1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<head> 4<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 5<title>Class template visitor_ptr_t</title> 6<link rel="stylesheet" href="../../../doc/src/boostbook.css" type="text/css"> 7<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 8<link rel="home" href="../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> 9<link rel="up" href="../variant/reference.html#header.boost.variant.visitor_ptr_hpp" title="Header <boost/variant/visitor_ptr.hpp>"> 10<link rel="prev" href="static_visitor.html" title="Class template static_visitor"> 11<link rel="next" href="visitor_ptr.html" title="Function template visitor_ptr"> 12</head> 13<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 14<table cellpadding="2" width="100%"><tr> 15<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" 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class="titlepage"></div> 28<div class="refnamediv"> 29<h2><span class="refentrytitle">Class template visitor_ptr_t</span></h2> 30<p>boost::visitor_ptr_t — Adapts a function pointer for use as a static visitor.</p> 31</div> 32<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> 33<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="../variant/reference.html#header.boost.variant.visitor_ptr_hpp" title="Header <boost/variant/visitor_ptr.hpp>">boost/variant/visitor_ptr.hpp</a>> 34 35</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> R<span class="special">></span> 36<span class="keyword">class</span> <a class="link" href="visitor_ptr_t.html" title="Class template visitor_ptr_t">visitor_ptr_t</a> <span class="special">:</span> <span class="keyword">public</span> <a class="link" href="static_visitor.html" title="Class template static_visitor">static_visitor</a><span class="special"><</span><span class="identifier">R</span><span class="special">></span> <span class="special">{</span> 37<span class="keyword">public</span><span class="special">:</span> 38 <span class="comment">// <a class="link" href="visitor_ptr_t.html#boost.visitor_ptr_tconstruct-copy-destruct">construct/copy/destruct</a></span> 39 <span class="keyword">explicit</span> <a class="link" href="visitor_ptr_t.html#id-1_3_46_5_13_1_1_5-bb"><span class="identifier">visitor_ptr_t</span></a><span class="special">(</span><span class="identifier">R</span> <span class="special">(</span><span class="special">*</span><span class="special">)</span><span class="special">(</span><span class="identifier">T</span><span class="special">)</span><span class="special">)</span><span class="special">;</span> 40 41 <span class="comment">// <a class="link" href="visitor_ptr_t.html#id-1_3_46_5_13_1_1_6-bb">static visitor interfaces</a></span> 42 <span class="identifier">R</span> <a class="link" href="visitor_ptr_t.html#id-1_3_46_5_13_1_1_6_1_1-bb"><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span></a><span class="special">(</span><span class="emphasis"><em><span class="identifier">unspecified</span><span class="special">-</span><span class="identifier">forwarding</span><span class="special">-</span><span class="identifier">type</span></em></span><span class="special">)</span><span class="special">;</span> 43 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> U<span class="special">></span> <span class="keyword">void</span> <a class="link" href="visitor_ptr_t.html#id-1_3_46_5_13_1_1_6_1_2-bb"><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">U</span><span class="special">&</span><span class="special">)</span><span class="special">;</span> 44<span class="special">}</span><span class="special">;</span></pre></div> 45<div class="refsect1"> 46<a name="id-1.3.46.5.14.3.4"></a><h2>Description</h2> 47<p>Adapts the function given at construction for use as a 48 <a class="link" href="../variant/reference.html#variant.concepts.static-visitor" title="StaticVisitor">static visitor</a> 49 of type <code class="computeroutput">T</code> with result type <code class="computeroutput">R</code>.</p> 50<div class="refsect2"> 51<a name="id-1.3.46.5.14.3.4.3"></a><h3> 52<a name="boost.visitor_ptr_tconstruct-copy-destruct"></a><code class="computeroutput">visitor_ptr_t</code> 53 public 54 construct/copy/destruct</h3> 55<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"> 56<pre class="literallayout"><span class="keyword">explicit</span> <a name="id-1_3_46_5_13_1_1_5-bb"></a><span class="identifier">visitor_ptr_t</span><span class="special">(</span><span class="identifier">R</span> <span class="special">(</span><span class="special">*</span><span class="special">)</span><span class="special">(</span><span class="identifier">T</span><span class="special">)</span><span class="special">)</span><span class="special">;</span></pre> 57<div class="variablelist"><table border="0" class="variablelist compact"> 58<colgroup> 59<col align="left" valign="top"> 60<col> 61</colgroup> 62<tbody><tr> 63<td><p><span class="term">Effects:</span></p></td> 64<td>Constructs the visitor with the given function.</td> 65</tr></tbody> 66</table></div> 67</li></ol></div> 68</div> 69<div class="refsect2"> 70<a name="id-1.3.46.5.14.3.4.4"></a><h3> 71<a name="id-1_3_46_5_13_1_1_6-bb"></a><code class="computeroutput">visitor_ptr_t</code> static visitor interfaces</h3> 72<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"> 73<pre class="literallayout"><a name="id-1_3_46_5_13_1_1_6_1-bb"></a><span class="identifier">R</span> <a name="id-1_3_46_5_13_1_1_6_1_1-bb"></a><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span><span class="special">(</span><span class="emphasis"><em><span class="identifier">unspecified</span><span class="special">-</span><span class="identifier">forwarding</span><span class="special">-</span><span class="identifier">type</span></em></span> operand<span class="special">)</span><span class="special">;</span> 74<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> U<span class="special">></span> <span class="keyword">void</span> <a name="id-1_3_46_5_13_1_1_6_1_2-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="identifier">U</span><span class="special">&</span><span class="special">)</span><span class="special">;</span></pre> 75<div class="variablelist"><table border="0" class="variablelist compact"> 76<colgroup> 77<col align="left" valign="top"> 78<col> 79</colgroup> 80<tbody> 81<tr> 82<td><p><span class="term">Effects:</span></p></td> 83<td>If passed a value or reference of type 84 <code class="computeroutput">T</code>, it invokes the function given at 85 construction, appropriately forwarding 86 <code class="computeroutput">operand</code>.</td> 87</tr> 88<tr> 89<td><p><span class="term">Returns:</span></p></td> 90<td>Returns the result of the function invocation.</td> 91</tr> 92<tr> 93<td><p><span class="term">Throws:</span></p></td> 94<td>The overload taking a value or reference of type 95 <code class="computeroutput">T</code> throws if the invoked function throws. 96 The overload taking all other values <span class="emphasis"><em>always</em></span> 97 throws <code class="computeroutput"><a class="link" href="bad_visit.html" title="Class bad_visit">bad_visit</a></code>.</td> 98</tr> 99</tbody> 100</table></div> 101</li></ol></div> 102</div> 103</div> 104</div> 105<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 106<td align="left"></td> 107<td align="right"><div class="copyright-footer">Copyright © 2002, 2003 Eric Friedman, Itay Maman<br>Copyright © 2014-2020 Antony Polukhin<p>Distributed under the Boost Software License, Version 1.0. 108 (See accompanying file <code class="filename">LICENSE_1_0.txt</code> or copy at 109 <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) 110 </p> 111</div></td> 112</tr></table> 113<hr> 114<div class="spirit-nav"> 115<a accesskey="p" href="static_visitor.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../variant/reference.html#header.boost.variant.visitor_ptr_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="visitor_ptr.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> 116</div> 117</body> 118</html> 119
