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[All Manuals](https://www.lispworks.com/documentation/lw70/intro.htm) \> [LispWorks User Guide and Reference Manual](https://www.lispworks.com/documentation/lw70/LW/html/lw.htm) \> [19 Multiprocessing](https://www.lispworks.com/documentation/lw70/LW/html/lw-133.htm) [](https://www.lispworks.com/documentation/lw70/LW/html/lw-136.htm)[](https://www.lispworks.com/documentation/lw70/LW/html/lw-134.htm)[](https://www.lispworks.com/documentation/lw70/LW/html/lw-133.htm)[](https://www.lispworks.com/documentation/lw70/LW/html/lw.htm)[](https://www.lispworks.com/documentation/lw70/LW/html/lw-2.htm#pgfId-1819613)[](https://www.lispworks.com/documentation/lw70/LW/html/lw-1432.htm) ### 19\.2 Processes basics #### 19\.2.1 Creating a process To create a new process, use [process-run-function](https://www.lispworks.com/documentation/lw70/LW/html/lw-977.htm#96518). A process can exit either by returning from the process function or by calling [current-process-kill](https://www.lispworks.com/documentation/lw70/LW/html/lw-903.htm#13262). #### 19\.2.2 Finding out about processes The system initializes a number of processes on startup. These processes are specified by``[\*initial-processes\*](https://www.lispworks.com/documentation/lw70/LW/html/lw-918.htm#18630). The current process is obtained by [get-current-process](https://www.lispworks.com/documentation/lw70/LW/html/lw-914.htm#30865). A list of all the current processes is returned by [list-all-processes](https://www.lispworks.com/documentation/lw70/LW/html/lw-920.htm#55433) and the number of them is returned by [processes-count](https://www.lispworks.com/documentation/lw70/LW/html/lw-997.htm#44826). The function [ps](https://www.lispworks.com/documentation/lw70/LW/html/lw-1000.htm#43017) is analogous to the UNIX command `ps`, and returns a list of the processes in the system, ordered by priority. To find a process when you know its name, use [get-process](https://www.lispworks.com/documentation/lw70/LW/html/lw-915.htm#91897). To find the name, when you have the process, use [process-name](https://www.lispworks.com/documentation/lw70/LW/html/lw-969.htm#65666). The variable [\*process-initial-bindings\*](https://www.lispworks.com/documentation/lw70/LW/html/lw-961.htm#59591) specifies the variables that are initially bound in a process. #### 19\.2.3 Multiprocessing To start multiprocessing, use [initialize-multiprocessing](https://www.lispworks.com/documentation/lw70/LW/html/lw-917.htm#86604). This function does not return until multiprocessing has terminated. It is not necessary to use [initialize-multiprocessing](https://www.lispworks.com/documentation/lw70/LW/html/lw-917.htm#86604) when the LispWorks environment is already running. Note that, on Windows, Mac OS X, Linux, x86/x64 Solaris and FreeBSD, the LispWorks images shipped do start the programming environment. If you create an image which does not start the programming environment, by using the `:environment nil` argument to [save-image](https://www.lispworks.com/documentation/lw70/LW/html/lw-602.htm#36980), then multiprocessing can be started in this new image as described below. ##### 19\.2.3.1 Starting multiprocessing interactively You can call [initialize-multiprocessing](https://www.lispworks.com/documentation/lw70/LW/html/lw-917.htm#86604) from the REPL interface, which generates a default Listener process if no other processes are specified by [\*initial-processes\*](https://www.lispworks.com/documentation/lw70/LW/html/lw-918.htm#18630). ##### 19\.2.3.2 Multiprocessing on startup There are three ways to make a LispWorks executable start multiprocessing on startup. 1\. Use the `-multiprocessing` command line argument 2\. Save an image which starts multiprocessing by doing ``` (save-image "mp-lispworks" ``` ``` :restart-function 'mp:initialize-multiprocessing) ``` 3\. Use delivery to create the executable and pass the argument `:multiprocessing t` to [deliver](https://www.lispworks.com/documentation/lw70/LW/html/lw-690.htm#44253). The delivery function will be called automatically in a new process. See the *LispWorks Delivery User Guide* for more details. LispWorks dynamic libraries always start multiprocessing on startup. See [Multiprocessing in a dynamic library](https://www.lispworks.com/documentation/lw70/LW/html/lw-107.htm#49818) for more information. In all cases, [\*initial-processes\*](https://www.lispworks.com/documentation/lw70/LW/html/lw-918.htm#18630) can be used to control which processes are created on startup, as described in [Running your own processes on startup](https://www.lispworks.com/documentation/lw70/LW/html/lw-135.htm#56209). **Note:** On Windows, Linux, x86/x64 Solaris, FreeBSD and Mac OS X you cannot save a LispWorks image with multiprocessing running. ##### 19\.2.3.3 Running your own processes on startup [\*initial-processes\*](https://www.lispworks.com/documentation/lw70/LW/html/lw-918.htm#18630) is a list of lists. Each list is used by the system as a set of arguments to [process-run-function](https://www.lispworks.com/documentation/lw70/LW/html/lw-977.htm#96518). During initializing multiprocessing, the system does this: ``` (dolist (x mp:*initial-processes*) ``` ``` (apply 'mp:process-run-function x)) ``` This script saves a LispWorks image which starts multiprocessing on restart and runs a user-defined process. ``` (load-all-patches) ``` ``` (load "my-server-code") ``` ``` (push '("Start Server" () start-my-server) ``` ``` mp:*initial-processes*) ``` ``` (save-image "my-server" ``` ``` :remarks "My Server" ``` ``` :restart-function 'mp:initialize-multiprocessing ``` ``` :environment nil) ``` See [save-image](https://www.lispworks.com/documentation/lw70/LW/html/lw-602.htm#36980) for a description of how to save an image. *** *LispWorks User Guide and Reference Manual - 13 Feb 2015* [](https://www.lispworks.com/documentation/lw70/LW/html/lw-136.htm)[](https://www.lispworks.com/documentation/lw70/LW/html/lw-134.htm)[](https://www.lispworks.com/documentation/lw70/LW/html/lw-133.htm)[](https://www.lispworks.com/documentation/lw70/LW/html/lw.htm)[](https://www.lispworks.com/documentation/lw70/LW/html/lw-2.htm#pgfId-1819613)[](https://www.lispworks.com/documentation/lw70/LW/html/lw-1432.htm)