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| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="boost_typetraits.reference.is_stateless"></a><a class="link" href="is_stateless.html" title="is_stateless"> is_stateless</a> |
| </h3></div></div></div> |
| <pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> |
| <span class="keyword">struct</span> <span class="identifier">is_stateless</span> <span class="special">:</span> <span class="keyword">public</span> <em class="replaceable"><code><a class="link" href="integral_constant.html" title="integral_constant">true_type</a>-or-<a class="link" href="integral_constant.html" title="integral_constant">false_type</a></code></em> <span class="special">{};</span> |
| </pre> |
| <p> |
| <span class="bold"><strong>Inherits:</strong></span> Ff T is a stateless type then |
| inherits from <a class="link" href="integral_constant.html" title="integral_constant">true_type</a>, |
| otherwise from <a class="link" href="integral_constant.html" title="integral_constant">false_type</a>. |
| </p> |
| <p> |
| Type T must be a complete type. |
| </p> |
| <p> |
| A stateless type is a type that has no storage and whose constructors and |
| destructors are trivial. That means that <code class="computeroutput"><span class="identifier">is_stateless</span></code> |
| only inherits from <a class="link" href="integral_constant.html" title="integral_constant">true_type</a> |
| if the following expression is <code class="computeroutput"><span class="keyword">true</span></code>: |
| </p> |
| <pre class="programlisting"><span class="special">::</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">has_trivial_constructor</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">value</span> |
| <span class="special">&&</span> <span class="special">::</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">has_trivial_copy</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">value</span> |
| <span class="special">&&</span> <span class="special">::</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">has_trivial_destructor</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">value</span> |
| <span class="special">&&</span> <span class="special">::</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">is_class</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">value</span> |
| <span class="special">&&</span> <span class="special">::</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">is_empty</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">value</span> |
| </pre> |
| <p> |
| <span class="bold"><strong>C++ Standard Reference:</strong></span> 3.9p10. |
| </p> |
| <p> |
| <span class="bold"><strong>Header:</strong></span> <code class="computeroutput"> <span class="preprocessor">#include</span> |
| <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">type_traits</span><span class="special">/</span><span class="identifier">is_stateless</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> |
| or <code class="computeroutput"> <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">type_traits</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> |
| </p> |
| <p> |
| <span class="bold"><strong>Compiler Compatibility:</strong></span> If the compiler |
| does not support partial-specialization of class templates, then this template |
| can not be used with function types. |
| </p> |
| <p> |
| Without some (as yet unspecified) help from the compiler, is_stateless will |
| never report that a class or struct is stateless; this is always safe, if |
| possibly sub-optimal. Currently (May 2005) only MWCW 9 and Visual C++ 8 have |
| the necessary compiler <a class="link" href="../intrinsics.html" title="Support for Compiler Intrinsics">intrinsics</a> |
| to make this template work automatically. |
| </p> |
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| <td align="right"><div class="copyright-footer">Copyright © 2000, 2006 Adobe Systems Inc, David Abrahams, |
| Steve Cleary, Beman Dawes, Aleksey Gurtovoy, Howard Hinnant, Jesse Jones, Mat |
| Marcus, Itay Maman, John Maddock, Alexander Nasonov, Thorsten Ottosen, Robert |
| Ramey and Jeremy Siek<p> |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or 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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