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<title>is_pointer</title>
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<div class="section boost_typetraits_reference_is_pointer">
<div class="titlepage"><div><div><h3 class="title">
<a name="boost_typetraits.reference.is_pointer"></a><a class="link" href="is_pointer.html" title="is_pointer">is_pointer</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_pointer</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> If T is a (possibly cv-qualified)
pointer type (includes function pointers, but excludes pointers to members)
then inherits from <a class="link" href="integral_constant.html" title="integral_constant">true_type</a>,
otherwise inherits from <a class="link" href="integral_constant.html" title="integral_constant">false_type</a>.
</p>
<p>
<span class="bold"><strong>C++ Standard Reference:</strong></span> 3.9.2p2 and 8.3.1.
</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_pointer</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>Examples:</strong></span>
</p>
<div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="identifier">is_pointer</span><span class="special"><</span><span class="keyword">int</span><span class="special">*></span></code>
inherits from <code class="computeroutput"><a class="link" href="integral_constant.html" title="integral_constant">true_type</a></code>.
</p></blockquote></div>
<div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="identifier">is_pointer</span><span class="special"><</span><span class="keyword">char</span><span class="special">*</span> <span class="keyword">const</span><span class="special">>::</span><span class="identifier">type</span></code>
is the type <code class="computeroutput"><a class="link" href="integral_constant.html" title="integral_constant">true_type</a></code>.
</p></blockquote></div>
<div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="identifier">is_pointer</span><span class="special"><</span><span class="keyword">int</span> <span class="special">(*)(</span><span class="keyword">long</span><span class="special">)>::</span><span class="identifier">value</span></code> is an integral constant expression
that evaluates to <span class="emphasis"><em>true</em></span>.
</p></blockquote></div>
<div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="identifier">is_pointer</span><span class="special"><</span><span class="keyword">int</span> <span class="special">(</span><span class="identifier">MyClass</span><span class="special">::*)(</span><span class="keyword">long</span><span class="special">)>::</span><span class="identifier">value</span></code>
is an integral constant expression that evaluates to <span class="emphasis"><em>false</em></span>.
</p></blockquote></div>
<div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="identifier">is_pointer</span><span class="special"><</span><span class="keyword">int</span> <span class="special">(</span><span class="identifier">MyClass</span><span class="special">::*)>::</span><span class="identifier">value</span></code>
is an integral constant expression that evaluates to <span class="emphasis"><em>false</em></span>.
</p></blockquote></div>
<div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="identifier">is_pointer</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">value_type</span></code> is the type <code class="computeroutput"><span class="keyword">bool</span></code>.
</p></blockquote></div>
<div class="important"><table border="0" summary="Important">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Important]" src="../../../../../../doc/src/images/important.png"></td>
<th align="left">Important</th>
</tr>
<tr><td align="left" valign="top"><p>
<code class="computeroutput"><span class="identifier">is_pointer</span></code> detects "real"
pointer types only, and <span class="emphasis"><em>not</em></span> smart pointers. Users
should not specialise <code class="computeroutput"><span class="identifier">is_pointer</span></code>
for smart pointer types, as doing so may cause Boost (and other third party)
code to fail to function correctly. Users wanting a trait to detect smart
pointers should create their own. However, note that there is no way in
general to auto-magically detect smart pointer types, so such a trait would
have to be partially specialised for each supported smart pointer type.
</p></td></tr>
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<td align="right"><div class="copyright-footer">Copyright © 2000, 2011 Adobe Systems Inc, David Abrahams,
Frederic Bron, Steve Cleary, Beman Dawes, Aleksey Gurtovoy, Howard Hinnant,
Jesse Jones, Mat Marcus, Itay Maman, John Maddock, Alexander Nasonov, Thorsten
Ottosen, Roman Perepelitsa, Robert Ramey, Jeremy Siek, Robert Stewart and Steven
Watanabe<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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