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25 <div class="refentry">
26 <a name="boost.contract.call_if__idm45395000002720"></a><div class="titlepage"></div>
27 <div class="refnamediv">
28 <h2><span class="refentrytitle">Struct template call_if_statement<true, Then, void></span></h2>
29 <p>boost::contract::call_if_statement<true, Then, void> — Template specialization to handle static predicates that are <code class="computeroutput">true</code> for then-branch functor template calls that return void (not needed on C++17 compilers, use <code class="computeroutput">if constexpr</code> instead). </p>
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.call_if_hpp" title="Header <boost/contract/call_if.hpp>">boost/contract/call_if.hpp</a>>
34 </span><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Then<span class="special">></span>
35 <span class="keyword">struct</span> <a class="link" href="call_if__idm45395000002720.html" title="Struct template call_if_statement<true, Then, void>">call_if_statement</a><span class="special"><</span><span class="keyword">true</span><span class="special">,</span> <span class="identifier">Then</span><span class="special">,</span> <span class="keyword">void</span><span class="special">></span> <span class="special">{</span>
36 <span class="comment">// <a class="link" href="call_if__idm45395000002720.html#boost.contract.call_if__idm45395000002720construct-copy-destruct">construct/copy/destruct</a></span>
37 <span class="keyword">explicit</span> <a class="link" href="call_if__idm45395000002720.html#idm45394999971152-bb"><span class="identifier">call_if_statement</span></a><span class="special">(</span><span class="identifier">Then</span><span class="special">)</span><span class="special">;</span>
39 <span class="comment">// <a class="link" href="call_if__idm45395000002720.html#idm45394999993936-bb">public member functions</a></span>
40 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Else<span class="special">></span> <span class="keyword">void</span> <a class="link" href="call_if__idm45395000002720.html#idm45394999993376-bb"><span class="identifier">else_</span></a><span class="special">(</span><span class="identifier">Else</span> <span class="keyword">const</span> <span class="special">&</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
41 <span class="keyword">template</span><span class="special"><</span><span class="keyword">bool</span> ElseIfPred<span class="special">,</span> <span class="keyword">typename</span> ElseIfThen<span class="special">></span>
42 <a class="link" href="call_if_statement.html" title="Struct template call_if_statement">call_if_statement</a><span class="special"><</span> <span class="keyword">true</span><span class="special">,</span> <span class="identifier">Then</span><span class="special">,</span> <span class="keyword">void</span> <span class="special">></span> <a class="link" href="call_if__idm45395000002720.html#idm45394999987552-bb"><span class="identifier">else_if_c</span></a><span class="special">(</span><span class="identifier">ElseIfThen</span> <span class="keyword">const</span> <span class="special">&</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
43 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> ElseIfPred<span class="special">,</span> <span class="keyword">typename</span> ElseIfThen<span class="special">></span>
44 <a class="link" href="call_if_statement.html" title="Struct template call_if_statement">call_if_statement</a><span class="special"><</span> <span class="keyword">true</span><span class="special">,</span> <span class="identifier">Then</span><span class="special">,</span> <span class="keyword">void</span> <span class="special">></span> <a class="link" href="call_if__idm45395000002720.html#idm45394999979296-bb"><span class="identifier">else_if</span></a><span class="special">(</span><span class="identifier">ElseIfThen</span> <span class="keyword">const</span> <span class="special">&</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
45 <span class="special">}</span><span class="special">;</span></pre></div>
46 <div class="refsect1">
47 <a name="idm45707997805664"></a><h2>Description</h2>
48 <p>Usually this class template is instantiated only via the return value of <code class="computeroutput"><a class="link" href="call_if.html" title="Function template call_if">boost::contract::call_if</a></code> and <code class="computeroutput"><a class="link" href="call_if_c.html" title="Function template call_if_c">boost::contract::call_if_c</a></code>.</p>
49 <p><span class="bold"><strong>See Also:</strong></span></p>
50 <p> <a class="link" href="../../boost_contract/extras.html#boost_contract.extras.assertion_requirements__templates_" title="Assertion Requirements (Templates)">
51 Assertion Requirements</a></p>
57 <div class="refsect2">
58 <a name="idm45707997800288"></a><h3>Template Parameters</h3>
59 <div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
60 <pre class="literallayout"><span class="keyword">typename</span> Then</pre>
61 <p>Type of functor template to call when the static predicate if <code class="computeroutput">true</code> (as it is for this template specialization). </p>
64 <div class="refsect2">
65 <a name="idm45707997796416"></a><h3>
66 <a name="boost.contract.call_if__idm45395000002720construct-copy-destruct"></a><code class="computeroutput">call_if_statement</code>
68 construct/copy/destruct</h3>
69 <div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
70 <pre class="literallayout"><span class="keyword">explicit</span> <a name="idm45394999971152-bb"></a><span class="identifier">call_if_statement</span><span class="special">(</span><span class="identifier">Then</span> f<span class="special">)</span><span class="special">;</span></pre>Construct this object with the then-branch functor template. <p>
72 <div class="variablelist"><table border="0" class="variablelist compact">
74 <col align="left" valign="top">
78 <td><p><span class="term">Parameters:</span></p></td>
79 <td><div class="variablelist"><table border="0" class="variablelist compact">
81 <col align="left" valign="top">
85 <td><p><span class="term"><code class="computeroutput">f</code></span></p></td>
86 <td><p>Then-branch nullary functor template. The functor template call <code class="computeroutput">f()</code> is actually compiled and executed for this template specialization (because the if-statement static predicate is <code class="computeroutput">true</code>). The return type of <code class="computeroutput">f()</code> must be <code class="computeroutput">void</code> for this template specialization (because the then-branch functor template calls return void). </p></td>
93 <div class="refsect2">
94 <a name="idm45707997782656"></a><h3>
95 <a name="idm45394999993936-bb"></a><code class="computeroutput">call_if_statement</code> public member functions</h3>
96 <div class="orderedlist"><ol class="orderedlist" type="1">
98 <pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Else<span class="special">></span> <span class="keyword">void</span> <a name="idm45394999993376-bb"></a><span class="identifier">else_</span><span class="special">(</span><span class="identifier">Else</span> <span class="keyword">const</span> <span class="special">&</span> f<span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>Specify the else-branch functor template. <p>
100 <div class="variablelist"><table border="0" class="variablelist compact">
102 <col align="left" valign="top">
106 <td><p><span class="term">Parameters:</span></p></td>
107 <td><div class="variablelist"><table border="0" class="variablelist compact">
109 <col align="left" valign="top">
113 <td><p><span class="term"><code class="computeroutput">f</code></span></p></td>
114 <td><p>Else-branch nullary functor template. The functor template call <code class="computeroutput">f()</code> is never compiled or executed for this template specialization (because the if-statement static predicate is <code class="computeroutput">true</code>). The return type of <code class="computeroutput">f()</code> must be <code class="computeroutput">void</code> for this template specialization (because the then-branch functor template calls return void). </p></td>
120 <li class="listitem">
121 <pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">bool</span> ElseIfPred<span class="special">,</span> <span class="keyword">typename</span> ElseIfThen<span class="special">></span>
122 <a class="link" href="call_if_statement.html" title="Struct template call_if_statement">call_if_statement</a><span class="special"><</span> <span class="keyword">true</span><span class="special">,</span> <span class="identifier">Then</span><span class="special">,</span> <span class="keyword">void</span> <span class="special">></span> <a name="idm45394999987552-bb"></a><span class="identifier">else_if_c</span><span class="special">(</span><span class="identifier">ElseIfThen</span> <span class="keyword">const</span> <span class="special">&</span> f<span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>Specify an else-if-branch functor template (using a static boolean predicate). <p>
126 <div class="variablelist"><table border="0" class="variablelist compact">
128 <col align="left" valign="top">
133 <td><p><span class="term">Parameters:</span></p></td>
134 <td><div class="variablelist"><table border="0" class="variablelist compact">
136 <col align="left" valign="top">
140 <td><p><span class="term"><code class="computeroutput">f</code></span></p></td>
141 <td><p>Else-if-branch nullary functor template. The functor template call <code class="computeroutput">f()</code> is never compiled or executed for this template specialization (because the if-statement static predicate is <code class="computeroutput">true</code>). The return type of <code class="computeroutput">f()</code> must be <code class="computeroutput">void</code> for this template specialization (because the then-branch functor template calls return void).</p></td>
146 <td><p><span class="term">Template Parameters:</span></p></td>
147 <td><div class="variablelist"><table border="0" class="variablelist compact">
149 <col align="left" valign="top">
153 <td><p><span class="term"><code class="computeroutput">ElseIfPred</code></span></p></td>
154 <td><p>Static boolean predicate selecting which functor template call to compile and execute.</p></td>
159 <td><p><span class="term">Returns:</span></p></td>
160 <td><p>A call-if statement so the else statement and additional else-if statements can be specified if needed. Eventually, it will return void for this template specialization (because the then-branch functor template calls return void). </p></td>
165 <li class="listitem">
166 <pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> ElseIfPred<span class="special">,</span> <span class="keyword">typename</span> ElseIfThen<span class="special">></span>
167 <a class="link" href="call_if_statement.html" title="Struct template call_if_statement">call_if_statement</a><span class="special"><</span> <span class="keyword">true</span><span class="special">,</span> <span class="identifier">Then</span><span class="special">,</span> <span class="keyword">void</span> <span class="special">></span> <a name="idm45394999979296-bb"></a><span class="identifier">else_if</span><span class="special">(</span><span class="identifier">ElseIfThen</span> <span class="keyword">const</span> <span class="special">&</span> f<span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>Specify an else-if-branch functor template (using a nullary boolean meta-function). <p>
171 <div class="variablelist"><table border="0" class="variablelist compact">
173 <col align="left" valign="top">
178 <td><p><span class="term">Parameters:</span></p></td>
179 <td><div class="variablelist"><table border="0" class="variablelist compact">
181 <col align="left" valign="top">
185 <td><p><span class="term"><code class="computeroutput">f</code></span></p></td>
186 <td><p>Else-if-branch nullary functor template. The functor template call <code class="computeroutput">f()</code> is never compiled or executed for this template specialization (because the if-statement static predicate is <code class="computeroutput">true</code>). The return type of <code class="computeroutput">f()</code> must be <code class="computeroutput">void</code> for this template specialization (because the then-branch functor template calls return void).</p></td>
191 <td><p><span class="term">Template Parameters:</span></p></td>
192 <td><div class="variablelist"><table border="0" class="variablelist compact">
194 <col align="left" valign="top">
198 <td><p><span class="term"><code class="computeroutput">ElseIfPred</code></span></p></td>
199 <td><p>Nullary boolean meta-function selecting which functor template call to compile and execute.</p></td>
204 <td><p><span class="term">Returns:</span></p></td>
205 <td><p>A call-if statement so the else statement and additional else-if statements can be specified if needed. Eventually, it will return void for this template specialization (because the then-branch functor template calls return void). </p></td>
214 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
215 <td align="left"></td>
216 <td align="right"><div class="copyright-footer">Copyright © 2008-2019 Lorenzo Caminiti<p>
217 Distributed under the Boost Software License, Version 1.0 (see accompanying
218 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>)
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