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<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><strong class="selflink"><span class="t-lines"><span>atomic_weak_ptr::exchange</span></span></strong></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="compare_exchange.html" title="cpp/experimental/atomic weak ptr/compare exchange"><span class="t-lines"><span>atomic_weak_ptr::compare_exchange_weak</span><span>atomic_weak_ptr::compare_exchange_strong</span></span></a></div></div></td></tr>
</table></div><div><span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/experimental/concurrency/atomic_weak_ptr/navbar_content&action=edit">[edit]</a></span></div></div></div></div><div class="t-navbar-sep"> </div></div>
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<td class="t-dcl-nopad"> <div><span class="mw-geshi cpp source-cpp">weak_ptr<span class="sy1"><</span>T<span class="sy1">></span> exchange<span class="br0">(</span> weak_ptr<span class="sy1"><</span>T<span class="sy1">></span> desired, <a href="../../atomic/memory_order.html"><span class="kw2088">std::<span class="me2">memory_order</span></span></a> order <span class="sy1">=</span> <a href="../../atomic/memory_order.html"><span class="kw2094">std::<span class="me2">memory_order_seq_cst</span></span></a> <span class="br0">)</span><span class="sy4">;</span></span></div></td>
<td class="t-dcl-nopad"> </td>
<td class="t-dcl-nopad"> </td>
</tr>
<tr class="t-dcl-sep"><td></td><td></td><td></td></tr>
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<p>Atomically replaces the underlying <code>weak_ptr</code> with <code>desired</code>. The operation is a read-modify-write operation. Memory is affected according to the value of <code>order</code>.
</p>
<table id="toc" class="toc"><tr><td><div id="toctitle"><h2>Contents</h2></div>
<ul>
<li class="toclevel-1 tocsection-1"><a href="exchange.html#Parameters"><span class="tocnumber">1</span> <span class="toctext">Parameters</span></a></li>
<li class="toclevel-1 tocsection-2"><a href="exchange.html#Return_value"><span class="tocnumber">2</span> <span class="toctext">Return value</span></a></li>
<li class="toclevel-1 tocsection-3"><a href="exchange.html#Remarks"><span class="tocnumber">3</span> <span class="toctext">Remarks</span></a></li>
<li class="toclevel-1 tocsection-4"><a href="exchange.html#Exceptions"><span class="tocnumber">4</span> <span class="toctext">Exceptions</span></a></li>
<li class="toclevel-1 tocsection-5"><a href="exchange.html#See_also"><span class="tocnumber">5</span> <span class="toctext">See also</span></a></li>
</ul>
</td></tr></table>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/experimental/atomic_weak_ptr/exchange&action=edit&section=1" title="Edit section: Parameters">edit</a>]</span> <span class="mw-headline" id="Parameters">Parameters</span></h3>
<table class="t-par-begin">
<tr class="t-par">
<td> desired
</td>
<td> -
</td>
<td> value to assign
</td></tr>
<tr class="t-par">
<td> order
</td>
<td> -
</td>
<td> memory order constraints to enforce
</td></tr></table>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/experimental/atomic_weak_ptr/exchange&action=edit&section=2" title="Edit section: Return value">edit</a>]</span> <span class="mw-headline" id="Return_value">Return value</span></h3>
<p>The value of the atomic variable before the call.
</p>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/experimental/atomic_weak_ptr/exchange&action=edit&section=3" title="Edit section: Remarks">edit</a>]</span> <span class="mw-headline" id="Remarks">Remarks</span></h3>
<p>All changes to the <code>atomic_weak_ptr</code> object itself, and all associated <a href="../../memory/weak_ptr/use_count.html" title="cpp/memory/weak ptr/use count"><tt>use_count</tt></a> increments, are guaranteed to be performed atomically. Associated <code>use_count</code> decrements take place after the atomic operation, but are not required to be part of it. Any associated destruction or deallocation operations take place after the atomic operation and are not part of it.
</p>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/experimental/atomic_weak_ptr/exchange&action=edit&section=4" title="Edit section: Exceptions">edit</a>]</span> <span class="mw-headline" id="Exceptions">Exceptions</span></h3>
<div class="t-noexcept-inline"><a href="../../language/noexcept_spec.html" title="cpp/language/noexcept spec"><tt>noexcept</tt></a> specification:  <div class="t-noexcept-box"><span class="t-cc"><span class="mw-geshi cpp source-cpp"><span class="kw1">noexcept</span></span></span></div>  </div>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/experimental/atomic_weak_ptr/exchange&action=edit&section=5" title="Edit section: See also">edit</a>]</span> <span class="mw-headline" id="See_also">See also</span></h3>
<table class="t-dsc-begin">
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="../../memory/shared_ptr/atomic.html" title="cpp/memory/shared ptr/atomic"> <span class="t-lines"><span>std::atomic_is_lock_free<span class="t-dsc-small">(std::shared_ptr)</span></span><span>std::atomic_load<span class="t-dsc-small">(std::shared_ptr)</span></span><span>std::atomic_load_explicit<span class="t-dsc-small">(std::shared_ptr)</span></span><span>std::atomic_store<span class="t-dsc-small">(std::shared_ptr)</span></span><span>std::atomic_store_explicit<span class="t-dsc-small">(std::shared_ptr)</span></span><span>std::atomic_exchange<span class="t-dsc-small">(std::shared_ptr)</span></span><span>std::atomic_exchange_explicit<span class="t-dsc-small">(std::shared_ptr)</span></span><span>std::atomic_compare_exchange_weak<span class="t-dsc-small">(std::shared_ptr)</span></span><span>std::atomic_compare_exchange_strong<span class="t-dsc-small">(std::shared_ptr)</span></span><span>std::atomic_compare_exchange_weak_explicit<span class="t-dsc-small">(std::shared_ptr)</span></span><span>std::atomic_compare_exchange_strong_explicit<span class="t-dsc-small">(std::shared_ptr)</span></span></span></a></div></div>
</td>
<td> specializes atomic operations for <span class="t-lc"><a href="../../memory/shared_ptr.html" title="cpp/memory/shared ptr">std::shared_ptr</a></span> <br /> <span class="t-mark">(function template)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/memory/shared_ptr/dsc_atomic&action=edit">[edit]</a></span>
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