devdocs/c/thread%2Fmtx_trylock.html


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    <h1 id="firstHeading" class="firstHeading">mtx_trylock</h1>            <table class="t-dcl-begin"> <tr class="t-dsc-header"> <th> Defined in header <code>&lt;threads.h&gt;</code> </th> <th> </th> <th> </th> </tr> <tr class="t-dcl t-since-c11"> <td> <pre data-language="c">int mtx_trylock( mtx_t *mutex );</pre>
</td> <td class="t-dcl-nopad"> </td> <td> <span class="t-mark-rev t-since-c11">(since C11)</span> </td> </tr>  </table> <p>Tries to lock the mutex pointed to by <code>mutex</code> without blocking. Returns immediately if the mutex is already locked.</p>
<p>Prior calls to <code><a href="mtx_unlock" title="c/thread/mtx unlock">mtx_unlock</a></code> on the same mutex <i>synchronize-with</i> this operation (if this operation succeeds), and all lock/unlock operations on any given mutex form a single total order (similar to the modification order of an atomic)</p>
<h3 id="Parameters"> Parameters</h3> <table class="t-par-begin"> <tr class="t-par"> <td> mutex </td> <td> - </td> <td> pointer to the mutex to lock </td>
</tr>
</table> <h3 id="Return_value"> Return value</h3> <p><code><a href="thrd_errors" title="c/thread/thrd errors">thrd_success</a></code> if successful, <code><a href="thrd_errors" title="c/thread/thrd errors">thrd_busy</a></code> if the mutex has already been locked or due to a spurious failure to acquire an available mutex, <code><a href="thrd_errors" title="c/thread/thrd errors">thrd_error</a></code> if an error occurs.</p>
<h3 id="Defect_reports"> Defect reports</h3> <p>The following behavior-changing defect reports were applied retroactively to previously published C standards.</p>
<table class="dsctable"> <tr> <th>DR </th> <th>Applied to </th> <th>Behavior as published </th> <th>Correct behavior </th>
</tr> <tr> <td>
<a rel="nofollow" class="external text" href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2396.htm#dr_470">DR 470</a> </td> <td>C11 </td> <td>
<code>mtx_trylock</code> was not allowed to fail spuriously </td> <td>allowed </td>
</tr>
</table> <h3 id="References"> References</h3>  <ul>
<li> C17 standard (ISO/IEC 9899:2018): </li>
<ul><li> 7.26.4.5 The mtx_trylock function (p: 278-279) </li></ul>
<li> C11 standard (ISO/IEC 9899:2011): </li>
<ul><li> 7.26.4.5 The mtx_trylock function (p: 382) </li></ul>
</ul>       <h3 id="See_also"> See also</h3> <table class="t-dsc-begin"> <tr class="t-dsc"> <td> <div><a href="mtx_lock" title="c/thread/mtx lock"> <span class="t-lines"><span>mtx_lock</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c11">(C11)</span></span></span></div> </td> <td> blocks until locks a mutex <br> <span class="t-mark">(function)</span>  </td>
</tr> <tr class="t-dsc"> <td> <div><a href="mtx_timedlock" title="c/thread/mtx timedlock"> <span class="t-lines"><span>mtx_timedlock</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c11">(C11)</span></span></span></div> </td> <td> blocks until locks a mutex or times out <br> <span class="t-mark">(function)</span>  </td>
</tr> <tr class="t-dsc"> <td> <div><a href="mtx_unlock" title="c/thread/mtx unlock"> <span class="t-lines"><span>mtx_unlock</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c11">(C11)</span></span></span></div> </td> <td> unlocks a mutex <br> <span class="t-mark">(function)</span>  </td>
</tr> <tr class="t-dsc"> <td colspan="2"> <span><a href="https://en.cppreference.com/w/cpp/thread/mutex/try_lock" title="cpp/thread/mutex/try lock">C++ documentation</a></span> for <code>mutex::try_lock</code> </td>
</tr> <tr class="t-dsc"> <td colspan="2"> <span><a href="https://en.cppreference.com/w/cpp/thread/timed_mutex/try_lock" title="cpp/thread/timed mutex/try lock">C++ documentation</a></span> for <code>timed_mutex::try_lock</code> </td>
</tr> <tr class="t-dsc"> <td colspan="2"> <span><a href="https://en.cppreference.com/w/cpp/thread/recursive_mutex/try_lock" title="cpp/thread/recursive mutex/try lock">C++ documentation</a></span> for <code>recursive_mutex::try_lock</code> </td>
</tr> <tr class="t-dsc"> <td colspan="2"> <span><a href="https://en.cppreference.com/w/cpp/thread/recursive_timed_mutex/try_lock" title="cpp/thread/recursive timed mutex/try lock">C++ documentation</a></span> for <code>recursive_timed_mutex::try_lock</code> </td>
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