Release 1.45.0 beta 1

[SVN r66473]
Merges changes from Trunk: refer to history.qbk for the details.
2025-12-16 02:18:42 +01:00 · 2010-11-09 18:22:33 +00:00 · 2010-10-01 11:11:16 +00:00 · 2010-09-17 12:12:03 +00:00 · 2010-09-16 15:40:47 +00:00 · 2010-08-11 18:15:46 +00:00
6 changed files with 458 additions and 17 deletions
--- a/doc/Jamfile.v2
+++ b/doc/Jamfile.v2
@@ -0,0 +1,68 @@
+
+# Copyright John Maddock 2005. Use, modification, and distribution are
+# subject to the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+project : requirements
+        # Path for links to Boost:
+        <xsl:param>boost.root=../../../..
+        
+        # Some general style settings:
+        <xsl:param>table.footnote.number.format=1
+        <xsl:param>footnote.number.format=1
+
+        # HTML options first:
+        # Use graphics not text for navigation:
+        <xsl:param>navig.graphics=1
+       # PDF Options:
+        # TOC Generation: this is needed for FOP-0.9 and later:
+        <xsl:param>fop1.extensions=0
+        <xsl:param>xep.extensions=1
+        # TOC generation: this is needed for FOP 0.2, but must not be set to zero for FOP-0.9!
+        <xsl:param>fop.extensions=0
+        # No indent on body text:
+        <xsl:param>body.start.indent=0pt
+        # Margin size:
+        <xsl:param>page.margin.inner=0.5in
+        # Margin size:
+        <xsl:param>page.margin.outer=0.5in
+        # Paper type = A4
+        <xsl:param>paper.type=A4
+        # Yes, we want graphics for admonishments:
+        <xsl:param>admon.graphics=1
+        # Set this one for PDF generation *only*:
+        # default pnd graphics are awful in PDF form,
+        # better use SVG's instead:
+        <format>pdf:<xsl:param>admon.graphics.extension=".svg"
+        <format>pdf:<xsl:param>admon.graphics.path=$(boost-images)/
+        <format>pdf:<xsl:param>boost.url.prefix=http://www.boost.org/doc/libs/release/libs/utility/doc/html
+;
+
+using quickbook ;
+
+path-constant boost-images : ../../../doc/src/images ;
+
+xml declval : declval.qbk ;
+boostbook standalone
+    :
+        declval
+    :
+        # File name of HTML output:
+        <xsl:param>root.filename=declval
+        # How far down we chunk nested sections, basically all of them:
+        <xsl:param>chunk.section.depth=0
+        # Don't put the first section on the same page as the TOC:
+        <xsl:param>chunk.first.sections=0
+        # How far down sections get TOC's
+        <xsl:param>toc.section.depth=1
+        # Max depth in each TOC:
+        <xsl:param>toc.max.depth=1
+        # How far down we go with TOC's
+        <xsl:param>generate.section.toc.level=1
+        
+     ;
+
+
+
+
+
--- a/doc/declval.qbk
+++ b/doc/declval.qbk
@@ -0,0 +1,104 @@
+[/
+ / Copyright (c) 2008 Howard Hinnant
+ / Copyright (c) 2008 Beman Dawes
+ / Copyright (c) 2009-20010 Vicente J. Botet Escriba
+ /
+ / Distributed under the Boost Software License, Version 1.0. (See accompanying
+ / file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+ /]
+
+[article Declval
+    [quickbook 1.5]
+    [authors [Hinnant, Howard]]
+    [authors [Dawes, Beman]]
+    [authors [Botet Escriba, Vicente J.]]
+    [copyright 2008 Howard Hinnant]
+    [copyright 2008 Beman Dawes]
+    [copyright 2009-2010 Vicente J. Botet Escriba]
+    [license
+        Distributed under the Boost Software License, Version 1.0.
+        (See accompanying file LICENSE_1_0.txt or copy at
+        [@http://www.boost.org/LICENSE_1_0.txt])
+    ]
+]
+
+[/===============]
+[section Overview]
+[/===============]
+
+The motivation for `declval` was introduced in [@http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2958.html#Value N2958: 
+Moving Swap Forward]. Here follows a rewording of this chapter.
+
+With the provision of decltype, late-specified return types, and default template-arguments for function templates a 
+new generation of SFINAE patterns will emerge to at least partially compensate the lack of concepts on the C++0x timescale. 
+Using this technique, it is sometimes necessary to obtain an object of a known type in a non-using context, e.g. given the declaration 
+
+  template<class T>
+  T&& declval(); // not used
+  
+as part of the function template declaration 
+
+  template<class To, class From>
+  decltype(static_cast<To>(declval<From>())) convert(From&&);
+  
+or as part of a class template definition 
+
+  template<class> class result_of;
+
+  template<class Fn, class... ArgTypes>
+  struct result_of<Fn(ArgTypes...)> 
+  {
+    typedef decltype(declval<Fn>()(declval<ArgTypes>()...)) type;
+  };
+  
+The role of the function template declval() is a transformation of a type T into a value without using or evaluating this function. 
+The name is supposed to direct the reader's attention to the fact that the expression `declval<T>()` is an lvalue if and only if 
+T is an lvalue-reference, otherwise an rvalue. To extend the domain of this function we can do a bit better by changing its declaration to 
+
+  template<class T>
+  typename std::add_rvalue_reference<T>::type declval(); // not used
+  
+which ensures that we can also use cv void as template parameter. The careful reader might have noticed that `declval()` 
+already exists under the name create() as part of the definition of the semantics of the type trait is_convertible in the C==0x standard. 
+
+The provision of a new library component that allows the production of values in unevaluated expressions is considered as 
+important to realize constrained templates in C++0x where concepts are not available. 
+This extremely light-weight function is expected to be part of the daily tool-box of the C++0x programmer. 
+
+[endsect]
+
+
+[/=================]
+[section:reference Reference ]
+[/=================]
+
+`#include <boost/utility/declval.hpp>`
+
+    namespace boost {
+
+        template <typename T>
+        typename add_rvalue_reference<T>::type declval(); //noexcept; // as unevaluated operand
+
+    }  // namespace boost
+
+
+The library provides the function template declval to simplify the definition of expressions which occur as unevaluated operands.
+
+        template <typename T>
+        typename add_rvalue_reference<T>::type declval();
+
+[*Remarks:] If this function is used, the program is ill-formed.
+
+[*Remarks:] The template parameter T of declval may be an incomplete type.
+
+[*Example:]
+
+    template <class To, class From>
+    decltype(static_cast<To>(declval<From>())) convert(From&&);
+
+Declares a function template convert which only participats in overloading if the type From can be explicitly converted to type To. 
+
+[endsect]
+
+
+
--- a/doc/html/declval.html
+++ b/doc/html/declval.html
@@ -0,0 +1,163 @@
+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
+<title>Declval</title>
+<link rel="stylesheet" href="../../../../doc/src/boostbook.css" type="text/css">
+<meta name="generator" content="DocBook XSL Stylesheets V1.74.0">
+<link rel="home" href="declval.html" title="Declval">
+</head>
+<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
+<table cellpadding="2" width="100%"><tr>
+<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../boost.png"></td>
+<td align="center"><a href="../../../../index.html">Home</a></td>
+<td align="center"><a href="../../../../libs/libraries.htm">Libraries</a></td>
+<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
+<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
+<td align="center"><a href="../../../../more/index.htm">More</a></td>
+</tr></table>
+<hr>
+<div class="spirit-nav"></div>
+<div class="article" lang="en">
+<div class="titlepage">
+<div>
+<div><h2 class="title">
+<a name="declval"></a>Declval</h2></div>
+<div><div class="authorgroup">
+<div class="author"><h3 class="author">
+<span class="firstname">Howard</span> <span class="surname">Hinnant</span>
+</h3></div>
+<div class="author"><h3 class="author">
+<span class="firstname">Beman</span> <span class="surname">Dawes</span>
+</h3></div>
+<div class="author"><h3 class="author">
+<span class="firstname">Vicente J.</span> <span class="surname">Botet Escriba</span>
+</h3></div>
+</div></div>
+<div><p class="copyright">Copyright &#169; 2008 Howard Hinnant</p></div>
+<div><p class="copyright">Copyright &#169; 2008 Beman Dawes</p></div>
+<div><p class="copyright">Copyright &#169; 2009 -2010 Vicente J. Botet Escriba</p></div>
+<div><div class="legalnotice">
+<a name="id879409"></a><p>
+        Distributed under the Boost Software License, Version 1.0. (See accompanying
+        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
+      </p>
+</div></div>
+</div>
+<hr>
+</div>
+<div class="toc">
+<p><b>Table of Contents</b></p>
+<dl>
+<dt><span class="section"><a href="declval.html#declval.overview">Overview</a></span></dt>
+<dt><span class="section"><a href="declval.html#declval.reference"> Reference </a></span></dt>
+</dl>
+</div>
+<div class="section" lang="en">
+<div class="titlepage"><div><div><h2 class="title" style="clear: both">
+<a name="declval.overview"></a><a class="link" href="declval.html#declval.overview" title="Overview">Overview</a>
+</h2></div></div></div>
+<p>
+      The motivation for <code class="computeroutput"><span class="identifier">declval</span></code>
+      was introduced in <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2958.html#Value" target="_top">N2958:
+      Moving Swap Forward</a>. Here follows a rewording of this chapter.
+    </p>
+<p>
+      With the provision of decltype, late-specified return types, and default template-arguments
+      for function templates a new generation of SFINAE patterns will emerge to at
+      least partially compensate the lack of concepts on the C++0x timescale. Using
+      this technique, it is sometimes necessary to obtain an object of a known type
+      in a non-using context, e.g. given the declaration
+    </p>
+<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span>
+<span class="identifier">T</span><span class="special">&amp;&amp;</span> <span class="identifier">declval</span><span class="special">();</span> <span class="comment">// not used
+</span></pre>
+<p>
+      as part of the function template declaration
+    </p>
+<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">To</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">From</span><span class="special">&gt;</span>
+<span class="identifier">decltype</span><span class="special">(</span><span class="keyword">static_cast</span><span class="special">&lt;</span><span class="identifier">To</span><span class="special">&gt;(</span><span class="identifier">declval</span><span class="special">&lt;</span><span class="identifier">From</span><span class="special">&gt;()))</span> <span class="identifier">convert</span><span class="special">(</span><span class="identifier">From</span><span class="special">&amp;&amp;);</span>
+</pre>
+<p>
+      or as part of a class template definition
+    </p>
+<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span><span class="special">&gt;</span> <span class="keyword">class</span> <span class="identifier">result_of</span><span class="special">;</span>
+
+<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Fn</span><span class="special">,</span> <span class="keyword">class</span><span class="special">...</span> <span class="identifier">ArgTypes</span><span class="special">&gt;</span>
+<span class="keyword">struct</span> <span class="identifier">result_of</span><span class="special">&lt;</span><span class="identifier">Fn</span><span class="special">(</span><span class="identifier">ArgTypes</span><span class="special">...)&gt;</span> 
+<span class="special">{</span>
+  <span class="keyword">typedef</span> <span class="identifier">decltype</span><span class="special">(</span><span class="identifier">declval</span><span class="special">&lt;</span><span class="identifier">Fn</span><span class="special">&gt;()(</span><span class="identifier">declval</span><span class="special">&lt;</span><span class="identifier">ArgTypes</span><span class="special">&gt;()...))</span> <span class="identifier">type</span><span class="special">;</span>
+<span class="special">};</span>
+</pre>
+<p>
+      The role of the function template declval() is a transformation of a type T
+      into a value without using or evaluating this function. The name is supposed
+      to direct the reader's attention to the fact that the expression <code class="computeroutput"><span class="identifier">declval</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;()</span></code> is
+      an lvalue if and only if T is an lvalue-reference, otherwise an rvalue. To
+      extend the domain of this function we can do a bit better by changing its declaration
+      to
+    </p>
+<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span>
+<span class="keyword">typename</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">add_rvalue_reference</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">type</span> <span class="identifier">declval</span><span class="special">();</span> <span class="comment">// not used
+</span></pre>
+<p>
+      which ensures that we can also use cv void as template parameter. The careful
+      reader might have noticed that <code class="computeroutput"><span class="identifier">declval</span><span class="special">()</span></code> already exists under the name create() as
+      part of the definition of the semantics of the type trait is_convertible in
+      the C==0x standard.
+    </p>
+<p>
+      The provision of a new library component that allows the production of values
+      in unevaluated expressions is considered as important to realize constrained
+      templates in C++0x where concepts are not available. This extremely light-weight
+      function is expected to be part of the daily tool-box of the C++0x programmer.
+    </p>
+</div>
+<div class="section" lang="en">
+<div class="titlepage"><div><div><h2 class="title" style="clear: both">
+<a name="declval.reference"></a><a class="link" href="declval.html#declval.reference" title="Reference"> Reference </a>
+</h2></div></div></div>
+<p>
+      <code class="computeroutput"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">utility</span><span class="special">/</span><span class="identifier">declval</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>
+    </p>
+<pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">boost</span> <span class="special">{</span>
+
+    <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">&gt;</span>
+    <span class="keyword">typename</span> <span class="identifier">add_rvalue_reference</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">type</span> <span class="identifier">declval</span><span class="special">();</span> <span class="comment">//noexcept; // as unevaluated operand
+</span>
+<span class="special">}</span>  <span class="comment">// namespace boost
+</span></pre>
+<p>
+      The library provides the function template declval to simplify the definition
+      of expressions which occur as unevaluated operands.
+    </p>
+<pre class="programlisting"><span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">&gt;</span>
+<span class="keyword">typename</span> <span class="identifier">add_rvalue_reference</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">type</span> <span class="identifier">declval</span><span class="special">();</span>
+</pre>
+<p>
+      <span class="bold"><strong>Remarks:</strong></span> If this function is used, the program
+      is ill-formed.
+    </p>
+<p>
+      <span class="bold"><strong>Remarks:</strong></span> The template parameter T of declval
+      may be an incomplete type.
+    </p>
+<p>
+      <span class="bold"><strong>Example:</strong></span>
+    </p>
+<pre class="programlisting"><span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">To</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">From</span><span class="special">&gt;</span>
+<span class="identifier">decltype</span><span class="special">(</span><span class="keyword">static_cast</span><span class="special">&lt;</span><span class="identifier">To</span><span class="special">&gt;(</span><span class="identifier">declval</span><span class="special">&lt;</span><span class="identifier">From</span><span class="special">&gt;()))</span> <span class="identifier">convert</span><span class="special">(</span><span class="identifier">From</span><span class="special">&amp;&amp;);</span>
+</pre>
+<p>
+      Declares a function template convert which only participats in overloading
+      if the type From can be explicitly converted to type To.
+    </p>
+</div>
+</div>
+<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
+<td align="left"><p><small>Last revised: September 16, 2010 at 16:19:10 GMT</small></p></td>
+<td align="right"><div class="copyright-footer"></div></td>
+</tr></table>
+<hr>
+<div class="spirit-nav"></div>
+</body>
+</html>
--- a/include/boost/utility/declval.hpp
+++ b/include/boost/utility/declval.hpp
@@ -0,0 +1,44 @@
+//  common_type.hpp  ---------------------------------------------------------//
+
+//  Copyright 2010 Vicente J. Botet Escriba
+
+//  Distributed under the Boost Software License, Version 1.0.
+//  See http://www.boost.org/LICENSE_1_0.txt
+
+#ifndef BOOST_TYPE_TRAITS_EXT_DECLVAL__HPP
+#define BOOST_TYPE_TRAITS_EXT_DECLVAL__HPP
+
+#include <boost/config.hpp>
+
+//----------------------------------------------------------------------------//
+
+#include <boost/type_traits/add_rvalue_reference.hpp>
+
+//----------------------------------------------------------------------------//
+//                                                                            //
+//                           C++03 implementation of                          //
+//                          Written by Vicente J. Botet Escriba               //
+//~ 20.3.4 Function template declval [declval]
+//~ 1 The library provides the function template declval to simplify the definition of expressions which occur as
+//~ unevaluated operands.
+//~ 2 Remarks: If this function is used, the program is ill-formed.
+//~ 3 Remarks: The template parameter T of declval may be an incomplete type.
+//~ [ Example:
+
+//~ template <class To, class From>
+//~ decltype(static_cast<To>(declval<From>())) convert(From&&);
+
+//~ declares a function template convert which only participats in overloading if the type From can be
+//~ explicitly converted to type To. For another example see class template common_type (20.7.6.6). <20>end
+//~ example ]
+//                                                                            //
+//----------------------------------------------------------------------------//
+
+namespace boost {
+
+    template <typename T>
+    typename add_rvalue_reference<T>::type declval(); //noexcept; // as unevaluated operand
+
+}  // namespace boost
+
+#endif  // BOOST_TYPE_TRAITS_EXT_DECLVAL__HPP
--- a/index.html
+++ b/index.html
@@ -20,6 +20,7 @@
 				<a href="checked_delete.html">checked_delete</a><br>
 				<a href="compressed_pair.htm">compressed_pair</a><br>
 				<a href="current_function.html">current_function</a><br>
+				<a href="doc/html/declval.html">declval</a><br>
 				<a href="enable_if.html">enable_if</a><br>
            <a href="iterator_adaptors.htm">iterator_adaptors</a><br>
            <a href="generator_iterator.htm">generator iterator adaptors</a><br>
@@ -40,3 +41,4 @@
 			<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->07 November, 2006<!--webbot bot="Timestamp" endspan i-checksum="39368" --></p>
 		</body>
 </html>
+
--- a/utility.htm
+++ b/utility.htm
@@ -151,35 +151,95 @@ void f() {
                <code>result_of&lt;F(T1, T2, ...,
                T<em>N</em>)&gt;::type</code> defines the result type
                of the expression <code>f(t1, t2,
-                ...,t<em>N</em>)</code>. The implementation permits
+                ...,t<em>N</em>)</code>. This implementation permits
                the type <code>F</code> to be a function pointer,
                function reference, member function pointer, or class
-                type. When <code>F</code> is a class type with a
+                type. By default, <em>N</em> may be any value between 0 and
+                10. To change the upper limit, define the macro
+                <code>BOOST_RESULT_OF_NUM_ARGS</code> to the maximum
+                value for <em>N</em>. Class template <code>result_of</code>
+                resides in the header <code>&lt;<a
+                href="../../boost/utility/result_of.hpp">boost/utility/result_of.hpp</a>&gt;</code>.</p>
+
+                <p>If your compiler supports <code>decltype</code>,
+                then you can enable automatic result type deduction by
+                defining the macro <code>BOOST_RESULT_OF_USE_DECLTYPE</code>,
+                as in the following example.</p>
+
+                <blockquote>
+                <pre>#define BOOST_RESULT_OF_USE_DECLTYPE
+#include &lt;boost/utility/result_of.hpp&gt;
+
+struct functor {
+    template&lt;class T&gt;
+    T operator()(T x)
+    {
+        return x;
+    }
+};
+
+typedef boost::result_of&lt;
+    functor(int)
+&gt;::type type;</pre>
+                </blockquote>
+
+                <p>If <code>decltype</code> is not enabled,
+                then automatic result type deduction of function
+                objects is not possible. Instead, <code>result_of</code>
+                uses the following protocol to allow the programmer to
+                specify a type. When <code>F</code> is a class type with a
                member type <code>result_type</code>,
                <code>result_of&lt;F(T1, T2, ...,
                T<em>N</em>)&gt;</code> is
-                <code>F::result_type</code>. Otherwise,
+                <code>F::result_type</code>. When <code>F</code> does
+                not contain <code>result_type</code>,
                <code>result_of&lt;F(T1, T2, ...,
                T<em>N</em>)&gt;</code> is <code>F::result&lt;F(T1,
                T2, ..., T<em>N</em>)&gt;::type</code> when
                <code><em>N</em> &gt; 0</code> or <code>void</code>
-                when <code><em>N</em> = 0</code>. For additional
-                information about <code>result_of</code>, see the
-                C++ Library Technical Report, <a
-                href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1836.pdf">N1836</a>,
-                or, for motivation and design rationale, the <code>result_of</code> <a
-                href="http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/papers/2003/n1454.html">proposal</a>.</p>
+                when <code><em>N</em> = 0</code>. Note that it is the
+                responsibility of the programmer to ensure that
+                function objects accurately advertise their result
+                type via this protocol, as in the following
+                example.</p>

-                <p>Class template <code>result_of</code> resides in
-                the header <code>&lt;<a
-                href="../../boost/utility/result_of.hpp">boost/utility/result_of.hpp</a>&gt;</code>. By
-                default, <em>N</em> may be any value between 0 and
-                10. To change the upper limit, define the macro
-                <code>BOOST_RESULT_OF_NUM_ARGS</code> to the maximum
-                value for <em>N</em>.</p>
+                <blockquote>
+                <pre>struct functor {
+    template&lt;class&gt; struct result;
+
+    template&lt;class F, class T&gt;
+    struct result&lt;F(T)&gt; {
+        typedef T type;
+    };
+
+    template&lt;class T&gt;
+    T operator()(T x)
+    {
+        return x;
+    }
+};
+
+typedef boost::result_of&lt;
+    functor(int)
+&gt;::type type;</pre>
+                </blockquote>

                <a name="BOOST_NO_RESULT_OF"></a>
-                <p>This implementation of <code>result_of</code> requires class template partial specialization, the ability to parse function types properly, and support for SFINAE. If <code>result_of</code> is not supported by your compiler, including the header <code>boost/utility/result_of.hpp</code> will define the macro <code>BOOST_NO_RESULT_OF</code>. Contributed by Doug Gregor.</p>
+                <p>This implementation of <code>result_of</code>
+                requires class template partial specialization, the
+                ability to parse function types properly, and support
+                for SFINAE. If <code>result_of</code> is not supported
+                by your compiler, including the header 
+                <code>boost/utility/result_of.hpp</code> will
+                define the macro <code>BOOST_NO_RESULT_OF</code>.</p>
+
+                <p>For additional information
+                about <code>result_of</code>, see the C++ Library
+                Technical Report,
+                <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1836.pdf">N1836</a>,
+                or, for motivation and design rationale,
+                the <code>result_of</code> <a href="http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/papers/2003/n1454.html">proposal</a>.</p>
+                Contributed by Doug Gregor.</p>

 		<h2>Class templates for the Base-from-Member Idiom</h2>
 		<p>See <a href="base_from_member.html">separate documentation</a>.</p>