1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Reactor-Style Operations</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="../core.html" title="Core Concepts and Functionality"> 9<link rel="prev" href="streams.html" title="Streams, Short Reads and Short Writes"> 10<link rel="next" href="line_based.html" title="Line-Based Operations"> 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="streams.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../core.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="line_based.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.overview.core.reactor"></a><a class="link" href="reactor.html" title="Reactor-Style Operations">Reactor-Style Operations</a> 28</h4></div></div></div> 29<p> 30 Sometimes a program must be integrated with a third-party library that 31 wants to perform the I/O operations itself. To facilitate this, Boost.Asio 32 includes synchronous and asynchronous operations that may be used to wait 33 for a socket to become ready to read, ready to write, or to have a pending 34 error condition. 35 </p> 36<p> 37 As an example, to perform a non-blocking read something like the following 38 may be used: 39 </p> 40<pre class="programlisting"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">socket</span> <span class="identifier">socket</span><span class="special">(</span><span class="identifier">my_io_context</span><span class="special">);</span> 41<span class="special">...</span> 42<span class="identifier">socket</span><span class="special">.</span><span class="identifier">non_blocking</span><span class="special">(</span><span class="keyword">true</span><span class="special">);</span> 43<span class="special">...</span> 44<span class="identifier">socket</span><span class="special">.</span><span class="identifier">async_wait</span><span class="special">(</span><span class="identifier">ip</span><span class="special">::</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">socket</span><span class="special">::</span><span class="identifier">wait_read</span><span class="special">,</span> <span class="identifier">read_handler</span><span class="special">);</span> 45<span class="special">...</span> 46<span class="keyword">void</span> <span class="identifier">read_handler</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system</span><span class="special">::</span><span class="identifier">error_code</span> <span class="identifier">ec</span><span class="special">)</span> 47<span class="special">{</span> 48 <span class="keyword">if</span> <span class="special">(!</span><span class="identifier">ec</span><span class="special">)</span> 49 <span class="special">{</span> 50 <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="keyword">char</span><span class="special">></span> <span class="identifier">buf</span><span class="special">(</span><span class="identifier">socket</span><span class="special">.</span><span class="identifier">available</span><span class="special">());</span> 51 <span class="identifier">socket</span><span class="special">.</span><span class="identifier">read_some</span><span class="special">(</span><span class="identifier">buffer</span><span class="special">(</span><span class="identifier">buf</span><span class="special">));</span> 52 <span class="special">}</span> 53<span class="special">}</span> 54</pre> 55<p> 56 These operations are supported for sockets on all platforms, and for the 57 POSIX stream-oriented descriptor classes. 58 </p> 59<h6> 60<a name="boost_asio.overview.core.reactor.h0"></a> 61 <span class="phrase"><a name="boost_asio.overview.core.reactor.see_also"></a></span><a class="link" href="reactor.html#boost_asio.overview.core.reactor.see_also">See 62 Also</a> 63 </h6> 64<p> 65 <a class="link" href="../../reference/basic_socket/wait.html" title="basic_socket::wait">basic_socket::wait()</a>, 66 <a class="link" href="../../reference/basic_socket/async_wait.html" title="basic_socket::async_wait">basic_socket::async_wait()</a>, 67 <a class="link" href="../../reference/basic_socket/non_blocking.html" title="basic_socket::non_blocking">basic_socket::non_blocking()</a>, 68 <a class="link" href="../../reference/basic_socket/native_non_blocking.html" title="basic_socket::native_non_blocking">basic_socket::native_non_blocking()</a>, 69 <a class="link" href="../../examples/cpp03_examples.html#boost_asio.examples.cpp03_examples.nonblocking">nonblocking 70 example</a>. 71 </p> 72</div> 73<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 74<td align="left"></td> 75<td align="right"><div class="copyright-footer">Copyright © 2003-2020 Christopher M. 76 Kohlhoff<p> 77 Distributed under the Boost Software License, Version 1.0. (See accompanying 78 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>) 79 </p> 80</div></td> 81</tr></table> 82<hr> 83<div class="spirit-nav"> 84<a accesskey="p" href="streams.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../core.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="line_based.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> 85</div> 86</body> 87</html> 88
