| <html> |
| <head> |
| <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> |
| <title>Function template extract</title> |
| <link rel="stylesheet" href="../../../../../../doc/src/boostbook.css" type="text/css"> |
| <meta name="generator" content="DocBook XSL Stylesheets V1.78.1"> |
| <link rel="home" href="../../index.html" title="Chapter 1. Boost.Log v2"> |
| <link rel="up" href="../../attributes.html#header.boost.log.attributes.value_extraction_hpp" title="Header <boost/log/attributes/value_extraction.hpp>"> |
| <link rel="prev" href="extract_or_def_idp42437568.html" title="Function template extract_or_default"> |
| <link rel="next" href="extract_idp42452688.html" title="Function template extract"> |
| </head> |
| <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> |
| <table cellpadding="2" width="100%"><tr><td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../boost.png"></td></tr></table> |
| <hr> |
| <div class="spirit-nav"> |
| <a accesskey="p" href="extract_or_def_idp42437568.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../attributes.html#header.boost.log.attributes.value_extraction_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="extract_idp42452688.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> |
| </div> |
| <div class="refentry"> |
| <a name="boost.log.extract_idp42445392"></a><div class="titlepage"></div> |
| <div class="refnamediv"> |
| <h2><span class="refentrytitle">Function template extract</span></h2> |
| <p>boost::log::extract</p> |
| </div> |
| <h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> |
| <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="../../attributes.html#header.boost.log.attributes.value_extraction_hpp" title="Header <boost/log/attributes/value_extraction.hpp>">boost/log/attributes/value_extraction.hpp</a>> |
| |
| </span> |
| <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> DescriptorT<span class="special">,</span> <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> |
| <a class="link" href="result_of/extract.html" title="Struct template extract">result_of::extract</a><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">DescriptorT</span><span class="special">::</span><span class="identifier">value_type</span><span class="special">,</span> <span class="identifier">DescriptorT</span> <span class="special">></span><span class="special">::</span><span class="identifier">type</span> |
| <span class="identifier">extract</span><span class="special">(</span><span class="identifier">expressions</span><span class="special">::</span><span class="identifier">attribute_keyword</span><span class="special"><</span> <span class="identifier">DescriptorT</span><span class="special">,</span> <span class="identifier">ActorT</span> <span class="special">></span> <span class="keyword">const</span> <span class="special">&</span> keyword<span class="special">,</span> |
| <a class="link" href="attribute_value_set.html" title="Class attribute_value_set">attribute_value_set</a> <span class="keyword">const</span> <span class="special">&</span> attrs<span class="special">)</span><span class="special">;</span></pre></div> |
| <div class="refsect1"> |
| <a name="idp110160112"></a><h2>Description</h2> |
| <p>The function extracts an attribute value from the view. The user has to explicitly specify the type or set of possible types of the attribute value to be extracted.</p> |
| <p> |
| |
| </p> |
| <div class="variablelist"><table border="0" class="variablelist compact"> |
| <colgroup> |
| <col align="left" valign="top"> |
| <col> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td><p><span class="term">Parameters:</span></p></td> |
| <td><div class="variablelist"><table border="0" class="variablelist compact"> |
| <colgroup> |
| <col align="left" valign="top"> |
| <col> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><code class="computeroutput">attrs</code></span></p></td> |
| <td><p>A set of attribute values in which to look for the specified attribute value. </p></td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><code class="computeroutput">keyword</code></span></p></td> |
| <td><p>The keyword of the attribute value to extract. </p></td> |
| </tr> |
| </tbody> |
| </table></div></td> |
| </tr> |
| <tr> |
| <td><p><span class="term">Returns:</span></p></td> |
| <td><p>A <code class="computeroutput">value_ref</code> that refers to the extracted value, if found. An empty value otherwise. </p></td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| </div> |
| <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> |
| <td align="left"></td> |
| <td align="right"><div class="copyright-footer">Copyright © 2007-2015 Andrey |
| Semashev<p> |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| 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>). |
| </p> |
| </div></td> |
| </tr></table> |
| <hr> |
| <div class="spirit-nav"> |
| <a accesskey="p" href="extract_or_def_idp42437568.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../attributes.html#header.boost.log.attributes.value_extraction_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="extract_idp42452688.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> |
| </div> |
| </body> |
| </html> |
