1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Function make_old</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="null_old.html" title="Function null_old"> 10<link rel="next" href="make_old_idm46268584770704.html" title="Function make_old"> 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="null_old.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="make_old_idm46268584770704.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="refentry"> 26<a name="boost.contract.make_old_idm46268584781184"></a><div class="titlepage"></div> 27<div class="refnamediv"> 28<h2><span class="refentrytitle">Function make_old</span></h2> 29<p>boost::contract::make_old — Make an old value pointer (but not for virtual public functions and public functions overrides). </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<a class="link" href="old_pointer.html" title="Class old_pointer">old_pointer</a> <span class="identifier">make_old</span><span class="special">(</span><a class="link" href="old_value.html" title="Class old_value">old_value</a> <span class="keyword">const</span> <span class="special">&</span> old<span class="special">)</span><span class="special">;</span></pre></div> 36<div class="refsect1"> 37<a name="idm45988676997952"></a><h2>Description</h2> 38<p>The related old value pointer will not be null if the specified old value was actually copied. This function is usually only called by code expanded by <code class="computeroutput">BOOST_CONTRACT_OLDOF(old_expr)</code> as in:</p> 39<pre class="programlisting"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">contract</span><span class="special">::</span><span class="identifier">make_old</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">contract</span><span class="special">::</span><span class="identifier">copy_old</span><span class="special">(</span><span class="special">)</span> <span class="special">?</span> <span class="identifier">old_expr</span> <span class="special">:</span> 40 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">contract</span><span class="special">::</span><span class="identifier">null_old</span><span class="special">(</span><span class="special">)</span><span class="special">)</span> 41</pre> 42<p><span class="bold"><strong>See Also:</strong></span></p> 43<p> <a class="link" href="../../boost_contract/extras.html#boost_contract.extras.no_macros__and_no_variadic_macros_" title="No Macros (and No Variadic Macros)"> No Macros</a></p> 44<p> 45</p> 46<p> 47 48 49</p> 50<div class="variablelist"><table border="0" class="variablelist compact"> 51<colgroup> 52<col align="left" valign="top"> 53<col> 54</colgroup> 55<tbody> 56<tr> 57<td><p><span class="term">Parameters:</span></p></td> 58<td><div class="variablelist"><table border="0" class="variablelist compact"> 59<colgroup> 60<col align="left" valign="top"> 61<col> 62</colgroup> 63<tbody><tr> 64<td><p><span class="term"><code class="computeroutput">old</code></span></p></td> 65<td><p>Old value which is usually implicitly constructed from the user old value expression to be copied (use the ternary operator <code class="computeroutput">?:</code> to completely avoid to evaluate the old value expression when <code class="computeroutput">boost::contract::copy_old()</code> is <code class="computeroutput">false</code>).</p></td> 66</tr></tbody> 67</table></div></td> 68</tr> 69<tr> 70<td><p><span class="term">Returns:</span></p></td> 71<td><p>Old value pointer (usually implicitly converted to either <code class="computeroutput"><a class="link" href="old_ptr.html" title="Class template old_ptr">boost::contract::old_ptr</a></code> or <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> in user code). </p></td> 72</tr> 73</tbody> 74</table></div> 75</div> 76</div> 77<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 78<td align="left"></td> 79<td align="right"><div class="copyright-footer">Copyright © 2008-2019 Lorenzo Caminiti<p> 80 Distributed under the Boost Software License, Version 1.0 (see accompanying 81 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>) 82 </p> 83</div></td> 84</tr></table> 85<hr> 86<div class="spirit-nav"> 87<a accesskey="p" href="null_old.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="make_old_idm46268584770704.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 88</div> 89</body> 90</html> 91
