devdocs/c/atomic%2Fatomic_store.html


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    <h1 id="firstHeading" class="firstHeading">atomic_store, atomic_store_explicit</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">void atomic_store( volatile A* obj , C desired );</pre>
</td> <td> (1) </td> <td> <span class="t-mark-rev t-since-c11">(since C11)</span> </td> </tr> <tr class="t-dcl t-since-c11"> <td> <pre data-language="c">void atomic_store_explicit( volatile A* obj, C desired, memory_order order );</pre>
</td> <td> (2) </td> <td> <span class="t-mark-rev t-since-c11">(since C11)</span> </td> </tr>  </table> <p>Atomically replaces the value of the atomic variable pointed to by <code>obj</code> with <code>desired</code>. The operation is atomic write operation.</p>
<p>The first version orders memory accesses according to <code><a href="memory_order" title="c/atomic/memory order">memory_order_seq_cst</a></code>, the second version orders memory accesses according to <code>order</code>. <code>order</code> must be one of <code><a href="memory_order" title="c/atomic/memory order">memory_order_relaxed</a></code>, <code><a href="memory_order" title="c/atomic/memory order">memory_order_release</a></code> or <code><a href="memory_order" title="c/atomic/memory order">memory_order_seq_cst</a></code>. Otherwise the behavior is undefined.</p>
<p>This is a <a href="../language/generic" title="c/language/generic">generic function</a> defined for all <a href="../language/atomic" title="c/language/atomic">atomic object types</a> <code>A</code>. The argument is pointer to a volatile atomic type to accept addresses of both non-volatile and <a href="../language/volatile" title="c/language/volatile">volatile</a> (e.g. memory-mapped I/O) atomic objects, and volatile semantic is preserved when applying this operation to volatile atomic objects. <code>C</code> is the non-atomic type corresponding to <code>A</code>.</p>
<p>It is unspecified whether the name of a generic function is a macro or an identifier declared with external linkage. If a macro definition is suppressed in order to access an actual function (e.g. parenthesized like <code>(atomic_store)(...)</code>), or a program defines an external identifier with the name of a generic function, the behavior is undefined.</p>
<h3 id="Parameters"> Parameters</h3> <table class="t-par-begin"> <tr class="t-par"> <td> obj </td> <td> - </td> <td> pointer to the atomic object to modify </td>
</tr> <tr class="t-par"> <td> order </td> <td> - </td> <td> the memory synchronization ordering for this operation </td>
</tr>
</table> <h3 id="Return_value"> Return value</h3> <p>(none)</p>
<h3 id="References"> References</h3>  <ul>
<li> C17 standard (ISO/IEC 9899:2018): </li>
<ul><li> 7.17.7.1 The atomic_store generic functions (p: 206) </li></ul>
<li> C11 standard (ISO/IEC 9899:2011): </li>
<ul><li> 7.17.7.1 The atomic_store generic functions (p: 282) </li></ul>
</ul>       <h3 id="See_also"> See also</h3> <table class="t-dsc-begin"> <tr class="t-dsc"> <td> <div><a href="atomic_load" title="c/atomic/atomic load"> <span class="t-lines"><span>atomic_load</span><span>atomic_load_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> reads a value from an atomic object <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_store" title="cpp/atomic/atomic store">C++ documentation</a></span> for <code>atomic_store, atomic_store_explicit</code> </td>
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