1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Class template callback</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="../../../index.html" title="Chapter 1. Boost.Log v2"> 8<link rel="up" href="../type_dispatcher.html#idm44984847500928" title="Description"> 9<link rel="prev" href="../type_dispatcher.html" title="Class type_dispatcher"> 10<link rel="next" href="../../../BOOST_LO_idm46079572479456.html" title="Macro BOOST_LOG_UNIQUE_IDENTIFIER_NAME"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr><td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../boost.png"></td></tr></table> 14<hr> 15<div class="spirit-nav"> 16<a accesskey="p" href="../type_dispatcher.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../type_dispatcher.html#idm44984847500928"><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="../../../BOOST_LO_idm46079572479456.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 17</div> 18<div class="refentry"> 19<a name="boost.log.type_dispatcher.callback"></a><div class="titlepage"></div> 20<div class="refnamediv"> 21<h2><span class="refentrytitle">Class template callback</span></h2> 22<p>boost::log::type_dispatcher::callback</p> 23</div> 24<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> 25<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="../../../utilities.html#header.boost.log.utility.type_dispatch.type_dispatcher_hpp" title="Header <boost/log/utility/type_dispatch/type_dispatcher.hpp>">boost/log/utility/type_dispatch/type_dispatcher.hpp</a>> 26 27</span> 28<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> 29<span class="keyword">class</span> <a class="link" href="callback.html" title="Class template callback">callback</a> <span class="special">{</span> 30<span class="keyword">public</span><span class="special">:</span> 31 32 <span class="comment">// <a class="link" href="callback.html#idm46079572496768-bb">public member functions</a></span> 33 <span class="keyword">void</span> <a class="link" href="callback.html#idm46079572496208-bb"><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span></a><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span> <span class="special">&</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 34 <span class="keyword">explicit</span> <a class="link" href="callback.html#idm46079572493232-bb"><span class="keyword">operator</span> <span class="keyword">bool</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span> 35 <span class="keyword">bool</span> <a class="link" href="callback.html#idm46079572491376-bb"><span class="keyword">operator</span><span class="special">!</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span> 36<span class="special">}</span><span class="special">;</span></pre></div> 37<div class="refsect1"> 38<a name="idm44984847442832"></a><h2>Description</h2> 39<p>This interface is used by type dispatchers to consume the dispatched value. </p> 40<div class="refsect2"> 41<a name="idm44984847442064"></a><h3> 42<a name="idm46079572496768-bb"></a><code class="computeroutput">callback</code> public member functions</h3> 43<div class="orderedlist"><ol class="orderedlist" type="1"> 44<li class="listitem"> 45<pre class="literallayout"><span class="keyword">void</span> <a name="idm46079572496208-bb"></a><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span> <span class="special">&</span> value<span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre> 46<p>The operator invokes the visitor-specific logic with the given value</p> 47<p> 48</p> 49<div class="variablelist"><table border="0" class="variablelist compact"> 50<colgroup> 51<col align="left" valign="top"> 52<col> 53</colgroup> 54<tbody><tr> 55<td><p><span class="term">Parameters:</span></p></td> 56<td><div class="variablelist"><table border="0" class="variablelist compact"> 57<colgroup> 58<col align="left" valign="top"> 59<col> 60</colgroup> 61<tbody><tr> 62<td><p><span class="term"><code class="computeroutput">value</code></span></p></td> 63<td><p>The dispatched value </p></td> 64</tr></tbody> 65</table></div></td> 66</tr></tbody> 67</table></div> 68</li> 69<li class="listitem"> 70<pre class="literallayout"><span class="keyword">explicit</span> <a name="idm46079572493232-bb"></a><span class="keyword">operator</span> <span class="keyword">bool</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span></pre> 71<p>The operator checks if the visitor is attached to a receiver </p> 72</li> 73<li class="listitem"> 74<pre class="literallayout"><span class="keyword">bool</span> <a name="idm46079572491376-bb"></a><span class="keyword">operator</span><span class="special">!</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span></pre> 75<p>The operator checks if the visitor is not attached to a receiver </p> 76</li> 77</ol></div> 78</div> 79</div> 80</div> 81<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 82<td align="left"></td> 83<td align="right"><div class="copyright-footer">Copyright © 2007-2019 Andrey Semashev<p> 84 Distributed under the Boost Software License, Version 1.0. (See accompanying 85 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>). 86 </p> 87</div></td> 88</tr></table> 89<hr> 90<div class="spirit-nav"> 91<a accesskey="p" href="../type_dispatcher.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../type_dispatcher.html#idm44984847500928"><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="../../../BOOST_LO_idm46079572479456.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 92</div> 93</body> 94</html> 95
