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# [ Boost C++ Libraries](https://www.boost.org/) "...one of the most highly regarded and expertly designed C++ library projects in the world." — [Herb Sutter](https://herbsutter.com/) and [Andrei Alexandrescu](http://en.wikipedia.org/wiki/Andrei_Alexandrescu), [C++ Coding Standards](https://books.google.com/books/about/C++_Coding_Standards.html?id=mmjVIC6WolgC) Search... This is an older version of Boost and was released in 2017. The [current version](https://www.boost.org/doc/libs/latest/doc/html/lockfree/examples.html) is 1.90.0. [](https://www.boost.org/doc/libs/1_65_0/doc/html/lockfree.html)[](https://www.boost.org/doc/libs/1_65_0/doc/html/lockfree.html)[](https://www.boost.org/doc/libs/1_65_0/doc/html/index.html)[](https://www.boost.org/doc/libs/1_65_0/doc/html/lockfree/rationale.html) ## [Examples](https://www.boost.org/doc/libs/1_65_0/doc/html/lockfree/examples.html "Examples") ### [Queue](https://www.boost.org/doc/libs/1_65_0/doc/html/lockfree/examples.html#lockfree.examples.queue) The `boost::lockfree::queue` class implements a multi-writer/multi-reader queue. The following example shows how integer values are produced and consumed by 4 threads each: ``` #include <boost/thread/thread.hpp> #include <boost/lockfree/queue.hpp> #include <iostream> #include <boost/atomic.hpp> boost::atomic_int producer_count(0); boost::atomic_int consumer_count(0); boost::lockfree::queue<int> queue(128); const int iterations = 10000000; const int producer_thread_count = 4; const int consumer_thread_count = 4; void producer(void) { for (int i = 0; i != iterations; ++i) { int value = ++producer_count; while (!queue.push(value)) ; } } boost::atomic<bool> done (false); void consumer(void) { int value; while (!done) { while (queue.pop(value)) ++consumer_count; } while (queue.pop(value)) ++consumer_count; } int main(int argc, char* argv[]) { using namespace std; cout << "boost::lockfree::queue is "; if (!queue.is_lock_free()) cout << "not "; cout << "lockfree" << endl; boost::thread_group producer_threads, consumer_threads; for (int i = 0; i != producer_thread_count; ++i) producer_threads.create_thread(producer); for (int i = 0; i != consumer_thread_count; ++i) consumer_threads.create_thread(consumer); producer_threads.join_all(); done = true; consumer_threads.join_all(); cout << "produced " << producer_count << " objects." << endl; cout << "consumed " << consumer_count << " objects." << endl; } ``` The program output is: ``` produced 40000000 objects. consumed 40000000 objects. ``` ### [Stack](https://www.boost.org/doc/libs/1_65_0/doc/html/lockfree/examples.html#lockfree.examples.stack) The `boost::lockfree::stack` class implements a multi-writer/multi-reader stack. The following example shows how integer values are produced and consumed by 4 threads each: ``` #include <boost/thread/thread.hpp> #include <boost/lockfree/stack.hpp> #include <iostream> #include <boost/atomic.hpp> boost::atomic_int producer_count(0); boost::atomic_int consumer_count(0); boost::lockfree::stack<int> stack(128); const int iterations = 1000000; const int producer_thread_count = 4; const int consumer_thread_count = 4; void producer(void) { for (int i = 0; i != iterations; ++i) { int value = ++producer_count; while (!stack.push(value)) ; } } boost::atomic<bool> done (false); void consumer(void) { int value; while (!done) { while (stack.pop(value)) ++consumer_count; } while (stack.pop(value)) ++consumer_count; } int main(int argc, char* argv[]) { using namespace std; cout << "boost::lockfree::stack is "; if (!stack.is_lock_free()) cout << "not "; cout << "lockfree" << endl; boost::thread_group producer_threads, consumer_threads; for (int i = 0; i != producer_thread_count; ++i) producer_threads.create_thread(producer); for (int i = 0; i != consumer_thread_count; ++i) consumer_threads.create_thread(consumer); producer_threads.join_all(); done = true; consumer_threads.join_all(); cout << "produced " << producer_count << " objects." << endl; cout << "consumed " << consumer_count << " objects." << endl; } ``` The program output is: ``` produced 4000000 objects. consumed 4000000 objects. ``` ### [Waitfree Single-Producer/Single-Consumer Queue](https://www.boost.org/doc/libs/1_65_0/doc/html/lockfree/examples.html#lockfree.examples.waitfree_single_producer_single_consumer_queue) The `boost::lockfree::spsc_queue` class implements a wait-free single-producer/single-consumer queue. The following example shows how integer values are produced and consumed by 2 separate threads: ``` #include <boost/thread/thread.hpp> #include <boost/lockfree/spsc_queue.hpp> #include <iostream> #include <boost/atomic.hpp> int producer_count = 0; boost::atomic_int consumer_count (0); boost::lockfree::spsc_queue<int, boost::lockfree::capacity<1024> > spsc_queue; const int iterations = 10000000; void producer(void) { for (int i = 0; i != iterations; ++i) { int value = ++producer_count; while (!spsc_queue.push(value)) ; } } boost::atomic<bool> done (false); void consumer(void) { int value; while (!done) { while (spsc_queue.pop(value)) ++consumer_count; } while (spsc_queue.pop(value)) ++consumer_count; } int main(int argc, char* argv[]) { using namespace std; cout << "boost::lockfree::queue is "; if (!spsc_queue.is_lock_free()) cout << "not "; cout << "lockfree" << endl; boost::thread producer_thread(producer); boost::thread consumer_thread(consumer); producer_thread.join(); done = true; consumer_thread.join(); cout << "produced " << producer_count << " objects." << endl; cout << "consumed " << consumer_count << " objects." << endl; } ``` The program output is: ``` produced 10000000 objects. consumed 10000000 objects. ``` | | | |---|---| | | Copyright © 2008-2011 Tim Blechmann Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE\_1\_0.txt or copy at <http://www.boost.org/LICENSE_1_0.txt>) | *** [](https://www.boost.org/doc/libs/1_65_0/doc/html/lockfree.html)[](https://www.boost.org/doc/libs/1_65_0/doc/html/lockfree.html)[](https://www.boost.org/doc/libs/1_65_0/doc/html/index.html)[](https://www.boost.org/doc/libs/1_65_0/doc/html/lockfree/rationale.html)