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<div class="titlepage"><div><div><h3 class="title">
<a name="asio.reference.use_awaitable_t"></a><a class="link" href="use_awaitable_t.html" title="use_awaitable_t">use_awaitable_t</a>
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<p>
<a class="indexterm" name="asio.indexterm.use_awaitable_t"></a>
</p>
<p>
A <a class="link" href="../overview/model/completion_tokens.html" title="Completion Tokens">completion token</a>
that represents the currently executing coroutine.
</p>
<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span>
<span class="keyword">typename</span> <a class="link" href="Executor1.html" title="Executor requirements">Executor</a> <span class="special">=</span> <span class="identifier">any_io_executor</span><span class="special">></span>
<span class="keyword">struct</span> <span class="identifier">use_awaitable_t</span>
</pre>
<h5>
<a name="asio.reference.use_awaitable_t.h0"></a>
<span><a name="asio.reference.use_awaitable_t.types"></a></span><a class="link" href="use_awaitable_t.html#asio.reference.use_awaitable_t.types">Types</a>
</h5>
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<colgroup>
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Name
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Description
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<td>
<p>
<a class="link" href="use_awaitable_t__executor_with_default.html" title="use_awaitable_t::executor_with_default"><span class="bold"><strong>executor_with_default</strong></span></a>
</p>
</td>
<td>
<p>
Adapts an executor to add the use_awaitable_t completion token
as the default.
</p>
</td>
</tr></tbody>
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<h5>
<a name="asio.reference.use_awaitable_t.h1"></a>
<span><a name="asio.reference.use_awaitable_t.member_functions"></a></span><a class="link" href="use_awaitable_t.html#asio.reference.use_awaitable_t.member_functions">Member
Functions</a>
</h5>
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Name
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Description
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<td>
<p>
<a class="link" href="use_awaitable_t/as_default_on.html" title="use_awaitable_t::as_default_on"><span class="bold"><strong>as_default_on</strong></span></a> <span class="silver">[static]</span>
</p>
</td>
<td>
<p>
Function helper to adapt an I/O object to use use_awaitable_t as
its default completion token type.
</p>
</td>
</tr>
<tr>
<td>
<p>
<a class="link" href="use_awaitable_t/use_awaitable_t.html" title="use_awaitable_t::use_awaitable_t"><span class="bold"><strong>use_awaitable_t</strong></span></a> <span class="silver">[constructor]</span>
</p>
</td>
<td>
<p>
Default constructor. <br> <span class="silver"> —</span><br> Constructor used to specify
file name, line, and function name.
</p>
</td>
</tr>
</tbody>
</table></div>
<p>
The <code class="computeroutput"><span class="identifier">use_awaitable_t</span></code> class,
with its value <code class="computeroutput"><span class="identifier">use_awaitable</span></code>,
is used to represent the currently executing coroutine. This completion token
may be passed as a handler to an asynchronous operation. For example:
</p>
<pre class="programlisting"><span class="identifier">awaitable</span><span class="special"><</span><span class="keyword">void</span><span class="special">></span> <span class="identifier">my_coroutine</span><span class="special">()</span>
<span class="special">{</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">n</span> <span class="special">=</span> <span class="identifier">co_await</span> <span class="identifier">my_socket</span><span class="special">.</span><span class="identifier">async_read_some</span><span class="special">(</span><span class="identifier">buffer</span><span class="special">,</span> <span class="identifier">use_awaitable</span><span class="special">);</span>
<span class="special">...</span>
<span class="special">}</span>
</pre>
<p>
When used with co_await, the initiating function (<code class="computeroutput"><span class="identifier">async_read_some</span></code>
in the above example) suspends the current coroutine. The coroutine is resumed
when the asynchronous operation completes, and the result of the operation
is returned.
</p>
<h5>
<a name="asio.reference.use_awaitable_t.h2"></a>
<span><a name="asio.reference.use_awaitable_t.requirements"></a></span><a class="link" href="use_awaitable_t.html#asio.reference.use_awaitable_t.requirements">Requirements</a>
</h5>
<p>
<span class="emphasis"><em>Header: </em></span><code class="literal">asio/use_awaitable.hpp</code>
</p>
<p>
<span class="emphasis"><em>Convenience header: </em></span><code class="literal">asio.hpp</code>
</p>
</div>
<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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