of connected peer socket - [getsockname](https://manual.cs50.io/2/getsockname) - get socket name - [getsockopt](https://manual.cs50.io/2/getsockopt) - get and set options on sockets - [inet](https://manual.cs50.io/3/inet) - Internet address manipulation routines - [inet\_addr](https://manual.cs50.io/3/inet_addr) - Internet address manipulation routines - [inet\_aton](https://manual.cs50.io/3/inet_aton) - Internet address manipulation routines - [inet\_lnaof](https://manual.cs50.io/3/inet_lnaof) - Internet address manipulation routines - [inet\_makeaddr](https://manual.cs50.io/3/inet_makeaddr) - Internet address manipulation routines - [inet\_netof](https://manual.cs50.io/3/inet_netof) - Internet address manipulation routines - [inet\_network](https://manual.cs50.io/3/inet_network) - Internet address manipulation routines - [inet\_ntoa](https://manual.cs50.io/3/inet_ntoa) - Internet address manipulation routines - [ip](https://manual.cs50.io/7/ip) - Linux IPv4 protocol implementation - [ipv6](https://manual.cs50.io/7/ipv6) - Linux IPv6 protocol implementation - [listen](https://manual.cs50.io/2/listen) - listen for connections on a socket - [packet](https://manual.cs50.io/7/packet) - packet interface on device level - [raw](https://manual.cs50.io/7/raw) - Linux IPv4 raw sockets - [recv](https://manual.cs50.io/2/recv) - receive a message from a socket - [recvfrom](https://manual.cs50.io/2/recvfrom) - receive a message from a socket - [recvmmsg](https://manual.cs50.io/2/recvmmsg) - receive multiple messages on a socket - [recvmsg](https://manual.cs50.io/2/recvmsg) - receive a message from a socket - [send](https://manual.cs50.io/2/send) - send a message on a socket - [sendmmsg](https://manual.cs50.io/2/sendmmsg) - send multiple messages on a socket - [sendmsg](https://manual.cs50.io/2/sendmsg) - send a message on a socket - [sendto](https://manual.cs50.io/2/sendto) - send a message on a socket - [setsockopt](https://manual.cs50.io/2/setsockopt) - get and set options on sockets - [shutdown](https://manual.cs50.io/2/shutdown) - shut down part of a full-duplex connection - [sock\_diag](https://manual.cs50.io/7/sock_diag) - obtaining information about sockets - [sockatmark](https://manual.cs50.io/3/sockatmark) - determine whether socket is at out-of-band mark - [socket](https://manual.cs50.io/2/socket) - create an endpoint for communication - [socket](https://manual.cs50.io/7/socket) - Linux socket interface - [socketpair](https://manual.cs50.io/2/socketpair) - create a pair of connected sockets - [tcp](https://manual.cs50.io/7/tcp) - TCP protocol - [udp](https://manual.cs50.io/7/udp) - User Datagram Protocol for IPv4 - [udplite](https://manual.cs50.io/7/udplite) - Lightweight User Datagram Protocol - [unix](https://manual.cs50.io/7/unix) - sockets for local interprocess communication - [vsock](https://manual.cs50.io/7/vsock) - Linux VSOCK address family - [x25](https://manual.cs50.io/7/x25) - ITU-T X.25 / ISO/IEC 8208 protocol interface ## [sys/stat.h](https://manual.cs50.io/#sys/stat.h) - [chmod](https://manual.cs50.io/2/chmod) - change permissions of a file - [fchmod](https://manual.cs50.io/2/fchmod) - change permissions of a file - [fchmodat](https://manual.cs50.io/2/fchmodat) - change permissions of a file - [fstat](https://manual.cs50.io/2/fstat) - get file status - [fstat64](https://manual.cs50.io/2/fstat64) - get file status - [fstatat](https://manual.cs50.io/2/fstatat) - get file status - [fstatat64](https://manual.cs50.io/2/fstatat64) - get file status - [futimens](https://manual.cs50.io/3/futimens) - change file timestamps with nanosecond precision - [isfdtype](https://manual.cs50.io/3/isfdtype) - test file type of a file descriptor - [lstat](https://manual.cs50.io/2/lstat) - get file status - [lstat64](https://manual.cs50.io/2/lstat64) - get file status - [mkdir](https://manual.cs50.io/2/mkdir) - create a directory - [mkdirat](https://manual.cs50.io/2/mkdirat) - create a directory - [mknod](https://manual.cs50.io/2/mknod) - create a special or ordinary file - [mknodat](https://manual.cs50.io/2/mknodat) - create a special or ordinary file - [newfstatat](https://manual.cs50.io/2/newfstatat) - get file status - [oldfstat](https://manual.cs50.io/2/oldfstat) - get file status - [oldlstat](https://manual.cs50.io/2/oldlstat) - get file status - [oldstat](https://manual.cs50.io/2/oldstat) - get file status - [stat](https://manual.cs50.io/2/stat) - get file status - [stat64](https://manual.cs50.io/2/stat64) - get file status - [statx](https://manual.cs50.io/2/statx) - get file status (extended) - [umask](https://manual.cs50.io/2/umask) - set file mode creation mask - [utimensat](https://manual.cs50.io/2/utimensat) - change file timestamps with nanosecond precision ## [sys/statvfs.h](https://manual.cs50.io/#sys/statvfs.h) - [fstatvfs](https://manual.cs50.io/3/fstatvfs) - get filesystem statistics - [statvfs](https://manual.cs50.io/3/statvfs) - get filesystem statistics ## [sys/time.h](https://manual.cs50.io/#sys/time.h) - [adjtime](https://manual.cs50.io/3/adjtime) - correct the time to synchronize the system clock - [futimes](https://manual.cs50.io/3/futimes) - change file timestamps - [futimesat](https://manual.cs50.io/2/futimesat) - change timestamps of a file relative to a directory fi... - [getitimer](https://manual.cs50.io/2/getitimer) - get or set value of an interval timer - [gettimeofday](https://manual.cs50.io/2/gettimeofday) - get / set time - [lutimes](https://manual.cs50.io/3/lutimes) - change file timestamps - [setitimer](https://manual.cs50.io/2/setitimer) - get or set value of an interval timer - [settimeofday](https://manual.cs50.io/2/settimeofday) - get / set time - [timeradd](https://manual.cs50.io/3/timeradd) - timeval operations - [timerclear](https://manual.cs50.io/3/timerclear) - timeval operations - [timercmp](https://manual.cs50.io/3/timercmp) - timeval operations - [timerisset](https://manual.cs50.io/3/timerisset) - timeval operations - [timersub](https://manual.cs50.io/3/timersub) - timeval operations - [TIMESPEC\_TO\_TIMEVAL](https://manual.cs50.io/3/TIMESPEC_TO_TIMEVAL) - convert between time structures - [TIMEVAL\_TO\_TIMESPEC](https://manual.cs50.io/3/TIMEVAL_TO_TIMESPEC) - convert between time structures ## [sys/times.h](https://manual.cs50.io/#sys/times.h) - [times](https://manual.cs50.io/2/times) - get process times ## [sys/types.h](https://manual.cs50.io/#sys/types.h) - [bindresvport](https://manual.cs50.io/3/bindresvport) - bind a socket to a privileged IP port - [closedir](https://manual.cs50.io/3/closedir) - close a directory - [db](https://manual.cs50.io/3/db) - database access methods - [dbopen](https://manual.cs50.io/3/dbopen) - database access methods - [dirfd](https://manual.cs50.io/3/dirfd) - get directory stream file descriptor - [endgrent](https://manual.cs50.io/3/endgrent) - get group file entry - [endpwent](https://manual.cs50.io/3/endpwent) - get password file entry - [fdopendir](https://manual.cs50.io/3/fdopendir) - open a directory - [freeaddrinfo](https://manual.cs50.io/3/freeaddrinfo) - network address and service translation - [freehostent](https://manual.cs50.io/3/freehostent) - get network hostnames and addresses - [freeifaddrs](https://manual.cs50.io/3/freeifaddrs) - get interface addresses - [fts](https://manual.cs50.io/3/fts) - traverse a file hierarchy - [fts\_children](https://manual.cs50.io/3/fts_children) - traverse a file hierarchy - [fts\_close](https://manual.cs50.io/3/fts_close) - traverse a file hierarchy - [fts\_open](https://manual.cs50.io/3/fts_open) - traverse a file hierarchy - [fts\_read](https://manual.cs50.io/3/fts_read) - traverse a file hierarchy - [fts\_set](https://manual.cs50.io/3/fts_set) - traverse a file hierarchy - [gai\_strerror](https://manual.cs50.io/3/gai_strerror) - network address and service translation - [getaddrinfo](https://manual.cs50.io/3/getaddrinfo) - network address and service translation - [getgrent](https://manual.cs50.io/3/getgrent) - get group file entry - [getgrgid](https://manual.cs50.io/3/getgrgid) - get group file entry - [getgrgid\_r](https://manual.cs50.io/3/getgrgid_r) - get group file entry - [getgrnam](https://manual.cs50.io/3/getgrnam) - get group file entry - [getgrnam\_r](https://manual.cs50.io/3/getgrnam_r) - get group file entry - [getifaddrs](https://manual.cs50.io/3/getifaddrs) - get interface addresses - [getipnodebyaddr](https://manual.cs50.io/3/getipnodebyaddr) - get network hostnames and addresses - [getipnodebyname](https://manual.cs50.io/3/getipnodebyname) - get network hostnames and addresses - [getpw](https://manual.cs50.io/3/getpw) - reconstruct password line entry - [getpwent](https://manual.cs50.io/3/getpwent) - get password file entry - [getpwnam](https://manual.cs50.io/3/getpwnam) - get password file entry - [getpwnam\_r](https://manual.cs50.io/3/getpwnam_r) - get password file entry - [getpwuid](https://manual.cs50.io/3/getpwuid) - get password file entry - [getpwuid\_r](https://manual.cs50.io/3/getpwuid_r) - get password file entry - [initgroups](https://manual.cs50.io/3/initgroups) - initialize the supplementary group access list - [lseek64](https://manual.cs50.io/3/lseek64) - reposition 64-bit read/write file offset - [mkfifo](https://manual.cs50.io/3/mkfifo) - make a FIFO special file (a named pipe) - [mkfifoat](https://manual.cs50.io/3/mkfifoat) - make a FIFO special file (a named pipe) - [opendir](https://manual.cs50.io/3/opendir) - open a directory - [re\_comp](https://manual.cs50.io/3/re_comp) - BSD regex functions - [re\_exec](https://manual.cs50.io/3/re_exec) - BSD regex functions - [rewinddir](https://manual.cs50.io/3/rewinddir) - reset directory stream - [setgrent](https://manual.cs50.io/3/setgrent) - get group file entry - [setpwent](https://manual.cs50.io/3/setpwent) - get password file entry - [ustat](https://manual.cs50.io/2/ustat) - get filesystem statistics ## [sys/uio.h](https://manual.cs50.io/#sys/uio.h) - [preadv](https://manual.cs50.io/2/preadv) - read or write data into multiple buffers - [preadv2](https://manual.cs50.io/2/preadv2) - read or write data into multiple buffers - [process\_vm\_readv](https://manual.cs50.io/2/process_vm_readv) - transfer data between process address spaces - [process\_vm\_writev](https://manual.cs50.io/2/process_vm_writev) - transfer data between process address spaces - [pwritev](https://manual.cs50.io/2/pwritev) - read or write data into multiple buffers - [pwritev2](https://manual.cs50.io/2/pwritev2) - read or write data into multiple buffers - [readv](https://manual.cs50.io/2/readv) - read or write data into multiple buffers - [writev](https://manual.cs50.io/2/writev) - read or write data into multiple buffers ## [sys/utsname.h](https://manual.cs50.io/#sys/utsname.h) - [oldolduname](https://manual.cs50.io/2/oldolduname) - get name and information about current kernel - [olduname](https://manual.cs50.io/2/olduname) - get name and information about current kernel - [uname](https://manual.cs50.io/2/uname) - get name and information about current kernel ## [sys/wait.h](https://manual.cs50.io/#sys/wait.h) - [wait](https://manual.cs50.io/2/wait) - wait for process to change state - [wait3](https://manual.cs50.io/2/wait3) - wait for process to change state, BSD style - [wait4](https://manual.cs50.io/2/wait4) - wait for process to change state, BSD style - [waitid](https://manual.cs50.io/2/waitid) - wait for process to change state - [waitpid](https://manual.cs50.io/2/waitpid) - wait for process to change state ## [syslog.h](https://manual.cs50.io/#syslog.h) - [closelog](https://manual.cs50.io/3/closelog) - send messages to the system logger - [openlog](https://manual.cs50.io/3/openlog) - send messages to the system logger - [setlogmask](https://manual.cs50.io/3/setlogmask) - set log priority mask - [syslog](https://manual.cs50.io/3/syslog) - send messages to the system logger - [vsyslog](https://manual.cs50.io/3/vsyslog) - send messages to the system logger ## [termios.h](https://manual.cs50.io/#termios.h) - [cfgetispeed](https://manual.cs50.io/3/cfgetispeed) - get and set terminal attributes, line control, get and... - [cfgetospeed](https://manual.cs50.io/3/cfgetospeed) - get and set terminal attributes, line control, get and... - [cfmakeraw](https://manual.cs50.io/3/cfmakeraw) - get and set terminal attributes, line control, get and... - [cfsetispeed](https://manual.cs50.io/3/cfsetispeed) - get and set terminal attributes, line control, get and... - [cfsetospeed](https://manual.cs50.io/3/cfsetospeed) - get and set terminal attributes, line control, get and... - [cfsetspeed](https://manual.cs50.io/3/cfsetspeed) - get and set terminal attributes, line control, get and... - [tcdrain](https://manual.cs50.io/3/tcdrain) - get and set terminal attributes, line control, get and... - [tcflow](https://manual.cs50.io/3/tcflow) - get and set terminal attributes, line control, get and... - [tcflush](https://manual.cs50.io/3/tcflush) - get and set terminal attributes, line control, get and... - [tcgetattr](https://manual.cs50.io/3/tcgetattr) - get and set terminal attributes, line control, get and... - [tcgetsid](https://manual.cs50.io/3/tcgetsid) - get session ID - [tcsendbreak](https://manual.cs50.io/3/tcsendbreak) - get and set terminal attributes, line control, get and... - [tcsetattr](https://manual.cs50.io/3/tcsetattr) - get and set terminal attributes, line control, get and... - [termios](https://manual.cs50.io/3/termios) - get and set terminal attributes, line control, get and... ## [time.h](https://manual.cs50.io/#time.h) - [asctime](https://manual.cs50.io/3/asctime) - transform date and time to broken-down time or ASCII - [asctime\_r](https://manual.cs50.io/3/asctime_r) - transform date and time to broken-down time or ASCII - [clock](https://manual.cs50.io/3/clock) - determine processor time - [clock\_getcpuclockid](https://manual.cs50.io/3/clock_getcpuclockid) - obtain ID of a process CPU-time clock - [clock\_getres](https://manual.cs50.io/2/clock_getres) - clock and time functions - [clock\_gettime](https://manual.cs50.io/2/clock_gettime) - clock and time functions - [clock\_nanosleep](https://manual.cs50.io/2/clock_nanosleep) - high-resolution sleep with specifiable clock - [clock\_settime](https://manual.cs50.io/2/clock_settime) - clock and time functions - [ctime](https://manual.cs50.io/3/ctime) - transform date and time to broken-down time or ASCII - [ctime\_r](https://manual.cs50.io/3/ctime_r) - transform date and time to broken-down time or ASCII - [daylight](https://manual.cs50.io/3/daylight) - initialize time conversion information - [difftime](https://manual.cs50.io/3/difftime) - calculate time difference - [dysize](https://manual.cs50.io/3/dysize) - get number of days for a given year - [getdate](https://manual.cs50.io/3/getdate) - convert a date-plus-time string to broken-down time - [getdate\_err](https://manual.cs50.io/3/getdate_err) - convert a date-plus-time string to broken-down time - [getdate\_r](https://manual.cs50.io/3/getdate_r) - convert a date-plus-time string to broken-down time - [gmtime](https://manual.cs50.io/3/gmtime) - transform date and time to broken-down time or ASCII - [gmtime\_r](https://manual.cs50.io/3/gmtime_r) - transform date and time to broken-down time or ASCII - [localtime](https://manual.cs50.io/3/localtime) - transform date and time to broken-down time or ASCII - [localtime\_r](https://manual.cs50.io/3/localtime_r) - transform date and time to broken-down time or ASCII - [mktime](https://manual.cs50.io/3/mktime) - transform date and time to broken-down time or ASCII - [nanosleep](https://manual.cs50.io/2/nanosleep) - high-resolution sleep - [stime](https://manual.cs50.io/2/stime) - set time - [strftime](https://manual.cs50.io/3/strftime) - format date and time - [strftime\_l](https://manual.cs50.io/3/strftime_l) - format date and time - [strptime](https://manual.cs50.io/3/strptime) - convert a string representation of time to a time tm s... - [time](https://manual.cs50.io/2/time) - get time in seconds get time in seconds - [timegm](https://manual.cs50.io/3/timegm) - inverses of gmtime and localtime - [timelocal](https://manual.cs50.io/3/timelocal) - inverses of gmtime and localtime - [timer\_create](https://manual.cs50.io/2/timer_create) - create a POSIX per-process timer - [timer\_delete](https://manual.cs50.io/2/timer_delete) - delete a POSIX per-process timer - [timer\_getoverrun](https://manual.cs50.io/2/timer_getoverrun) - get overrun count for a POSIX per-process timer - [timer\_gettime](https://manual.cs50.io/2/timer_gettime) - arm/disarm and fetch state of POSIX per-process timer - [timer\_settime](https://manual.cs50.io/2/timer_settime) - arm/disarm and fetch state of POSIX per-process timer - [timezone](https://manual.cs50.io/3/timezone) - initialize time conversion information - [tzname](https://manual.cs50.io/3/tzname) - initialize time conversion information - [tzset](https://manual.cs50.io/3/tzset) - initialize time conversion information ## [ulimit.h](https://manual.cs50.io/#ulimit.h) - [ulimit](https://manual.cs50.io/3/ulimit) - get and set user limits ## [unistd.h](https://manual.cs50.io/#unistd.h) - [\_Exit](https://manual.cs50.io/2/_Exit) - terminate the calling process - [\_exit](https://manual.cs50.io/2/_exit) - terminate the calling process - [\_llseek](https://manual.cs50.io/2/_llseek) - reposition read/write file offset - [\_sysctl](https://manual.cs50.io/2/_sysctl) - read/write system parameters - [access](https://manual.cs50.io/2/access) - check user's permissions for a file - [acct](https://manual.cs50.io/2/acct) - switch process accounting on or off - [alarm](https://manual.cs50.io/2/alarm) - set an alarm clock for delivery of a signal - [arch\_prctl](https://manual.cs50.io/2/arch_prctl) - set architecture-specific thread state - [brk](https://manual.cs50.io/2/brk) - change data segment size - [capget](https://manual.cs50.io/2/capget) - set/get capabilities of thread(s) - [capset](https://manual.cs50.io/2/capset) - set/get capabilities of thread(s) - [chdir](https://manual.cs50.io/2/chdir) - change working directory - [chown](https://manual.cs50.io/2/chown) - change ownership of a file - [chown32](https://manual.cs50.io/2/chown32) - change ownership of a file - [chroot](https://manual.cs50.io/2/chroot) - change root directory - [close](https://manual.cs50.io/2/close) - close a file descriptor - [close\_range](https://manual.cs50.io/2/close_range) - close all file descriptors in a given range - [confstr](https://manual.cs50.io/3/confstr) - get configuration dependent string variables - [copy\_file\_range](https://manual.cs50.io/2/copy_file_range) - Copy a range of data from one file to another - [cuserid](https://manual.cs50.io/3/cuserid) - get username - [daemon](https://manual.cs50.io/3/daemon) - run in the background - [delete\_module](https://manual.cs50.io/2/delete_module) - unload a kernel module - [dup](https://manual.cs50.io/2/dup) - duplicate a file descriptor - [dup2](https://manual.cs50.io/2/dup2) - duplicate a file descriptor - [dup3](https://manual.cs50.io/2/dup3) - duplicate a file descriptor - [eaccess](https://manual.cs50.io/3/eaccess) - check effective user's permissions for a file - [encrypt](https://manual.cs50.io/3/encrypt) - encrypt 64-bit messages - [encrypt\_r](https://manual.cs50.io/3/encrypt_r) - encrypt 64-bit messages - [endusershell](https://manual.cs50.io/3/endusershell) - get permitted user shells - [euidaccess](https://manual.cs50.io/3/euidaccess) - check effective user's permissions for a file - [exec](https://manual.cs50.io/3/exec) - execute a file - [execl](https://manual.cs50.io/3/execl) - execute a file - [execle](https://manual.cs50.io/3/execle) - execute a file - [execlp](https://manual.cs50.io/3/execlp) - execute a file - [execv](https://manual.cs50.io/3/execv) - execute a file - [execve](https://manual.cs50.io/2/execve) - execute program - [execveat](https://manual.cs50.io/2/execveat) - execute program relative to a directory file descriptor - [execvp](https://manual.cs50.io/3/execvp) - execute a file - [execvpe](https://manual.cs50.io/3/execvpe) - execute a file - [exit](https://manual.cs50.io/2/exit) - terminate the calling process - [exit\_group](https://manual.cs50.io/2/exit_group) - exit all threads in a process - [faccessat](https://manual.cs50.io/2/faccessat) - check user's permissions for a file - [faccessat2](https://manual.cs50.io/2/faccessat2) - check user's permissions for a file - [fchdir](https://manual.cs50.io/2/fchdir) - change working directory - [fchown](https://manual.cs50.io/2/fchown) - change ownership of a file - [fchown32](https://manual.cs50.io/2/fchown32) - change ownership of a file - [fchownat](https://manual.cs50.io/2/fchownat) - change ownership of a file - [fdatasync](https://manual.cs50.io/2/fdatasync) - synchronize a file's in-core state with storage device - [fexecve](https://manual.cs50.io/3/fexecve) - execute program specified via file descriptor - [finit\_module](https://manual.cs50.io/2/finit_module) - load a kernel module - [fork](https://manual.cs50.io/2/fork) - create a child process - [fpathconf](https://manual.cs50.io/3/fpathconf) - get configuration values for files - [fsync](https://manual.cs50.io/2/fsync) - synchronize a file's in-core state with storage device - [ftruncate](https://manual.cs50.io/2/ftruncate) - truncate a file to a specified length - [ftruncate64](https://manual.cs50.io/2/ftruncate64) - truncate a file to a specified length - [futex](https://manual.cs50.io/2/futex) - fast user-space locking - [get\_current\_dir\_name](https://manual.cs50.io/3/get_current_dir_name) - get current working directory - [get\_robust\_list](https://manual.cs50.io/2/get_robust_list) - get/set list of robust futexes - [get\_thread\_area](https://manual.cs50.io/2/get_thread_area) - manipulate thread-local storage information - [getcwd](https://manual.cs50.io/2/getcwd) - get current working directory - [getcwd](https://manual.cs50.io/3/getcwd) - get current working directory - [getdents](https://manual.cs50.io/2/getdents) - get directory entries - [getdents64](https://manual.cs50.io/2/getdents64) - get directory entries - [getdomainname](https://manual.cs50.io/2/getdomainname) - get/set NIS domain name - [getdtablesize](https://manual.cs50.io/3/getdtablesize) - get file descriptor table size - [getegid](https://manual.cs50.io/2/getegid) - get group identity - [getegid32](https://manual.cs50.io/2/getegid32) - get group identity - [getentropy](https://manual.cs50.io/3/getentropy) - fill a buffer with random bytes - [geteuid](https://manual.cs50.io/2/geteuid) - get user identity - [geteuid32](https://manual.cs50.io/2/geteuid32) - get user identity - [getgid](https://manual.cs50.io/2/getgid) - get group identity - [getgid32](https://manual.cs50.io/2/getgid32) - get group identity - [getgroups](https://manual.cs50.io/2/getgroups) - get/set list of supplementary group IDs - [getgroups32](https://manual.cs50.io/2/getgroups32) - get/set list of supplementary group IDs - [gethostid](https://manual.cs50.io/3/gethostid) - get or set the unique identifier of the current host - [gethostname](https://manual.cs50.io/2/gethostname) - get/set hostname - [getlogin](https://manual.cs50.io/3/getlogin) - get username - [getlogin\_r](https://manual.cs50.io/3/getlogin_r) - get username - [getopt](https://manual.cs50.io/3/getopt) - Parse command-line options - [getopt\_long](https://manual.cs50.io/3/getopt_long) - Parse command-line options - [getopt\_long\_only](https://manual.cs50.io/3/getopt_long_only) - Parse command-line options - [getpagesize](https://manual.cs50.io/2/getpagesize) - get memory page size - [getpass](https://manual.cs50.io/3/getpass) - get a password - [getpgid](https://manual.cs50.io/2/getpgid) - set/get process group - [getpgrp](https://manual.cs50.io/2/getpgrp) - set/get process group - [getpid](https://manual.cs50.io/2/getpid) - get process identification - [getppid](https://manual.cs50.io/2/getppid) - get process identification - [getresgid](https://manual.cs50.io/2/getresgid) - get real, effective, and saved user/group IDs - [getresgid32](https://manual.cs50.io/2/getresgid32) - get real, effective, and saved user/group IDs - [getresuid](https://manual.cs50.io/2/getresuid) - get real, effective, and saved user/group IDs - [getresuid32](https://manual.cs50.io/2/getresuid32) - get real, effective, and saved user/group IDs - [getsid](https://manual.cs50.io/2/getsid) - get session ID - [gettid](https://manual.cs50.io/2/gettid) - get thread identification - [getuid](https://manual.cs50.io/2/getuid) - get user identity - [getuid32](https://manual.cs50.io/2/getuid32) - get user identity - [getusershell](https://manual.cs50.io/3/getusershell) - get permitted user shells - [getwd](https://manual.cs50.io/3/getwd) - get current working directory - [group\_member](https://manual.cs50.io/3/group_member) - test whether a process is in a group - [idle](https://manual.cs50.io/2/idle) - make process 0 idle - [init\_module](https://manual.cs50.io/2/init_module) - load a kernel module - [io\_cancel](https://manual.cs50.io/2/io_cancel) - cancel an outstanding asynchronous I/O operation - [io\_destroy](https://manual.cs50.io/2/io_destroy) - destroy an asynchronous I/O context - [io\_getevents](https://manual.cs50.io/2/io_getevents) - read asynchronous I/O events from the completion queue - [ioprio\_get](https://manual.cs50.io/2/ioprio_get) - get/set I/O scheduling class and priority - [ioprio\_set](https://manual.cs50.io/2/ioprio_set) - get/set I/O scheduling class and priority - [ipc](https://manual.cs50.io/2/ipc) - System V IPC system calls - [isatty](https://manual.cs50.io/3/isatty) - test whether a file descriptor refers to a terminal - [kcmp](https://manual.cs50.io/2/kcmp) - compare two processes to determine if they share a ker... - [kexec\_file\_load](https://manual.cs50.io/2/kexec_file_load) - load a new kernel for later execution - [kexec\_load](https://manual.cs50.io/2/kexec_load) - load a new kernel for later execution - [keyctl](https://manual.cs50.io/2/keyctl) - manipulate the kernel's key management facility - [klogctl](https://manual.cs50.io/3/klogctl) - read and/or clear kernel message ring buffer; set cons... - [lchown](https://manual.cs50.io/2/lchown) - change ownership of a file - [lchown32](https://manual.cs50.io/2/lchown32) - change ownership of a file - [link](https://manual.cs50.io/2/link) - make a new name for a file - [linkat](https://manual.cs50.io/2/linkat) - make a new name for a file - [llseek](https://manual.cs50.io/2/llseek) - reposition read/write file offset - [lockf](https://manual.cs50.io/3/lockf) - apply, test or remove a POSIX lock on an open file - [lookup\_dcookie](https://manual.cs50.io/2/lookup_dcookie) - return a directory entry's path - [lseek](https://manual.cs50.io/2/lseek) - reposition read/write file offset - [membarrier](https://manual.cs50.io/2/membarrier) - issue memory barriers on a set of threads - [memfd\_secret](https://manual.cs50.io/2/memfd_secret) - create an anonymous RAM-based file to access secret me... - [mmap2](https://manual.cs50.io/2/mmap2) - map files or devices into memory - [modify\_ldt](https://manual.cs50.io/2/modify_ldt) - get or set a per-process LDT entry - [mount\_setattr](https://manual.cs50.io/2/mount_setattr) - change properties of a mount or mount tree - [mq\_getsetattr](https://manual.cs50.io/2/mq_getsetattr) - get/set message queue attributes - [nice](https://manual.cs50.io/2/nice) - change process priority - [openat2](https://manual.cs50.io/2/openat2) - open and possibly create a file (extended) - [optarg](https://manual.cs50.io/3/optarg) - Parse command-line options - [opterr](https://manual.cs50.io/3/opterr) - Parse command-line options - [optind](https://manual.cs50.io/3/optind) - Parse command-line options - [optopt](https://manual.cs50.io/3/optopt) - Parse command-line options - [pathconf](https://manual.cs50.io/3/pathconf) - get configuration values for files - [pause](https://manual.cs50.io/2/pause) - wait for signal - [perf\_event\_open](https://manual.cs50.io/2/perf_event_open) - set up performance monitoring - [pidfd\_getfd](https://manual.cs50.io/2/pidfd_getfd) - obtain a duplicate of another process's file descriptor - [pidfd\_open](https://manual.cs50.io/2/pidfd_open) - obtain a file descriptor that refers to a process - [pidfd\_send\_signal](https://manual.cs50.io/2/pidfd_send_signal) - send a signal to a process specified by a file descri... - [pipe](https://manual.cs50.io/2/pipe) - create pipe - [pipe2](https://manual.cs50.io/2/pipe2) - create pipe - [pivot\_root](https://manual.cs50.io/2/pivot_root) - change the root mount - [pread](https://manual.cs50.io/2/pread) - read from or write to a file descriptor at a given offset - [pread64](https://manual.cs50.io/2/pread64) - read from or write to a file descriptor at a given offset - [profil](https://manual.cs50.io/3/profil) - execution time profile - [pwrite](https://manual.cs50.io/2/pwrite) - read from or write to a file descriptor at a given offset - [pwrite64](https://manual.cs50.io/2/pwrite64) - read from or write to a file descriptor at a given offset - [read](https://manual.cs50.io/2/read) - read from a file descriptor - [readdir](https://manual.cs50.io/2/readdir) - read directory entry - [readlink](https://manual.cs50.io/2/readlink) - read value of a symbolic link - [readlinkat](https://manual.cs50.io/2/readlinkat) - read value of a symbolic link - [reboot](https://manual.cs50.io/2/reboot) - reboot or enable/disable Ctrl-Alt-Del - [rmdir](https://manual.cs50.io/2/rmdir) - delete a directory - [rt\_sigqueueinfo](https://manual.cs50.io/2/rt_sigqueueinfo) - queue a signal and data - [rt\_tgsigqueueinfo](https://manual.cs50.io/2/rt_tgsigqueueinfo) - queue a signal and data - [s390\_guarded\_storage](https://manual.cs50.io/2/s390_guarded_storage) - operations with z/Architecture guarded storage fac... - [s390\_pci\_mmio\_read](https://manual.cs50.io/2/s390_pci_mmio_read) - transfer data to/from PCI MMIO memory page - [s390\_pci\_mmio\_write](https://manual.cs50.io/2/s390_pci_mmio_write) - transfer data to/from PCI MMIO memory page - [s390\_runtime\_instr](https://manual.cs50.io/2/s390_runtime_instr) - enable/disable s390 CPU run-time instrumentation - [s390\_sthyi](https://manual.cs50.io/2/s390_sthyi) - emulate STHYI instruction - [sbrk](https://manual.cs50.io/2/sbrk) - change data segment size - [sched\_getattr](https://manual.cs50.io/2/sched_getattr) - set and get scheduling policy and attributes - [sched\_setattr](https://manual.cs50.io/2/sched_setattr) - set and get scheduling policy and attributes - [seccomp](https://manual.cs50.io/2/seccomp) - operate on Secure Computing state of the process - [set\_robust\_list](https://manual.cs50.io/2/set_robust_list) - get/set list of robust futexes - [set\_thread\_area](https://manual.cs50.io/2/set_thread_area) - manipulate thread-local storage information - [set\_tid\_address](https://manual.cs50.io/2/set_tid_address) - set pointer to thread ID - [setdomainname](https://manual.cs50.io/2/setdomainname) - get/set NIS domain name - [setegid](https://manual.cs50.io/2/setegid) - set effective user or group ID - [seteuid](https://manual.cs50.io/2/seteuid) - set effective user or group ID - [setgid](https://manual.cs50.io/2/setgid) - set group identity - [setgid32](https://manual.cs50.io/2/setgid32) - set group identity - [setgroups](https://manual.cs50.io/2/setgroups) - get/set list of supplementary group IDs - [setgroups32](https://manual.cs50.io/2/setgroups32) - get/set list of supplementary group IDs - [sethostid](https://manual.cs50.io/3/sethostid) - get or set the unique identifier of the current host - [sethostname](https://manual.cs50.io/2/sethostname) - get/set hostname - [setkey](https://manual.cs50.io/3/setkey) - encrypt 64-bit messages - [setkey\_r](https://manual.cs50.io/3/setkey_r) - encrypt 64-bit messages - [setpgid](https://manual.cs50.io/2/setpgid) - set/get process group - [setpgrp](https://manual.cs50.io/2/setpgrp) - set/get process group - [setregid](https://manual.cs50.io/2/setregid) - set real and/or effective user or group ID - [setregid32](https://manual.cs50.io/2/setregid32) - set real and/or effective user or group ID - [setresgid](https://manual.cs50.io/2/setresgid) - set real, effective, and saved user or group ID - [setresgid32](https://manual.cs50.io/2/setresgid32) - set real, effective, and saved user or group ID - [setresuid](https://manual.cs50.io/2/setresuid) - set real, effective, and saved user or group ID - [setresuid32](https://manual.cs50.io/2/setresuid32) - set real, effective, and saved user or group ID - [setreuid](https://manual.cs50.io/2/setreuid) - set real and/or effective user or group ID - [setreuid32](https://manual.cs50.io/2/setreuid32) - set real and/or effective user or group ID - [setsid](https://manual.cs50.io/2/setsid) - creates a session and sets the process group ID - [setuid](https://manual.cs50.io/2/setuid) - set user identity - [setuid32](https://manual.cs50.io/2/setuid32) - set user identity - [setup](https://manual.cs50.io/2/setup) - setup devices and filesystems, mount root filesystem - [setusershell](https://manual.cs50.io/3/setusershell) - get permitted user shells - [sgetmask](https://manual.cs50.io/2/sgetmask) - manipulation of signal mask (obsolete) - [sleep](https://manual.cs50.io/3/sleep) - sleep for a specified number of seconds - [socketcall](https://manual.cs50.io/2/socketcall) - socket system calls - [spu\_create](https://manual.cs50.io/2/spu_create) - create a new spu context - [spu\_run](https://manual.cs50.io/2/spu_run) - execute an SPU context - [ssetmask](https://manual.cs50.io/2/ssetmask) - manipulation of signal mask (obsolete) - [subpage\_prot](https://manual.cs50.io/2/subpage_prot) - define a subpage protection for an address range - [swab](https://manual.cs50.io/3/swab) - swap adjacent bytes - [symlink](https://manual.cs50.io/2/symlink) - make a new name for a file - [symlinkat](https://manual.cs50.io/2/symlinkat) - make a new name for a file - [sync](https://manual.cs50.io/2/sync) - commit filesystem caches to disk - [syncfs](https://manual.cs50.io/2/syncfs) - commit filesystem caches to disk - [syscall](https://manual.cs50.io/2/syscall) - indirect system call - [sysconf](https://manual.cs50.io/3/sysconf) - get configuration information at run time - [sysctl](https://manual.cs50.io/2/sysctl) - read/write system parameters - [syslog](https://manual.cs50.io/2/syslog) - read and/or clear kernel message ring buffer; set cons... - [tcgetpgrp](https://manual.cs50.io/3/tcgetpgrp) - get and set terminal foreground process group - [tcsetpgrp](https://manual.cs50.io/3/tcsetpgrp) - get and set terminal foreground process group - [tgkill](https://manual.cs50.io/2/tgkill) - send a signal to a thread - [tkill](https://manual.cs50.io/2/tkill) - send a signal to a thread - [truncate](https://manual.cs50.io/2/truncate) - truncate a file to a specified length - [truncate64](https://manual.cs50.io/2/truncate64) - truncate a file to a specified length - [ttyname](https://manual.cs50.io/3/ttyname) - return name of a terminal - [ttyname\_r](https://manual.cs50.io/3/ttyname_r) - return name of a terminal - [ualarm](https://manual.cs50.io/3/ualarm) - schedule signal after given number of microseconds - [unlink](https://manual.cs50.io/2/unlink) - delete a name and possibly the file it refers to - [unlinkat](https://manual.cs50.io/2/unlinkat) - delete a name and possibly the file it refers to - [uselib](https://manual.cs50.io/2/uselib) - load shared library - [userfaultfd](https://manual.cs50.io/2/userfaultfd) - create a file descriptor for handling page faults in u... - [usleep](https://manual.cs50.io/3/usleep) - suspend execution for microsecond intervals - [vfork](https://manual.cs50.io/2/vfork) - create a child process and block parent - [vhangup](https://manual.cs50.io/2/vhangup) - virtually hangup the current terminal - [write](https://manual.cs50.io/2/write) - write to a file descriptor ## [utime.h](https://manual.cs50.io/#utime.h) - [utime](https://manual.cs50.io/2/utime) - change file last access and modification times - [utimes](https://manual.cs50.io/2/utimes) - change file last access and modification times ## [utmpx.h](https://manual.cs50.io/#utmpx.h) - [getutmp](https://manual.cs50.io/3/getutmp) - copy utmp structure to utmpx, and vice versa - [getutmpx](https://manual.cs50.io/3/getutmpx) - copy utmp structure to utmpx, and vice versa ## [wchar.h](https://manual.cs50.io/#wchar.h) - [btowc](https://manual.cs50.io/3/btowc) - convert single byte to wide character - [fgetws](https://manual.cs50.io/3/fgetws) - read a wide-character string from a FILE stream - [fputws](https://manual.cs50.io/3/fputws) - write a wide-character string to a FILE stream - [fwide](https://manual.cs50.io/3/fwide) - set and determine the orientation of a FILE stream - [getwchar](https://manual.cs50.io/3/getwchar) - read a wide character from standard input - [mbrlen](https://manual.cs50.io/3/mbrlen) - determine number of bytes in next multibyte character - [mbrtowc](https://manual.cs50.io/3/mbrtowc) - convert a multibyte sequence to a wide character - [mbsinit](https://manual.cs50.io/3/mbsinit) - test for initial shift state - [mbsnrtowcs](https://manual.cs50.io/3/mbsnrtowcs) - convert a multibyte string to a wide-character string - [mbsrtowcs](https://manual.cs50.io/3/mbsrtowcs) - convert a multibyte string to a wide-character string ... - [putwchar](https://manual.cs50.io/3/putwchar) - write a wide character to standard output - [ungetwc](https://manual.cs50.io/3/ungetwc) - push back a wide character onto a FILE stream - [wcpcpy](https://manual.cs50.io/3/wcpcpy) - copy a wide-character string, returning a pointer to i... - [wcpncpy](https://manual.cs50.io/3/wcpncpy) - copy a fixed-size string of wide characters, returning... - [wcrtomb](https://manual.cs50.io/3/wcrtomb) - convert a wide character to a multibyte sequence - [wcscasecmp](https://manual.cs50.io/3/wcscasecmp) - compare two wide-character strings, ignoring case - [wcscat](https://manual.cs50.io/3/wcscat) - concatenate two wide-character strings - [wcschr](https://manual.cs50.io/3/wcschr) - search a wide character in a wide-character string - [wcscmp](https://manual.cs50.io/3/wcscmp) - compare two wide-character strings - [wcscpy](https://manual.cs50.io/3/wcscpy) - copy a wide-character string - [wcscspn](https://manual.cs50.io/3/wcscspn) - search a wide-character string for any of a set of wid... - [wcsdup](https://manual.cs50.io/3/wcsdup) - duplicate a wide-character string - [wcslen](https://manual.cs50.io/3/wcslen) - determine the length of a wide-character string - [wcsncasecmp](https://manual.cs50.io/3/wcsncasecmp) - compare two fixed-size wide-character strings, ignorin... - [wcsncat](https://manual.cs50.io/3/wcsncat) - concatenate two wide-character strings - [wcsncmp](https://manual.cs50.io/3/wcsncmp) - compare two fixed-size wide-character strings - [wcsncpy](https://manual.cs50.io/3/wcsncpy) - copy a fixed-size string of wide characters - [wcsnlen](https://manual.cs50.io/3/wcsnlen) - determine the length of a fixed-size wide-character st... - [wcsnrtombs](https://manual.cs50.io/3/wcsnrtombs) - convert a wide-character string to a multibyte string - [wcspbrk](https://manual.cs50.io/3/wcspbrk) - search a wide-character string for any of a set of wid... - [wcsrchr](https://manual.cs50.io/3/wcsrchr) - search a wide character in a wide-character string - [wcsrtombs](https://manual.cs50.io/3/wcsrtombs) - convert a wide-character string to a multibyte string - [wcsspn](https://manual.cs50.io/3/wcsspn) - get length of a prefix wide-character substring - [wcsstr](https://manual.cs50.io/3/wcsstr) - locate a substring in a wide-character string - [wcstok](https://manual.cs50.io/3/wcstok) - split wide-character string into tokens - [wcswidth](https://manual.cs50.io/3/wcswidth) - determine columns needed for a fixed-size wide-charact... - [wctob](https://manual.cs50.io/3/wctob) - try to represent a wide character as a single byte - [wcwidth](https://manual.cs50.io/3/wcwidth) - determine columns needed for a wide character - [wmemchr](https://manual.cs50.io/3/wmemchr) - search a wide character in a wide-character array - [wmemcmp](https://manual.cs50.io/3/wmemcmp) - compare two arrays of wide-characters - [wmemcpy](https://manual.cs50.io/3/wmemcpy) - copy an array of wide-characters - [wmemmove](https://manual.cs50.io/3/wmemmove) - copy an array of wide-characters - [wmemset](https://manual.cs50.io/3/wmemset) - fill an array of wide-characters with a constant wide ... ## [wctype.h](https://manual.cs50.io/#wctype.h) - [iswalnum](https://manual.cs50.io/3/iswalnum) - test for alphanumeric wide character - [iswalpha](https://manual.cs50.io/3/iswalpha) - test for alphabetic wide character - [iswblank](https://manual.cs50.io/3/iswblank) - test for whitespace wide character - [iswcntrl](https://manual.cs50.io/3/iswcntrl) - test for control wide character - [iswctype](https://manual.cs50.io/3/iswctype) - wide-character classification - [iswdigit](https://manual.cs50.io/3/iswdigit) - test for decimal digit wide character - [iswgraph](https://manual.cs50.io/3/iswgraph) - test for graphic wide character - [iswlower](https://manual.cs50.io/3/iswlower) - test for lowercase wide character - [iswprint](https://manual.cs50.io/3/iswprint) - test for printing wide character - [iswpunct](https://manual.cs50.io/3/iswpunct) - test for punctuation or symbolic wide character - [iswspace](https://manual.cs50.io/3/iswspace) - test for whitespace wide character - [iswupper](https://manual.cs50.io/3/iswupper) - test for uppercase wide character - [iswxdigit](https://manual.cs50.io/3/iswxdigit) - test for hexadecimal digit wide character - [towctrans](https://manual.cs50.io/3/towctrans) - wide-character transliteration - [towlower](https://manual.cs50.io/3/towlower) - convert a wide character to lowercase - [towlower\_l](https://manual.cs50.io/3/towlower_l) - convert a wide character to lowercase - [towupper](https://manual.cs50.io/3/towupper) - convert a wide character to uppercase - [towupper\_l](https://manual.cs50.io/3/towupper_l) - convert a wide character to uppercase - [wctrans](https://manual.cs50.io/3/wctrans) - wide-character translation mapping - [wctype](https://manual.cs50.io/3/wctype) - wide-character classification ## [wordexp.h](https://manual.cs50.io/#wordexp.h) - [wordexp](https://manual.cs50.io/3/wordexp) - perform word expansion like a posix-shell - [wordfree](https://manual.cs50.io/3/wordfree) - perform word expansion like a posix-shell
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