devdocs/c/atomic%2Fatomic_flag.html


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    <h1 id="firstHeading" class="firstHeading">atomic_flag</h1>            <table class="t-dcl-begin"> <tr class="t-dsc-header"> <th> Defined in header <code>&lt;stdatomic.h&gt;</code> </th> <th> </th> <th> </th> </tr> <tr class="t-dcl t-since-c11"> <td> <pre data-language="c">struct atomic_flag;</pre>
</td> <td class="t-dcl-nopad"> </td> <td> <span class="t-mark-rev t-since-c11">(since C11)</span> </td> </tr>  </table> <p><code>atomic_flag</code> is an atomic boolean type. Unlike other atomic types, it is guaranteed to be lock-free. Unlike <a href="../thread#Atomic_operations" title="c/thread"><code>atomic_bool</code></a>, <code>atomic_flag</code> does not provide load or store operations.</p>
<h3 id="References"> References</h3>  <ul>
<li> C17 standard (ISO/IEC 9899:2018): </li>
<ul>
<li> 7.17.1/4 atomic_flag (p: 200) </li>
<li> 7.17.8 Atomic flag type and operations (p: 208-209) </li>
</ul>
<li> C11 standard (ISO/IEC 9899:2011): </li>
<ul>
<li> 7.17.1/4 atomic_flag (p: 273) </li>
<li> 7.17.8 Atomic flag type and operations (p: 285-286) </li>
</ul>
</ul>         <h3 id="See_also"> See also</h3> <table class="t-dsc-begin"> <tr class="t-dsc"> <td> <div><a href="atomic_flag_init" title="c/atomic/ATOMIC FLAG INIT"> <span class="t-lines"><span>ATOMIC_FLAG_INIT</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> initializes a new <code>atomic_flag</code> <br> <span class="t-mark">(macro constant)</span>  </td>
</tr> <tr class="t-dsc"> <td> <div><a href="atomic_flag_test_and_set" title="c/atomic/atomic flag test and set"> <span class="t-lines"><span>atomic_flag_test_and_set</span><span>atomic_flag_test_and_set_explicit</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> sets an atomic_flag to true and returns the old value <br> <span class="t-mark">(function)</span>  </td>
</tr> <tr class="t-dsc"> <td> <div><a href="atomic_flag_clear" title="c/atomic/atomic flag clear"> <span class="t-lines"><span>atomic_flag_clear</span><span>atomic_flag_clear_explicit</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> sets an atomic_flag to false <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/atomic/atomic_flag" title="cpp/atomic/atomic flag">C++ documentation</a></span> for <code>atomic_flag</code> </td>
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