async_wait.html
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<div class="titlepage"><div><div><h4 class="title">
<a name="asio.reference.basic_socket.async_wait"></a><a class="link" href="async_wait.html" title="basic_socket::async_wait">basic_socket::async_wait</a>
</h4></div></div></div>
<p>
<a class="indexterm" name="asio.indexterm.basic_socket.async_wait"></a>
Asynchronously
wait for the socket to become ready to read, ready to write, or to have
pending error conditions.
</p>
<pre class="programlisting">template<
typename <a class="link" href="../WaitHandler.html" title="Wait handler requirements">WaitHandler</a> = <a class="link" href="../asynchronous_operations.html#asio.reference.asynchronous_operations.default_completion_tokens"><span class="emphasis"><em>DEFAULT</em></span></a>>
<a class="link" href="../asynchronous_operations.html#asio.reference.asynchronous_operations.automatic_deduction_of_initiating_function_return_type"><span class="emphasis"><em>DEDUCED</em></span></a> async_wait(
wait_type w,
WaitHandler && handler = <a class="link" href="../asynchronous_operations.html#asio.reference.asynchronous_operations.default_completion_tokens"><span class="emphasis"><em>DEFAULT</em></span></a>);
</pre>
<p>
This function is used to perform an asynchronous wait for a socket to enter
a ready to read, write or error condition state.
</p>
<h6>
<a name="asio.reference.basic_socket.async_wait.h0"></a>
<span><a name="asio.reference.basic_socket.async_wait.parameters"></a></span><a class="link" href="async_wait.html#asio.reference.basic_socket.async_wait.parameters">Parameters</a>
</h6>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">w</span></dt>
<dd><p>
Specifies the desired socket state.
</p></dd>
<dt><span class="term">handler</span></dt>
<dd>
<p>
The handler to be called when the wait operation completes. Copies
will be made of the handler as required. The function signature of
the handler must be:
</p>
<pre class="programlisting">void handler(
const asio::error_code& error // Result of operation
);
</pre>
<p>
Regardless of whether the asynchronous operation completes immediately
or not, the handler will not be invoked from within this function.
On immediate completion, invocation of the handler will be performed
in a manner equivalent to using <a class="link" href="../post.html" title="post"><code class="computeroutput">post</code></a>.
</p>
</dd>
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<h6>
<a name="asio.reference.basic_socket.async_wait.h1"></a>
<span><a name="asio.reference.basic_socket.async_wait.example"></a></span><a class="link" href="async_wait.html#asio.reference.basic_socket.async_wait.example">Example</a>
</h6>
<pre class="programlisting">void wait_handler(const asio::error_code& error)
{
if (!error)
{
// Wait succeeded.
}
}
...
asio::ip::tcp::socket socket(my_context);
...
socket.async_wait(asio::ip::tcp::socket::wait_read, wait_handler);
</pre>
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<td align="right"><div class="copyright-footer">Copyright © 2003-2020 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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