1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Struct template is_old_value_copyable</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. 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A copyable old value type <code class="computeroutput">V</code> is always copied using <code class="computeroutput">boost::contract::old_value_copy<V></code>. A non-copyable old value type <code class="computeroutput">W</code> generates a compile-time error when <code class="computeroutput">boost::contract::old_ptr<W></code> is dereferenced, but instead leaves <code class="computeroutput">boost::contract::old_ptr_if_copyable<W></code> always null (without generating compile-time errors).</p> 48<p><span class="bold"><strong>See Also:</strong></span></p> 49<p> <a class="link" href="../../boost_contract/extras.html#boost_contract.extras.old_value_requirements__templates_" title="Old Value Requirements (Templates)"> 50 Old Value Requirements</a> </p> 51<p> 52</p> 53<p> 54</p> 55</div> 56</div> 57<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 58<td align="left"></td> 59<td align="right"><div class="copyright-footer">Copyright © 2008-2019 Lorenzo Caminiti<p> 60 Distributed under the Boost Software License, Version 1.0 (see accompanying 61 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>) 62 </p> 63</div></td> 64</tr></table> 65<hr> 66<div class="spirit-nav"> 67<a accesskey="p" href="function.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_pointer.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 68</div> 69</body> 70</html> 71
