1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<head> 4<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 5<title>Global on_exit</title> 6<link rel="stylesheet" href="../../../../doc/src/boostbook.css" type="text/css"> 7<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 8<link rel="home" href="../../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> 9<link rel="up" href="../../process/reference.html#header.boost.process.async_hpp" title="Header <boost/process/async.hpp>"> 10<link rel="prev" href="argv.html" title="Global argv"> 11<link rel="next" href="async_pipe.html" title="Class async_pipe"> 12</head> 13<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 14<table cellpadding="2" width="100%"><tr> 15<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../boost.png"></td> 16<td align="center"><a 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class="refentrytitle">Global on_exit</span></h2> 30<p>boost::process::on_exit</p> 31</div> 32<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> 33<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: <<a class="link" href="../../process/reference.html#header.boost.process.async_hpp" title="Header <boost/process/async.hpp>">boost/process/async.hpp</a>> 34 35</span><span class="keyword">static</span> <span class="emphasis"><em><span class="identifier">unspecified</span></em></span> on_exit<span class="special">;</span></pre></div> 36<div class="refsect1"> 37<a name="id-1.3.30.9.3.5.4"></a><h2>Description</h2> 38<p>When an io_context is passed, the on_exit property can be used, to be notified when the child process exits.</p> 39<p>The following syntax is valid</p> 40<pre class="programlisting"><span class="identifier">on_exit</span><span class="special">=</span><span class="identifier">function</span><span class="special">;</span> 41<span class="identifier">on_exit</span><span class="special">(</span><span class="identifier">function</span><span class="special">)</span><span class="special">;</span> 42</pre> 43<p>with <code class="computeroutput">function</code> being a callable object with the signature <code class="computeroutput">(int, const std::error_code&)</code> or an <code class="computeroutput">std::future<int></code>.</p> 44<p><b>Example. </b></p> 45<p> 46</p> 47<pre class="programlisting"><span class="identifier">io_context</span> <span class="identifier">ios</span><span class="special">;</span> 48 49<span class="identifier">child</span> <span class="identifier">c</span><span class="special">(</span><span class="string">"ls"</span><span class="special">,</span> <span class="identifier">ios</span><span class="special">,</span> <span class="identifier">on_exit</span><span class="special">=</span><span class="special">[</span><span class="special">]</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">exit</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">error_code</span><span class="special">&</span> <span class="identifier">ec_in</span><span class="special">)</span><span class="special">{</span><span class="special">}</span><span class="special">)</span><span class="special">;</span> 50 51<span class="identifier">std</span><span class="special">::</span><span class="identifier">future</span><span class="special"><</span><span class="keyword">int</span><span class="special">></span> <span class="identifier">exit_code</span><span class="special">;</span> 52<span class="identifier">chlid</span> <span class="identifier">c2</span><span class="special">(</span><span class="string">"ls"</span><span class="special">,</span> <span class="identifier">ios</span><span class="special">,</span> <span class="identifier">on_exit</span><span class="special">=</span><span class="identifier">exit_code</span><span class="special">)</span><span class="special">;</span> 53</pre> 54<div class="note"><table border="0" summary="Note"> 55<tr> 56<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../doc/src/images/note.png"></td> 57<th align="left">Note</th> 58</tr> 59<tr><td align="left" valign="top"><p>The handler is not invoked when the launch fails. </p></td></tr> 60</table></div> 61<p> 62</p> 63<div class="warning"><table border="0" summary="Warning"> 64<tr> 65<td rowspan="2" align="center" valign="top" width="25"><img alt="[Warning]" src="../../../../doc/src/images/warning.png"></td> 66<th align="left">Warning</th> 67</tr> 68<tr><td align="left" valign="top"><p>When used ignore_error it might get invoked on error. </p></td></tr> 69</table></div> 70<p> 71</p> 72<div class="warning"><table border="0" summary="Warning"> 73<tr> 74<td rowspan="2" align="center" valign="top" width="25"><img alt="[Warning]" src="../../../../doc/src/images/warning.png"></td> 75<th align="left">Warning</th> 76</tr> 77<tr><td align="left" valign="top"><p><code class="computeroutput">on_exit</code> uses <code class="computeroutput">boost::asio::signal_set</code> to listen for <code class="computeroutput">SIGCHLD</code> on posix, and so has the same restrictions as that class (do not register a handler for <code class="computeroutput">SIGCHLD</code> except by using <code class="computeroutput">boost::asio::signal_set</code>). </p></td></tr> 78</table></div> 79<p> 80</p> 81</div> 82</div> 83<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 84<td align="left"></td> 85<td align="right"><div class="copyright-footer">Copyright © 2006-2012 Julio M. Merino Vidal, Ilya Sokolov, 86 Felipe Tanus, Jeff Flinn, Boris Schaeling<br>Copyright © 2016 Klemens D. Morgenstern<p> 87 Distributed under the Boost Software License, Version 1.0. (See accompanying 88 file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 89 </p> 90</div></td> 91</tr></table> 92<hr> 93<div class="spirit-nav"> 94<a accesskey="p" href="argv.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../process/reference.html#header.boost.process.async_hpp"><img src="../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="async_pipe.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> 95</div> 96</body> 97</html> 98
