1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Function template constructor</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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href="check.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../reference.html#header.boost.contract.constructor_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="access.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="refentry"> 26<a name="boost.contract.constructor"></a><div class="titlepage"></div> 27<div class="refnamediv"> 28<h2><span class="refentrytitle">Function template constructor</span></h2> 29<p>boost::contract::constructor — Program contracts for constructors. </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.constructor_hpp" title="Header <boost/contract/constructor.hpp>">boost/contract/constructor.hpp</a>> 33 34</span> 35<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Class<span class="special">></span> 36 <a class="link" href="specify__idm46268585058320.html" title="Class template specify_old_postcondition_except">specify_old_postcondition_except</a> <span class="identifier">constructor</span><span class="special">(</span><span class="identifier">Class</span> <span class="special">*</span> obj<span class="special">)</span><span class="special">;</span></pre></div> 37<div class="refsect1"> 38<a name="idm45988680057232"></a><h2>Description</h2> 39<p>This is used to specify postconditions, exception guarantees, old value copies at body, and check class invariants for constructors (see <code class="computeroutput"><code class="computeroutput"><a class="link" href="constructor_precondition.html" title="Class template constructor_precondition">boost::contract::constructor_precondition</a></code></code> to specify preconditions for constructors):</p> 40<pre class="programlisting"><span class="keyword">class</span> <span class="identifier">u</span> <span class="special">{</span> 41 <span class="keyword">friend</span> <span class="keyword">class</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">contract</span><span class="special">:</span><span class="identifier">access</span><span class="special">;</span> 42 43 <span class="keyword">void</span> <span class="identifier">invariant</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">{</span> <span class="comment">// Optional (as for static and volatile).</span> 44 <span class="identifier">BOOST_CONTRACT_ASSERT</span><span class="special">(</span><span class="special">...</span><span class="special">)</span><span class="special">;</span> 45 <span class="special">...</span> 46 <span class="special">}</span> 47 48<span class="keyword">public</span><span class="special">:</span> 49 <span class="identifier">u</span><span class="special">(</span><span class="special">...</span><span class="special">)</span> <span class="special">{</span> 50 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">contract</span><span class="special">::</span><span class="identifier">old_ptr</span><span class="special"><</span><span class="identifier">old_type</span><span class="special">></span> <span class="identifier">old_var</span><span class="special">;</span> 51 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">contract</span><span class="special">::</span><span class="identifier">check</span> <span class="identifier">c</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">constructor</span><span class="special">(</span><span class="keyword">this</span><span class="special">)</span> 52 <span class="comment">// No `.precondition` (use `constructor_precondition` instead).</span> 53 <span class="special">.</span><span class="identifier">old</span><span class="special">(</span><span class="special">[</span><span class="special">&</span><span class="special">]</span> <span class="special">{</span> <span class="comment">// Optional.</span> 54 <span class="identifier">old_var</span> <span class="special">=</span> <span class="identifier">BOOST_CONTRACT_OLDOF</span><span class="special">(</span><span class="identifier">old_expr</span><span class="special">)</span><span class="special">;</span> 55 <span class="special">...</span> 56 <span class="special">}</span><span class="special">)</span> 57 <span class="special">.</span><span class="identifier">postcondition</span><span class="special">(</span><span class="special">[</span><span class="special">&</span><span class="special">]</span> <span class="special">{</span> <span class="comment">// Optional.</span> 58 <span class="identifier">BOOST_CONTRACT_ASSERT</span><span class="special">(</span><span class="special">...</span><span class="special">)</span><span class="special">;</span> 59 <span class="special">...</span> 60 <span class="special">}</span><span class="special">)</span> 61 <span class="special">.</span><span class="identifier">except</span><span class="special">(</span><span class="special">[</span><span class="special">&</span><span class="special">]</span> <span class="special">{</span> <span class="comment">// Optional.</span> 62 <span class="identifier">BOOST_CONTRACT_ASSERT</span><span class="special">(</span><span class="special">...</span><span class="special">)</span><span class="special">;</span> 63 <span class="special">...</span> 64 <span class="special">}</span><span class="special">)</span> 65 <span class="special">;</span> 66 67 <span class="special">...</span> <span class="comment">// Constructor body.</span> 68 <span class="special">}</span> 69 70 <span class="special">...</span> 71<span class="special">}</span><span class="special">;</span> 72</pre> 73<p>For optimization, this can be omitted for constructors that do not have postconditions and exception guarantees, within classes that have no invariants.</p> 74<p><span class="bold"><strong>See Also:</strong></span></p> 75<p> <a class="link" href="../../boost_contract/tutorial.html#boost_contract.tutorial.constructors" title="Constructors"> Constructors</a></p> 76<p> 77</p> 78<p> 79 80 81 82</p> 83<div class="variablelist"><table border="0" class="variablelist compact"> 84<colgroup> 85<col align="left" valign="top"> 86<col> 87</colgroup> 88<tbody> 89<tr> 90<td><p><span class="term">Parameters:</span></p></td> 91<td><div class="variablelist"><table border="0" class="variablelist compact"> 92<colgroup> 93<col align="left" valign="top"> 94<col> 95</colgroup> 96<tbody><tr> 97<td><p><span class="term"><code class="computeroutput">obj</code></span></p></td> 98<td><p>The object <code class="computeroutput">this</code> from the scope of the enclosing constructor declaring the contract. (Constructors check all class invariants, including static and volatile invariants, see <a class="link" href="../../boost_contract/tutorial.html#boost_contract.tutorial.class_invariants" title="Class Invariants"> 99 Class Invariants</a> and <a class="link" href="../../boost_contract/extras.html#boost_contract.extras.volatile_public_functions" title="Volatile Public Functions"> 100 Volatile Public Functions</a>).</p></td> 101</tr></tbody> 102</table></div></td> 103</tr> 104<tr> 105<td><p><span class="term">Template Parameters:</span></p></td> 106<td><div class="variablelist"><table border="0" class="variablelist compact"> 107<colgroup> 108<col align="left" valign="top"> 109<col> 110</colgroup> 111<tbody><tr> 112<td><p><span class="term"><code class="computeroutput">Class</code></span></p></td> 113<td><p>The type of the class containing the constructor declaring the contract. (Usually this template parameter is automatically deduced by C++ and it does not need to be explicitly specified by programmers.)</p></td> 114</tr></tbody> 115</table></div></td> 116</tr> 117<tr> 118<td><p><span class="term">Returns:</span></p></td> 119<td><p>The result of this function must be assigned to a variable of type <code class="computeroutput"><a class="link" href="check.html" title="Class check">boost::contract::check</a></code> declared explicitly (i.e., without using C++11 <code class="computeroutput">auto</code> declarations) and locally just before the code of the constructor body (otherwise this library will generate a run-time error, see <code class="computeroutput"><a class="link" href="../../BOOST_CO_idm46268585506528.html" title="Macro BOOST_CONTRACT_ON_MISSING_CHECK_DECL">BOOST_CONTRACT_ON_MISSING_CHECK_DECL</a></code>). </p></td> 120</tr> 121</tbody> 122</table></div> 123</div> 124</div> 125<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 126<td align="left"></td> 127<td align="right"><div class="copyright-footer">Copyright © 2008-2019 Lorenzo Caminiti<p> 128 Distributed under the Boost Software License, Version 1.0 (see accompanying 129 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>) 130 </p> 131</div></td> 132</tr></table> 133<hr> 134<div class="spirit-nav"> 135<a accesskey="p" href="check.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../reference.html#header.boost.contract.constructor_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="access.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 136</div> 137</body> 138</html> 139
