Compare commits

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15 Commits

Author SHA1 Message Date
6032348b4c Branch for working on the documentation tools documentation.
[SVN r68640]
2011-02-04 21:18:24 +00:00
3279399fe3 Remove BOOST_ENABLE_ASSERT_MSG_HANDLER; use BOOST_ENABLE_ASSERT_HANDLER in its stead
[SVN r68423]
2011-01-24 20:15:36 +00:00
87875cadda Add BOOST_ASSERT_MSG. Add macros to configure output stream.
[SVN r68414]
2011-01-24 15:37:13 +00:00
c58748cfd9 use declval to fix #5098
[SVN r68373]
2011-01-22 22:18:48 +00:00
58bb88d4bd Revert [67111] (addition of boost/detail/iomanip.hpp) and all the commits that depend on it. ([68137], [68140], [68141], [68154], and [68165]).
[SVN r68168]
2011-01-15 08:11:51 +00:00
11d50ecb9f Replacing the use of <iomanip> with <boost/detail/iomanip.hpp> across Boost.
On Linux, GNU's libstdc++, which is the default stdlib for icc and clang,
cannot parse the <iomanip> header in version 4.5+ (which thankfully neither
compiler advises the use of yet), as it's original C++98-friendly
implementation has been replaced with a gnu++0x implementation.
<boost/detail/iomanip.hpp> is a portable implementation of <iomanip>, providing
boost::detail::setfill, boost::detail::setbase, boost::detail::setw,
boost::detail::setprecision, boost::detail::setiosflags and
boost::detail::resetiosflags. 



[SVN r68140]
2011-01-14 02:35:58 +00:00
636283d7c2 Limit warning suppression to old versions of VC++, fixes #4432
[SVN r67278]
2010-12-16 17:30:46 +00:00
1df0bf80bc Stop inspect complaining that assert is used in BOOST_ASSERT.
[SVN r66574]
2010-11-14 18:37:37 +00:00
71e78a0081 Add declval and common type from Vicente J. Botet Escriba.
Regenerate docs.

[SVN r65443]
2010-09-17 12:12:03 +00:00
f7e4b0e399 Make sure that utility/index.html has a complete list of components. Fixes #4629.
[SVN r65437]
2010-09-16 15:40:47 +00:00
fb1d2effef correction to result_of documentation
[SVN r64696]
2010-08-09 16:23:50 +00:00
94b91e8c92 updated result_of documentation
[SVN r64695]
2010-08-09 16:07:20 +00:00
a4b8043e68 Fix some header links.
[SVN r64006]
2010-07-14 08:15:33 +00:00
b4a08fc80e Added test for private_int_array_pair, hoping to (possibly) fix a minion-clang/darwin-4.2.1 failure at boost.org/development/tests/trunk/developer/utility_.html
[SVN r63045]
2010-06-17 16:53:55 +00:00
9da96d9737 Added value_init_workaround_test, reviewed by Fernando Cacciola, see #3869
[SVN r63014]
2010-06-16 08:45:43 +00:00
21 changed files with 841 additions and 55 deletions

View File

@ -17,36 +17,89 @@
<td colspan="2" height="64">&nbsp;</td>
</tr>
</table>
<p>
<a href="#BOOST_ASSERT">BOOST_ASSERT</a><br>
<a href="#BOOST_ASSERT_MSG">BOOST_ASSERT_MSG</a><br>
<a href="#BOOST_VERIFY">BOOST_VERIFY</a></p>
<h2><a name="BOOST_ASSERT">BOOST_ASSERT</a></h2>
<p>
The header <STRONG>&lt;boost/assert.hpp&gt;</STRONG> defines the macro <b>BOOST_ASSERT</b>,
which is similar to the standard <STRONG>assert</STRONG> macro defined in <STRONG>&lt;cassert&gt;</STRONG>.
The macro is intended to be used in Boost libraries.
The macro is intended to be used in both Boost libraries and user
code.
</p>
<P>By default, <tt>BOOST_ASSERT(expr)</tt> is equivalent to <tt>assert(expr)</tt>.</P>
<P>When the macro <STRONG>BOOST_DISABLE_ASSERTS</STRONG> is defined when <STRONG>&lt;boost/assert.hpp&gt;</STRONG>
<P>If the macro <STRONG>BOOST_DISABLE_ASSERTS</STRONG> is defined when <STRONG>&lt;boost/assert.hpp&gt;</STRONG>
is included, <tt>BOOST_ASSERT(expr)</tt> is defined as <tt>((void)0)</tt>. This
allows users to selectively disable <STRONG>BOOST_ASSERT</STRONG> without
affecting the definition of the standard <STRONG>assert</STRONG>.</P>
<P>When the macro <STRONG>BOOST_ENABLE_ASSERT_HANDLER</STRONG> is defined when <STRONG>&lt;boost/assert.hpp&gt;</STRONG>
<P>If the macro <STRONG>BOOST_ENABLE_ASSERT_HANDLER</STRONG> is defined when <STRONG>&lt;boost/assert.hpp&gt;</STRONG>
is included, <tt>BOOST_ASSERT(expr)</tt> evaluates <b>expr</b> and, if the
result is false, evaluates the expression</P>
<blockquote>
<P><tt>::boost::assertion_failed(#expr, <a href="current_function.html">BOOST_CURRENT_FUNCTION</a>,
__FILE__, __LINE__)</tt></P>
</blockquote>
<P><STRONG>assertion_failed</STRONG> is declared in <STRONG>&lt;boost/assert.hpp&gt;</STRONG>
as</P>
<pre>
namespace boost
<blockquote>
<pre>namespace boost
{
void assertion_failed(char const * expr, char const * function, char const * file, long line);
void assertion_failed(char const * expr, char const * function, char const * file, long line);
}
</pre>
</blockquote>
<p>but it is never defined. The user is expected to supply an appropriate
definition.</p>
<P>As is the case with <STRONG>&lt;cassert&gt;</STRONG>, <STRONG>&lt;boost/assert.hpp&gt;</STRONG>
can be included multiple times in a single translation unit. <STRONG>BOOST_ASSERT</STRONG>
will be redefined each time as specified above.</P>
<h2><a name="BOOST_ASSERT_MSG">BOOST_ASSERT_MSG</a></h2>
<p>
The header <STRONG>&lt;boost/assert.hpp&gt;</STRONG> defines the macro <b>BOOST_ASSERT_MSG</b>,
which is similar to the standard <STRONG>assert</STRONG> macro defined in <STRONG>&lt;cassert&gt;</STRONG>,
but with an additional macro parameter supplying an error message. The macro is intended to be used in both Boost libraries
and user code.
</p>
<P> <tt>BOOST_ASSERT_MSG(expr, msg)</tt> is equivalent to <code>
((void)0)</code> if <b>BOOST_DISABLE_ASSERTS</b> or <b>NDEBUG</b> are
defined or <code>expr</code> evaluates to <code>true</code>. If those
macros and <STRONG>BOOST_ENABLE_ASSERT_HANDLER</STRONG> are not
defined, and <code>expr</code> evaluates to <code>false</code>, an error
message that includes <tt>#expr</tt>, <tt>msg</tt>, <tt> <a href="current_function.html">BOOST_CURRENT_FUNCTION</a></tt>, <tt>
__FILE__</tt>, and <tt>__LINE__</tt> is sent to output stream <b>
BOOST_ASSERT_MSG_OSTREAM</b>
and <code>std::abort()</code> is called.</P>
<P> <b>BOOST_ASSERT_MSG_OSTREAM</b> defines the output stream. It defaults to <code>std::cerr</code>.
Integrated development environments (IDE's) like Microsoft Visual Studio
may produce easier to understand output if messages go to a different
stream, such as <code>std::cout</code>. Users may define <b>BOOST_ASSERT_MSG_OSTREAM</b> before including <STRONG>&lt;boost/assert.hpp&gt;</STRONG>
to specify a different output stream.&nbsp; </P>
<P>If the macro <STRONG>BOOST_ENABLE_ASSERT_HANDLER</STRONG> is defined when <STRONG>&lt;boost/assert.hpp&gt;</STRONG>
is included, instead of sending a error message to an output
stream, this expression is evaluated</P>
<blockquote>
<P><tt>::boost::assertion_failed_msg(#expr, msg, <a href="current_function.html">BOOST_CURRENT_FUNCTION</a>,
__FILE__, __LINE__)</tt></P>
</blockquote>
<P><STRONG>assertion_failed_msg</STRONG> is declared in <STRONG>&lt;boost/assert.hpp&gt;</STRONG>
as</P>
<blockquote>
<pre>namespace boost
{
void assertion_failed_msg(char const * expr, char const * msg, char const * function, char const * file, long line);
}
</pre>
</blockquote>
<p>but it is never defined. The user is expected to supply an appropriate
definition.</p>
<P>As is the case with <STRONG>&lt;cassert&gt;</STRONG>, <STRONG>&lt;boost/assert.hpp&gt;</STRONG>
can be included multiple times in a single translation unit. <STRONG>BOOST_ASSERT_MSG</STRONG>
will be redefined each time as specified above.</P>
<h2><a name="BOOST_VERIFY">BOOST_VERIFY</a></h2>
<p><STRONG>&lt;boost/assert.hpp&gt;</STRONG> also defines the macro <STRONG>BOOST_VERIFY</STRONG>.
It has exactly the same behavior as <STRONG>BOOST_ASSERT</STRONG>, except that
the expression that is passed to <STRONG>BOOST_VERIFY</STRONG> is always
@ -54,8 +107,9 @@ void assertion_failed(char const * expr, char const * function, char const * fil
effects; it can also help suppress warnings about unused variables when the
only use of the variable is inside an assertion.</p>
<p><br>
<small>Copyright <20> 2002, 2007 by Peter Dimov. Distributed under the Boost Software
<small>Copyright <20> 2002, 2007 by Peter Dimov.&nbsp; Copyright <20> 2011
by Beman Dawes. Distributed under the Boost Software
License, Version 1.0. See accompanying file <A href="../../LICENSE_1_0.txt">LICENSE_1_0.txt</A>
or copy at <A href="http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</A>.</small></p>
</body>
</html>
</html>

View File

@ -2,6 +2,7 @@
// assert_test.cpp - a test for boost/assert.hpp
//
// Copyright (c) 2002 Peter Dimov and Multi Media Ltd.
// Copyright (2) Beman Dawes 2011
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
@ -20,6 +21,11 @@ void test_default()
BOOST_ASSERT(x);
BOOST_ASSERT(x == 1);
BOOST_ASSERT(&x);
BOOST_ASSERT_MSG(1, "msg");
BOOST_ASSERT_MSG(x, "msg");
BOOST_ASSERT_MSG(x == 1, "msg");
BOOST_ASSERT_MSG(&x, "msg");
}
#define BOOST_DISABLE_ASSERTS
@ -34,13 +40,23 @@ void test_disabled()
BOOST_ASSERT(x == 1);
BOOST_ASSERT(&x);
BOOST_ASSERT_MSG(1, "msg");
BOOST_ASSERT_MSG(x, "msg");
BOOST_ASSERT_MSG(x == 1, "msg");
BOOST_ASSERT_MSG(&x, "msg");
BOOST_ASSERT(0);
BOOST_ASSERT(!x);
BOOST_ASSERT(x == 0);
BOOST_ASSERT_MSG(0, "msg");
BOOST_ASSERT_MSG(!x, "msg");
BOOST_ASSERT_MSG(x == 0, "msg");
void * p = 0;
BOOST_ASSERT(p);
BOOST_ASSERT_MSG(p, "msg");
// supress warnings
p = &x;
@ -55,6 +71,7 @@ void test_disabled()
#include <cstdio>
int handler_invoked = 0;
int msg_handler_invoked = 0;
void boost::assertion_failed(char const * expr, char const * function, char const * file, long line)
{
@ -66,11 +83,24 @@ void boost::assertion_failed(char const * expr, char const * function, char cons
++handler_invoked;
}
void boost::assertion_failed_msg(char const * expr, char const * msg, char const * function,
char const * file, long line)
{
#if !defined(BOOST_NO_STDC_NAMESPACE)
using std::printf;
#endif
printf("Expression: %s Message: %s\nFunction: %s\nFile: %s\nLine: %ld\n\n",
expr, msg, function, file, line);
++msg_handler_invoked;
}
struct X
{
static void f()
{
BOOST_ASSERT(0);
BOOST_ASSERT_MSG(0, "msg f()");
}
};
@ -83,21 +113,35 @@ void test_handler()
BOOST_ASSERT(x == 1);
BOOST_ASSERT(&x);
BOOST_ASSERT_MSG(1, "msg2");
BOOST_ASSERT_MSG(x, "msg3");
BOOST_ASSERT_MSG(x == 1, "msg4");
BOOST_ASSERT_MSG(&x, "msg5");
BOOST_ASSERT(0);
BOOST_ASSERT(!x);
BOOST_ASSERT(x == 0);
BOOST_ASSERT_MSG(0,"msg 0");
BOOST_ASSERT_MSG(!x, "msg !x");
BOOST_ASSERT_MSG(x == 0, "msg x == 0");
void * p = 0;
BOOST_ASSERT(p);
BOOST_ASSERT_MSG(p, "msg p");
X::f();
BOOST_ASSERT(handler_invoked == 5);
BOOST_TEST(handler_invoked == 5);
BOOST_ASSERT_MSG(msg_handler_invoked == 5, "msg_handler_invoked count is wrong");
BOOST_TEST(msg_handler_invoked == 5);
}
#undef BOOST_ENABLE_ASSERT_HANDLER
#undef BOOST_ENABLE_ASSERT_MSG_HANDLER
int main()
{

68
doc/Jamfile.v2 Normal file
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@ -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
;

104
doc/declval.qbk Normal file
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@ -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]

163
doc/html/declval.html Normal file
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@ -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">
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<table cellpadding="2" width="100%"><tr>
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<td align="center"><a href="../../../../index.html">Home</a></td>
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<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
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<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>

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@ -1,8 +1,11 @@
//
// boost/assert.hpp - BOOST_ASSERT(expr)
// BOOST_ASSERT_MSG(expr, msg)
// BOOST_VERIFY(expr)
//
// Copyright (c) 2001, 2002 Peter Dimov and Multi Media Ltd.
// Copyright (c) 2007 Peter Dimov
// Copyright (c) Beman Dawes 2011
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
@ -13,6 +16,16 @@
// See http://www.boost.org/libs/utility/assert.html for documentation.
//
//
// Stop inspect complaining about use of 'assert':
//
// boostinspect:naassert_macro
//
//--------------------------------------------------------------------------------------//
// BOOST_ASSERT //
//--------------------------------------------------------------------------------------//
#undef BOOST_ASSERT
#if defined(BOOST_DISABLE_ASSERTS)
@ -25,18 +38,86 @@
namespace boost
{
void assertion_failed(char const * expr, char const * function, char const * file, long line); // user defined
void assertion_failed(char const * expr,
char const * function, char const * file, long line); // user defined
} // namespace boost
#define BOOST_ASSERT(expr) ((expr)? ((void)0): ::boost::assertion_failed(#expr, BOOST_CURRENT_FUNCTION, __FILE__, __LINE__))
#define BOOST_ASSERT(expr) ((expr) \
? ((void)0) \
: ::boost::assertion_failed(#expr, BOOST_CURRENT_FUNCTION, __FILE__, __LINE__))
#else
# include <assert.h> // .h to support old libraries w/o <cassert> - effect is the same
# define BOOST_ASSERT(expr) assert(expr)
#endif
//--------------------------------------------------------------------------------------//
// BOOST_ASSERT_MSG //
//--------------------------------------------------------------------------------------//
# undef BOOST_ASSERT_MSG
#if defined(BOOST_DISABLE_ASSERTS) || defined(NDEBUG)
#define BOOST_ASSERT_MSG(expr, msg) ((void)0)
#elif defined(BOOST_ENABLE_ASSERT_HANDLER)
#include <boost/current_function.hpp>
namespace boost
{
void assertion_failed_msg(char const * expr, char const * msg,
char const * function, char const * file, long line); // user defined
} // namespace boost
#define BOOST_ASSERT_MSG(expr, msg) ((expr) \
? ((void)0) \
: ::boost::assertion_failed_msg(#expr, msg, BOOST_CURRENT_FUNCTION, __FILE__, __LINE__))
#else
#ifndef BOOST_ASSERT_HPP
#define BOOST_ASSERT_HPP
#include <cstdlib>
#include <iostream>
#include <boost/current_function.hpp>
// IDE's like Visual Studio perform better if output goes to std::cout or
// some other stream, so allow user to configure output stream:
#ifndef BOOST_ASSERT_MSG_OSTREAM
# define BOOST_ASSERT_MSG_OSTREAM std::cerr
#endif
namespace boost
{
namespace assertion
{
namespace detail
{
inline void assertion_failed_msg(char const * expr, char const * msg, char const * function,
char const * file, long line)
{
BOOST_ASSERT_MSG_OSTREAM
<< "***** Internal Program Error - assertion (" << expr << ") failed in "
<< function << ":\n"
<< file << '(' << line << "): " << msg << std::endl;
std::abort();
}
} // detail
} // assertion
} // detail
#endif
#define BOOST_ASSERT_MSG(expr, msg) ((expr) \
? ((void)0) \
: ::boost::assertion::detail::assertion_failed_msg(#expr, msg, \
BOOST_CURRENT_FUNCTION, __FILE__, __LINE__))
#endif
//--------------------------------------------------------------------------------------//
// BOOST_VERIFY //
//--------------------------------------------------------------------------------------//
#undef BOOST_VERIFY
#if defined(BOOST_DISABLE_ASSERTS) || ( !defined(BOOST_ENABLE_ASSERT_HANDLER) && defined(NDEBUG) )

View File

@ -8,6 +8,8 @@
// See http://www.boost.org/libs/utility/operators.htm for documentation.
// Revision History
// 16 Dec 10 Limit warning suppression for 4284 to older versions of VC++
// (Matthew Bradbury, fixes #4432)
// 07 Aug 08 Added "euclidean" spelling. (Daniel Frey)
// 03 Apr 08 Make sure "convertible to bool" is sufficient
// for T::operator<, etc. (Daniel Frey)
@ -88,7 +90,7 @@
# pragma set woff 1234
#endif
#if defined(BOOST_MSVC)
#if BOOST_WORKAROUND(BOOST_MSVC, < 1600)
# pragma warning( disable : 4284 ) // complaint about return type of
#endif // operator-> not begin a UDT

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@ -4,7 +4,7 @@
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/lib/optional for documentation.
// See http://www.boost.org/libs/optional for documentation.
//
// You are welcome to contact the author at:
// fernando_cacciola@hotmail.com

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@ -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

View File

@ -5,7 +5,7 @@
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/lib/optional for documentation.
// See http://www.boost.org/libs/optional for documentation.
//
// You are welcome to contact the author at:
// fernando_cacciola@hotmail.com

View File

@ -5,7 +5,7 @@
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/lib/optional for documentation.
// See http://www.boost.org/libs/optional for documentation.
//
// You are welcome to contact the author at:
// fernando_cacciola@hotmail.com

View File

@ -35,10 +35,7 @@ struct tr1_result_of<F(BOOST_RESULT_OF_ARGS)>
#if !defined(BOOST_NO_DECLTYPE) && defined(BOOST_RESULT_OF_USE_DECLTYPE)
// As of N2588, C++0x result_of only supports function call
// expressions of the form f(x). This precludes support for member
// function pointers, which are invoked with expressions of the form
// o->*f(x). This implementation supports both.
// Uses declval following N3225 20.7.7.6 when F is not a pointer.
template<typename F BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
struct result_of<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T))>
@ -56,18 +53,15 @@ struct result_of<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T))>
namespace detail {
# define BOOST_RESULT_OF_STATIC_MEMBERS(z, n, _) \
static T ## n t ## n; \
/**/
template<typename F BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
class cpp0x_result_of_impl<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T))>
struct cpp0x_result_of_impl<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T))>
{
static F f;
BOOST_PP_REPEAT(BOOST_PP_ITERATION(), BOOST_RESULT_OF_STATIC_MEMBERS, _)
public:
typedef decltype(f(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),t))) type;
typedef decltype(
boost::declval<F>()(
BOOST_PP_ENUM_BINARY_PARAMS(BOOST_PP_ITERATION(), declval<T, >() BOOST_PP_INTERCEPT)
)
) type;
};
} // namespace detail

View File

@ -5,7 +5,7 @@
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/lib/optional for documentation.
// See http://www.boost.org/libs/optional for documentation.
//
// You are welcome to contact the author at:
// fernando_cacciola@hotmail.com

View File

@ -13,7 +13,9 @@
#include <boost/preprocessor/iteration/iterate.hpp>
#include <boost/preprocessor/punctuation/comma_if.hpp>
#include <boost/preprocessor/repetition/enum_params.hpp>
#include <boost/preprocessor/repetition/enum_binary_params.hpp>
#include <boost/preprocessor/repetition/enum_shifted_params.hpp>
#include <boost/preprocessor/facilities/intercept.hpp>
#include <boost/detail/workaround.hpp>
#include <boost/mpl/has_xxx.hpp>
#include <boost/mpl/if.hpp>
@ -22,6 +24,7 @@
#include <boost/type_traits/is_pointer.hpp>
#include <boost/type_traits/is_member_function_pointer.hpp>
#include <boost/type_traits/remove_cv.hpp>
#include <boost/utility/declval.hpp>
#ifndef BOOST_RESULT_OF_NUM_ARGS
# define BOOST_RESULT_OF_NUM_ARGS 10

View File

@ -5,7 +5,7 @@
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/lib/optional for documentation.
// See http://www.boost.org/libs/optional for documentation.
//
// You are welcome to contact the author at:
// fernando_cacciola@hotmail.com

View File

@ -14,20 +14,28 @@
<p>But that doesn't mean there isn't useful stuff here. Take a look:</p>
<blockquote>
<p>
<a href="utility.htm#addressof">addressof</a><br>
<a href="assert.html">assert</a><br>
<a href="base_from_member.html">base_from_member</a><br>
<a href="utility.htm#BOOST_BINARY">BOOST_BINARY</a><br>
<a href="call_traits.htm">call_traits</a><br>
<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="enable_if.html">enable_if</a><br>
<a href="doc/html/declval.html">declval</a><br>
<a href="enable_if.html">enable_if</a><br>
<a href="in_place_factories.html">in_place_factory</a><br>
<a href="iterator_adaptors.htm">iterator_adaptors</a><br>
<a href="generator_iterator.htm">generator iterator adaptors</a><br>
<a href="utility.htm#functions_next_prior">next/prior</a><br>
<a href="utility.htm#Class_noncopyable">noncopyable</a><br>
<a href="operators.htm">operators</a><br>
<a href="utility.htm#result_of">result_of</a><br>
<a href="swap.html">swap</a><br>
<a href="throw_exception.html">throw_exception</a><br>
<a href="utility.htm">utility</a><br>
<a href="value_init.htm">value_init</a></p>
<a href="value_init.htm">value_init</a>
</p>
</blockquote>
<hr>
<p>&copy; Copyright Beman Dawes, 2001</p>

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@ -32,6 +32,7 @@ test-suite utility
[ compile result_of_test.cpp ]
[ run ../shared_iterator_test.cpp ]
[ run ../value_init_test.cpp ]
[ run ../value_init_workaround_test.cpp ]
[ run ../initialized_test.cpp ]
[ compile-fail ../value_init_test_fail1.cpp ]
[ compile-fail ../value_init_test_fail2.cpp ]

0
test/next_prior_test.cpp Executable file → Normal file
View File

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@ -98,6 +98,11 @@ struct no_result_type_or_result_of
unsigned int operator()();
unsigned short operator()() volatile;
const unsigned short operator()() const volatile;
#if !defined(BOOST_NO_RVALUE_REFERENCES)
short operator()(int&&);
int operator()(int&);
long operator()(int const&);
#endif
};
template<typename T>
@ -108,6 +113,11 @@ struct no_result_type_or_result_of_template
unsigned int operator()();
unsigned short operator()() volatile;
const unsigned short operator()() const volatile;
#if !defined(BOOST_NO_RVALUE_REFERENCES)
short operator()(int&&);
int operator()(int&);
long operator()(int const&);
#endif
};
struct X {};
@ -232,6 +242,14 @@ int main()
BOOST_STATIC_ASSERT((is_same<result_of<const no_result_type_or_result_of_template<void>(double)>::type, short>::value));
BOOST_STATIC_ASSERT((is_same<result_of<volatile no_result_type_or_result_of_template<void>(void)>::type, unsigned short>::value));
BOOST_STATIC_ASSERT((is_same<result_of<const volatile no_result_type_or_result_of_template<void>(void)>::type, const unsigned short>::value));
#if !defined(BOOST_NO_RVALUE_REFERENCES)
BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of(int&&)>::type, short>::value));
BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of(int&)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of(int const&)>::type, long>::value));
BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of_template<void>(int&&)>::type, short>::value));
BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of_template<void>(int&)>::type, int>::value));
BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of_template<void>(int const&)>::type, long>::value));
#endif
#endif
return 0;

View File

@ -151,37 +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.</p> <p>If your compiler does not support
<code>decltype</code>, then when <code>F</code> is a
class type with a member type <code>result_type</code>,
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>. When <code>F</code>
does not contain <code>result_type</code>,
<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>

View File

@ -0,0 +1,144 @@
// Copyright 2010, Niels Dekker.
//
// 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)
//
// Test program for the boost::value_initialized<T> workaround.
//
// 17 June 2010 (Created) Niels Dekker
// Switch the workaround off, before inluding "value_init.hpp".
#define BOOST_DETAIL_VALUE_INIT_WORKAROUND 0
#include <boost/utility/value_init.hpp>
#include <iostream> // For cout.
#include <cstdlib> // For EXIT_SUCCESS and EXIT_FAILURE.
namespace
{
struct empty_struct
{
};
// A POD aggregate struct derived from an empty struct.
// Similar to struct Foo1 from Microsoft Visual C++ bug report 484295,
// "VC++ does not value-initialize members of derived classes without
// user-declared constructor", reported in 2009 by Sylvester Hesp:
// https://connect.microsoft.com/VisualStudio/feedback/details/484295
struct derived_struct: empty_struct
{
int data;
};
bool is_value_initialized(const derived_struct& arg)
{
return arg.data == 0;
}
class virtual_destructor_holder
{
public:
int i;
virtual ~virtual_destructor_holder()
{
}
};
bool is_value_initialized(const virtual_destructor_holder& arg)
{
return arg.i == 0;
}
// Equivalent to the Stats class from GCC Bug 33916,
// "Default constructor fails to initialize array members", reported in 2007 by
// Michael Elizabeth Chastain: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33916
// and fixed for GCC 4.2.4.
class private_int_array_pair
{
friend bool is_value_initialized(const private_int_array_pair& arg);
private:
int first[12];
int second[12];
};
bool is_value_initialized(const private_int_array_pair& arg)
{
for ( unsigned i = 0; i < 12; ++i)
{
if ( (arg.first[i] != 0) || (arg.second[i] != 0) )
{
return false;
}
}
return true;
}
template <typename T>
bool is_value_initialized(const T(& arg)[2])
{
return
is_value_initialized(arg[0]) &&
is_value_initialized(arg[1]);
}
template <typename T>
bool is_value_initialized(const boost::value_initialized<T>& arg)
{
return is_value_initialized(arg.data());
}
// Returns zero when the specified object is value-initializated, and one otherwise.
// Prints a message to standard output if the value-initialization has failed.
template <class T>
unsigned failed_to_value_initialized(const T& object, const char *const object_name)
{
if ( is_value_initialized(object) )
{
return 0u;
}
else
{
std::cout << "Note: Failed to value-initialize " << object_name << '.' << std::endl;
return 1u;
}
}
// A macro that passed both the name and the value of the specified object to
// the function above here.
#define FAILED_TO_VALUE_INITIALIZE(value) failed_to_value_initialized(value, #value)
// Equivalent to the dirty_stack() function from GCC Bug 33916,
// "Default constructor fails to initialize array members", reported in 2007 by
// Michael Elizabeth Chastain: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33916
void dirty_stack()
{
unsigned char array_on_stack[4096];
for (unsigned i = 0; i < sizeof(array_on_stack); ++i)
{
array_on_stack[i] = 0x11;
}
}
}
int main()
{
dirty_stack();
// TODO More types may be added later.
const unsigned num_failures =
FAILED_TO_VALUE_INITIALIZE(boost::value_initialized<derived_struct>()) +
FAILED_TO_VALUE_INITIALIZE(boost::value_initialized<virtual_destructor_holder[2]>()) +
FAILED_TO_VALUE_INITIALIZE(boost::value_initialized<private_int_array_pair>());
#ifdef BOOST_DETAIL_VALUE_INIT_WORKAROUND_SUGGESTED
// One or more failures are expected.
return num_failures > 0 ? EXIT_SUCCESS : EXIT_FAILURE;
#else
// No failures are expected.
return num_failures == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
#endif
}