doc/html/boost_asio/reference/SignalHandler.html

   1 <html>
   2 <head>
   3 <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
   4 <title>Signal handler requirements</title>
   5 <link rel="stylesheet" href="../../../../doc/src/boostbook.css" type="text/css">
   6 <meta name="generator" content="DocBook XSL Stylesheets V1.78.1">
   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="ShutdownHandler.html" title="SSL shutdown handler requirements">
  10 <link rel="next" href="SignalSetService.html" title="Signal set service 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="ShutdownHandler.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="SignalSetService.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.SignalHandler"></a><a class="link" href="SignalHandler.html" title="Signal handler requirements">Signal handler requirements</a>
  28 </h3></div></div></div>
  29 <p>
  30         A signal handler must meet the requirements for a <a class="link" href="Handler.html" title="Handlers">handler</a>.
  31         A value <code class="computeroutput"><span class="identifier">h</span></code> of a signal handler
  32         class should work correctly in the expression <code class="computeroutput"><span class="identifier">h</span><span class="special">(</span><span class="identifier">ec</span><span class="special">,</span>
  33         <span class="identifier">n</span><span class="special">)</span></code>,
  34         where <code class="computeroutput"><span class="identifier">ec</span></code> is an lvalue of
  35         type <code class="computeroutput"><span class="keyword">const</span> <span class="identifier">error_code</span></code>
  36         and <code class="computeroutput"><span class="identifier">n</span></code> is an lvalue of type
  37         <code class="computeroutput"><span class="keyword">const</span> <span class="keyword">int</span></code>.
  38       </p>
  39 <h5>
  40 <a name="boost_asio.reference.SignalHandler.h0"></a>
  41         <span class="phrase"><a name="boost_asio.reference.SignalHandler.examples"></a></span><a class="link" href="SignalHandler.html#boost_asio.reference.SignalHandler.examples">Examples</a>
  42       </h5>
  43 <p>
  44         A free function as a signal handler:
  45       </p>
  46 <pre class="programlisting"><span class="keyword">void</span> <span class="identifier">signal_handler</span><span class="special">(</span>
  47     <span class="keyword">const</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="special">&amp;</span> <span class="identifier">ec</span><span class="special">,</span>
  48     <span class="keyword">int</span> <span class="identifier">signal_number</span><span class="special">)</span>
  49 <span class="special">{</span>
  50   <span class="special">...</span>
  51 <span class="special">}</span>
  52 </pre>
  53 <p>
  54         A signal handler function object:
  55       </p>
  56 <pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">signal_handler</span>
  57 <span class="special">{</span>
  58   <span class="special">...</span>
  59   <span class="keyword">void</span> <span class="keyword">operator</span><span class="special">()(</span>
  60       <span class="keyword">const</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="special">&amp;</span> <span class="identifier">ec</span><span class="special">,</span>
  61       <span class="keyword">int</span> <span class="identifier">signal_number</span><span class="special">)</span>
  62   <span class="special">{</span>
  63     <span class="special">...</span>
  64   <span class="special">}</span>
  65   <span class="special">...</span>
  66 <span class="special">};</span>
  67 </pre>
  68 <p>
  69         A non-static class member function adapted to a signal handler using <code class="computeroutput"><span class="identifier">bind</span><span class="special">()</span></code>:
  70       </p>
  71 <pre class="programlisting"><span class="keyword">void</span> <span class="identifier">my_class</span><span class="special">::</span><span class="identifier">signal_handler</span><span class="special">(</span>
  72     <span class="keyword">const</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="special">&amp;</span> <span class="identifier">ec</span><span class="special">,</span>
  73     <span class="keyword">int</span> <span class="identifier">signal_number</span><span class="special">)</span>
  74 <span class="special">{</span>
  75   <span class="special">...</span>
  76 <span class="special">}</span>
  77 <span class="special">...</span>
  78 <span class="identifier">my_signal_set</span><span class="special">.</span><span class="identifier">async_wait</span><span class="special">(</span>
  79     <span class="identifier">boost</span><span class="special">::</span><span class="identifier">bind</span><span class="special">(&amp;</span><span class="identifier">my_class</span><span class="special">::</span><span class="identifier">signal_handler</span><span class="special">,</span>
  80       <span class="keyword">this</span><span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">placeholders</span><span class="special">::</span><span class="identifier">error</span><span class="special">,</span>
  81       <span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">placeholders</span><span class="special">::</span><span class="identifier">signal_number</span><span class="special">));</span>
  82 </pre>
  83 </div>
  84 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
  85 <td align="left"></td>
  86 <td align="right"><div class="copyright-footer">Copyright &#169; 2003-2014 Christopher M. Kohlhoff<p>
  87         Distributed under the Boost Software License, Version 1.0. (See accompanying
  88         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>)
  89       </p>
  90 </div></td>
  91 </tr></table>
  92 <hr>
  93 <div class="spirit-nav">
  94 <a accesskey="p" href="ShutdownHandler.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="SignalSetService.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a>
  95 </div>
  96 </body>
  97 </html>