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| <a name="boost.logic.tribool"></a><div class="titlepage"></div> |
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| <h2><span class="refentrytitle">Class tribool</span></h2> |
| <p>boost::logic::tribool — A 3-state boolean type. </p> |
| </div> |
| <h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> |
| <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="../../tribool/reference.html#header.boost.logic.tribool_hpp" title="Header <boost/logic/tribool.hpp>">boost/logic/tribool.hpp</a>> |
| |
| </span> |
| <span class="keyword">class</span> <a class="link" href="tribool.html" title="Class tribool">tribool</a> <span class="special">{</span> |
| <span class="keyword">public</span><span class="special">:</span> |
| <span class="keyword">enum</span> <a class="link" href="tribool/value_t.html" title="Type value_t">value_t</a><span class="special">;</span> |
| <span class="comment">// <a class="link" href="tribool.html#boost.logic.triboolconstruct-copy-destruct">construct/copy/destruct</a></span> |
| <a class="link" href="tribool.html#id656384-bb"><span class="identifier">tribool</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span> |
| <a class="link" href="tribool.html#id1136503-bb"><span class="identifier">tribool</span></a><span class="special">(</span><span class="keyword">bool</span><span class="special">)</span><span class="special">;</span> |
| <a class="link" href="tribool.html#id673755-bb"><span class="identifier">tribool</span></a><span class="special">(</span><span class="identifier">indeterminate_keyword_t</span><span class="special">)</span><span class="special">;</span> |
| |
| <span class="comment">// <a class="link" href="tribool.html#id656361-bb">public member functions</a></span> |
| <a class="link" href="tribool.html#id656363-bb"><span class="keyword">operator</span> <span class="identifier">safe_bool</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> |
| <span class="keyword">enum</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">logic</span><span class="special">::</span><span class="identifier">tribool</span><span class="special">::</span><span class="identifier">value_t</span> value<span class="special">;</span> |
| <span class="special">}</span><span class="special">;</span></pre></div> |
| <div class="refsect1"> |
| <a name="id2754157"></a><h2>Description</h2> |
| <p>3-state boolean values are either true, false, or indeterminate. </p> |
| <div class="refsect2"> |
| <a name="id2754164"></a><h3> |
| <a name="boost.logic.triboolconstruct-copy-destruct"></a><code class="computeroutput">tribool</code> |
| public |
| construct/copy/destruct</h3> |
| <div class="orderedlist"><ol class="orderedlist" type="1"> |
| <li class="listitem"> |
| <pre class="literallayout"><a name="id656384-bb"></a><span class="identifier">tribool</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre> |
| <p>Construct a new 3-state boolean value with the value 'false'.</p> |
| <p> |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody><tr> |
| <td><p><span class="term">Throws:</span></p></td> |
| <td>Will not throw.</td> |
| </tr></tbody> |
| </table></div> |
| </li> |
| <li class="listitem"> |
| <pre class="literallayout"><a name="id1136503-bb"></a><span class="identifier">tribool</span><span class="special">(</span><span class="keyword">bool</span> value<span class="special">)</span><span class="special">;</span></pre> |
| <p>Construct a new 3-state boolean value with the given boolean value, which may be <code class="computeroutput">true</code> or <code class="computeroutput">false</code>.</p> |
| <p> |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody><tr> |
| <td><p><span class="term">Throws:</span></p></td> |
| <td>Will not throw.</td> |
| </tr></tbody> |
| </table></div> |
| </li> |
| <li class="listitem"> |
| <pre class="literallayout"><a name="id673755-bb"></a><span class="identifier">tribool</span><span class="special">(</span><span class="identifier">indeterminate_keyword_t</span><span class="special">)</span><span class="special">;</span></pre> |
| <p>Construct a new 3-state boolean value with an indeterminate value.</p> |
| <p> |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody><tr> |
| <td><p><span class="term">Throws:</span></p></td> |
| <td>Will not throw.</td> |
| </tr></tbody> |
| </table></div> |
| </li> |
| </ol></div> |
| </div> |
| <div class="refsect2"> |
| <a name="id2754347"></a><h3> |
| <a name="id656361-bb"></a><code class="computeroutput">tribool</code> public member functions</h3> |
| <div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"> |
| <pre class="literallayout"><a name="id656363-bb"></a><span class="keyword">operator</span> <span class="identifier">safe_bool</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre> |
| <p>Use a 3-state boolean in a boolean context. Will evaluate true in a boolean context only when the 3-state boolean is definitely true.</p> |
| <p> |
| |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term">Returns:</span></p></td> |
| <td><p>true if the 3-state boolean is true, false otherwise </p></td> |
| </tr> |
| <tr> |
| <td><p><span class="term">Throws:</span></p></td> |
| <td>Will not throw.</td> |
| </tr> |
| </tbody> |
| </table></div> |
| </li></ol></div> |
| </div> |
| </div> |
| </div> |
| <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> |
| <td align="left"></td> |
| <td align="right"><div class="copyright-footer">Copyright © 2002-2004 Douglas Gregor<p>Use, modification and distribution is subject to the Boost |
| Software License, Version 1.0. (See accompanying file |
| <code class="filename">LICENSE_1_0.txt</code> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)</p> |
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