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d809d4e832 |
@ -85,7 +85,7 @@
|
||||
<hr>
|
||||
|
||||
<p><a href="http://validator.w3.org/check?uri=referer"><img border="0" src=
|
||||
"http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01 Transitional"
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"../../doc/images/valid-html401.png" alt="Valid HTML 4.01 Transitional"
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height="31" width="88"></a></p>
|
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|
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<p>Revised
|
||||
|
@ -509,7 +509,7 @@ Returns the largest size that this Collection can ever have. <A href="#8">[8]</A
|
||||
<hr>
|
||||
|
||||
<p><a href="http://validator.w3.org/check?uri=referer"><img border="0" src=
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"http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01 Transitional"
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"../../doc/images/valid-html401.png" alt="Valid HTML 4.01 Transitional"
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height="31" width="88"></a></p>
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<p>Revised
|
||||
|
@ -160,7 +160,7 @@ t.~T()
|
||||
<hr>
|
||||
|
||||
<p><a href="http://validator.w3.org/check?uri=referer"><img border="0" src=
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"http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01 Transitional"
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"../../doc/images/valid-html401.png" alt="Valid HTML 4.01 Transitional"
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height="31" width="88"></a></p>
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|
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<p>Revised
|
||||
|
@ -185,7 +185,7 @@
|
||||
<hr>
|
||||
|
||||
<p><a href="http://validator.w3.org/check?uri=referer"><img border="0" src=
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"http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01 Transitional"
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"../../doc/images/valid-html401.png" alt="Valid HTML 4.01 Transitional"
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height="31" width="88"></a></p>
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<p>Revised
|
||||
|
@ -70,7 +70,7 @@
|
||||
<hr>
|
||||
|
||||
<p><a href="http://validator.w3.org/check?uri=referer"><img border="0" src=
|
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"http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01 Transitional"
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"../../doc/images/valid-html401.png" alt="Valid HTML 4.01 Transitional"
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height="31" width="88"></a></p>
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<p>Revised
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|
76
addressof_fn_test.cpp
Normal file
76
addressof_fn_test.cpp
Normal file
@ -0,0 +1,76 @@
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#include <boost/config.hpp>
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|
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#if defined(BOOST_MSVC)
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||||
#pragma warning(disable: 4786) // identifier truncated in debug info
|
||||
#pragma warning(disable: 4710) // function not inlined
|
||||
#pragma warning(disable: 4711) // function selected for automatic inline expansion
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#pragma warning(disable: 4514) // unreferenced inline removed
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#endif
|
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|
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// addressof_fn_test.cpp: addressof( f )
|
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//
|
||||
// Copyright (c) 2008, 2009 Peter Dimov
|
||||
//
|
||||
// Distributed under the Boost Software License, Version 1.0.
|
||||
// See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt
|
||||
|
||||
#include <boost/utility/addressof.hpp>
|
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#include <boost/detail/lightweight_test.hpp>
|
||||
|
||||
|
||||
void f0()
|
||||
{
|
||||
}
|
||||
|
||||
void f1(int)
|
||||
{
|
||||
}
|
||||
|
||||
void f2(int, int)
|
||||
{
|
||||
}
|
||||
|
||||
void f3(int, int, int)
|
||||
{
|
||||
}
|
||||
|
||||
void f4(int, int, int, int)
|
||||
{
|
||||
}
|
||||
|
||||
void f5(int, int, int, int, int)
|
||||
{
|
||||
}
|
||||
|
||||
void f6(int, int, int, int, int, int)
|
||||
{
|
||||
}
|
||||
|
||||
void f7(int, int, int, int, int, int, int)
|
||||
{
|
||||
}
|
||||
|
||||
void f8(int, int, int, int, int, int, int, int)
|
||||
{
|
||||
}
|
||||
|
||||
void f9(int, int, int, int, int, int, int, int, int)
|
||||
{
|
||||
}
|
||||
|
||||
int main()
|
||||
{
|
||||
BOOST_TEST( boost::addressof( f0 ) == &f0 );
|
||||
BOOST_TEST( boost::addressof( f1 ) == &f1 );
|
||||
BOOST_TEST( boost::addressof( f2 ) == &f2 );
|
||||
BOOST_TEST( boost::addressof( f3 ) == &f3 );
|
||||
BOOST_TEST( boost::addressof( f4 ) == &f4 );
|
||||
BOOST_TEST( boost::addressof( f5 ) == &f5 );
|
||||
BOOST_TEST( boost::addressof( f6 ) == &f6 );
|
||||
BOOST_TEST( boost::addressof( f7 ) == &f7 );
|
||||
BOOST_TEST( boost::addressof( f8 ) == &f8 );
|
||||
BOOST_TEST( boost::addressof( f9 ) == &f9 );
|
||||
|
||||
return boost::report_errors();
|
||||
}
|
95
addressof_test2.cpp
Normal file
95
addressof_test2.cpp
Normal file
@ -0,0 +1,95 @@
|
||||
// Copyright (C) 2002 Brad King (brad.king@kitware.com)
|
||||
// Douglas Gregor (gregod@cs.rpi.edu)
|
||||
//
|
||||
// Copyright 2009 Peter Dimov
|
||||
//
|
||||
// Distributed under the Boost Software License, Version 1.0. (See
|
||||
// accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
// For more information, see http://www.boost.org
|
||||
|
||||
|
||||
#include <boost/utility/addressof.hpp>
|
||||
|
||||
#if defined(BOOST_MSVC) && (BOOST_MSVC < 1300)
|
||||
#pragma warning(push, 3)
|
||||
#endif
|
||||
|
||||
#include <iostream>
|
||||
|
||||
#if defined(BOOST_MSVC) && (BOOST_MSVC < 1300)
|
||||
#pragma warning(pop)
|
||||
#endif
|
||||
|
||||
#include <boost/detail/lightweight_test.hpp>
|
||||
|
||||
template<class T> void scalar_test( T * = 0 )
|
||||
{
|
||||
T* px = new T();
|
||||
|
||||
T& x = *px;
|
||||
BOOST_TEST( boost::addressof(x) == px );
|
||||
|
||||
const T& cx = *px;
|
||||
const T* pcx = boost::addressof(cx);
|
||||
BOOST_TEST( pcx == px );
|
||||
|
||||
volatile T& vx = *px;
|
||||
volatile T* pvx = boost::addressof(vx);
|
||||
BOOST_TEST( pvx == px );
|
||||
|
||||
const volatile T& cvx = *px;
|
||||
const volatile T* pcvx = boost::addressof(cvx);
|
||||
BOOST_TEST( pcvx == px );
|
||||
|
||||
delete px;
|
||||
}
|
||||
|
||||
template<class T> void array_test( T * = 0 )
|
||||
{
|
||||
T nrg[3] = {1,2,3};
|
||||
T (*pnrg)[3] = &nrg;
|
||||
BOOST_TEST( boost::addressof(nrg) == pnrg );
|
||||
|
||||
T const cnrg[3] = {1,2,3};
|
||||
T const (*pcnrg)[3] = &cnrg;
|
||||
BOOST_TEST( boost::addressof(cnrg) == pcnrg );
|
||||
}
|
||||
|
||||
class convertible {
|
||||
public:
|
||||
|
||||
convertible( int = 0 )
|
||||
{
|
||||
}
|
||||
|
||||
template<class U> operator U () const
|
||||
{
|
||||
return U();
|
||||
}
|
||||
};
|
||||
|
||||
class convertible2 {
|
||||
public:
|
||||
|
||||
convertible2( int = 0 )
|
||||
{
|
||||
}
|
||||
|
||||
operator convertible2* () const
|
||||
{
|
||||
return 0;
|
||||
}
|
||||
};
|
||||
|
||||
int main()
|
||||
{
|
||||
scalar_test<convertible>();
|
||||
scalar_test<convertible2>();
|
||||
|
||||
array_test<convertible>();
|
||||
array_test<convertible2>();
|
||||
|
||||
return boost::report_errors();
|
||||
}
|
@ -146,7 +146,7 @@ int main()
|
||||
<hr>
|
||||
|
||||
<p><a href="http://validator.w3.org/check?uri=referer"><img border="0" src=
|
||||
"http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01 Transitional"
|
||||
"../../doc/images/valid-html401.png" alt="Valid HTML 4.01 Transitional"
|
||||
height="31" width="88"></a></p>
|
||||
|
||||
<p>Revised
|
||||
|
@ -99,7 +99,7 @@ directly to the container:</p>
|
||||
<H2><A NAME="framework"></A>Framework</H2>
|
||||
<p>
|
||||
This library proposes a framework to allow some containers to directly contruct contained objects in-place without requiring
|
||||
the entire set of constructor overloads ftom the contained type. It also allows the container to remove the CopyConstuctible
|
||||
the entire set of constructor overloads from the contained type. It also allows the container to remove the CopyConstuctible
|
||||
requirement from the contained type since objects can be directly constructed in-place without need of a copy.<br>
|
||||
The only requirement on the container is that it must provide proper storage (that is, correctly aligned and sized).
|
||||
Naturally, the container will typically support uninitialized storage to avoid the in-place construction to override
|
||||
@ -117,7 +117,7 @@ The following simplified example shows the basic idea. A complete example follow
|
||||
<pre>struct C
|
||||
{
|
||||
template<class InPlaceFactory>
|
||||
C ( InPlaceFactory const& aFactoty )
|
||||
C ( InPlaceFactory const& aFactory )
|
||||
:
|
||||
contained_ ( uninitialized_storage() )
|
||||
{
|
||||
@ -293,4 +293,4 @@ the latest version of this file can be found at <A
|
||||
HREF="http://www.boost.org">www.boost.org</A>, and the boost
|
||||
<A HREF="http://www.boost.org/more/mailing_lists.htm#main">discussion lists</A></P>
|
||||
</BODY>
|
||||
</HTML>
|
||||
</HTML>
|
||||
|
@ -6,12 +6,8 @@
|
||||
#ifndef UUID_1D94A7C6054E11DB9804B622A1EF5492
|
||||
#define UUID_1D94A7C6054E11DB9804B622A1EF5492
|
||||
|
||||
#include <boost/exception/diagnostic_information.hpp>
|
||||
#include <boost/exception/error_info.hpp>
|
||||
#include <boost/exception/exception.hpp>
|
||||
#include <boost/exception/get_error_info.hpp>
|
||||
#include <boost/exception/info.hpp>
|
||||
#include <boost/exception/info_tuple.hpp>
|
||||
#include <boost/exception_ptr.hpp>
|
||||
//The header <boost/exception.hpp> has been deprecated.
|
||||
//Please #include <boost/exception/all.hpp> instead.
|
||||
#include <boost/exception/all.hpp>
|
||||
|
||||
#endif
|
||||
|
@ -179,6 +179,11 @@ unwrap_ref(T& t)
|
||||
return t;
|
||||
}
|
||||
|
||||
template<class T> inline T* get_pointer( reference_wrapper<T> const & r )
|
||||
{
|
||||
return r.get_pointer();
|
||||
}
|
||||
|
||||
} // namespace boost
|
||||
|
||||
#endif // #ifndef BOOST_REF_HPP_INCLUDED
|
||||
|
@ -7,6 +7,6 @@
|
||||
#ifndef BOOST_SWAP_HPP
|
||||
#define BOOST_SWAP_HPP
|
||||
|
||||
#include "./utility/swap.hpp"
|
||||
#include "boost/utility/swap.hpp"
|
||||
|
||||
#endif
|
||||
|
@ -21,6 +21,17 @@ namespace boost
|
||||
namespace detail
|
||||
{
|
||||
|
||||
template<class T> struct addr_impl_ref
|
||||
{
|
||||
T & v_;
|
||||
|
||||
inline addr_impl_ref( T & v ): v_( v ) {}
|
||||
inline operator T& () const { return v_; }
|
||||
|
||||
private:
|
||||
addr_impl_ref & operator=(const addr_impl_ref &);
|
||||
};
|
||||
|
||||
template<class T> struct addressof_impl
|
||||
{
|
||||
static inline T * f( T & v, long )
|
||||
@ -39,12 +50,40 @@ template<class T> struct addressof_impl
|
||||
|
||||
template<class T> T * addressof( T & v )
|
||||
{
|
||||
#if defined( __BORLANDC__ ) && BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT( 0x610 ) )
|
||||
|
||||
return boost::detail::addressof_impl<T>::f( v, 0 );
|
||||
|
||||
#else
|
||||
|
||||
return boost::detail::addressof_impl<T>::f( boost::detail::addr_impl_ref<T>( v ), 0 );
|
||||
|
||||
#endif
|
||||
}
|
||||
|
||||
#if defined( __SUNPRO_CC ) && BOOST_WORKAROUND( __SUNPRO_CC, BOOST_TESTED_AT( 0x590 ) )
|
||||
|
||||
namespace detail
|
||||
{
|
||||
|
||||
template<class T> struct addressof_addp
|
||||
{
|
||||
typedef T * type;
|
||||
};
|
||||
|
||||
} // namespace detail
|
||||
|
||||
template< class T, std::size_t N >
|
||||
typename detail::addressof_addp< T[N] >::type addressof( T (&t)[N] )
|
||||
{
|
||||
return &t;
|
||||
}
|
||||
|
||||
#endif
|
||||
|
||||
// Borland doesn't like casting an array reference to a char reference
|
||||
// but these overloads work around the problem.
|
||||
# if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))
|
||||
#if defined( __BORLANDC__ ) && BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))
|
||||
template<typename T,std::size_t N>
|
||||
T (*addressof(T (&t)[N]))[N]
|
||||
{
|
||||
@ -56,7 +95,7 @@ const T (*addressof(const T (&t)[N]))[N]
|
||||
{
|
||||
return reinterpret_cast<const T(*)[N]>(&t);
|
||||
}
|
||||
# endif
|
||||
#endif
|
||||
|
||||
} // namespace boost
|
||||
|
||||
|
@ -10,47 +10,6 @@
|
||||
# error Boost result_of - do not include this file!
|
||||
#endif
|
||||
|
||||
#if defined(BOOST_HAS_DECLTYPE)
|
||||
|
||||
// As of N2588, C++0x result_of only supports function call
|
||||
// expressions of the form f(x). This precludes support for member
|
||||
// function pointers, which are invoked with expressions of the form
|
||||
// o->*f(x). This implementation supports both.
|
||||
template<typename F BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
|
||||
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
|
||||
struct result_of<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T))>
|
||||
: mpl::if_<
|
||||
mpl::or_< is_pointer<F>, is_member_function_pointer<F> >
|
||||
, detail::result_of_impl<
|
||||
typename remove_cv<F>::type,
|
||||
typename remove_cv<F>::type(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T)), false
|
||||
>
|
||||
, detail::result_of_decltype_impl<
|
||||
F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T))
|
||||
>
|
||||
>::type
|
||||
{};
|
||||
|
||||
namespace detail {
|
||||
|
||||
# define BOOST_RESULT_OF_STATIC_MEMBERS(z, n, _) \
|
||||
static T ## n t ## n; \
|
||||
/**/
|
||||
|
||||
template<typename F BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
|
||||
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
|
||||
class result_of_decltype_impl<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T))>
|
||||
{
|
||||
static F f;
|
||||
BOOST_PP_REPEAT(BOOST_PP_ITERATION(), BOOST_RESULT_OF_STATIC_MEMBERS, _)
|
||||
public:
|
||||
typedef decltype(f(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),t))) type;
|
||||
};
|
||||
|
||||
} // namespace detail
|
||||
|
||||
#else // defined(BOOST_HAS_DECLTYPE)
|
||||
|
||||
// CWPro8 requires an argument in a function type specialization
|
||||
#if BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3002)) && BOOST_PP_ITERATION() == 0
|
||||
# define BOOST_RESULT_OF_ARGS void
|
||||
@ -62,22 +21,11 @@ public:
|
||||
template<typename F BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
|
||||
BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
|
||||
struct result_of<F(BOOST_RESULT_OF_ARGS)>
|
||||
: mpl::if_<
|
||||
mpl::or_< is_pointer<F>, is_member_function_pointer<F> >
|
||||
, boost::detail::result_of_impl<
|
||||
typename remove_cv<F>::type,
|
||||
typename remove_cv<F>::type(BOOST_RESULT_OF_ARGS),
|
||||
(boost::detail::has_result_type<F>::value)>
|
||||
, boost::detail::result_of_impl<
|
||||
F,
|
||||
F(BOOST_RESULT_OF_ARGS),
|
||||
(boost::detail::has_result_type<F>::value)> >::type { };
|
||||
: boost::detail::result_of_impl<F, F(BOOST_RESULT_OF_ARGS), (boost::detail::has_result_type<F>::value)> {};
|
||||
#endif
|
||||
|
||||
#undef BOOST_RESULT_OF_ARGS
|
||||
|
||||
#endif // defined(BOOST_HAS_DECLTYPE)
|
||||
|
||||
#if BOOST_PP_ITERATION() >= 1
|
||||
|
||||
namespace detail {
|
||||
|
@ -10,18 +10,13 @@
|
||||
#define BOOST_RESULT_OF_HPP
|
||||
|
||||
#include <boost/config.hpp>
|
||||
#include <boost/preprocessor/iteration/iterate.hpp>
|
||||
#include <boost/preprocessor/punctuation/comma_if.hpp>
|
||||
#include <boost/preprocessor/repetition/enum_params.hpp>
|
||||
#include <boost/preprocessor/repetition/enum_shifted_params.hpp>
|
||||
#include <boost/type_traits/ice.hpp>
|
||||
#include <boost/type.hpp>
|
||||
#include <boost/preprocessor.hpp>
|
||||
#include <boost/detail/workaround.hpp>
|
||||
#include <boost/mpl/has_xxx.hpp>
|
||||
#include <boost/mpl/if.hpp>
|
||||
#include <boost/mpl/bool.hpp>
|
||||
#include <boost/mpl/or.hpp>
|
||||
#include <boost/type_traits/is_pointer.hpp>
|
||||
#include <boost/type_traits/is_member_function_pointer.hpp>
|
||||
#include <boost/type_traits/remove_cv.hpp>
|
||||
|
||||
#ifndef BOOST_RESULT_OF_NUM_ARGS
|
||||
# define BOOST_RESULT_OF_NUM_ARGS 10
|
||||
@ -37,7 +32,6 @@ namespace detail {
|
||||
BOOST_MPL_HAS_XXX_TRAIT_DEF(result_type)
|
||||
|
||||
template<typename F, typename FArgs, bool HasResultType> struct result_of_impl;
|
||||
template<typename F> struct result_of_decltype_impl;
|
||||
|
||||
template<typename F>
|
||||
struct result_of_void_impl
|
||||
@ -57,11 +51,6 @@ struct result_of_void_impl<R (&)(void)>
|
||||
typedef R type;
|
||||
};
|
||||
|
||||
// Determine the return type of a function pointer or pointer to member.
|
||||
template<typename F, typename FArgs>
|
||||
struct result_of_pointer
|
||||
: result_of_impl<typename remove_cv<F>::type, FArgs, false> { };
|
||||
|
||||
template<typename F, typename FArgs>
|
||||
struct result_of_impl<F, FArgs, true>
|
||||
{
|
||||
@ -81,8 +70,8 @@ struct result_of_nested_result : F::template result<FArgs>
|
||||
template<typename F, typename FArgs>
|
||||
struct result_of_impl<F, FArgs, false>
|
||||
: mpl::if_<is_function_with_no_args<FArgs>,
|
||||
result_of_void_impl<F>,
|
||||
result_of_nested_result<F, FArgs> >::type
|
||||
result_of_void_impl<F>,
|
||||
result_of_nested_result<F, FArgs> >::type
|
||||
{};
|
||||
|
||||
} // end namespace detail
|
||||
|
@ -8,6 +8,7 @@
|
||||
// 24 Dec 2007 (Refactored and worked around various compiler bugs) Fernando Cacciola, Niels Dekker
|
||||
// 23 May 2008 (Fixed operator= const issue, added initialized_value) Niels Dekker, Fernando Cacciola
|
||||
// 21 Ago 2008 (Added swap) Niels Dekker, Fernando Cacciola
|
||||
// 20 Feb 2009 (Fixed logical const-ness issues) Niels Dekker, Fernando Cacciola
|
||||
//
|
||||
#ifndef BOOST_UTILITY_VALUE_INIT_21AGO2002_HPP
|
||||
#define BOOST_UTILITY_VALUE_INIT_21AGO2002_HPP
|
||||
@ -90,7 +91,12 @@ class value_initialized
|
||||
wrapper_address()->wrapper::~wrapper();
|
||||
}
|
||||
|
||||
T& data() const
|
||||
T const & data() const
|
||||
{
|
||||
return wrapper_address()->data;
|
||||
}
|
||||
|
||||
T& data()
|
||||
{
|
||||
return wrapper_address()->data;
|
||||
}
|
||||
@ -100,12 +106,16 @@ class value_initialized
|
||||
::boost::swap( this->data(), arg.data() );
|
||||
}
|
||||
|
||||
operator T&() const { return this->data(); }
|
||||
operator T const &() const { return this->data(); }
|
||||
|
||||
operator T&() { return this->data(); }
|
||||
|
||||
} ;
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
template<class T>
|
||||
T const& get ( value_initialized<T> const& x )
|
||||
{
|
||||
|
@ -132,18 +132,18 @@
|
||||
class MyInt
|
||||
: boost::operators<MyInt>
|
||||
{
|
||||
bool operator<(const MyInt& x) const;
|
||||
bool operator<(const MyInt& x) const;
|
||||
bool operator==(const MyInt& x) const;
|
||||
MyInt& operator+=(const MyInt& x);
|
||||
MyInt& operator-=(const MyInt& x);
|
||||
MyInt& operator*=(const MyInt& x);
|
||||
MyInt& operator/=(const MyInt& x);
|
||||
MyInt& operator%=(const MyInt& x);
|
||||
MyInt& operator|=(const MyInt& x);
|
||||
MyInt& operator&=(const MyInt& x);
|
||||
MyInt& operator^=(const MyInt& x);
|
||||
MyInt& operator++();
|
||||
MyInt& operator--();
|
||||
MyInt& operator+=(const MyInt& x);
|
||||
MyInt& operator-=(const MyInt& x);
|
||||
MyInt& operator*=(const MyInt& x);
|
||||
MyInt& operator/=(const MyInt& x);
|
||||
MyInt& operator%=(const MyInt& x);
|
||||
MyInt& operator|=(const MyInt& x);
|
||||
MyInt& operator&=(const MyInt& x);
|
||||
MyInt& operator^=(const MyInt& x);
|
||||
MyInt& operator++();
|
||||
MyInt& operator--();
|
||||
};
|
||||
</pre>
|
||||
</blockquote>
|
||||
@ -345,7 +345,7 @@ class MyInt
|
||||
</ul>
|
||||
|
||||
<p>As Daniel Krügler pointed out, this technique violates 14.6.5/2
|
||||
and is thus non-portable. The reasoning is, that the operators injected
|
||||
and is thus non-portable. The reasoning is, that the operators injected
|
||||
by the instantiation of e.g.
|
||||
<code>less_than_comparable<myclass></code> can not be found
|
||||
by ADL according to the rules given by 3.4.2/2, since myclass is
|
||||
@ -445,6 +445,9 @@ const point<float> pi_over_4_normalized = pi_over_4 / length(pi_over_4);
|
||||
optional template parameter <code>B</code>, which is not shown, for the
|
||||
<a href="#chaining">base class chaining</a> technique.</p>
|
||||
|
||||
<p>The primary operand type <code>T</code> needs to be of class type,
|
||||
built-in types are not supported.</p>
|
||||
|
||||
<table cellpadding="5" border="1" align="center">
|
||||
<caption>
|
||||
Simple Arithmetic Operator Template Classes
|
||||
@ -917,7 +920,7 @@ T operator+( const T& lhs, const T& rhs )
|
||||
created, <code>operator+=</code> is called on it and it is copied to the
|
||||
function return value (which is another unnamed object of type
|
||||
<code>T</code>). The standard doesn't generally allow the intermediate
|
||||
object to be optimized away:
|
||||
object to be optimized away:
|
||||
|
||||
<blockquote>
|
||||
3.7.2/2: Automatic storage duration<br>
|
||||
@ -928,7 +931,7 @@ T operator+( const T& lhs, const T& rhs )
|
||||
unused, except that a class object or its copy may be eliminated as
|
||||
specified in 12.8.
|
||||
</blockquote>
|
||||
The reference to 12.8 is important for us:
|
||||
The reference to 12.8 is important for us:
|
||||
|
||||
<blockquote>
|
||||
12.8/15: Copying class objects<br>
|
||||
@ -942,7 +945,7 @@ T operator+( const T& lhs, const T& rhs )
|
||||
</blockquote>
|
||||
This optimization is known as the named return value optimization (NRVO),
|
||||
which leads us to the following implementation for
|
||||
<code>operator+</code>:
|
||||
<code>operator+</code>:
|
||||
<pre>
|
||||
T operator+( const T& lhs, const T& rhs )
|
||||
{
|
||||
@ -956,7 +959,7 @@ T operator+( const T& lhs, const T& rhs )
|
||||
even implement it in an incorrect way which makes it useless here.
|
||||
Without the NRVO, the NRVO-friendly code is no worse than the original
|
||||
code showed above, but there is another possible implementation, which
|
||||
has some very special properties:
|
||||
has some very special properties:
|
||||
<pre>
|
||||
T operator+( T lhs, const T& rhs )
|
||||
{
|
||||
@ -982,7 +985,7 @@ T operator+( T lhs, const T& rhs )
|
||||
will force the NRVO-friendly implementation to be used even for compilers
|
||||
that don't implement the NRVO. <br>
|
||||
<br>
|
||||
|
||||
|
||||
<h3><a name="grpd_oprs">Grouped Arithmetic Operators</a></h3>
|
||||
|
||||
<p>The following templates provide common groups of related operations.
|
||||
@ -1864,7 +1867,7 @@ T operator+( T lhs, const T& rhs )
|
||||
V, D, P, R></a></code></td>
|
||||
|
||||
<td>
|
||||
Supports the operations and has the requirements of
|
||||
Supports the operations and has the requirements of
|
||||
|
||||
<ul>
|
||||
<li><code><a href="#input_iteratable">input_iteratable<T,
|
||||
@ -1878,7 +1881,7 @@ T operator+( T lhs, const T& rhs )
|
||||
"output_iterator_helper">output_iterator_helper<T></a></code></td>
|
||||
|
||||
<td>
|
||||
Supports the operations and has the requirements of
|
||||
Supports the operations and has the requirements of
|
||||
|
||||
<ul>
|
||||
<li><code><a href=
|
||||
@ -1894,7 +1897,7 @@ T operator+( T lhs, const T& rhs )
|
||||
R></a></code></td>
|
||||
|
||||
<td>
|
||||
Supports the operations and has the requirements of
|
||||
Supports the operations and has the requirements of
|
||||
|
||||
<ul>
|
||||
<li><code><a href="#forward_iteratable">forward_iteratable<T,
|
||||
@ -1909,7 +1912,7 @@ T operator+( T lhs, const T& rhs )
|
||||
V, D, P, R></a></code></td>
|
||||
|
||||
<td>
|
||||
Supports the operations and has the requirements of
|
||||
Supports the operations and has the requirements of
|
||||
|
||||
<ul>
|
||||
<li><code><a href=
|
||||
@ -1925,7 +1928,7 @@ T operator+( T lhs, const T& rhs )
|
||||
V, D, P, R></a></code></td>
|
||||
|
||||
<td>
|
||||
Supports the operations and has the requirements of
|
||||
Supports the operations and has the requirements of
|
||||
|
||||
<ul>
|
||||
<li><code><a href=
|
||||
@ -1976,8 +1979,8 @@ struct function_output_iterator
|
||||
template<typename T>
|
||||
function_output_iterator& operator=(T const& value)
|
||||
{
|
||||
this->func(value);
|
||||
return *this;
|
||||
this->func(value);
|
||||
return *this;
|
||||
}
|
||||
|
||||
private:
|
||||
@ -2030,7 +2033,7 @@ public:
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<p>Check the <a href="../../status/compiler_status.html">compiler status
|
||||
<p>Check the <a href="http://www.boost.org/development/testing.html">compiler status
|
||||
report</a> for the test results with selected platforms.</p>
|
||||
<hr>
|
||||
|
||||
@ -2130,8 +2133,8 @@ public:
|
||||
<p>Revised: 7 Aug 2008</p>
|
||||
|
||||
<p>Copyright © Beman Dawes, David Abrahams, 1999-2001.</p>
|
||||
<p>Copyright © Daniel Frey, 2002-2008.</p>
|
||||
<p>Use, modification, and distribution is subject to the Boost Software
|
||||
<p>Copyright © Daniel Frey, 2002-2009.</p>
|
||||
<p>Use, modification, and distribution is subject to the Boost Software
|
||||
License, Version 1.0. (See accompanying file
|
||||
<a href="../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or copy at
|
||||
<a href="http://www.boost.org/LICENSE_1_0.txt">
|
||||
|
43
ref_test.cpp
43
ref_test.cpp
@ -68,54 +68,11 @@ struct ref_wrapper
|
||||
}
|
||||
};
|
||||
|
||||
struct copy_counter {
|
||||
static int count_;
|
||||
copy_counter(copy_counter const& other) {
|
||||
++count_;
|
||||
}
|
||||
copy_counter() {}
|
||||
static void reset() { count_ = 0; }
|
||||
static int count() { return copy_counter::count_; }
|
||||
};
|
||||
|
||||
int copy_counter::count_ = 0;
|
||||
|
||||
} // namespace unnamed
|
||||
|
||||
template <class T>
|
||||
void do_unwrap(T t) {
|
||||
|
||||
/* typename unwrap_reference<T>::type& lt = */
|
||||
unwrap_ref(t);
|
||||
|
||||
}
|
||||
|
||||
void unwrap_test() {
|
||||
|
||||
int i = 3;
|
||||
const int ci = 2;
|
||||
|
||||
do_unwrap(i);
|
||||
do_unwrap(ci);
|
||||
do_unwrap(ref(i));
|
||||
do_unwrap(cref(ci));
|
||||
do_unwrap(ref(ci));
|
||||
|
||||
copy_counter cc;
|
||||
BOOST_CHECK(cc.count() == 0);
|
||||
|
||||
do_unwrap(cc);
|
||||
do_unwrap(ref(cc));
|
||||
do_unwrap(cref(cc));
|
||||
|
||||
BOOST_CHECK(cc.count() == 1);
|
||||
BOOST_CHECK(unwrap_ref(ref(cc)).count() == 1);
|
||||
}
|
||||
|
||||
int test_main(int, char * [])
|
||||
{
|
||||
ref_wrapper<int>::test(1);
|
||||
ref_wrapper<int const>::test(1);
|
||||
unwrap_test();
|
||||
return 0;
|
||||
}
|
||||
|
22
swap.html
22
swap.html
@ -7,14 +7,18 @@
|
||||
</head>
|
||||
<body>
|
||||
<!-- Page header -->
|
||||
<h2>
|
||||
<img src="../../boost.png" alt="C++ Boost" align="middle" width="277" height="86"/>
|
||||
Header <<a href="../../boost/swap.hpp">boost/swap.hpp</a>>
|
||||
</h2>
|
||||
|
||||
<h1>Swap</h1>
|
||||
|
||||
<p>
|
||||
<tt>template<class T> void swap(T& <em>left</em>, T& <em>right</em>);</tt>
|
||||
</p>
|
||||
|
||||
<!-- Intoduction -->
|
||||
<!-- Introduction -->
|
||||
<p>
|
||||
The template function <tt>boost::swap</tt> allows the values of two variables to be swapped, using argument dependent lookup to select a specialized swap function if available. If no specialized swap function is available, <tt>std::swap</tt> is used.
|
||||
</p>
|
||||
@ -24,10 +28,10 @@
|
||||
<p>
|
||||
The generic <tt>std::swap</tt> function requires that the elements to be swapped are assignable and copy constructible. It is usually implemented using one copy construction and two assignments - this is often both unnecessarily restrictive and unnecessarily slow. In addition, where the generic swap implementation provides only the basic guarantee, specialized swap functions are often able to provide the no-throw exception guarantee (and it is considered best practice to do so where possible<sup><a href="#ref1">1</a></sup>).</p>
|
||||
<p>
|
||||
The alternative to using argument dependent lookup in this situation is to provide a template specialization of std::swap for every type that requires a specialized swap. Although this is legal C++, no Boost libraries use this method, whereas many Boost libraries provide specialized swap functions in their own namespaces.
|
||||
The alternative to using argument dependent lookup in this situation is to provide a template specialization of <tt>std::swap</tt> for every type that requires a specialized swap. Although this is legal C++, no Boost libraries use this method, whereas many Boost libraries provide specialized swap functions in their own namespaces.
|
||||
</p>
|
||||
<p>
|
||||
<tt>boost::swap</tt> also supports swapping built-in arrays. Note that <tt>std::swap</tt> doesn't yet do so, but a request to add an overload of <tt>std::swap</tt> for built-in arrays has been well-received by the Library Working Group of the C++ Standards Committee<sup><a href="#ref2">2</a></sup>.
|
||||
<tt>boost::swap</tt> also supports swapping built-in arrays. Note that <tt>std::swap</tt> originally did not do so, but a request to add an overload of <tt>std::swap</tt> for built-in arrays has been accepted by the C++ Standards Committee<sup><a href="#ref2">2</a></sup>.
|
||||
</p>
|
||||
|
||||
<!-- Exception Safety -->
|
||||
@ -45,11 +49,11 @@
|
||||
</ul>
|
||||
<p>Or:</p>
|
||||
<ul>
|
||||
<li>A function with the signature <tt>swap(T&,T&)</tt> is available via argument dependent lookup</li>
|
||||
<li>A function with the signature <tt>swap(T&,T&)</tt> is available via argument dependent lookup</li>
|
||||
</ul>
|
||||
<p>Or:</p>
|
||||
<ul>
|
||||
<li>A template specialization of std::swap exists for T</li>
|
||||
<li>A template specialization of <tt>std::swap</tt> exists for T</li>
|
||||
</ul>
|
||||
<p>Or:</p>
|
||||
<ul>
|
||||
@ -73,20 +77,20 @@
|
||||
<em><a href="mailto:Joseph.Gauterin@googlemail.com">Joseph Gauterin</a></em> - for the initial idea, implementation, tests, and documentation
|
||||
</li>
|
||||
<li>
|
||||
<em>Steven Wanatabe</em> - for the idea to make boost::swap less specialized than std::swap, thereby allowing the function to have the name 'swap' without introducing ambiguity
|
||||
<em>Steven Watanabe</em> - for the idea to make <tt>boost::swap</tt> less specialized than <tt>std::swap</tt>, thereby allowing the function to have the name 'swap' without introducing ambiguity
|
||||
</li>
|
||||
</ul>
|
||||
|
||||
<!-- References -->
|
||||
<hr/>
|
||||
<p><sup><a id="ref1"/>[1]</sup>Scott Meyers, Effective C++ Third Edition, Item 25: "Consider support for a non-throwing swap"</p>
|
||||
<p><sup><a id="ref2"/>[2]</sup><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#809">LWG issue 809 (std::swap should be overloaded for array types)</a></p>
|
||||
<p><sup><a id="ref2"/>[2]</sup><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#809">LWG Defect Report 809 (std::swap should be overloaded for array types)</a></p>
|
||||
|
||||
<!-- Copyright info -->
|
||||
<hr/>
|
||||
<p>Revised: 4 August 2008</p>
|
||||
<p>Revised: 08 September 2009</p>
|
||||
<p>
|
||||
Copyright 2007, 2008 Joseph Gauterin. Use, modification, and distribution are subject to the Boost Software License, Version 1.0.
|
||||
Copyright 2007 - 2009 Joseph Gauterin. Use, modification, and distribution are subject to 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">http://www.boost.org/LICENSE_1_0.txt</a>>.)
|
||||
</p>
|
||||
|
||||
|
@ -29,5 +29,9 @@ test-suite utility/swap
|
||||
[ run std_vector_of_global.cpp ../../../test/build//boost_test_exec_monitor/<link>static ]
|
||||
[ run std_vector_of_other.cpp ../../../test/build//boost_test_exec_monitor/<link>static ]
|
||||
[ run no_ambiguity_in_boost.cpp ../../../test/build//boost_test_exec_monitor/<link>static ]
|
||||
[ run swap_arrays.cpp ../../../test/build//boost_test_exec_monitor/<link>static ]
|
||||
[ run array_of_array_of_class.cpp ../../../test/build//boost_test_exec_monitor/<link>static ]
|
||||
[ run array_of_array_of_int.cpp ../../../test/build//boost_test_exec_monitor/<link>static ]
|
||||
[ run array_of_class.cpp ../../../test/build//boost_test_exec_monitor/<link>static ]
|
||||
[ run array_of_int.cpp ../../../test/build//boost_test_exec_monitor/<link>static ]
|
||||
[ run array_of_template.cpp ../../../test/build//boost_test_exec_monitor/<link>static ]
|
||||
;
|
||||
|
@ -4,6 +4,8 @@
|
||||
// (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
// Tests swapping an array of arrays of swap_test_class objects by means of boost::swap.
|
||||
|
||||
#include <boost/utility/swap.hpp>
|
||||
#define BOOST_INCLUDE_MAIN
|
||||
#include <boost/test/test_tools.hpp>
|
||||
@ -33,32 +35,8 @@ namespace std
|
||||
}
|
||||
}
|
||||
|
||||
// Tests swapping 1-dimensional arrays.
|
||||
void test_swapping_1D_arrays()
|
||||
{
|
||||
const std::size_t dimension = 2;
|
||||
const swap_test_class initial_array1[dimension] = { swap_test_class(1), swap_test_class(2) };
|
||||
const swap_test_class initial_array2[dimension] = { swap_test_class(3), swap_test_class(4) };
|
||||
|
||||
swap_test_class array1[dimension];
|
||||
swap_test_class array2[dimension];
|
||||
|
||||
std::copy(initial_array1, initial_array1 + dimension, array1);
|
||||
std::copy(initial_array2, initial_array2 + dimension, array2);
|
||||
|
||||
swap_test_class::reset();
|
||||
boost::swap(array1, array2);
|
||||
|
||||
BOOST_CHECK(std::equal(array1, array1 + dimension, initial_array2));
|
||||
BOOST_CHECK(std::equal(array2, array2 + dimension, initial_array1));
|
||||
|
||||
BOOST_CHECK_EQUAL(swap_test_class::swap_count(), dimension);
|
||||
BOOST_CHECK_EQUAL(swap_test_class::copy_count(), 0);
|
||||
}
|
||||
|
||||
|
||||
// Tests swapping 2-dimensional arrays.
|
||||
void test_swapping_2D_arrays()
|
||||
int test_main(int, char*[])
|
||||
{
|
||||
const std::size_t first_dimension = 3;
|
||||
const std::size_t second_dimension = 4;
|
||||
@ -76,7 +54,6 @@ void test_swapping_2D_arrays()
|
||||
ptr2[i].set_data( static_cast<int>(i + number_of_elements) );
|
||||
}
|
||||
|
||||
swap_test_class::reset();
|
||||
boost::swap(array1, array2);
|
||||
|
||||
for (std::size_t i = 0; i < number_of_elements; ++i)
|
||||
@ -87,14 +64,6 @@ void test_swapping_2D_arrays()
|
||||
|
||||
BOOST_CHECK_EQUAL(swap_test_class::swap_count(), number_of_elements);
|
||||
BOOST_CHECK_EQUAL(swap_test_class::copy_count(), 0);
|
||||
}
|
||||
|
||||
|
||||
int test_main(int, char*[])
|
||||
{
|
||||
test_swapping_1D_arrays();
|
||||
test_swapping_2D_arrays();
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
42
swap/test/array_of_array_of_int.cpp
Normal file
42
swap/test/array_of_array_of_int.cpp
Normal file
@ -0,0 +1,42 @@
|
||||
// Copyright (c) 2008 Joseph Gauterin, Niels Dekker
|
||||
//
|
||||
// Distributed under the Boost Software License, Version 1.0.
|
||||
// (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
// Tests swapping an array of arrays of integers by means of boost::swap.
|
||||
|
||||
#include <boost/utility/swap.hpp>
|
||||
#define BOOST_INCLUDE_MAIN
|
||||
#include <boost/test/test_tools.hpp>
|
||||
|
||||
#include <algorithm> //for std::copy and std::equal
|
||||
#include <cstddef> //for std::size_t
|
||||
|
||||
int test_main(int, char*[])
|
||||
{
|
||||
const std::size_t first_dimension = 3;
|
||||
const std::size_t second_dimension = 4;
|
||||
const std::size_t number_of_elements = first_dimension * second_dimension;
|
||||
|
||||
int array1[first_dimension][second_dimension];
|
||||
int array2[first_dimension][second_dimension];
|
||||
|
||||
int* const ptr1 = array1[0];
|
||||
int* const ptr2 = array2[0];
|
||||
|
||||
for (std::size_t i = 0; i < number_of_elements; ++i)
|
||||
{
|
||||
ptr1[i] = static_cast<int>(i);
|
||||
ptr2[i] = static_cast<int>(i + number_of_elements);
|
||||
}
|
||||
|
||||
boost::swap(array1, array2);
|
||||
|
||||
for (std::size_t i = 0; i < number_of_elements; ++i)
|
||||
{
|
||||
BOOST_CHECK_EQUAL(ptr1[i], static_cast<int>(i + number_of_elements) );
|
||||
BOOST_CHECK_EQUAL(ptr2[i], static_cast<int>(i) );
|
||||
}
|
||||
return 0;
|
||||
}
|
61
swap/test/array_of_class.cpp
Normal file
61
swap/test/array_of_class.cpp
Normal file
@ -0,0 +1,61 @@
|
||||
// Copyright (c) 2008 Joseph Gauterin, Niels Dekker
|
||||
//
|
||||
// Distributed under the Boost Software License, Version 1.0.
|
||||
// (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
// Tests swapping an array of arrays of swap_test_class objects by means of boost::swap.
|
||||
|
||||
#include <boost/utility/swap.hpp>
|
||||
#define BOOST_INCLUDE_MAIN
|
||||
#include <boost/test/test_tools.hpp>
|
||||
|
||||
//Put test class in the global namespace
|
||||
#include "./swap_test_class.hpp"
|
||||
|
||||
#include <algorithm> //for std::copy and std::equal
|
||||
#include <cstddef> //for std::size_t
|
||||
|
||||
//Provide swap function in both the namespace of swap_test_class
|
||||
//(which is the global namespace), and the std namespace.
|
||||
//It's common to provide a swap function for a class in both
|
||||
//namespaces. Scott Meyers recommends doing so: Effective C++,
|
||||
//Third Edition, item 25, "Consider support for a non-throwing swap".
|
||||
void swap(swap_test_class& left, swap_test_class& right)
|
||||
{
|
||||
left.swap(right);
|
||||
}
|
||||
|
||||
namespace std
|
||||
{
|
||||
template <>
|
||||
void swap(swap_test_class& left, swap_test_class& right)
|
||||
{
|
||||
left.swap(right);
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
int test_main(int, char*[])
|
||||
{
|
||||
const std::size_t array_size = 2;
|
||||
const swap_test_class initial_array1[array_size] = { swap_test_class(1), swap_test_class(2) };
|
||||
const swap_test_class initial_array2[array_size] = { swap_test_class(3), swap_test_class(4) };
|
||||
|
||||
swap_test_class array1[array_size];
|
||||
swap_test_class array2[array_size];
|
||||
|
||||
std::copy(initial_array1, initial_array1 + array_size, array1);
|
||||
std::copy(initial_array2, initial_array2 + array_size, array2);
|
||||
|
||||
swap_test_class::reset();
|
||||
boost::swap(array1, array2);
|
||||
|
||||
BOOST_CHECK(std::equal(array1, array1 + array_size, initial_array2));
|
||||
BOOST_CHECK(std::equal(array2, array2 + array_size, initial_array1));
|
||||
|
||||
BOOST_CHECK_EQUAL(swap_test_class::swap_count(), array_size);
|
||||
BOOST_CHECK_EQUAL(swap_test_class::copy_count(), 0);
|
||||
|
||||
return 0;
|
||||
}
|
35
swap/test/array_of_int.cpp
Normal file
35
swap/test/array_of_int.cpp
Normal file
@ -0,0 +1,35 @@
|
||||
// Copyright (c) 2008 Joseph Gauterin, Niels Dekker
|
||||
//
|
||||
// Distributed under the Boost Software License, Version 1.0.
|
||||
// (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
// Tests swapping an array of integers by means of boost::swap.
|
||||
|
||||
#include <boost/utility/swap.hpp>
|
||||
#define BOOST_INCLUDE_MAIN
|
||||
#include <boost/test/test_tools.hpp>
|
||||
|
||||
#include <algorithm> //for std::copy and std::equal
|
||||
#include <cstddef> //for std::size_t
|
||||
|
||||
|
||||
int test_main(int, char*[])
|
||||
{
|
||||
const std::size_t array_size = 3;
|
||||
const int initial_array1[array_size] = { 1, 2, 3 };
|
||||
const int initial_array2[array_size] = { 4, 5, 6 };
|
||||
|
||||
int array1[array_size];
|
||||
int array2[array_size];
|
||||
|
||||
std::copy(initial_array1, initial_array1 + array_size, array1);
|
||||
std::copy(initial_array2, initial_array2 + array_size, array2);
|
||||
|
||||
boost::swap(array1, array2);
|
||||
|
||||
BOOST_CHECK(std::equal(array1, array1 + array_size, initial_array2));
|
||||
BOOST_CHECK(std::equal(array2, array2 + array_size, initial_array1));
|
||||
|
||||
return 0;
|
||||
}
|
71
swap/test/array_of_template.cpp
Normal file
71
swap/test/array_of_template.cpp
Normal file
@ -0,0 +1,71 @@
|
||||
// Copyright (c) 2008 Joseph Gauterin, Niels Dekker
|
||||
//
|
||||
// Distributed under the Boost Software License, Version 1.0.
|
||||
// (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
// Tests swapping an array of swap_test_template<int> objects by means of boost::swap.
|
||||
|
||||
#include <boost/utility/swap.hpp>
|
||||
#define BOOST_INCLUDE_MAIN
|
||||
#include <boost/test/test_tools.hpp>
|
||||
|
||||
//Put test class in the global namespace
|
||||
#include "./swap_test_class.hpp"
|
||||
|
||||
#include <algorithm> //for std::copy and std::equal
|
||||
#include <cstddef> //for std::size_t
|
||||
|
||||
template <class T>
|
||||
class swap_test_template
|
||||
{
|
||||
public:
|
||||
typedef T template_argument;
|
||||
swap_test_class swap_test_object;
|
||||
};
|
||||
|
||||
template <class T>
|
||||
inline bool operator==(const swap_test_template<T> & lhs, const swap_test_template<T> & rhs)
|
||||
{
|
||||
return lhs.swap_test_object == rhs.swap_test_object;
|
||||
}
|
||||
|
||||
template <class T>
|
||||
inline bool operator!=(const swap_test_template<T> & lhs, const swap_test_template<T> & rhs)
|
||||
{
|
||||
return !(lhs == rhs);
|
||||
}
|
||||
|
||||
//Provide swap function in the namespace of swap_test_template
|
||||
//(which is the global namespace). Note that it isn't allowed to put
|
||||
//an overload of this function within the std namespace.
|
||||
template <class T>
|
||||
void swap(swap_test_template<T>& left, swap_test_template<T>& right)
|
||||
{
|
||||
left.swap_test_object.swap(right.swap_test_object);
|
||||
}
|
||||
|
||||
|
||||
int test_main(int, char*[])
|
||||
{
|
||||
const std::size_t array_size = 2;
|
||||
const swap_test_template<int> initial_array1[array_size] = { swap_test_class(1), swap_test_class(2) };
|
||||
const swap_test_template<int> initial_array2[array_size] = { swap_test_class(3), swap_test_class(4) };
|
||||
|
||||
swap_test_template<int> array1[array_size];
|
||||
swap_test_template<int> array2[array_size];
|
||||
|
||||
std::copy(initial_array1, initial_array1 + array_size, array1);
|
||||
std::copy(initial_array2, initial_array2 + array_size, array2);
|
||||
|
||||
swap_test_class::reset();
|
||||
boost::swap(array1, array2);
|
||||
|
||||
BOOST_CHECK(std::equal(array1, array1 + array_size, initial_array2));
|
||||
BOOST_CHECK(std::equal(array2, array2 + array_size, initial_array1));
|
||||
|
||||
BOOST_CHECK_EQUAL(swap_test_class::swap_count(), array_size);
|
||||
BOOST_CHECK_EQUAL(swap_test_class::copy_count(), 0);
|
||||
|
||||
return 0;
|
||||
}
|
@ -19,7 +19,7 @@ int test_main(int, char*[])
|
||||
typedef std::bitset<8> bitset_type;
|
||||
const bitset_type initial_value1 = 1ul;
|
||||
const bitset_type initial_value2 = 2ul;
|
||||
|
||||
|
||||
bitset_type object1 = initial_value1;
|
||||
bitset_type object2 = initial_value2;
|
||||
|
||||
|
@ -12,7 +12,7 @@
|
||||
|
||||
class swap_test_class
|
||||
{
|
||||
int m_data;
|
||||
int m_data;
|
||||
public:
|
||||
explicit swap_test_class(int arg = 0)
|
||||
:
|
||||
|
@ -11,7 +11,9 @@ import testing ;
|
||||
# Please keep the tests ordered by filename
|
||||
test-suite utility
|
||||
:
|
||||
[ run ../addressof_fn_test.cpp ]
|
||||
[ run ../addressof_test.cpp ]
|
||||
[ run ../addressof_test2.cpp ]
|
||||
[ run ../assert_test.cpp ]
|
||||
[ run ../base_from_member_test.cpp ]
|
||||
[ run ../binary_search_test.cpp ]
|
||||
|
@ -11,101 +11,35 @@
|
||||
#include <boost/static_assert.hpp>
|
||||
#include <boost/type_traits/is_same.hpp>
|
||||
|
||||
struct int_result_type
|
||||
{
|
||||
typedef int result_type;
|
||||
result_type operator()(float);
|
||||
};
|
||||
struct int_result_type { typedef int result_type; };
|
||||
|
||||
struct int_result_of
|
||||
{
|
||||
template<typename F> struct result { typedef int type; };
|
||||
result<int_result_of(double)>::type operator()(double);
|
||||
result<const int_result_of(double)>::type operator()(double) const;
|
||||
result<int_result_of()>::type operator()();
|
||||
result<volatile int_result_of()>::type operator()() volatile;
|
||||
};
|
||||
|
||||
struct int_result_type_and_float_result_of_and_char_return
|
||||
struct int_result_type_and_float_result_of
|
||||
{
|
||||
typedef int result_type;
|
||||
template<typename F> struct result { typedef float type; };
|
||||
char operator()(char);
|
||||
};
|
||||
|
||||
template<typename T>
|
||||
struct int_result_type_template
|
||||
{
|
||||
typedef int result_type;
|
||||
result_type operator()(float);
|
||||
};
|
||||
struct int_result_type_template { typedef int result_type; };
|
||||
|
||||
template<typename T>
|
||||
struct int_result_of_template
|
||||
{
|
||||
template<typename F> struct result;
|
||||
template<typename This, typename That> struct result<This(That)> { typedef int type; };
|
||||
typename result<int_result_of_template<T>(double)>::type operator()(double);
|
||||
typename result<const int_result_of_template<T>(double)>::type operator()(double) const;
|
||||
typename result<int_result_of_template<T>(double)>::type operator()();
|
||||
typename result<volatile int_result_of_template<T>(double)>::type operator()() volatile;
|
||||
};
|
||||
|
||||
template<typename T>
|
||||
struct int_result_type_and_float_result_of_and_char_return_template
|
||||
struct int_result_type_and_float_result_of_template
|
||||
{
|
||||
typedef int result_type;
|
||||
template<typename F> struct result;
|
||||
template<typename This, typename That> struct result<This(That)> { typedef float type; };
|
||||
char operator()(char);
|
||||
};
|
||||
|
||||
struct result_of_member_function_template
|
||||
{
|
||||
template<typename F> struct result;
|
||||
|
||||
template<typename This, typename That> struct result<This(That)> { typedef That type; };
|
||||
template<class T> typename result<result_of_member_function_template(T)>::type operator()(T);
|
||||
|
||||
template<typename This, typename That> struct result<const This(That)> { typedef const That type; };
|
||||
template<class T> typename result<const result_of_member_function_template(T)>::type operator()(T) const;
|
||||
|
||||
template<typename This, typename That> struct result<volatile This(That)> { typedef volatile That type; };
|
||||
template<class T> typename result<volatile result_of_member_function_template(T)>::type operator()(T) volatile;
|
||||
|
||||
template<typename This, typename That> struct result<const volatile This(That)> { typedef const volatile That type; };
|
||||
template<class T> typename result<const volatile result_of_member_function_template(T)>::type operator()(T) const volatile;
|
||||
|
||||
template<typename This, typename That> struct result<This(That &, That)> { typedef That & type; };
|
||||
template<class T> typename result<result_of_member_function_template(T &, T)>::type operator()(T &, T);
|
||||
|
||||
template<typename This, typename That> struct result<This(That const &, That)> { typedef That const & type; };
|
||||
template<class T> typename result<result_of_member_function_template(T const &, T)>::type operator()(T const &, T);
|
||||
|
||||
template<typename This, typename That> struct result<This(That volatile &, That)> { typedef That volatile & type; };
|
||||
template<class T> typename result<result_of_member_function_template(T volatile &, T)>::type operator()(T volatile &, T);
|
||||
|
||||
template<typename This, typename That> struct result<This(That const volatile &, That)> { typedef That const volatile & type; };
|
||||
template<class T> typename result<result_of_member_function_template(T const volatile &, T)>::type operator()(T const volatile &, T);
|
||||
};
|
||||
|
||||
struct no_result_type_or_result_of
|
||||
{
|
||||
int operator()(double);
|
||||
short operator()(double) const;
|
||||
unsigned int operator()();
|
||||
unsigned short operator()() volatile;
|
||||
const unsigned short operator()() const volatile;
|
||||
};
|
||||
|
||||
template<typename T>
|
||||
struct no_result_type_or_result_of_template
|
||||
{
|
||||
int operator()(double);
|
||||
short operator()(double) const;
|
||||
unsigned int operator()();
|
||||
unsigned short operator()() volatile;
|
||||
const unsigned short operator()() const volatile;
|
||||
};
|
||||
|
||||
struct X {};
|
||||
@ -126,37 +60,16 @@ int main()
|
||||
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<int_result_type(float)>::type, int>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<int_result_of(double)>::type, int>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<int_result_of(void)>::type, void>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<const int_result_of(double)>::type, int>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<volatile int_result_of(void)>::type, void>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of(char)>::type, int>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_template<void>(float)>::type, int>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<int_result_of_template<void>(double)>::type, int>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<const int_result_of_template<void>(double)>::type, int>::value));
|
||||
|
||||
// Prior to decltype, result_of could not deduce the return type
|
||||
// nullary function objects unless they exposed a result_type.
|
||||
#if defined(BOOST_HAS_DECLTYPE)
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<int_result_of(void)>::type, int>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<volatile int_result_of(void)>::type, int>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<int_result_of_template<void>(void)>::type, int>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<volatile int_result_of_template<void>(void)>::type, int>::value));
|
||||
#else
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<int_result_of(void)>::type, void>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<volatile int_result_of(void)>::type, void>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<int_result_of_template<void>(void)>::type, void>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<const int_result_of_template<void>(double)>::type, int>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<volatile int_result_of_template<void>(void)>::type, void>::value));
|
||||
#endif
|
||||
|
||||
// Prior to decltype, result_of ignored a nested result<> if
|
||||
// result_type was defined. After decltype, result_of deduces the
|
||||
// actual return type of the function object, ignoring both
|
||||
// result<> and result_type.
|
||||
#if defined(BOOST_HAS_DECLTYPE)
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of_and_char_return(char)>::type, char>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of_and_char_return_template<void>(char)>::type, char>::value));
|
||||
#else
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of_and_char_return(char)>::type, int>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of_and_char_return_template<void>(char)>::type, int>::value));
|
||||
#endif
|
||||
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of_template<void>(char)>::type, int>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<func_ptr(char, float)>::type, int>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<func_ref(char, float)>::type, int>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<func_ptr_0()>::type, int>::value));
|
||||
@ -168,31 +81,5 @@ int main()
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr_0(X)>::type, int>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<func_ptr(void)>::type, int>::value));
|
||||
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<result_of_member_function_template(double)>::type, double>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<const result_of_member_function_template(double)>::type, const double>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<volatile result_of_member_function_template(double)>::type, volatile double>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<const volatile result_of_member_function_template(double)>::type, const volatile double>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<result_of_member_function_template(int &, int)>::type, int &>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<result_of_member_function_template(int const &, int)>::type, int const &>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<result_of_member_function_template(int volatile &, int)>::type, int volatile &>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<result_of_member_function_template(int const volatile &, int)>::type, int const volatile &>::value));
|
||||
|
||||
typedef int (*pf_t)(int);
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<pf_t(int)>::type, int>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<pf_t const(int)>::type,int>::value));
|
||||
|
||||
#if defined(BOOST_HAS_DECLTYPE)
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of(double)>::type, int>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of(void)>::type, unsigned int>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<const no_result_type_or_result_of(double)>::type, short>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<volatile no_result_type_or_result_of(void)>::type, unsigned short>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<const volatile no_result_type_or_result_of(void)>::type, const unsigned short>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of_template<void>(double)>::type, int>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of_template<void>(void)>::type, unsigned int>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<const no_result_type_or_result_of_template<void>(double)>::type, short>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<volatile no_result_type_or_result_of_template<void>(void)>::type, unsigned short>::value));
|
||||
BOOST_STATIC_ASSERT((is_same<result_of<const volatile no_result_type_or_result_of_template<void>(void)>::type, const unsigned short>::value));
|
||||
#endif
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
@ -1,58 +1,15 @@
|
||||
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
|
||||
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||||
<html>
|
||||
<head>
|
||||
<title>Boost: throw_exception.hpp documentation</title>
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
|
||||
</head>
|
||||
<body bgcolor="white" style="MARGIN-LEFT: 5%; MARGIN-RIGHT: 5%">
|
||||
<table border="0" width="100%">
|
||||
<tr>
|
||||
<td width="277"><A href="../../index.htm"> <img src="../../boost.png" alt="boost.png (6897 bytes)" width="277" height="86" border="0"></A>
|
||||
</td>
|
||||
<td align="center">
|
||||
<h1>throw_exception.hpp</h1>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td colspan="2" height="64"> </td>
|
||||
</tr>
|
||||
</table>
|
||||
<p>
|
||||
The header <STRONG><boost/throw_exception.hpp></STRONG> defines the
|
||||
helper function <STRONG>boost::throw_exception</STRONG>. It is intended to be
|
||||
used in Boost libraries that need to throw exceptions, but support
|
||||
configurations and platforms where exceptions aren't available, as indicated by
|
||||
the presence of the <STRONG>BOOST_NO_EXCEPTIONS</STRONG> <A href="../config/config.htm#macro_ref">
|
||||
configuration macro</A>.
|
||||
</p>
|
||||
<P>When <STRONG>BOOST_NO_EXCEPTIONS</STRONG> is not defined, <tt>boost::throw_exception(e)</tt>
|
||||
is equivalent to <tt>throw e</tt>. Otherwise, the function is left undefined,
|
||||
and the user is expected to supply an appropriate definition. Callers of <tt>throw_exception</tt>
|
||||
are allowed to assume that the function never returns; therefore, if the
|
||||
user-defined <tt>throw_exception</tt> returns, the behavior is undefined.</P>
|
||||
<h3><a name="Synopsis">Synopsis</a></h3>
|
||||
<pre>
|
||||
namespace boost
|
||||
{
|
||||
|
||||
#ifdef BOOST_NO_EXCEPTIONS
|
||||
|
||||
void throw_exception(std::exception const & e); // user defined
|
||||
|
||||
#else
|
||||
|
||||
template<class E> void throw_exception(E const & e)
|
||||
{
|
||||
throw e;
|
||||
}
|
||||
|
||||
#endif
|
||||
|
||||
}
|
||||
</pre>
|
||||
<p><br>
|
||||
<small>Copyright <20> 2002 by Peter Dimov. Distributed under the Boost Software License, Version
|
||||
1.0. See accompanying file <A href="../../LICENSE_1_0.txt">LICENSE_1_0.txt</A> or
|
||||
copy at <A href="http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</A>.</small></p>
|
||||
</body>
|
||||
<head>
|
||||
<meta http-equiv=refresh content="0; URL=../exception/doc/throw_exception.html">
|
||||
<title>Automatic redirection</title>
|
||||
</head>
|
||||
<body>
|
||||
Automatic redirection failed, please go to
|
||||
<a href="../exception/doc/throw_exception.html">throw_exception.html</a>. <hr>
|
||||
<p><EFBFBD> Copyright Beman Dawes, 2001</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 copy
|
||||
at <a href="http://www.boost.org/LICENSE_1_0.txt">www.boost.org/LICENSE_1_0.txt</a>)</p>
|
||||
</body>
|
||||
</html>
|
||||
|
@ -154,13 +154,11 @@ void f() {
|
||||
...,t<em>N</em>)</code>. The implementation permits
|
||||
the type <code>F</code> to be a function pointer,
|
||||
function reference, member function pointer, or class
|
||||
type.</p> <p>If your compiler does not support
|
||||
<code>decltype</code>, then when <code>F</code> is a
|
||||
class type with a member type <code>result_type</code>,
|
||||
type. When <code>F</code> is a class type with a
|
||||
member type <code>result_type</code>,
|
||||
<code>result_of<F(T1, T2, ...,
|
||||
T<em>N</em>)></code> is
|
||||
<code>F::result_type</code>. When <code>F</code>
|
||||
does not contain <code>result_type</code>,
|
||||
<code>F::result_type</code>. Otherwise,
|
||||
<code>result_of<F(T1, T2, ...,
|
||||
T<em>N</em>)></code> is <code>F::result<F(T1,
|
||||
T2, ..., T<em>N</em>)>::type</code> when
|
||||
|
@ -253,7 +253,33 @@ its internal data, prior to constructing the object that it contains.
|
||||
|
||||
<h2><a name="val_init"><code>template class value_initialized<T></code></a></h2>
|
||||
|
||||
<pre>namespace boost {<br><br>template<class T><br>class value_initialized<br>{<br> public :<br> value_initialized() : x() {}<br> operator T&() const { return x ; }<br> T& data() const { return x ; }<br> void swap( value_initialized<T>& );<br><br> private :<br> <i>unspecified</i> x ;<br>} ;<br><br>template<class T><br>T const& get ( value_initialized<T> const& x )<br>{<br> return x.data() ;<br>}<br><br>template<class T><br>T& get ( value_initialized<T>& x )<br>{<br> return x.data() ;<br>}<br><br>} // namespace boost<br></pre>
|
||||
<pre>namespace boost {<br><br>template<class T><br>class value_initialized<br>{
|
||||
<br> public :
|
||||
<br> value_initialized() : x() {}
|
||||
<br> operator T const &() const { return x ; }
|
||||
<br> operator T&() { return x ; }
|
||||
<br> T const &data() const { return x ; }
|
||||
<br> T& data() { return x ; }
|
||||
<br> void swap( value_initialized<T>& );
|
||||
<br>
|
||||
<br> private :
|
||||
<br> <i>unspecified</i> x ;
|
||||
<br>} ;
|
||||
<br>
|
||||
<br>template<class T>
|
||||
<br>T const& get ( value_initialized<T> const& x )
|
||||
<br>{
|
||||
<br> return x.data() ;
|
||||
<br>}
|
||||
<br>
|
||||
<br>template<class T>
|
||||
<br>T& get ( value_initialized<T>& x )
|
||||
<br>{
|
||||
<br> return x.data() ;
|
||||
<br>}
|
||||
<br>
|
||||
<br>} // namespace boost
|
||||
<br></pre>
|
||||
|
||||
<p>An object of this template class is a <code>T</code>-wrapper convertible
|
||||
to <code>'T&'</code> whose wrapped object (data member of type <code>T</code>)
|
||||
@ -271,7 +297,8 @@ its internal data, prior to constructing the object that it contains.
|
||||
<code>T&</code>, the member function <code>data()</code>, or the
|
||||
non-member function <code>get()</code>: </p>
|
||||
|
||||
<pre>void watch(int);<br>value_initialized<int> x;<br><br>watch(x) ; // operator T& used.<br>watch(x.data());<br>watch( get(x) ) // function get() used</pre>
|
||||
<pre>void watch(int);<br>value_initialized<int> x;
|
||||
<br><br>watch(x) ; // operator T& used.<br>watch(x.data());<br>watch( get(x) ) // function get() used</pre>
|
||||
|
||||
<p>Both <code>const</code> and non-<code>const</code> objects can be wrapped.
|
||||
Mutable objects can be modified directly from within the wrapper but constant
|
||||
@ -281,37 +308,34 @@ non-member function <code>get()</code>: </p>
|
||||
is swappable as well, by calling its <code>swap</code> member function
|
||||
as well as by calling <code>boost::swap</code>.</p>
|
||||
|
||||
<pre>value_initialized<int> x ; <br>static_cast<int&>(x) = 1 ; // OK<br>get(x) = 1 ; // OK<br><br>value_initialized<int const> y ; <br>static_cast<int&>(y) = 1 ; // ERROR: cannot cast to int&<br>static_cast<int const&>(y) = 1 ; // ERROR: cannot modify a const value<br>get(y) = 1 ; // ERROR: cannot modify a const value</pre>
|
||||
<pre>value_initialized<int> x ; <br>static_cast<int&>(x) = 1 ; // OK<br>get(x) = 1 ; // OK
|
||||
<br><br>value_initialized<int const> y ; <br>static_cast<int&>(y) = 1 ; // ERROR: cannot cast to int&<br>static_cast<int const&>(y) = 1 ; // ERROR: cannot modify a const value<br>get(y) = 1 ; // ERROR: cannot modify a const value</pre>
|
||||
|
||||
<h3>Warning:</h3>
|
||||
|
||||
<p>Both the conversion operator and the <code>data()</code> member function
|
||||
are <code>const</code> in order to allow access to the wrapped object
|
||||
from a constant wrapper:</p>
|
||||
<p>The <code>value_initialized</code> implementation of Boost version 1.40.0 and older
|
||||
allowed <i>non-const</i> access to the wrapped object, from a constant wrapper,
|
||||
both by its conversion operator and its <code>data()</code> member function. For example:</p>
|
||||
|
||||
<pre>void foo(int);<br>value_initialized<int> const x ;<br>foo(x);<br></pre>
|
||||
<pre>value_initialized<int> const x_c ;<br>int& xr = x_c ; // OK, conversion to int& available even though x_c is itself const.
|
||||
<br>xr = 2 ; </pre>
|
||||
|
||||
<p>But notice that this conversion operator is to <code>T&</code> although
|
||||
it is itself <code>const</code>. As a consequence, if <code>T</code> is
|
||||
a non-<code>const</code> type, you can modify the wrapped object even from
|
||||
within a constant wrapper:</p>
|
||||
|
||||
<pre>value_initialized<int> const x_c ;<br>int& xr = x_c ; // OK, conversion to int& available even though x_c is itself const.<br>xr = 2 ; </pre>
|
||||
|
||||
<p>The reason for this obscure behavior is that some commonly used compilers
|
||||
just don't accept the following valid code:</p>
|
||||
<p>The reason for this obscure behavior was that some compilers
|
||||
didn't accept the following valid code:</p>
|
||||
|
||||
<pre>struct X<br>{<br> operator int&() ;<br> operator int const&() const ; <br>};<br>X x ;<br>(x == 1 ) ; // ERROR HERE!</pre>
|
||||
|
||||
<p>These compilers complain about ambiguity between the conversion operators.
|
||||
This complaint is incorrect, but the only workaround that I know of is
|
||||
to provide only one of them, which leads to the obscure behavior just explained.<br>
|
||||
<p>The current version of <code>value_initialized</code> no longer has this obscure behavior.
|
||||
As compilers nowadays widely support overloading the conversion operator by having a <code>const</code> and a <code>non-const</code> version, we have decided to fix the issue accordingly. So the current version supports the idea of logical constness.
|
||||
<br>
|
||||
</p>
|
||||
|
||||
<h3>Recommended practice: The non-member get() idiom</h3>
|
||||
|
||||
<p>The obscure behavior of being able to modify a non-<code>const</code>
|
||||
wrapped object from within a constant wrapper can be avoided if access to
|
||||
wrapped object from within a constant wrapper (as was supported by previous
|
||||
versions of <code>value_initialized</code>)
|
||||
can be avoided if access to
|
||||
the wrapped object is always performed with the <code>get()</code> idiom:</p>
|
||||
|
||||
<pre>value_initialized<int> x ;<br>get(x) = 1 ; // OK<br><br>value_initialized<int const> cx ;<br>get(x) = 1 ; // ERROR: Cannot modify a const object<br><br>value_initialized<int> const x_c ;<br>get(x_c) = 1 ; // ERROR: Cannot modify a const object<br><br>value_initialized<int const> const cx_c ;<br>get(cx_c) = 1 ; // ERROR: Cannot modify a const object<br></pre>
|
||||
@ -383,9 +407,9 @@ for Boost release version 1.35 (2008), offering a workaround to various compiler
|
||||
</p>
|
||||
|
||||
<hr>
|
||||
<p>Revised 28 August 2008</p>
|
||||
<p>Revised 03 October 2009</p>
|
||||
|
||||
<p>© Copyright Fernando Cacciola, 2002, 2008.</p>
|
||||
<p>© Copyright Fernando Cacciola, 2002, 2009.</p>
|
||||
|
||||
<p>Distributed under the Boost Software License, Version 1.0. See
|
||||
<a href="http://www.boost.org/LICENSE_1_0.txt">www.boost.org/LICENSE_1_0.txt</a></p>
|
||||
@ -394,4 +418,4 @@ for Boost release version 1.35 (2008), offering a workaround to various compiler
|
||||
<br>
|
||||
|
||||
</body>
|
||||
</html>
|
||||
</html>
|
||||
|
@ -260,7 +260,7 @@ bool test ( T const& y, T const& z )
|
||||
boost::value_initialized<T> const x_c ;
|
||||
BOOST_CHECK ( y == x_c ) ;
|
||||
BOOST_CHECK ( y == boost::get(x_c) ) ;
|
||||
T& x_c_ref = x_c ;
|
||||
T& x_c_ref = const_cast<T&>( boost::get(x_c) ) ;
|
||||
x_c_ref = z ;
|
||||
BOOST_CHECK ( x_c == z ) ;
|
||||
|
||||
|
Reference in New Issue
Block a user