Insane_DNS/libraries/asio-1.28.1/doc/asio/reference/OperationState.html

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<a name="asio.reference.OperationState"></a><a class="link" href="OperationState.html" title="Operation state concept">Operation state concept</a>
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<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">O</span><span class="special">&gt;</span>
<span class="identifier">concept</span> <span class="identifier">operation_state</span> <span class="special">=</span>
<span class="identifier">destructible</span><span class="special">&lt;</span><span class="identifier">O</span><span class="special">&gt;</span> <span class="special">&amp;&amp;</span>
<span class="identifier">is_object_v</span><span class="special">&lt;</span><span class="identifier">O</span><span class="special">&gt;</span> <span class="special">&amp;&amp;</span>
<span class="identifier">requires</span> <span class="special">(</span><span class="identifier">O</span><span class="special">&amp;</span> <span class="identifier">o</span><span class="special">)</span> <span class="special">{</span>
<span class="special">{</span> <span class="identifier">execution</span><span class="special">::</span><span class="identifier">start</span><span class="special">(</span><span class="identifier">o</span><span class="special">)</span> <span class="special">}</span> <span class="keyword">noexcept</span><span class="special">;</span>
<span class="special">};</span>
</pre>
<p>
An object whose type satisfies <code class="computeroutput"><span class="identifier">operation_state</span></code>
represents the state of an asynchronous operation. It is the result of calling
<code class="computeroutput"><span class="identifier">execution</span><span class="special">::</span><span class="identifier">connect</span></code> with a <code class="computeroutput"><span class="identifier">sender</span></code>
and a <code class="computeroutput"><span class="identifier">receiver</span></code>.
</p>
<p>
<code class="computeroutput"><span class="identifier">execution</span><span class="special">::</span><span class="identifier">start</span></code> may be called on an <code class="computeroutput"><span class="identifier">operation_state</span></code> object at most once. Once
<code class="computeroutput"><span class="identifier">execution</span><span class="special">::</span><span class="identifier">start</span></code> has been invoked, the caller shall
ensure that the start of a non-exceptional invocation of one of the receiver's
completion-signalling operations strongly happens before [intro.multithread]
the call to the <code class="computeroutput"><span class="identifier">operation_state</span></code>
destructor.
</p>
<p>
The start of the invocation of <code class="computeroutput"><span class="identifier">execution</span><span class="special">::</span><span class="identifier">start</span></code>
shall strongly happen before [intro.multithread] the invocation of one of
the three receiver operations.
</p>
<p>
<code class="computeroutput"><span class="identifier">execution</span><span class="special">::</span><span class="identifier">start</span></code> may or may not block pending the
successful transfer of execution to one of the three receiver operations.
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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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