1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>invoke_function_object</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="../functions.html" title="Functions"> 9<link rel="prev" href="invoke_proc.html" title="invoke_procedure"> 10<link rel="next" href="../metafunctions.html" title="Metafunctions"> 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="invoke_proc.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../functions.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="../metafunctions.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h5 class="title"> 27<a name="fusion.functional.invocation.functions.invoke_fobj"></a><a class="link" href="invoke_fobj.html" title="invoke_function_object">invoke_function_object</a> 28</h5></div></div></div> 29<h6> 30<a name="fusion.functional.invocation.functions.invoke_fobj.h0"></a> 31 <span class="phrase"><a name="fusion.functional.invocation.functions.invoke_fobj.description"></a></span><a class="link" href="invoke_fobj.html#fusion.functional.invocation.functions.invoke_fobj.description">Description</a> 32 </h6> 33<p> 34 Calls a <a class="link" href="../../concepts/poly.html" title="Polymorphic Function Object">Polymorphic Function 35 Object</a> with the arguments from a <a class="link" href="../../../sequence.html" title="Sequence">Sequence</a>. 36 </p> 37<p> 38 The first template parameter can be specialized explicitly to avoid copying 39 and/or to control the const qualification of a function object. 40 </p> 41<p> 42 Constructors can be called applying <a href="http://www.boost.org/libs/functional/factory" target="_top">Boost.Functional/Factory 43 Library</a>. 44 </p> 45<h6> 46<a name="fusion.functional.invocation.functions.invoke_fobj.h1"></a> 47 <span class="phrase"><a name="fusion.functional.invocation.functions.invoke_fobj.synopsis"></a></span><a class="link" href="invoke_fobj.html#fusion.functional.invocation.functions.invoke_fobj.synopsis">Synopsis</a> 48 </h6> 49<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> 50 <span class="keyword">typename</span> <span class="identifier">Function</span><span class="special">,</span> 51 <span class="keyword">class</span> <span class="identifier">Sequence</span> 52 <span class="special">></span> 53<span class="keyword">typename</span> <a class="link" href="../metafunctions/invoke_fobj.html" title="invoke_function_object"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">invoke_function_object</span></code></a><span class="special"><</span><span class="identifier">Function</span><span class="special">,</span> <span class="identifier">Sequence</span><span class="special">>::</span><span class="identifier">type</span> 54<span class="identifier">invoke_function_object</span><span class="special">(</span><span class="identifier">Function</span> <span class="identifier">f</span><span class="special">,</span> <span class="identifier">Sequence</span> <span class="special">&</span> <span class="identifier">s</span><span class="special">);</span> 55 56<span class="keyword">template</span><span class="special"><</span> 57 <span class="keyword">typename</span> <span class="identifier">Function</span><span class="special">,</span> 58 <span class="keyword">class</span> <span class="identifier">Sequence</span> 59 <span class="special">></span> 60<span class="keyword">typename</span> <a class="link" href="../metafunctions/invoke_fobj.html" title="invoke_function_object"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">invoke_function_object</span></code></a><span class="special"><</span><span class="identifier">Function</span><span class="special">,</span> <span class="identifier">Sequence</span> <span class="keyword">const</span><span class="special">>::</span><span class="identifier">type</span> 61<span class="identifier">invoke_function_object</span><span class="special">(</span><span class="identifier">Function</span> <span class="identifier">f</span><span class="special">,</span> <span class="identifier">Sequence</span> <span class="keyword">const</span> <span class="special">&</span> <span class="identifier">s</span><span class="special">);</span> 62</pre> 63<h6> 64<a name="fusion.functional.invocation.functions.invoke_fobj.h2"></a> 65 <span class="phrase"><a name="fusion.functional.invocation.functions.invoke_fobj.parameters"></a></span><a class="link" href="invoke_fobj.html#fusion.functional.invocation.functions.invoke_fobj.parameters">Parameters</a> 66 </h6> 67<div class="informaltable"><table class="table"> 68<colgroup> 69<col> 70<col> 71<col> 72</colgroup> 73<thead><tr> 74<th> 75 <p> 76 Parameter 77 </p> 78 </th> 79<th> 80 <p> 81 Requirement 82 </p> 83 </th> 84<th> 85 <p> 86 Description 87 </p> 88 </th> 89</tr></thead> 90<tbody> 91<tr> 92<td> 93 <p> 94 <code class="computeroutput"><span class="identifier">f</span></code> 95 </p> 96 </td> 97<td> 98 <p> 99 Model of <a class="link" href="../../concepts/poly.html" title="Polymorphic Function Object">Polymorphic 100 Function Object</a> 101 </p> 102 </td> 103<td> 104 <p> 105 The function object to call. 106 </p> 107 </td> 108</tr> 109<tr> 110<td> 111 <p> 112 <code class="computeroutput"><span class="identifier">s</span></code> 113 </p> 114 </td> 115<td> 116 <p> 117 Model of <a class="link" href="../../../sequence/concepts/forward_sequence.html" title="Forward Sequence">Forward 118 Sequence</a> 119 </p> 120 </td> 121<td> 122 <p> 123 The arguments. 124 </p> 125 </td> 126</tr> 127</tbody> 128</table></div> 129<h6> 130<a name="fusion.functional.invocation.functions.invoke_fobj.h3"></a> 131 <span class="phrase"><a name="fusion.functional.invocation.functions.invoke_fobj.expression_semantics"></a></span><a class="link" href="invoke_fobj.html#fusion.functional.invocation.functions.invoke_fobj.expression_semantics">Expression 132 Semantics</a> 133 </h6> 134<pre class="programlisting"><span class="identifier">invoke_function_object</span><span class="special">(</span><span class="identifier">f</span><span class="special">,</span><span class="identifier">s</span><span class="special">);</span> 135</pre> 136<p> 137 <span class="bold"><strong>Return type</strong></span>: Return type of <code class="computeroutput"><span class="identifier">f</span></code> when invoked with the elements in 138 <code class="computeroutput"><span class="identifier">s</span></code> as its arguments. 139 </p> 140<p> 141 <span class="bold"><strong>Semantics</strong></span>: Invokes <code class="computeroutput"><span class="identifier">f</span></code> 142 with the elements in <code class="computeroutput"><span class="identifier">s</span></code> 143 as arguments and returns the result of the call expression. 144 </p> 145<h6> 146<a name="fusion.functional.invocation.functions.invoke_fobj.h4"></a> 147 <span class="phrase"><a name="fusion.functional.invocation.functions.invoke_fobj.header"></a></span><a class="link" href="invoke_fobj.html#fusion.functional.invocation.functions.invoke_fobj.header">Header</a> 148 </h6> 149<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">functional</span><span class="special">/</span><span class="identifier">invocation</span><span class="special">/</span><span class="identifier">invoke_function_object</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 150</pre> 151<h6> 152<a name="fusion.functional.invocation.functions.invoke_fobj.h5"></a> 153 <span class="phrase"><a name="fusion.functional.invocation.functions.invoke_fobj.example"></a></span><a class="link" href="invoke_fobj.html#fusion.functional.invocation.functions.invoke_fobj.example">Example</a> 154 </h6> 155<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">sub</span> 156<span class="special">{</span> 157 <span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Sig</span><span class="special">></span> 158 <span class="keyword">struct</span> <span class="identifier">result</span><span class="special">;</span> 159 160 <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">Self</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">T</span><span class="special">></span> 161 <span class="keyword">struct</span> <span class="identifier">result</span><span class="special"><</span> <span class="identifier">Self</span><span class="special">(</span><span class="identifier">T</span><span class="special">,</span><span class="identifier">T</span><span class="special">)</span> <span class="special">></span> 162 <span class="special">{</span> <span class="keyword">typedef</span> <span class="keyword">typename</span> <span class="identifier">remove_reference</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">type</span> <span class="identifier">type</span><span class="special">;</span> <span class="special">};</span> 163 164 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">></span> 165 <span class="identifier">T</span> <span class="keyword">operator</span><span class="special">()(</span><span class="identifier">T</span> <span class="identifier">lhs</span><span class="special">,</span> <span class="identifier">T</span> <span class="identifier">rhs</span><span class="special">)</span> <span class="keyword">const</span> 166 <span class="special">{</span> 167 <span class="keyword">return</span> <span class="identifier">lhs</span> <span class="special">-</span> <span class="identifier">rhs</span><span class="special">;</span> 168 <span class="special">}</span> 169<span class="special">};</span> 170 171<span class="keyword">void</span> <span class="identifier">try_it</span><span class="special">()</span> 172<span class="special">{</span> 173 <span class="identifier">sub</span> <span class="identifier">f</span><span class="special">;</span> 174 <span class="identifier">assert</span><span class="special">(</span><span class="identifier">f</span><span class="special">(</span><span class="number">2</span><span class="special">,</span><span class="number">1</span><span class="special">)</span> <span class="special">==</span> <span class="identifier">invoke_function_object</span><span class="special">(</span><span class="identifier">f</span><span class="special">,</span><a class="link" href="../../../container/generation/functions/make_vector.html" title="make_vector"><code class="computeroutput"><span class="identifier">make_vector</span></code></a><span class="special">(</span><span class="number">2</span><span class="special">,</span><span class="number">1</span><span class="special">)));</span> 175<span class="special">}</span> 176</pre> 177<h6> 178<a name="fusion.functional.invocation.functions.invoke_fobj.h6"></a> 179 <span class="phrase"><a name="fusion.functional.invocation.functions.invoke_fobj.see_also"></a></span><a class="link" href="invoke_fobj.html#fusion.functional.invocation.functions.invoke_fobj.see_also">See 180 also</a> 181 </h6> 182<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 183<li class="listitem"> 184 <a class="link" href="invoke.html" title="invoke"><code class="computeroutput"><span class="identifier">invoke</span></code></a> 185 </li> 186<li class="listitem"> 187 <a class="link" href="invoke_proc.html" title="invoke_procedure"><code class="computeroutput"><span class="identifier">invoke_procedure</span></code></a> 188 </li> 189<li class="listitem"> 190 <a class="link" href="../metafunctions/invoke_fobj.html" title="invoke_function_object"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">invoke_function_object</span></code></a> 191 </li> 192<li class="listitem"> 193 <a class="link" href="../../adapters/fused_function_object.html" title="fused_function_object"><code class="computeroutput"><span class="identifier">fused_function_object</span></code></a> 194 </li> 195<li class="listitem"> 196 <a class="link" href="../../generation/functions/mk_fused_fobj.html" title="make_fused_function_object"><code class="computeroutput"><span class="identifier">make_fused_function_object</span></code></a> 197 </li> 198</ul></div> 199</div> 200<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 201<td align="left"></td> 202<td align="right"><div class="copyright-footer">Copyright © 2001-2006, 2011, 2012 Joel de Guzman, 203 Dan Marsden, Tobias Schwinger<p> 204 Distributed under the Boost Software License, Version 1.0. (See accompanying 205 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>) 206 </p> 207</div></td> 208</tr></table> 209<hr> 210<div class="spirit-nav"> 211<a accesskey="p" href="invoke_proc.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../functions.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="../metafunctions.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 212</div> 213</body> 214</html> 215
