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<div class="titlepage"><div><div><h3 class="title">
<a name="asio.reference.execution__start"></a><a class="link" href="execution__start.html" title="execution::start">execution::start</a>
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<p>
<a class="indexterm" name="asio.indexterm.execution__start"></a>
</p>
<p>
A customisation point that notifies an operation state object to start its
associated operation.
</p>
<pre class="programlisting"><span class="keyword">constexpr</span> <span class="identifier">unspecified</span> <span class="identifier">start</span> <span class="special">=</span> <span class="identifier">unspecified</span><span class="special">;</span>
</pre>
<p>
The name <code class="computeroutput"><span class="identifier">execution</span><span class="special">::</span><span class="identifier">start</span></code> denotes a customisation point object.
The expression <code class="computeroutput"><span class="identifier">execution</span><span class="special">::</span><span class="identifier">start</span><span class="special">(</span><span class="identifier">R</span><span class="special">)</span></code>
for some subexpression <code class="computeroutput"><span class="identifier">R</span></code>
is expression-equivalent to:
</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
<code class="computeroutput"><span class="identifier">R</span><span class="special">.</span><span class="identifier">start</span><span class="special">()</span></code>,
if that expression is valid.
</li>
<li class="listitem">
Otherwise, <code class="computeroutput"><span class="identifier">start</span><span class="special">(</span><span class="identifier">R</span><span class="special">)</span></code>,
if that expression is valid, with overload resolution performed in a
context that includes the declaration <code class="computeroutput"><span class="keyword">void</span>
<span class="identifier">start</span><span class="special">();</span></code>
and that does not include a declaration of <code class="computeroutput"><span class="identifier">execution</span><span class="special">::</span><span class="identifier">start</span></code>.
</li>
<li class="listitem">
Otherwise, <code class="computeroutput"><span class="identifier">execution</span><span class="special">::</span><span class="identifier">start</span><span class="special">(</span><span class="identifier">R</span><span class="special">)</span></code> is ill-formed.
</li>
</ul></div>
<h5>
<a name="asio.reference.execution__start.h0"></a>
<span><a name="asio.reference.execution__start.requirements"></a></span><a class="link" href="execution__start.html#asio.reference.execution__start.requirements">Requirements</a>
</h5>
<p>
<span class="emphasis"><em>Header: </em></span><code class="literal">asio/execution/start.hpp</code>
</p>
<p>
<span class="emphasis"><em>Convenience header: </em></span><code class="literal">asio/execution.hpp</code>
</p>
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<div class="copyright-footer">Copyright © 2003-2023 Christopher M. Kohlhoff<p>
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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