ceph/src/boost/tools/auto_index/test/test1.gold

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  10 <chapter xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" id="boost_typetraits" rev:last-revision="$Date: 2008-11-28 12:41:45 +0000 (Fri, 28 Nov 2008) $">
  11   <chapterinfo><author>
  12       <firstname>various</firstname> <surname>authors</surname>
  13     </author><copyright>
  14       <year>2000</year> <year>2006</year> <holder>Adobe Systems Inc, David Abrahams,
  15       Steve Cleary, Beman Dawes, Aleksey Gurtovoy, Howard Hinnant, Jesse Jones, Mat
  16       Marcus, Itay Maman, John Maddock, Alexander Nasonov, Thorsten Ottosen, Robert
  17       Ramey and Jeremy Siek</holder>
  18     </copyright><legalnotice>
  19       <para>
  20         Distributed under the Boost Software License, Version 1.0. (See accompanying
  21         file LICENSE_1_0.txt or copy at <ulink url="http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</ulink>)
  22       </para>
  23     </legalnotice></chapterinfo>
  24   <title>Boost.TypeTraits</title>
  25   <para>
  26     A printer-friendly <ulink url="http://svn.boost.org/svn/boost/sandbox/pdf/type_traits/release/type_traits.pdf">PDF
  27     version of this manual is also available</ulink>.
  28   </para>
  29   <section id="boost_typetraits.intro"><indexterm type="test_index_1"><primary>type-traits</primary><secondary>Introduction</secondary></indexterm><indexterm><primary>Introduction</primary><secondary>type-traits</secondary></indexterm><indexterm type="test_index_1"><primary>type-traits</primary><secondary>Introduction</secondary></indexterm><indexterm><primary>Introduction</primary><secondary>type-traits</secondary></indexterm><indexterm type="test_index_1"><primary>type-traits</primary><secondary>Introduction</secondary></indexterm><indexterm><primary>Introduction</primary><secondary>type-traits</secondary></indexterm>
  30     <title><link linkend="boost_typetraits.intro"> Introduction</link></title>
  31     <para>
  32       The Boost type-traits library contains a set of very specific traits classes,
  33       each of which encapsulate a single trait from the C++ type system; for example,
  34       is a type a pointer or a reference type? Or does a type have a trivial constructor,
  35       or a const-qualifier?
  36     </para>
  37     <para>
  38       The type-traits classes share a unified design: each class inherits from a
  39       the type <link linkend="boost_typetraits.reference.integral_constant">true_type</link>
  40       if the type has the specified property and inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>
  41       otherwise.
  42     </para>
  43     <para>
  44       The type-traits library also contains a set of classes that perform a specific
  45       transformation on a type; for example, they can remove a top-level const or
  46       volatile qualifier from a type. Each class that performs a transformation defines
  47       a single typedef-member <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">type</phrase></computeroutput>
  48       that is the result of the transformation.
  49     </para>
  50   </section>
  51   <section id="boost_typetraits.background"><indexterm type="test_index_2"><primary>type-traits</primary><secondary>Background and Tutorial</secondary></indexterm><indexterm><primary>Background and Tutorial</primary><secondary>type-traits</secondary></indexterm><indexterm type="test_index_2"><primary>type-traits</primary><secondary>Background and Tutorial</secondary></indexterm><indexterm><primary>Background and Tutorial</primary><secondary>type-traits</secondary></indexterm><indexterm type="class_name"><primary>remove_extent</primary><secondary>Background and Tutorial</secondary></indexterm><indexterm><primary>Background and Tutorial</primary><secondary>remove_extent</secondary></indexterm><indexterm type="class_name"><primary>is_pointer</primary><secondary>Background and Tutorial</secondary></indexterm><indexterm><primary>Background and Tutorial</primary><secondary>is_pointer</secondary></indexterm><indexterm type="class_name"><primary>is_void</primary><secondary>Background and Tutorial</secondary></indexterm><indexterm><primary>Background and Tutorial</primary><secondary>is_void</secondary></indexterm><indexterm type="test_index_2"><primary>type-traits</primary><secondary>Background and Tutorial</secondary></indexterm><indexterm><primary>Background and Tutorial</primary><secondary>type-traits</secondary></indexterm><indexterm type="test_index_2"><primary>type-traits</primary><secondary>Background and Tutorial</secondary></indexterm><indexterm><primary>Background and Tutorial</primary><secondary>type-traits</secondary></indexterm><indexterm type="test_index_2"><primary>type-traits</primary><secondary>Background and Tutorial</secondary></indexterm><indexterm><primary>Background and Tutorial</primary><secondary>type-traits</secondary></indexterm>
  52     <title><link linkend="boost_typetraits.background"> Background and Tutorial</link></title>
  53     <para>
  54       The following is an updated version of the article "C++ Type traits"
  55       by John Maddock and Steve Cleary that appeared in the October 2000 issue of
  56       <ulink url="http://www.ddj.com">Dr Dobb's Journal</ulink>.
  57     </para>
  58     <para>
  59       Generic programming (writing code which works with any data type meeting a
  60       set of requirements) has become the method of choice for providing reusable
  61       code. However, there are times in generic programming when "generic"
  62       just isn't good enough - sometimes the differences between types are too large
  63       for an efficient generic implementation. This is when the traits technique
  64       becomes important - by encapsulating those properties that need to be considered
  65       on a type by type basis inside a traits class, we can minimize the amount of
  66       code that has to differ from one type to another, and maximize the amount of
  67       generic code.
  68     </para>
  69     <?dbfo keep-together="auto" ?>
  70     <para>
  71       <indexterm>
  72         <primary>Foo1</primary>
  73       </indexterm>
  74       Consider an example: when working with character strings, one common operation
  75       is to determine the length of a null terminated string. Clearly it's possible
  76       to write generic code that can do this, but it turns out that there are much
  77       more efficient methods available: for example, the C library functions <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">strlen</phrase></computeroutput> and <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">wcslen</phrase></computeroutput>
  78       are usually written in assembler, and with suitable hardware support can be
  79       considerably faster than a generic version written in C++. The authors of the
  80       C++ standard library realized this, and abstracted the properties of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">char</phrase></computeroutput> and <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">wchar_t</phrase></computeroutput>
  81       into the class <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">char_traits</phrase></computeroutput>.
  82       Generic code that works with character strings can simply use <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">char_traits</phrase><phrase role="special">&lt;&gt;::</phrase><phrase role="identifier">length</phrase></computeroutput> to determine the length of a null
  83       terminated string, safe in the knowledge that specializations of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">char_traits</phrase></computeroutput> will use the most appropriate
  84       method available to them.
  85     </para>
  86     <anchor id="boost_typetraits.background.type_traits"/>
  87     <bridgehead renderas="sect4">
  88       <link linkend="boost_typetraits.background.type_traits">Type Traits</link>
  89     </bridgehead>
  90     <para>
  91       Class <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">char_traits</phrase></computeroutput> is a classic
  92       example of a collection of type specific properties wrapped up in a single
  93       class - what Nathan Myers termed a <emphasis>baggage class</emphasis><link linkend="background.references">[1]</link>. In the Boost type-traits library,
  94       we<link linkend="background.references">[2]</link> have written a set of very
  95       specific traits classes, each of which encapsulate a single trait from the
  96       C++ type system; for example, is a type a pointer or a reference type? Or does
  97       a type have a trivial constructor, or a const-qualifier? The type-traits classes
  98       share a unified design: each class inherits from a the type <link linkend="boost_typetraits.reference.integral_constant">true_type</link>
  99       if the type has the specified property and inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>
 100       otherwise. As we will show, these classes can be used in generic programming
 101       to determine the properties of a given type and introduce optimizations that
 102       are appropriate for that case.
 103     </para>
 104     <para>
 105       The type-traits library also contains a set of classes that perform a specific
 106       transformation on a type; for example, they can remove a top-level const or
 107       volatile qualifier from a type. Each class that performs a transformation defines
 108       a single typedef-member <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">type</phrase></computeroutput>
 109       that is the result of the transformation. All of the type-traits classes are
 110       defined inside namespace <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">boost</phrase></computeroutput>;
 111       for brevity, namespace-qualification is omitted in most of the code samples
 112       given.
 113     </para>
 114     <anchor id="boost_typetraits.background.implementation"/>
 115     <bridgehead renderas="sect4">
 116       <link linkend="boost_typetraits.background.implementation">Implementation</link>
 117     </bridgehead>
 118     <para>
 119       There are far too many separate classes contained in the type-traits library
 120       to give a full implementation here - see the source code in the Boost library
 121       for the full details - however, most of the implementation is fairly repetitive
 122       anyway, so here we will just give you a flavor for how some of the classes
 123       are implemented. Beginning with possibly the simplest class in the library,
 124       <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_void</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase></computeroutput> inherits
 125       from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>
 126       only if <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput> is <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">void</phrase></computeroutput>.
 127     </para>
 128
 129 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">typename</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 130 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_void">is_void</link> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <link linkend="boost_typetraits.reference.integral_constant">false_type</link><phrase role="special">{};</phrase>
 131
 132 <phrase role="keyword">template</phrase> <phrase role="special">&lt;&gt;</phrase>
 133 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_void">is_void</link><phrase role="special">&lt;</phrase><phrase role="keyword">void</phrase><phrase role="special">&gt;</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <link linkend="boost_typetraits.reference.integral_constant">true_type</link><phrase role="special">{};</phrase>
 134 </programlisting>
 135     <para>
 136       Here we define a primary version of the template class <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.is_void">is_void</link></computeroutput>,
 137       and provide a full-specialization when <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>
 138       is <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">void</phrase></computeroutput>. While full specialization
 139       of a template class is an important technique, sometimes we need a solution
 140       that is halfway between a fully generic solution, and a full specialization.
 141       This is exactly the situation for which the standards committee defined partial
 142       template-class specialization. As an example, consider the class <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">is_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase></computeroutput>:
 143       here we needed a primary version that handles all the cases where T is not
 144       a pointer, and a partial specialization to handle all the cases where T is
 145       a pointer:
 146     </para>
 147
 148 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">typename</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 149 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_pointer">is_pointer</link> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <link linkend="boost_typetraits.reference.integral_constant">false_type</link><phrase role="special">{};</phrase>
 150
 151 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">typename</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 152 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_pointer">is_pointer</link><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">*&gt;</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <link linkend="boost_typetraits.reference.integral_constant">true_type</link><phrase role="special">{};</phrase>
 153 </programlisting>
 154     <para>
 155       The syntax for partial specialization is somewhat arcane and could easily occupy
 156       an article in its own right; like full specialization, in order to write a
 157       partial specialization for a class, you must first declare the primary template.
 158       The partial specialization contains an extra &lt;...&gt; after the class name
 159       that contains the partial specialization parameters; these define the types
 160       that will bind to that partial specialization rather than the default template.
 161       The rules for what can appear in a partial specialization are somewhat convoluted,
 162       but as a rule of thumb if you can legally write two function overloads of the
 163       form:
 164     </para>
 165
 166 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">void</phrase> <phrase role="identifier">foo</phrase><phrase role="special">(</phrase><phrase role="identifier">T</phrase><phrase role="special">);</phrase>
 167 <phrase role="keyword">void</phrase> <phrase role="identifier">foo</phrase><phrase role="special">(</phrase><phrase role="identifier">U</phrase><phrase role="special">);</phrase>
 168 </programlisting>
 169     <para>
 170       Then you can also write a partial specialization of the form:
 171     </para>
 172
 173 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">typename</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 174 <phrase role="keyword">class</phrase> <phrase role="identifier">c</phrase><phrase role="special">{</phrase> <phrase role="comment">/*details*/</phrase> <phrase role="special">};</phrase>
 175
 176 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">typename</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 177 <phrase role="keyword">class</phrase> <phrase role="identifier">c</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">U</phrase><phrase role="special">&gt;{</phrase> <phrase role="comment">/*details*/</phrase> <phrase role="special">};</phrase>
 178 </programlisting>
 179     <para>
 180       This rule is by no means foolproof, but it is reasonably simple to remember
 181       and close enough to the actual rule to be useful for everyday use.
 182     </para>
 183     <para>
 184       As a more complex example of partial specialization consider the class <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_extent</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase></computeroutput>. This
 185       class defines a single typedef-member <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">type</phrase></computeroutput>
 186       that is the same type as T but with any top-level array bounds removed; this
 187       is an example of a traits class that performs a transformation on a type:
 188     </para>
 189
 190 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">typename</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 191 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.remove_extent">remove_extent</link>
 192 <phrase role="special">{</phrase> <phrase role="keyword">typedef</phrase> <phrase role="identifier">T</phrase> <phrase role="identifier">type</phrase><phrase role="special">;</phrase> <phrase role="special">};</phrase>
 193
 194 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">typename</phrase> <phrase role="identifier">T</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">N</phrase><phrase role="special">&gt;</phrase>
 195 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.remove_extent">remove_extent</link><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">[</phrase><phrase role="identifier">N</phrase><phrase role="special">]&gt;</phrase>
 196 <phrase role="special">{</phrase> <phrase role="keyword">typedef</phrase> <phrase role="identifier">T</phrase> <phrase role="identifier">type</phrase><phrase role="special">;</phrase> <phrase role="special">};</phrase>
 197 </programlisting>
 198     <para>
 199       The aim of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.remove_extent">remove_extent</link></computeroutput>
 200       is this: imagine a generic algorithm that is passed an array type as a template
 201       parameter, <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.remove_extent">remove_extent</link></computeroutput>
 202       provides a means of determining the underlying type of the array. For example
 203       <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_extent</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">[</phrase><phrase role="number">4</phrase><phrase role="special">][</phrase><phrase role="number">5</phrase><phrase role="special">]&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> would evaluate to the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">[</phrase><phrase role="number">5</phrase><phrase role="special">]</phrase></computeroutput>. This example also shows that the number of
 204       template parameters in a partial specialization does not have to match the
 205       number in the default template. However, the number of parameters that appear
 206       after the class name do have to match the number and type of the parameters
 207       in the default template.
 208     </para>
 209     <anchor id="boost_typetraits.background.optimized_copy"/>
 210     <bridgehead renderas="sect4">
 211       <link linkend="boost_typetraits.background.optimized_copy">Optimized copy</link>
 212     </bridgehead>
 213     <para>
 214       As an example of how the type traits classes can be used, consider the standard
 215       library algorithm copy:
 216     </para>
 217
 218 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">typename</phrase> <phrase role="identifier">Iter1</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Iter2</phrase><phrase role="special">&gt;</phrase>
 219 <phrase role="identifier">Iter2</phrase> <phrase role="identifier">copy</phrase><phrase role="special">(</phrase><phrase role="identifier">Iter1</phrase> <phrase role="identifier">first</phrase><phrase role="special">,</phrase> <phrase role="identifier">Iter1</phrase> <phrase role="identifier">last</phrase><phrase role="special">,</phrase> <phrase role="identifier">Iter2</phrase> <phrase role="identifier">out</phrase><phrase role="special">);</phrase>
 220 </programlisting>
 221     <para>
 222       Obviously, there's no problem writing a generic version of copy that works
 223       for all iterator types <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">Iter1</phrase></computeroutput>
 224       and <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">Iter2</phrase></computeroutput>; however, there are
 225       some circumstances when the copy operation can best be performed by a call
 226       to <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">memcpy</phrase></computeroutput>. In order to implement
 227       copy in terms of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">memcpy</phrase></computeroutput> all
 228       of the following conditions need to be met:
 229     </para>
 230     <itemizedlist>
 231       <listitem>
 232         Both of the iterator types <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">Iter1</phrase></computeroutput>
 233         and <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">Iter2</phrase></computeroutput> must be pointers.
 234       </listitem>
 235       <listitem>
 236         Both <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">Iter1</phrase></computeroutput> and <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">Iter2</phrase></computeroutput> must point to the same type - excluding
 237         const and volatile-qualifiers.
 238       </listitem>
 239       <listitem>
 240         The type pointed to by <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">Iter1</phrase></computeroutput>
 241         must have a trivial assignment operator.
 242       </listitem>
 243     </itemizedlist>
 244     <para>
 245       By trivial assignment operator we mean that the type is either a scalar type<link linkend="background.references">[3]</link> or:
 246     </para>
 247     <itemizedlist>
 248       <listitem>
 249         The type has no user defined assignment operator.
 250       </listitem>
 251       <listitem>
 252         The type does not have any data members that are references.
 253       </listitem>
 254       <listitem>
 255         All base classes, and all data member objects must have trivial assignment
 256         operators.
 257       </listitem>
 258     </itemizedlist>
 259     <para>
 260       If all these conditions are met then a type can be copied using <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">memcpy</phrase></computeroutput> rather than using a compiler generated
 261       assignment operator. The type-traits library provides a class <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.has_trivial_assign">has_trivial_assign</link></computeroutput>,
 262       such that <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_assign</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is true only if T has a trivial assignment
 263       operator. This class "just works" for scalar types, but has to be
 264       explicitly specialised for class/struct types that also happen to have a trivial
 265       assignment operator. In other words if <link linkend="boost_typetraits.reference.has_trivial_assign">has_trivial_assign</link>
 266       gives the wrong answer, it will give the "safe" wrong answer - that
 267       trivial assignment is not allowable.
 268     </para>
 269     <para>
 270       The code for an optimized version of copy that uses <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">memcpy</phrase></computeroutput>
 271       where appropriate is given in <link linkend="boost_typetraits.examples.copy">the
 272       examples</link>. The code begins by defining a template function <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">do_copy</phrase></computeroutput> that performs a "slow but safe"
 273       copy. The last parameter passed to this function may be either a <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>
 274       or a <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">false_type</link></computeroutput>.
 275       Following that there is an overload of do<emphasis role="underline">copy that
 276       uses `memcpy`: this time the iterators are required to actually be pointers
 277       to the same type, and the final parameter must be a `</emphasis>_true_type<computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="special">.</phrase> <phrase role="identifier">Finally</phrase><phrase role="special">,</phrase> <phrase role="identifier">the</phrase> <phrase role="identifier">version</phrase>
 278       <phrase role="identifier">of</phrase> </computeroutput>copy<computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="identifier">calls</phrase>
 279       </computeroutput>do<emphasis role="underline">copy`, passing `</emphasis>_has_trivial_assign&lt;value_type&gt;()`
 280       as the final parameter: this will dispatch to the optimized version where appropriate,
 281       otherwise it will call the "slow but safe version".
 282     </para>
 283     <anchor id="boost_typetraits.background.was_it_worth_it_"/>
 284     <bridgehead renderas="sect4">
 285       <link linkend="boost_typetraits.background.was_it_worth_it_">Was it worth it?</link>
 286     </bridgehead>
 287     <para>
 288       It has often been repeated in these columns that "premature optimization
 289       is the root of all evil" <link linkend="background.references">[4]</link>.
 290       So the question must be asked: was our optimization premature? To put this
 291       in perspective the timings for our version of copy compared a conventional
 292       generic copy<link linkend="background.references">[5]</link> are shown in table
 293       1.
 294     </para>
 295     <para>
 296       Clearly the optimization makes a difference in this case; but, to be fair,
 297       the timings are loaded to exclude cache miss effects - without this accurate
 298       comparison between algorithms becomes difficult. However, perhaps we can add
 299       a couple of caveats to the premature optimization rule:
 300     </para>
 301     <itemizedlist>
 302       <listitem>
 303         If you use the right algorithm for the job in the first place then optimization
 304         will not be required; in some cases, memcpy is the right algorithm.
 305       </listitem>
 306       <listitem>
 307         If a component is going to be reused in many places by many people then optimizations
 308         may well be worthwhile where they would not be so for a single case - in
 309         other words, the likelihood that the optimization will be absolutely necessary
 310         somewhere, sometime is that much higher. Just as importantly the perceived
 311         value of the stock implementation will be higher: there is no point standardizing
 312         an algorithm if users reject it on the grounds that there are better, more
 313         heavily optimized versions available.
 314       </listitem>
 315     </itemizedlist>
 316     <table frame="all"> <title>Time taken to copy 1000 elements using `copy&lt;const
 317     T*, T*&gt;` (times in micro-seconds)</title>
 318     <tgroup cols="3">
 319       <thead>
 320         <row>
 321           <entry>
 322           <para>
 323             Version
 324           </para>
 325           </entry><entry>
 326           <para>
 327             T
 328           </para>
 329           </entry><entry>
 330           <para>
 331             Time
 332           </para>
 333           </entry>
 334         </row>
 335       </thead>
 336       <tbody>
 337         <row>
 338           <entry>
 339           <para>
 340             "Optimized" copy
 341           </para>
 342           </entry><entry>
 343           <para>
 344             char
 345           </para>
 346           </entry><entry>
 347           <para>
 348             0.99
 349           </para>
 350           </entry>
 351         </row>
 352         <row>
 353           <entry>
 354           <para>
 355             Conventional copy
 356           </para>
 357           </entry><entry>
 358           <para>
 359             char
 360           </para>
 361           </entry><entry>
 362           <para>
 363             8.07
 364           </para>
 365           </entry>
 366         </row>
 367         <row>
 368           <entry>
 369           <para>
 370             "Optimized" copy
 371           </para>
 372           </entry><entry>
 373           <para>
 374             int
 375           </para>
 376           </entry><entry>
 377           <para>
 378             2.52
 379           </para>
 380           </entry>
 381         </row>
 382         <row>
 383           <entry>
 384           <para>
 385             Conventional copy
 386           </para>
 387           </entry><entry>
 388           <para>
 389             int
 390           </para>
 391           </entry><entry>
 392           <para>
 393             8.02
 394           </para>
 395           </entry>
 396         </row>
 397       </tbody>
 398     </tgroup>
 399     </table> <anchor id="boost_typetraits.background.pair_of_references"/>
 400     <bridgehead renderas="sect4">
 401       <link linkend="boost_typetraits.background.pair_of_references">Pair of References</link>
 402     </bridgehead>
 403     <para>
 404       The optimized copy example shows how type traits may be used to perform optimization
 405       decisions at compile-time. Another important usage of type traits is to allow
 406       code to compile that otherwise would not do so unless excessive partial specialization
 407       is used. This is possible by delegating partial specialization to the type
 408       traits classes. Our example for this form of usage is a pair that can hold
 409       references <link linkend="background.references">[6]</link>.
 410     </para>
 411     <para>
 412       First, let us examine the definition of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">pair</phrase></computeroutput>, omitting
 413       the comparison operators, default constructor, and template copy constructor
 414       for simplicity:
 415     </para>
 416
 417 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">typename</phrase> <phrase role="identifier">T1</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">T2</phrase><phrase role="special">&gt;</phrase>
 418 <phrase role="keyword">struct</phrase> <phrase role="identifier">pair</phrase>
 419 <phrase role="special">{</phrase>
 420 <phrase role="keyword">typedef</phrase> <phrase role="identifier">T1</phrase> <phrase role="identifier">first_type</phrase><phrase role="special">;</phrase>
 421 <phrase role="keyword">typedef</phrase> <phrase role="identifier">T2</phrase> <phrase role="identifier">second_type</phrase><phrase role="special">;</phrase>
 422
 423 <phrase role="identifier">T1</phrase> <phrase role="identifier">first</phrase><phrase role="special">;</phrase>
 424 <phrase role="identifier">T2</phrase> <phrase role="identifier">second</phrase><phrase role="special">;</phrase>
 425
 426 <phrase role="identifier">pair</phrase><phrase role="special">(</phrase><phrase role="keyword">const</phrase> <phrase role="identifier">T1</phrase> <phrase role="special">&amp;</phrase> <phrase role="identifier">nfirst</phrase><phrase role="special">,</phrase> <phrase role="keyword">const</phrase> <phrase role="identifier">T2</phrase> <phrase role="special">&amp;</phrase> <phrase role="identifier">nsecond</phrase><phrase role="special">)</phrase>
 427 <phrase role="special">:</phrase><phrase role="identifier">first</phrase><phrase role="special">(</phrase><phrase role="identifier">nfirst</phrase><phrase role="special">),</phrase> <phrase role="identifier">second</phrase><phrase role="special">(</phrase><phrase role="identifier">nsecond</phrase><phrase role="special">)</phrase> <phrase role="special">{</phrase> <phrase role="special">}</phrase>
 428 <phrase role="special">};</phrase>
 429 </programlisting>
 430     <para>
 431       Now, this "pair" cannot hold references as it currently stands, because
 432       the constructor would require taking a reference to a reference, which is currently
 433       illegal <link linkend="background.references">[7]</link>. Let us consider what
 434       the constructor's parameters would have to be in order to allow "pair"
 435       to hold non-reference types, references, and constant references:
 436     </para>
 437     <table frame="all"> <title>Required Constructor Argument Types</title>
 438     <tgroup cols="2">
 439       <thead>
 440         <row>
 441           <entry>
 442           <para>
 443             Type of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T1</phrase></computeroutput>
 444           </para>
 445           </entry><entry>
 446           <para>
 447             Type of parameter to initializing constructor
 448           </para>
 449           </entry>
 450         </row>
 451       </thead>
 452       <tbody>
 453         <row>
 454           <entry>
 455           <para>
 456             T
 457           </para>
 458           </entry><entry>
 459           <para>
 460             const T &amp;
 461           </para>
 462           </entry>
 463         </row>
 464         <row>
 465           <entry>
 466           <para>
 467             T &amp;
 468           </para>
 469           </entry><entry>
 470           <para>
 471             T &amp;
 472           </para>
 473           </entry>
 474         </row>
 475         <row>
 476           <entry>
 477           <para>
 478             const T &amp;
 479           </para>
 480           </entry><entry>
 481           <para>
 482             const T &amp;
 483           </para>
 484           </entry>
 485         </row>
 486       </tbody>
 487     </tgroup>
 488     </table>
 489     <para>
 490       A little familiarity with the type traits classes allows us to construct a
 491       single mapping that allows us to determine the type of parameter from the type
 492       of the contained class. The type traits classes provide a transformation <link linkend="boost_typetraits.reference.add_reference">add_reference</link>, which
 493       adds a reference to its type, unless it is already a reference.
 494     </para>
 495     <table frame="all"> <title>Using add_reference to synthesize the correct constructor
 496     type</title>
 497     <tgroup cols="3">
 498       <thead>
 499         <row>
 500           <entry>
 501           <para>
 502             Type of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T1</phrase></computeroutput>
 503           </para>
 504           </entry><entry>
 505           <para>
 506             Type of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">const</phrase> <phrase role="identifier">T1</phrase></computeroutput>
 507           </para>
 508           </entry><entry>
 509           <para>
 510             Type of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_reference</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">const</phrase> <phrase role="identifier">T1</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
 511           </para>
 512           </entry>
 513         </row>
 514       </thead>
 515       <tbody>
 516         <row>
 517           <entry>
 518           <para>
 519             T
 520           </para>
 521           </entry><entry>
 522           <para>
 523             const T
 524           </para>
 525           </entry><entry>
 526           <para>
 527             const T &amp;
 528           </para>
 529           </entry>
 530         </row>
 531         <row>
 532           <entry>
 533           <para>
 534             T &amp;
 535           </para>
 536           </entry><entry>
 537           <para>
 538             T &amp; [8]
 539           </para>
 540           </entry><entry>
 541           <para>
 542             T &amp;
 543           </para>
 544           </entry>
 545         </row>
 546         <row>
 547           <entry>
 548           <para>
 549             const T &amp;
 550           </para>
 551           </entry><entry>
 552           <para>
 553             const T &amp;
 554           </para>
 555           </entry><entry>
 556           <para>
 557             const T &amp;
 558           </para>
 559           </entry>
 560         </row>
 561       </tbody>
 562     </tgroup>
 563     </table>
 564     <para>
 565       This allows us to build a primary template definition for <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">pair</phrase></computeroutput>
 566       that can contain non-reference types, reference types, and constant reference
 567       types:
 568     </para>
 569
 570 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">typename</phrase> <phrase role="identifier">T1</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">T2</phrase><phrase role="special">&gt;</phrase>
 571 <phrase role="keyword">struct</phrase> <phrase role="identifier">pair</phrase>
 572 <phrase role="special">{</phrase>
 573 <phrase role="keyword">typedef</phrase> <phrase role="identifier">T1</phrase> <phrase role="identifier">first_type</phrase><phrase role="special">;</phrase>
 574 <phrase role="keyword">typedef</phrase> <phrase role="identifier">T2</phrase> <phrase role="identifier">second_type</phrase><phrase role="special">;</phrase>
 575
 576 <phrase role="identifier">T1</phrase> <phrase role="identifier">first</phrase><phrase role="special">;</phrase>
 577 <phrase role="identifier">T2</phrase> <phrase role="identifier">second</phrase><phrase role="special">;</phrase>
 578
 579 <phrase role="identifier">pair</phrase><phrase role="special">(</phrase><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><link linkend="boost_typetraits.reference.add_reference">add_reference</link><phrase role="special">&lt;</phrase><phrase role="keyword">const</phrase> <phrase role="identifier">T1</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase> <phrase role="identifier">nfirst</phrase><phrase role="special">,</phrase>
 580       <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><link linkend="boost_typetraits.reference.add_reference">add_reference</link><phrase role="special">&lt;</phrase><phrase role="keyword">const</phrase> <phrase role="identifier">T2</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase> <phrase role="identifier">nsecond</phrase><phrase role="special">)</phrase>
 581 <phrase role="special">:</phrase><phrase role="identifier">first</phrase><phrase role="special">(</phrase><phrase role="identifier">nfirst</phrase><phrase role="special">),</phrase> <phrase role="identifier">second</phrase><phrase role="special">(</phrase><phrase role="identifier">nsecond</phrase><phrase role="special">)</phrase> <phrase role="special">{</phrase> <phrase role="special">}</phrase>
 582 <phrase role="special">};</phrase>
 583 </programlisting>
 584     <para>
 585       Add back in the standard comparison operators, default constructor, and template
 586       copy constructor (which are all the same), and you have a <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">pair</phrase></computeroutput> that
 587       can hold reference types!
 588     </para>
 589     <para>
 590       This same extension could have been done using partial template specialization
 591       of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">pair</phrase></computeroutput>, but to specialize
 592       <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">pair</phrase></computeroutput> in this way would require
 593       three partial specializations, plus the primary template. Type traits allows
 594       us to define a single primary template that adjusts itself auto-magically to
 595       any of these partial specializations, instead of a brute-force partial specialization
 596       approach. Using type traits in this fashion allows programmers to delegate
 597       partial specialization to the type traits classes, resulting in code that is
 598       easier to maintain and easier to understand.
 599     </para>
 600     <anchor id="boost_typetraits.background.conclusion"/>
 601     <bridgehead renderas="sect4">
 602       <link linkend="boost_typetraits.background.conclusion">Conclusion</link>
 603     </bridgehead>
 604     <para>
 605       We hope that in this article we have been able to give you some idea of what
 606       type-traits are all about. A more complete listing of the available classes
 607       are in the boost documentation, along with further examples using type traits.
 608       Templates have enabled C++ uses to take the advantage of the code reuse that
 609       generic programming brings; hopefully this article has shown that generic programming
 610       does not have to sink to the lowest common denominator, and that templates
 611       can be optimal as well as generic.
 612     </para>
 613     <anchor id="boost_typetraits.background.acknowledgements"/>
 614     <bridgehead renderas="sect4">
 615       <link linkend="boost_typetraits.background.acknowledgements">Acknowledgements</link>
 616     </bridgehead>
 617     <para>
 618       The authors would like to thank Beman Dawes and Howard Hinnant for their helpful
 619       comments when preparing this article.
 620     </para>
 621     <anchor id="background.references"/> <anchor id="boost_typetraits.background.references"/>
 622     <bridgehead renderas="sect4">
 623       <link linkend="boost_typetraits.background.references">References</link>
 624     </bridgehead>
 625     <orderedlist inheritnum="ignore" continuation="restarts">
 626       <listitem>
 627         Nathan C. Myers, C++ Report, June 1995.
 628       </listitem>
 629       <listitem>
 630         The type traits library is based upon contributions by Steve Cleary, Beman
 631         Dawes, Howard Hinnant and John Maddock: it can be found at www.boost.org.
 632       </listitem>
 633       <listitem>
 634         A scalar type is an arithmetic type (i.e. a built-in integer or floating
 635         point type), an enumeration type, a pointer, a pointer to member, or a const-
 636         or volatile-qualified version of one of these types.
 637       </listitem>
 638       <listitem>
 639         This quote is from Donald Knuth, ACM Computing Surveys, December 1974, pg
 640         268.
 641       </listitem>
 642       <listitem>
 643         The test code is available as part of the boost utility library (see algo_opt_examples.cpp),
 644         the code was compiled with gcc 2.95 with all optimisations turned on, tests
 645         were conducted on a 400MHz Pentium II machine running Microsoft Windows 98.
 646       </listitem>
 647       <listitem>
 648         John Maddock and Howard Hinnant have submitted a "compressed_pair"
 649         library to Boost, which uses a technique similar to the one described here
 650         to hold references. Their pair also uses type traits to determine if any
 651         of the types are empty, and will derive instead of contain to conserve space
 652         -- hence the name "compressed".
 653       </listitem>
 654       <listitem>
 655         This is actually an issue with the C++ Core Language Working Group (issue
 656         #106), submitted by Bjarne Stroustrup. The tentative resolution is to allow
 657         a "reference to a reference to T" to mean the same thing as a "reference
 658         to T", but only in template instantiation, in a method similar to multiple
 659         cv-qualifiers.
 660       </listitem>
 661       <listitem>
 662         For those of you who are wondering why this shouldn't be const-qualified,
 663         remember that references are always implicitly constant (for example, you
 664         can't re-assign a reference). Remember also that "const T &amp;"
 665         is something completely different. For this reason, cv-qualifiers on template
 666         type arguments that are references are ignored.
 667       </listitem>
 668     </orderedlist>
 669   </section>
 670   <section id="boost_typetraits.category">
 671     <title><link linkend="boost_typetraits.category"> Type Traits by Category</link></title>
 672     <section id="boost_typetraits.category.value_traits">
 673       <title><link linkend="boost_typetraits.category.value_traits"> Type Traits
 674       that Describe the Properties of a Type</link></title>
 675       <para>
 676         <indexterm>
 677           <primary>Foo2</primary>
 678           <secondary>Bar2</secondary>
 679         </indexterm>
 680         These traits are all <emphasis>value traits</emphasis>, which is to say the
 681         traits classes all inherit from <link linkend="boost_typetraits.reference.integral_constant">integral_constant</link>,
 682         and are used to access some numerical property of a type. Often this is a
 683         simple true or false Boolean value, but in a few cases may be some other
 684         integer value (for example when dealing with type alignments, or array bounds:
 685         see <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.alignment_of">alignment_of</link></computeroutput>,
 686         <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.rank">rank</link></computeroutput>
 687         and <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.extent">extent</link></computeroutput>).
 688       </para>
 689       <section id="boost_typetraits.category.value_traits.primary">
 690         <title><link linkend="boost_typetraits.category.value_traits.primary"> Categorizing
 691         a Type</link></title>
 692         <para>
 693           These traits identify what "kind" of type some type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput> is. These are split into two groups:
 694           primary traits which are all mutually exclusive, and composite traits that
 695           are compositions of one or more primary traits.
 696         </para>
 697         <para>
 698           For any given type, exactly one primary type trait will inherit from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
 699           and all the others will inherit from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>,
 700           in other words these traits are mutually exclusive.
 701         </para>
 702         <para>
 703           This means that <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.is_integral">is_integral</link><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
 704           and <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.is_floating_point">is_floating_point</link><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
 705           will only ever be true for built-in types; if you want to check for a user-defined
 706           class type that behaves "as if" it is an integral or floating
 707           point type, then use the <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">numeric_limits</phrase>
 708           <phrase role="keyword">template</phrase></computeroutput> instead.
 709         </para>
 710         <para>
 711           <emphasis role="bold">Synopsis:</emphasis>
 712         </para>
 713
 714 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 715 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_array">is_array</link><phrase role="special">;</phrase>
 716
 717 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 718 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_class">is_class</link><phrase role="special">;</phrase>
 719
 720 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 721 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_complex">is_complex</link><phrase role="special">;</phrase>
 722
 723 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 724 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_enum">is_enum</link><phrase role="special">;</phrase>
 725
 726 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 727 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_floating_point">is_floating_point</link><phrase role="special">;</phrase>
 728
 729 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 730 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_function">is_function</link><phrase role="special">;</phrase>
 731
 732 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 733 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_integral">is_integral</link><phrase role="special">;</phrase>
 734
 735 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 736 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_member_function_pointer">is_member_function_pointer</link><phrase role="special">;</phrase>
 737
 738 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 739 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_member_object_pointer">is_member_object_pointer</link><phrase role="special">;</phrase>
 740
 741 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 742 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_pointer">is_pointer</link><phrase role="special">;</phrase>
 743
 744 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 745 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_reference">is_reference</link><phrase role="special">;</phrase>
 746
 747 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 748 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_union">is_union</link><phrase role="special">;</phrase>
 749
 750 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 751 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_void">is_void</link><phrase role="special">;</phrase>
 752 </programlisting>
 753         <para>
 754           The following traits are made up of the union of one or more type categorizations.
 755           A type may belong to more than one of these categories, in addition to
 756           one of the primary categories.
 757         </para>
 758
 759 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 760 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_arithmetic">is_arithmetic</link><phrase role="special">;</phrase>
 761
 762 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 763 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_compound">is_compound</link><phrase role="special">;</phrase>
 764
 765 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 766 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_fundamental">is_fundamental</link><phrase role="special">;</phrase>
 767
 768 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 769 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_member_pointer">is_member_pointer</link><phrase role="special">;</phrase>
 770
 771 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 772 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_object">is_object</link><phrase role="special">;</phrase>
 773
 774 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 775 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_scalar">is_scalar</link><phrase role="special">;</phrase>
 776 </programlisting>
 777       </section>
 778       <section id="boost_typetraits.category.value_traits.properties">
 779         <title><link linkend="boost_typetraits.category.value_traits.properties">
 780         General Type Properties</link></title>
 781         <para>
 782           The following templates describe the general properties of a type.
 783         </para>
 784         <para>
 785           <emphasis role="bold">Synopsis:</emphasis>
 786         </para>
 787
 788 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 789 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.alignment_of">alignment_of</link><phrase role="special">;</phrase>
 790
 791 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 792 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.has_nothrow_assign">has_nothrow_assign</link><phrase role="special">;</phrase>
 793
 794 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 795 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.has_nothrow_constructor">has_nothrow_constructor</link><phrase role="special">;</phrase>
 796
 797 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 798 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.has_nothrow_constructor">has_nothrow_default_constructor</link><phrase role="special">;</phrase>
 799
 800 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 801 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.has_nothrow_copy">has_nothrow_copy</link><phrase role="special">;</phrase>
 802
 803 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 804 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.has_nothrow_copy">has_nothrow_copy_constructor</link><phrase role="special">;</phrase>
 805
 806 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 807 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.has_trivial_assign">has_trivial_assign</link><phrase role="special">;</phrase>
 808
 809 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 810 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.has_trivial_constructor">has_trivial_constructor</link><phrase role="special">;</phrase>
 811
 812 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 813 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.has_trivial_constructor">has_trivial_default_constructor</link><phrase role="special">;</phrase>
 814
 815 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 816 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.has_trivial_copy">has_trivial_copy</link><phrase role="special">;</phrase>
 817
 818 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 819 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.has_trivial_copy">has_trivial_copy_constructor</link><phrase role="special">;</phrase>
 820
 821 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 822 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.has_trivial_destructor">has_trivial_destructor</link><phrase role="special">;</phrase>
 823
 824 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 825 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.has_virtual_destructor">has_virtual_destructor</link><phrase role="special">;</phrase>
 826
 827 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 828 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_abstract">is_abstract</link><phrase role="special">;</phrase>
 829
 830 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 831 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_const">is_const</link><phrase role="special">;</phrase>
 832
 833 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 834 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_empty">is_empty</link><phrase role="special">;</phrase>
 835
 836 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 837 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_stateless">is_stateless</link><phrase role="special">;</phrase>
 838
 839 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 840 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_pod">is_pod</link><phrase role="special">;</phrase>
 841
 842 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 843 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_polymorphic">is_polymorphic</link><phrase role="special">;</phrase>
 844
 845 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 846 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_signed">is_signed</link><phrase role="special">;</phrase>
 847
 848 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 849 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_unsigned">is_unsigned</link><phrase role="special">;</phrase>
 850
 851 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 852 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_volatile">is_volatile</link><phrase role="special">;</phrase>
 853
 854 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">N</phrase> <phrase role="special">=</phrase> <phrase role="number">0</phrase><phrase role="special">&gt;</phrase>
 855 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.extent">extent</link><phrase role="special">;</phrase>
 856
 857 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 858 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.rank">rank</link><phrase role="special">;</phrase>
 859 </programlisting>
 860       </section>
 861       <section id="boost_typetraits.category.value_traits.relate">
 862         <title><link linkend="boost_typetraits.category.value_traits.relate"> Relationships
 863         Between Two Types</link></title>
 864         <para>
 865           These templates determine the whether there is a relationship between two
 866           types:
 867         </para>
 868         <para>
 869           <emphasis role="bold">Synopsis:</emphasis>
 870         </para>
 871
 872 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">Base</phrase><phrase role="special">,</phrase> <phrase role="keyword">class</phrase> <phrase role="identifier">Derived</phrase><phrase role="special">&gt;</phrase>
 873 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_base_of">is_base_of</link><phrase role="special">;</phrase>
 874
 875 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">From</phrase><phrase role="special">,</phrase> <phrase role="keyword">class</phrase> <phrase role="identifier">To</phrase><phrase role="special">&gt;</phrase>
 876 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_convertible">is_convertible</link><phrase role="special">;</phrase>
 877
 878 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">,</phrase> <phrase role="keyword">class</phrase> <phrase role="identifier">U</phrase><phrase role="special">&gt;</phrase>
 879 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_same">is_same</link><phrase role="special">;</phrase>
 880 </programlisting>
 881       </section>
 882     </section>
 883     <section id="boost_typetraits.category.transform"><indexterm type="macro_name"><primary>BOOST_BROKEN_COMPILER_TYPE_TRAITS_SPECIALIZATION</primary><secondary>Type Traits that Transform One Type to Another</secondary></indexterm><indexterm><primary>Type Traits that Transform One Type to Another</primary><secondary>BOOST_BROKEN_COMPILER_TYPE_TRAITS_SPECIALIZATION</secondary></indexterm><indexterm type="macro_name"><primary>BOOST_BROKEN_COMPILER_TYPE_TRAITS_SPECIALIZATION</primary><secondary>Type Traits that Transform One Type to Another</secondary></indexterm><indexterm><primary>Type Traits that Transform One Type to Another</primary><secondary>BOOST_BROKEN_COMPILER_TYPE_TRAITS_SPECIALIZATION</secondary></indexterm>
 884       <title><link linkend="boost_typetraits.category.transform"> Type Traits that
 885       Transform One Type to Another</link></title>
 886       <para>
 887         The following templates transform one type to another, based upon some well-defined
 888         rule. Each template has a single member called <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">type</phrase></computeroutput>
 889         that is the result of applying the transformation to the template argument
 890         <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>.
 891       </para>
 892       <para>
 893         <emphasis role="bold">Synopsis:</emphasis>
 894       </para>
 895
 896 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 897 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.add_const">add_const</link><phrase role="special">;</phrase>
 898
 899 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 900 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.add_cv">add_cv</link><phrase role="special">;</phrase>
 901
 902 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 903 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.add_pointer">add_pointer</link><phrase role="special">;</phrase>
 904
 905 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 906 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.add_reference">add_reference</link><phrase role="special">;</phrase>
 907
 908 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 909 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.add_volatile">add_volatile</link><phrase role="special">;</phrase>
 910
 911 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 912 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.decay">decay</link><phrase role="special">;</phrase>
 913
 914 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 915 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.floating_point_promotion">floating_point_promotion</link><phrase role="special">;</phrase>
 916
 917 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 918 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.integral_promotion">integral_promotion</link><phrase role="special">;</phrase>
 919
 920 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 921 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.make_signed">make_signed</link><phrase role="special">;</phrase>
 922
 923 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 924 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.make_unsigned">make_unsigned</link><phrase role="special">;</phrase>
 925
 926 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 927 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.promote">promote</link><phrase role="special">;</phrase>
 928
 929 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 930 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.remove_all_extents">remove_all_extents</link><phrase role="special">;</phrase>
 931
 932 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 933 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.remove_const">remove_const</link><phrase role="special">;</phrase>
 934
 935 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 936 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.remove_cv">remove_cv</link><phrase role="special">;</phrase>
 937
 938 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 939 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.remove_extent">remove_extent</link><phrase role="special">;</phrase>
 940
 941 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 942 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.remove_pointer">remove_pointer</link><phrase role="special">;</phrase>
 943
 944 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 945 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.remove_reference">remove_reference</link><phrase role="special">;</phrase>
 946
 947 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
 948 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.remove_volatile">remove_volatile</link><phrase role="special">;</phrase>
 949 </programlisting>
 950       <anchor id="boost_typetraits.category.transform.broken_compiler_workarounds_"/>
 951       <bridgehead renderas="sect4">
 952         <link linkend="boost_typetraits.category.transform.broken_compiler_workarounds_">Broken
 953         Compiler Workarounds:</link>
 954       </bridgehead>
 955       <para>
 956         For all of these templates support for partial specialization of class templates
 957         is required to correctly implement the transformation. On the other hand,
 958         practice shows that many of the templates from this category are very useful,
 959         and often essential for implementing some generic libraries. Lack of these
 960         templates is often one of the major limiting factors in porting those libraries
 961         to compilers that do not yet support this language feature. As some of these
 962         compilers are going to be around for a while, and at least one of them is
 963         very wide-spread, it was decided that the library should provide workarounds
 964         where possible.
 965       </para>
 966       <para>
 967         The basic idea behind the workaround is to manually define full specializations
 968         of all type transformation templates for all fundamental types, and all their
 969         1st and 2nd rank cv-[un]qualified derivative pointer types, and to provide
 970         a user-level macro that will define all the explicit specializations needed
 971         for any user-defined type T.
 972       </para>
 973       <para>
 974         The first part guarantees the successful compilation of something like this:
 975       </para>
 976
 977 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">BOOST_STATIC_ASSERT</phrase><phrase role="special">((</phrase><phrase role="identifier">is_same</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase><phrase role="special">,</phrase> <phrase role="identifier">remove_reference</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">type</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase><phrase role="special">));</phrase>
 978 <phrase role="identifier">BOOST_STATIC_ASSERT</phrase><phrase role="special">((</phrase><phrase role="identifier">is_same</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase> <phrase role="keyword">const</phrase><phrase role="special">,</phrase> <phrase role="identifier">remove_reference</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase> <phrase role="keyword">const</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">type</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase><phrase role="special">));</phrase>
 979 <phrase role="identifier">BOOST_STATIC_ASSERT</phrase><phrase role="special">((</phrase><phrase role="identifier">is_same</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase> <phrase role="keyword">volatile</phrase><phrase role="special">,</phrase> <phrase role="identifier">remove_reference</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase> <phrase role="keyword">volatile</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">type</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase><phrase role="special">));</phrase>
 980 <phrase role="identifier">BOOST_STATIC_ASSERT</phrase><phrase role="special">((</phrase><phrase role="identifier">is_same</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase> <phrase role="keyword">const</phrase> <phrase role="keyword">volatile</phrase><phrase role="special">,</phrase> <phrase role="identifier">remove_reference</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase> <phrase role="keyword">const</phrase> <phrase role="keyword">volatile</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">type</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase><phrase role="special">));</phrase>
 981 <phrase role="identifier">BOOST_STATIC_ASSERT</phrase><phrase role="special">((</phrase><phrase role="identifier">is_same</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase><phrase role="special">*,</phrase> <phrase role="identifier">remove_reference</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase><phrase role="special">*&amp;&gt;::</phrase><phrase role="identifier">type</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase><phrase role="special">));</phrase>
 982 <phrase role="identifier">BOOST_STATIC_ASSERT</phrase><phrase role="special">((</phrase><phrase role="identifier">is_same</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase> <phrase role="keyword">const</phrase><phrase role="special">*,</phrase> <phrase role="identifier">remove_reference</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase> <phrase role="keyword">const</phrase><phrase role="special">*&amp;&gt;::</phrase><phrase role="identifier">type</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase><phrase role="special">));</phrase>
 983 <phrase role="special">...</phrase>
 984 <phrase role="identifier">BOOST_STATIC_ASSERT</phrase><phrase role="special">((</phrase><phrase role="identifier">is_same</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase> <phrase role="keyword">const</phrase> <phrase role="keyword">volatile</phrase><phrase role="special">*</phrase> <phrase role="keyword">const</phrase> <phrase role="keyword">volatile</phrase><phrase role="special">*</phrase> <phrase role="keyword">const</phrase> <phrase role="keyword">volatile</phrase><phrase role="special">,</phrase> <phrase role="identifier">remove_reference</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase> <phrase role="keyword">const</phrase> <phrase role="keyword">volatile</phrase><phrase role="special">*</phrase> <phrase role="keyword">const</phrase> <phrase role="keyword">volatile</phrase><phrase role="special">*</phrase> <phrase role="keyword">const</phrase> <phrase role="keyword">volatile</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">type</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase><phrase role="special">));</phrase>
 985 </programlisting>
 986       <para>
 987         and the second part provides the library's users with a mechanism to make
 988         the above code work not only for <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">char</phrase></computeroutput>,
 989         <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase></computeroutput> or other built-in type,
 990         but for their own types as well:
 991       </para>
 992
 993 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">namespace</phrase> <phrase role="identifier">myspace</phrase><phrase role="special">{</phrase>
 994    <phrase role="keyword">struct</phrase> <phrase role="identifier">MyClass</phrase> <phrase role="special">{};</phrase>
 995 <phrase role="special">}</phrase>
 996 <phrase role="comment">// declare this at global scope:
 997 </phrase><phrase role="identifier">BOOST_BROKEN_COMPILER_TYPE_TRAITS_SPECIALIZATION</phrase><phrase role="special">(</phrase><phrase role="identifier">myspace</phrase><phrase role="special">::</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">)</phrase>
 998 <phrase role="comment">// transformations on myspace::MyClass now work:
 999 </phrase><phrase role="identifier">BOOST_STATIC_ASSERT</phrase><phrase role="special">((</phrase><phrase role="identifier">is_same</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">myspace</phrase><phrase role="special">::</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">,</phrase> <phrase role="identifier">remove_reference</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">myspace</phrase><phrase role="special">::</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">type</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase><phrase role="special">));</phrase>
1000 <phrase role="identifier">BOOST_STATIC_ASSERT</phrase><phrase role="special">((</phrase><phrase role="identifier">is_same</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">myspace</phrase><phrase role="special">::</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">,</phrase> <phrase role="identifier">remove_const</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">myspace</phrase><phrase role="special">::</phrase><phrase role="identifier">MyClass</phrase> <phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase><phrase role="special">));</phrase>
1001 <phrase role="comment">// etc.
1002 </phrase></programlisting>
1003       <para>
1004         Note that the macro BOOST_BROKEN_COMPILER_TYPE_TRAITS_SPECIALIZATION evaluates
1005         to nothing on those compilers that <emphasis role="bold">do</emphasis> support
1006         partial specialization.
1007       </para>
1008     </section>
1009     <section id="boost_typetraits.category.alignment">
1010       <title><link linkend="boost_typetraits.category.alignment"> Synthesizing Types
1011       with Specific Alignments</link></title>
1012       <para>
1013         Some low level memory management routines need to synthesize a POD type with
1014         specific alignment properties. The template <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.type_with_alignment">type_with_alignment</link></computeroutput>
1015         finds the smallest type with a specified alignment, while template <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.aligned_storage">aligned_storage</link></computeroutput>
1016         creates a type with a specific size and alignment.
1017       </para>
1018       <para>
1019         <emphasis role="bold">Synopsis</emphasis>
1020       </para>
1021
1022 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">Align</phrase><phrase role="special">&gt;</phrase>
1023 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.type_with_alignment">type_with_alignment</link><phrase role="special">;</phrase>
1024
1025 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">Size</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">Align</phrase><phrase role="special">&gt;</phrase>
1026 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.aligned_storage">aligned_storage</link><phrase role="special">;</phrase>
1027 </programlisting>
1028     </section>
1029     <section id="boost_typetraits.category.function">
1030       <title><link linkend="boost_typetraits.category.function"> Decomposing Function
1031       Types</link></title>
1032       <para>
1033         The class template <link linkend="boost_typetraits.reference.function_traits">function_traits</link>
1034         extracts information from function types (see also <link linkend="boost_typetraits.reference.is_function">is_function</link>).
1035         This traits class allows you to tell how many arguments a function takes,
1036         what those argument types are, and what the return type is.
1037       </para>
1038       <para>
1039         <emphasis role="bold">Synopsis</emphasis>
1040       </para>
1041
1042 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">Align</phrase><phrase role="special">&gt;</phrase>
1043 <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.function_traits">function_traits</link><phrase role="special">;</phrase>
1044 </programlisting>
1045     </section>
1046   </section>
1047   <section id="boost_typetraits.user_defined"><indexterm type="class_name"><primary>is_union</primary><secondary>User Defined Specializations</secondary></indexterm><indexterm><primary>User Defined Specializations</primary><secondary>is_union</secondary></indexterm><indexterm type="class_name"><primary>is_class</primary><secondary>User Defined Specializations</secondary></indexterm><indexterm><primary>User Defined Specializations</primary><secondary>is_class</secondary></indexterm>
1048     <title><link linkend="boost_typetraits.user_defined"> User Defined Specializations</link></title>
1049     <para>
1050       Occationally the end user may need to provide their own specialization for
1051       one of the type traits - typically where intrinsic compiler support is required
1052       to implement a specific trait fully. These specializations should derive from
1053       boost::<link linkend="boost_typetraits.reference.integral_constant">true_type</link>
1054       or boost::<link linkend="boost_typetraits.reference.integral_constant">false_type</link>
1055       as appropriate:
1056     </para>
1057
1058 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_pod</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase>
1059 <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_class</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase>
1060 <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_union</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase>
1061
1062 <phrase role="keyword">struct</phrase> <phrase role="identifier">my_pod</phrase><phrase role="special">{};</phrase>
1063 <phrase role="keyword">struct</phrase> <phrase role="identifier">my_union</phrase>
1064 <phrase role="special">{</phrase>
1065    <phrase role="keyword">char</phrase> <phrase role="identifier">c</phrase><phrase role="special">;</phrase>
1066    <phrase role="keyword">int</phrase> <phrase role="identifier">i</phrase><phrase role="special">;</phrase>
1067 <phrase role="special">};</phrase>
1068
1069 <phrase role="keyword">namespace</phrase> <phrase role="identifier">boost</phrase>
1070 <phrase role="special">{</phrase>
1071    <phrase role="keyword">template</phrase><phrase role="special">&lt;&gt;</phrase>
1072    <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_pod">is_pod</link><phrase role="special">&lt;</phrase><phrase role="identifier">my_pod</phrase><phrase role="special">&gt;</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <link linkend="boost_typetraits.reference.integral_constant">true_type</link><phrase role="special">{};</phrase>
1073
1074    <phrase role="keyword">template</phrase><phrase role="special">&lt;&gt;</phrase>
1075    <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_pod">is_pod</link><phrase role="special">&lt;</phrase><phrase role="identifier">my_union</phrase><phrase role="special">&gt;</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <link linkend="boost_typetraits.reference.integral_constant">true_type</link><phrase role="special">{};</phrase>
1076
1077    <phrase role="keyword">template</phrase><phrase role="special">&lt;&gt;</phrase>
1078    <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_union">is_union</link><phrase role="special">&lt;</phrase><phrase role="identifier">my_union</phrase><phrase role="special">&gt;</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <link linkend="boost_typetraits.reference.integral_constant">true_type</link><phrase role="special">{};</phrase>
1079
1080    <phrase role="keyword">template</phrase><phrase role="special">&lt;&gt;</phrase>
1081    <phrase role="keyword">struct</phrase> <link linkend="boost_typetraits.reference.is_class">is_class</link><phrase role="special">&lt;</phrase><phrase role="identifier">my_union</phrase><phrase role="special">&gt;</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <link linkend="boost_typetraits.reference.integral_constant">false_type</link><phrase role="special">{};</phrase>
1082 <phrase role="special">}</phrase>
1083 </programlisting>
1084   </section>
1085   <section id="boost_typetraits.intrinsics"><indexterm type="macro_name"><primary>BOOST_IS_UNION</primary><secondary>Support for Compiler Intrinsics</secondary></indexterm><indexterm><primary>Support for Compiler Intrinsics</primary><secondary>BOOST_IS_UNION</secondary></indexterm><indexterm type="macro_name"><primary>BOOST_IS_POLYMORPHIC</primary><secondary>Support for Compiler Intrinsics</secondary></indexterm><indexterm><primary>Support for Compiler Intrinsics</primary><secondary>BOOST_IS_POLYMORPHIC</secondary></indexterm><indexterm type="macro_name"><primary>BOOST_IS_POD</primary><secondary>Support for Compiler Intrinsics</secondary></indexterm><indexterm><primary>Support for Compiler Intrinsics</primary><secondary>BOOST_IS_POD</secondary></indexterm><indexterm type="macro_name"><primary>BOOST_IS_ENUM</primary><secondary>Support for Compiler Intrinsics</secondary></indexterm><indexterm><primary>Support for Compiler Intrinsics</primary><secondary>BOOST_IS_ENUM</secondary></indexterm><indexterm type="macro_name"><primary>BOOST_IS_EMPTY</primary><secondary>Support for Compiler Intrinsics</secondary></indexterm><indexterm><primary>Support for Compiler Intrinsics</primary><secondary>BOOST_IS_EMPTY</secondary></indexterm><indexterm type="macro_name"><primary>BOOST_IS_CONVERTIBLE</primary><secondary>Support for Compiler Intrinsics</secondary></indexterm><indexterm><primary>Support for Compiler Intrinsics</primary><secondary>BOOST_IS_CONVERTIBLE</secondary></indexterm><indexterm type="macro_name"><primary>BOOST_IS_CLASS</primary><secondary>Support for Compiler Intrinsics</secondary></indexterm><indexterm><primary>Support for Compiler Intrinsics</primary><secondary>BOOST_IS_CLASS</secondary></indexterm><indexterm type="macro_name"><primary>BOOST_IS_BASE_OF</primary><secondary>Support for Compiler Intrinsics</secondary></indexterm><indexterm><primary>Support for Compiler Intrinsics</primary><secondary>BOOST_IS_BASE_OF</secondary></indexterm><indexterm type="macro_name"><primary>BOOST_IS_ABSTRACT</primary><secondary>Support for Compiler Intrinsics</secondary></indexterm><indexterm><primary>Support for Compiler Intrinsics</primary><secondary>BOOST_IS_ABSTRACT</secondary></indexterm><indexterm type="macro_name"><primary>BOOST_HAS_VIRTUAL_DESTRUCTOR</primary><secondary>Support for Compiler Intrinsics</secondary></indexterm><indexterm><primary>Support for Compiler Intrinsics</primary><secondary>BOOST_HAS_VIRTUAL_DESTRUCTOR</secondary></indexterm><indexterm type="macro_name"><primary>BOOST_HAS_TRIVIAL_DESTRUCTOR</primary><secondary>Support for Compiler Intrinsics</secondary></indexterm><indexterm><primary>Support for Compiler Intrinsics</primary><secondary>BOOST_HAS_TRIVIAL_DESTRUCTOR</secondary></indexterm><indexterm type="macro_name"><primary>BOOST_HAS_TRIVIAL_COPY</primary><secondary>Support for Compiler Intrinsics</secondary></indexterm><indexterm><primary>Support for Compiler Intrinsics</primary><secondary>BOOST_HAS_TRIVIAL_COPY</secondary></indexterm><indexterm type="macro_name"><primary>BOOST_HAS_TRIVIAL_CONSTRUCTOR</primary><secondary>Support for Compiler Intrinsics</secondary></indexterm><indexterm><primary>Support for Compiler Intrinsics</primary><secondary>BOOST_HAS_TRIVIAL_CONSTRUCTOR</secondary></indexterm><indexterm type="macro_name"><primary>BOOST_HAS_TRIVIAL_ASSIGN</primary><secondary>Support for Compiler Intrinsics</secondary></indexterm><indexterm><primary>Support for Compiler Intrinsics</primary><secondary>BOOST_HAS_TRIVIAL_ASSIGN</secondary></indexterm><indexterm type="macro_name"><primary>BOOST_HAS_NOTHROW_COPY</primary><secondary>Support for Compiler Intrinsics</secondary></indexterm><indexterm><primary>Support for Compiler Intrinsics</primary><secondary>BOOST_HAS_NOTHROW_COPY</secondary></indexterm><indexterm type="macro_name"><primary>BOOST_HAS_NOTHROW_CONSTRUCTOR</primary><secondary>Support for Compiler Intrinsics</secondary></indexterm><indexterm><primary>Support for Compiler Intrinsics</primary><secondary>BOOST_HAS_NOTHROW_CONSTRUCTOR</secondary></indexterm><indexterm type="macro_name"><primary>BOOST_HAS_NOTHROW_ASSIGN</primary><secondary>Support for Compiler Intrinsics</secondary></indexterm><indexterm><primary>Support for Compiler Intrinsics</primary><secondary>BOOST_HAS_NOTHROW_ASSIGN</secondary></indexterm><indexterm type="macro_name"><primary>BOOST_ALIGNMENT_OF</primary><secondary>Support for Compiler Intrinsics</secondary></indexterm><indexterm><primary>Support for Compiler Intrinsics</primary><secondary>BOOST_ALIGNMENT_OF</secondary></indexterm>
1086     <title><link linkend="boost_typetraits.intrinsics"> Support for Compiler Intrinsics</link></title>
1087     <para>
1088       There are some traits that can not be implemented within the current C++ language:
1089       to make these traits "just work" with user defined types, some kind
1090       of additional help from the compiler is required. Currently (April 2008) Visual
1091       C++ 8 and 9, GNU GCC 4.3 and MWCW 9 provide the necessary intrinsics, and other
1092       compilers will no doubt follow in due course.
1093     </para>
1094     <para>
1095       The Following traits classes always need compiler support to do the right thing
1096       for all types (but all have safe fallback positions if this support is unavailable):
1097     </para>
1098     <itemizedlist>
1099       <listitem>
1100         <link linkend="boost_typetraits.reference.is_union">is_union</link>
1101       </listitem>
1102       <listitem>
1103         <link linkend="boost_typetraits.reference.is_pod">is_pod</link>
1104       </listitem>
1105       <listitem>
1106         <link linkend="boost_typetraits.reference.has_trivial_constructor">has_trivial_constructor</link>
1107       </listitem>
1108       <listitem>
1109         <link linkend="boost_typetraits.reference.has_trivial_copy">has_trivial_copy</link>
1110       </listitem>
1111       <listitem>
1112         <link linkend="boost_typetraits.reference.has_trivial_assign">has_trivial_assign</link>
1113       </listitem>
1114       <listitem>
1115         <link linkend="boost_typetraits.reference.has_trivial_destructor">has_trivial_destructor</link>
1116       </listitem>
1117       <listitem>
1118         <link linkend="boost_typetraits.reference.has_nothrow_constructor">has_nothrow_constructor</link>
1119       </listitem>
1120       <listitem>
1121         <link linkend="boost_typetraits.reference.has_nothrow_copy">has_nothrow_copy</link>
1122       </listitem>
1123       <listitem>
1124         <link linkend="boost_typetraits.reference.has_nothrow_assign">has_nothrow_assign</link>
1125       </listitem>
1126       <listitem>
1127         <link linkend="boost_typetraits.reference.has_virtual_destructor">has_virtual_destructor</link>
1128       </listitem>
1129     </itemizedlist>
1130     <para>
1131       The following traits classes can't be portably implemented in the C++ language,
1132       although in practice, the implementations do in fact do the right thing on
1133       all the compilers we know about:
1134     </para>
1135     <itemizedlist>
1136       <listitem>
1137         <link linkend="boost_typetraits.reference.is_empty">is_empty</link>
1138       </listitem>
1139       <listitem>
1140         <link linkend="boost_typetraits.reference.is_polymorphic">is_polymorphic</link>
1141       </listitem>
1142     </itemizedlist>
1143     <para>
1144       The following traits classes are dependent on one or more of the above:
1145     </para>
1146     <itemizedlist>
1147       <listitem>
1148         <link linkend="boost_typetraits.reference.is_class">is_class</link>
1149       </listitem>
1150       <listitem>
1151         <link linkend="boost_typetraits.reference.is_stateless">is_stateless</link>
1152       </listitem>
1153     </itemizedlist>
1154     <para>
1155       The hooks for compiler-intrinsic support are defined in <ulink url="../../../../boost/type_traits/intrinsics.hpp">boost/type_traits/intrinsics.hpp</ulink>,
1156       adding support for new compilers is simply a matter of defining one of more
1157       of the following macros:
1158     </para>
1159     <table frame="all"> <title>Macros for Compiler Intrinsics</title>
1160     <tgroup cols="2">
1161       <thead>
1162         <row>
1163           <entry>
1164           <para>
1165             BOOST_IS_UNION(T)
1166           </para>
1167           </entry><entry>
1168           <para>
1169             Should evaluate to true if T is a union type
1170           </para>
1171           </entry>
1172         </row>
1173       </thead>
1174       <tbody>
1175         <row>
1176           <entry>
1177           <para>
1178             BOOST_IS_POD(T)
1179           </para>
1180           </entry><entry>
1181           <para>
1182             Should evaluate to true if T is a POD type
1183           </para>
1184           </entry>
1185         </row>
1186         <row>
1187           <entry>
1188           <para>
1189             BOOST_IS_EMPTY(T)
1190           </para>
1191           </entry><entry>
1192           <para>
1193             Should evaluate to true if T is an empty struct or union
1194           </para>
1195           </entry>
1196         </row>
1197         <row>
1198           <entry>
1199           <para>
1200             BOOST_HAS_TRIVIAL_CONSTRUCTOR(T)
1201           </para>
1202           </entry><entry>
1203           <para>
1204             Should evaluate to true if the default constructor for T is trivial (i.e.
1205             has no effect)
1206           </para>
1207           </entry>
1208         </row>
1209         <row>
1210           <entry>
1211           <para>
1212             BOOST_HAS_TRIVIAL_COPY(T)
1213           </para>
1214           </entry><entry>
1215           <para>
1216             Should evaluate to true if T has a trivial copy constructor (and can
1217             therefore be replaced by a call to memcpy)
1218           </para>
1219           </entry>
1220         </row>
1221         <row>
1222           <entry>
1223           <para>
1224             BOOST_HAS_TRIVIAL_ASSIGN(T)
1225           </para>
1226           </entry><entry>
1227           <para>
1228             Should evaluate to true if T has a trivial assignment operator (and can
1229             therefore be replaced by a call to memcpy)
1230           </para>
1231           </entry>
1232         </row>
1233         <row>
1234           <entry>
1235           <para>
1236             BOOST_HAS_TRIVIAL_DESTRUCTOR(T)
1237           </para>
1238           </entry><entry>
1239           <para>
1240             Should evaluate to true if T has a trivial destructor (i.e. ~T() has
1241             no effect)
1242           </para>
1243           </entry>
1244         </row>
1245         <row>
1246           <entry>
1247           <para>
1248             BOOST_HAS_NOTHROW_CONSTRUCTOR(T)
1249           </para>
1250           </entry><entry>
1251           <para>
1252             Should evaluate to true if <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase>
1253             <phrase role="identifier">x</phrase><phrase role="special">;</phrase></computeroutput>
1254             can not throw
1255           </para>
1256           </entry>
1257         </row>
1258         <row>
1259           <entry>
1260           <para>
1261             BOOST_HAS_NOTHROW_COPY(T)
1262           </para>
1263           </entry><entry>
1264           <para>
1265             Should evaluate to true if <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase><phrase role="special">(</phrase><phrase role="identifier">t</phrase><phrase role="special">)</phrase></computeroutput> can not throw
1266           </para>
1267           </entry>
1268         </row>
1269         <row>
1270           <entry>
1271           <para>
1272             BOOST_HAS_NOTHROW_ASSIGN(T)
1273           </para>
1274           </entry><entry>
1275           <para>
1276             Should evaluate to true if <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase>
1277             <phrase role="identifier">t</phrase><phrase role="special">,</phrase>
1278             <phrase role="identifier">u</phrase><phrase role="special">;</phrase>
1279             <phrase role="identifier">t</phrase> <phrase role="special">=</phrase>
1280             <phrase role="identifier">u</phrase></computeroutput> can not throw
1281           </para>
1282           </entry>
1283         </row>
1284         <row>
1285           <entry>
1286           <para>
1287             BOOST_HAS_VIRTUAL_DESTRUCTOR(T)
1288           </para>
1289           </entry><entry>
1290           <para>
1291             Should evaluate to true T has a virtual destructor
1292           </para>
1293           </entry>
1294         </row>
1295         <row>
1296           <entry>
1297           <para>
1298             BOOST_IS_ABSTRACT(T)
1299           </para>
1300           </entry><entry>
1301           <para>
1302             Should evaluate to true if T is an abstract type
1303           </para>
1304           </entry>
1305         </row>
1306         <row>
1307           <entry>
1308           <para>
1309             BOOST_IS_BASE_OF(T,U)
1310           </para>
1311           </entry><entry>
1312           <para>
1313             Should evaluate to true if T is a base class of U
1314           </para>
1315           </entry>
1316         </row>
1317         <row>
1318           <entry>
1319           <para>
1320             BOOST_IS_CLASS(T)
1321           </para>
1322           </entry><entry>
1323           <para>
1324             Should evaluate to true if T is a class type
1325           </para>
1326           </entry>
1327         </row>
1328         <row>
1329           <entry>
1330           <para>
1331             BOOST_IS_CONVERTIBLE(T,U)
1332           </para>
1333           </entry><entry>
1334           <para>
1335             Should evaluate to true if T is convertible to U
1336           </para>
1337           </entry>
1338         </row>
1339         <row>
1340           <entry>
1341           <para>
1342             BOOST_IS_ENUM(T)
1343           </para>
1344           </entry><entry>
1345           <para>
1346             Should evaluate to true is T is an enum
1347           </para>
1348           </entry>
1349         </row>
1350         <row>
1351           <entry>
1352           <para>
1353             BOOST_IS_POLYMORPHIC(T)
1354           </para>
1355           </entry><entry>
1356           <para>
1357             Should evaluate to true if T is a polymorphic type
1358           </para>
1359           </entry>
1360         </row>
1361         <row>
1362           <entry>
1363           <para>
1364             BOOST_ALIGNMENT_OF(T)
1365           </para>
1366           </entry><entry>
1367           <para>
1368             Should evaluate to the alignment requirements of type T.
1369           </para>
1370           </entry>
1371         </row>
1372       </tbody>
1373     </tgroup>
1374     </table>
1375   </section>
1376   <section id="boost_typetraits.mpl">
1377     <title><link linkend="boost_typetraits.mpl"> MPL Interoperability</link></title>
1378     <para>
1379       All the value based traits in this library conform to MPL's requirements for
1380       an <ulink url="../../../../libs/mpl/doc/refmanual/integral-constant.html">Integral
1381       Constant type</ulink>: that includes a number of rather intrusive workarounds
1382       for broken compilers.
1383     </para>
1384     <para>
1385       Purely as an implementation detail, this means that <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>
1386       inherits from <ulink url="../../../../libs/mpl/doc/refmanual/bool.html"><computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">mpl</phrase><phrase role="special">::</phrase><phrase role="identifier">true_</phrase></computeroutput></ulink>,
1387       <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">false_type</link></computeroutput>
1388       inherits from <ulink url="../../../../libs/mpl/doc/refmanual/bool.html"><computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">mpl</phrase><phrase role="special">::</phrase><phrase role="identifier">false_</phrase></computeroutput></ulink>,
1389       and <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">integral_constant</link><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">,</phrase>
1390       <phrase role="identifier">v</phrase><phrase role="special">&gt;</phrase></computeroutput>
1391       inherits from <ulink url="../../../../libs/mpl/doc/refmanual/integral-c.html"><computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">mpl</phrase><phrase role="special">::</phrase><phrase role="identifier">integral_c</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">,</phrase><phrase role="identifier">v</phrase><phrase role="special">&gt;</phrase></computeroutput></ulink>
1392       (provided <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput> is not <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>)
1393     </para>
1394   </section>
1395   <section id="boost_typetraits.examples">
1396     <title><link linkend="boost_typetraits.examples"> Examples</link></title>
1397     <section id="boost_typetraits.examples.copy"><indexterm type="typedef_name"><primary>value_type</primary><secondary>An Optimized Version of std::copy</secondary></indexterm><indexterm><primary>Optimized Version of std::copy</primary><secondary>value_type</secondary></indexterm>
1398       <title><link linkend="boost_typetraits.examples.copy"> An Optimized Version
1399       of std::copy</link></title>
1400       <para>
1401         Demonstrates a version of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">copy</phrase></computeroutput>
1402         that uses <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.has_trivial_assign">has_trivial_assign</link></computeroutput>
1403         to determine whether to use <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">memcpy</phrase></computeroutput>
1404         to optimise the copy operation (see <ulink url="../../examples/copy_example.cpp">copy_example.cpp</ulink>):
1405       </para>
1406
1407 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="comment">//
1408 </phrase><phrase role="comment">// opt::copy
1409 </phrase><phrase role="comment">// same semantics as std::copy
1410 </phrase><phrase role="comment">// calls memcpy where appropriate.
1411 </phrase><phrase role="comment">//
1412 </phrase>
1413 <phrase role="keyword">namespace</phrase> <phrase role="identifier">detail</phrase><phrase role="special">{</phrase>
1414
1415 <phrase role="keyword">template</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">typename</phrase> <phrase role="identifier">I1</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">I2</phrase><phrase role="special">,</phrase> <phrase role="keyword">bool</phrase> <phrase role="identifier">b</phrase><phrase role="special">&gt;</phrase>
1416 <phrase role="identifier">I2</phrase> <phrase role="identifier">copy_imp</phrase><phrase role="special">(</phrase><phrase role="identifier">I1</phrase> <phrase role="identifier">first</phrase><phrase role="special">,</phrase> <phrase role="identifier">I1</phrase> <phrase role="identifier">last</phrase><phrase role="special">,</phrase> <phrase role="identifier">I2</phrase> <phrase role="identifier">out</phrase><phrase role="special">,</phrase> <phrase role="keyword">const</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><link linkend="boost_typetraits.reference.integral_constant">integral_constant</link><phrase role="special">&lt;</phrase><phrase role="keyword">bool</phrase><phrase role="special">,</phrase> <phrase role="identifier">b</phrase><phrase role="special">&gt;&amp;)</phrase>
1417 <phrase role="special">{</phrase>
1418    <phrase role="keyword">while</phrase><phrase role="special">(</phrase><phrase role="identifier">first</phrase> <phrase role="special">!=</phrase> <phrase role="identifier">last</phrase><phrase role="special">)</phrase>
1419    <phrase role="special">{</phrase>
1420       <phrase role="special">*</phrase><phrase role="identifier">out</phrase> <phrase role="special">=</phrase> <phrase role="special">*</phrase><phrase role="identifier">first</phrase><phrase role="special">;</phrase>
1421       <phrase role="special">++</phrase><phrase role="identifier">out</phrase><phrase role="special">;</phrase>
1422       <phrase role="special">++</phrase><phrase role="identifier">first</phrase><phrase role="special">;</phrase>
1423    <phrase role="special">}</phrase>
1424    <phrase role="keyword">return</phrase> <phrase role="identifier">out</phrase><phrase role="special">;</phrase>
1425 <phrase role="special">}</phrase>
1426
1427 <phrase role="keyword">template</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">typename</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
1428 <phrase role="identifier">T</phrase><phrase role="special">*</phrase> <phrase role="identifier">copy_imp</phrase><phrase role="special">(</phrase><phrase role="keyword">const</phrase> <phrase role="identifier">T</phrase><phrase role="special">*</phrase> <phrase role="identifier">first</phrase><phrase role="special">,</phrase> <phrase role="keyword">const</phrase> <phrase role="identifier">T</phrase><phrase role="special">*</phrase> <phrase role="identifier">last</phrase><phrase role="special">,</phrase> <phrase role="identifier">T</phrase><phrase role="special">*</phrase> <phrase role="identifier">out</phrase><phrase role="special">,</phrase> <phrase role="keyword">const</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><link linkend="boost_typetraits.reference.integral_constant">true_type</link><phrase role="special">&amp;)</phrase>
1429 <phrase role="special">{</phrase>
1430    <phrase role="identifier">memcpy</phrase><phrase role="special">(</phrase><phrase role="identifier">out</phrase><phrase role="special">,</phrase> <phrase role="identifier">first</phrase><phrase role="special">,</phrase> <phrase role="special">(</phrase><phrase role="identifier">last</phrase><phrase role="special">-</phrase><phrase role="identifier">first</phrase><phrase role="special">)*</phrase><phrase role="keyword">sizeof</phrase><phrase role="special">(</phrase><phrase role="identifier">T</phrase><phrase role="special">));</phrase>
1431    <phrase role="keyword">return</phrase> <phrase role="identifier">out</phrase><phrase role="special">+(</phrase><phrase role="identifier">last</phrase><phrase role="special">-</phrase><phrase role="identifier">first</phrase><phrase role="special">);</phrase>
1432 <phrase role="special">}</phrase>
1433
1434
1435 <phrase role="special">}</phrase>
1436
1437 <phrase role="keyword">template</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">typename</phrase> <phrase role="identifier">I1</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">I2</phrase><phrase role="special">&gt;</phrase>
1438 <phrase role="keyword">inline</phrase> <phrase role="identifier">I2</phrase> <phrase role="identifier">copy</phrase><phrase role="special">(</phrase><phrase role="identifier">I1</phrase> <phrase role="identifier">first</phrase><phrase role="special">,</phrase> <phrase role="identifier">I1</phrase> <phrase role="identifier">last</phrase><phrase role="special">,</phrase> <phrase role="identifier">I2</phrase> <phrase role="identifier">out</phrase><phrase role="special">)</phrase>
1439 <phrase role="special">{</phrase>
1440    <phrase role="comment">//
1441 </phrase>   <phrase role="comment">// We can copy with memcpy if T has a trivial assignment operator,
1442 </phrase>   <phrase role="comment">// and if the iterator arguments are actually pointers (this last
1443 </phrase>   <phrase role="comment">// requirement we detect with overload resolution):
1444 </phrase>   <phrase role="comment">//
1445 </phrase>   <phrase role="keyword">typedef</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">iterator_traits</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">I1</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase> <phrase role="identifier">value_type</phrase><phrase role="special">;</phrase>
1446    <phrase role="keyword">return</phrase> <phrase role="identifier">detail</phrase><phrase role="special">::</phrase><phrase role="identifier">copy_imp</phrase><phrase role="special">(</phrase><phrase role="identifier">first</phrase><phrase role="special">,</phrase> <phrase role="identifier">last</phrase><phrase role="special">,</phrase> <phrase role="identifier">out</phrase><phrase role="special">,</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><link linkend="boost_typetraits.reference.has_trivial_assign">has_trivial_assign</link><phrase role="special">&lt;</phrase><phrase role="identifier">value_type</phrase><phrase role="special">&gt;());</phrase>
1447 <phrase role="special">}</phrase>
1448 </programlisting>
1449     </section>
1450     <section id="boost_typetraits.examples.fill">
1451       <title><link linkend="boost_typetraits.examples.fill"> An Optimised Version
1452       of std::fill</link></title>
1453       <para>
1454         Demonstrates a version of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">fill</phrase></computeroutput>
1455         that uses <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.has_trivial_assign">has_trivial_assign</link></computeroutput>
1456         to determine whether to use <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">memset</phrase></computeroutput>
1457         to optimise the fill operation (see <ulink url="../../examples/fill_example.cpp">fill_example.cpp</ulink>):
1458       </para>
1459
1460 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="comment">//
1461 </phrase><phrase role="comment">// fill
1462 </phrase><phrase role="comment">// same as std::fill, but uses memset where appropriate
1463 </phrase><phrase role="comment">//
1464 </phrase><phrase role="keyword">namespace</phrase> <phrase role="identifier">detail</phrase><phrase role="special">{</phrase>
1465
1466 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">typename</phrase> <phrase role="identifier">I</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">T</phrase><phrase role="special">,</phrase> <phrase role="keyword">bool</phrase> <phrase role="identifier">b</phrase><phrase role="special">&gt;</phrase>
1467 <phrase role="keyword">void</phrase> <phrase role="identifier">do_fill</phrase><phrase role="special">(</phrase><phrase role="identifier">I</phrase> <phrase role="identifier">first</phrase><phrase role="special">,</phrase> <phrase role="identifier">I</phrase> <phrase role="identifier">last</phrase><phrase role="special">,</phrase> <phrase role="keyword">const</phrase> <phrase role="identifier">T</phrase><phrase role="special">&amp;</phrase> <phrase role="identifier">val</phrase><phrase role="special">,</phrase> <phrase role="keyword">const</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><link linkend="boost_typetraits.reference.integral_constant">integral_constant</link><phrase role="special">&lt;</phrase><phrase role="keyword">bool</phrase><phrase role="special">,</phrase> <phrase role="identifier">b</phrase><phrase role="special">&gt;&amp;)</phrase>
1468 <phrase role="special">{</phrase>
1469    <phrase role="keyword">while</phrase><phrase role="special">(</phrase><phrase role="identifier">first</phrase> <phrase role="special">!=</phrase> <phrase role="identifier">last</phrase><phrase role="special">)</phrase>
1470    <phrase role="special">{</phrase>
1471       <phrase role="special">*</phrase><phrase role="identifier">first</phrase> <phrase role="special">=</phrase> <phrase role="identifier">val</phrase><phrase role="special">;</phrase>
1472       <phrase role="special">++</phrase><phrase role="identifier">first</phrase><phrase role="special">;</phrase>
1473    <phrase role="special">}</phrase>
1474 <phrase role="special">}</phrase>
1475
1476 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">typename</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
1477 <phrase role="keyword">void</phrase> <phrase role="identifier">do_fill</phrase><phrase role="special">(</phrase><phrase role="identifier">T</phrase><phrase role="special">*</phrase> <phrase role="identifier">first</phrase><phrase role="special">,</phrase> <phrase role="identifier">T</phrase><phrase role="special">*</phrase> <phrase role="identifier">last</phrase><phrase role="special">,</phrase> <phrase role="keyword">const</phrase> <phrase role="identifier">T</phrase><phrase role="special">&amp;</phrase> <phrase role="identifier">val</phrase><phrase role="special">,</phrase> <phrase role="keyword">const</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><link linkend="boost_typetraits.reference.integral_constant">true_type</link><phrase role="special">&amp;)</phrase>
1478 <phrase role="special">{</phrase>
1479    <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">memset</phrase><phrase role="special">(</phrase><phrase role="identifier">first</phrase><phrase role="special">,</phrase> <phrase role="identifier">val</phrase><phrase role="special">,</phrase> <phrase role="identifier">last</phrase><phrase role="special">-</phrase><phrase role="identifier">first</phrase><phrase role="special">);</phrase>
1480 <phrase role="special">}</phrase>
1481
1482 <phrase role="special">}</phrase>
1483
1484 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">I</phrase><phrase role="special">,</phrase> <phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
1485 <phrase role="keyword">inline</phrase> <phrase role="keyword">void</phrase> <phrase role="identifier">fill</phrase><phrase role="special">(</phrase><phrase role="identifier">I</phrase> <phrase role="identifier">first</phrase><phrase role="special">,</phrase> <phrase role="identifier">I</phrase> <phrase role="identifier">last</phrase><phrase role="special">,</phrase> <phrase role="keyword">const</phrase> <phrase role="identifier">T</phrase><phrase role="special">&amp;</phrase> <phrase role="identifier">val</phrase><phrase role="special">)</phrase>
1486 <phrase role="special">{</phrase>
1487    <phrase role="comment">//
1488 </phrase>   <phrase role="comment">// We can do an optimised fill if T has a trivial assignment
1489 </phrase>   <phrase role="comment">// operator and if it's size is one:
1490 </phrase>   <phrase role="comment">//
1491 </phrase>   <phrase role="keyword">typedef</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><link linkend="boost_typetraits.reference.integral_constant">integral_constant</link><phrase role="special">&lt;</phrase><phrase role="keyword">bool</phrase><phrase role="special">,</phrase>
1492       <phrase role="special">::</phrase><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><link linkend="boost_typetraits.reference.has_trivial_assign">has_trivial_assign</link><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase> <phrase role="special">&amp;&amp;</phrase> <phrase role="special">(</phrase><phrase role="keyword">sizeof</phrase><phrase role="special">(</phrase><phrase role="identifier">T</phrase><phrase role="special">)</phrase> <phrase role="special">==</phrase> <phrase role="number">1</phrase><phrase role="special">)&gt;</phrase> <phrase role="identifier">truth_type</phrase><phrase role="special">;</phrase>
1493    <phrase role="identifier">detail</phrase><phrase role="special">::</phrase><phrase role="identifier">do_fill</phrase><phrase role="special">(</phrase><phrase role="identifier">first</phrase><phrase role="special">,</phrase> <phrase role="identifier">last</phrase><phrase role="special">,</phrase> <phrase role="identifier">val</phrase><phrase role="special">,</phrase> <phrase role="identifier">truth_type</phrase><phrase role="special">());</phrase>
1494 <phrase role="special">}</phrase>
1495 </programlisting>
1496     </section>
1497     <section id="boost_typetraits.examples.destruct">
1498       <title><link linkend="boost_typetraits.examples.destruct"> An Example that
1499       Omits Destructor Calls For Types with Trivial Destructors</link></title>
1500       <para>
1501         Demonstrates a simple algorithm that uses <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">__has_trivial_destruct</phrase></computeroutput>
1502         to determine whether to destructors need to be called (see <ulink url="../../examples/trivial_destructor_example.cpp">trivial_destructor_example.cpp</ulink>):
1503       </para>
1504
1505 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="comment">//
1506 </phrase><phrase role="comment">// algorithm destroy_array:
1507 </phrase><phrase role="comment">// The reverse of std::unitialized_copy, takes a block of
1508 </phrase><phrase role="comment">// initialized memory and calls destructors on all objects therein.
1509 </phrase><phrase role="comment">//
1510 </phrase>
1511 <phrase role="keyword">namespace</phrase> <phrase role="identifier">detail</phrase><phrase role="special">{</phrase>
1512
1513 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
1514 <phrase role="keyword">void</phrase> <phrase role="identifier">do_destroy_array</phrase><phrase role="special">(</phrase><phrase role="identifier">T</phrase><phrase role="special">*</phrase> <phrase role="identifier">first</phrase><phrase role="special">,</phrase> <phrase role="identifier">T</phrase><phrase role="special">*</phrase> <phrase role="identifier">last</phrase><phrase role="special">,</phrase> <phrase role="keyword">const</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><link linkend="boost_typetraits.reference.integral_constant">false_type</link><phrase role="special">&amp;)</phrase>
1515 <phrase role="special">{</phrase>
1516    <phrase role="keyword">while</phrase><phrase role="special">(</phrase><phrase role="identifier">first</phrase> <phrase role="special">!=</phrase> <phrase role="identifier">last</phrase><phrase role="special">)</phrase>
1517    <phrase role="special">{</phrase>
1518       <phrase role="identifier">first</phrase><phrase role="special">-&gt;~</phrase><phrase role="identifier">T</phrase><phrase role="special">();</phrase>
1519       <phrase role="special">++</phrase><phrase role="identifier">first</phrase><phrase role="special">;</phrase>
1520    <phrase role="special">}</phrase>
1521 <phrase role="special">}</phrase>
1522
1523 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
1524 <phrase role="keyword">inline</phrase> <phrase role="keyword">void</phrase> <phrase role="identifier">do_destroy_array</phrase><phrase role="special">(</phrase><phrase role="identifier">T</phrase><phrase role="special">*</phrase> <phrase role="identifier">first</phrase><phrase role="special">,</phrase> <phrase role="identifier">T</phrase><phrase role="special">*</phrase> <phrase role="identifier">last</phrase><phrase role="special">,</phrase> <phrase role="keyword">const</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><link linkend="boost_typetraits.reference.integral_constant">true_type</link><phrase role="special">&amp;)</phrase>
1525 <phrase role="special">{</phrase>
1526 <phrase role="special">}</phrase>
1527
1528 <phrase role="special">}</phrase> <phrase role="comment">// namespace detail
1529 </phrase>
1530 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
1531 <phrase role="keyword">inline</phrase> <phrase role="keyword">void</phrase> <phrase role="identifier">destroy_array</phrase><phrase role="special">(</phrase><phrase role="identifier">T</phrase><phrase role="special">*</phrase> <phrase role="identifier">p1</phrase><phrase role="special">,</phrase> <phrase role="identifier">T</phrase><phrase role="special">*</phrase> <phrase role="identifier">p2</phrase><phrase role="special">)</phrase>
1532 <phrase role="special">{</phrase>
1533    <phrase role="identifier">detail</phrase><phrase role="special">::</phrase><phrase role="identifier">do_destroy_array</phrase><phrase role="special">(</phrase><phrase role="identifier">p1</phrase><phrase role="special">,</phrase> <phrase role="identifier">p2</phrase><phrase role="special">,</phrase> <phrase role="special">::</phrase><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><link linkend="boost_typetraits.reference.has_trivial_destructor">has_trivial_destructor</link><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;());</phrase>
1534 <phrase role="special">}</phrase>
1535 </programlisting>
1536     </section>
1537     <section id="boost_typetraits.examples.iter">
1538       <title><link linkend="boost_typetraits.examples.iter"> An improved Version
1539       of std::iter_swap</link></title>
1540       <para>
1541         Demonstrates a version of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">iter_swap</phrase></computeroutput>
1542         that use type traits to determine whether an it's arguments are proxying
1543         iterators or not, if they're not then it just does a <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">swap</phrase></computeroutput>
1544         of it's dereferenced arguments (the same as <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">iter_swap</phrase></computeroutput>
1545         does), however if they are proxying iterators then takes special care over
1546         the swap to ensure that the algorithm works correctly for both proxying iterators,
1547         and even iterators of different types (see <ulink url="../../examples/iter_swap_example.cpp">iter_swap_example.cpp</ulink>):
1548       </para>
1549
1550 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="comment">//
1551 </phrase><phrase role="comment">// iter_swap:
1552 </phrase><phrase role="comment">// tests whether iterator is a proxying iterator or not, and
1553 </phrase><phrase role="comment">// uses optimal form accordingly:
1554 </phrase><phrase role="comment">//
1555 </phrase><phrase role="keyword">namespace</phrase> <phrase role="identifier">detail</phrase><phrase role="special">{</phrase>
1556
1557 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">typename</phrase> <phrase role="identifier">I</phrase><phrase role="special">&gt;</phrase>
1558 <phrase role="keyword">static</phrase> <phrase role="keyword">void</phrase> <phrase role="identifier">do_swap</phrase><phrase role="special">(</phrase><phrase role="identifier">I</phrase> <phrase role="identifier">one</phrase><phrase role="special">,</phrase> <phrase role="identifier">I</phrase> <phrase role="identifier">two</phrase><phrase role="special">,</phrase> <phrase role="keyword">const</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><link linkend="boost_typetraits.reference.integral_constant">false_type</link><phrase role="special">&amp;)</phrase>
1559 <phrase role="special">{</phrase>
1560    <phrase role="keyword">typedef</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">iterator_traits</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">I</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase> <phrase role="identifier">v_t</phrase><phrase role="special">;</phrase>
1561    <phrase role="identifier">v_t</phrase> <phrase role="identifier">v</phrase> <phrase role="special">=</phrase> <phrase role="special">*</phrase><phrase role="identifier">one</phrase><phrase role="special">;</phrase>
1562    <phrase role="special">*</phrase><phrase role="identifier">one</phrase> <phrase role="special">=</phrase> <phrase role="special">*</phrase><phrase role="identifier">two</phrase><phrase role="special">;</phrase>
1563    <phrase role="special">*</phrase><phrase role="identifier">two</phrase> <phrase role="special">=</phrase> <phrase role="identifier">v</phrase><phrase role="special">;</phrase>
1564 <phrase role="special">}</phrase>
1565 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">typename</phrase> <phrase role="identifier">I</phrase><phrase role="special">&gt;</phrase>
1566 <phrase role="keyword">static</phrase> <phrase role="keyword">void</phrase> <phrase role="identifier">do_swap</phrase><phrase role="special">(</phrase><phrase role="identifier">I</phrase> <phrase role="identifier">one</phrase><phrase role="special">,</phrase> <phrase role="identifier">I</phrase> <phrase role="identifier">two</phrase><phrase role="special">,</phrase> <phrase role="keyword">const</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><link linkend="boost_typetraits.reference.integral_constant">true_type</link><phrase role="special">&amp;)</phrase>
1567 <phrase role="special">{</phrase>
1568    <phrase role="keyword">using</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">swap</phrase><phrase role="special">;</phrase>
1569    <phrase role="identifier">swap</phrase><phrase role="special">(*</phrase><phrase role="identifier">one</phrase><phrase role="special">,</phrase> <phrase role="special">*</phrase><phrase role="identifier">two</phrase><phrase role="special">);</phrase>
1570 <phrase role="special">}</phrase>
1571
1572 <phrase role="special">}</phrase>
1573
1574 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">typename</phrase> <phrase role="identifier">I1</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">I2</phrase><phrase role="special">&gt;</phrase>
1575 <phrase role="keyword">inline</phrase> <phrase role="keyword">void</phrase> <phrase role="identifier">iter_swap</phrase><phrase role="special">(</phrase><phrase role="identifier">I1</phrase> <phrase role="identifier">one</phrase><phrase role="special">,</phrase> <phrase role="identifier">I2</phrase> <phrase role="identifier">two</phrase><phrase role="special">)</phrase>
1576 <phrase role="special">{</phrase>
1577    <phrase role="comment">//
1578 </phrase>   <phrase role="comment">// See is both arguments are non-proxying iterators,
1579 </phrase>   <phrase role="comment">// and if both iterator the same type:
1580 </phrase>   <phrase role="comment">//
1581 </phrase>   <phrase role="keyword">typedef</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">iterator_traits</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">I1</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">reference</phrase> <phrase role="identifier">r1_t</phrase><phrase role="special">;</phrase>
1582    <phrase role="keyword">typedef</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">iterator_traits</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">I2</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">reference</phrase> <phrase role="identifier">r2_t</phrase><phrase role="special">;</phrase>
1583
1584    <phrase role="keyword">typedef</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><link linkend="boost_typetraits.reference.integral_constant">integral_constant</link><phrase role="special">&lt;</phrase><phrase role="keyword">bool</phrase><phrase role="special">,</phrase>
1585       <phrase role="special">::</phrase><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><link linkend="boost_typetraits.reference.is_reference">is_reference</link><phrase role="special">&lt;</phrase><phrase role="identifier">r1_t</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase>
1586       <phrase role="special">&amp;&amp;</phrase> <phrase role="special">::</phrase><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><link linkend="boost_typetraits.reference.is_reference">is_reference</link><phrase role="special">&lt;</phrase><phrase role="identifier">r2_t</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase>
1587       <phrase role="special">&amp;&amp;</phrase> <phrase role="special">::</phrase><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><link linkend="boost_typetraits.reference.is_same">is_same</link><phrase role="special">&lt;</phrase><phrase role="identifier">r1_t</phrase><phrase role="special">,</phrase> <phrase role="identifier">r2_t</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase><phrase role="special">&gt;</phrase> <phrase role="identifier">truth_type</phrase><phrase role="special">;</phrase>
1588
1589    <phrase role="identifier">detail</phrase><phrase role="special">::</phrase><phrase role="identifier">do_swap</phrase><phrase role="special">(</phrase><phrase role="identifier">one</phrase><phrase role="special">,</phrase> <phrase role="identifier">two</phrase><phrase role="special">,</phrase> <phrase role="identifier">truth_type</phrase><phrase role="special">());</phrase>
1590 <phrase role="special">}</phrase>
1591 </programlisting>
1592     </section>
1593     <section id="boost_typetraits.examples.to_double">
1594       <title><link linkend="boost_typetraits.examples.to_double"> Convert Numeric
1595       Types and Enums to double</link></title>
1596       <para>
1597         Demonstrates a conversion of <ulink url="../../../../libs/numeric/conversion/doc/html/boost_numericconversion/definitions.html#boost_numericconversion.definitions.numeric_types">Numeric
1598         Types</ulink> and enum types to double:
1599       </para>
1600
1601 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
1602 <phrase role="keyword">inline</phrase> <phrase role="keyword">double</phrase> <phrase role="identifier">to_double</phrase><phrase role="special">(</phrase><phrase role="identifier">T</phrase> <phrase role="keyword">const</phrase><phrase role="special">&amp;</phrase> <phrase role="identifier">value</phrase><phrase role="special">)</phrase>
1603 <phrase role="special">{</phrase>
1604     <phrase role="keyword">typedef</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">promote</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase> <phrase role="identifier">promoted</phrase><phrase role="special">;</phrase>
1605     <phrase role="keyword">return</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">numeric</phrase><phrase role="special">::</phrase><phrase role="identifier">converter</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">double</phrase><phrase role="special">,</phrase><phrase role="identifier">promoted</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">convert</phrase><phrase role="special">(</phrase><phrase role="identifier">value</phrase><phrase role="special">);</phrase>
1606 <phrase role="special">}</phrase>
1607 </programlisting>
1608     </section>
1609   </section>
1610   <section id="boost_typetraits.reference">
1611     <title><link linkend="boost_typetraits.reference"> Alphabetical Reference</link></title>
1612     <section id="boost_typetraits.reference.add_const"><indexterm type="class_name"><primary>Constrained Index Term</primary><secondary>add_const</secondary></indexterm><indexterm><primary>add_const</primary><secondary>Constrained Index Term</secondary></indexterm><indexterm type="class_name"><primary>Constrained Index Term</primary><secondary>add_const</secondary></indexterm><indexterm><primary>add_const</primary><secondary>Constrained Index Term</secondary></indexterm><indexterm type="class_name"><primary>add_const</primary><secondary>add_const</secondary></indexterm><indexterm type="class_name"><primary>Constrained Index Term</primary><secondary>add_const</secondary></indexterm><indexterm><primary>add_const</primary><secondary>Constrained Index Term</secondary></indexterm><indexterm type="class_name"><primary>Constrained Index Term</primary><secondary>add_const</secondary></indexterm><indexterm><primary>add_const</primary><secondary>Constrained Index Term</secondary></indexterm>
1613       <title><link linkend="boost_typetraits.reference.add_const"> add_const</link></title>
1614        <indexterm type="class_name">
1615           <primary>one</primary>
1616           <secondary>two</secondary>
1617        </indexterm>
1618
1619        <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
1620 <phrase role="keyword">struct</phrase> <phrase role="identifier">add_const</phrase>
1621 <phrase role="special">{</phrase>
1622    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
1623 <phrase role="special">};</phrase>
1624 </programlisting>
1625       <para>
1626         <emphasis role="bold">type:</emphasis> The same type as <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase>
1627         <phrase role="keyword">const</phrase></computeroutput> for all <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>.
1628       </para>
1629       <para>
1630         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.3.
1631       </para>
1632       <para>
1633         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
1634         does not support partial specialization of class-templates then this template
1635         will compile, but the member <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">type</phrase></computeroutput>
1636         will always be the same as type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>
1637         except where <link linkend="boost_typetraits.category.transform.broken_compiler_workarounds_">compiler
1638         workarounds</link> have been applied.
1639       </para>
1640       <para>
1641         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
1642         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">add_const</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
1643         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
1644       </para>
1645       <table frame="all"> <title>Examples</title>
1646       <tgroup cols="2">
1647         <thead>
1648           <row>
1649             <entry>
1650             <para>
1651               Expression
1652             </para>
1653             </entry><entry>
1654             <para>
1655               Result Type
1656             </para>
1657             </entry>
1658           </row>
1659         </thead>
1660         <tbody>
1661           <row>
1662             <entry>
1663             <para>
1664               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_const</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
1665             </para>
1666             </entry><entry>
1667             <para>
1668               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase></computeroutput>
1669             </para>
1670             </entry>
1671           </row>
1672           <row>
1673             <entry>
1674             <para>
1675               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_const</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
1676             </para>
1677             </entry><entry>
1678             <para>
1679               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">&amp;</phrase></computeroutput>
1680             </para>
1681             </entry>
1682           </row>
1683           <row>
1684             <entry>
1685             <para>
1686               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_const</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
1687             </para>
1688             </entry><entry>
1689             <para>
1690               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">*</phrase>
1691               <phrase role="keyword">const</phrase></computeroutput>
1692             </para>
1693             </entry>
1694           </row>
1695           <row>
1696             <entry>
1697             <para>
1698               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_const</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
1699             </para>
1700             </entry><entry>
1701             <para>
1702               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase></computeroutput>
1703             </para>
1704             </entry>
1705           </row>
1706         </tbody>
1707       </tgroup>
1708       </table>
1709     </section>
1710     <section id="boost_typetraits.reference.add_cv"><indexterm type="class_name"><primary>add_cv</primary><secondary>add_cv</secondary></indexterm>
1711       <title><link linkend="boost_typetraits.reference.add_cv"> add_cv</link></title>
1712        <indexterm type="class_name">
1713           <primary>one</primary>
1714           <secondary>two</secondary>
1715           <tertiary>three</tertiary>
1716        </indexterm>
1717
1718        <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
1719 <phrase role="keyword">struct</phrase> <phrase role="identifier">add_cv</phrase>
1720 <phrase role="special">{</phrase>
1721    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
1722 <phrase role="special">};</phrase>
1723 </programlisting>
1724       <para>
1725         <emphasis role="bold">type:</emphasis> The same type as <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase>
1726         <phrase role="keyword">const</phrase> <phrase role="keyword">volatile</phrase></computeroutput>
1727         for all <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>.
1728       </para>
1729       <para>
1730         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.3.
1731       </para>
1732       <para>
1733         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
1734         does not support partial specialization of class-templates then this template
1735         will compile, but the member <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">type</phrase></computeroutput>
1736         will always be the same as type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>
1737         except where <link linkend="boost_typetraits.category.transform.broken_compiler_workarounds_">compiler
1738         workarounds</link> have been applied.
1739       </para>
1740       <para>
1741         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
1742         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">add_cv</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
1743         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
1744       </para>
1745       <table frame="all"> <title>Examples</title>
1746       <tgroup cols="2">
1747         <thead>
1748           <row>
1749             <entry>
1750             <para>
1751               Expression
1752             </para>
1753             </entry><entry>
1754             <para>
1755               Result Type
1756             </para>
1757             </entry>
1758           </row>
1759         </thead>
1760         <tbody>
1761           <row>
1762             <entry>
1763             <para>
1764               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_cv</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
1765             </para>
1766             </entry><entry>
1767             <para>
1768               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase>
1769               <phrase role="keyword">volatile</phrase></computeroutput>
1770             </para>
1771             </entry>
1772           </row>
1773           <row>
1774             <entry>
1775             <para>
1776               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_cv</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
1777             </para>
1778             </entry><entry>
1779             <para>
1780               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">&amp;</phrase></computeroutput>
1781             </para>
1782             </entry>
1783           </row>
1784           <row>
1785             <entry>
1786             <para>
1787               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_cv</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
1788             </para>
1789             </entry><entry>
1790             <para>
1791               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">*</phrase>
1792               <phrase role="keyword">const</phrase> <phrase role="keyword">volatile</phrase></computeroutput>
1793             </para>
1794             </entry>
1795           </row>
1796           <row>
1797             <entry>
1798             <para>
1799               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_cv</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
1800             </para>
1801             </entry><entry>
1802             <para>
1803               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase>
1804               <phrase role="keyword">volatile</phrase></computeroutput>
1805             </para>
1806             </entry>
1807           </row>
1808         </tbody>
1809       </tgroup>
1810       </table>
1811     </section>
1812     <section id="boost_typetraits.reference.add_pointer"><indexterm type="class_name"><primary>add_pointer</primary><secondary>add_pointer</secondary></indexterm>
1813       <title><link linkend="boost_typetraits.reference.add_pointer"> add_pointer</link></title>
1814
1815 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
1816 <phrase role="keyword">struct</phrase> <phrase role="identifier">add_pointer</phrase>
1817 <phrase role="special">{</phrase>
1818    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
1819 <phrase role="special">};</phrase>
1820 </programlisting>
1821       <para>
1822         <emphasis role="bold">type:</emphasis> The same type as <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_reference</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase><phrase role="special">*</phrase></computeroutput>.
1823       </para>
1824       <para>
1825         The rationale for this template is that it produces the same type as <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">TYPEOF</phrase><phrase role="special">(&amp;</phrase><phrase role="identifier">t</phrase><phrase role="special">)</phrase></computeroutput>, where
1826         <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">t</phrase></computeroutput> is an object of type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>.
1827       </para>
1828       <para>
1829         <emphasis role="bold">C++ Standard Reference:</emphasis> 8.3.1.
1830       </para>
1831       <para>
1832         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
1833         does not support partial specialization of class-templates then this template
1834         will compile, but the member <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">type</phrase></computeroutput>
1835         will always be the same as type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>
1836         except where <link linkend="boost_typetraits.category.transform.broken_compiler_workarounds_">compiler
1837         workarounds</link> have been applied.
1838       </para>
1839       <para>
1840         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
1841         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">add_pointer</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
1842         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
1843       </para>
1844       <table frame="all"> <title>Examples</title>
1845       <tgroup cols="2">
1846         <thead>
1847           <row>
1848             <entry>
1849             <para>
1850               Expression
1851             </para>
1852             </entry><entry>
1853             <para>
1854               Result Type
1855             </para>
1856             </entry>
1857           </row>
1858         </thead>
1859         <tbody>
1860           <row>
1861             <entry>
1862             <para>
1863               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
1864             </para>
1865             </entry><entry>
1866             <para>
1867               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">*</phrase></computeroutput>
1868             </para>
1869             </entry>
1870           </row>
1871           <row>
1872             <entry>
1873             <para>
1874               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
1875             </para>
1876             </entry><entry>
1877             <para>
1878               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">*</phrase></computeroutput>
1879             </para>
1880             </entry>
1881           </row>
1882           <row>
1883             <entry>
1884             <para>
1885               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
1886             </para>
1887             </entry><entry>
1888             <para>
1889               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">**</phrase></computeroutput>
1890             </para>
1891             </entry>
1892           </row>
1893           <row>
1894             <entry>
1895             <para>
1896               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">*&amp;&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
1897             </para>
1898             </entry><entry>
1899             <para>
1900               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">**</phrase></computeroutput>
1901             </para>
1902             </entry>
1903           </row>
1904         </tbody>
1905       </tgroup>
1906       </table>
1907     </section>
1908     <section id="boost_typetraits.reference.add_reference"><indexterm type="class_name"><primary>add_reference</primary><secondary>add_reference</secondary></indexterm>
1909       <title><link linkend="boost_typetraits.reference.add_reference"> add_reference</link></title>
1910
1911 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
1912 <phrase role="keyword">struct</phrase> <phrase role="identifier">add_reference</phrase>
1913 <phrase role="special">{</phrase>
1914    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
1915 <phrase role="special">};</phrase>
1916 </programlisting>
1917       <para>
1918         <emphasis role="bold">type:</emphasis> If <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>
1919         is not a reference type then <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase><phrase role="special">&amp;</phrase></computeroutput>, otherwise <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>.
1920       </para>
1921       <para>
1922         <emphasis role="bold">C++ Standard Reference:</emphasis> 8.3.2.
1923       </para>
1924       <para>
1925         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
1926         does not support partial specialization of class-templates then this template
1927         will compile, but the member <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">type</phrase></computeroutput>
1928         will always be the same as type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>
1929         except where <link linkend="boost_typetraits.category.transform.broken_compiler_workarounds_">compiler
1930         workarounds</link> have been applied.
1931       </para>
1932       <para>
1933         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
1934         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">add_reference</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
1935         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
1936       </para>
1937       <table frame="all"> <title>Examples</title>
1938       <tgroup cols="2">
1939         <thead>
1940           <row>
1941             <entry>
1942             <para>
1943               Expression
1944             </para>
1945             </entry><entry>
1946             <para>
1947               Result Type
1948             </para>
1949             </entry>
1950           </row>
1951         </thead>
1952         <tbody>
1953           <row>
1954             <entry>
1955             <para>
1956               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_reference</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
1957             </para>
1958             </entry><entry>
1959             <para>
1960               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">&amp;</phrase></computeroutput>
1961             </para>
1962             </entry>
1963           </row>
1964           <row>
1965             <entry>
1966             <para>
1967               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_reference</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
1968             </para>
1969             </entry><entry>
1970             <para>
1971               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">&amp;</phrase></computeroutput>
1972             </para>
1973             </entry>
1974           </row>
1975           <row>
1976             <entry>
1977             <para>
1978               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_reference</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
1979             </para>
1980             </entry><entry>
1981             <para>
1982               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">*&amp;</phrase></computeroutput>
1983             </para>
1984             </entry>
1985           </row>
1986           <row>
1987             <entry>
1988             <para>
1989               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_reference</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">*&amp;&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
1990             </para>
1991             </entry><entry>
1992             <para>
1993               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">*&amp;</phrase></computeroutput>
1994             </para>
1995             </entry>
1996           </row>
1997         </tbody>
1998       </tgroup>
1999       </table>
2000     </section>
2001     <section id="boost_typetraits.reference.add_volatile"><indexterm type="class_name"><primary>add_volatile</primary><secondary>add_volatile</secondary></indexterm>
2002       <title><link linkend="boost_typetraits.reference.add_volatile"> add_volatile</link></title>
2003        <indexterm type="class_name">
2004           <primary>one</primary>
2005        </indexterm>
2006
2007        <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
2008 <phrase role="keyword">struct</phrase> <phrase role="identifier">add_volatile</phrase>
2009 <phrase role="special">{</phrase>
2010    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
2011 <phrase role="special">};</phrase>
2012 </programlisting>
2013       <para>
2014         <emphasis role="bold">type:</emphasis> The same type as <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase>
2015         <phrase role="keyword">volatile</phrase></computeroutput> for all <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>.
2016       </para>
2017       <para>
2018         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.3.
2019       </para>
2020       <para>
2021         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
2022         does not support partial specialization of class-templates then this template
2023         will compile, but the member <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">type</phrase></computeroutput>
2024         will always be the same as type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>
2025         except where <link linkend="boost_typetraits.category.transform.broken_compiler_workarounds_">compiler
2026         workarounds</link> have been applied.
2027       </para>
2028       <para>
2029         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
2030         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">add_volatile</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2031         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2032       </para>
2033       <table frame="all"> <title>Examples</title>
2034       <tgroup cols="2">
2035         <thead>
2036           <row>
2037             <entry>
2038             <para>
2039               Expression
2040             </para>
2041             </entry><entry>
2042             <para>
2043               Result Type
2044             </para>
2045             </entry>
2046           </row>
2047         </thead>
2048         <tbody>
2049           <row>
2050             <entry>
2051             <para>
2052               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_volatile</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
2053             </para>
2054             </entry><entry>
2055             <para>
2056               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">volatile</phrase></computeroutput>
2057             </para>
2058             </entry>
2059           </row>
2060           <row>
2061             <entry>
2062             <para>
2063               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_volatile</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
2064             </para>
2065             </entry><entry>
2066             <para>
2067               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">&amp;</phrase></computeroutput>
2068             </para>
2069             </entry>
2070           </row>
2071           <row>
2072             <entry>
2073             <para>
2074               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_volatile</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
2075             </para>
2076             </entry><entry>
2077             <para>
2078               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">*</phrase>
2079               <phrase role="keyword">volatile</phrase></computeroutput>
2080             </para>
2081             </entry>
2082           </row>
2083           <row>
2084             <entry>
2085             <para>
2086               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">add_volatile</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
2087             </para>
2088             </entry><entry>
2089             <para>
2090               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase>
2091               <phrase role="keyword">volatile</phrase></computeroutput>
2092             </para>
2093             </entry>
2094           </row>
2095         </tbody>
2096       </tgroup>
2097       </table>
2098     </section>
2099     <section id="boost_typetraits.reference.aligned_storage"><indexterm type="class_name"><primary>aligned_storage</primary><secondary>aligned_storage</secondary></indexterm>
2100       <title><link linkend="boost_typetraits.reference.aligned_storage"> aligned_storage</link></title>
2101
2102 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">Size</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">Align</phrase><phrase role="special">&gt;</phrase>
2103 <phrase role="keyword">struct</phrase> <phrase role="identifier">aligned_storage</phrase>
2104 <phrase role="special">{</phrase>
2105    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
2106 <phrase role="special">};</phrase>
2107 </programlisting>
2108       <para>
2109         <emphasis role="bold">type:</emphasis> a built-in or POD type with size
2110         <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">Size</phrase></computeroutput> and an alignment that
2111         is a multiple of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">Align</phrase></computeroutput>.
2112       </para>
2113       <para>
2114         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
2115         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">aligned_storage</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2116         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2117       </para>
2118     </section>
2119     <section id="boost_typetraits.reference.alignment_of"><indexterm type="class_name"><primary>integral_constant</primary><secondary>alignment_of</secondary></indexterm><indexterm><primary>alignment_of</primary><secondary>integral_constant</secondary></indexterm><indexterm type="class_name"><primary>alignment_of</primary><secondary>alignment_of</secondary></indexterm>
2120       <title><link linkend="boost_typetraits.reference.alignment_of"> alignment_of</link></title>
2121
2122 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
2123 <phrase role="keyword">struct</phrase> <phrase role="identifier">alignment_of</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <link linkend="boost_typetraits.reference.integral_constant">integral_constant</link><phrase role="special">&lt;</phrase><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase><phrase role="special">,</phrase> <phrase role="identifier">ALIGNOF</phrase><phrase role="special">(</phrase><phrase role="identifier">T</phrase><phrase role="special">)&gt;</phrase> <phrase role="special">{};</phrase>
2124 </programlisting>
2125       <para>
2126         <emphasis role="bold">Inherits:</emphasis> Class template alignment<emphasis role="underline">of inherits from `</emphasis>_integral_constant&lt;std::size_t,
2127         ALIGNOF(T)&gt;<computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="special">,</phrase> <phrase role="identifier">where</phrase>
2128         </computeroutput>ALIGNOF(T)` is the alignment of type T.
2129       </para>
2130       <para>
2131         <emphasis>Note: strictly speaking you should only rely on the value of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">ALIGNOF</phrase><phrase role="special">(</phrase><phrase role="identifier">T</phrase><phrase role="special">)</phrase></computeroutput> being
2132         a multiple of the true alignment of T, although in practice it does compute
2133         the correct value in all the cases we know about.</emphasis>
2134       </para>
2135       <para>
2136         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
2137         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">alignment_of</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2138         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2139       </para>
2140       <para>
2141         <emphasis role="bold">Examples:</emphasis>
2142       </para>
2143       <blockquote>
2144         <para>
2145           <para>
2146             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">alignment_of</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;</phrase></computeroutput>
2147             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">integral_constant</link><phrase role="special">&lt;</phrase><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase><phrase role="special">,</phrase> <phrase role="identifier">ALIGNOF</phrase><phrase role="special">(</phrase><phrase role="keyword">int</phrase><phrase role="special">)&gt;</phrase></computeroutput>.
2148           </para>
2149         </para>
2150       </blockquote>
2151       <blockquote>
2152         <para>
2153           <para>
2154             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">alignment_of</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">integral_constant</link><phrase role="special">&lt;</phrase><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase><phrase role="special">,</phrase> <phrase role="identifier">ALIGNOF</phrase><phrase role="special">(</phrase><phrase role="keyword">char</phrase><phrase role="special">)&gt;</phrase></computeroutput>.
2155           </para>
2156         </para>
2157       </blockquote>
2158       <blockquote>
2159         <para>
2160           <para>
2161             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">alignment_of</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">double</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
2162             with value <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">ALIGNOF</phrase><phrase role="special">(</phrase><phrase role="keyword">double</phrase><phrase role="special">)</phrase></computeroutput>.
2163           </para>
2164         </para>
2165       </blockquote>
2166       <blockquote>
2167         <para>
2168           <para>
2169             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">alignment_of</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase></computeroutput>.
2170           </para>
2171         </para>
2172       </blockquote>
2173     </section>
2174     <section id="boost_typetraits.reference.decay"><indexterm type="class_name"><primary>decay</primary><secondary>decay</secondary></indexterm>
2175       <title><link linkend="boost_typetraits.reference.decay"> decay</link></title>
2176
2177 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
2178 <phrase role="keyword">struct</phrase> <phrase role="identifier">decay</phrase>
2179 <phrase role="special">{</phrase>
2180    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
2181 <phrase role="special">};</phrase>
2182 </programlisting>
2183       <para>
2184         <emphasis role="bold">type:</emphasis> Let <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">U</phrase></computeroutput>
2185         be the result of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_reference</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>, then if <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">U</phrase></computeroutput>
2186         is an array type, the result is <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_extent</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">U</phrase><phrase role="special">&gt;*</phrase></computeroutput>,
2187         otherwise if <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">U</phrase></computeroutput> is a function
2188         type then the result is <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">U</phrase><phrase role="special">*</phrase></computeroutput>, otherwise the result is <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">U</phrase></computeroutput>.
2189       </para>
2190       <para>
2191         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.1.
2192       </para>
2193       <para>
2194         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
2195         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">decay</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2196         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2197       </para>
2198       <table frame="all"> <title>Examples</title>
2199       <tgroup cols="2">
2200         <thead>
2201           <row>
2202             <entry>
2203             <para>
2204               Expression
2205             </para>
2206             </entry><entry>
2207             <para>
2208               Result Type
2209             </para>
2210             </entry>
2211           </row>
2212         </thead>
2213         <tbody>
2214           <row>
2215             <entry>
2216             <para>
2217               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">decay</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">[</phrase><phrase role="number">2</phrase><phrase role="special">][</phrase><phrase role="number">3</phrase><phrase role="special">]&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
2218             </para>
2219             </entry><entry>
2220             <para>
2221               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">[</phrase><phrase role="number">2</phrase><phrase role="special">]*</phrase></computeroutput>
2222             </para>
2223             </entry>
2224           </row>
2225           <row>
2226             <entry>
2227             <para>
2228               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">decay</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">(&amp;)[</phrase><phrase role="number">2</phrase><phrase role="special">]&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
2229             </para>
2230             </entry><entry>
2231             <para>
2232               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">*</phrase></computeroutput>
2233             </para>
2234             </entry>
2235           </row>
2236           <row>
2237             <entry>
2238             <para>
2239               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">decay</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">(&amp;)(</phrase><phrase role="keyword">double</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
2240             </para>
2241             </entry><entry>
2242             <para>
2243               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">(*)(</phrase><phrase role="keyword">double</phrase><phrase role="special">)</phrase></computeroutput>
2244             </para>
2245             </entry>
2246           </row>
2247           <row>
2248             <entry>
2249             <para>
2250               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">(*)(</phrase><phrase role="keyword">double</phrase></computeroutput>
2251             </para>
2252             </entry><entry>
2253             <para>
2254               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">(*)(</phrase><phrase role="keyword">double</phrase><phrase role="special">)</phrase></computeroutput>
2255             </para>
2256             </entry>
2257           </row>
2258           <row>
2259             <entry>
2260             <para>
2261               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">(</phrase><phrase role="keyword">double</phrase><phrase role="special">)</phrase></computeroutput>
2262             </para>
2263             </entry><entry>
2264             <para>
2265               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">(*)(</phrase><phrase role="keyword">double</phrase><phrase role="special">)</phrase></computeroutput>
2266             </para>
2267             </entry>
2268           </row>
2269         </tbody>
2270       </tgroup>
2271       </table>
2272     </section>
2273     <section id="boost_typetraits.reference.extent"><indexterm type="class_name"><primary>integral_constant</primary><secondary>extent</secondary></indexterm><indexterm><primary>extent</primary><secondary>integral_constant</secondary></indexterm><indexterm type="class_name"><primary>extent</primary><secondary>extent</secondary></indexterm>
2274       <title><link linkend="boost_typetraits.reference.extent"> extent</link></title>
2275
2276 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">N</phrase> <phrase role="special">=</phrase> <phrase role="number">0</phrase><phrase role="special">&gt;</phrase>
2277 <phrase role="keyword">struct</phrase> <phrase role="identifier">extent</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <link linkend="boost_typetraits.reference.integral_constant">integral_constant</link><phrase role="special">&lt;</phrase><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase><phrase role="special">,</phrase> <phrase role="identifier">EXTENT</phrase><phrase role="special">(</phrase><phrase role="identifier">T</phrase><phrase role="special">,</phrase><phrase role="identifier">N</phrase><phrase role="special">)&gt;</phrase> <phrase role="special">{};</phrase>
2278 </programlisting>
2279       <para>
2280         <emphasis role="bold">Inherits:</emphasis> Class template extent inherits
2281         from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">integral_constant</link><phrase role="special">&lt;</phrase><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase><phrase role="special">,</phrase> <phrase role="identifier">EXTENT</phrase><phrase role="special">(</phrase><phrase role="identifier">T</phrase><phrase role="special">,</phrase><phrase role="identifier">N</phrase><phrase role="special">)&gt;</phrase></computeroutput>,
2282         where <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">EXTENT</phrase><phrase role="special">(</phrase><phrase role="identifier">T</phrase><phrase role="special">,</phrase><phrase role="identifier">N</phrase><phrase role="special">)</phrase></computeroutput> is the number of elements in the N'th array
2283         dimention of type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>.
2284       </para>
2285       <para>
2286         If <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput> is not an array type,
2287         or if <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">N</phrase> <phrase role="special">&gt;</phrase>
2288         <link linkend="boost_typetraits.reference.rank">rank</link><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>, or if the N'th array bound is incomplete,
2289         then <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">EXTENT</phrase><phrase role="special">(</phrase><phrase role="identifier">T</phrase><phrase role="special">,</phrase><phrase role="identifier">N</phrase><phrase role="special">)</phrase></computeroutput> is zero.
2290       </para>
2291       <para>
2292         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
2293         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">extent</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2294         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2295       </para>
2296       <para>
2297         <emphasis role="bold">Examples:</emphasis>
2298       </para>
2299       <blockquote>
2300         <para>
2301           <para>
2302             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">extent</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">[</phrase><phrase role="number">1</phrase><phrase role="special">]&gt;</phrase></computeroutput> inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">integral_constant</link><phrase role="special">&lt;</phrase><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase><phrase role="special">,</phrase> <phrase role="number">1</phrase><phrase role="special">&gt;</phrase></computeroutput>.
2303           </para>
2304         </para>
2305       </blockquote>
2306       <blockquote>
2307         <para>
2308           <para>
2309             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">extent</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">double</phrase><phrase role="special">[</phrase><phrase role="number">2</phrase><phrase role="special">][</phrase><phrase role="number">3</phrase><phrase role="special">][</phrase><phrase role="number">4</phrase><phrase role="special">],</phrase>
2310             <phrase role="number">1</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">integral_constant</link><phrase role="special">&lt;</phrase><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase><phrase role="special">,</phrase> <phrase role="number">3</phrase><phrase role="special">&gt;</phrase></computeroutput>.
2311           </para>
2312         </para>
2313       </blockquote>
2314       <blockquote>
2315         <para>
2316           <para>
2317             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">extent</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">[</phrase><phrase role="number">4</phrase><phrase role="special">]&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
2318             is an integral constant expression that evaluates to <emphasis>4</emphasis>.
2319           </para>
2320         </para>
2321       </blockquote>
2322       <blockquote>
2323         <para>
2324           <para>
2325             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">extent</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">[][</phrase><phrase role="number">2</phrase><phrase role="special">]&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
2326             that evaluates to <emphasis>0</emphasis>.
2327           </para>
2328         </para>
2329       </blockquote>
2330       <blockquote>
2331         <para>
2332           <para>
2333             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">extent</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">[][</phrase><phrase role="number">2</phrase><phrase role="special">],</phrase> <phrase role="number">1</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
2334             is an integral constant expression that evaluates to <emphasis>2</emphasis>.
2335           </para>
2336         </para>
2337       </blockquote>
2338       <blockquote>
2339         <para>
2340           <para>
2341             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">extent</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
2342             that evaluates to <emphasis>0</emphasis>.
2343           </para>
2344         </para>
2345       </blockquote>
2346       <blockquote>
2347         <para>
2348           <para>
2349             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">extent</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase></computeroutput>.
2350           </para>
2351         </para>
2352       </blockquote>
2353     </section>
2354     <section id="boost_typetraits.reference.floating_point_promotion"><indexterm type="class_name"><primary>floating_point_promotion</primary><secondary>floating_point_promotion</secondary></indexterm>
2355       <title><link linkend="boost_typetraits.reference.floating_point_promotion">
2356       floating_point_promotion</link></title>
2357 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
2358 <phrase role="keyword">struct</phrase> <phrase role="identifier">floating_point_promotion</phrase>
2359 <phrase role="special">{</phrase>
2360    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
2361 <phrase role="special">};</phrase>
2362 </programlisting>
2363       <para>
2364         <emphasis role="bold">type:</emphasis> If floating point promotion can be
2365         applied to an rvalue of type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>,
2366         then applies floating point promotion to <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>
2367         and keeps cv-qualifiers of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>,
2368         otherwise leaves <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput> unchanged.
2369       </para>
2370       <para>
2371         <emphasis role="bold">C++ Standard Reference:</emphasis> 4.6.
2372       </para>
2373       <para>
2374         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
2375         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">floating_point_promotion</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2376         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2377       </para>
2378       <table frame="all"> <title>Examples</title>
2379       <tgroup cols="2">
2380         <thead>
2381           <row>
2382             <entry>
2383             <para>
2384               Expression
2385             </para>
2386             </entry><entry>
2387             <para>
2388               Result Type
2389             </para>
2390             </entry>
2391           </row>
2392         </thead>
2393         <tbody>
2394           <row>
2395             <entry>
2396             <para>
2397               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">floating_point_promotion</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">float</phrase>
2398               <phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
2399             </para>
2400             </entry><entry>
2401             <para>
2402               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">double</phrase> <phrase role="keyword">const</phrase></computeroutput>
2403             </para>
2404             </entry>
2405           </row>
2406           <row>
2407             <entry>
2408             <para>
2409               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">floating_point_promotion</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">float</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
2410             </para>
2411             </entry><entry>
2412             <para>
2413               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">float</phrase><phrase role="special">&amp;</phrase></computeroutput>
2414             </para>
2415             </entry>
2416           </row>
2417           <row>
2418             <entry>
2419             <para>
2420               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">floating_point_promotion</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">short</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
2421             </para>
2422             </entry><entry>
2423             <para>
2424               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">short</phrase></computeroutput>
2425             </para>
2426             </entry>
2427           </row>
2428         </tbody>
2429       </tgroup>
2430       </table>
2431     </section>
2432     <section id="boost_typetraits.reference.function_traits"><indexterm type="typedef_name"><primary>result_type</primary><secondary>function_traits</secondary></indexterm><indexterm><primary>function_traits</primary><secondary>result_type</secondary></indexterm><indexterm type="class_name"><primary>function_traits</primary><secondary>function_traits</secondary></indexterm>
2433       <title><link linkend="boost_typetraits.reference.function_traits"> function_traits</link></title>
2434
2435 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">F</phrase><phrase role="special">&gt;</phrase>
2436 <phrase role="keyword">struct</phrase> <phrase role="identifier">function_traits</phrase>
2437 <phrase role="special">{</phrase>
2438    <phrase role="keyword">static</phrase> <phrase role="keyword">const</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase>    <phrase role="identifier">arity</phrase> <phrase role="special">=</phrase> <replaceable>see-below</replaceable><phrase role="special">;</phrase>
2439    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable>           <phrase role="identifier">result_type</phrase><phrase role="special">;</phrase>
2440    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable>           arg<replaceable>N</replaceable>_type<phrase role="special">;</phrase>
2441 <phrase role="special">};</phrase>
2442 </programlisting>
2443       <para>
2444         The class template function_traits will only compile if:
2445       </para>
2446       <itemizedlist>
2447         <listitem>
2448           The compiler supports partial specialization of class templates.
2449         </listitem>
2450         <listitem>
2451           The template argument <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">F</phrase></computeroutput>
2452           is a <emphasis>function type</emphasis>, note that this <emphasis><emphasis role="bold">is not</emphasis></emphasis> the same thing as a <emphasis>pointer
2453           to a function</emphasis>.
2454         </listitem>
2455       </itemizedlist>
2456       <tip>
2457         <para>
2458           function_traits is intended to introspect only C++ functions of the form
2459           R (), R( A1 ), R ( A1, ... etc. ) and not function pointers or class member
2460           functions. To convert a function pointer type to a suitable type use <link linkend="boost_typetraits.reference.remove_pointer">remove_pointer</link>.
2461         </para>
2462       </tip>
2463       <table frame="all"> <title>Function Traits Members</title>
2464       <tgroup cols="2">
2465         <thead>
2466           <row>
2467             <entry>
2468             <para>
2469               Member
2470             </para>
2471             </entry><entry>
2472             <para>
2473               Description
2474             </para>
2475             </entry>
2476           </row>
2477         </thead>
2478         <tbody>
2479           <row>
2480             <entry>
2481             <para>
2482               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">function_traits</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">F</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">arity</phrase></computeroutput>
2483             </para>
2484             </entry><entry>
2485             <para>
2486               An integral constant expression that gives the number of arguments
2487               accepted by the function type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">F</phrase></computeroutput>.
2488             </para>
2489             </entry>
2490           </row>
2491           <row>
2492             <entry>
2493             <para>
2494               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">function_traits</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">F</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">result_type</phrase></computeroutput>
2495             </para>
2496             </entry><entry>
2497             <para>
2498               The type returned by function type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">F</phrase></computeroutput>.
2499             </para>
2500             </entry>
2501           </row>
2502           <row>
2503             <entry>
2504             <para>
2505               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">function_traits</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">F</phrase><phrase role="special">&gt;::</phrase>arg<replaceable>N</replaceable>_type</computeroutput>
2506             </para>
2507             </entry><entry>
2508             <para>
2509               The <replaceable>N</replaceable>th argument type of function type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">F</phrase></computeroutput>,
2510               where <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="number">1</phrase> <phrase role="special">&lt;=</phrase>
2511               <phrase role="identifier">N</phrase> <phrase role="special">&lt;=</phrase>
2512               <phrase role="identifier">arity</phrase></computeroutput> of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">F</phrase></computeroutput>.
2513             </para>
2514             </entry>
2515           </row>
2516         </tbody>
2517       </tgroup>
2518       </table> <table frame="all"> <title>Examples</title>
2519       <tgroup cols="2">
2520         <thead>
2521           <row>
2522             <entry>
2523             <para>
2524               Expression
2525             </para>
2526             </entry><entry>
2527             <para>
2528               Result
2529             </para>
2530             </entry>
2531           </row>
2532         </thead>
2533         <tbody>
2534           <row>
2535             <entry>
2536             <para>
2537               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">function_traits</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">void</phrase> <phrase role="special">(</phrase><phrase role="keyword">void</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">arity</phrase></computeroutput>
2538             </para>
2539             </entry><entry>
2540             <para>
2541               An integral constant expression that has the value 0.
2542             </para>
2543             </entry>
2544           </row>
2545           <row>
2546             <entry>
2547             <para>
2548               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">function_traits</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">long</phrase> <phrase role="special">(</phrase><phrase role="keyword">int</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">arity</phrase></computeroutput>
2549             </para>
2550             </entry><entry>
2551             <para>
2552               An integral constant expression that has the value 1.
2553             </para>
2554             </entry>
2555           </row>
2556           <row>
2557             <entry>
2558             <para>
2559               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">function_traits</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">long</phrase> <phrase role="special">(</phrase><phrase role="keyword">int</phrase><phrase role="special">,</phrase> <phrase role="keyword">long</phrase><phrase role="special">,</phrase> <phrase role="keyword">double</phrase><phrase role="special">,</phrase> <phrase role="keyword">void</phrase><phrase role="special">*)&gt;::</phrase><phrase role="identifier">arity</phrase></computeroutput>
2560             </para>
2561             </entry><entry>
2562             <para>
2563               An integral constant expression that has the value 4.
2564             </para>
2565             </entry>
2566           </row>
2567           <row>
2568             <entry>
2569             <para>
2570               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">function_traits</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">void</phrase> <phrase role="special">(</phrase><phrase role="keyword">void</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">result_type</phrase></computeroutput>
2571             </para>
2572             </entry><entry>
2573             <para>
2574               The type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">void</phrase></computeroutput>.
2575             </para>
2576             </entry>
2577           </row>
2578           <row>
2579             <entry>
2580             <para>
2581               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">function_traits</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">long</phrase> <phrase role="special">(</phrase><phrase role="keyword">int</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">result_type</phrase></computeroutput>
2582             </para>
2583             </entry><entry>
2584             <para>
2585               The type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">long</phrase></computeroutput>.
2586             </para>
2587             </entry>
2588           </row>
2589           <row>
2590             <entry>
2591             <para>
2592               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">function_traits</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">long</phrase> <phrase role="special">(</phrase><phrase role="keyword">int</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">arg1_type</phrase></computeroutput>
2593             </para>
2594             </entry><entry>
2595             <para>
2596               The type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase></computeroutput>.
2597             </para>
2598             </entry>
2599           </row>
2600           <row>
2601             <entry>
2602             <para>
2603               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">function_traits</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">long</phrase> <phrase role="special">(</phrase><phrase role="keyword">int</phrase><phrase role="special">,</phrase> <phrase role="keyword">long</phrase><phrase role="special">,</phrase> <phrase role="keyword">double</phrase><phrase role="special">,</phrase> <phrase role="keyword">void</phrase><phrase role="special">*)&gt;::</phrase><phrase role="identifier">arg4_type</phrase></computeroutput>
2604             </para>
2605             </entry><entry>
2606             <para>
2607               The type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">void</phrase><phrase role="special">*</phrase></computeroutput>.
2608             </para>
2609             </entry>
2610           </row>
2611           <row>
2612             <entry>
2613             <para>
2614               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">function_traits</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">long</phrase> <phrase role="special">(</phrase><phrase role="keyword">int</phrase><phrase role="special">,</phrase> <phrase role="keyword">long</phrase><phrase role="special">,</phrase> <phrase role="keyword">double</phrase><phrase role="special">,</phrase> <phrase role="keyword">void</phrase><phrase role="special">*)&gt;::</phrase><phrase role="identifier">arg5_type</phrase></computeroutput>
2615             </para>
2616             </entry><entry>
2617             <para>
2618               A compiler error: there is no <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">arg5_type</phrase></computeroutput>
2619               since there are only four arguments.
2620             </para>
2621             </entry>
2622           </row>
2623           <row>
2624             <entry>
2625             <para>
2626               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">function_traits</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">long</phrase> <phrase role="special">(*)(</phrase><phrase role="keyword">void</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">arity</phrase></computeroutput>
2627             </para>
2628             </entry><entry>
2629             <para>
2630               A compiler error: argument type is a <emphasis>function pointer</emphasis>,
2631               and not a <emphasis>function type</emphasis>.
2632             </para>
2633             </entry>
2634           </row>
2635         </tbody>
2636       </tgroup>
2637       </table>
2638     </section>
2639     <section id="boost_typetraits.reference.has_nothrow_assign"><indexterm type="class_name"><primary>has_nothrow_assign</primary><secondary>has_nothrow_assign</secondary></indexterm>
2640       <title><link linkend="boost_typetraits.reference.has_nothrow_assign"> has_nothrow_assign</link></title>
2641
2642 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
2643 <phrase role="keyword">struct</phrase> <phrase role="identifier">has_nothrow_assign</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
2644 </programlisting>
2645       <para>
2646         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
2647         type with a non-throwing assignment-operator then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
2648         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
2649         Type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput> must be a complete
2650         type.
2651       </para>
2652       <para>
2653         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
2654         does not support partial-specialization of class templates, then this template
2655         can not be used with function types.
2656       </para>
2657       <para>
2658         Without some (as yet unspecified) help from the compiler, <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_nothrow_assign</phrase></computeroutput>
2659         will never report that a class or struct has a non-throwing assignment-operator;
2660         this is always safe, if possibly sub-optimal. Currently (May 2005) only Visual
2661         C++ 8 has the necessary compiler support to ensure that this trait "just
2662         works".
2663       </para>
2664       <para>
2665         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
2666         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">has_nothrow_assign</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2667         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2668       </para>
2669     </section>
2670     <section id="boost_typetraits.reference.has_nothrow_constructor"><indexterm type="class_name"><primary>has_nothrow_default_constructor</primary><secondary>has_nothrow_constructor</secondary></indexterm><indexterm><primary>has_nothrow_constructor</primary><secondary>has_nothrow_default_constructor</secondary></indexterm><indexterm type="class_name"><primary>has_nothrow_constructor</primary><secondary>has_nothrow_constructor</secondary></indexterm>
2671       <title><link linkend="boost_typetraits.reference.has_nothrow_constructor">
2672       has_nothrow_constructor</link></title>
2673 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
2674 <phrase role="keyword">struct</phrase> <phrase role="identifier">has_nothrow_constructor</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
2675
2676 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
2677 <phrase role="keyword">struct</phrase> <phrase role="identifier">has_nothrow_default_constructor</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
2678 </programlisting>
2679       <para>
2680         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
2681         type with a non-throwing default-constructor then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
2682         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
2683         Type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput> must be a complete
2684         type.
2685       </para>
2686       <para>
2687         These two traits are synonyms for each other.
2688       </para>
2689       <para>
2690         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
2691         does not support partial-specialization of class templates, then this template
2692         can not be used with function types.
2693       </para>
2694       <para>
2695         Without some (as yet unspecified) help from the compiler, <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_nothrow_constructor</phrase></computeroutput>
2696         will never report that a class or struct has a non-throwing default-constructor;
2697         this is always safe, if possibly sub-optimal. Currently (May 2005) only Visual
2698         C++ 8 has the necessary compiler <link linkend="boost_typetraits.intrinsics">intrinsics</link>
2699         to ensure that this trait "just works".
2700       </para>
2701       <para>
2702         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
2703         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">has_nothrow_constructor</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2704         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2705       </para>
2706     </section>
2707     <section id="boost_typetraits.reference.has_nothrow_copy"><indexterm type="class_name"><primary>has_nothrow_copy_constructor</primary><secondary>has_nothrow_copy</secondary></indexterm><indexterm><primary>has_nothrow_copy</primary><secondary>has_nothrow_copy_constructor</secondary></indexterm><indexterm type="class_name"><primary>has_nothrow_copy</primary><secondary>has_nothrow_copy</secondary></indexterm>
2708       <title><link linkend="boost_typetraits.reference.has_nothrow_copy"> has_nothrow_copy</link></title>
2709
2710 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
2711 <phrase role="keyword">struct</phrase> <phrase role="identifier">has_nothrow_copy</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
2712
2713 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
2714 <phrase role="keyword">struct</phrase> <phrase role="identifier">has_nothrow_copy_constructor</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
2715 </programlisting>
2716       <para>
2717         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
2718         type with a non-throwing copy-constructor then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
2719         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
2720         Type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput> must be a complete
2721         type.
2722       </para>
2723       <para>
2724         These two traits are synonyms for each other.
2725       </para>
2726       <para>
2727         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
2728         does not support partial-specialization of class templates, then this template
2729         can not be used with function types.
2730       </para>
2731       <para>
2732         Without some (as yet unspecified) help from the compiler, <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_nothrow_copy</phrase></computeroutput>
2733         will never report that a class or struct has a non-throwing copy-constructor;
2734         this is always safe, if possibly sub-optimal. Currently (May 2005) only Visual
2735         C++ 8 has the necessary compiler <link linkend="boost_typetraits.intrinsics">intrinsics</link>
2736         to ensure that this trait "just works".
2737       </para>
2738       <para>
2739         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
2740         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">has_nothrow_copy</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2741         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2742       </para>
2743     </section>
2744     <section id="boost_typetraits.reference.has_nothrow_cp_cons">
2745       <title><link linkend="boost_typetraits.reference.has_nothrow_cp_cons"> has_nothrow_copy_constructor</link></title>
2746       <para>
2747         See <link linkend="boost_typetraits.reference.has_nothrow_copy">has_nothrow_copy</link>.
2748       </para>
2749     </section>
2750     <section id="boost_typetraits.reference.has_no_throw_def_cons">
2751       <title><link linkend="boost_typetraits.reference.has_no_throw_def_cons"> has_nothrow_default_constructor</link></title>
2752       <para>
2753         See <link linkend="boost_typetraits.reference.has_nothrow_constructor">has_nothrow_constructor</link>.
2754       </para>
2755     </section>
2756     <section id="boost_typetraits.reference.has_trivial_assign"><indexterm type="class_name"><primary>has_trivial_assign</primary><secondary>has_trivial_assign</secondary></indexterm>
2757       <title><link linkend="boost_typetraits.reference.has_trivial_assign"> has_trivial_assign</link></title>
2758
2759 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
2760 <phrase role="keyword">struct</phrase> <phrase role="identifier">has_trivial_assign</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
2761 </programlisting>
2762       <para>
2763         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
2764         type with a trivial assignment-operator then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
2765         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
2766       </para>
2767       <para>
2768         If a type has a trivial assignment-operator then the operator has the same
2769         effect as copying the bits of one object to the other: calls to the operator
2770         can be safely replaced with a call to <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">memcpy</phrase></computeroutput>.
2771       </para>
2772       <para>
2773         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
2774         does not support partial-specialization of class templates, then this template
2775         can not be used with function types.
2776       </para>
2777       <para>
2778         Without some (as yet unspecified) help from the compiler, has_trivial_assign
2779         will never report that a user-defined class or struct has a trivial constructor;
2780         this is always safe, if possibly sub-optimal. Currently (May 2005) only MWCW
2781         9 and Visual C++ 8 have the necessary compiler <link linkend="boost_typetraits.intrinsics">intrinsics</link>
2782         to detect user-defined classes with trivial constructors.
2783       </para>
2784       <para>
2785         <emphasis role="bold">C++ Standard Reference:</emphasis> 12.8p11.
2786       </para>
2787       <para>
2788         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
2789         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">has_trivial_assign</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2790         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2791       </para>
2792       <para>
2793         <emphasis role="bold">Examples:</emphasis>
2794       </para>
2795       <blockquote>
2796         <para>
2797           <para>
2798             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_assign</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;</phrase></computeroutput>
2799             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
2800           </para>
2801         </para>
2802       </blockquote>
2803       <blockquote>
2804         <para>
2805           <para>
2806             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_assign</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
2807           </para>
2808         </para>
2809       </blockquote>
2810       <blockquote>
2811         <para>
2812           <para>
2813             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_assign</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(*)(</phrase><phrase role="keyword">long</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
2814             that evaluates to <emphasis>true</emphasis>.
2815           </para>
2816         </para>
2817       </blockquote>
2818       <blockquote>
2819         <para>
2820           <para>
2821             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_assign</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
2822             that evaluates to <emphasis>false</emphasis>.
2823           </para>
2824         </para>
2825       </blockquote>
2826       <blockquote>
2827         <para>
2828           <para>
2829             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_assign</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
2830           </para>
2831         </para>
2832       </blockquote>
2833     </section>
2834     <section id="boost_typetraits.reference.has_trivial_constructor"><indexterm type="class_name"><primary>has_trivial_default_constructor</primary><secondary>has_trivial_constructor</secondary></indexterm><indexterm><primary>has_trivial_constructor</primary><secondary>has_trivial_default_constructor</secondary></indexterm>
2835       <title><link linkend="boost_typetraits.reference.has_trivial_constructor">
2836       has_trivial_constructor</link></title>
2837 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
2838 <phrase role="keyword">struct</phrase> <phrase role="identifier">has_trivial_constructor</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
2839
2840 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
2841 <phrase role="keyword">struct</phrase> <phrase role="identifier">has_trivial_default_constructor</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
2842 </programlisting>
2843       <para>
2844         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
2845         type with a trivial default-constructor then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
2846         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
2847       </para>
2848       <para>
2849         These two traits are synonyms for each other.
2850       </para>
2851       <para>
2852         If a type has a trivial default-constructor then the constructor have no
2853         effect: calls to the constructor can be safely omitted. Note that using meta-programming
2854         to omit a call to a single trivial-constructor call is of no benefit whatsoever.
2855         However, if loops and/or exception handling code can also be omitted, then
2856         some benefit in terms of code size and speed can be obtained.
2857       </para>
2858       <para>
2859         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
2860         does not support partial-specialization of class templates, then this template
2861         can not be used with function types.
2862       </para>
2863       <para>
2864         Without some (as yet unspecified) help from the compiler, has_trivial_constructor
2865         will never report that a user-defined class or struct has a trivial constructor;
2866         this is always safe, if possibly sub-optimal. Currently (May 2005) only MWCW
2867         9 and Visual C++ 8 have the necessary compiler <link linkend="boost_typetraits.intrinsics">intrinsics</link>
2868         to detect user-defined classes with trivial constructors.
2869       </para>
2870       <para>
2871         <emphasis role="bold">C++ Standard Reference:</emphasis> 12.1p6.
2872       </para>
2873       <para>
2874         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
2875         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">has_trivial_constructor</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2876         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2877       </para>
2878       <para>
2879         <emphasis role="bold">Examples:</emphasis>
2880       </para>
2881       <blockquote>
2882         <para>
2883           <para>
2884             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_constructor</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;</phrase></computeroutput> inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
2885           </para>
2886         </para>
2887       </blockquote>
2888       <blockquote>
2889         <para>
2890           <para>
2891             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_constructor</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
2892             is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
2893           </para>
2894         </para>
2895       </blockquote>
2896       <blockquote>
2897         <para>
2898           <para>
2899             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_constructor</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(*)(</phrase><phrase role="keyword">long</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
2900             is an integral constant expression that evaluates to <emphasis>true</emphasis>.
2901           </para>
2902         </para>
2903       </blockquote>
2904       <blockquote>
2905         <para>
2906           <para>
2907             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_constructor</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
2908             is an integral constant expression that evaluates to <emphasis>false</emphasis>.
2909           </para>
2910         </para>
2911       </blockquote>
2912       <blockquote>
2913         <para>
2914           <para>
2915             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_constructor</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput>
2916             is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
2917           </para>
2918         </para>
2919       </blockquote>
2920     </section>
2921     <section id="boost_typetraits.reference.has_trivial_copy"><indexterm type="class_name"><primary>has_trivial_copy_constructor</primary><secondary>has_trivial_copy</secondary></indexterm><indexterm><primary>has_trivial_copy</primary><secondary>has_trivial_copy_constructor</secondary></indexterm><indexterm type="class_name"><primary>has_trivial_copy</primary><secondary>has_trivial_copy</secondary></indexterm>
2922       <title><link linkend="boost_typetraits.reference.has_trivial_copy"> has_trivial_copy</link></title>
2923
2924 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
2925 <phrase role="keyword">struct</phrase> <phrase role="identifier">has_trivial_copy</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
2926
2927 <phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
2928 <phrase role="keyword">struct</phrase> <phrase role="identifier">has_trivial_copy_constructor</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
2929 </programlisting>
2930       <para>
2931         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
2932         type with a trivial copy-constructor then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
2933         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
2934       </para>
2935       <para>
2936         These two traits are synonyms for each other.
2937       </para>
2938       <para>
2939         If a type has a trivial copy-constructor then the constructor has the same
2940         effect as copying the bits of one object to the other: calls to the constructor
2941         can be safely replaced with a call to <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">memcpy</phrase></computeroutput>.
2942       </para>
2943       <para>
2944         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
2945         does not support partial-specialization of class templates, then this template
2946         can not be used with function types.
2947       </para>
2948       <para>
2949         Without some (as yet unspecified) help from the compiler, has_trivial_copy
2950         will never report that a user-defined class or struct has a trivial constructor;
2951         this is always safe, if possibly sub-optimal. Currently (May 2005) only MWCW
2952         9 and Visual C++ 8 have the necessary compiler <link linkend="boost_typetraits.intrinsics">intrinsics</link>
2953         to detect user-defined classes with trivial constructors.
2954       </para>
2955       <para>
2956         <emphasis role="bold">C++ Standard Reference:</emphasis> 12.8p6.
2957       </para>
2958       <para>
2959         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
2960         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">has_trivial_copy</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2961         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
2962       </para>
2963       <para>
2964         <emphasis role="bold">Examples:</emphasis>
2965       </para>
2966       <blockquote>
2967         <para>
2968           <para>
2969             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_copy</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;</phrase></computeroutput>
2970             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
2971           </para>
2972         </para>
2973       </blockquote>
2974       <blockquote>
2975         <para>
2976           <para>
2977             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_copy</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
2978           </para>
2979         </para>
2980       </blockquote>
2981       <blockquote>
2982         <para>
2983           <para>
2984             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_copy</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(*)(</phrase><phrase role="keyword">long</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
2985             that evaluates to <emphasis>true</emphasis>.
2986           </para>
2987         </para>
2988       </blockquote>
2989       <blockquote>
2990         <para>
2991           <para>
2992             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_copy</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
2993             that evaluates to <emphasis>false</emphasis>.
2994           </para>
2995         </para>
2996       </blockquote>
2997       <blockquote>
2998         <para>
2999           <para>
3000             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_copy</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
3001           </para>
3002         </para>
3003       </blockquote>
3004     </section>
3005     <section id="boost_typetraits.reference.has_trivial_cp_cons">
3006       <title><link linkend="boost_typetraits.reference.has_trivial_cp_cons"> has_trivial_copy_constructor</link></title>
3007       <para>
3008         See <link linkend="boost_typetraits.reference.has_trivial_copy">has_trivial_copy</link>.
3009       </para>
3010     </section>
3011     <section id="boost_typetraits.reference.has_trivial_def_cons">
3012       <title><link linkend="boost_typetraits.reference.has_trivial_def_cons"> has_trivial_default_constructor</link></title>
3013       <para>
3014         See <link linkend="boost_typetraits.reference.has_trivial_constructor">has_trivial_constructor</link>.
3015       </para>
3016     </section>
3017     <section id="boost_typetraits.reference.has_trivial_destructor"><indexterm type="class_name"><primary>has_trivial_destructor</primary><secondary>has_trivial_destructor</secondary></indexterm>
3018       <title><link linkend="boost_typetraits.reference.has_trivial_destructor"> has_trivial_destructor</link></title>
3019
3020 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
3021 <phrase role="keyword">struct</phrase> <phrase role="identifier">has_trivial_destructor</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
3022 </programlisting>
3023       <para>
3024         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
3025         type with a trivial destructor then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
3026         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
3027       </para>
3028       <para>
3029         If a type has a trivial destructor then the destructor has no effect: calls
3030         to the destructor can be safely omitted. Note that using meta-programming
3031         to omit a call to a single trivial-constructor call is of no benefit whatsoever.
3032         However, if loops and/or exception handling code can also be omitted, then
3033         some benefit in terms of code size and speed can be obtained.
3034       </para>
3035       <para>
3036         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
3037         does not support partial-specialization of class templates, then this template
3038         can not be used with function types.
3039       </para>
3040       <para>
3041         Without some (as yet unspecified) help from the compiler, has_trivial_destructor
3042         will never report that a user-defined class or struct has a trivial destructor;
3043         this is always safe, if possibly sub-optimal. Currently (May 2005) only MWCW
3044         9 and Visual C++ 8 have the necessary compiler <link linkend="boost_typetraits.intrinsics">intrinsics</link>
3045         to detect user-defined classes with trivial constructors.
3046       </para>
3047       <para>
3048         <emphasis role="bold">C++ Standard Reference:</emphasis> 12.4p3.
3049       </para>
3050       <para>
3051         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
3052         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">has_trivial_destructor</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3053         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3054       </para>
3055       <para>
3056         <emphasis role="bold">Examples:</emphasis>
3057       </para>
3058       <blockquote>
3059         <para>
3060           <para>
3061             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_destructor</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;</phrase></computeroutput> inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
3062           </para>
3063         </para>
3064       </blockquote>
3065       <blockquote>
3066         <para>
3067           <para>
3068             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_destructor</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
3069             is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
3070           </para>
3071         </para>
3072       </blockquote>
3073       <blockquote>
3074         <para>
3075           <para>
3076             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_destructor</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(*)(</phrase><phrase role="keyword">long</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
3077             is an integral constant expression that evaluates to <emphasis>true</emphasis>.
3078           </para>
3079         </para>
3080       </blockquote>
3081       <blockquote>
3082         <para>
3083           <para>
3084             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_destructor</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
3085             is an integral constant expression that evaluates to <emphasis>false</emphasis>.
3086           </para>
3087         </para>
3088       </blockquote>
3089       <blockquote>
3090         <para>
3091           <para>
3092             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">has_trivial_destructor</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput>
3093             is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
3094           </para>
3095         </para>
3096       </blockquote>
3097     </section>
3098     <section id="boost_typetraits.reference.has_virtual_destructor"><indexterm type="class_name"><primary>has_virtual_destructor</primary><secondary>has_virtual_destructor</secondary></indexterm>
3099       <title><link linkend="boost_typetraits.reference.has_virtual_destructor"> has_virtual_destructor</link></title>
3100
3101 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
3102 <phrase role="keyword">struct</phrase> <phrase role="identifier">has_virtual_destructor</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
3103 </programlisting>
3104       <para>
3105         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
3106         type with a virtual destructor then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
3107         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
3108       </para>
3109       <para>
3110         <emphasis role="bold">Compiler Compatibility:</emphasis> This trait is provided
3111         for completeness, since it's part of the Technical Report on C++ Library
3112         Extensions. However, there is currently no way to portably implement this
3113         trait. The default version provided always inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>,
3114         and has to be explicitly specialized for types with virtual destructors unless
3115         the compiler used has compiler <link linkend="boost_typetraits.intrinsics">intrinsics</link>
3116         that enable the trait to do the right thing: currently (May 2005) only Visual
3117         C++ 8 and GCC-4.3 have the necessary <link linkend="boost_typetraits.intrinsics">intrinsics</link>.
3118       </para>
3119       <para>
3120         <emphasis role="bold">C++ Standard Reference:</emphasis> 12.4.
3121       </para>
3122       <para>
3123         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
3124         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">has_virtual_destructor</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3125         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3126       </para>
3127     </section>
3128     <section id="boost_typetraits.reference.integral_constant"><indexterm type="typedef_name"><primary>value_type</primary><secondary>integral_constant</secondary></indexterm><indexterm><primary>integral_constant</primary><secondary>value_type</secondary></indexterm><indexterm type="typedef_name"><primary>true_type</primary><secondary>integral_constant</secondary></indexterm><indexterm><primary>integral_constant</primary><secondary>true_type</secondary></indexterm><indexterm type="class_name"><primary>integral_constant</primary><secondary>integral_constant</secondary></indexterm><indexterm type="typedef_name"><primary>false_type</primary><secondary>integral_constant</secondary></indexterm><indexterm><primary>integral_constant</primary><secondary>false_type</secondary></indexterm>
3129       <title><link linkend="boost_typetraits.reference.integral_constant"> integral_constant</link></title>
3130
3131 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">,</phrase> <phrase role="identifier">T</phrase> <phrase role="identifier">val</phrase><phrase role="special">&gt;</phrase>
3132 <phrase role="keyword">struct</phrase> <phrase role="identifier">integral_constant</phrase>
3133 <phrase role="special">{</phrase>
3134    <phrase role="keyword">typedef</phrase> <phrase role="identifier">integral_constant</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">,</phrase> <phrase role="identifier">val</phrase><phrase role="special">&gt;</phrase>  <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
3135    <phrase role="keyword">typedef</phrase> <phrase role="identifier">T</phrase>                          <phrase role="identifier">value_type</phrase><phrase role="special">;</phrase>
3136    <phrase role="keyword">static</phrase> <phrase role="keyword">const</phrase> <phrase role="identifier">T</phrase> <phrase role="identifier">value</phrase> <phrase role="special">=</phrase> <phrase role="identifier">val</phrase><phrase role="special">;</phrase>
3137 <phrase role="special">};</phrase>
3138
3139 <phrase role="keyword">typedef</phrase> <phrase role="identifier">integral_constant</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">bool</phrase><phrase role="special">,</phrase> <phrase role="keyword">true</phrase><phrase role="special">&gt;</phrase>  <phrase role="identifier">true_type</phrase><phrase role="special">;</phrase>
3140 <phrase role="keyword">typedef</phrase> <phrase role="identifier">integral_constant</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">bool</phrase><phrase role="special">,</phrase> <phrase role="keyword">false</phrase><phrase role="special">&gt;</phrase> <phrase role="identifier">false_type</phrase><phrase role="special">;</phrase>
3141 </programlisting>
3142       <para>
3143         Class template <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">integral_constant</phrase></computeroutput>
3144         is the common base class for all the value-based type traits. The two typedef's
3145         <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">true_type</phrase></computeroutput> and <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">false_type</phrase></computeroutput> are provided for convenience:
3146         most of the value traits are Boolean properties and so will inherit from
3147         one of these.
3148       </para>
3149     </section>
3150     <section id="boost_typetraits.reference.integral_promotion"><indexterm type="class_name"><primary>integral_promotion</primary><secondary>integral_promotion</secondary></indexterm>
3151       <title><link linkend="boost_typetraits.reference.integral_promotion"> integral_promotion</link></title>
3152
3153 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
3154 <phrase role="keyword">struct</phrase> <phrase role="identifier">integral_promotion</phrase>
3155 <phrase role="special">{</phrase>
3156    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
3157 <phrase role="special">};</phrase>
3158 </programlisting>
3159       <para>
3160         <emphasis role="bold">type:</emphasis> If integral promotion can be applied
3161         to an rvalue of type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>, then
3162         applies integral promotion to <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>
3163         and keeps cv-qualifiers of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>,
3164         otherwise leaves <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput> unchanged.
3165       </para>
3166       <para>
3167         <emphasis role="bold">C++ Standard Reference:</emphasis> 4.5 except 4.5/3
3168         (integral bit-field).
3169       </para>
3170       <para>
3171         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
3172         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">integral_promotion</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3173         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3174       </para>
3175       <table frame="all"> <title>Examples</title>
3176       <tgroup cols="2">
3177         <thead>
3178           <row>
3179             <entry>
3180             <para>
3181               Expression
3182             </para>
3183             </entry><entry>
3184             <para>
3185               Result Type
3186             </para>
3187             </entry>
3188           </row>
3189         </thead>
3190         <tbody>
3191           <row>
3192             <entry>
3193             <para>
3194               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">integral_promotion</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">short</phrase>
3195               <phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
3196             </para>
3197             </entry><entry>
3198             <para>
3199               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase></computeroutput>
3200             </para>
3201             </entry>
3202           </row>
3203           <row>
3204             <entry>
3205             <para>
3206               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">integral_promotion</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">short</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
3207             </para>
3208             </entry><entry>
3209             <para>
3210               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">short</phrase><phrase role="special">&amp;</phrase></computeroutput>
3211             </para>
3212             </entry>
3213           </row>
3214           <row>
3215             <entry>
3216             <para>
3217               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">integral_promotion</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">enum</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">float_round_style</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
3218             </para>
3219             </entry><entry>
3220             <para>
3221               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase></computeroutput>
3222             </para>
3223             </entry>
3224           </row>
3225         </tbody>
3226       </tgroup>
3227       </table>
3228     </section>
3229     <section id="boost_typetraits.reference.is_abstract"><indexterm type="class_name"><primary>is_abstract</primary><secondary>is_abstract</secondary></indexterm>
3230       <title><link linkend="boost_typetraits.reference.is_abstract"> is_abstract</link></title>
3231
3232 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
3233 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_abstract</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
3234 </programlisting>
3235       <para>
3236         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
3237         abstract type then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
3238         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
3239       </para>
3240       <para>
3241         <emphasis role="bold">C++ Standard Reference:</emphasis> 10.3.
3242       </para>
3243       <para>
3244         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
3245         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_abstract</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3246         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3247       </para>
3248       <para>
3249         <emphasis role="bold">Compiler Compatibility:</emphasis> The compiler must
3250         support DR337 (as of April 2005: GCC 3.4, VC++ 7.1 (and later), Intel C++
3251         7 (and later), and Comeau 4.3.2). Otherwise behaves the same as <link linkend="boost_typetraits.reference.is_polymorphic">is_polymorphic</link>;
3252         this is the "safe fallback position" for which polymorphic types
3253         are always regarded as potentially abstract. The macro BOOST_NO_IS_ABSTRACT
3254         is used to signify that the implementation is buggy, users should check for
3255         this in their own code if the "safe fallback" is not suitable for
3256         their particular use-case.
3257       </para>
3258       <para>
3259         <emphasis role="bold">Examples:</emphasis>
3260       </para>
3261       <blockquote>
3262         <para>
3263           <para>
3264             Given: <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">class</phrase> <phrase role="identifier">abc</phrase><phrase role="special">{</phrase> <phrase role="keyword">virtual</phrase> <phrase role="special">~</phrase><phrase role="identifier">abc</phrase><phrase role="special">()</phrase> <phrase role="special">=</phrase> <phrase role="number">0</phrase><phrase role="special">;</phrase> <phrase role="special">};</phrase></computeroutput>
3265           </para>
3266         </para>
3267       </blockquote>
3268       <blockquote>
3269         <para>
3270           <para>
3271             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_abstract</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">abc</phrase><phrase role="special">&gt;</phrase></computeroutput>
3272             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
3273           </para>
3274         </para>
3275       </blockquote>
3276       <blockquote>
3277         <para>
3278           <para>
3279             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_abstract</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">abc</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
3280           </para>
3281         </para>
3282       </blockquote>
3283       <blockquote>
3284         <para>
3285           <para>
3286             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_abstract</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">abc</phrase> <phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
3287             is an integral constant expression that evaluates to <emphasis>true</emphasis>.
3288           </para>
3289         </para>
3290       </blockquote>
3291       <blockquote>
3292         <para>
3293           <para>
3294             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_abstract</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
3295           </para>
3296         </para>
3297       </blockquote>
3298     </section>
3299     <section id="boost_typetraits.reference.is_arithmetic"><indexterm type="class_name"><primary>is_arithmetic</primary><secondary>is_arithmetic</secondary></indexterm>
3300       <title><link linkend="boost_typetraits.reference.is_arithmetic"> is_arithmetic</link></title>
3301
3302 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
3303 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_arithmetic</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
3304 </programlisting>
3305       <para>
3306         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
3307         arithmetic type then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
3308         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
3309         Arithmetic types include integral and floating point types (see also <link linkend="boost_typetraits.reference.is_integral">is_integral</link> and
3310         <link linkend="boost_typetraits.reference.is_floating_point">is_floating_point</link>).
3311       </para>
3312       <para>
3313         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.1p8.
3314       </para>
3315       <para>
3316         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
3317         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_arithmetic</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3318         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3319       </para>
3320       <para>
3321         <emphasis role="bold">Examples:</emphasis>
3322       </para>
3323       <blockquote>
3324         <para>
3325           <para>
3326             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_arithmetic</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;</phrase></computeroutput>
3327             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
3328           </para>
3329         </para>
3330       </blockquote>
3331       <blockquote>
3332         <para>
3333           <para>
3334             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_arithmetic</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
3335           </para>
3336         </para>
3337       </blockquote>
3338       <blockquote>
3339         <para>
3340           <para>
3341             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_arithmetic</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">double</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
3342             that evaluates to <emphasis>true</emphasis>.
3343           </para>
3344         </para>
3345       </blockquote>
3346       <blockquote>
3347         <para>
3348           <para>
3349             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_arithmetic</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
3350           </para>
3351         </para>
3352       </blockquote>
3353     </section>
3354     <section id="boost_typetraits.reference.is_array"><indexterm type="class_name"><primary>is_array</primary><secondary>is_array</secondary></indexterm>
3355       <title><link linkend="boost_typetraits.reference.is_array"> is_array</link></title>
3356
3357 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
3358 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_array</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
3359 </programlisting>
3360       <para>
3361         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
3362         array type then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
3363         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
3364       </para>
3365       <para>
3366         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.2 and 8.3.4.
3367       </para>
3368       <para>
3369         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
3370         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_array</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3371         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3372       </para>
3373       <para>
3374         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
3375         does not support partial-specialization of class templates, then this template
3376         can give the wrong result with function types.
3377       </para>
3378       <para>
3379         <emphasis role="bold">Examples:</emphasis>
3380       </para>
3381       <blockquote>
3382         <para>
3383           <para>
3384             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_array</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">[</phrase><phrase role="number">2</phrase><phrase role="special">]&gt;</phrase></computeroutput> inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
3385           </para>
3386         </para>
3387       </blockquote>
3388       <blockquote>
3389         <para>
3390           <para>
3391             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_array</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase><phrase role="special">[</phrase><phrase role="number">2</phrase><phrase role="special">][</phrase><phrase role="number">3</phrase><phrase role="special">]&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
3392             is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
3393           </para>
3394         </para>
3395       </blockquote>
3396       <blockquote>
3397         <para>
3398           <para>
3399             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_array</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">double</phrase><phrase role="special">[]&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
3400             that evaluates to <emphasis>true</emphasis>.
3401           </para>
3402         </para>
3403       </blockquote>
3404       <blockquote>
3405         <para>
3406           <para>
3407             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_array</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
3408           </para>
3409         </para>
3410       </blockquote>
3411     </section>
3412     <section id="boost_typetraits.reference.is_base_of"><indexterm type="class_name"><primary>is_base_of</primary><secondary>is_base_of</secondary></indexterm>
3413       <title><link linkend="boost_typetraits.reference.is_base_of"> is_base_of</link></title>
3414
3415 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">Base</phrase><phrase role="special">,</phrase> <phrase role="keyword">class</phrase> <phrase role="identifier">Derived</phrase><phrase role="special">&gt;</phrase>
3416 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_base_of</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
3417 </programlisting>
3418       <para>
3419         <emphasis role="bold">Inherits:</emphasis> If Base is base class of type
3420         Derived or if both types are the same then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
3421         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
3422       </para>
3423       <para>
3424         This template will detect non-public base classes, and ambiguous base classes.
3425       </para>
3426       <para>
3427         Note that <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_base_of</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">X</phrase><phrase role="special">,</phrase><phrase role="identifier">X</phrase><phrase role="special">&gt;</phrase></computeroutput> will always inherit from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>.
3428         <emphasis role="bold">This is the case even if <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">X</phrase></computeroutput>
3429         is not a class type</emphasis>. This is a change in behaviour from Boost-1.33
3430         in order to track the Technical Report on C++ Library Extensions.
3431       </para>
3432       <para>
3433         Types <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">Base</phrase></computeroutput> and <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">Derived</phrase></computeroutput> must not be incomplete types.
3434       </para>
3435       <para>
3436         <emphasis role="bold">C++ Standard Reference:</emphasis> 10.
3437       </para>
3438       <para>
3439         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
3440         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_base_of</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3441         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3442       </para>
3443       <para>
3444         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
3445         does not support partial-specialization of class templates, then this template
3446         can not be used with function types. There are some older compilers which
3447         will produce compiler errors if <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">Base</phrase></computeroutput>
3448         is a private base class of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">Derived</phrase></computeroutput>,
3449         or if <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">Base</phrase></computeroutput> is an ambiguous
3450         base of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">Derived</phrase></computeroutput>. These compilers
3451         include Borland C++, older versions of Sun Forte C++, Digital Mars C++, and
3452         older versions of EDG based compilers.
3453       </para>
3454       <para>
3455         <emphasis role="bold">Examples:</emphasis>
3456       </para>
3457       <blockquote>
3458         <para>
3459           <para>
3460             Given: <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="keyword">class</phrase> <phrase role="identifier">Base</phrase><phrase role="special">{};</phrase> <phrase role="keyword">class</phrase> <phrase role="identifier">Derived</phrase> <phrase role="special">:</phrase>
3461             <phrase role="keyword">public</phrase> <phrase role="identifier">Base</phrase><phrase role="special">{};</phrase></computeroutput>
3462           </para>
3463         </para>
3464       </blockquote>
3465       <blockquote>
3466         <para>
3467           <para>
3468             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_base_of</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">Base</phrase><phrase role="special">,</phrase> <phrase role="identifier">Derived</phrase><phrase role="special">&gt;</phrase></computeroutput>
3469             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
3470           </para>
3471         </para>
3472       </blockquote>
3473       <blockquote>
3474         <para>
3475           <para>
3476             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_base_of</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">Base</phrase><phrase role="special">,</phrase> <phrase role="identifier">Derived</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
3477           </para>
3478         </para>
3479       </blockquote>
3480       <blockquote>
3481         <para>
3482           <para>
3483             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_base_of</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">Base</phrase><phrase role="special">,</phrase> <phrase role="identifier">Derived</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
3484             that evaluates to <emphasis>true</emphasis>.
3485           </para>
3486         </para>
3487       </blockquote>
3488       <blockquote>
3489         <para>
3490           <para>
3491             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_base_of</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">Base</phrase><phrase role="special">,</phrase> <phrase role="identifier">Derived</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
3492             that evaluates to <emphasis>true</emphasis>.
3493           </para>
3494         </para>
3495       </blockquote>
3496       <blockquote>
3497         <para>
3498           <para>
3499             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_base_of</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">Base</phrase><phrase role="special">,</phrase> <phrase role="identifier">Base</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
3500             that evaluates to <emphasis>true</emphasis>: a class is regarded as it's
3501             own base.
3502           </para>
3503         </para>
3504       </blockquote>
3505       <blockquote>
3506         <para>
3507           <para>
3508             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_base_of</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
3509           </para>
3510         </para>
3511       </blockquote>
3512     </section>
3513     <section id="boost_typetraits.reference.is_class"><indexterm type="class_name"><primary>is_class</primary><secondary>is_class</secondary></indexterm>
3514       <title><link linkend="boost_typetraits.reference.is_class"> is_class</link></title>
3515
3516 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
3517 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_class</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
3518 </programlisting>
3519       <para>
3520         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
3521         class type then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
3522         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
3523       </para>
3524       <para>
3525         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.2 and 9.2.
3526       </para>
3527       <para>
3528         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
3529         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_class</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3530         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3531       </para>
3532       <para>
3533         <emphasis role="bold">Compiler Compatibility:</emphasis> Without (some as
3534         yet unspecified) help from the compiler, we cannot distinguish between union
3535         and class types, as a result this type will erroneously inherit from <link linkend="boost_typetraits.reference.integral_constant">true_type</link> for
3536         union types. See also <link linkend="boost_typetraits.reference.is_union">is_union</link>.
3537         Currently (May 2005) only Visual C++ 8 has the necessary compiler <link linkend="boost_typetraits.intrinsics">intrinsics</link>
3538         to correctly identify union types, and therefore make is_class function correctly.
3539       </para>
3540       <para>
3541         <emphasis role="bold">Examples:</emphasis>
3542       </para>
3543       <blockquote>
3544         <para>
3545           <para>
3546             Given: <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">class</phrase> <phrase role="identifier">MyClass</phrase><phrase role="special">;</phrase></computeroutput> then:
3547           </para>
3548         </para>
3549       </blockquote>
3550       <blockquote>
3551         <para>
3552           <para>
3553             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_class</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">&gt;</phrase></computeroutput>
3554             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
3555           </para>
3556         </para>
3557       </blockquote>
3558       <blockquote>
3559         <para>
3560           <para>
3561             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_class</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">MyClass</phrase> <phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
3562             is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
3563           </para>
3564         </para>
3565       </blockquote>
3566       <blockquote>
3567         <para>
3568           <para>
3569             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_class</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
3570             that evaluates to <emphasis>true</emphasis>.
3571           </para>
3572         </para>
3573       </blockquote>
3574       <blockquote>
3575         <para>
3576           <para>
3577             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_class</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
3578             that evaluates to <emphasis>false</emphasis>.
3579           </para>
3580         </para>
3581       </blockquote>
3582       <blockquote>
3583         <para>
3584           <para>
3585             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_class</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
3586             that evaluates to <emphasis>false</emphasis>.
3587           </para>
3588         </para>
3589       </blockquote>
3590       <blockquote>
3591         <para>
3592           <para>
3593             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_class</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
3594           </para>
3595         </para>
3596       </blockquote>
3597     </section>
3598     <section id="boost_typetraits.reference.is_complex"><indexterm type="class_name"><primary>is_complex</primary><secondary>is_complex</secondary></indexterm>
3599       <title><link linkend="boost_typetraits.reference.is_complex"> is_complex</link></title>
3600
3601 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
3602 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_complex</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
3603 </programlisting>
3604       <para>
3605         <emphasis role="bold">Inherits:</emphasis> If <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>
3606         is a complex number type then true (of type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">complex</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">U</phrase><phrase role="special">&gt;</phrase></computeroutput>
3607         for some type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">U</phrase></computeroutput>), otherwise
3608         false.
3609       </para>
3610       <para>
3611         <emphasis role="bold">C++ Standard Reference:</emphasis> 26.2.
3612       </para>
3613       <para>
3614         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
3615         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_complex</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3616         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3617       </para>
3618     </section>
3619     <section id="boost_typetraits.reference.is_compound"><indexterm type="class_name"><primary>is_compound</primary><secondary>is_compound</secondary></indexterm>
3620       <title><link linkend="boost_typetraits.reference.is_compound"> is_compound</link></title>
3621
3622 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
3623 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_compound</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
3624 </programlisting>
3625       <para>
3626         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
3627         compound type then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
3628         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
3629         Any type that is not a fundamental type is a compound type (see also <link linkend="boost_typetraits.reference.is_fundamental">is_fundamental</link>).
3630       </para>
3631       <para>
3632         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.2.
3633       </para>
3634       <para>
3635         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
3636         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_compound</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3637         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3638       </para>
3639       <para>
3640         <emphasis role="bold">Examples:</emphasis>
3641       </para>
3642       <blockquote>
3643         <para>
3644           <para>
3645             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_compound</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">&gt;</phrase></computeroutput>
3646             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
3647           </para>
3648         </para>
3649       </blockquote>
3650       <blockquote>
3651         <para>
3652           <para>
3653             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_compound</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">MyEnum</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
3654           </para>
3655         </para>
3656       </blockquote>
3657       <blockquote>
3658         <para>
3659           <para>
3660             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_compound</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
3661             that evaluates to <emphasis>true</emphasis>.
3662           </para>
3663         </para>
3664       </blockquote>
3665       <blockquote>
3666         <para>
3667           <para>
3668             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_compound</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
3669             that evaluates to <emphasis>true</emphasis>.
3670           </para>
3671         </para>
3672       </blockquote>
3673       <blockquote>
3674         <para>
3675           <para>
3676             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_compound</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
3677             that evaluates to <emphasis>false</emphasis>.
3678           </para>
3679         </para>
3680       </blockquote>
3681       <blockquote>
3682         <para>
3683           <para>
3684             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_compound</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
3685           </para>
3686         </para>
3687       </blockquote>
3688     </section>
3689     <section id="boost_typetraits.reference.is_const"><indexterm type="class_name"><primary>is_const</primary><secondary>is_const</secondary></indexterm>
3690       <title><link linkend="boost_typetraits.reference.is_const"> is_const</link></title>
3691
3692 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
3693 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_const</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
3694 </programlisting>
3695       <para>
3696         <emphasis role="bold">Inherits:</emphasis> If T is a (top level) const-qualified
3697         type then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
3698         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
3699       </para>
3700       <para>
3701         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.3.
3702       </para>
3703       <para>
3704         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
3705         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_const</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3706         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3707       </para>
3708       <para>
3709         <emphasis role="bold">Examples:</emphasis>
3710       </para>
3711       <blockquote>
3712         <para>
3713           <para>
3714             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_const</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">&gt;</phrase></computeroutput> inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
3715           </para>
3716         </para>
3717       </blockquote>
3718       <blockquote>
3719         <para>
3720           <para>
3721             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_const</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase> <phrase role="keyword">volatile</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
3722           </para>
3723         </para>
3724       </blockquote>
3725       <blockquote>
3726         <para>
3727           <para>
3728             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_const</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">*</phrase> <phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
3729             that evaluates to <emphasis>true</emphasis>.
3730           </para>
3731         </para>
3732       </blockquote>
3733       <blockquote>
3734         <para>
3735           <para>
3736             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_const</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
3737             is an integral constant expression that evaluates to <emphasis>false</emphasis>:
3738             the const-qualifier is not at the top level in this case.
3739           </para>
3740         </para>
3741       </blockquote>
3742       <blockquote>
3743         <para>
3744           <para>
3745             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_const</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
3746             is an integral constant expression that evaluates to <emphasis>false</emphasis>:
3747             the const-qualifier is not at the top level in this case.
3748           </para>
3749         </para>
3750       </blockquote>
3751       <blockquote>
3752         <para>
3753           <para>
3754             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_const</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
3755             that evaluates to <emphasis>false</emphasis>.
3756           </para>
3757         </para>
3758       </blockquote>
3759       <blockquote>
3760         <para>
3761           <para>
3762             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_const</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
3763           </para>
3764         </para>
3765       </blockquote>
3766     </section>
3767     <section id="boost_typetraits.reference.is_convertible"><indexterm type="class_name"><primary>is_convertible</primary><secondary>is_convertible</secondary></indexterm>
3768       <title><link linkend="boost_typetraits.reference.is_convertible"> is_convertible</link></title>
3769
3770 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">From</phrase><phrase role="special">,</phrase> <phrase role="keyword">class</phrase> <phrase role="identifier">To</phrase><phrase role="special">&gt;</phrase>
3771 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_convertible</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
3772 </programlisting>
3773       <para>
3774         <emphasis role="bold">Inherits:</emphasis> If an imaginary lvalue of type
3775         <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">From</phrase></computeroutput> is convertible to type
3776         <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">To</phrase></computeroutput> then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
3777         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
3778       </para>
3779       <para>
3780         Type From must not be an incomplete type.
3781       </para>
3782       <para>
3783         Type To must not be an incomplete, or function type.
3784       </para>
3785       <para>
3786         No types are considered to be convertible to array types or abstract-class
3787         types.
3788       </para>
3789       <para>
3790         This template can not detect whether a converting-constructor is <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">public</phrase></computeroutput> or not: if type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">To</phrase></computeroutput>
3791         has a <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">private</phrase></computeroutput> converting constructor
3792         from type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">From</phrase></computeroutput> then instantiating
3793         <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_convertible</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">From</phrase><phrase role="special">,</phrase> <phrase role="identifier">To</phrase><phrase role="special">&gt;</phrase></computeroutput>
3794         will produce a compiler error. For this reason <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_convertible</phrase></computeroutput>
3795         can not be used to determine whether a type has a <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">public</phrase></computeroutput>
3796         copy-constructor or not.
3797       </para>
3798       <para>
3799         This template will also produce compiler errors if the conversion is ambiguous,
3800         for example:
3801       </para>
3802
3803 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">struct</phrase> <phrase role="identifier">A</phrase> <phrase role="special">{};</phrase>
3804 <phrase role="keyword">struct</phrase> <phrase role="identifier">B</phrase> <phrase role="special">:</phrase> <phrase role="identifier">A</phrase> <phrase role="special">{};</phrase>
3805 <phrase role="keyword">struct</phrase> <phrase role="identifier">C</phrase> <phrase role="special">:</phrase> <phrase role="identifier">A</phrase> <phrase role="special">{};</phrase>
3806 <phrase role="keyword">struct</phrase> <phrase role="identifier">D</phrase> <phrase role="special">:</phrase> <phrase role="identifier">B</phrase><phrase role="special">,</phrase> <phrase role="identifier">C</phrase> <phrase role="special">{};</phrase>
3807 <phrase role="comment">// This produces a compiler error, the conversion is ambiguous:
3808 </phrase><phrase role="keyword">bool</phrase> <phrase role="keyword">const</phrase> <phrase role="identifier">y</phrase> <phrase role="special">=</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">is_convertible</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">D</phrase><phrase role="special">*,</phrase><phrase role="identifier">A</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">value</phrase><phrase role="special">;</phrase>
3809 </programlisting>
3810       <para>
3811         <emphasis role="bold">C++ Standard Reference:</emphasis> 4 and 8.5.
3812       </para>
3813       <para>
3814         <emphasis role="bold">Compiler Compatibility:</emphasis> This template is
3815         currently broken with Borland C++ Builder 5 (and earlier), for constructor-based
3816         conversions, and for the Metrowerks 7 (and earlier) compiler in all cases.
3817         If the compiler does not support <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.is_abstract">is_abstract</link></computeroutput>,
3818         then the template parameter <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">To</phrase></computeroutput>
3819         must not be an abstract type.
3820       </para>
3821       <para>
3822         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
3823         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_convertible</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3824         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3825       </para>
3826       <para>
3827         <emphasis role="bold">Examples:</emphasis>
3828       </para>
3829       <blockquote>
3830         <para>
3831           <para>
3832             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_convertible</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">,</phrase> <phrase role="keyword">double</phrase><phrase role="special">&gt;</phrase></computeroutput>
3833             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
3834           </para>
3835         </para>
3836       </blockquote>
3837       <blockquote>
3838         <para>
3839           <para>
3840             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_convertible</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">const</phrase> <phrase role="keyword">int</phrase><phrase role="special">,</phrase> <phrase role="keyword">double</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
3841             is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
3842           </para>
3843         </para>
3844       </blockquote>
3845       <blockquote>
3846         <para>
3847           <para>
3848             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_convertible</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">*</phrase> <phrase role="keyword">const</phrase><phrase role="special">,</phrase> <phrase role="keyword">int</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
3849             that evaluates to <emphasis>true</emphasis>.
3850           </para>
3851         </para>
3852       </blockquote>
3853       <blockquote>
3854         <para>
3855           <para>
3856             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_convertible</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">*,</phrase> <phrase role="keyword">int</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
3857             is an integral constant expression that evaluates to <emphasis>false</emphasis>:
3858             the conversion would require a <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">const_cast</phrase></computeroutput>.
3859           </para>
3860         </para>
3861       </blockquote>
3862       <blockquote>
3863         <para>
3864           <para>
3865             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_convertible</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">&amp;,</phrase> <phrase role="keyword">long</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
3866             is an integral constant expression that evaluates to <emphasis>true</emphasis>.
3867           </para>
3868         </para>
3869       </blockquote>
3870       <blockquote>
3871         <para>
3872           <para>
3873             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_convertible</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
3874             that evaluates to <emphasis>false</emphasis>.
3875           </para>
3876         </para>
3877       </blockquote>
3878       <blockquote>
3879         <para>
3880           <para>
3881             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_convertible</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
3882           </para>
3883         </para>
3884       </blockquote>
3885     </section>
3886     <section id="boost_typetraits.reference.is_empty"><indexterm type="class_name"><primary>is_empty</primary><secondary>is_empty</secondary></indexterm>
3887       <title><link linkend="boost_typetraits.reference.is_empty"> is_empty</link></title>
3888
3889 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
3890 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_empty</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
3891 </programlisting>
3892       <para>
3893         <emphasis role="bold">Inherits:</emphasis> If T is an empty class type then
3894         inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
3895         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
3896       </para>
3897       <para>
3898         <emphasis role="bold">C++ Standard Reference:</emphasis> 10p5.
3899       </para>
3900       <para>
3901         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
3902         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_empty</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3903         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3904       </para>
3905       <para>
3906         <emphasis role="bold">Compiler Compatibility:</emphasis> In order to correctly
3907         detect empty classes this trait relies on either:
3908       </para>
3909       <itemizedlist>
3910         <listitem>
3911           the compiler implementing zero sized empty base classes, or
3912         </listitem>
3913         <listitem>
3914           the compiler providing <link linkend="boost_typetraits.intrinsics">intrinsics</link>
3915           to detect empty classes.
3916         </listitem>
3917       </itemizedlist>
3918       <para>
3919         Can not be used with incomplete types.
3920       </para>
3921       <para>
3922         Can not be used with union types, until is_union can be made to work.
3923       </para>
3924       <para>
3925         If the compiler does not support partial-specialization of class templates,
3926         then this template can not be used with abstract types.
3927       </para>
3928       <para>
3929         <emphasis role="bold">Examples:</emphasis>
3930       </para>
3931       <blockquote>
3932         <para>
3933           <para>
3934             Given: <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">struct</phrase> <phrase role="identifier">empty_class</phrase>
3935             <phrase role="special">{};</phrase></computeroutput>
3936           </para>
3937         </para>
3938       </blockquote>
3939       <blockquote>
3940         <para>
3941           <para>
3942             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_empty</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">empty_class</phrase><phrase role="special">&gt;</phrase></computeroutput>
3943             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
3944           </para>
3945         </para>
3946       </blockquote>
3947       <blockquote>
3948         <para>
3949           <para>
3950             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_empty</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">empty_class</phrase> <phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
3951             is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
3952           </para>
3953         </para>
3954       </blockquote>
3955       <blockquote>
3956         <para>
3957           <para>
3958             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_empty</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">empty_class</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
3959             that evaluates to <emphasis>true</emphasis>.
3960           </para>
3961         </para>
3962       </blockquote>
3963       <blockquote>
3964         <para>
3965           <para>
3966             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_empty</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
3967           </para>
3968         </para>
3969       </blockquote>
3970     </section>
3971     <section id="boost_typetraits.reference.is_enum"><indexterm type="class_name"><primary>is_enum</primary><secondary>is_enum</secondary></indexterm>
3972       <title><link linkend="boost_typetraits.reference.is_enum"> is_enum</link></title>
3973
3974 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
3975 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_enum</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
3976 </programlisting>
3977       <para>
3978         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
3979         enum type then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
3980         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
3981       </para>
3982       <para>
3983         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.2 and 7.2.
3984       </para>
3985       <para>
3986         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
3987         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_enum</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3988         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
3989       </para>
3990       <para>
3991         <emphasis role="bold">Compiler Compatibility:</emphasis> Requires a correctly
3992         functioning <link linkend="boost_typetraits.reference.is_convertible">is_convertible</link>
3993         template; this means that is_enum is currently broken under Borland C++ Builder
3994         5, and for the Metrowerks compiler prior to version 8, other compilers should
3995         handle this template just fine.
3996       </para>
3997       <para>
3998         <emphasis role="bold">Examples:</emphasis>
3999       </para>
4000       <blockquote>
4001         <para>
4002           <para>
4003             Given: <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">enum</phrase> <phrase role="identifier">my_enum</phrase>
4004             <phrase role="special">{</phrase> <phrase role="identifier">one</phrase><phrase role="special">,</phrase> <phrase role="identifier">two</phrase> <phrase role="special">};</phrase></computeroutput>
4005           </para>
4006         </para>
4007       </blockquote>
4008       <blockquote>
4009         <para>
4010           <para>
4011             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_enum</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">my_enum</phrase><phrase role="special">&gt;</phrase></computeroutput>
4012             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4013           </para>
4014         </para>
4015       </blockquote>
4016       <blockquote>
4017         <para>
4018           <para>
4019             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_enum</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">my_enum</phrase> <phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
4020             is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4021           </para>
4022         </para>
4023       </blockquote>
4024       <blockquote>
4025         <para>
4026           <para>
4027             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_enum</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">my_enum</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4028             that evaluates to <emphasis>true</emphasis>.
4029           </para>
4030         </para>
4031       </blockquote>
4032       <blockquote>
4033         <para>
4034           <para>
4035             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_enum</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">my_enum</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4036             that evaluates to <emphasis>false</emphasis>.
4037           </para>
4038         </para>
4039       </blockquote>
4040       <blockquote>
4041         <para>
4042           <para>
4043             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_enum</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">my_enum</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4044             that evaluates to <emphasis>false</emphasis>.
4045           </para>
4046         </para>
4047       </blockquote>
4048       <blockquote>
4049         <para>
4050           <para>
4051             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_enum</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
4052           </para>
4053         </para>
4054       </blockquote>
4055     </section>
4056     <section id="boost_typetraits.reference.is_floating_point"><indexterm type="class_name"><primary>is_floating_point</primary><secondary>is_floating_point</secondary></indexterm>
4057       <title><link linkend="boost_typetraits.reference.is_floating_point"> is_floating_point</link></title>
4058
4059 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
4060 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_floating_point</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
4061 </programlisting>
4062       <para>
4063         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
4064         floating point type then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
4065         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
4066       </para>
4067       <para>
4068         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.1p8.
4069       </para>
4070       <para>
4071         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
4072         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_floating_point</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4073         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4074       </para>
4075       <para>
4076         <emphasis role="bold">Examples:</emphasis>
4077       </para>
4078       <blockquote>
4079         <para>
4080           <para>
4081             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_floating_point</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">float</phrase><phrase role="special">&gt;</phrase></computeroutput>
4082             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4083           </para>
4084         </para>
4085       </blockquote>
4086       <blockquote>
4087         <para>
4088           <para>
4089             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_floating_point</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">double</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4090           </para>
4091         </para>
4092       </blockquote>
4093       <blockquote>
4094         <para>
4095           <para>
4096             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_floating_point</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">long</phrase> <phrase role="keyword">double</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
4097             is an integral constant expression that evaluates to <emphasis>true</emphasis>.
4098           </para>
4099         </para>
4100       </blockquote>
4101       <blockquote>
4102         <para>
4103           <para>
4104             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_floating_point</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
4105           </para>
4106         </para>
4107       </blockquote>
4108     </section>
4109     <section id="boost_typetraits.reference.is_function"><indexterm type="class_name"><primary>is_function</primary><secondary>is_function</secondary></indexterm>
4110       <title><link linkend="boost_typetraits.reference.is_function"> is_function</link></title>
4111
4112 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
4113 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_function</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
4114 </programlisting>
4115       <para>
4116         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
4117         function type then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
4118         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
4119         Note that this template does not detect <emphasis>pointers to functions</emphasis>,
4120         or <emphasis>references to functions</emphasis>, these are detected by <link linkend="boost_typetraits.reference.is_pointer">is_pointer</link> and <link linkend="boost_typetraits.reference.is_reference">is_reference</link> respectively:
4121       </para>
4122
4123 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">typedef</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">f1</phrase><phrase role="special">();</phrase>      <phrase role="comment">// f1 is of function type.
4124 </phrase><phrase role="keyword">typedef</phrase> <phrase role="keyword">int</phrase> <phrase role="special">(</phrase><phrase role="identifier">f2</phrase><phrase role="special">*)();</phrase>   <phrase role="comment">// f2 is a pointer to a function.
4125 </phrase><phrase role="keyword">typedef</phrase> <phrase role="keyword">int</phrase> <phrase role="special">(</phrase><phrase role="identifier">f3</phrase><phrase role="special">&amp;)();</phrase>   <phrase role="comment">// f3 is a reference to a function.
4126 </phrase></programlisting>
4127       <para>
4128         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.2p1 and 8.3.5.
4129       </para>
4130       <para>
4131         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
4132         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_function</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4133         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4134       </para>
4135       <para>
4136         <emphasis role="bold">Examples:</emphasis>
4137       </para>
4138       <blockquote>
4139         <para>
4140           <para>
4141             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_function</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(</phrase><phrase role="keyword">void</phrase><phrase role="special">)&gt;</phrase></computeroutput>
4142             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4143           </para>
4144         </para>
4145       </blockquote>
4146       <blockquote>
4147         <para>
4148           <para>
4149             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_function</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">long</phrase> <phrase role="special">(</phrase><phrase role="keyword">double</phrase><phrase role="special">,</phrase> <phrase role="keyword">int</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4150           </para>
4151         </para>
4152       </blockquote>
4153       <blockquote>
4154         <para>
4155           <para>
4156             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_function</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">long</phrase> <phrase role="special">(</phrase><phrase role="keyword">double</phrase><phrase role="special">,</phrase> <phrase role="keyword">int</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4157             that evaluates to <emphasis>true</emphasis>.
4158           </para>
4159         </para>
4160       </blockquote>
4161       <blockquote>
4162         <para>
4163           <para>
4164             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_function</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">long</phrase> <phrase role="special">(*)(</phrase><phrase role="keyword">double</phrase><phrase role="special">,</phrase> <phrase role="keyword">int</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4165             that evaluates to <emphasis>false</emphasis>: the argument in this case
4166             is a pointer type, not a function type.
4167           </para>
4168         </para>
4169       </blockquote>
4170       <blockquote>
4171         <para>
4172           <para>
4173             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_function</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">long</phrase> <phrase role="special">(&amp;)(</phrase><phrase role="keyword">double</phrase><phrase role="special">,</phrase> <phrase role="keyword">int</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4174             that evaluates to <emphasis>false</emphasis>: the argument in this case
4175             is a reference to a function, not a function type.
4176           </para>
4177         </para>
4178       </blockquote>
4179       <blockquote>
4180         <para>
4181           <para>
4182             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_function</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">long</phrase> <phrase role="special">(</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">::*)(</phrase><phrase role="keyword">double</phrase><phrase role="special">,</phrase> <phrase role="keyword">int</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4183             that evaluates to <emphasis>false</emphasis>: the argument in this case
4184             is a pointer to a member function.
4185           </para>
4186         </para>
4187       </blockquote>
4188       <blockquote>
4189         <para>
4190           <para>
4191             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_function</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
4192           </para>
4193         </para>
4194       </blockquote>
4195       <tip>
4196         <para>
4197           Don't confuse function-types with pointers to functions:
4198         </para>
4199         <para>
4200           <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">typedef</phrase> <phrase role="keyword">int</phrase>
4201           <phrase role="identifier">f</phrase><phrase role="special">(</phrase><phrase role="keyword">double</phrase><phrase role="special">);</phrase></computeroutput>
4202         </para>
4203         <para>
4204           defines a function type,
4205         </para>
4206         <para>
4207           <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">f</phrase> <phrase role="identifier">foo</phrase><phrase role="special">;</phrase></computeroutput>
4208         </para>
4209         <para>
4210           declares a prototype for a function of type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">f</phrase></computeroutput>,
4211         </para>
4212         <para>
4213           <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">f</phrase><phrase role="special">*</phrase>
4214           <phrase role="identifier">pf</phrase> <phrase role="special">=</phrase>
4215           <phrase role="identifier">foo</phrase><phrase role="special">;</phrase></computeroutput>
4216         </para>
4217         <para>
4218           <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">f</phrase><phrase role="special">&amp;</phrase>
4219           <phrase role="identifier">fr</phrase> <phrase role="special">=</phrase>
4220           <phrase role="identifier">foo</phrase><phrase role="special">;</phrase></computeroutput>
4221         </para>
4222         <para>
4223           declares a pointer and a reference to the function <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">foo</phrase></computeroutput>.
4224         </para>
4225         <para>
4226           If you want to detect whether some type is a pointer-to-function then use:
4227         </para>
4228         <para>
4229           <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.is_function">is_function</link><phrase role="special">&lt;</phrase><link linkend="boost_typetraits.reference.remove_pointer">remove_pointer</link><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase>
4230           <phrase role="special">&amp;&amp;</phrase> <link linkend="boost_typetraits.reference.is_pointer">is_pointer</link><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
4231         </para>
4232         <para>
4233           or for pointers to member functions you can just use <link linkend="boost_typetraits.reference.is_member_function_pointer">is_member_function_pointer</link>
4234           directly.
4235         </para>
4236       </tip>
4237     </section>
4238     <section id="boost_typetraits.reference.is_fundamental"><indexterm type="class_name"><primary>is_fundamental</primary><secondary>is_fundamental</secondary></indexterm>
4239       <title><link linkend="boost_typetraits.reference.is_fundamental"> is_fundamental</link></title>
4240
4241 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
4242 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_fundamental</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
4243 </programlisting>
4244       <para>
4245         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
4246         fundamental type then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
4247         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
4248         Fundamental types include integral, floating point and void types (see also
4249         <link linkend="boost_typetraits.reference.is_integral">is_integral</link>,
4250         <link linkend="boost_typetraits.reference.is_floating_point">is_floating_point</link>
4251         and <link linkend="boost_typetraits.reference.is_void">is_void</link>)
4252       </para>
4253       <para>
4254         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.1.
4255       </para>
4256       <para>
4257         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
4258         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_fundamental</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4259         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4260       </para>
4261       <para>
4262         <emphasis role="bold">Examples:</emphasis>
4263       </para>
4264       <blockquote>
4265         <para>
4266           <para>
4267             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_fundamental</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">)&gt;</phrase></computeroutput>
4268             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4269           </para>
4270         </para>
4271       </blockquote>
4272       <blockquote>
4273         <para>
4274           <para>
4275             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_fundamental</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">double</phrase> <phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
4276             is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4277           </para>
4278         </para>
4279       </blockquote>
4280       <blockquote>
4281         <para>
4282           <para>
4283             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_fundamental</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">void</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4284             that evaluates to <emphasis>true</emphasis>.
4285           </para>
4286         </para>
4287       </blockquote>
4288       <blockquote>
4289         <para>
4290           <para>
4291             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_fundamental</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
4292           </para>
4293         </para>
4294       </blockquote>
4295     </section>
4296     <section id="boost_typetraits.reference.is_integral"><indexterm type="class_name"><primary>is_integral</primary><secondary>is_integral</secondary></indexterm>
4297       <title><link linkend="boost_typetraits.reference.is_integral"> is_integral</link></title>
4298
4299 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
4300 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_integral</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
4301 </programlisting>
4302       <para>
4303         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
4304         integral type then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
4305         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
4306       </para>
4307       <para>
4308         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.1p7.
4309       </para>
4310       <para>
4311         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
4312         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_integral</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4313         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4314       </para>
4315       <para>
4316         <emphasis role="bold">Examples:</emphasis>
4317       </para>
4318       <blockquote>
4319         <para>
4320           <para>
4321             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_integral</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;</phrase></computeroutput>
4322             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4323           </para>
4324         </para>
4325       </blockquote>
4326       <blockquote>
4327         <para>
4328           <para>
4329             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_integral</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">const</phrase> <phrase role="keyword">char</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
4330             is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4331           </para>
4332         </para>
4333       </blockquote>
4334       <blockquote>
4335         <para>
4336           <para>
4337             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_integral</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">long</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4338             that evaluates to <emphasis>true</emphasis>.
4339           </para>
4340         </para>
4341       </blockquote>
4342       <blockquote>
4343         <para>
4344           <para>
4345             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_integral</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
4346           </para>
4347         </para>
4348       </blockquote>
4349     </section>
4350     <section id="boost_typetraits.reference.is_member_function_pointer"><indexterm type="class_name"><primary>is_member_function_pointer</primary><secondary>is_member_function_pointer</secondary></indexterm>
4351       <title><link linkend="boost_typetraits.reference.is_member_function_pointer">
4352       is_member_function_pointer</link></title>
4353 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
4354 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_member_function_pointer</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
4355 </programlisting>
4356       <para>
4357         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
4358         pointer to a member function then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
4359         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
4360       </para>
4361       <para>
4362         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.2 and 8.3.3.
4363       </para>
4364       <para>
4365         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
4366         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_member_function_pointer</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4367         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4368       </para>
4369       <para>
4370         <emphasis role="bold">Examples:</emphasis>
4371       </para>
4372       <blockquote>
4373         <para>
4374           <para>
4375             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_member_function_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">::*)(</phrase><phrase role="keyword">void</phrase><phrase role="special">)&gt;</phrase></computeroutput> inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4376           </para>
4377         </para>
4378       </blockquote>
4379       <blockquote>
4380         <para>
4381           <para>
4382             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_member_function_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">::*)(</phrase><phrase role="keyword">char</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
4383             is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4384           </para>
4385         </para>
4386       </blockquote>
4387       <blockquote>
4388         <para>
4389           <para>
4390             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_member_function_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">::*)(</phrase><phrase role="keyword">void</phrase><phrase role="special">)</phrase><phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
4391             is an integral constant expression that evaluates to <emphasis>true</emphasis>.
4392           </para>
4393         </para>
4394       </blockquote>
4395       <blockquote>
4396         <para>
4397           <para>
4398             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_member_function_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">::*)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
4399             is an integral constant expression that evaluates to <emphasis>false</emphasis>:
4400             the argument in this case is a pointer to a data member and not a member
4401             function, see <link linkend="boost_typetraits.reference.is_member_object_pointer">is_member_object_pointer</link>
4402             and <link linkend="boost_typetraits.reference.is_member_pointer">is_member_pointer</link>
4403           </para>
4404         </para>
4405       </blockquote>
4406       <blockquote>
4407         <para>
4408           <para>
4409             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_member_function_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput>
4410             is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
4411           </para>
4412         </para>
4413       </blockquote>
4414     </section>
4415     <section id="boost_typetraits.reference.is_member_object_pointer"><indexterm type="class_name"><primary>is_member_object_pointer</primary><secondary>is_member_object_pointer</secondary></indexterm>
4416       <title><link linkend="boost_typetraits.reference.is_member_object_pointer">
4417       is_member_object_pointer</link></title>
4418 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
4419 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_member_object_pointer</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
4420 </programlisting>
4421       <para>
4422         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
4423         pointer to a member object (a data member) then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
4424         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
4425       </para>
4426       <para>
4427         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.2 and 8.3.3.
4428       </para>
4429       <para>
4430         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
4431         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_member_object_pointer</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4432         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4433       </para>
4434       <para>
4435         <emphasis role="bold">Examples:</emphasis>
4436       </para>
4437       <blockquote>
4438         <para>
4439           <para>
4440             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_member_object_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">::*)&gt;</phrase></computeroutput> inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4441           </para>
4442         </para>
4443       </blockquote>
4444       <blockquote>
4445         <para>
4446           <para>
4447             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_member_object_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">double</phrase> <phrase role="special">(</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">::*)&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
4448             is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4449           </para>
4450         </para>
4451       </blockquote>
4452       <blockquote>
4453         <para>
4454           <para>
4455             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_member_object_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">const</phrase> <phrase role="keyword">int</phrase> <phrase role="special">(</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">::*)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4456             that evaluates to <emphasis>true</emphasis>.
4457           </para>
4458         </para>
4459       </blockquote>
4460       <blockquote>
4461         <para>
4462           <para>
4463             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_member_object_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">::*)(</phrase><phrase role="keyword">void</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
4464             is an integral constant expression that evaluates to <emphasis>false</emphasis>:
4465             the argument in this case is a pointer to a member function and not a
4466             member object, see <link linkend="boost_typetraits.reference.is_member_function_pointer">is_member_function_pointer</link>
4467             and <link linkend="boost_typetraits.reference.is_member_pointer">is_member_pointer</link>
4468           </para>
4469         </para>
4470       </blockquote>
4471       <blockquote>
4472         <para>
4473           <para>
4474             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_member_object_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput>
4475             is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
4476           </para>
4477         </para>
4478       </blockquote>
4479     </section>
4480     <section id="boost_typetraits.reference.is_member_pointer"><indexterm type="class_name"><primary>is_member_pointer</primary><secondary>is_member_pointer</secondary></indexterm>
4481       <title><link linkend="boost_typetraits.reference.is_member_pointer"> is_member_pointer</link></title>
4482
4483 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
4484 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_member_pointer</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
4485 </programlisting>
4486       <para>
4487         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
4488         pointer to a member (either a function or a data member) then inherits from
4489         <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
4490         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
4491       </para>
4492       <para>
4493         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.2 and 8.3.3.
4494       </para>
4495       <para>
4496         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
4497         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_member_pointer</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4498         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4499       </para>
4500       <para>
4501         <emphasis role="bold">Examples:</emphasis>
4502       </para>
4503       <blockquote>
4504         <para>
4505           <para>
4506             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_member_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">::*)&gt;</phrase></computeroutput>
4507             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4508           </para>
4509         </para>
4510       </blockquote>
4511       <blockquote>
4512         <para>
4513           <para>
4514             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_member_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">::*)(</phrase><phrase role="keyword">char</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4515           </para>
4516         </para>
4517       </blockquote>
4518       <blockquote>
4519         <para>
4520           <para>
4521             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_member_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">::*)(</phrase><phrase role="keyword">void</phrase><phrase role="special">)</phrase><phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4522             that evaluates to <emphasis>true</emphasis>.
4523           </para>
4524         </para>
4525       </blockquote>
4526       <blockquote>
4527         <para>
4528           <para>
4529             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_member_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
4530           </para>
4531         </para>
4532       </blockquote>
4533     </section>
4534     <section id="boost_typetraits.reference.is_object"><indexterm type="class_name"><primary>is_object</primary><secondary>is_object</secondary></indexterm>
4535       <title><link linkend="boost_typetraits.reference.is_object"> is_object</link></title>
4536
4537 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
4538 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_object</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
4539 </programlisting>
4540       <para>
4541         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
4542         object type then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
4543         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
4544         All types are object types except references, void, and function types.
4545       </para>
4546       <para>
4547         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9p9.
4548       </para>
4549       <para>
4550         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
4551         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_object</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4552         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4553       </para>
4554       <para>
4555         <emphasis role="bold">Examples:</emphasis>
4556       </para>
4557       <blockquote>
4558         <para>
4559           <para>
4560             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_object</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;</phrase></computeroutput>
4561             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4562           </para>
4563         </para>
4564       </blockquote>
4565       <blockquote>
4566         <para>
4567           <para>
4568             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_object</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4569           </para>
4570         </para>
4571       </blockquote>
4572       <blockquote>
4573         <para>
4574           <para>
4575             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_object</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(*)(</phrase><phrase role="keyword">void</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4576             that evaluates to <emphasis>true</emphasis>.
4577           </para>
4578         </para>
4579       </blockquote>
4580       <blockquote>
4581         <para>
4582           <para>
4583             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_object</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">::*)(</phrase><phrase role="keyword">void</phrase><phrase role="special">)</phrase><phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4584             that evaluates to <emphasis>true</emphasis>.
4585           </para>
4586         </para>
4587       </blockquote>
4588       <blockquote>
4589         <para>
4590           <para>
4591             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_object</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4592             that evaluates to <emphasis>false</emphasis>: reference types are not
4593             objects
4594           </para>
4595         </para>
4596       </blockquote>
4597       <blockquote>
4598         <para>
4599           <para>
4600             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_object</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(</phrase><phrase role="keyword">double</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4601             that evaluates to <emphasis>false</emphasis>: function types are not
4602             objects
4603           </para>
4604         </para>
4605       </blockquote>
4606       <blockquote>
4607         <para>
4608           <para>
4609             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_object</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">const</phrase> <phrase role="keyword">void</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
4610             is an integral constant expression that evaluates to <emphasis>false</emphasis>:
4611             void is not an object type
4612           </para>
4613         </para>
4614       </blockquote>
4615       <blockquote>
4616         <para>
4617           <para>
4618             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_object</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
4619           </para>
4620         </para>
4621       </blockquote>
4622     </section>
4623     <section id="boost_typetraits.reference.is_pod">
4624       <title><link linkend="boost_typetraits.reference.is_pod"> is_pod</link></title>
4625
4626 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
4627 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_pod</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
4628 </programlisting>
4629       <para>
4630         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
4631         POD type then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
4632         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
4633       </para>
4634       <para>
4635         POD stands for "Plain old data". Arithmetic types, and enumeration
4636         types, a pointers and pointer to members are all PODs. Classes and unions
4637         can also be POD's if they have no non-static data members that are of reference
4638         or non-POD type, no user defined constructors, no user defined assignment
4639         operators, no private or protected non-static data members, no virtual functions
4640         and no base classes. Finally, a cv-qualified POD is still a POD, as is an
4641         array of PODs.
4642       </para>
4643       <para>
4644         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9p10 and 9p4 (Note
4645         that POD's are also aggregates, see 8.5.1).
4646       </para>
4647       <para>
4648         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
4649         does not support partial-specialization of class templates, then this template
4650         can not be used with function types.
4651       </para>
4652       <para>
4653         Without some (as yet unspecified) help from the compiler, is<emphasis role="underline">pod
4654         will never report that a class or struct is a POD; this is always safe, if
4655         possibly sub-optimal. Currently (May 2005) only MWCW 9 and Visual C++ 8 have
4656         the necessary compiler-</emphasis>_intrinsics.
4657       </para>
4658       <para>
4659         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
4660         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_pod</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4661         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4662       </para>
4663       <para>
4664         <emphasis role="bold">Examples:</emphasis>
4665       </para>
4666       <blockquote>
4667         <para>
4668           <para>
4669             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_pod</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;</phrase></computeroutput>
4670             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4671           </para>
4672         </para>
4673       </blockquote>
4674       <blockquote>
4675         <para>
4676           <para>
4677             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_pod</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4678           </para>
4679         </para>
4680       </blockquote>
4681       <blockquote>
4682         <para>
4683           <para>
4684             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_pod</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(*)(</phrase><phrase role="keyword">long</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4685             that evaluates to <emphasis>true</emphasis>.
4686           </para>
4687         </para>
4688       </blockquote>
4689       <blockquote>
4690         <para>
4691           <para>
4692             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_pod</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4693             that evaluates to <emphasis>false</emphasis>.
4694           </para>
4695         </para>
4696       </blockquote>
4697       <blockquote>
4698         <para>
4699           <para>
4700             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_pod</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
4701           </para>
4702         </para>
4703       </blockquote>
4704     </section>
4705     <section id="boost_typetraits.reference.is_pointer"><indexterm type="class_name"><primary>is_pointer</primary><secondary>is_pointer</secondary></indexterm>
4706       <title><link linkend="boost_typetraits.reference.is_pointer"> is_pointer</link></title>
4707
4708 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
4709 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_pointer</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
4710 </programlisting>
4711       <para>
4712         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
4713         pointer type (includes function pointers, but excludes pointers to members)
4714         then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
4715         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
4716       </para>
4717       <para>
4718         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.2p2 and 8.3.1.
4719       </para>
4720       <para>
4721         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
4722         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_pointer</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4723         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4724       </para>
4725       <para>
4726         <emphasis role="bold">Examples:</emphasis>
4727       </para>
4728       <blockquote>
4729         <para>
4730           <para>
4731             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">*&gt;</phrase></computeroutput>
4732             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4733           </para>
4734         </para>
4735       </blockquote>
4736       <blockquote>
4737         <para>
4738           <para>
4739             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase><phrase role="special">*</phrase> <phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4740           </para>
4741         </para>
4742       </blockquote>
4743       <blockquote>
4744         <para>
4745           <para>
4746             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(*)(</phrase><phrase role="keyword">long</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4747             that evaluates to <emphasis>true</emphasis>.
4748           </para>
4749         </para>
4750       </blockquote>
4751       <blockquote>
4752         <para>
4753           <para>
4754             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">::*)(</phrase><phrase role="keyword">long</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4755             that evaluates to <emphasis>false</emphasis>.
4756           </para>
4757         </para>
4758       </blockquote>
4759       <blockquote>
4760         <para>
4761           <para>
4762             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">::*)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4763             that evaluates to <emphasis>false</emphasis>.
4764           </para>
4765         </para>
4766       </blockquote>
4767       <blockquote>
4768         <para>
4769           <para>
4770             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
4771           </para>
4772         </para>
4773       </blockquote>
4774       <important>
4775         <para>
4776           <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_pointer</phrase></computeroutput> detects "real"
4777           pointer types only, and <emphasis>not</emphasis> smart pointers. Users
4778           should not specialise <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_pointer</phrase></computeroutput>
4779           for smart pointer types, as doing so may cause Boost (and other third party)
4780           code to fail to function correctly. Users wanting a trait to detect smart
4781           pointers should create their own. However, note that there is no way in
4782           general to auto-magically detect smart pointer types, so such a trait would
4783           have to be partially specialised for each supported smart pointer type.
4784         </para>
4785       </important>
4786     </section>
4787     <section id="boost_typetraits.reference.is_polymorphic"><indexterm type="class_name"><primary>is_polymorphic</primary><secondary>is_polymorphic</secondary></indexterm>
4788       <title><link linkend="boost_typetraits.reference.is_polymorphic"> is_polymorphic</link></title>
4789
4790 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
4791 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_polymorphic</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
4792 </programlisting>
4793       <para>
4794         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
4795         polymorphic type then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
4796         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
4797         Type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput> must be a complete
4798         type.
4799       </para>
4800       <para>
4801         <emphasis role="bold">C++ Standard Reference:</emphasis> 10.3.
4802       </para>
4803       <para>
4804         <emphasis role="bold">Compiler Compatibility:</emphasis> The implementation
4805         requires some knowledge of the compilers ABI, it does actually seem to work
4806         with the majority of compilers though.
4807       </para>
4808       <para>
4809         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
4810         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_polymorphic</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4811         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4812       </para>
4813       <para>
4814         <emphasis role="bold">Examples:</emphasis>
4815       </para>
4816       <blockquote>
4817         <para>
4818           <para>
4819             Given: <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">class</phrase> <phrase role="identifier">poly</phrase><phrase role="special">{</phrase> <phrase role="keyword">virtual</phrase> <phrase role="special">~</phrase><phrase role="identifier">poly</phrase><phrase role="special">();</phrase> <phrase role="special">};</phrase></computeroutput>
4820           </para>
4821         </para>
4822       </blockquote>
4823       <blockquote>
4824         <para>
4825           <para>
4826             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_polymorphic</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">poly</phrase><phrase role="special">&gt;</phrase></computeroutput>
4827             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4828           </para>
4829         </para>
4830       </blockquote>
4831       <blockquote>
4832         <para>
4833           <para>
4834             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_polymorphic</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">poly</phrase> <phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
4835             is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4836           </para>
4837         </para>
4838       </blockquote>
4839       <blockquote>
4840         <para>
4841           <para>
4842             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_polymorphic</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">poly</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4843             that evaluates to <emphasis>true</emphasis>.
4844           </para>
4845         </para>
4846       </blockquote>
4847       <blockquote>
4848         <para>
4849           <para>
4850             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_polymorphic</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
4851           </para>
4852         </para>
4853       </blockquote>
4854     </section>
4855     <section id="boost_typetraits.reference.is_same"><indexterm type="class_name"><primary>is_same</primary><secondary>is_same</secondary></indexterm>
4856       <title><link linkend="boost_typetraits.reference.is_same"> is_same</link></title>
4857
4858 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">,</phrase> <phrase role="keyword">class</phrase> <phrase role="identifier">U</phrase><phrase role="special">&gt;</phrase>
4859 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_same</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
4860 </programlisting>
4861       <para>
4862         <emphasis role="bold">Inherits:</emphasis> If T and U are the same types
4863         then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
4864         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
4865       </para>
4866       <para>
4867         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
4868         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_same</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4869         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4870       </para>
4871       <para>
4872         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
4873         does not support partial-specialization of class templates, then this template
4874         can not be used with abstract, incomplete or function types.
4875       </para>
4876       <para>
4877         <emphasis role="bold">Examples:</emphasis>
4878       </para>
4879       <blockquote>
4880         <para>
4881           <para>
4882             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_same</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">,</phrase> <phrase role="keyword">int</phrase><phrase role="special">&gt;</phrase></computeroutput>
4883             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4884           </para>
4885         </para>
4886       </blockquote>
4887       <blockquote>
4888         <para>
4889           <para>
4890             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_same</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">,</phrase> <phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4891           </para>
4892         </para>
4893       </blockquote>
4894       <blockquote>
4895         <para>
4896           <para>
4897             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_same</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">,</phrase> <phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4898             that evaluates to <emphasis>true</emphasis>.
4899           </para>
4900         </para>
4901       </blockquote>
4902       <blockquote>
4903         <para>
4904           <para>
4905             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_same</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">,</phrase> <phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
4906             is an integral constant expression that evaluates to <emphasis>false</emphasis>.
4907           </para>
4908         </para>
4909       </blockquote>
4910       <blockquote>
4911         <para>
4912           <para>
4913             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_same</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&amp;,</phrase> <phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4914             that evaluates to <emphasis>false</emphasis>.
4915           </para>
4916         </para>
4917       </blockquote>
4918       <blockquote>
4919         <para>
4920           <para>
4921             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_same</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
4922           </para>
4923         </para>
4924       </blockquote>
4925     </section>
4926     <section id="boost_typetraits.reference.is_scalar"><indexterm type="class_name"><primary>is_scalar</primary><secondary>is_scalar</secondary></indexterm>
4927       <title><link linkend="boost_typetraits.reference.is_scalar"> is_scalar</link></title>
4928
4929 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
4930 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_scalar</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
4931 </programlisting>
4932       <para>
4933         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
4934         scalar type then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
4935         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
4936         Scalar types include integral, floating point, enumeration, pointer, and
4937         pointer-to-member types.
4938       </para>
4939       <para>
4940         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9p10.
4941       </para>
4942       <para>
4943         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
4944         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_scalar</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4945         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
4946       </para>
4947       <para>
4948         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
4949         does not support partial-specialization of class templates, then this template
4950         can not be used with function types.
4951       </para>
4952       <para>
4953         <emphasis role="bold">Examples:</emphasis>
4954       </para>
4955       <blockquote>
4956         <para>
4957           <para>
4958             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_scalar</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">*&gt;</phrase></computeroutput>
4959             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4960           </para>
4961         </para>
4962       </blockquote>
4963       <blockquote>
4964         <para>
4965           <para>
4966             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_scalar</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
4967           </para>
4968         </para>
4969       </blockquote>
4970       <blockquote>
4971         <para>
4972           <para>
4973             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_scalar</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">double</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4974             that evaluates to <emphasis>true</emphasis>.
4975           </para>
4976         </para>
4977       </blockquote>
4978       <blockquote>
4979         <para>
4980           <para>
4981             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_scalar</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(*)(</phrase><phrase role="keyword">long</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4982             that evaluates to <emphasis>true</emphasis>.
4983           </para>
4984         </para>
4985       </blockquote>
4986       <blockquote>
4987         <para>
4988           <para>
4989             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_scalar</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">::*)(</phrase><phrase role="keyword">long</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4990             that evaluates to <emphasis>true</emphasis>.
4991           </para>
4992         </para>
4993       </blockquote>
4994       <blockquote>
4995         <para>
4996           <para>
4997             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_scalar</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(</phrase><phrase role="identifier">MyClass</phrase><phrase role="special">::*)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
4998             that evaluates to <emphasis>true</emphasis>.
4999           </para>
5000         </para>
5001       </blockquote>
5002       <blockquote>
5003         <para>
5004           <para>
5005             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_scalar</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
5006           </para>
5007         </para>
5008       </blockquote>
5009     </section>
5010     <section id="boost_typetraits.reference.is_signed"><indexterm type="class_name"><primary>is_signed</primary><secondary>is_signed</secondary></indexterm>
5011       <title><link linkend="boost_typetraits.reference.is_signed"> is_signed</link></title>
5012
5013 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
5014 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_signed</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
5015 </programlisting>
5016       <para>
5017         <emphasis role="bold">Inherits:</emphasis> If T is an signed integer type
5018         or an enumerated type with an underlying signed integer type, then inherits
5019         from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
5020         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
5021       </para>
5022       <para>
5023         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.1, 7.2.
5024       </para>
5025       <para>
5026         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
5027         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_signed</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5028         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5029       </para>
5030       <para>
5031         <emphasis role="bold">Examples:</emphasis>
5032       </para>
5033       <blockquote>
5034         <para>
5035           <para>
5036             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_signed</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;</phrase></computeroutput>
5037             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
5038           </para>
5039         </para>
5040       </blockquote>
5041       <blockquote>
5042         <para>
5043           <para>
5044             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_signed</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase> <phrase role="keyword">volatile</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
5045           </para>
5046         </para>
5047       </blockquote>
5048       <blockquote>
5049         <para>
5050           <para>
5051             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_signed</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">unsigned</phrase> <phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
5052             is an integral constant expression that evaluates to <emphasis>false</emphasis>.
5053           </para>
5054         </para>
5055       </blockquote>
5056       <blockquote>
5057         <para>
5058           <para>
5059             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_signed</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">myclass</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
5060             that evaluates to <emphasis>false</emphasis>.
5061           </para>
5062         </para>
5063       </blockquote>
5064       <blockquote>
5065         <para>
5066           <para>
5067             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_signed</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
5068             whose value depends upon the signedness of type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">char</phrase></computeroutput>.
5069           </para>
5070         </para>
5071       </blockquote>
5072       <blockquote>
5073         <para>
5074           <para>
5075             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_signed</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">long</phrase> <phrase role="keyword">long</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
5076             is an integral constant expression that evaluates to <emphasis>true</emphasis>.
5077           </para>
5078         </para>
5079       </blockquote>
5080       <blockquote>
5081         <para>
5082           <para>
5083             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_signed</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
5084           </para>
5085         </para>
5086       </blockquote>
5087     </section>
5088     <section id="boost_typetraits.reference.is_stateless">
5089       <title><link linkend="boost_typetraits.reference.is_stateless"> is_stateless</link></title>
5090
5091 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
5092 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_stateless</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
5093 </programlisting>
5094       <para>
5095         <emphasis role="bold">Inherits:</emphasis> Ff T is a stateless type then
5096         inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
5097         otherwise from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
5098       </para>
5099       <para>
5100         Type T must be a complete type.
5101       </para>
5102       <para>
5103         A stateless type is a type that has no storage and whose constructors and
5104         destructors are trivial. That means that <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_stateless</phrase></computeroutput>
5105         only inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>
5106         if the following expression is <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">true</phrase></computeroutput>:
5107       </para>
5108
5109 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="special">::</phrase><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">has_trivial_constructor</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase>
5110 <phrase role="special">&amp;&amp;</phrase> <phrase role="special">::</phrase><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">has_trivial_copy</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase>
5111 <phrase role="special">&amp;&amp;</phrase> <phrase role="special">::</phrase><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">has_trivial_destructor</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase>
5112 <phrase role="special">&amp;&amp;</phrase> <phrase role="special">::</phrase><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">is_class</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase>
5113 <phrase role="special">&amp;&amp;</phrase> <phrase role="special">::</phrase><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">is_empty</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase>
5114 </programlisting>
5115       <para>
5116         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9p10.
5117       </para>
5118       <para>
5119         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
5120         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_stateless</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5121         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5122       </para>
5123       <para>
5124         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
5125         does not support partial-specialization of class templates, then this template
5126         can not be used with function types.
5127       </para>
5128       <para>
5129         Without some (as yet unspecified) help from the compiler, is_stateless will
5130         never report that a class or struct is stateless; this is always safe, if
5131         possibly sub-optimal. Currently (May 2005) only MWCW 9 and Visual C++ 8 have
5132         the necessary compiler <link linkend="boost_typetraits.intrinsics">intrinsics</link>
5133         to make this template work automatically.
5134       </para>
5135     </section>
5136     <section id="boost_typetraits.reference.is_reference"><indexterm type="class_name"><primary>is_reference</primary><secondary>is_reference</secondary></indexterm>
5137       <title><link linkend="boost_typetraits.reference.is_reference"> is_reference</link></title>
5138
5139 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
5140 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_reference</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
5141 </programlisting>
5142       <para>
5143         <emphasis role="bold">Inherits:</emphasis> If T is a reference pointer type
5144         then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
5145         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
5146       </para>
5147       <para>
5148         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.2 and 8.3.2.
5149       </para>
5150       <para>
5151         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
5152         does not support partial-specialization of class templates, then this template
5153         may report the wrong result for function types, and for types that are both
5154         const and volatile qualified.
5155       </para>
5156       <para>
5157         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
5158         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_reference</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5159         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5160       </para>
5161       <para>
5162         <emphasis role="bold">Examples:</emphasis>
5163       </para>
5164       <blockquote>
5165         <para>
5166           <para>
5167             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_reference</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&amp;&gt;</phrase></computeroutput>
5168             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
5169           </para>
5170         </para>
5171       </blockquote>
5172       <blockquote>
5173         <para>
5174           <para>
5175             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_reference</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5176             is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
5177           </para>
5178         </para>
5179       </blockquote>
5180       <blockquote>
5181         <para>
5182           <para>
5183             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_reference</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="special">(&amp;)(</phrase><phrase role="keyword">long</phrase><phrase role="special">)&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
5184             that evaluates to <emphasis>true</emphasis> (the argument in this case
5185             is a reference to a function).
5186           </para>
5187         </para>
5188       </blockquote>
5189       <blockquote>
5190         <para>
5191           <para>
5192             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_reference</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
5193           </para>
5194         </para>
5195       </blockquote>
5196     </section>
5197     <section id="boost_typetraits.reference.is_union"><indexterm type="class_name"><primary>is_union</primary><secondary>is_union</secondary></indexterm>
5198       <title><link linkend="boost_typetraits.reference.is_union"> is_union</link></title>
5199
5200 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
5201 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_union</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
5202 </programlisting>
5203       <para>
5204         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
5205         union type then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
5206         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
5207         Currently requires some kind of compiler support, otherwise unions are identified
5208         as classes.
5209       </para>
5210       <para>
5211         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.2 and 9.5.
5212       </para>
5213       <para>
5214         <emphasis role="bold">Compiler Compatibility:</emphasis> Without (some as
5215         yet unspecified) help from the compiler, we cannot distinguish between union
5216         and class types using only standard C++, as a result this type will never
5217         inherit from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
5218         unless the user explicitly specializes the template for their user-defined
5219         union types, or unless the compiler supplies some unspecified intrinsic that
5220         implements this functionality. Currently (May 2005) only Visual C++ 8 has
5221         the necessary compiler <link linkend="boost_typetraits.intrinsics">intrinsics</link>
5222         to make this trait "just work" without user intervention.
5223       </para>
5224       <para>
5225         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
5226         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_union</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5227         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5228       </para>
5229       <para>
5230         <emphasis role="bold">Examples:</emphasis>
5231       </para>
5232       <blockquote>
5233         <para>
5234           <para>
5235             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_union</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">void</phrase><phrase role="special">&gt;</phrase></computeroutput>
5236             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
5237           </para>
5238         </para>
5239       </blockquote>
5240       <blockquote>
5241         <para>
5242           <para>
5243             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_union</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">const</phrase> <phrase role="keyword">void</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5244             is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
5245           </para>
5246         </para>
5247       </blockquote>
5248       <blockquote>
5249         <para>
5250           <para>
5251             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_union</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">void</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
5252             that evaluates to <emphasis>true</emphasis>.
5253           </para>
5254         </para>
5255       </blockquote>
5256       <blockquote>
5257         <para>
5258           <para>
5259             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_union</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">void</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
5260             that evaluates to <emphasis>false</emphasis>.
5261           </para>
5262         </para>
5263       </blockquote>
5264       <blockquote>
5265         <para>
5266           <para>
5267             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_union</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
5268           </para>
5269         </para>
5270       </blockquote>
5271     </section>
5272     <section id="boost_typetraits.reference.is_unsigned"><indexterm type="class_name"><primary>is_unsigned</primary><secondary>is_unsigned</secondary></indexterm>
5273       <title><link linkend="boost_typetraits.reference.is_unsigned"> is_unsigned</link></title>
5274
5275 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
5276 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_unsigned</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
5277 </programlisting>
5278       <para>
5279         <emphasis role="bold">Inherits:</emphasis> If T is an unsigned integer type
5280         or an enumerated type with an underlying unsigned integer type, then inherits
5281         from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
5282         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
5283       </para>
5284       <para>
5285         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.1, 7.2.
5286       </para>
5287       <para>
5288         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
5289         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_unsigned</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5290         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5291       </para>
5292       <para>
5293         <emphasis role="bold">Examples:</emphasis>
5294       </para>
5295       <blockquote>
5296         <para>
5297           <para>
5298             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_unsigned</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">unsigned</phrase> <phrase role="keyword">int</phrase><phrase role="special">&gt;</phrase></computeroutput> inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
5299           </para>
5300         </para>
5301       </blockquote>
5302       <blockquote>
5303         <para>
5304           <para>
5305             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_unsigned</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">unsigned</phrase> <phrase role="keyword">int</phrase>
5306             <phrase role="keyword">const</phrase> <phrase role="keyword">volatile</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5307             is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
5308           </para>
5309         </para>
5310       </blockquote>
5311       <blockquote>
5312         <para>
5313           <para>
5314             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_unsigned</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
5315             that evaluates to <emphasis>false</emphasis>.
5316           </para>
5317         </para>
5318       </blockquote>
5319       <blockquote>
5320         <para>
5321           <para>
5322             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_unsigned</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">myclass</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
5323             that evaluates to <emphasis>false</emphasis>.
5324           </para>
5325         </para>
5326       </blockquote>
5327       <blockquote>
5328         <para>
5329           <para>
5330             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_unsigned</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">char</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
5331             whose value depends upon the signedness of type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">char</phrase></computeroutput>.
5332           </para>
5333         </para>
5334       </blockquote>
5335       <blockquote>
5336         <para>
5337           <para>
5338             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_unsigned</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">unsigned</phrase> <phrase role="keyword">long</phrase>
5339             <phrase role="keyword">long</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
5340             that evaluates to <emphasis>true</emphasis>.
5341           </para>
5342         </para>
5343       </blockquote>
5344       <blockquote>
5345         <para>
5346           <para>
5347             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_unsigned</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
5348           </para>
5349         </para>
5350       </blockquote>
5351     </section>
5352     <section id="boost_typetraits.reference.is_void"><indexterm type="class_name"><primary>is_void</primary><secondary>is_void</secondary></indexterm>
5353       <title><link linkend="boost_typetraits.reference.is_void"> is_void</link></title>
5354
5355 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
5356 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_void</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
5357 </programlisting>
5358       <para>
5359         <emphasis role="bold">Inherits:</emphasis> If T is a (possibly cv-qualified)
5360         void type then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
5361         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
5362       </para>
5363       <para>
5364         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.1p9.
5365       </para>
5366       <para>
5367         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
5368         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_void</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5369         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5370       </para>
5371       <para>
5372         <emphasis role="bold">Examples:</emphasis>
5373       </para>
5374       <blockquote>
5375         <para>
5376           <para>
5377             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_void</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">void</phrase><phrase role="special">&gt;</phrase></computeroutput>
5378             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
5379           </para>
5380         </para>
5381       </blockquote>
5382       <blockquote>
5383         <para>
5384           <para>
5385             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_void</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">const</phrase> <phrase role="keyword">void</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5386             is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
5387           </para>
5388         </para>
5389       </blockquote>
5390       <blockquote>
5391         <para>
5392           <para>
5393             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_void</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">void</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
5394             that evaluates to <emphasis>true</emphasis>.
5395           </para>
5396         </para>
5397       </blockquote>
5398       <blockquote>
5399         <para>
5400           <para>
5401             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_void</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">void</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
5402             that evaluates to <emphasis>false</emphasis>.
5403           </para>
5404         </para>
5405       </blockquote>
5406       <blockquote>
5407         <para>
5408           <para>
5409             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_void</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
5410           </para>
5411         </para>
5412       </blockquote>
5413     </section>
5414     <section id="boost_typetraits.reference.is_volatile"><indexterm type="class_name"><primary>is_volatile</primary><secondary>is_volatile</secondary></indexterm>
5415       <title><link linkend="boost_typetraits.reference.is_volatile"> is_volatile</link></title>
5416
5417 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
5418 <phrase role="keyword">struct</phrase> <phrase role="identifier">is_volatile</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <replaceable><link linkend="boost_typetraits.reference.integral_constant">true_type</link>-or-<link linkend="boost_typetraits.reference.integral_constant">false_type</link></replaceable> <phrase role="special">{};</phrase>
5419 </programlisting>
5420       <para>
5421         <emphasis role="bold">Inherits:</emphasis> If T is a (top level) volatile-qualified
5422         type then inherits from <link linkend="boost_typetraits.reference.integral_constant">true_type</link>,
5423         otherwise inherits from <link linkend="boost_typetraits.reference.integral_constant">false_type</link>.
5424       </para>
5425       <para>
5426         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.3.
5427       </para>
5428       <para>
5429         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
5430         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">is_volatile</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5431         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5432       </para>
5433       <para>
5434         <emphasis role="bold">Examples:</emphasis>
5435       </para>
5436       <blockquote>
5437         <para>
5438           <para>
5439             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_volatile</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">volatile</phrase> <phrase role="keyword">int</phrase><phrase role="special">&gt;</phrase></computeroutput> inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
5440           </para>
5441         </para>
5442       </blockquote>
5443       <blockquote>
5444         <para>
5445           <para>
5446             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_volatile</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">const</phrase> <phrase role="keyword">volatile</phrase>
5447             <phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">true_type</link></computeroutput>.
5448           </para>
5449         </para>
5450       </blockquote>
5451       <blockquote>
5452         <para>
5453           <para>
5454             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_volatile</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">*</phrase> <phrase role="keyword">volatile</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
5455             that evaluates to <emphasis>true</emphasis>.
5456           </para>
5457         </para>
5458       </blockquote>
5459       <blockquote>
5460         <para>
5461           <para>
5462             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_volatile</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">volatile</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
5463             is an integral constant expression that evaluates to <emphasis>false</emphasis>:
5464             the volatile qualifier is not at the top level in this case.
5465           </para>
5466         </para>
5467       </blockquote>
5468       <blockquote>
5469         <para>
5470           <para>
5471             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">is_volatile</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">bool</phrase></computeroutput>.
5472           </para>
5473         </para>
5474       </blockquote>
5475     </section>
5476     <section id="boost_typetraits.reference.make_signed"><indexterm type="class_name"><primary>make_signed</primary><secondary>make_signed</secondary></indexterm>
5477       <title><link linkend="boost_typetraits.reference.make_signed"> make_signed</link></title>
5478
5479 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
5480 <phrase role="keyword">struct</phrase> <phrase role="identifier">make_signed</phrase>
5481 <phrase role="special">{</phrase>
5482    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
5483 <phrase role="special">};</phrase>
5484 </programlisting>
5485       <para>
5486         <emphasis role="bold">type:</emphasis> If T is a signed integer type then
5487         the same type as T, if T is an unsigned integer type then the corresponding
5488         signed type. Otherwise if T is an enumerated or character type (char or wchar_t)
5489         then a signed integer type with the same width as T.
5490       </para>
5491       <para>
5492         If T has any cv-qualifiers then these are also present on the result type.
5493       </para>
5494       <para>
5495         <emphasis role="bold">Requires:</emphasis> T must be an integer or enumerated
5496         type, and must not be the type bool.
5497       </para>
5498       <para>
5499         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.1.
5500       </para>
5501       <para>
5502         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
5503         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">make_signed</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5504         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5505       </para>
5506       <table frame="all"> <title>Examples</title>
5507       <tgroup cols="2">
5508         <thead>
5509           <row>
5510             <entry>
5511             <para>
5512               Expression
5513             </para>
5514             </entry><entry>
5515             <para>
5516               Result Type
5517             </para>
5518             </entry>
5519           </row>
5520         </thead>
5521         <tbody>
5522           <row>
5523             <entry>
5524             <para>
5525               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">make_signed</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5526             </para>
5527             </entry><entry>
5528             <para>
5529               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase></computeroutput>
5530             </para>
5531             </entry>
5532           </row>
5533           <row>
5534             <entry>
5535             <para>
5536               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">make_signed</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">unsigned</phrase> <phrase role="keyword">int</phrase>
5537               <phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5538             </para>
5539             </entry><entry>
5540             <para>
5541               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase></computeroutput>
5542             </para>
5543             </entry>
5544           </row>
5545           <row>
5546             <entry>
5547             <para>
5548               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">make_signed</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">const</phrase> <phrase role="keyword">unsigned</phrase>
5549               <phrase role="keyword">long</phrase> <phrase role="keyword">long</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5550             </para>
5551             </entry><entry>
5552             <para>
5553               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">const</phrase> <phrase role="keyword">long</phrase>
5554               <phrase role="keyword">long</phrase></computeroutput>
5555             </para>
5556             </entry>
5557           </row>
5558           <row>
5559             <entry>
5560             <para>
5561               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">make_signed</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">my_enum</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5562             </para>
5563             </entry><entry>
5564             <para>
5565               A signed integer type with the same width as the enum.
5566             </para>
5567             </entry>
5568           </row>
5569           <row>
5570             <entry>
5571             <para>
5572               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">make_signed</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">wchar_t</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5573             </para>
5574             </entry><entry>
5575             <para>
5576               A signed integer type with the same width as wchar_t.
5577             </para>
5578             </entry>
5579           </row>
5580         </tbody>
5581       </tgroup>
5582       </table>
5583     </section>
5584     <section id="boost_typetraits.reference.make_unsigned"><indexterm type="class_name"><primary>make_unsigned</primary><secondary>make_unsigned</secondary></indexterm>
5585       <title><link linkend="boost_typetraits.reference.make_unsigned"> make_unsigned</link></title>
5586
5587 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
5588 <phrase role="keyword">struct</phrase> <phrase role="identifier">make_unsigned</phrase>
5589 <phrase role="special">{</phrase>
5590    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
5591 <phrase role="special">};</phrase>
5592 </programlisting>
5593       <para>
5594         <emphasis role="bold">type:</emphasis> If T is a unsigned integer type then
5595         the same type as T, if T is an signed integer type then the corresponding
5596         unsigned type. Otherwise if T is an enumerated or character type (char or
5597         wchar_t) then an unsigned integer type with the same width as T.
5598       </para>
5599       <para>
5600         If T has any cv-qualifiers then these are also present on the result type.
5601       </para>
5602       <para>
5603         <emphasis role="bold">Requires:</emphasis> T must be an integer or enumerated
5604         type, and must not be the type bool.
5605       </para>
5606       <para>
5607         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.1.
5608       </para>
5609       <para>
5610         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
5611         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">make_unsigned</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5612         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5613       </para>
5614       <table frame="all"> <title>Examples</title>
5615       <tgroup cols="2">
5616         <thead>
5617           <row>
5618             <entry>
5619             <para>
5620               Expression
5621             </para>
5622             </entry><entry>
5623             <para>
5624               Result Type
5625             </para>
5626             </entry>
5627           </row>
5628         </thead>
5629         <tbody>
5630           <row>
5631             <entry>
5632             <para>
5633               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">make_signed</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5634             </para>
5635             </entry><entry>
5636             <para>
5637               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">unsigned</phrase> <phrase role="keyword">int</phrase></computeroutput>
5638             </para>
5639             </entry>
5640           </row>
5641           <row>
5642             <entry>
5643             <para>
5644               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">make_signed</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">unsigned</phrase> <phrase role="keyword">int</phrase>
5645               <phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5646             </para>
5647             </entry><entry>
5648             <para>
5649               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">unsigned</phrase> <phrase role="keyword">int</phrase>
5650               <phrase role="keyword">const</phrase></computeroutput>
5651             </para>
5652             </entry>
5653           </row>
5654           <row>
5655             <entry>
5656             <para>
5657               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">make_signed</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">const</phrase> <phrase role="keyword">unsigned</phrase>
5658               <phrase role="keyword">long</phrase> <phrase role="keyword">long</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5659             </para>
5660             </entry><entry>
5661             <para>
5662               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">const</phrase> <phrase role="keyword">unsigned</phrase>
5663               <phrase role="keyword">long</phrase> <phrase role="keyword">long</phrase></computeroutput>
5664             </para>
5665             </entry>
5666           </row>
5667           <row>
5668             <entry>
5669             <para>
5670               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">make_signed</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">my_enum</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5671             </para>
5672             </entry><entry>
5673             <para>
5674               An unsigned integer type with the same width as the enum.
5675             </para>
5676             </entry>
5677           </row>
5678           <row>
5679             <entry>
5680             <para>
5681               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">make_signed</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">wchar_t</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5682             </para>
5683             </entry><entry>
5684             <para>
5685               An unsigned integer type with the same width as wchar_t.
5686             </para>
5687             </entry>
5688           </row>
5689         </tbody>
5690       </tgroup>
5691       </table>
5692     </section>
5693     <section id="boost_typetraits.reference.promote"><indexterm type="class_name"><primary>promote</primary><secondary>promote</secondary></indexterm>
5694       <title><link linkend="boost_typetraits.reference.promote"> promote</link></title>
5695
5696 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
5697 <phrase role="keyword">struct</phrase> <phrase role="identifier">promote</phrase>
5698 <phrase role="special">{</phrase>
5699    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
5700 <phrase role="special">};</phrase>
5701 </programlisting>
5702       <para>
5703         <emphasis role="bold">type:</emphasis> If integral or floating point promotion
5704         can be applied to an rvalue of type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>,
5705         then applies integral and floating point promotions to <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>
5706         and keeps cv-qualifiers of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>,
5707         otherwise leaves <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput> unchanged.
5708         See also <link linkend="boost_typetraits.reference.integral_promotion">integral_promotion</link>
5709         and <link linkend="boost_typetraits.reference.floating_point_promotion">floating_point_promotion</link>.
5710       </para>
5711       <para>
5712         <emphasis role="bold">C++ Standard Reference:</emphasis> 4.5 except 4.5/3
5713         (integral bit-field) and 4.6.
5714       </para>
5715       <para>
5716         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
5717         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">promote</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5718         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5719       </para>
5720       <table frame="all"> <title>Examples</title>
5721       <tgroup cols="2">
5722         <thead>
5723           <row>
5724             <entry>
5725             <para>
5726               Expression
5727             </para>
5728             </entry><entry>
5729             <para>
5730               Result Type
5731             </para>
5732             </entry>
5733           </row>
5734         </thead>
5735         <tbody>
5736           <row>
5737             <entry>
5738             <para>
5739               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">promote</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">short</phrase> <phrase role="keyword">volatile</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5740             </para>
5741             </entry><entry>
5742             <para>
5743               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">volatile</phrase></computeroutput>
5744             </para>
5745             </entry>
5746           </row>
5747           <row>
5748             <entry>
5749             <para>
5750               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">promote</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">float</phrase> <phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5751             </para>
5752             </entry><entry>
5753             <para>
5754               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">double</phrase> <phrase role="keyword">const</phrase></computeroutput>
5755             </para>
5756             </entry>
5757           </row>
5758           <row>
5759             <entry>
5760             <para>
5761               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">promote</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">short</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5762             </para>
5763             </entry><entry>
5764             <para>
5765               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">short</phrase><phrase role="special">&amp;</phrase></computeroutput>
5766             </para>
5767             </entry>
5768           </row>
5769         </tbody>
5770       </tgroup>
5771       </table>
5772     </section>
5773     <section id="boost_typetraits.reference.rank"><indexterm type="class_name"><primary>integral_constant</primary><secondary>rank</secondary></indexterm><indexterm><primary>rank</primary><secondary>integral_constant</secondary></indexterm>
5774       <title><link linkend="boost_typetraits.reference.rank"> rank</link></title>
5775
5776 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
5777 <phrase role="keyword">struct</phrase> <phrase role="identifier">rank</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <link linkend="boost_typetraits.reference.integral_constant">integral_constant</link><phrase role="special">&lt;</phrase><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase><phrase role="special">,</phrase> <phrase role="identifier">RANK</phrase><phrase role="special">(</phrase><phrase role="identifier">T</phrase><phrase role="special">)&gt;</phrase> <phrase role="special">{};</phrase>
5778 </programlisting>
5779       <para>
5780         <emphasis role="bold">Inherits:</emphasis> Class template rank inherits from
5781         <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">integral_constant</link><phrase role="special">&lt;</phrase><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase><phrase role="special">,</phrase> <phrase role="identifier">RANK</phrase><phrase role="special">(</phrase><phrase role="identifier">T</phrase><phrase role="special">)&gt;</phrase></computeroutput>,
5782         where <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">RANK</phrase><phrase role="special">(</phrase><phrase role="identifier">T</phrase><phrase role="special">)</phrase></computeroutput> is the
5783         number of array dimensions in type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>.
5784       </para>
5785       <para>
5786         If <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput> is not an array type,
5787         then <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">RANK</phrase><phrase role="special">(</phrase><phrase role="identifier">T</phrase><phrase role="special">)</phrase></computeroutput> is zero.
5788       </para>
5789       <para>
5790         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
5791         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">rank</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5792         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5793       </para>
5794       <para>
5795         <emphasis role="bold">Examples:</emphasis>
5796       </para>
5797       <blockquote>
5798         <para>
5799           <para>
5800             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">rank</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">[]&gt;</phrase></computeroutput>
5801             inherits from <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">integral_constant</link><phrase role="special">&lt;</phrase><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase><phrase role="special">,</phrase> <phrase role="number">1</phrase><phrase role="special">&gt;</phrase></computeroutput>.
5802           </para>
5803         </para>
5804       </blockquote>
5805       <blockquote>
5806         <para>
5807           <para>
5808             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">rank</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">double</phrase><phrase role="special">[</phrase><phrase role="number">2</phrase><phrase role="special">][</phrase><phrase role="number">3</phrase><phrase role="special">][</phrase><phrase role="number">4</phrase><phrase role="special">]&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><link linkend="boost_typetraits.reference.integral_constant">integral_constant</link><phrase role="special">&lt;</phrase><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase><phrase role="special">,</phrase> <phrase role="number">3</phrase><phrase role="special">&gt;</phrase></computeroutput>.
5809           </para>
5810         </para>
5811       </blockquote>
5812       <blockquote>
5813         <para>
5814           <para>
5815             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">rank</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">[</phrase><phrase role="number">1</phrase><phrase role="special">]&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput>
5816             is an integral constant expression that evaluates to <emphasis>1</emphasis>.
5817           </para>
5818         </para>
5819       </blockquote>
5820       <blockquote>
5821         <para>
5822           <para>
5823             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">rank</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">[][</phrase><phrase role="number">2</phrase><phrase role="special">]&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
5824             that evaluates to <emphasis>2</emphasis>.
5825           </para>
5826         </para>
5827       </blockquote>
5828       <blockquote>
5829         <para>
5830           <para>
5831             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">rank</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">value</phrase></computeroutput> is an integral constant expression
5832             that evaluates to <emphasis>0</emphasis>.
5833           </para>
5834         </para>
5835       </blockquote>
5836       <blockquote>
5837         <para>
5838           <para>
5839             <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">rank</phrase><phrase role="special">&lt;</phrase><phrase role="identifier">T</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">value_type</phrase></computeroutput> is the type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase></computeroutput>.
5840           </para>
5841         </para>
5842       </blockquote>
5843     </section>
5844     <section id="boost_typetraits.reference.remove_all_extents"><indexterm type="class_name"><primary>remove_all_extents</primary><secondary>remove_all_extents</secondary></indexterm>
5845       <title><link linkend="boost_typetraits.reference.remove_all_extents"> remove_all_extents</link></title>
5846
5847 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
5848 <phrase role="keyword">struct</phrase> <phrase role="identifier">remove_all_extents</phrase>
5849 <phrase role="special">{</phrase>
5850    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
5851 <phrase role="special">};</phrase>
5852 </programlisting>
5853       <para>
5854         <emphasis role="bold">type:</emphasis> If <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>
5855         is an array type, then removes all of the array bounds on <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>,
5856         otherwise leaves <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput> unchanged.
5857       </para>
5858       <para>
5859         <emphasis role="bold">C++ Standard Reference:</emphasis> 8.3.4.
5860       </para>
5861       <para>
5862         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
5863         does not support partial specialization of class-templates then this template
5864         will compile, but the member <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">type</phrase></computeroutput>
5865         will always be the same as type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>
5866         except where <link linkend="boost_typetraits.category.transform.broken_compiler_workarounds_">compiler
5867         workarounds</link> have been applied.
5868       </para>
5869       <para>
5870         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
5871         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">remove_all_extents</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5872         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5873       </para>
5874       <table frame="all"> <title>Examples</title>
5875       <tgroup cols="2">
5876         <thead>
5877           <row>
5878             <entry>
5879             <para>
5880               Expression
5881             </para>
5882             </entry><entry>
5883             <para>
5884               Result Type
5885             </para>
5886             </entry>
5887           </row>
5888         </thead>
5889         <tbody>
5890           <row>
5891             <entry>
5892             <para>
5893               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_all_extents</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5894             </para>
5895             </entry><entry>
5896             <para>
5897               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase></computeroutput>
5898             </para>
5899             </entry>
5900           </row>
5901           <row>
5902             <entry>
5903             <para>
5904               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_all_extents</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">[</phrase><phrase role="number">2</phrase><phrase role="special">]&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5905             </para>
5906             </entry><entry>
5907             <para>
5908               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase></computeroutput>
5909             </para>
5910             </entry>
5911           </row>
5912           <row>
5913             <entry>
5914             <para>
5915               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_all_extents</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">[][</phrase><phrase role="number">2</phrase><phrase role="special">]&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5916             </para>
5917             </entry><entry>
5918             <para>
5919               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase></computeroutput>
5920             </para>
5921             </entry>
5922           </row>
5923           <row>
5924             <entry>
5925             <para>
5926               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_all_extents</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">[</phrase><phrase role="number">2</phrase><phrase role="special">][</phrase><phrase role="number">3</phrase><phrase role="special">][</phrase><phrase role="number">4</phrase><phrase role="special">]&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5927             </para>
5928             </entry><entry>
5929             <para>
5930               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase></computeroutput>
5931             </para>
5932             </entry>
5933           </row>
5934           <row>
5935             <entry>
5936             <para>
5937               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_all_extents</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5938             </para>
5939             </entry><entry>
5940             <para>
5941               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">*</phrase></computeroutput>
5942             </para>
5943             </entry>
5944           </row>
5945         </tbody>
5946       </tgroup>
5947       </table>
5948     </section>
5949     <section id="boost_typetraits.reference.remove_const"><indexterm type="class_name"><primary>remove_const</primary><secondary>remove_const</secondary></indexterm>
5950       <title><link linkend="boost_typetraits.reference.remove_const"> remove_const</link></title>
5951
5952 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
5953 <phrase role="keyword">struct</phrase> <phrase role="identifier">remove_const</phrase>
5954 <phrase role="special">{</phrase>
5955    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
5956 <phrase role="special">};</phrase>
5957 </programlisting>
5958       <para>
5959         <emphasis role="bold">type:</emphasis> The same type as <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>,
5960         but with any <emphasis>top level</emphasis> const-qualifier removed.
5961       </para>
5962       <para>
5963         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.3.
5964       </para>
5965       <para>
5966         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
5967         does not support partial specialization of class-templates then this template
5968         will compile, but the member <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">type</phrase></computeroutput>
5969         will always be the same as type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>
5970         except where <link linkend="boost_typetraits.category.transform.broken_compiler_workarounds_">compiler
5971         workarounds</link> have been applied.
5972       </para>
5973       <para>
5974         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
5975         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">remove_const</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5976         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
5977       </para>
5978       <table frame="all"> <title>Examples</title>
5979       <tgroup cols="2">
5980         <thead>
5981           <row>
5982             <entry>
5983             <para>
5984               Expression
5985             </para>
5986             </entry><entry>
5987             <para>
5988               Result Type
5989             </para>
5990             </entry>
5991           </row>
5992         </thead>
5993         <tbody>
5994           <row>
5995             <entry>
5996             <para>
5997               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_const</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
5998             </para>
5999             </entry><entry>
6000             <para>
6001               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase></computeroutput>
6002             </para>
6003             </entry>
6004           </row>
6005           <row>
6006             <entry>
6007             <para>
6008               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_const</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6009             </para>
6010             </entry><entry>
6011             <para>
6012               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase></computeroutput>
6013             </para>
6014             </entry>
6015           </row>
6016           <row>
6017             <entry>
6018             <para>
6019               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_const</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase>
6020               <phrase role="keyword">volatile</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6021             </para>
6022             </entry><entry>
6023             <para>
6024               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">volatile</phrase></computeroutput>
6025             </para>
6026             </entry>
6027           </row>
6028           <row>
6029             <entry>
6030             <para>
6031               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_const</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6032             </para>
6033             </entry><entry>
6034             <para>
6035               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">&amp;</phrase></computeroutput>
6036             </para>
6037             </entry>
6038           </row>
6039           <row>
6040             <entry>
6041             <para>
6042               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_const</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6043             </para>
6044             </entry><entry>
6045             <para>
6046               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">*</phrase></computeroutput>
6047             </para>
6048             </entry>
6049           </row>
6050         </tbody>
6051       </tgroup>
6052       </table>
6053     </section>
6054     <section id="boost_typetraits.reference.remove_cv"><indexterm type="class_name"><primary>remove_cv</primary><secondary>remove_cv</secondary></indexterm>
6055       <title><link linkend="boost_typetraits.reference.remove_cv"> remove_cv</link></title>
6056
6057 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
6058 <phrase role="keyword">struct</phrase> <phrase role="identifier">remove_cv</phrase>
6059 <phrase role="special">{</phrase>
6060    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
6061 <phrase role="special">};</phrase>
6062 </programlisting>
6063       <para>
6064         <emphasis role="bold">type:</emphasis> The same type as <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>,
6065         but with any <emphasis>top level</emphasis> cv-qualifiers removed.
6066       </para>
6067       <para>
6068         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.3.
6069       </para>
6070       <para>
6071         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
6072         does not support partial specialization of class-templates then this template
6073         will compile, but the member <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">type</phrase></computeroutput>
6074         will always be the same as type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>
6075         except where <link linkend="boost_typetraits.category.transform.broken_compiler_workarounds_">compiler
6076         workarounds</link> have been applied.
6077       </para>
6078       <para>
6079         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
6080         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">remove_cv</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
6081         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
6082       </para>
6083       <table frame="all"> <title>Examples</title>
6084       <tgroup cols="2">
6085         <thead>
6086           <row>
6087             <entry>
6088             <para>
6089               Expression
6090             </para>
6091             </entry><entry>
6092             <para>
6093               Result Type
6094             </para>
6095             </entry>
6096           </row>
6097         </thead>
6098         <tbody>
6099           <row>
6100             <entry>
6101             <para>
6102               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_cv</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6103             </para>
6104             </entry><entry>
6105             <para>
6106               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase></computeroutput>
6107             </para>
6108             </entry>
6109           </row>
6110           <row>
6111             <entry>
6112             <para>
6113               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_cv</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6114             </para>
6115             </entry><entry>
6116             <para>
6117               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase></computeroutput>
6118             </para>
6119             </entry>
6120           </row>
6121           <row>
6122             <entry>
6123             <para>
6124               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_cv</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase>
6125               <phrase role="keyword">volatile</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6126             </para>
6127             </entry><entry>
6128             <para>
6129               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase></computeroutput>
6130             </para>
6131             </entry>
6132           </row>
6133           <row>
6134             <entry>
6135             <para>
6136               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_cv</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6137             </para>
6138             </entry><entry>
6139             <para>
6140               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">&amp;</phrase></computeroutput>
6141             </para>
6142             </entry>
6143           </row>
6144           <row>
6145             <entry>
6146             <para>
6147               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_cv</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6148             </para>
6149             </entry><entry>
6150             <para>
6151               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">*</phrase></computeroutput>
6152             </para>
6153             </entry>
6154           </row>
6155         </tbody>
6156       </tgroup>
6157       </table>
6158     </section>
6159     <section id="boost_typetraits.reference.remove_extent"><indexterm type="class_name"><primary>remove_extent</primary><secondary>remove_extent</secondary></indexterm>
6160       <title><link linkend="boost_typetraits.reference.remove_extent"> remove_extent</link></title>
6161
6162 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
6163 <phrase role="keyword">struct</phrase> <phrase role="identifier">remove_extent</phrase>
6164 <phrase role="special">{</phrase>
6165    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
6166 <phrase role="special">};</phrase>
6167 </programlisting>
6168       <para>
6169         <emphasis role="bold">type:</emphasis> If <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>
6170         is an array type, then removes the topmost array bound, otherwise leaves
6171         <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput> unchanged.
6172       </para>
6173       <para>
6174         <emphasis role="bold">C++ Standard Reference:</emphasis> 8.3.4.
6175       </para>
6176       <para>
6177         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
6178         does not support partial specialization of class-templates then this template
6179         will compile, but the member <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">type</phrase></computeroutput>
6180         will always be the same as type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>
6181         except where <link linkend="boost_typetraits.category.transform.broken_compiler_workarounds_">compiler
6182         workarounds</link> have been applied.
6183       </para>
6184       <para>
6185         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
6186         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">remove_extent</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
6187         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
6188       </para>
6189       <table frame="all"> <title>Examples</title>
6190       <tgroup cols="2">
6191         <thead>
6192           <row>
6193             <entry>
6194             <para>
6195               Expression
6196             </para>
6197             </entry><entry>
6198             <para>
6199               Result Type
6200             </para>
6201             </entry>
6202           </row>
6203         </thead>
6204         <tbody>
6205           <row>
6206             <entry>
6207             <para>
6208               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_extent</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6209             </para>
6210             </entry><entry>
6211             <para>
6212               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase></computeroutput>
6213             </para>
6214             </entry>
6215           </row>
6216           <row>
6217             <entry>
6218             <para>
6219               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_extent</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">[</phrase><phrase role="number">2</phrase><phrase role="special">]&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6220             </para>
6221             </entry><entry>
6222             <para>
6223               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase></computeroutput>
6224             </para>
6225             </entry>
6226           </row>
6227           <row>
6228             <entry>
6229             <para>
6230               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_extent</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">[</phrase><phrase role="number">2</phrase><phrase role="special">][</phrase><phrase role="number">4</phrase><phrase role="special">]&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6231             </para>
6232             </entry><entry>
6233             <para>
6234               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">[</phrase><phrase role="number">4</phrase><phrase role="special">]</phrase></computeroutput>
6235             </para>
6236             </entry>
6237           </row>
6238           <row>
6239             <entry>
6240             <para>
6241               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_extent</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">[][</phrase><phrase role="number">2</phrase><phrase role="special">]&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6242             </para>
6243             </entry><entry>
6244             <para>
6245               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">[</phrase><phrase role="number">2</phrase><phrase role="special">]</phrase></computeroutput>
6246             </para>
6247             </entry>
6248           </row>
6249           <row>
6250             <entry>
6251             <para>
6252               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_extent</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6253             </para>
6254             </entry><entry>
6255             <para>
6256               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">*</phrase></computeroutput>
6257             </para>
6258             </entry>
6259           </row>
6260         </tbody>
6261       </tgroup>
6262       </table>
6263     </section>
6264     <section id="boost_typetraits.reference.remove_pointer"><indexterm type="class_name"><primary>remove_pointer</primary><secondary>remove_pointer</secondary></indexterm>
6265       <title><link linkend="boost_typetraits.reference.remove_pointer"> remove_pointer</link></title>
6266
6267 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
6268 <phrase role="keyword">struct</phrase> <phrase role="identifier">remove_pointer</phrase>
6269 <phrase role="special">{</phrase>
6270    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
6271 <phrase role="special">};</phrase>
6272 </programlisting>
6273       <para>
6274         <emphasis role="bold">type:</emphasis> The same type as <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>,
6275         but with any pointer modifier removed.
6276       </para>
6277       <para>
6278         <emphasis role="bold">C++ Standard Reference:</emphasis> 8.3.1.
6279       </para>
6280       <para>
6281         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
6282         does not support partial specialization of class-templates then this template
6283         will compile, but the member <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">type</phrase></computeroutput>
6284         will always be the same as type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>
6285         except where <link linkend="boost_typetraits.category.transform.broken_compiler_workarounds_">compiler
6286         workarounds</link> have been applied.
6287       </para>
6288       <para>
6289         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
6290         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">remove_pointer</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
6291         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
6292       </para>
6293       <table frame="all"> <title>Examples</title>
6294       <tgroup cols="2">
6295         <thead>
6296           <row>
6297             <entry>
6298             <para>
6299               Expression
6300             </para>
6301             </entry><entry>
6302             <para>
6303               Result Type
6304             </para>
6305             </entry>
6306           </row>
6307         </thead>
6308         <tbody>
6309           <row>
6310             <entry>
6311             <para>
6312               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6313             </para>
6314             </entry><entry>
6315             <para>
6316               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase></computeroutput>
6317             </para>
6318             </entry>
6319           </row>
6320           <row>
6321             <entry>
6322             <para>
6323               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6324             </para>
6325             </entry><entry>
6326             <para>
6327               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase></computeroutput>
6328             </para>
6329             </entry>
6330           </row>
6331           <row>
6332             <entry>
6333             <para>
6334               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">**&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6335             </para>
6336             </entry><entry>
6337             <para>
6338               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">*</phrase></computeroutput>
6339             </para>
6340             </entry>
6341           </row>
6342           <row>
6343             <entry>
6344             <para>
6345               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6346             </para>
6347             </entry><entry>
6348             <para>
6349               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">&amp;</phrase></computeroutput>
6350             </para>
6351             </entry>
6352           </row>
6353           <row>
6354             <entry>
6355             <para>
6356               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_pointer</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">*&amp;&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6357             </para>
6358             </entry><entry>
6359             <para>
6360               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">*&amp;</phrase></computeroutput>
6361             </para>
6362             </entry>
6363           </row>
6364         </tbody>
6365       </tgroup>
6366       </table>
6367     </section>
6368     <section id="boost_typetraits.reference.remove_reference"><indexterm type="class_name"><primary>remove_reference</primary><secondary>remove_reference</secondary></indexterm>
6369       <title><link linkend="boost_typetraits.reference.remove_reference"> remove_reference</link></title>
6370
6371 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
6372 <phrase role="keyword">struct</phrase> <phrase role="identifier">remove_reference</phrase>
6373 <phrase role="special">{</phrase>
6374    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
6375 <phrase role="special">};</phrase>
6376 </programlisting>
6377       <para>
6378         <emphasis role="bold">type:</emphasis> The same type as <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>,
6379         but with any reference modifier removed.
6380       </para>
6381       <para>
6382         <emphasis role="bold">C++ Standard Reference:</emphasis> 8.3.2.
6383       </para>
6384       <para>
6385         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
6386         does not support partial specialization of class-templates then this template
6387         will compile, but the member <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">type</phrase></computeroutput>
6388         will always be the same as type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>
6389         except where <link linkend="boost_typetraits.category.transform.broken_compiler_workarounds_">compiler
6390         workarounds</link> have been applied.
6391       </para>
6392       <para>
6393         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
6394         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">remove_reference</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
6395         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
6396       </para>
6397       <table frame="all"> <title>Examples</title>
6398       <tgroup cols="2">
6399         <thead>
6400           <row>
6401             <entry>
6402             <para>
6403               Expression
6404             </para>
6405             </entry><entry>
6406             <para>
6407               Result Type
6408             </para>
6409             </entry>
6410           </row>
6411         </thead>
6412         <tbody>
6413           <row>
6414             <entry>
6415             <para>
6416               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_reference</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6417             </para>
6418             </entry><entry>
6419             <para>
6420               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase></computeroutput>
6421             </para>
6422             </entry>
6423           </row>
6424           <row>
6425             <entry>
6426             <para>
6427               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_reference</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6428             </para>
6429             </entry><entry>
6430             <para>
6431               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase></computeroutput>
6432             </para>
6433             </entry>
6434           </row>
6435           <row>
6436             <entry>
6437             <para>
6438               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_reference</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6439             </para>
6440             </entry><entry>
6441             <para>
6442               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">*</phrase></computeroutput>
6443             </para>
6444             </entry>
6445           </row>
6446           <row>
6447             <entry>
6448             <para>
6449               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_reference</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">*&amp;&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6450             </para>
6451             </entry><entry>
6452             <para>
6453               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase><phrase role="special">*</phrase></computeroutput>
6454             </para>
6455             </entry>
6456           </row>
6457         </tbody>
6458       </tgroup>
6459       </table>
6460     </section>
6461     <section id="boost_typetraits.reference.remove_volatile"><indexterm type="class_name"><primary>remove_volatile</primary><secondary>remove_volatile</secondary></indexterm>
6462       <title><link linkend="boost_typetraits.reference.remove_volatile"> remove_volatile</link></title>
6463
6464 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
6465 <phrase role="keyword">struct</phrase> <phrase role="identifier">remove_volatile</phrase>
6466 <phrase role="special">{</phrase>
6467    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
6468 <phrase role="special">};</phrase>
6469 </programlisting>
6470       <para>
6471         <emphasis role="bold">type:</emphasis> The same type as <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>,
6472         but with any <emphasis>top level</emphasis> volatile-qualifier removed.
6473       </para>
6474       <para>
6475         <emphasis role="bold">C++ Standard Reference:</emphasis> 3.9.3.
6476       </para>
6477       <para>
6478         <emphasis role="bold">Compiler Compatibility:</emphasis> If the compiler
6479         does not support partial specialization of class-templates then this template
6480         will compile, but the member <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">type</phrase></computeroutput>
6481         will always be the same as type <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">T</phrase></computeroutput>
6482         except where <link linkend="boost_typetraits.category.transform.broken_compiler_workarounds_">compiler
6483         workarounds</link> have been applied.
6484       </para>
6485       <para>
6486         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
6487         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">remove_volatile</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
6488         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
6489       </para>
6490       <table frame="all"> <title>Examples</title>
6491       <tgroup cols="2">
6492         <thead>
6493           <row>
6494             <entry>
6495             <para>
6496               Expression
6497             </para>
6498             </entry><entry>
6499             <para>
6500               Result Type
6501             </para>
6502             </entry>
6503           </row>
6504         </thead>
6505         <tbody>
6506           <row>
6507             <entry>
6508             <para>
6509               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_volatile</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6510             </para>
6511             </entry><entry>
6512             <para>
6513               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase></computeroutput>
6514             </para>
6515             </entry>
6516           </row>
6517           <row>
6518             <entry>
6519             <para>
6520               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_volatile</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">volatile</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6521             </para>
6522             </entry><entry>
6523             <para>
6524               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase></computeroutput>
6525             </para>
6526             </entry>
6527           </row>
6528           <row>
6529             <entry>
6530             <para>
6531               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_volatile</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase>
6532               <phrase role="keyword">volatile</phrase><phrase role="special">&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6533             </para>
6534             </entry><entry>
6535             <para>
6536               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase></computeroutput>
6537             </para>
6538             </entry>
6539           </row>
6540           <row>
6541             <entry>
6542             <para>
6543               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_volatile</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">volatile</phrase><phrase role="special">&amp;&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6544             </para>
6545             </entry><entry>
6546             <para>
6547               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">&amp;</phrase></computeroutput>
6548             </para>
6549             </entry>
6550           </row>
6551           <row>
6552             <entry>
6553             <para>
6554               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">remove_volatile</phrase><phrase role="special">&lt;</phrase><phrase role="keyword">int</phrase> <phrase role="keyword">volatile</phrase><phrase role="special">*&gt;::</phrase><phrase role="identifier">type</phrase></computeroutput>
6555             </para>
6556             </entry><entry>
6557             <para>
6558               <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">int</phrase> <phrase role="keyword">const</phrase><phrase role="special">*</phrase></computeroutput>
6559             </para>
6560             </entry>
6561           </row>
6562         </tbody>
6563       </tgroup>
6564       </table>
6565     </section>
6566     <section id="boost_typetraits.reference.type_with_alignment"><indexterm type="class_name"><primary>type_with_alignment</primary><secondary>type_with_alignment</secondary></indexterm>
6567       <title><link linkend="boost_typetraits.reference.type_with_alignment"> type_with_alignment</link></title>
6568
6569 <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">Align</phrase><phrase role="special">&gt;</phrase>
6570 <phrase role="keyword">struct</phrase> <phrase role="identifier">type_with_alignment</phrase>
6571 <phrase role="special">{</phrase>
6572    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
6573 <phrase role="special">};</phrase>
6574 </programlisting>
6575       <para>
6576         <emphasis role="bold">type:</emphasis> a built-in or POD type with an alignment
6577         that is a multiple of <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="identifier">Align</phrase></computeroutput>.
6578       </para>
6579       <para>
6580         <emphasis role="bold">Header:</emphasis> <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase>
6581         <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">/</phrase><phrase role="identifier">type_with_alignment</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
6582         or <computeroutput xmlns:xi="http://www.w3.org/2001/XInclude"> <phrase role="preprocessor">#include</phrase> <phrase role="special">&lt;</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">type_traits</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">&gt;</phrase></computeroutput>
6583       </para>
6584     </section>
6585   </section>
6586   <section id="boost_typetraits.credits">
6587     <title><link linkend="boost_typetraits.credits"> Credits</link></title>
6588     <para>
6589       This documentation was pulled together by John Maddock, using <ulink url="../../../../doc/html/quickbook.html">Boost.Quickbook</ulink>
6590       and <ulink url="../../../../doc/html/boostbook.html">Boost.DocBook</ulink>.
6591     </para>
6592     <para>
6593       The original version of this library was created by Steve Cleary, Beman Dawes,
6594       Howard Hinnant, and John Maddock. John Maddock is the current maintainer of
6595       the library.
6596     </para>
6597     <para>
6598       This version of type traits library is based on contributions by Adobe Systems
6599       Inc, David Abrahams, Steve Cleary, Beman Dawes, Aleksey Gurtovoy, Howard Hinnant,
6600       Jesse Jones, Mat Marcus, Itay Maman, John Maddock, Thorsten Ottosen, Robert
6601       Ramey and Jeremy Siek.
6602     </para>
6603     <para>
6604       Mat Marcus and Jesse Jones invented, and <ulink url="http://opensource.adobe.com/project4/project.shtml">published
6605       a paper describing</ulink>, the partial specialization workarounds used in
6606       this library.
6607     </para>
6608     <para>
6609       Aleksey Gurtovoy added MPL integration to the library.
6610     </para>
6611     <para>
6612       The <link linkend="boost_typetraits.reference.is_convertible">is_convertible</link>
6613       template is based on code originally devised by Andrei Alexandrescu, see "<ulink url="http://www.cuj.com/experts/1810/alexandr.htm?topic=experts">Generic&lt;Programming&gt;:
6614       Mappings between Types and Values</ulink>".
6615     </para>
6616     <para>
6617       The latest version of this library and documentation can be found at <ulink url="http://www.boost.org">www.boost.org</ulink>. Bugs, suggestions and discussion
6618       should be directed to boost@lists.boost.org (see <ulink url="http://www.boost.org/more/mailing_lists.htm#main">www.boost.org/more/mailing_lists.htm#main</ulink>
6619       for subscription details).
6620     </para>
6621   </section>
6622
6623   <section id="boost_typetraits.ignored_section">
6624     <title>This section must not be indexed.</title>
6625      <?BoostAutoIndex IgnoreSection?>
6626        <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
6627 <phrase role="keyword">struct</phrase> <phrase role="identifier">add_const</phrase>
6628 <phrase role="special">{</phrase>
6629    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
6630 <phrase role="special">};</phrase>
6631 </programlisting>
6632   </section>
6633
6634   <section id="boost_typetraits.ignored_block"><indexterm type="class_name"><primary>add_volatile</primary><secondary>This section contains one block that must not be indexed and one that should be.</secondary></indexterm><indexterm><primary>This section contains one block that must not be indexed and one that should be.</primary><secondary>add_volatile</secondary></indexterm>
6635     <title>This section contains one block that must not be indexed and one that should be.</title>
6636        <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">
6637      <?BoostAutoIndex IgnoreBlock?>
6638           template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
6639 <phrase role="keyword">struct</phrase> <phrase role="identifier">add_const</phrase>
6640 <phrase role="special">{</phrase>
6641    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
6642 <phrase role="special">};</phrase>
6643 </programlisting>
6644        <programlisting xmlns:xi="http://www.w3.org/2001/XInclude"><phrase role="keyword">
6645           template</phrase> <phrase role="special">&lt;</phrase><phrase role="keyword">class</phrase> <phrase role="identifier">T</phrase><phrase role="special">&gt;</phrase>
6646 <phrase role="keyword">struct</phrase> <phrase role="identifier">add_volatile</phrase>
6647 <phrase role="special">{</phrase>
6648    <phrase role="keyword">typedef</phrase> <replaceable>see-below</replaceable> <phrase role="identifier">type</phrase><phrase role="special">;</phrase>
6649 <phrase role="special">};</phrase>
6650 </programlisting>
6651   </section>
6652
6653
6654     <index type="class_name">
6655   <title>Class Index</title>
6656   </index>
6657   <index type="typedef_name">
6658   <title>Typedef Index</title>
6659   </index>
6660   <index type="macro_name">
6661   <title>Macro Index</title>
6662   </index>
6663      <index type="test_index_1">
6664         <title>Index Test 1</title>
6665      </index>
6666      <index type="test_index_2">
6667         <title>Index Test 2</title>
6668      </index>
6669      <index/>
6670
6671 </chapter>