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boost-1.50
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| Author | SHA1 | Date | |
|---|---|---|---|
|
6032348b4c |
@@ -1,6 +1,7 @@
|
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[/
|
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/ Copyright (c) 2008 Howard Hinnant
|
||||
/ Copyright (c) 2009-20012 Vicente J. Botet Escriba
|
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/ Copyright (c) 2008 Beman Dawes
|
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/ Copyright (c) 2009-20010 Vicente J. Botet Escriba
|
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/
|
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/ Distributed under the Boost Software License, Version 1.0. (See accompanying
|
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/ file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
|
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@@ -9,9 +10,11 @@
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[article Declval
|
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[quickbook 1.5]
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[authors [Hinnant, Howard]]
|
||||
[authors [Dawes, Beman]]
|
||||
[authors [Botet Escriba, Vicente J.]]
|
||||
[copyright 2008 Howard Hinnant]
|
||||
[copyright 2009-2012 Vicente J. Botet Escriba]
|
||||
[copyright 2008 Beman Dawes]
|
||||
[copyright 2009-2010 Vicente J. Botet Escriba]
|
||||
[license
|
||||
Distributed under the Boost Software License, Version 1.0.
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(See accompanying file LICENSE_1_0.txt or copy at
|
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@@ -56,9 +59,9 @@ T is an lvalue-reference, otherwise an rvalue. To extend the domain of this func
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typename std::add_rvalue_reference<T>::type declval(); // not used
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|
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which ensures that we can also use cv void as template parameter. The careful reader might have noticed that `declval()`
|
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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.
|
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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
|
||||
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.
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|
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@@ -74,7 +77,7 @@ This extremely light-weight function is expected to be part of the daily tool-bo
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namespace boost {
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template <typename T>
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typename add_rvalue_reference<T>::type declval() noexcept; // as unevaluated operand
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typename add_rvalue_reference<T>::type declval(); //noexcept; // as unevaluated operand
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} // namespace boost
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@@ -93,23 +96,9 @@ The library provides the function template declval to simplify the definition of
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template <class To, class From>
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decltype(static_cast<To>(declval<From>())) convert(From&&);
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|
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Declares a function template convert which only participates in overloading if the type From can be explicitly converted to type To.
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[endsect]
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[/===============]
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[section History]
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[/===============]
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[heading boost 1.50]
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|
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Fixes:
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|
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* [@http://svn.boost.org/trac/boost/ticket/6570 #6570] Adding noexcept to boost::declval.
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|
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Declares a function template convert which only participats in overloading if the type From can be explicitly converted to type To.
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[endsect]
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|
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|
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|
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@@ -3,7 +3,7 @@
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<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
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<title>Declval</title>
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<link rel="stylesheet" href="../../../../doc/src/boostbook.css" type="text/css">
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<meta name="generator" content="DocBook XSL Stylesheets V1.76.0">
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<meta name="generator" content="DocBook XSL Stylesheets V1.74.0">
|
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<link rel="home" href="declval.html" title="Declval">
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</head>
|
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<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
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@@ -17,7 +17,7 @@
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</tr></table>
|
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<hr>
|
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<div class="spirit-nav"></div>
|
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<div class="article">
|
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<div class="article" lang="en">
|
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<div class="titlepage">
|
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<div>
|
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<div><h2 class="title">
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@@ -27,13 +27,17 @@
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<span class="firstname">Howard</span> <span class="surname">Hinnant</span>
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</h3></div>
|
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<div class="author"><h3 class="author">
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<span class="firstname">Beman</span> <span class="surname">Dawes</span>
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</h3></div>
|
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<div class="author"><h3 class="author">
|
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<span class="firstname">Vicente J.</span> <span class="surname">Botet Escriba</span>
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</h3></div>
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</div></div>
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<div><p class="copyright">Copyright © 2008 Howard Hinnant</p></div>
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<div><p class="copyright">Copyright © 2009 -2012 Vicente J. Botet Escriba</p></div>
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<div><p class="copyright">Copyright © 2008 Beman Dawes</p></div>
|
||||
<div><p class="copyright">Copyright © 2009 -2010 Vicente J. Botet Escriba</p></div>
|
||||
<div><div class="legalnotice">
|
||||
<a name="idp13449552"></a><p>
|
||||
<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>)
|
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</p>
|
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@@ -45,11 +49,10 @@
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<p><b>Table of Contents</b></p>
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<dl>
|
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<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>
|
||||
<dt><span class="section"><a href="declval.html#declval.history">History</a></span></dt>
|
||||
<dt><span class="section"><a href="declval.html#declval.reference"> Reference </a></span></dt>
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</dl>
|
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</div>
|
||||
<div class="section">
|
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<div class="section" lang="en">
|
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<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>
|
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@@ -100,18 +103,18 @@
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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.
|
||||
the C==0x standard.
|
||||
</p>
|
||||
<p>
|
||||
The provision of a new library component that allows the production of values
|
||||
in unevaluated expressions is considered 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.
|
||||
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">
|
||||
<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>
|
||||
<a name="declval.reference"></a><a class="link" href="declval.html#declval.reference" title="Reference"> Reference </a>
|
||||
</h2></div></div></div>
|
||||
<p>
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||||
<code class="computeroutput"><span class="preprocessor">#include</span> <span class="special"><</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">></span></code>
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@@ -119,7 +122,7 @@
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||||
<pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">boost</span> <span class="special">{</span>
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|
||||
<span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">></span>
|
||||
<span class="keyword">typename</span> <span class="identifier">add_rvalue_reference</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">type</span> <span class="identifier">declval</span><span class="special">()</span> <span class="identifier">noexcept</span><span class="special">;</span> <span class="comment">// as unevaluated operand
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||||
<span class="keyword">typename</span> <span class="identifier">add_rvalue_reference</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">type</span> <span class="identifier">declval</span><span class="special">();</span> <span class="comment">//noexcept; // as unevaluated operand
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||||
</span>
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||||
<span class="special">}</span> <span class="comment">// namespace boost
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||||
</span></pre>
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||||
@@ -145,29 +148,13 @@
|
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<span class="identifier">decltype</span><span class="special">(</span><span class="keyword">static_cast</span><span class="special"><</span><span class="identifier">To</span><span class="special">>(</span><span class="identifier">declval</span><span class="special"><</span><span class="identifier">From</span><span class="special">>()))</span> <span class="identifier">convert</span><span class="special">(</span><span class="identifier">From</span><span class="special">&&);</span>
|
||||
</pre>
|
||||
<p>
|
||||
Declares a function template convert which only participates in overloading
|
||||
Declares a function template convert which only participats in overloading
|
||||
if the type From can be explicitly converted to type To.
|
||||
</p>
|
||||
</div>
|
||||
<div class="section">
|
||||
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
|
||||
<a name="declval.history"></a><a class="link" href="declval.html#declval.history" title="History">History</a>
|
||||
</h2></div></div></div>
|
||||
<a name="declval.history.boost_1_50"></a><h4>
|
||||
<a name="idp13553216"></a>
|
||||
<a class="link" href="declval.html#declval.history.boost_1_50">boost 1.50</a>
|
||||
</h4>
|
||||
<p>
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||||
Fixes:
|
||||
</p>
|
||||
<div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
|
||||
<a href="http://svn.boost.org/trac/boost/ticket/6570" target="_top">#6570</a>
|
||||
Adding noexcept to boost::declval.
|
||||
</li></ul></div>
|
||||
</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: May 28, 2012 at 18:59:06 GMT</small></p></td>
|
||||
<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>
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||||
</tr></table>
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||||
<hr>
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||||
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111
enable_if.html
111
enable_if.html
@@ -21,7 +21,6 @@
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||||
<BR>
|
||||
<BR>
|
||||
Copyright 2003 Jaakko Järvi, Jeremiah Willcock, Andrew Lumsdaine.<BR>
|
||||
Copyright 2011 Matt Calabrese.<BR>
|
||||
<BR>
|
||||
<!--TOC section Introduction-->
|
||||
|
||||
@@ -82,7 +81,7 @@ definitions to find this out. Instantiating the latter definition with
|
||||
<PRE>int::result_type negate(const int&);
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||||
|
||||
</PRE>
|
||||
where the return type is invalid. If this were an error, adding an unrelated function template
|
||||
where the return type is invalid. If this was an error, adding an unrelated function template
|
||||
(that was never called) could break otherwise valid code.
|
||||
Due to the SFINAE principle the above example is not, however, erroneous.
|
||||
The latter definition of <TT>negate</TT> is simply removed from the overload resolution set.<BR>
|
||||
@@ -155,7 +154,6 @@ typename enable_if<boost::is_arithmetic<T>, T>::type
|
||||
foo(T t) { return t; }
|
||||
|
||||
</PRE>
|
||||
|
||||
<!--TOC section Using <TT>enable_if</TT>-->
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<H2><A NAME="htoc5">3</A> Using <TT>enable_if</TT></H2><!--SEC END -->
|
||||
@@ -164,19 +162,8 @@ foo(T t) { return t; }
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The <TT>enable_if</TT> templates are defined in
|
||||
<TT>boost/utility/enable_if.hpp</TT>, which is included by <TT>boost/utility.hpp</TT>.<BR>
|
||||
<BR>
|
||||
With respect to function templates, <TT>enable_if</TT> can be used in multiple different ways:
|
||||
|
||||
<UL>
|
||||
<LI>As the return type of an instantiatied function
|
||||
<LI>As an extra parameter of an instantiated function
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<LI>As an extra template parameter (useful only in a compiler that supports C++0x default
|
||||
arguments for function template parameters, see <A href="#sec:enable_if_0x">Enabling function
|
||||
templates in C++0x</a> for details)
|
||||
</UL>
|
||||
|
||||
In the previous section, the return type form of <TT>enable_if</TT> was shown. As an example
|
||||
of using the form of <TT>enable_if</TT> that works via an extra function parameter, the
|
||||
<TT>foo</TT> function in the previous section could also be written
|
||||
The <TT>enable_if</TT> template can be used either as the return type, or as an
|
||||
extra argument. For example, the <TT>foo</TT> function in the previous section could also be written
|
||||
as:
|
||||
<PRE>template <class T>
|
||||
T foo(T t, typename enable_if<boost::is_arithmetic<T> >::type* dummy = 0);
|
||||
@@ -186,80 +173,18 @@ a default value to keep the parameter hidden from client code.
|
||||
Note that the second template argument was not given to <TT>enable_if</TT>, as the default
|
||||
<TT>void</TT> gives the desired behavior.<BR>
|
||||
<BR>
|
||||
Which way to write the enabler is largely a matter of taste, but for certain functions, only a
|
||||
subset of the options is possible:
|
||||
Whether to write the enabler as an argument or within the return type is
|
||||
largely a matter of taste, but for certain functions, only one
|
||||
alternative is possible:
|
||||
<UL><LI>
|
||||
Many operators have a fixed number of arguments, thus <TT>enable_if</TT> must be used either in the
|
||||
return type or in an extra template parameter.
|
||||
<LI>Functions that have a variadic parameter list must use either the return type form or an extra
|
||||
template parameter.
|
||||
<LI>Constructors do not have a return type so you must use either an extra function parameter or an
|
||||
extra template parameter.
|
||||
<LI>Constructors that have a variadic parameter list must an extra template parameter.
|
||||
<LI>Conversion operators can only be written with an extra template parameter.
|
||||
Operators have a fixed number of arguments, thus <TT>enable_if</TT> must be used in the return type.
|
||||
<LI>Constructors and destructors do not have a return type; an extra argument is the only option.
|
||||
<LI>There does not seem to be a way to specify an enabler for a conversion operator. Converting constructors,
|
||||
however, can have enablers as extra default arguments.
|
||||
</UL>
|
||||
<!--TOC subsection Enabling function templates in C++0x-->
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||||
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<A NAME="sec:enable_if_0x"></A>
|
||||
<H3><A NAME="htoc7">3.1</A> Enabling function templates in C++0x</H3><!--SEC END -->
|
||||
|
||||
In a compiler which supports C++0x default arguments for function template parameters, you can
|
||||
enable and disable function templates by adding an additional template parameter. This approach
|
||||
works in all situations where you would use either the return type form of <TT>enable_if</TT> or
|
||||
the function parameter form, including operators, constructors, variadic function templates, and
|
||||
even overloaded conversion operations.
|
||||
|
||||
As an example:
|
||||
|
||||
<PRE>#include <boost/type_traits/is_arithmetic.hpp>
|
||||
#include <boost/type_traits/is_pointer.hpp>
|
||||
#include <boost/utility/enable_if.hpp>
|
||||
|
||||
class test
|
||||
{
|
||||
public:
|
||||
// A constructor that works for any argument list of size 10
|
||||
template< class... T
|
||||
, typename boost::enable_if_c< sizeof...( T ) == 10, int >::type = 0
|
||||
>
|
||||
test( T&&... );
|
||||
|
||||
// A conversion operation that can convert to any arithmetic type
|
||||
template< class T
|
||||
, typename boost::enable_if< boost::is_arithmetic< T >, int >::type = 0
|
||||
>
|
||||
operator T() const;
|
||||
|
||||
// A conversion operation that can convert to any pointer type
|
||||
template< class T
|
||||
, typename boost::enable_if< boost::is_pointer< T >, int >::type = 0
|
||||
>
|
||||
operator T() const;
|
||||
};
|
||||
|
||||
int main()
|
||||
{
|
||||
// Works
|
||||
test test_( 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 );
|
||||
|
||||
// Fails as expected
|
||||
test fail_construction( 1, 2, 3, 4, 5 );
|
||||
|
||||
// Works by calling the conversion operator enabled for arithmetic types
|
||||
int arithmetic_object = test_;
|
||||
|
||||
// Works by calling the conversion operator enabled for pointer types
|
||||
int* pointer_object = test_;
|
||||
|
||||
// Fails as expected
|
||||
struct {} fail_conversion = test_;
|
||||
}
|
||||
|
||||
</PRE>
|
||||
|
||||
<!--TOC subsection Enabling template class specializations-->
|
||||
|
||||
<H3><A NAME="htoc7">3.2</A> Enabling template class specializations</H3><!--SEC END -->
|
||||
<H3><A NAME="htoc6">3.1</A> Enabling template class specializations</H3><!--SEC END -->
|
||||
|
||||
<A NAME="sec:enable_if_classes"></A>
|
||||
Class template specializations can be enabled or disabled with <TT>enable_if</TT>.
|
||||
@@ -285,7 +210,7 @@ is the correct value.<BR>
|
||||
<BR>
|
||||
<!--TOC subsection Overlapping enabler conditions-->
|
||||
|
||||
<H3><A NAME="htoc8">3.3</A> Overlapping enabler conditions</H3><!--SEC END -->
|
||||
<H3><A NAME="htoc7">3.2</A> Overlapping enabler conditions</H3><!--SEC END -->
|
||||
|
||||
<A NAME="sec:overlapping_conditions"></A>
|
||||
Once the compiler has examined the enabling conditions and included the
|
||||
@@ -314,7 +239,7 @@ partial specializations as well.<BR>
|
||||
<BR>
|
||||
<!--TOC subsection Lazy <TT>enable_if</TT>-->
|
||||
|
||||
<H3><A NAME="htoc9">3.4</A> Lazy <TT>enable_if</TT></H3><!--SEC END -->
|
||||
<H3><A NAME="htoc8">3.3</A> Lazy <TT>enable_if</TT></H3><!--SEC END -->
|
||||
|
||||
<A NAME="sec:enable_if_lazy"></A>
|
||||
In some cases it is necessary to avoid instantiating part of a
|
||||
@@ -360,7 +285,7 @@ above example, <TT>is_multipliable<T, U>::value</TT> defines when
|
||||
<BR>
|
||||
<!--TOC subsection Compiler workarounds-->
|
||||
|
||||
<H3><A NAME="htoc10">3.5</A> Compiler workarounds</H3><!--SEC END -->
|
||||
<H3><A NAME="htoc9">3.4</A> Compiler workarounds</H3><!--SEC END -->
|
||||
|
||||
<A NAME="sec:workarounds"></A>
|
||||
Some compilers flag functions as ambiguous if the only distinguishing factor is a different
|
||||
@@ -442,9 +367,9 @@ David Vandevoorde and Nicolai M. Josuttis.
|
||||
Addison-Wesley, 2002.</DL>
|
||||
|
||||
<hr/>
|
||||
<p>Copyright Jaakko Järvi<sup>*</sup>, Jeremiah Willcock<sup>*</sup>, Andrew Lumsdaine<sup>*</sup>, Matt Calabrese<BR>
|
||||
<EM>{jajarvi|jewillco|lums}@osl.iu.edu, rivorus@gmail.com</EM><BR>
|
||||
<sup>*</sup>Indiana University<BR>
|
||||
<p>Copyright Jaakko Järvi, Jeremiah Willcock and Andrew Lumsdaine<BR>
|
||||
<EM>{jajarvi|jewillco|lums}@osl.iu.edu</EM><BR>
|
||||
Indiana University<BR>
|
||||
Open Systems Lab<br/>
|
||||
Use, modification and distribution are subject to the
|
||||
Boost Software License, Version 1.0.
|
||||
@@ -461,4 +386,4 @@ or copy at <a href="http://www.boost.org/LICENSE_1_0.txt">
|
||||
</EM><A HREF="http://pauillac.inria.fr/~maranget/hevea/index.html"><EM>H<FONT SIZE=2><sup>E</sup></FONT>V<FONT SIZE=2><sup>E</sup></FONT>A</EM></A><EM>.
|
||||
</EM></BLOCKQUOTE>
|
||||
</BODY>
|
||||
</HTML>
|
||||
</HTML>
|
||||
@@ -1,31 +0,0 @@
|
||||
|
||||
# Copyright (C) 2009-2012 Lorenzo Caminiti
|
||||
# Distributed under the Boost Software License, Version 1.0
|
||||
# (see accompanying file LICENSE_1_0.txt or a copy at
|
||||
# http://www.boost.org/LICENSE_1_0.txt)
|
||||
# Home at http://www.boost.org/libs/utility/identity_type
|
||||
|
||||
import quickbook ;
|
||||
using boostbook ;
|
||||
|
||||
doxygen reference : ../../../../boost/utility/identity_type.hpp
|
||||
: <reftitle>"Reference"
|
||||
<doxygen:param>PREDEFINED="DOXYGEN"
|
||||
<doxygen:param>QUIET=YES
|
||||
<doxygen:param>WARN_IF_UNDOCUMENTED=NO
|
||||
<doxygen:param>HIDE_UNDOC_MEMBERS=YES
|
||||
<doxygen:param>HIDE_UNDOC_CLASSES=YES
|
||||
<doxygen:param>ALIASES=" Params=\"<b>Parameters:</b> <table border="0">\" Param{2}=\"<tr><td><b><tt>\\1</tt></b></td><td>\\2</td></tr>\" EndParams=\"</table>\" Returns=\"<b>Returns:</b>\" Note=\"<b>Note:</b>\" Warning=\"<b>Warning:</b>\" See=\"<b>See:</b>\" RefSect{2}=\"\\xmlonly<link linkend='boost_utility_identitytype.\\1'>\\2</link>\\endxmlonly\" RefClass{1}=\"\\xmlonly<computeroutput><classname alt='\\1'>\\1</classname></computeroutput>\\endxmlonly\" RefFunc{1}=\"\\xmlonly<computeroutput><functionname alt='\\1'>\\1</functionname></computeroutput>\\endxmlonly\" RefMacro{1}=\"\\xmlonly<computeroutput><macroname alt='\\1'>\\1</macroname></computeroutput>\\endxmlonly\" "
|
||||
;
|
||||
|
||||
# This target must be called "index" so to generate "index.html" file.
|
||||
xml index : identity_type.qbk : <dependency>reference ;
|
||||
|
||||
boostbook doc : index
|
||||
: <location>html
|
||||
<format>onehtml
|
||||
<xsl:param>toc.section.depth=0
|
||||
<xsl:param>html.stylesheet=../../../../../doc/src/boostbook.css
|
||||
<xsl:param>boost.root=../../../../..
|
||||
;
|
||||
|
||||
@@ -1,252 +0,0 @@
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Boost.Utility/IdentityType 1.0.0</title><link rel="stylesheet" type="text/css" href="../../../../../doc/src/boostbook.css"><meta name="generator" content="DocBook XSL Stylesheets V1.76.1"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="chapter" title="Boost.Utility/IdentityType 1.0.0"><div class="titlepage"><div><div><h2 class="title"><a name="boost_utility_identitytype"></a>Boost.Utility/IdentityType 1.0.0</h2></div><div><div class="author"><h3 class="author"><span class="firstname">Lorenzo</span> <span class="surname">Caminiti <code class="email"><<a class="email" href="mailto:lorcaminiti@gmail.com">lorcaminiti@gmail.com</a>></code></span></h3></div></div><div><p class="copyright">Copyright © 2009-2012 Lorenzo
|
||||
Caminiti</p></div><div><div class="legalnotice" title="Legal Notice"><a name="boost_utility_identitytype.legal"></a><p>
|
||||
Distributed under the Boost Software License, Version 1.0 (see accompanying
|
||||
file LICENSE_1_0.txt or a 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></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#boost_utility_identitytype.motivation">Motivation</a></span></dt><dt><span class="section"><a href="#boost_utility_identitytype.solution">Solution</a></span></dt><dt><span class="section"><a href="#boost_utility_identitytype.templates">Templates</a></span></dt><dt><span class="section"><a href="#boost_utility_identitytype.abstract_types">Abstract Types</a></span></dt><dt><span class="section"><a href="#boost_utility_identitytype.annex__usage">Annex: Usage</a></span></dt><dt><span class="section"><a href="#boost_utility_identitytype.annex__implementation">Annex:
|
||||
Implementation</a></span></dt><dt><span class="section"><a href="#reference">Reference</a></span></dt></dl></div><p>
|
||||
This library allows to wrap types within round parenthesis so they can always
|
||||
be passed as macro parameters.
|
||||
</p><div class="section boost_utility_identitytype_motivation" title="Motivation"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="boost_utility_identitytype.motivation"></a><a class="link" href="#boost_utility_identitytype.motivation" title="Motivation">Motivation</a></h2></div></div></div><p>
|
||||
Consider the following macro which declares a variable named <code class="computeroutput"><span class="identifier">var</span></code><code class="literal"><span class="emphasis"><em>n</em></span></code>
|
||||
with the specified <code class="literal"><span class="emphasis"><em>type</em></span></code> (see also
|
||||
<a href="../../test/var_error.cpp" target="_top"><code class="literal">var_error.cpp</code></a>):
|
||||
</p><p>
|
||||
</p><pre class="programlisting"><span class="preprocessor">#define</span> <span class="identifier">VAR</span><span class="special">(</span><span class="identifier">type</span><span class="special">,</span> <span class="identifier">n</span><span class="special">)</span> <span class="identifier">type</span> <span class="identifier">var</span> <span class="error">#</span><span class="preprocessor"># n</span>
|
||||
|
||||
<span class="identifier">VAR</span><span class="special">(</span><span class="keyword">int</span><span class="special">,</span> <span class="number">1</span><span class="special">);</span> <span class="comment">// OK.</span>
|
||||
<span class="identifier">VAR</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">char</span><span class="special">>,</span> <span class="number">2</span><span class="special">);</span> <span class="comment">// Error.</span>
|
||||
</pre><p>
|
||||
</p><p>
|
||||
The first macro invocation works correctly declaring a variable named <code class="computeroutput"><span class="identifier">var1</span></code> of type <code class="computeroutput"><span class="keyword">int</span></code>.
|
||||
However, the second macro invocation fails generating a preprocessor error
|
||||
similar to the following:
|
||||
</p><pre class="programlisting">error: macro "VAR" passed 3 arguments, but takes just 2
|
||||
</pre><p>
|
||||
That is because the <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span></code> type passed as the first macro parameter
|
||||
contains a comma <code class="computeroutput"><span class="special">,</span></code> not wrapped
|
||||
by round parenthesis <code class="computeroutput"><span class="special">()</span></code>. The preprocessor
|
||||
interprets that unwrapped comma as a separation between macro parameters concluding
|
||||
that a total of three (and not two) parameters are passed to the macro in the
|
||||
following order:
|
||||
</p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
|
||||
<code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span><span class="keyword">int</span></code>
|
||||
</li><li class="listitem">
|
||||
<code class="computeroutput"><span class="keyword">char</span><span class="special">></span></code>
|
||||
</li><li class="listitem">
|
||||
<code class="computeroutput"><span class="number">2</span></code>
|
||||
</li></ol></div><p>
|
||||
Note that, differently from the compiler, the preprocessor only recognizes
|
||||
round parenthesis <code class="computeroutput"><span class="special">()</span></code>. Angular
|
||||
<code class="computeroutput"><span class="special"><></span></code> and squared <code class="computeroutput"><span class="special">[]</span></code> parenthesis are not recognized by the preprocessor
|
||||
when parsing macro parameters.
|
||||
</p></div><div class="section boost_utility_identitytype_solution" title="Solution"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="boost_utility_identitytype.solution"></a><a class="link" href="#boost_utility_identitytype.solution" title="Solution">Solution</a></h2></div></div></div><p>
|
||||
In some cases, it might be possible to workaround this issue by avoiding to
|
||||
pass the type expression to the macro all together. For example, in the case
|
||||
above a <code class="computeroutput"><span class="keyword">typedef</span></code> could have been
|
||||
used to specify the type expression with the commas outside the macro (see
|
||||
also <a href="../../test/var.cpp" target="_top"><code class="literal">var.cpp</code></a>):
|
||||
</p><p>
|
||||
</p><pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">char</span><span class="special">></span> <span class="identifier">map_type</span><span class="special">;</span>
|
||||
<span class="identifier">VAR</span><span class="special">(</span><span class="identifier">map_type</span><span class="special">,</span> <span class="number">3</span><span class="special">);</span> <span class="comment">// OK.</span>
|
||||
</pre><p>
|
||||
</p><p>
|
||||
When this is neither possible nor desired (e.g., see the function template
|
||||
<code class="computeroutput"><span class="identifier">f</span></code> in the section below), this
|
||||
library header <code class="computeroutput"><a class="link" href="#header.boost.utility.identity_type_hpp" title="Header <boost/utility/identity_type.hpp>">boost/utility/identity_type.hpp</a></code>
|
||||
defines a macro <code class="computeroutput"><a class="link" href="#BOOST_IDENTITY_TYPE" title="Macro BOOST_IDENTITY_TYPE">BOOST_IDENTITY_TYPE</a></code>
|
||||
which can be used to workaround the issue while keeping the type expression
|
||||
as one of the macro parameters (see also <a href="../../test/var.cpp" target="_top"><code class="literal">var.cpp</code></a>).
|
||||
</p><p>
|
||||
</p><pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">utility</span><span class="special">/</span><span class="identifier">identity_type</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
|
||||
|
||||
<span class="identifier">VAR</span><span class="special">(</span><span class="identifier">BOOST_IDENTITY_TYPE</span><span class="special">((</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">char</span><span class="special">>)),</span> <span class="number">4</span><span class="special">);</span> <span class="comment">// OK.</span>
|
||||
</pre><p>
|
||||
</p><p>
|
||||
The <code class="computeroutput"><a class="link" href="#BOOST_IDENTITY_TYPE" title="Macro BOOST_IDENTITY_TYPE">BOOST_IDENTITY_TYPE</a></code> macro
|
||||
expands to an expression that evaluates (at compile-time) to the specified
|
||||
type. The specified type is never split into multiple macro parameters because
|
||||
it is always wrapped by a set of extra round parenthesis <code class="computeroutput"><span class="special">()</span></code>.
|
||||
In fact, a total of two sets of round parenthesis must be used: The parenthesis
|
||||
to invoke the macro <code class="computeroutput"><span class="identifier">BOOST_IDENTITY_TYPE</span><span class="special">(...)</span></code> plus the inner parenthesis to wrap the
|
||||
type passed to the macro <code class="computeroutput"><span class="identifier">BOOST_IDENTITY_TYPE</span><span class="special">((...))</span></code>.
|
||||
</p><p>
|
||||
This macro works on any <a href="http://www.open-std.org/JTC1/SC22/WG21/docs/standards" target="_top">C++03</a>
|
||||
compiler (and it does not use <a href="http://en.wikipedia.org/wiki/Variadic_macro" target="_top">variadic
|
||||
macros</a>). <sup>[<a name="boost_utility_identitytype.solution.f0" href="#ftn.boost_utility_identitytype.solution.f0" class="footnote">1</a>]</sup> The authors originally developed and tested this library using
|
||||
GNU Compiler Collection (GCC) C++ 4.5.3 (with and without C++11 features enabled
|
||||
<code class="computeroutput"><span class="special">-</span><span class="identifier">std</span><span class="special">=</span><span class="identifier">c</span><span class="special">++</span><span class="number">0</span><span class="identifier">x</span></code>) on Cygwin
|
||||
and Miscrosoft Visual C++ (MSVC) 8.0 on Windows 7. See the library <a href="http://www.boost.org/development/tests/release/developer/utility-identity_type.html" target="_top">regressions
|
||||
test results</a> for more information on supported compilers and platforms.
|
||||
</p></div><div class="section boost_utility_identitytype_templates" title="Templates"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="boost_utility_identitytype.templates"></a><a class="link" href="#boost_utility_identitytype.templates" title="Templates">Templates</a></h2></div></div></div><p>
|
||||
This macro must be prefixed by <code class="computeroutput"><span class="keyword">typename</span></code>
|
||||
when used within templates. For example, let's program a macro that declares
|
||||
a function parameter named <code class="computeroutput"><span class="identifier">arg</span></code><code class="literal"><span class="emphasis"><em>n</em></span></code>
|
||||
with the specified <code class="literal"><span class="emphasis"><em>type</em></span></code> (see also
|
||||
<a href="../../test/template.cpp" target="_top"><code class="literal">template.cpp</code></a>):
|
||||
</p><p>
|
||||
</p><pre class="programlisting"><span class="preprocessor">#define</span> <span class="identifier">ARG</span><span class="special">(</span><span class="identifier">type</span><span class="special">,</span> <span class="identifier">n</span><span class="special">)</span> <span class="identifier">type</span> <span class="identifier">arg</span> <span class="error">#</span><span class="preprocessor"># n</span>
|
||||
|
||||
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">></span>
|
||||
<span class="keyword">void</span> <span class="identifier">f</span><span class="special">(</span> <span class="comment">// Prefix macro with `typename` in templates.</span>
|
||||
<span class="identifier">ARG</span><span class="special">(</span><span class="keyword">typename</span> <span class="identifier">BOOST_IDENTITY_TYPE</span><span class="special">((</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span><span class="keyword">int</span><span class="special">,</span> <span class="identifier">T</span><span class="special">>)),</span> <span class="number">1</span><span class="special">)</span>
|
||||
<span class="special">)</span> <span class="special">{</span>
|
||||
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">arg1</span><span class="special">[</span><span class="number">0</span><span class="special">]</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
|
||||
<span class="special">}</span>
|
||||
</pre><p>
|
||||
</p><p>
|
||||
</p><pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">char</span><span class="special">></span> <span class="identifier">a</span><span class="special">;</span>
|
||||
<span class="identifier">a</span><span class="special">[</span><span class="number">0</span><span class="special">]</span> <span class="special">=</span> <span class="char">'a'</span><span class="special">;</span>
|
||||
|
||||
<span class="identifier">f</span><span class="special"><</span><span class="keyword">char</span><span class="special">>(</span><span class="identifier">a</span><span class="special">);</span> <span class="comment">// OK...</span>
|
||||
<span class="comment">// f(a); // ... but error.</span>
|
||||
</pre><p>
|
||||
</p><p>
|
||||
However, note that the template parameter <code class="computeroutput"><span class="keyword">char</span></code>
|
||||
must be manually specified when invoking the function as in <code class="computeroutput"><span class="identifier">f</span><span class="special"><</span><span class="keyword">char</span><span class="special">>(</span><span class="identifier">a</span><span class="special">)</span></code>. In fact,
|
||||
when the <code class="computeroutput"><a class="link" href="#BOOST_IDENTITY_TYPE" title="Macro BOOST_IDENTITY_TYPE">BOOST_IDENTITY_TYPE</a></code>
|
||||
macro is used to wrap a function template parameter, the template parameter
|
||||
can no longer be automatically deduced by the compiler form the function call
|
||||
as <code class="computeroutput"><span class="identifier">f</span><span class="special">(</span><span class="identifier">a</span><span class="special">)</span></code> would
|
||||
have done. <sup>[<a name="boost_utility_identitytype.templates.f0" href="#ftn.boost_utility_identitytype.templates.f0" class="footnote">2</a>]</sup> (This limitation does not apply to class templates because class
|
||||
template parameters must always be explicitly specified.) In other words, without
|
||||
using the <code class="computeroutput"><a class="link" href="#BOOST_IDENTITY_TYPE" title="Macro BOOST_IDENTITY_TYPE">BOOST_IDENTITY_TYPE</a></code>
|
||||
macro, C++ would normally be able to automatically deduce the function template
|
||||
parameter as shown below:
|
||||
</p><p>
|
||||
</p><pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">></span>
|
||||
<span class="keyword">void</span> <span class="identifier">g</span><span class="special">(</span>
|
||||
<span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span><span class="keyword">int</span><span class="special">,</span> <span class="identifier">T</span><span class="special">></span> <span class="identifier">arg1</span>
|
||||
<span class="special">)</span> <span class="special">{</span>
|
||||
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">arg1</span><span class="special">[</span><span class="number">0</span><span class="special">]</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
|
||||
<span class="special">}</span>
|
||||
</pre><p>
|
||||
</p><p>
|
||||
</p><pre class="programlisting"><span class="identifier">g</span><span class="special"><</span><span class="keyword">char</span><span class="special">>(</span><span class="identifier">a</span><span class="special">);</span> <span class="comment">// OK...</span>
|
||||
<span class="identifier">g</span><span class="special">(</span><span class="identifier">a</span><span class="special">);</span> <span class="comment">// ... and also OK.</span>
|
||||
</pre><p>
|
||||
</p></div><div class="section boost_utility_identitytype_abstract_types" title="Abstract Types"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="boost_utility_identitytype.abstract_types"></a><a class="link" href="#boost_utility_identitytype.abstract_types" title="Abstract Types">Abstract Types</a></h2></div></div></div><p>
|
||||
On some compilers (e.g., GCC), using this macro on abstract types (i.e., classes
|
||||
with one or more pure virtual functions) generates a compiler error. This can
|
||||
be avoided by manipulating the type adding and removing a reference to it.
|
||||
</p><p>
|
||||
Let's program a macro that performs a static assertion on a <a href="http://en.wikipedia.org/wiki/Template_metaprogramming" target="_top">Template
|
||||
Meta-Programming</a> (TMP) meta-function (similarly to Boost.MPL <a href="http://www.boost.org/doc/libs/1_36_0/libs/mpl/doc/refmanual/assert.html" target="_top"><code class="computeroutput"><span class="identifier">BOOST_MPL_ASSERT</span></code></a>). The <code class="computeroutput"><a class="link" href="#BOOST_IDENTITY_TYPE" title="Macro BOOST_IDENTITY_TYPE">BOOST_IDENTITY_TYPE</a></code> macro can be used
|
||||
to pass a meta-function with multiple template parameters to the assert macro
|
||||
(so to handle the commas separating the template parameters). In this case,
|
||||
if the meta-function is an abstract type, it needs to be manipulated adding
|
||||
and removing a reference to it (see also <a href="../../test/abstract.cpp" target="_top"><code class="literal">abstract.cpp</code></a>):
|
||||
</p><p>
|
||||
</p><pre class="programlisting"><span class="preprocessor">#define</span> <span class="identifier">TMP_ASSERT</span><span class="special">(</span><span class="identifier">metafunction</span><span class="special">)</span> <span class="special">\</span>
|
||||
<span class="identifier">BOOST_STATIC_ASSERT</span><span class="special">(</span><span class="identifier">metafunction</span><span class="special">::</span><span class="identifier">value</span><span class="special">)</span>
|
||||
|
||||
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">b</span><span class="special">></span>
|
||||
<span class="keyword">struct</span> <span class="identifier">abstract</span> <span class="special">{</span>
|
||||
<span class="keyword">static</span> <span class="keyword">const</span> <span class="keyword">bool</span> <span class="identifier">value</span> <span class="special">=</span> <span class="identifier">b</span><span class="special">;</span>
|
||||
<span class="keyword">virtual</span> <span class="keyword">void</span> <span class="identifier">f</span><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">x</span><span class="special">)</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> <span class="comment">// Pure virtual function.</span>
|
||||
<span class="special">};</span>
|
||||
|
||||
<span class="identifier">TMP_ASSERT</span><span class="special">(</span>
|
||||
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">remove_reference</span><span class="special"><</span> <span class="comment">// Add and remove</span>
|
||||
<span class="identifier">BOOST_IDENTITY_TYPE</span><span class="special">((</span> <span class="comment">// reference for</span>
|
||||
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">add_reference</span><span class="special"><</span> <span class="comment">// abstract type.</span>
|
||||
<span class="identifier">abstract</span><span class="special"><</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">true</span><span class="special">></span>
|
||||
<span class="special">>::</span><span class="identifier">type</span>
|
||||
<span class="special">))</span>
|
||||
<span class="special">>::</span><span class="identifier">type</span>
|
||||
<span class="special">);</span>
|
||||
</pre><p>
|
||||
</p></div><div class="section boost_utility_identitytype_annex__usage" title="Annex: Usage"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="boost_utility_identitytype.annex__usage"></a><a class="link" href="#boost_utility_identitytype.annex__usage" title="Annex: Usage">Annex: Usage</a></h2></div></div></div><p>
|
||||
The <code class="computeroutput"><a class="link" href="#BOOST_IDENTITY_TYPE" title="Macro BOOST_IDENTITY_TYPE">BOOST_IDENTITY_TYPE</a></code> macro
|
||||
can be used either when calling a user-defined macro (as shown by the examples
|
||||
so far), or internally when implementing a user-defined macro (as shown below).
|
||||
When <code class="computeroutput"><a class="link" href="#BOOST_IDENTITY_TYPE" title="Macro BOOST_IDENTITY_TYPE">BOOST_IDENTITY_TYPE</a></code> is
|
||||
used in the implementation of the user-defined macro, the caller of the user
|
||||
macro will have to specify the extra parenthesis (see also <a href="../../test/paren.cpp" target="_top"><code class="literal">paren.cpp</code></a>):
|
||||
</p><p>
|
||||
</p><pre class="programlisting"><span class="preprocessor">#define</span> <span class="identifier">TMP_ASSERT_PAREN</span><span class="special">(</span><span class="identifier">parenthesized_metafunction</span><span class="special">)</span> <span class="special">\</span>
|
||||
<span class="comment">/* use `BOOST_IDENTITY_TYPE` in macro definition instead of invocation */</span> <span class="special">\</span>
|
||||
<span class="identifier">BOOST_STATIC_ASSERT</span><span class="special">(</span><span class="identifier">BOOST_IDENTITY_TYPE</span><span class="special">(</span><span class="identifier">parenthesized_metafunction</span><span class="special">)::</span><span class="identifier">value</span><span class="special">)</span>
|
||||
|
||||
<span class="preprocessor">#define</span> <span class="identifier">TMP_ASSERT</span><span class="special">(</span><span class="identifier">metafunction</span><span class="special">)</span> <span class="special">\</span>
|
||||
<span class="identifier">BOOST_STATIC_ASSERT</span><span class="special">(</span><span class="identifier">metafunction</span><span class="special">::</span><span class="identifier">value</span><span class="special">)</span>
|
||||
|
||||
<span class="comment">// Specify only extra parenthesis `((...))`.</span>
|
||||
<span class="identifier">TMP_ASSERT_PAREN</span><span class="special">((</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">is_const</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">char</span><span class="special">></span> <span class="keyword">const</span><span class="special">>));</span>
|
||||
|
||||
<span class="comment">// Specify both the extra parenthesis `((...))` and `BOOST_IDENTITY_TYPE` macro.</span>
|
||||
<span class="identifier">TMP_ASSERT</span><span class="special">(</span><span class="identifier">BOOST_IDENTITY_TYPE</span><span class="special">((</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">is_const</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">char</span><span class="special">></span> <span class="keyword">const</span><span class="special">>)));</span>
|
||||
</pre><p>
|
||||
</p><p>
|
||||
However, note that the caller will <span class="emphasis"><em>always</em></span> have to specify
|
||||
the extra parenthesis even when the macro parameters contain no comma:
|
||||
</p><p>
|
||||
</p><pre class="programlisting"><span class="identifier">TMP_ASSERT_PAREN</span><span class="special">((</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">is_const</span><span class="special"><</span><span class="keyword">int</span> <span class="keyword">const</span><span class="special">>));</span> <span class="comment">// Always extra `((...))`.</span>
|
||||
|
||||
<span class="identifier">TMP_ASSERT</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">is_const</span><span class="special"><</span><span class="keyword">int</span> <span class="keyword">const</span><span class="special">>);</span> <span class="comment">// No extra `((...))` and no macro.</span>
|
||||
</pre><p>
|
||||
</p><p>
|
||||
In some cases, using <code class="computeroutput"><a class="link" href="#BOOST_IDENTITY_TYPE" title="Macro BOOST_IDENTITY_TYPE">BOOST_IDENTITY_TYPE</a></code>
|
||||
in the implementation of the user-defined macro might provide the best syntax
|
||||
for the caller. For example, this is the case for <code class="computeroutput"><span class="identifier">BOOST_MPL_ASSERT</span></code>
|
||||
because the majority of template meta-programming expressions contain unwrapped
|
||||
commas so it is less confusing for the user to always specify the extra parenthesis
|
||||
<code class="computeroutput"><span class="special">((...))</span></code> instead of using <code class="computeroutput"><a class="link" href="#BOOST_IDENTITY_TYPE" title="Macro BOOST_IDENTITY_TYPE">BOOST_IDENTITY_TYPE</a></code>:
|
||||
</p><pre class="programlisting"><span class="identifier">BOOST_MPL_ASSERT</span><span class="special">((</span> <span class="comment">// Natural syntax.</span>
|
||||
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">mpl</span><span class="special">::</span><span class="identifier">and_</span><span class="special"><</span>
|
||||
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">is_const</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span>
|
||||
<span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">is_reference</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span>
|
||||
<span class="special">></span>
|
||||
<span class="special">));</span>
|
||||
</pre><p>
|
||||
However, in other situations it might be preferable to not require the extra
|
||||
parenthesis in the common cases and handle commas as special cases using <code class="computeroutput"><a class="link" href="#BOOST_IDENTITY_TYPE" title="Macro BOOST_IDENTITY_TYPE">BOOST_IDENTITY_TYPE</a></code>. For example, this
|
||||
is the case for <a href="http://www.boost.org/libs/local_function" target="_top"><code class="computeroutput"><span class="identifier">BOOST_LOCAL_FUNCTION</span></code></a> for which always
|
||||
requiring the extra parenthesis <code class="computeroutput"><span class="special">((...))</span></code>
|
||||
around the types would lead to an unnatural syntax for the local function signature:
|
||||
</p><pre class="programlisting"><span class="keyword">int</span> <span class="identifier">BOOST_LOCAL_FUNCTION</span><span class="special">(</span> <span class="special">((</span><span class="keyword">int</span><span class="special">&))</span> <span class="identifier">x</span><span class="special">,</span> <span class="special">((</span><span class="keyword">int</span><span class="special">&))</span> <span class="identifier">y</span> <span class="special">)</span> <span class="special">{</span> <span class="comment">// Unnatural syntax.</span>
|
||||
<span class="keyword">return</span> <span class="identifier">x</span> <span class="special">+</span> <span class="identifier">y</span><span class="special">;</span>
|
||||
<span class="special">}</span> <span class="identifier">BOOST_LOCAL_FUNCTION_NAME</span><span class="special">(</span><span class="identifier">add</span><span class="special">)</span>
|
||||
</pre><p>
|
||||
Instead requiring the user to specify <code class="computeroutput"><a class="link" href="#BOOST_IDENTITY_TYPE" title="Macro BOOST_IDENTITY_TYPE">BOOST_IDENTITY_TYPE</a></code>
|
||||
only when needed allows for the more natural syntax <code class="computeroutput"><span class="identifier">BOOST_LOCAL_FUNCTION</span><span class="special">(</span><span class="keyword">int</span><span class="special">&</span>
|
||||
<span class="identifier">x</span><span class="special">,</span> <span class="keyword">int</span><span class="special">&</span> <span class="identifier">y</span><span class="special">)</span></code> in the common cases when the parameter types
|
||||
contain no comma (while still allowing to specify parameter types with commas
|
||||
as special cases using <code class="computeroutput"><span class="identifier">BOOST_LOCAL_FUNCTION</span><span class="special">(</span><span class="identifier">BOOST_IDENTITY_TYPE</span><span class="special">((</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">char</span><span class="special">>))&</span>
|
||||
<span class="identifier">x</span><span class="special">,</span> <span class="keyword">int</span><span class="special">&</span> <span class="identifier">y</span><span class="special">)</span></code>).
|
||||
</p></div><div class="section boost_utility_identitytype_annex__implementation" title="Annex: Implementation"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="boost_utility_identitytype.annex__implementation"></a><a class="link" href="#boost_utility_identitytype.annex__implementation" title="Annex: Implementation">Annex:
|
||||
Implementation</a></h2></div></div></div><p>
|
||||
The implementation of this library macro is equivalent to the following: <sup>[<a name="boost_utility_identitytype.annex__implementation.f0" href="#ftn.boost_utility_identitytype.annex__implementation.f0" class="footnote">3</a>]</sup>
|
||||
</p><pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">type_traits</span><span class="special">/</span><span class="identifier">function_traits</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
|
||||
|
||||
<span class="preprocessor">#define</span> <span class="identifier">BOOST_IDENTITY_TYPE</span><span class="special">(</span><span class="identifier">parenthesized_type</span><span class="special">)</span> <span class="special">\</span>
|
||||
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">function_traits</span><span class="special"><</span><span class="keyword">void</span> <span class="identifier">parenthesized_type</span><span class="special">>::</span><span class="identifier">arg1_type</span>
|
||||
</pre><p>
|
||||
Essentially, the type is wrapped between round parenthesis <code class="computeroutput"><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span><span class="keyword">int</span><span class="special">,</span>
|
||||
<span class="keyword">char</span><span class="special">>)</span></code>
|
||||
so it can be passed as a single macro parameter even if it contains commas.
|
||||
Then the parenthesized type is transformed into the type of a function returning
|
||||
<code class="computeroutput"><span class="keyword">void</span></code> and with the specified type
|
||||
as the type of the first and only argument <code class="computeroutput"><span class="keyword">void</span>
|
||||
<span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">char</span><span class="special">>)</span></code>. Finally, the type of the first argument
|
||||
<code class="computeroutput"><span class="identifier">arg1_type</span></code> is extracted at compile-time
|
||||
using the <code class="computeroutput"><span class="identifier">function_traits</span></code> meta-function
|
||||
therefore obtaining the original type from the parenthesized type (effectively
|
||||
stripping the extra parenthesis from around the specified type).
|
||||
</p></div><div class="section reference" title="Reference"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="reference"></a>Reference</h2></div></div></div><div class="section header_boost_utility_identity_type_hpp" title="Header <boost/utility/identity_type.hpp>"><div class="titlepage"><div><div><h3 class="title"><a name="header.boost.utility.identity_type_hpp"></a>Header <<a href="../../../../../boost/utility/identity_type.hpp" target="_top">boost/utility/identity_type.hpp</a>></h3></div></div></div><p>Wrap type expressions with round parenthesis so they can be passed to macros even if they contain commas. </p><pre class="synopsis">
|
||||
|
||||
<a class="link" href="#BOOST_IDENTITY_TYPE" title="Macro BOOST_IDENTITY_TYPE">BOOST_IDENTITY_TYPE</a>(parenthesized_type)</pre><div class="refentry" title="Macro BOOST_IDENTITY_TYPE"><a name="BOOST_IDENTITY_TYPE"></a><div class="titlepage"></div><div class="refnamediv"><h2><span class="refentrytitle">Macro BOOST_IDENTITY_TYPE</span></h2><p>BOOST_IDENTITY_TYPE — This macro allows to wrap the specified type expression within extra round parenthesis so the type can be passed as a single macro parameter even if it contains commas (not already wrapped within round parenthesis). </p></div><h2 class="refsynopsisdiv-title">Synopsis</h2><div class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: <<a class="link" href="#header.boost.utility.identity_type_hpp" title="Header <boost/utility/identity_type.hpp>">boost/utility/identity_type.hpp</a>>
|
||||
|
||||
</span>BOOST_IDENTITY_TYPE(parenthesized_type)</pre></div><div class="refsect1" title="Description"><a name="id554262"></a><h2>Description</h2><p><span class="bold"><strong>Parameters:</strong></span> </p><div class="informaltable"><table class="table"><colgroup><col><col></colgroup><tbody><tr><td><span class="bold"><strong><code class="computeroutput">parenthesized_type</code></strong></span></td><td>The type expression to be passed as macro parameter wrapped by a single set of round parenthesis <code class="computeroutput">(...)</code>. This type expression can contain an arbitrary number of commas. </td></tr></tbody></table></div><p>
|
||||
</p><p>This macro works on any C++03 compiler (it does not use variadic macros).</p><p>This macro must be prefixed by <code class="computeroutput">typename</code> when used within templates. Note that the compiler will not be able to automatically determine function template parameters when they are wrapped with this macro (these parameters need to be explicitly specified when calling the function template).</p><p>On some compilers (like GCC), using this macro on abstract types requires to add and remove a reference to the specified type. </p></div></div></div></div><div class="footnotes"><br><hr width="100" align="left"><div class="footnote"><p><sup>[<a id="ftn.boost_utility_identitytype.solution.f0" href="#boost_utility_identitytype.solution.f0" class="para">1</a>] </sup>
|
||||
Using variadic macros, it would be possible to require a single set of extra
|
||||
parenthesis <code class="computeroutput"><span class="identifier">BOOST_IDENTITY_TYPE</span><span class="special">(</span></code><code class="literal"><span class="emphasis"><em>type</em></span></code><code class="computeroutput"><span class="special">)</span></code> instead of two <code class="computeroutput"><span class="identifier">BOOST_IDENTITY_TYPE</span><span class="special">((</span></code><code class="literal"><span class="emphasis"><em>type</em></span></code><code class="computeroutput"><span class="special">))</span></code> but variadic macros are not part of C++03
|
||||
(even if nowadays they are supported by most modern compilers and they are
|
||||
also part of C++11).
|
||||
</p></div><div class="footnote"><p><sup>[<a id="ftn.boost_utility_identitytype.templates.f0" href="#boost_utility_identitytype.templates.f0" class="para">2</a>] </sup>
|
||||
This is because the implementation of <code class="computeroutput"><a class="link" href="#BOOST_IDENTITY_TYPE" title="Macro BOOST_IDENTITY_TYPE">BOOST_IDENTITY_TYPE</a></code>
|
||||
wraps the specified type within a meta-function.
|
||||
</p></div><div class="footnote"><p><sup>[<a id="ftn.boost_utility_identitytype.annex__implementation.f0" href="#boost_utility_identitytype.annex__implementation.f0" class="para">3</a>] </sup>
|
||||
There is absolutely no guarantee that the macro is actually implemented using
|
||||
the code listed in this documentation. The listed code is for explanatory
|
||||
purposes only.
|
||||
</p></div></div></div></body></html>
|
||||
@@ -1,165 +0,0 @@
|
||||
|
||||
[/ Copyright (C) 2009-2012 Lorenzo Caminiti ]
|
||||
[/ Distributed under the Boost Software License, Version 1.0 ]
|
||||
[/ (see accompanying file LICENSE_1_0.txt or a copy at ]
|
||||
[/ http://www.boost.org/LICENSE_1_0.txt) ]
|
||||
[/ Home at http://www.boost.org/libs/utility/identity_type ]
|
||||
|
||||
[library Boost.Utility/IdentityType
|
||||
[quickbook 1.5]
|
||||
[version 1.0.0]
|
||||
[copyright 2009-2012 Lorenzo Caminiti]
|
||||
[purpose wraps types with round parenthesis]
|
||||
[license
|
||||
Distributed under the Boost Software License, Version 1.0
|
||||
(see accompanying file LICENSE_1_0.txt or a copy at
|
||||
[@http://www.boost.org/LICENSE_1_0.txt])
|
||||
]
|
||||
[authors [Caminiti <email>lorcaminiti@gmail.com</email>, Lorenzo]]
|
||||
[category Utilities]
|
||||
]
|
||||
|
||||
This library allows to wrap types within round parenthesis so they can always be passed as macro parameters.
|
||||
|
||||
[import ../test/var_error.cpp]
|
||||
[import ../test/var.cpp]
|
||||
[import ../test/template.cpp]
|
||||
[import ../test/abstract.cpp]
|
||||
[import ../test/paren.cpp]
|
||||
|
||||
[section Motivation]
|
||||
|
||||
Consider the following macro which declares a variable named `var`[^['n]] with the specified [^['type]] (see also [@../../test/var_error.cpp =var_error.cpp=]):
|
||||
|
||||
[var_error]
|
||||
|
||||
The first macro invocation works correctly declaring a variable named `var1` of type `int`.
|
||||
However, the second macro invocation fails generating a preprocessor error similar to the following:
|
||||
|
||||
[pre
|
||||
error: macro "VAR" passed 3 arguments, but takes just 2
|
||||
]
|
||||
|
||||
That is because the `std::map` type passed as the first macro parameter contains a comma `,` not wrapped by round parenthesis `()`.
|
||||
The preprocessor interprets that unwrapped comma as a separation between macro parameters concluding that a total of three (and not two) parameters are passed to the macro in the following order:
|
||||
|
||||
# `std::map<int`
|
||||
# `char>`
|
||||
# `2`
|
||||
|
||||
Note that, differently from the compiler, the preprocessor only recognizes round parenthesis `()`.
|
||||
Angular `<>` and squared `[]` parenthesis are not recognized by the preprocessor when parsing macro parameters.
|
||||
|
||||
[endsect]
|
||||
|
||||
[section Solution]
|
||||
|
||||
In some cases, it might be possible to workaround this issue by avoiding to pass the type expression to the macro all together.
|
||||
For example, in the case above a `typedef` could have been used to specify the type expression with the commas outside the macro (see also [@../../test/var.cpp =var.cpp=]):
|
||||
|
||||
[var_typedef]
|
||||
|
||||
When this is neither possible nor desired (e.g., see the function template `f` in the section below), this library header [headerref boost/utility/identity_type.hpp] defines a macro [macroref BOOST_IDENTITY_TYPE] which can be used to workaround the issue while keeping the type expression as one of the macro parameters (see also [@../../test/var.cpp =var.cpp=]).
|
||||
|
||||
[var_ok]
|
||||
|
||||
The [macroref BOOST_IDENTITY_TYPE] macro expands to an expression that evaluates (at compile-time) to the specified type.
|
||||
The specified type is never split into multiple macro parameters because it is always wrapped by a set of extra round parenthesis `()`.
|
||||
In fact, a total of two sets of round parenthesis must be used: The parenthesis to invoke the macro `BOOST_IDENTITY_TYPE(...)` plus the inner parenthesis to wrap the type passed to the macro `BOOST_IDENTITY_TYPE((...))`.
|
||||
|
||||
This macro works on any [@http://www.open-std.org/JTC1/SC22/WG21/docs/standards C++03] compiler (and it does not use [@http://en.wikipedia.org/wiki/Variadic_macro variadic macros]).
|
||||
[footnote
|
||||
Using variadic macros, it would be possible to require a single set of extra parenthesis `BOOST_IDENTITY_TYPE(`[^['type]]`)` instead of two `BOOST_IDENTITY_TYPE((`[^['type]]`))` but variadic macros are not part of C++03 (even if nowadays they are supported by most modern compilers and they are also part of C++11).
|
||||
]
|
||||
The authors originally developed and tested this library using GNU Compiler Collection (GCC) C++ 4.5.3 (with and without C++11 features enabled `-std=c++0x`) on Cygwin and Miscrosoft Visual C++ (MSVC) 8.0 on Windows 7.
|
||||
See the library [@http://www.boost.org/development/tests/release/developer/utility-identity_type.html regressions test results] for more information on supported compilers and platforms.
|
||||
|
||||
[endsect]
|
||||
|
||||
[section Templates]
|
||||
|
||||
This macro must be prefixed by `typename` when used within templates.
|
||||
For example, let's program a macro that declares a function parameter named `arg`[^['n]] with the specified [^['type]] (see also [@../../test/template.cpp =template.cpp=]):
|
||||
|
||||
[template_f_decl]
|
||||
[template_f_call]
|
||||
|
||||
However, note that the template parameter `char` must be manually specified when invoking the function as in `f<char>(a)`.
|
||||
In fact, when the [macroref BOOST_IDENTITY_TYPE] macro is used to wrap a function template parameter, the template parameter can no longer be automatically deduced by the compiler form the function call as `f(a)` would have done.
|
||||
[footnote
|
||||
This is because the implementation of [macroref BOOST_IDENTITY_TYPE] wraps the specified type within a meta-function.
|
||||
]
|
||||
(This limitation does not apply to class templates because class template parameters must always be explicitly specified.)
|
||||
In other words, without using the [macroref BOOST_IDENTITY_TYPE] macro, C++ would normally be able to automatically deduce the function template parameter as shown below:
|
||||
|
||||
[template_g_decl]
|
||||
[template_g_call]
|
||||
|
||||
[endsect]
|
||||
|
||||
[section Abstract Types]
|
||||
|
||||
On some compilers (e.g., GCC), using this macro on abstract types (i.e., classes with one or more pure virtual functions) generates a compiler error.
|
||||
This can be avoided by manipulating the type adding and removing a reference to it.
|
||||
|
||||
Let's program a macro that performs a static assertion on a [@http://en.wikipedia.org/wiki/Template_metaprogramming Template Meta-Programming] (TMP) meta-function (similarly to Boost.MPL [@http://www.boost.org/doc/libs/1_36_0/libs/mpl/doc/refmanual/assert.html `BOOST_MPL_ASSERT`]).
|
||||
The [macroref BOOST_IDENTITY_TYPE] macro can be used to pass a meta-function with multiple template parameters to the assert macro (so to handle the commas separating the template parameters).
|
||||
In this case, if the meta-function is an abstract type, it needs to be manipulated adding and removing a reference to it (see also [@../../test/abstract.cpp =abstract.cpp=]):
|
||||
|
||||
[abstract]
|
||||
|
||||
[endsect]
|
||||
|
||||
[section Annex: Usage]
|
||||
|
||||
The [macroref BOOST_IDENTITY_TYPE] macro can be used either when calling a user-defined macro (as shown by the examples so far), or internally when implementing a user-defined macro (as shown below).
|
||||
When [macroref BOOST_IDENTITY_TYPE] is used in the implementation of the user-defined macro, the caller of the user macro will have to specify the extra parenthesis (see also [@../../test/paren.cpp =paren.cpp=]):
|
||||
|
||||
[paren]
|
||||
|
||||
However, note that the caller will /always/ have to specify the extra parenthesis even when the macro parameters contain no comma:
|
||||
|
||||
[paren_always]
|
||||
|
||||
In some cases, using [macroref BOOST_IDENTITY_TYPE] in the implementation of the user-defined macro might provide the best syntax for the caller.
|
||||
For example, this is the case for `BOOST_MPL_ASSERT` because the majority of template meta-programming expressions contain unwrapped commas so it is less confusing for the user to always specify the extra parenthesis `((...))` instead of using [macroref BOOST_IDENTITY_TYPE]:
|
||||
|
||||
BOOST_MPL_ASSERT(( // Natural syntax.
|
||||
boost::mpl::and_<
|
||||
boost::is_const<T>
|
||||
, boost::is_reference<T>
|
||||
>
|
||||
));
|
||||
|
||||
However, in other situations it might be preferable to not require the extra parenthesis in the common cases and handle commas as special cases using [macroref BOOST_IDENTITY_TYPE].
|
||||
For example, this is the case for [@http://www.boost.org/libs/local_function `BOOST_LOCAL_FUNCTION`] for which always requiring the extra parenthesis `((...))` around the types would lead to an unnatural syntax for the local function signature:
|
||||
|
||||
int BOOST_LOCAL_FUNCTION( ((int&)) x, ((int&)) y ) { // Unnatural syntax.
|
||||
return x + y;
|
||||
} BOOST_LOCAL_FUNCTION_NAME(add)
|
||||
|
||||
Instead requiring the user to specify [macroref BOOST_IDENTITY_TYPE] only when needed allows for the more natural syntax `BOOST_LOCAL_FUNCTION(int& x, int& y)` in the common cases when the parameter types contain no comma (while still allowing to specify parameter types with commas as special cases using `BOOST_LOCAL_FUNCTION(BOOST_IDENTITY_TYPE((std::map<int, char>))& x, int& y)`).
|
||||
|
||||
[endsect]
|
||||
|
||||
[section Annex: Implementation]
|
||||
|
||||
The implementation of this library macro is equivalent to the following:
|
||||
[footnote
|
||||
There is absolutely no guarantee that the macro is actually implemented using the code listed in this documentation.
|
||||
The listed code is for explanatory purposes only.
|
||||
]
|
||||
|
||||
#include <boost/type_traits/function_traits.hpp>
|
||||
|
||||
#define BOOST_IDENTITY_TYPE(parenthesized_type) \
|
||||
boost::function_traits<void parenthesized_type>::arg1_type
|
||||
|
||||
Essentially, the type is wrapped between round parenthesis `(std::map<int, char>)` so it can be passed as a single macro parameter even if it contains commas.
|
||||
Then the parenthesized type is transformed into the type of a function returning `void` and with the specified type as the type of the first and only argument `void (std::map<int, char>)`.
|
||||
Finally, the type of the first argument `arg1_type` is extracted at compile-time using the `function_traits` meta-function therefore obtaining the original type from the parenthesized type (effectively stripping the extra parenthesis from around the specified type).
|
||||
|
||||
[endsect]
|
||||
|
||||
[xinclude reference.xml]
|
||||
|
||||
@@ -1,15 +0,0 @@
|
||||
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
|
||||
<html>
|
||||
<head>
|
||||
<meta http-equiv="refresh" content="0; URL=doc/html/index.html">
|
||||
</head>
|
||||
<body>
|
||||
Automatic redirection failed, click this
|
||||
<a href="doc/html/index.html">link</a> <hr>
|
||||
<p><EFBFBD> Copyright Lorenzo Caminiti, 2009-2012</p>
|
||||
<p>Distributed under the Boost Software License, Version 1.0 (see
|
||||
accompanying file <a href="../../../LICENSE_1_0.txt">
|
||||
LICENSE_1_0.txt</a> or a copy at
|
||||
<a href="http://www.boost.org/LICENSE_1_0.txt">www.boost.org/LICENSE_1_0.txt</a>)</p>
|
||||
</body>
|
||||
</html>
|
||||
@@ -1,16 +0,0 @@
|
||||
|
||||
# Copyright (C) 2009-2012 Lorenzo Caminiti
|
||||
# Distributed under the Boost Software License, Version 1.0
|
||||
# (see accompanying file LICENSE_1_0.txt or a copy at
|
||||
# http://www.boost.org/LICENSE_1_0.txt)
|
||||
# Home at http://www.boost.org/libs/utility/identity_type
|
||||
|
||||
import testing ;
|
||||
|
||||
compile-fail var_error.cpp ;
|
||||
run var.cpp ;
|
||||
run template.cpp ;
|
||||
run abstract.cpp ;
|
||||
run noncopyable.cpp ;
|
||||
run paren.cpp ;
|
||||
|
||||
@@ -1,35 +0,0 @@
|
||||
|
||||
// Copyright (C) 2009-2012 Lorenzo Caminiti
|
||||
// Distributed under the Boost Software License, Version 1.0
|
||||
// (see accompanying file LICENSE_1_0.txt or a copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
// Home at http://www.boost.org/libs/utility/identity_type
|
||||
|
||||
#include <boost/utility/identity_type.hpp>
|
||||
#include <boost/static_assert.hpp>
|
||||
#include <boost/type_traits/add_reference.hpp>
|
||||
#include <boost/type_traits/remove_reference.hpp>
|
||||
|
||||
//[abstract
|
||||
#define TMP_ASSERT(metafunction) \
|
||||
BOOST_STATIC_ASSERT(metafunction::value)
|
||||
|
||||
template<typename T, bool b>
|
||||
struct abstract {
|
||||
static const bool value = b;
|
||||
virtual void f(T const& x) = 0; // Pure virtual function.
|
||||
};
|
||||
|
||||
TMP_ASSERT(
|
||||
boost::remove_reference< // Add and remove
|
||||
BOOST_IDENTITY_TYPE(( // reference for
|
||||
boost::add_reference< // abstract type.
|
||||
abstract<int, true>
|
||||
>::type
|
||||
))
|
||||
>::type
|
||||
);
|
||||
//]
|
||||
|
||||
int main() { return 0; }
|
||||
|
||||
@@ -1,25 +0,0 @@
|
||||
|
||||
// Copyright (C) 2009-2012 Lorenzo Caminiti
|
||||
// Distributed under the Boost Software License, Version 1.0
|
||||
// (see accompanying file LICENSE_1_0.txt or a copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
// Home at http://www.boost.org/libs/utility/identity_type
|
||||
|
||||
#include <boost/utility/identity_type.hpp>
|
||||
#include <boost/static_assert.hpp>
|
||||
#include <boost/noncopyable.hpp>
|
||||
|
||||
//[noncopyable
|
||||
#define TMP_ASSERT(metafunction) \
|
||||
BOOST_STATIC_ASSERT(metafunction::value)
|
||||
|
||||
template<typename T, T init>
|
||||
struct noncopyable : boost::noncopyable {
|
||||
static const T value = init;
|
||||
};
|
||||
|
||||
TMP_ASSERT(BOOST_IDENTITY_TYPE((noncopyable<bool, true>)));
|
||||
//]
|
||||
|
||||
int main() { return 0; }
|
||||
|
||||
@@ -1,35 +0,0 @@
|
||||
|
||||
// Copyright (C) 2009-2012 Lorenzo Caminiti
|
||||
// Distributed under the Boost Software License, Version 1.0
|
||||
// (see accompanying file LICENSE_1_0.txt or a copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
// Home at http://www.boost.org/libs/utility/identity_type
|
||||
|
||||
#include <boost/utility/identity_type.hpp>
|
||||
#include <boost/static_assert.hpp>
|
||||
#include <boost/type_traits/is_const.hpp>
|
||||
#include <map>
|
||||
|
||||
//[paren
|
||||
#define TMP_ASSERT_PAREN(parenthesized_metafunction) \
|
||||
/* use `BOOST_IDENTITY_TYPE` in macro definition instead of invocation */ \
|
||||
BOOST_STATIC_ASSERT(BOOST_IDENTITY_TYPE(parenthesized_metafunction)::value)
|
||||
|
||||
#define TMP_ASSERT(metafunction) \
|
||||
BOOST_STATIC_ASSERT(metafunction::value)
|
||||
|
||||
// Specify only extra parenthesis `((...))`.
|
||||
TMP_ASSERT_PAREN((boost::is_const<std::map<int, char> const>));
|
||||
|
||||
// Specify both the extra parenthesis `((...))` and `BOOST_IDENTITY_TYPE` macro.
|
||||
TMP_ASSERT(BOOST_IDENTITY_TYPE((boost::is_const<std::map<int, char> const>)));
|
||||
//]
|
||||
|
||||
//[paren_always
|
||||
TMP_ASSERT_PAREN((boost::is_const<int const>)); // Always extra `((...))`.
|
||||
|
||||
TMP_ASSERT(boost::is_const<int const>); // No extra `((...))` and no macro.
|
||||
//]
|
||||
|
||||
int main() { return 0; }
|
||||
|
||||
@@ -1,48 +0,0 @@
|
||||
|
||||
// Copyright (C) 2009-2012 Lorenzo Caminiti
|
||||
// Distributed under the Boost Software License, Version 1.0
|
||||
// (see accompanying file LICENSE_1_0.txt or a copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
// Home at http://www.boost.org/libs/utility/identity_type
|
||||
|
||||
#include <boost/utility/identity_type.hpp>
|
||||
#include <map>
|
||||
#include <iostream>
|
||||
|
||||
//[template_f_decl
|
||||
#define ARG(type, n) type arg ## n
|
||||
|
||||
template<typename T>
|
||||
void f( // Prefix macro with `typename` in templates.
|
||||
ARG(typename BOOST_IDENTITY_TYPE((std::map<int, T>)), 1)
|
||||
) {
|
||||
std::cout << arg1[0] << std::endl;
|
||||
}
|
||||
//]
|
||||
|
||||
//[template_g_decl
|
||||
template<typename T>
|
||||
void g(
|
||||
std::map<int, T> arg1
|
||||
) {
|
||||
std::cout << arg1[0] << std::endl;
|
||||
}
|
||||
//]
|
||||
|
||||
int main() {
|
||||
//[template_f_call
|
||||
std::map<int, char> a;
|
||||
a[0] = 'a';
|
||||
|
||||
f<char>(a); // OK...
|
||||
// f(a); // ... but error.
|
||||
//]
|
||||
|
||||
//[template_g_call
|
||||
g<char>(a); // OK...
|
||||
g(a); // ... and also OK.
|
||||
//]
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
@@ -1,26 +0,0 @@
|
||||
|
||||
// Copyright (C) 2009-2012 Lorenzo Caminiti
|
||||
// Distributed under the Boost Software License, Version 1.0
|
||||
// (see accompanying file LICENSE_1_0.txt or a copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
// Home at http://www.boost.org/libs/utility/identity_type
|
||||
|
||||
#include <map>
|
||||
|
||||
#define VAR(type, n) type var ## n
|
||||
|
||||
VAR(int, 1); // OK.
|
||||
|
||||
//[var_typedef
|
||||
typedef std::map<int, char> map_type;
|
||||
VAR(map_type, 3); // OK.
|
||||
//]
|
||||
|
||||
//[var_ok
|
||||
#include <boost/utility/identity_type.hpp>
|
||||
|
||||
VAR(BOOST_IDENTITY_TYPE((std::map<int, char>)), 4); // OK.
|
||||
//]
|
||||
|
||||
int main() { return 0; }
|
||||
|
||||
@@ -1,18 +0,0 @@
|
||||
|
||||
// Copyright (C) 2009-2012 Lorenzo Caminiti
|
||||
// Distributed under the Boost Software License, Version 1.0
|
||||
// (see accompanying file LICENSE_1_0.txt or a copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
// Home at http://www.boost.org/libs/utility/identity_type
|
||||
|
||||
#include <map>
|
||||
|
||||
//[var_error
|
||||
#define VAR(type, n) type var ## n
|
||||
|
||||
VAR(int, 1); // OK.
|
||||
VAR(std::map<int, char>, 2); // Error.
|
||||
//]
|
||||
|
||||
int main() { return 0; }
|
||||
|
||||
@@ -28,7 +28,7 @@ namespace detail
|
||||
inline void current_function_helper()
|
||||
{
|
||||
|
||||
#if defined(__GNUC__) || (defined(__MWERKS__) && (__MWERKS__ >= 0x3000)) || (defined(__ICC) && (__ICC >= 600)) || defined(__ghs__)
|
||||
#if defined(__GNUC__) || (defined(__MWERKS__) && (__MWERKS__ >= 0x3000)) || (defined(__ICC) && (__ICC >= 600))
|
||||
|
||||
# define BOOST_CURRENT_FUNCTION __PRETTY_FUNCTION__
|
||||
|
||||
@@ -65,4 +65,3 @@ inline void current_function_helper()
|
||||
} // namespace boost
|
||||
|
||||
#endif // #ifndef BOOST_CURRENT_FUNCTION_HPP_INCLUDED
|
||||
|
||||
|
||||
@@ -13,7 +13,6 @@
|
||||
#include <boost/utility/base_from_member.hpp>
|
||||
#include <boost/utility/binary.hpp>
|
||||
#include <boost/utility/enable_if.hpp>
|
||||
#include <boost/utility/identity_type.hpp>
|
||||
#include <boost/checked_delete.hpp>
|
||||
#include <boost/next_prior.hpp>
|
||||
#include <boost/noncopyable.hpp>
|
||||
|
||||
@@ -13,7 +13,6 @@
|
||||
//----------------------------------------------------------------------------//
|
||||
|
||||
#include <boost/type_traits/add_rvalue_reference.hpp>
|
||||
//#include <boost/type_traits/add_lvalue_reference.hpp>
|
||||
|
||||
//----------------------------------------------------------------------------//
|
||||
// //
|
||||
@@ -37,13 +36,9 @@
|
||||
|
||||
namespace boost {
|
||||
|
||||
//#if !defined(BOOST_NO_RVALUE_REFERENCES)
|
||||
template <typename T>
|
||||
typename add_rvalue_reference<T>::type declval() BOOST_NOEXCEPT; // as unevaluated operand
|
||||
//#else
|
||||
// template <typename T>
|
||||
// typename add_lvalue_reference<T>::type declval() BOOST_NOEXCEPT; // as unevaluated operand
|
||||
//#endif
|
||||
typename add_rvalue_reference<T>::type declval(); //noexcept; // as unevaluated operand
|
||||
|
||||
} // namespace boost
|
||||
|
||||
#endif // BOOST_TYPE_TRAITS_EXT_DECLVAL__HPP
|
||||
|
||||
@@ -1,46 +0,0 @@
|
||||
|
||||
// Copyright (C) 2009-2012 Lorenzo Caminiti
|
||||
// Distributed under the Boost Software License, Version 1.0
|
||||
// (see accompanying file LICENSE_1_0.txt or a copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
// Home at http://www.boost.org/libs/utility/identity_type
|
||||
|
||||
/** @file
|
||||
Wrap type expressions with round parenthesis so they can be passed to macros
|
||||
even if they contain commas.
|
||||
*/
|
||||
|
||||
#ifndef BOOST_IDENTITY_TYPE_HPP_
|
||||
#define BOOST_IDENTITY_TYPE_HPP_
|
||||
|
||||
#include <boost/type_traits/function_traits.hpp>
|
||||
|
||||
/**
|
||||
@brief This macro allows to wrap the specified type expression within extra
|
||||
round parenthesis so the type can be passed as a single macro parameter even if
|
||||
it contains commas (not already wrapped within round parenthesis).
|
||||
|
||||
@Params
|
||||
@Param{parenthesized_type,
|
||||
The type expression to be passed as macro parameter wrapped by a single set
|
||||
of round parenthesis <c>(...)</c>.
|
||||
This type expression can contain an arbitrary number of commas.
|
||||
}
|
||||
@EndParams
|
||||
|
||||
This macro works on any C++03 compiler (it does not use variadic macros).
|
||||
|
||||
This macro must be prefixed by <c>typename</c> when used within templates.
|
||||
Note that the compiler will not be able to automatically determine function
|
||||
template parameters when they are wrapped with this macro (these parameters
|
||||
need to be explicitly specified when calling the function template).
|
||||
|
||||
On some compilers (like GCC), using this macro on abstract types requires to
|
||||
add and remove a reference to the specified type.
|
||||
*/
|
||||
#define BOOST_IDENTITY_TYPE(parenthesized_type) \
|
||||
/* must NOT prefix this with `::` to work with parenthesized syntax */ \
|
||||
boost::function_traits< void parenthesized_type >::arg1_type
|
||||
|
||||
#endif // #include guard
|
||||
|
||||
14
index.html
14
index.html
@@ -14,21 +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="doc/html/declval.html">declval</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>© Copyright Beman Dawes, 2001</p>
|
||||
@@ -41,4 +48,3 @@
|
||||
<!--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>
|
||||
|
||||
|
||||
14
utility.htm
14
utility.htm
@@ -224,20 +224,6 @@ typedef boost::result_of<
|
||||
>::type type;</pre>
|
||||
</blockquote>
|
||||
|
||||
<p>In a future
|
||||
release, <code>BOOST_RESULT_OF_USE_DECLTYPE</code>
|
||||
may be enabled by default on compilers that
|
||||
support <code>decltype</code>, so if you use the above
|
||||
protocol please take care to ensure that
|
||||
the <code>result_type</code>
|
||||
and <code>result<></code> members accurately
|
||||
represent the result type. If you wish to continue to
|
||||
use the protocol on compilers that
|
||||
support <code>decltype</code>,
|
||||
use <code>boost::tr1_result_of</code>, which is also
|
||||
defined
|
||||
in <code><<a href="../../boost/utility/result_of.hpp">boost/utility/result_of.hpp</a>></code>.</p>
|
||||
|
||||
<a name="BOOST_NO_RESULT_OF"></a>
|
||||
<p>This implementation of <code>result_of</code>
|
||||
requires class template partial specialization, the
|
||||
|
||||
@@ -22,7 +22,7 @@
|
||||
#pragma hdrstop
|
||||
#endif
|
||||
|
||||
#include "boost/test/minimal.hpp"
|
||||
#include <boost/detail/lightweight_test.hpp>
|
||||
|
||||
//
|
||||
// Sample POD type
|
||||
@@ -215,7 +215,7 @@ template<class T>
|
||||
void check_initialized_value ( T const& y )
|
||||
{
|
||||
T initializedValue = boost::initialized_value ;
|
||||
BOOST_CHECK ( y == initializedValue ) ;
|
||||
BOOST_TEST ( y == initializedValue ) ;
|
||||
}
|
||||
|
||||
#ifdef __BORLANDC__
|
||||
@@ -245,128 +245,125 @@ void check_initialized_value( NonPOD const& )
|
||||
template<class T>
|
||||
bool test ( T const& y, T const& z )
|
||||
{
|
||||
const boost::unit_test::counter_t counter_before_test = boost::minimal_test::errors_counter();
|
||||
const int errors_before_test = boost::detail::test_errors();
|
||||
|
||||
check_initialized_value(y);
|
||||
|
||||
boost::value_initialized<T> x ;
|
||||
BOOST_CHECK ( y == x ) ;
|
||||
BOOST_CHECK ( y == boost::get(x) ) ;
|
||||
BOOST_TEST ( y == x ) ;
|
||||
BOOST_TEST ( y == boost::get(x) ) ;
|
||||
|
||||
static_cast<T&>(x) = z ;
|
||||
boost::get(x) = z ;
|
||||
BOOST_CHECK ( x == z ) ;
|
||||
BOOST_TEST ( x == z ) ;
|
||||
|
||||
boost::value_initialized<T> const x_c ;
|
||||
BOOST_CHECK ( y == x_c ) ;
|
||||
BOOST_CHECK ( y == boost::get(x_c) ) ;
|
||||
BOOST_TEST ( y == x_c ) ;
|
||||
BOOST_TEST ( y == boost::get(x_c) ) ;
|
||||
T& x_c_ref = const_cast<T&>( boost::get(x_c) ) ;
|
||||
x_c_ref = z ;
|
||||
BOOST_CHECK ( x_c == z ) ;
|
||||
BOOST_TEST ( x_c == z ) ;
|
||||
|
||||
boost::value_initialized<T> const copy1 = x;
|
||||
BOOST_CHECK ( boost::get(copy1) == boost::get(x) ) ;
|
||||
BOOST_TEST ( boost::get(copy1) == boost::get(x) ) ;
|
||||
|
||||
boost::value_initialized<T> copy2;
|
||||
copy2 = x;
|
||||
BOOST_CHECK ( boost::get(copy2) == boost::get(x) ) ;
|
||||
BOOST_TEST ( boost::get(copy2) == boost::get(x) ) ;
|
||||
|
||||
boost::shared_ptr<boost::value_initialized<T> > ptr( new boost::value_initialized<T> );
|
||||
BOOST_CHECK ( y == *ptr ) ;
|
||||
BOOST_TEST ( y == *ptr ) ;
|
||||
|
||||
#if !BOOST_WORKAROUND(BOOST_MSVC, < 1300)
|
||||
boost::value_initialized<T const> cx ;
|
||||
BOOST_CHECK ( y == cx ) ;
|
||||
BOOST_CHECK ( y == boost::get(cx) ) ;
|
||||
BOOST_TEST ( y == cx ) ;
|
||||
BOOST_TEST ( y == boost::get(cx) ) ;
|
||||
|
||||
boost::value_initialized<T const> const cx_c ;
|
||||
BOOST_CHECK ( y == cx_c ) ;
|
||||
BOOST_CHECK ( y == boost::get(cx_c) ) ;
|
||||
BOOST_TEST ( y == cx_c ) ;
|
||||
BOOST_TEST ( y == boost::get(cx_c) ) ;
|
||||
#endif
|
||||
|
||||
return boost::minimal_test::errors_counter() == counter_before_test ;
|
||||
return boost::detail::test_errors() == errors_before_test ;
|
||||
}
|
||||
|
||||
int test_main(int, char **)
|
||||
int main(int, char **)
|
||||
{
|
||||
BOOST_CHECK ( test( 0,1234 ) ) ;
|
||||
BOOST_CHECK ( test( 0.0,12.34 ) ) ;
|
||||
BOOST_CHECK ( test( POD(0,0,0.0), POD('a',1234,56.78f) ) ) ;
|
||||
BOOST_CHECK ( test( NonPOD( std::string() ), NonPOD( std::string("something") ) ) ) ;
|
||||
BOOST_TEST ( test( 0,1234 ) ) ;
|
||||
BOOST_TEST ( test( 0.0,12.34 ) ) ;
|
||||
BOOST_TEST ( test( POD(0,0,0.0), POD('a',1234,56.78f) ) ) ;
|
||||
BOOST_TEST ( test( NonPOD( std::string() ), NonPOD( std::string("something") ) ) ) ;
|
||||
|
||||
NonPOD NonPOD_object( std::string("NonPOD_object") );
|
||||
BOOST_CHECK ( test<NonPOD *>( 0, &NonPOD_object ) ) ;
|
||||
BOOST_TEST ( test<NonPOD *>( 0, &NonPOD_object ) ) ;
|
||||
|
||||
AggregatePODStruct zeroInitializedAggregatePODStruct = { 0.0f, '\0', 0 };
|
||||
AggregatePODStruct nonZeroInitializedAggregatePODStruct = { 1.25f, 'a', -1 };
|
||||
BOOST_CHECK ( test(zeroInitializedAggregatePODStruct, nonZeroInitializedAggregatePODStruct) );
|
||||
BOOST_TEST ( test(zeroInitializedAggregatePODStruct, nonZeroInitializedAggregatePODStruct) );
|
||||
|
||||
StringAndInt stringAndInt0;
|
||||
StringAndInt stringAndInt1;
|
||||
stringAndInt0.i = 0;
|
||||
stringAndInt1.i = 1;
|
||||
stringAndInt1.s = std::string("1");
|
||||
BOOST_CHECK ( test(stringAndInt0, stringAndInt1) );
|
||||
BOOST_TEST ( test(stringAndInt0, stringAndInt1) );
|
||||
|
||||
StructWithDestructor structWithDestructor0;
|
||||
StructWithDestructor structWithDestructor1;
|
||||
structWithDestructor0.i = 0;
|
||||
structWithDestructor1.i = 1;
|
||||
BOOST_CHECK ( test(structWithDestructor0, structWithDestructor1) );
|
||||
BOOST_TEST ( test(structWithDestructor0, structWithDestructor1) );
|
||||
|
||||
StructWithVirtualFunction structWithVirtualFunction0;
|
||||
StructWithVirtualFunction structWithVirtualFunction1;
|
||||
structWithVirtualFunction0.i = 0;
|
||||
structWithVirtualFunction1.i = 1;
|
||||
BOOST_CHECK ( test(structWithVirtualFunction0, structWithVirtualFunction1) );
|
||||
BOOST_TEST ( test(structWithVirtualFunction0, structWithVirtualFunction1) );
|
||||
|
||||
DerivedFromAggregatePODStruct derivedFromAggregatePODStruct0;
|
||||
DerivedFromAggregatePODStruct derivedFromAggregatePODStruct1;
|
||||
static_cast<AggregatePODStruct &>(derivedFromAggregatePODStruct0) = zeroInitializedAggregatePODStruct;
|
||||
static_cast<AggregatePODStruct &>(derivedFromAggregatePODStruct1) = nonZeroInitializedAggregatePODStruct;
|
||||
BOOST_CHECK ( test(derivedFromAggregatePODStruct0, derivedFromAggregatePODStruct1) );
|
||||
BOOST_TEST ( test(derivedFromAggregatePODStruct0, derivedFromAggregatePODStruct1) );
|
||||
|
||||
AggregatePODStructWrapper aggregatePODStructWrapper0;
|
||||
AggregatePODStructWrapper aggregatePODStructWrapper1;
|
||||
aggregatePODStructWrapper0.dataMember = zeroInitializedAggregatePODStruct;
|
||||
aggregatePODStructWrapper1.dataMember = nonZeroInitializedAggregatePODStruct;
|
||||
BOOST_CHECK ( test(aggregatePODStructWrapper0, aggregatePODStructWrapper1) );
|
||||
BOOST_TEST ( test(aggregatePODStructWrapper0, aggregatePODStructWrapper1) );
|
||||
|
||||
ArrayOfBytes zeroInitializedArrayOfBytes = { 0 };
|
||||
boost::value_initialized<ArrayOfBytes> valueInitializedArrayOfBytes;
|
||||
BOOST_CHECK (std::memcmp(get(valueInitializedArrayOfBytes), zeroInitializedArrayOfBytes, sizeof(ArrayOfBytes)) == 0);
|
||||
BOOST_TEST (std::memcmp(get(valueInitializedArrayOfBytes), zeroInitializedArrayOfBytes, sizeof(ArrayOfBytes)) == 0);
|
||||
|
||||
boost::value_initialized<ArrayOfBytes> valueInitializedArrayOfBytes2;
|
||||
valueInitializedArrayOfBytes2 = valueInitializedArrayOfBytes;
|
||||
BOOST_CHECK (std::memcmp(get(valueInitializedArrayOfBytes), get(valueInitializedArrayOfBytes2), sizeof(ArrayOfBytes)) == 0);
|
||||
BOOST_TEST (std::memcmp(get(valueInitializedArrayOfBytes), get(valueInitializedArrayOfBytes2), sizeof(ArrayOfBytes)) == 0);
|
||||
|
||||
boost::value_initialized<CopyFunctionCallTester> copyFunctionCallTester1;
|
||||
BOOST_CHECK ( ! get(copyFunctionCallTester1).is_copy_constructed);
|
||||
BOOST_CHECK ( ! get(copyFunctionCallTester1).is_assignment_called);
|
||||
BOOST_TEST ( ! get(copyFunctionCallTester1).is_copy_constructed);
|
||||
BOOST_TEST ( ! get(copyFunctionCallTester1).is_assignment_called);
|
||||
|
||||
boost::value_initialized<CopyFunctionCallTester> copyFunctionCallTester2 = boost::value_initialized<CopyFunctionCallTester>(copyFunctionCallTester1);
|
||||
BOOST_CHECK ( get(copyFunctionCallTester2).is_copy_constructed);
|
||||
BOOST_CHECK ( ! get(copyFunctionCallTester2).is_assignment_called);
|
||||
BOOST_TEST ( get(copyFunctionCallTester2).is_copy_constructed);
|
||||
BOOST_TEST ( ! get(copyFunctionCallTester2).is_assignment_called);
|
||||
|
||||
boost::value_initialized<CopyFunctionCallTester> copyFunctionCallTester3;
|
||||
copyFunctionCallTester3 = boost::value_initialized<CopyFunctionCallTester>(copyFunctionCallTester1);
|
||||
BOOST_CHECK ( ! get(copyFunctionCallTester3).is_copy_constructed);
|
||||
BOOST_CHECK ( get(copyFunctionCallTester3).is_assignment_called);
|
||||
BOOST_TEST ( ! get(copyFunctionCallTester3).is_copy_constructed);
|
||||
BOOST_TEST ( get(copyFunctionCallTester3).is_assignment_called);
|
||||
|
||||
boost::value_initialized<SwapFunctionCallTester> swapFunctionCallTester1;
|
||||
boost::value_initialized<SwapFunctionCallTester> swapFunctionCallTester2;
|
||||
get(swapFunctionCallTester1).data = 1;
|
||||
get(swapFunctionCallTester2).data = 2;
|
||||
boost::swap(swapFunctionCallTester1, swapFunctionCallTester2);
|
||||
BOOST_CHECK( get(swapFunctionCallTester1).data == 2 );
|
||||
BOOST_CHECK( get(swapFunctionCallTester2).data == 1 );
|
||||
BOOST_CHECK( get(swapFunctionCallTester1).is_custom_swap_called );
|
||||
BOOST_CHECK( get(swapFunctionCallTester2).is_custom_swap_called );
|
||||
BOOST_TEST( get(swapFunctionCallTester1).data == 2 );
|
||||
BOOST_TEST( get(swapFunctionCallTester2).data == 1 );
|
||||
BOOST_TEST( get(swapFunctionCallTester1).is_custom_swap_called );
|
||||
BOOST_TEST( get(swapFunctionCallTester2).is_custom_swap_called );
|
||||
|
||||
return 0;
|
||||
return boost::report_errors();
|
||||
}
|
||||
|
||||
|
||||
unsigned int expected_failures = 0;
|
||||
|
||||
|
||||
|
||||
Reference in New Issue
Block a user