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| |
| <h1 align="center">mutex - Mutex</h1> |
| |
| <h2>Introduction</h2> |
| |
| <p>detail/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.</p> |
| |
| <h2>Configuration</h2> |
| |
| <p>This 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, <span class="code">#define |
| BOOST_NO_MT</span> before any inclusion of this header. To prevent ODR |
| violations, this should be defined in <strong>every</strong> translation |
| unit in your project, including any library files.</p> |
| |
| <h2>Synopsis</h2> |
| <pre class="code"> |
| namespace 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 |
| </pre> |
| |
| <h2>Semantics</h2> |
| |
| <table border align="center" summary=""> |
| <caption> |
| <em>Symbol Table</em> |
| </caption> |
| |
| <tr> |
| <th>Symbol</th> |
| |
| <th>Meaning</th> |
| </tr> |
| |
| <tr> |
| <td class="code">Mutex</td> |
| |
| <td>Any type defined in this header</td> |
| </tr> |
| |
| <tr> |
| <td class="code">t</td> |
| |
| <td>value of type <span class="code">Mutex</span></td> |
| </tr> |
| </table><br> |
| |
| <table border align="center" summary=""> |
| <caption> |
| <em>Requirements satisfied by <span class="code">mutex</span></em> |
| </caption> |
| |
| <tr> |
| <th>Expression</th> |
| |
| <th>Return Type</th> |
| |
| <th>Assertion/Note/Pre/Post-Condition</th> |
| </tr> |
| |
| <tr> |
| <td class="code">m.lock()</td> |
| |
| <td>not used</td> |
| |
| <td>Locks the mutex</td> |
| </tr> |
| |
| <tr> |
| <td class="code">m.unlock()</td> |
| |
| <td>not used</td> |
| |
| <td>Unlocks the mutex</td> |
| </tr> |
| </table> |
| |
| <p>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 <strong>must</strong> own the mutex to release that ownership!). As |
| a special case, the <span class="code">null_mutex</span> never waits.</p> |
| |
| <h2>Dependencies</h2> |
| |
| <p>May include the system headers <span class= |
| "code"><windows.h></span>, <span class= |
| "code"><unistd.h></span>, and/or <span class= |
| "code"><pthread.h></span>.</p> |
| |
| <h2>Future Directions</h2> |
| |
| <p>This header will eventually be replaced by a Boost multithreading |
| library.</p> |
| <hr> |
| |
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| |
| <p>Revised |
| <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B, %Y" startspan -->05 |
| December, 2006<!--webbot bot="Timestamp" endspan i-checksum="38516" --></p> |
| |
| <p><i>Copyright © 2000, 2001 Stephen Cleary (scleary AT jerviswebb DOT |
| com)</i></p> |
| |
| <p><i>Distributed under the Boost Software License, Version 1.0. (See |
| accompanying file <a href="../../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> |
| or copy at <a href= |
| "http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</a>)</i></p> |
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