1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Legacy 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="IteratorConnectHandler.html" title="Iterator connect handler requirements"> 10<link rel="next" href="MoveAcceptHandler.html" title="Move accept handler 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="IteratorConnectHandler.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="MoveAcceptHandler.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.LegacyCompletionHandler"></a><a class="link" href="LegacyCompletionHandler.html" title="Legacy completion handler requirements">Legacy 28 completion handler requirements</a> 29</h3></div></div></div> 30<p> 31 A legacy completion handler must meet the requirements for a <a class="link" href="Handler.html" title="Handlers">handler</a>. 32 A legacy completion handler must meet the requirements of <code class="computeroutput">CopyConstructible</code> 33 types (C++Std [copyconstructible]). A value <code class="computeroutput">h</code> of a completion 34 handler class should work correctly in the expression <code class="computeroutput">h()</code>. 35 </p> 36<h5> 37<a name="boost_asio.reference.LegacyCompletionHandler.h0"></a> 38 <span class="phrase"><a name="boost_asio.reference.LegacyCompletionHandler.examples"></a></span><a class="link" href="LegacyCompletionHandler.html#boost_asio.reference.LegacyCompletionHandler.examples">Examples</a> 39 </h5> 40<p> 41 A free function as a completion handler: 42 </p> 43<pre class="programlisting">void completion_handler() 44{ 45 ... 46} 47</pre> 48<p> 49 A completion handler function object: 50 </p> 51<pre class="programlisting">struct completion_handler 52{ 53 ... 54 void operator()() 55 { 56 ... 57 } 58 ... 59}; 60</pre> 61<p> 62 A lambda as a completion handler: 63 </p> 64<pre class="programlisting">my_io_service.post( 65 []() 66 { 67 ... 68 }); 69</pre> 70<p> 71 A non-static class member function adapted to a completion handler using 72 <code class="computeroutput">std::bind()</code>: 73 </p> 74<pre class="programlisting">void my_class::completion_handler() 75{ 76 ... 77} 78... 79my_io_service.post(std::bind(&my_class::completion_handler, this)); 80</pre> 81<p> 82 A non-static class member function adapted to a completion handler using 83 <code class="computeroutput">boost::bind()</code>: 84 </p> 85<pre class="programlisting">void my_class::completion_handler() 86{ 87 ... 88} 89... 90my_io_service.post(boost::bind(&my_class::completion_handler, this)); 91</pre> 92</div> 93<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 94<td align="left"></td> 95<td align="right"><div class="copyright-footer">Copyright © 2003-2020 Christopher M. 96 Kohlhoff<p> 97 Distributed under the Boost Software License, Version 1.0. (See accompanying 98 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>) 99 </p> 100</div></td> 101</tr></table> 102<hr> 103<div class="spirit-nav"> 104<a accesskey="p" href="IteratorConnectHandler.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="MoveAcceptHandler.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> 105</div> 106</body> 107</html> 108
