1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Completion handler requirements</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="../reference.html" title="Reference"> 9<link rel="prev" href="CompletionCondition.html" title="Completion condition requirements"> 10<link rel="next" href="ConnectCondition.html" title="Connect condition requirements"> 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="CompletionCondition.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../reference.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="ConnectCondition.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h3 class="title"> 27<a name="boost_asio.reference.CompletionHandler"></a><a class="link" href="CompletionHandler.html" title="Completion handler requirements">Completion handler 28 requirements</a> 29</h3></div></div></div> 30<p> 31 A completion handler must meet the requirements for a <a class="link" href="Handler.html" title="Handlers">handler</a>. 32 A value <code class="computeroutput">h</code> of a completion handler class should work correctly 33 in the expression <code class="computeroutput">h()</code>. 34 </p> 35<h5> 36<a name="boost_asio.reference.CompletionHandler.h0"></a> 37 <span class="phrase"><a name="boost_asio.reference.CompletionHandler.examples"></a></span><a class="link" href="CompletionHandler.html#boost_asio.reference.CompletionHandler.examples">Examples</a> 38 </h5> 39<p> 40 A free function as a completion handler: 41 </p> 42<pre class="programlisting">void completion_handler() 43{ 44 ... 45} 46</pre> 47<p> 48 A completion handler function object: 49 </p> 50<pre class="programlisting">struct completion_handler 51{ 52 ... 53 void operator()() 54 { 55 ... 56 } 57 ... 58}; 59</pre> 60<p> 61 A lambda as a completion handler: 62 </p> 63<pre class="programlisting">my_io_service.post( 64 []() 65 { 66 ... 67 }); 68</pre> 69<p> 70 A non-static class member function adapted to a completion handler using 71 <code class="computeroutput">std::bind()</code>: 72 </p> 73<pre class="programlisting">void my_class::completion_handler() 74{ 75 ... 76} 77... 78my_io_service.post(std::bind(&my_class::completion_handler, this)); 79</pre> 80<p> 81 A non-static class member function adapted to a completion handler using 82 <code class="computeroutput">boost::bind()</code>: 83 </p> 84<pre class="programlisting">void my_class::completion_handler() 85{ 86 ... 87} 88... 89my_io_service.post(boost::bind(&my_class::completion_handler, this)); 90</pre> 91</div> 92<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 93<td align="left"></td> 94<td align="right"><div class="copyright-footer">Copyright © 2003-2020 Christopher M. 95 Kohlhoff<p> 96 Distributed under the Boost Software License, Version 1.0. (See accompanying 97 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>) 98 </p> 99</div></td> 100</tr></table> 101<hr> 102<div class="spirit-nav"> 103<a accesskey="p" href="CompletionCondition.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../reference.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="ConnectCondition.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> 104</div> 105</body> 106</html> 107
