1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>basic_socket::async_wait</title> 5<link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../../boost_asio.html" title="Boost.Asio"> 8<link rel="up" href="../basic_socket.html" title="basic_socket"> 9<link rel="prev" href="async_connect.html" title="basic_socket::async_connect"> 10<link rel="next" href="at_mark.html" title="basic_socket::at_mark"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="async_connect.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../basic_socket.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../boost_asio.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="at_mark.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h4 class="title"> 27<a name="boost_asio.reference.basic_socket.async_wait"></a><a class="link" href="async_wait.html" title="basic_socket::async_wait">basic_socket::async_wait</a> 28</h4></div></div></div> 29<p> 30 <a class="indexterm" name="boost_asio.indexterm.basic_socket.async_wait"></a> 31Asynchronously 32 wait for the socket to become ready to read, ready to write, or to have 33 pending error conditions. 34 </p> 35<pre class="programlisting">template< 36 typename <a class="link" href="../WaitHandler.html" title="Wait handler requirements">WaitHandler</a> = <a class="link" href="../asynchronous_operations.html#boost_asio.reference.asynchronous_operations.default_completion_tokens"><span class="emphasis"><em>DEFAULT</em></span></a>> 37<a class="link" href="../asynchronous_operations.html#boost_asio.reference.asynchronous_operations.automatic_deduction_of_initiating_function_return_type"><span class="emphasis"><em>DEDUCED</em></span></a> async_wait( 38 wait_type w, 39 WaitHandler && handler = <a class="link" href="../asynchronous_operations.html#boost_asio.reference.asynchronous_operations.default_completion_tokens"><span class="emphasis"><em>DEFAULT</em></span></a>); 40</pre> 41<p> 42 This function is used to perform an asynchronous wait for a socket to enter 43 a ready to read, write or error condition state. 44 </p> 45<h6> 46<a name="boost_asio.reference.basic_socket.async_wait.h0"></a> 47 <span class="phrase"><a name="boost_asio.reference.basic_socket.async_wait.parameters"></a></span><a class="link" href="async_wait.html#boost_asio.reference.basic_socket.async_wait.parameters">Parameters</a> 48 </h6> 49<div class="variablelist"> 50<p class="title"><b></b></p> 51<dl class="variablelist"> 52<dt><span class="term">w</span></dt> 53<dd><p> 54 Specifies the desired socket state. 55 </p></dd> 56<dt><span class="term">handler</span></dt> 57<dd> 58<p> 59 The handler to be called when the wait operation completes. Copies 60 will be made of the handler as required. The function signature of 61 the handler must be: 62</p> 63<pre class="programlisting">void handler( 64 const boost::system::error_code& error // Result of operation 65); 66</pre> 67<p> 68 Regardless of whether the asynchronous operation completes immediately 69 or not, the handler will not be invoked from within this function. 70 On immediate completion, invocation of the handler will be performed 71 in a manner equivalent to using <a class="link" href="../post.html" title="post"><code class="computeroutput">post</code></a>. 72 </p> 73</dd> 74</dl> 75</div> 76<h6> 77<a name="boost_asio.reference.basic_socket.async_wait.h1"></a> 78 <span class="phrase"><a name="boost_asio.reference.basic_socket.async_wait.example"></a></span><a class="link" href="async_wait.html#boost_asio.reference.basic_socket.async_wait.example">Example</a> 79 </h6> 80<pre class="programlisting">void wait_handler(const boost::system::error_code& error) 81{ 82 if (!error) 83 { 84 // Wait succeeded. 85 } 86} 87 88... 89 90boost::asio::ip::tcp::socket socket(my_context); 91... 92socket.async_wait(boost::asio::ip::tcp::socket::wait_read, wait_handler); 93</pre> 94</div> 95<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 96<td align="left"></td> 97<td align="right"><div class="copyright-footer">Copyright © 2003-2020 Christopher M. 98 Kohlhoff<p> 99 Distributed under the Boost Software License, Version 1.0. (See accompanying 100 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>) 101 </p> 102</div></td> 103</tr></table> 104<hr> 105<div class="spirit-nav"> 106<a accesskey="p" href="async_connect.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../basic_socket.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../boost_asio.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="at_mark.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> 107</div> 108</body> 109</html> 110
