1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Class template attribute_actor</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="../../../expressions.html#header.boost.log.expressions.attr_fwd_hpp" title="Header <boost/log/expressions/attr_fwd.hpp>"> 9<link rel="prev" href="attr_idm46079581363536.html" title="Function template attr"> 10<link rel="next" href="attribute_terminal.html" title="Class template attribute_terminal"> 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="attr_idm46079581363536.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../../expressions.html#header.boost.log.expressions.attr_fwd_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="attribute_terminal.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 17</div> 18<div class="refentry"> 19<a name="boost.log.expressions.attribute_actor"></a><div class="titlepage"></div> 20<div class="refnamediv"> 21<h2><span class="refentrytitle">Class template attribute_actor</span></h2> 22<p>boost::log::expressions::attribute_actor</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="../../../expressions.html#header.boost.log.expressions.attr_fwd_hpp" title="Header <boost/log/expressions/attr_fwd.hpp>">boost/log/expressions/attr_fwd.hpp</a>> 26 27</span><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">,</span> <span class="keyword">typename</span> FallbackPolicyT<span class="special">,</span> <span class="keyword">typename</span> TagT<span class="special">,</span> 28 <span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="special">></span> <span class="keyword">class</span> ActorT<span class="special">></span> 29<span class="keyword">class</span> <a class="link" href="attribute_actor.html" title="Class template attribute_actor">attribute_actor</a> <span class="special">:</span> 30 <span class="keyword">public</span> <span class="identifier">ActorT</span><span class="special"><</span> <span class="identifier">attribute_terminal</span><span class="special"><</span> <span class="identifier">T</span><span class="special">,</span> <span class="identifier">FallbackPolicyT</span><span class="special">,</span> <span class="identifier">TagT</span> <span class="special">></span> <span class="special">></span> 31<span class="special">{</span> 32<span class="keyword">public</span><span class="special">:</span> 33 <span class="comment">// <a class="link" href="attribute_actor.html#boost.log.expressions.attribute_actorconstruct-copy-destruct">construct/copy/destruct</a></span> 34 <span class="keyword">explicit</span> <a class="link" href="attribute_actor.html#idm46079580819472-bb"><span class="identifier">attribute_actor</span></a><span class="special">(</span><span class="identifier">base_type</span> <span class="keyword">const</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 35 36 <span class="comment">// <a class="link" href="attribute_actor.html#idm46079580551552-bb">public member functions</a></span> 37 <span class="identifier">attribute_name</span> <a class="link" href="attribute_actor.html#idm46079580550992-bb"><span class="identifier">get_name</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 38 <span class="identifier">fallback_policy</span> <span class="keyword">const</span> <span class="special">&</span> <a class="link" href="attribute_actor.html#idm46079580548880-bb"><span class="identifier">get_fallback_policy</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 39 <span class="identifier">or_none_result_type</span> <a class="link" href="attribute_actor.html#idm46079580546752-bb"><span class="identifier">or_none</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 40 <span class="identifier">or_throw_result_type</span> <a class="link" href="attribute_actor.html#idm46079580824176-bb"><span class="identifier">or_throw</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 41 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> DefaultT<span class="special">></span> 42 <a class="link" href="attribute_actor.html" title="Class template attribute_actor">attribute_actor</a><span class="special"><</span> <span class="identifier">value_type</span><span class="special">,</span> <span class="identifier">fallback_to_default</span><span class="special"><</span> <span class="identifier">DefaultT</span> <span class="special">></span><span class="special">,</span> <span class="identifier">tag_type</span><span class="special">,</span> <span class="identifier">ActorT</span> <span class="special">></span> 43 <a class="link" href="attribute_actor.html#idm46079580822800-bb"><span class="identifier">or_default</span></a><span class="special">(</span><span class="identifier">DefaultT</span> <span class="keyword">const</span> <span class="special">&</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 44<span class="special">}</span><span class="special">;</span></pre></div> 45<div class="refsect1"> 46<a name="idm44984878894592"></a><h2>Description</h2> 47<p>An attribute value extraction terminal actor </p> 48<div class="refsect2"> 49<a name="idm44984878893920"></a><h3> 50<a name="boost.log.expressions.attribute_actorconstruct-copy-destruct"></a><code class="computeroutput">attribute_actor</code> 51 public 52 construct/copy/destruct</h3> 53<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"> 54<pre class="literallayout"><span class="keyword">explicit</span> <a name="idm46079580819472-bb"></a><span class="identifier">attribute_actor</span><span class="special">(</span><span class="identifier">base_type</span> <span class="keyword">const</span> <span class="special">&</span> act<span class="special">)</span><span class="special">;</span></pre>Initializing constructor. </li></ol></div> 55</div> 56<div class="refsect2"> 57<a name="idm44984878885312"></a><h3> 58<a name="idm46079580551552-bb"></a><code class="computeroutput">attribute_actor</code> public member functions</h3> 59<div class="orderedlist"><ol class="orderedlist" type="1"> 60<li class="listitem"> 61<pre class="literallayout"><span class="identifier">attribute_name</span> <a name="idm46079580550992-bb"></a><span class="identifier">get_name</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre> 62<p> 63</p> 64<div class="variablelist"><table border="0" class="variablelist compact"> 65<colgroup> 66<col align="left" valign="top"> 67<col> 68</colgroup> 69<tbody><tr> 70<td><p><span class="term">Returns:</span></p></td> 71<td><p>The attribute name </p></td> 72</tr></tbody> 73</table></div> 74</li> 75<li class="listitem"> 76<pre class="literallayout"><span class="identifier">fallback_policy</span> <span class="keyword">const</span> <span class="special">&</span> <a name="idm46079580548880-bb"></a><span class="identifier">get_fallback_policy</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre> 77<p> 78</p> 79<div class="variablelist"><table border="0" class="variablelist compact"> 80<colgroup> 81<col align="left" valign="top"> 82<col> 83</colgroup> 84<tbody><tr> 85<td><p><span class="term">Returns:</span></p></td> 86<td><p>Fallback policy </p></td> 87</tr></tbody> 88</table></div> 89</li> 90<li class="listitem"> 91<pre class="literallayout"><span class="identifier">or_none_result_type</span> <a name="idm46079580546752-bb"></a><span class="identifier">or_none</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>Generates an expression that extracts the attribute value or a default value. </li> 92<li class="listitem"> 93<pre class="literallayout"><span class="identifier">or_throw_result_type</span> <a name="idm46079580824176-bb"></a><span class="identifier">or_throw</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>Generates an expression that extracts the attribute value or throws an exception. </li> 94<li class="listitem"> 95<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> DefaultT<span class="special">></span> 96 <a class="link" href="attribute_actor.html" title="Class template attribute_actor">attribute_actor</a><span class="special"><</span> <span class="identifier">value_type</span><span class="special">,</span> <span class="identifier">fallback_to_default</span><span class="special"><</span> <span class="identifier">DefaultT</span> <span class="special">></span><span class="special">,</span> <span class="identifier">tag_type</span><span class="special">,</span> <span class="identifier">ActorT</span> <span class="special">></span> 97 <a name="idm46079580822800-bb"></a><span class="identifier">or_default</span><span class="special">(</span><span class="identifier">DefaultT</span> <span class="keyword">const</span> <span class="special">&</span> def_val<span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>Generates an expression that extracts the attribute value or a default value. </li> 98</ol></div> 99</div> 100</div> 101</div> 102<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 103<td align="left"></td> 104<td align="right"><div class="copyright-footer">Copyright © 2007-2019 Andrey Semashev<p> 105 Distributed under the Boost Software License, Version 1.0. (See accompanying 106 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>). 107 </p> 108</div></td> 109</tr></table> 110<hr> 111<div class="spirit-nav"> 112<a accesskey="p" href="attr_idm46079581363536.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../../expressions.html#header.boost.log.expressions.attr_fwd_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="attribute_terminal.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 113</div> 114</body> 115</html> 116
