123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137 |
- <html>
- <head>
- <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
- <title>Categorizing a Type</title>
- <link rel="stylesheet" href="../../../../../../../doc/src/boostbook.css" type="text/css">
- <meta name="generator" content="DocBook XSL Stylesheets V1.79.1">
- <link rel="home" href="../../../index.html" title="Chapter 1. Boost.TypeTraits">
- <link rel="up" href="../value_traits.html" title="Type Traits that Describe the Properties of a Type">
- <link rel="prev" href="../value_traits.html" title="Type Traits that Describe the Properties of a Type">
- <link rel="next" href="properties.html" title="General Type Properties">
- </head>
- <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
- <table cellpadding="2" width="100%"><tr>
- <td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../boost.png"></td>
- <td align="center"><a href="../../../../../../../index.html">Home</a></td>
- <td align="center"><a href="../../../../../../../libs/libraries.htm">Libraries</a></td>
- <td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
- <td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
- <td align="center"><a href="../../../../../../../more/index.htm">More</a></td>
- </tr></table>
- <hr>
- <div class="spirit-nav">
- <a accesskey="p" href="../value_traits.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../value_traits.html"><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="properties.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a>
- </div>
- <div class="section">
- <div class="titlepage"><div><div><h4 class="title">
- <a name="boost_typetraits.category.value_traits.primary"></a><a class="link" href="primary.html" title="Categorizing a Type">Categorizing
- a Type</a>
- </h4></div></div></div>
- <p>
- These traits identify what "kind" of type some type <code class="computeroutput"><span class="identifier">T</span></code> is. These are split into two groups:
- primary traits which are all mutually exclusive, and composite traits that
- are compositions of one or more primary traits.
- </p>
- <p>
- For any given type, exactly one primary type trait will inherit from <a class="link" href="../../reference/integral_constant.html" title="integral_constant">true_type</a>,
- and all the others will inherit from <a class="link" href="../../reference/integral_constant.html" title="integral_constant">false_type</a>,
- in other words these traits are mutually exclusive.
- </p>
- <p>
- This means that <code class="computeroutput"><a class="link" href="../../reference/is_integral.html" title="is_integral">is_integral</a><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">value</span></code>
- and <code class="computeroutput"><a class="link" href="../../reference/is_floating_point.html" title="is_floating_point">is_floating_point</a><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">value</span></code>
- will only ever be true for built-in types; if you want to check for a user-defined
- class type that behaves "as if" it is an integral or floating
- point type, then use the <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">numeric_limits</span>
- <span class="keyword">template</span></code> instead.
- </p>
- <p>
- <span class="bold"><strong>Synopsis:</strong></span>
- </p>
- <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> <a class="link" href="../../reference/is_array.html" title="is_array">is_array</a><span class="special">;</span>
- <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> <a class="link" href="../../reference/is_class.html" title="is_class">is_class</a><span class="special">;</span>
- <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> <a class="link" href="../../reference/is_complex.html" title="is_complex">is_complex</a><span class="special">;</span>
- <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> <a class="link" href="../../reference/is_enum.html" title="is_enum">is_enum</a><span class="special">;</span>
- <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> <a class="link" href="../../reference/is_floating_point.html" title="is_floating_point">is_floating_point</a><span class="special">;</span>
- <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> <a class="link" href="../../reference/is_function.html" title="is_function">is_function</a><span class="special">;</span>
- <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> <a class="link" href="../../reference/is_integral.html" title="is_integral">is_integral</a><span class="special">;</span>
- <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> <a class="link" href="../../reference/is_member_function_pointer.html" title="is_member_function_pointer">is_member_function_pointer</a><span class="special">;</span>
- <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> <a class="link" href="../../reference/is_member_object_pointer.html" title="is_member_object_pointer">is_member_object_pointer</a><span class="special">;</span>
- <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> <a class="link" href="../../reference/is_pointer.html" title="is_pointer">is_pointer</a><span class="special">;</span>
- <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> <a class="link" href="../../reference/is_lvalue_reference.html" title="is_lvalue_reference">is_lvalue_reference</a><span class="special">;</span>
- <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> <a class="link" href="../../reference/is_rvalue_reference.html" title="is_rvalue_reference">is_rvalue_reference</a><span class="special">;</span>
- <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> <a class="link" href="../../reference/is_union.html" title="is_union">is_union</a><span class="special">;</span>
- <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> <a class="link" href="../../reference/is_void.html" title="is_void">is_void</a><span class="special">;</span>
- </pre>
- <p>
- The following traits are made up of the union of one or more type categorizations.
- A type may belong to more than one of these categories, in addition to
- one of the primary categories.
- </p>
- <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> <a class="link" href="../../reference/is_arithmetic.html" title="is_arithmetic">is_arithmetic</a><span class="special">;</span>
- <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> <a class="link" href="../../reference/is_compound.html" title="is_compound">is_compound</a><span class="special">;</span>
- <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> <a class="link" href="../../reference/is_fundamental.html" title="is_fundamental">is_fundamental</a><span class="special">;</span>
- <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> <a class="link" href="../../reference/is_member_pointer.html" title="is_member_pointer">is_member_pointer</a><span class="special">;</span>
- <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> <a class="link" href="../../reference/is_object.html" title="is_object">is_object</a><span class="special">;</span>
- <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> <a class="link" href="../../reference/is_reference.html" title="is_reference">is_reference</a><span class="special">;</span>
- <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> <a class="link" href="../../reference/is_scalar.html" title="is_scalar">is_scalar</a><span class="special">;</span>
- </pre>
- </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 © 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>)
- </p>
- </div></td>
- </tr></table>
- <hr>
- <div class="spirit-nav">
- <a accesskey="p" href="../value_traits.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../value_traits.html"><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="properties.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a>
- </div>
- </body>
- </html>
|