1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>value_of_data</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. Fusion 2.2"> 8<link rel="up" href="../metafunctions.html" title="Metafunctions"> 9<link rel="prev" href="key_of.html" title="key_of"> 10<link rel="next" href="deref_data.html" title="deref_data"> 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="key_of.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../metafunctions.html"><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="deref_data.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h4 class="title"> 27<a name="fusion.iterator.metafunctions.value_of_data"></a><a class="link" href="value_of_data.html" title="value_of_data">value_of_data</a> 28</h4></div></div></div> 29<h6> 30<a name="fusion.iterator.metafunctions.value_of_data.h0"></a> 31 <span class="phrase"><a name="fusion.iterator.metafunctions.value_of_data.description"></a></span><a class="link" href="value_of_data.html#fusion.iterator.metafunctions.value_of_data.description">Description</a> 32 </h6> 33<p> 34 Returns the type of the data property associated with the element referenced 35 by an associative iterator references. 36 </p> 37<h6> 38<a name="fusion.iterator.metafunctions.value_of_data.h1"></a> 39 <span class="phrase"><a name="fusion.iterator.metafunctions.value_of_data.synopsis"></a></span><a class="link" href="value_of_data.html#fusion.iterator.metafunctions.value_of_data.synopsis">Synopsis</a> 40 </h6> 41<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> 42 <span class="keyword">typename</span> <span class="identifier">I</span> 43 <span class="special">></span> 44<span class="keyword">struct</span> <span class="identifier">value_of_data</span> 45<span class="special">{</span> 46 <span class="keyword">typedef</span> <span class="emphasis"><em>unspecified</em></span> <span class="identifier">type</span><span class="special">;</span> 47<span class="special">};</span> 48</pre> 49<div class="table"> 50<a name="fusion.iterator.metafunctions.value_of_data.t0"></a><p class="title"><b>Table 1.20. Parameters</b></p> 51<div class="table-contents"><table class="table" summary="Parameters"> 52<colgroup> 53<col> 54<col> 55<col> 56</colgroup> 57<thead><tr> 58<th> 59 <p> 60 Parameter 61 </p> 62 </th> 63<th> 64 <p> 65 Requirement 66 </p> 67 </th> 68<th> 69 <p> 70 Description 71 </p> 72 </th> 73</tr></thead> 74<tbody><tr> 75<td> 76 <p> 77 <code class="computeroutput"><span class="identifier">I</span></code> 78 </p> 79 </td> 80<td> 81 <p> 82 Model of <a class="link" href="../concepts/associative_iterator.html" title="Associative Iterator">Associative 83 Iterator</a> 84 </p> 85 </td> 86<td> 87 <p> 88 Operation's argument 89 </p> 90 </td> 91</tr></tbody> 92</table></div> 93</div> 94<br class="table-break"><h6> 95<a name="fusion.iterator.metafunctions.value_of_data.h2"></a> 96 <span class="phrase"><a name="fusion.iterator.metafunctions.value_of_data.expression_semantics"></a></span><a class="link" href="value_of_data.html#fusion.iterator.metafunctions.value_of_data.expression_semantics">Expression 97 Semantics</a> 98 </h6> 99<pre class="programlisting"><a class="link" href="value_of_data.html" title="value_of_data"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">value_of_data</span></code></a><span class="special"><</span><span class="identifier">I</span><span class="special">>::</span><span class="identifier">type</span> 100</pre> 101<p> 102 <span class="bold"><strong>Return type</strong></span>: Any type 103 </p> 104<p> 105 <span class="bold"><strong>Semantics</strong></span>: Returns the type of the data 106 property associated with the element referenced by an associative iterator 107 <code class="computeroutput"><span class="identifier">I</span></code>. 108 </p> 109<h6> 110<a name="fusion.iterator.metafunctions.value_of_data.h3"></a> 111 <span class="phrase"><a name="fusion.iterator.metafunctions.value_of_data.header"></a></span><a class="link" href="value_of_data.html#fusion.iterator.metafunctions.value_of_data.header">Header</a> 112 </h6> 113<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">iterator</span><span class="special">/</span><span class="identifier">value_of_data</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 114<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">value_of_data</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 115</pre> 116<h6> 117<a name="fusion.iterator.metafunctions.value_of_data.h4"></a> 118 <span class="phrase"><a name="fusion.iterator.metafunctions.value_of_data.example"></a></span><a class="link" href="value_of_data.html#fusion.iterator.metafunctions.value_of_data.example">Example</a> 119 </h6> 120<pre class="programlisting"><span class="keyword">typedef</span> <a class="link" href="../../container/map.html" title="map"><code class="computeroutput"><span class="identifier">map</span></code></a><span class="special"><</span><a class="link" href="../../support/pair.html" title="pair"><code class="computeroutput"><span class="identifier">pair</span></code></a><span class="special"><</span><span class="keyword">float</span><span class="special">,</span><span class="keyword">int</span><span class="special">></span> <span class="special">></span> <span class="identifier">vec</span><span class="special">;</span> 121<span class="keyword">typedef</span> <a class="link" href="../../sequence/intrinsic/metafunctions/begin.html" title="begin"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">begin</span></code></a><span class="special"><</span><span class="identifier">vec</span><span class="special">>::</span><span class="identifier">type</span> <span class="identifier">first</span><span class="special">;</span> 122 123<span class="identifier">BOOST_MPL_ASSERT</span><span class="special">((</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">is_same</span><span class="special"><</span><a class="link" href="value_of_data.html" title="value_of_data"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">value_of_data</span></code></a><span class="special"><</span><span class="identifier">first</span><span class="special">>::</span><span class="identifier">type</span><span class="special">,</span> <span class="keyword">int</span><span class="special">>));</span> 124</pre> 125</div> 126<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 127<td align="left"></td> 128<td align="right"><div class="copyright-footer">Copyright © 2001-2006, 2011, 2012 Joel de Guzman, 129 Dan Marsden, Tobias Schwinger<p> 130 Distributed under the Boost Software License, Version 1.0. (See accompanying 131 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>) 132 </p> 133</div></td> 134</tr></table> 135<hr> 136<div class="spirit-nav"> 137<a accesskey="p" href="key_of.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../metafunctions.html"><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="deref_data.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 138</div> 139</body> 140</html> 141
