<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> <title>Completion handler requirements</title> <link rel="stylesheet" href="../../boostbook.css" type="text/css"> <meta name="generator" content="DocBook XSL Stylesheets V1.75.2"> <link rel="home" href="../../boost_asio.html" title="Boost.Asio"> <link rel="up" href="../reference.html" title="Reference"> <link rel="prev" href="AsyncWriteStream.html" title="Buffer-oriented asynchronous write stream requirements"> <link rel="next" href="ConnectHandler.html" title="Connect handler requirements"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> <table cellpadding="2" width="100%"><tr> <td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../boost.png"></td> <td align="center"><a href="../../../../index.html">Home</a></td> <td align="center"><a href="../../../../libs/libraries.htm">Libraries</a></td> <td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> <td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> <td align="center"><a href="../../../../more/index.htm">More</a></td> </tr></table> <hr> <div class="spirit-nav"> <a accesskey="p" href="AsyncWriteStream.html"><img src="../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../reference.html"><img src="../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../../boost_asio.html"><img src="../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="ConnectHandler.html"><img src="../../../../doc/html/images/next.png" alt="Next"></a> </div> <div class="section" title="Completion handler requirements"> <div class="titlepage"><div><div><h3 class="title"> <a name="boost_asio.reference.CompletionHandler"></a><a class="link" href="CompletionHandler.html" title="Completion handler requirements"> Completion handler requirements</a> </h3></div></div></div> <p> A completion handler must meet the requirements for a <a class="link" href="Handler.html" title="Handlers">handler</a>. A value <code class="computeroutput"><span class="identifier">h</span></code> of a completion handler class should work correctly in the expression <code class="computeroutput"><span class="identifier">h</span><span class="special">()</span></code>. </p> <a name="boost_asio.reference.CompletionHandler.examples"></a><h5> <a name="id616464"></a> <a class="link" href="CompletionHandler.html#boost_asio.reference.CompletionHandler.examples">Examples</a> </h5> <p> A free function as a completion handler: </p> <pre class="programlisting"><span class="keyword">void</span> <span class="identifier">completion_handler</span><span class="special">()</span> <span class="special">{</span> <span class="special">...</span> <span class="special">}</span> </pre> <p> A completion handler function object: </p> <pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">completion_handler</span> <span class="special">{</span> <span class="special">...</span> <span class="keyword">void</span> <span class="keyword">operator</span><span class="special">()()</span> <span class="special">{</span> <span class="special">...</span> <span class="special">}</span> <span class="special">...</span> <span class="special">};</span> </pre> <p> A non-static class member function adapted to a completion handler using <code class="computeroutput"><span class="identifier">bind</span><span class="special">()</span></code>: </p> <pre class="programlisting"><span class="keyword">void</span> <span class="identifier">my_class</span><span class="special">::</span><span class="identifier">completion_handler</span><span class="special">()</span> <span class="special">{</span> <span class="special">...</span> <span class="special">}</span> <span class="special">...</span> <span class="identifier">my_io_service</span><span class="special">.</span><span class="identifier">post</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">bind</span><span class="special">(&</span><span class="identifier">my_class</span><span class="special">::</span><span class="identifier">completion_handler</span><span class="special">,</span> <span class="keyword">this</span><span class="special">));</span> </pre> </div> <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> <td align="left"></td> <td align="right"><div class="copyright-footer">Copyright © 2003 - 2010 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>) </p> </div></td> </tr></table> <hr> <div class="spirit-nav"> <a accesskey="p" href="AsyncWriteStream.html"><img src="../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../reference.html"><img src="../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../../boost_asio.html"><img src="../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="ConnectHandler.html"><img src="../../../../doc/html/images/next.png" alt="Next"></a> </div> </body> </html>