mutex - MutexIntroductiondetail/mutex.hpp provides several mutex types that provide a consistent interface for OS-supplied mutex types. These are all thread-level mutexes; interprocess mutexes are not supported. ConfigurationThis header file will try to guess what kind of system it is on. It will auto-configure itself for Win32 or POSIX+pthread systems. To stub out all mutex code, bypassing the auto-configuration, #define BOOST_NO_MT before any inclusion of this header. To prevent ODR violations, this should be defined in every translation unit in your project, including any library files. Synopsisnamespace details { namespace pool { // Only present if on a Win32 system class Win32_mutex { private: Win32_mutex(const Win32_mutex &); void operator=(const Win32_mutex &); public: Win32_mutex(); ~Win32_mutex(); void lock(); void unlock(); }; // Only present if on a POSIX+pthread system class pthread_mutex { private: pthread_mutex(const pthread_mutex &); void operator=(const pthread_mutex &); public: pthread_mutex(); ~pthread_mutex(); void lock(); void unlock(); }; // Present on all systems class null_mutex { private: null_mutex(const null_mutex &); void operator=(const null_mutex &); public: null_mutex(); ~null_mutex(); static void lock(); static void unlock(); }; // This will be one of the types above typedef ... default_mutex; } // namespace pool } // namespace details Semantics
Each mutex is always either owned or unowned. If owned, then it is owned by a particular thread. To "lock" a mutex means to wait until the mutex is unowned, and then make it owned by the current thread. To "unlock" a mutex means to release ownership from the current thread (note that the current thread must own the mutex to release that ownership!). As a special case, the null_mutex never waits. DependenciesMay include the system headers <windows.h>, <unistd.h>, and/or <pthread.h>. Future DirectionsThis header will eventually be replaced by a Boost multithreading library. Revised 05 December, 2006 Copyright © 2000, 2001 Stephen Cleary (scleary AT jerviswebb DOT com) 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) |