1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Class old_pointer</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.Contract 1.0.0"> 8<link rel="up" href="../../reference.html#header.boost.contract.old_hpp" title="Header <boost/contract/old.hpp>"> 9<link rel="prev" href="is_old_value_copyable.html" title="Struct template is_old_value_copyable"> 10<link rel="next" href="old_ptr.html" title="Class template old_ptr"> 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="is_old_value_copyable.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../reference.html#header.boost.contract.old_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="old_ptr.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="refentry"> 26<a name="boost.contract.old_pointer"></a><div class="titlepage"></div> 27<div class="refnamediv"> 28<h2><span class="refentrytitle">Class old_pointer</span></h2> 29<p>boost::contract::old_pointer — Convert old value copies into old value pointers. </p> 30</div> 31<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> 32<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="../../reference.html#header.boost.contract.old_hpp" title="Header <boost/contract/old.hpp>">boost/contract/old.hpp</a>> 33 34</span> 35<span class="keyword">class</span> <a class="link" href="old_pointer.html" title="Class old_pointer">old_pointer</a> <span class="special">{</span> 36<span class="keyword">public</span><span class="special">:</span> 37 38 <span class="comment">// <a class="link" href="old_pointer.html#idm46268584887296-bb">public member functions</a></span> 39 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> <a class="link" href="old_pointer.html#idm46268584886736-bb"><span class="keyword">operator</span> <span class="identifier">old_ptr_if_copyable</span><span class="special"><</span> <span class="identifier">T</span> <span class="special">></span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span> 40 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> <a class="link" href="old_pointer.html#idm46268584881104-bb"><span class="keyword">operator</span> <span class="identifier">old_ptr</span><span class="special"><</span> <span class="identifier">T</span> <span class="special">></span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span> 41<span class="special">}</span><span class="special">;</span></pre></div> 42<div class="refsect1"> 43<a name="idm45988677515104"></a><h2>Description</h2> 44<p>This class is usually only implicitly used by this library and it does not explicitly appear in user code (that is why this class does not have public constructors, etc.). </p> 45<div class="refsect2"> 46<a name="idm45988677514240"></a><h3> 47<a name="idm46268584887296-bb"></a><code class="computeroutput">old_pointer</code> public member functions</h3> 48<div class="orderedlist"><ol class="orderedlist" type="1"> 49<li class="listitem"> 50<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> <a name="idm46268584886736-bb"></a><span class="keyword">operator</span> <span class="identifier">old_ptr_if_copyable</span><span class="special"><</span> <span class="identifier">T</span> <span class="special">></span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre>Convert this object to an actual old value pointer for which the old value type <code class="computeroutput">T</code> might or not be copyable. <p>For example, this is implicitly called when assigning or initializing old value pointers of type <code class="computeroutput"><code class="computeroutput"><a class="link" href="old_ptr_if_copyable.html" title="Class template old_ptr_if_copyable">boost::contract::old_ptr_if_copyable</a></code></code>.</p> 51<p> 52</p> 53<div class="variablelist"><table border="0" class="variablelist compact"> 54<colgroup> 55<col align="left" valign="top"> 56<col> 57</colgroup> 58<tbody><tr> 59<td><p><span class="term">Template Parameters:</span></p></td> 60<td><div class="variablelist"><table border="0" class="variablelist compact"> 61<colgroup> 62<col align="left" valign="top"> 63<col> 64</colgroup> 65<tbody><tr> 66<td><p><span class="term"><code class="computeroutput">T</code></span></p></td> 67<td><p>Type of the pointed old value. The old value pointer will always be null if this type is not copyable (see <code class="computeroutput"><code class="computeroutput"><a class="link" href="is_old_value_copyable.html" title="Struct template is_old_value_copyable">boost::contract::is_old_value_copyable</a></code></code>), but this library will not generate a compile-time error. </p></td> 68</tr></tbody> 69</table></div></td> 70</tr></tbody> 71</table></div> 72</li> 73<li class="listitem"> 74<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> <a name="idm46268584881104-bb"></a><span class="keyword">operator</span> <span class="identifier">old_ptr</span><span class="special"><</span> <span class="identifier">T</span> <span class="special">></span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre>Convert this object to an actual old value pointer for which the old value type <code class="computeroutput">T</code> must be copyable. <p>For example, this is implicitly called when assigning or initializing old value pointers of type <code class="computeroutput"><code class="computeroutput"><a class="link" href="old_ptr.html" title="Class template old_ptr">boost::contract::old_ptr</a></code></code>.</p> 75<p> 76</p> 77<div class="variablelist"><table border="0" class="variablelist compact"> 78<colgroup> 79<col align="left" valign="top"> 80<col> 81</colgroup> 82<tbody><tr> 83<td><p><span class="term">Template Parameters:</span></p></td> 84<td><div class="variablelist"><table border="0" class="variablelist compact"> 85<colgroup> 86<col align="left" valign="top"> 87<col> 88</colgroup> 89<tbody><tr> 90<td><p><span class="term"><code class="computeroutput">T</code></span></p></td> 91<td><p>Type of the pointed old value. This type must be copyable (see <code class="computeroutput"><code class="computeroutput"><a class="link" href="is_old_value_copyable.html" title="Struct template is_old_value_copyable">boost::contract::is_old_value_copyable</a></code></code>), otherwise this library will generate a compile-time error when the old value pointer is dereferenced. </p></td> 92</tr></tbody> 93</table></div></td> 94</tr></tbody> 95</table></div> 96</li> 97</ol></div> 98</div> 99</div> 100</div> 101<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 102<td align="left"></td> 103<td align="right"><div class="copyright-footer">Copyright © 2008-2019 Lorenzo Caminiti<p> 104 Distributed under the Boost Software License, Version 1.0 (see accompanying 105 file LICENSE_1_0.txt or a copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) 106 </p> 107</div></td> 108</tr></table> 109<hr> 110<div class="spirit-nav"> 111<a accesskey="p" href="is_old_value_copyable.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../reference.html#header.boost.contract.old_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="old_ptr.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 112</div> 113</body> 114</html> 115
