275 lines
8.4 KiB
C++
275 lines
8.4 KiB
C++
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#ifndef BOOST_MPL_HAS_XXX_HPP_INCLUDED
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#define BOOST_MPL_HAS_XXX_HPP_INCLUDED
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// Copyright Aleksey Gurtovoy 2002-2006
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// Copyright David Abrahams 2002-2003
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//
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// 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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// http://www.boost.org/LICENSE_1_0.txt)
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//
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// See http://www.boost.org/libs/mpl for documentation.
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// $Id: has_xxx.hpp 49273 2008-10-11 06:54:06Z agurtovoy $
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// $Date: 2008-10-11 02:54:06 -0400 (Sat, 11 Oct 2008) $
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// $Revision: 49273 $
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#include <boost/mpl/bool.hpp>
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#include <boost/mpl/aux_/type_wrapper.hpp>
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#include <boost/mpl/aux_/yes_no.hpp>
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#include <boost/mpl/aux_/config/has_xxx.hpp>
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#include <boost/mpl/aux_/config/msvc_typename.hpp>
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#include <boost/mpl/aux_/config/msvc.hpp>
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#include <boost/mpl/aux_/config/static_constant.hpp>
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#include <boost/mpl/aux_/config/workaround.hpp>
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#include <boost/preprocessor/cat.hpp>
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#if BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT(0x590) )
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# include <boost/type_traits/is_class.hpp>
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#endif
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#if !defined(BOOST_MPL_CFG_NO_HAS_XXX)
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# if BOOST_WORKAROUND(BOOST_MSVC, <= 1300)
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// agurt, 11/sep/02: MSVC-specific version (< 7.1), based on a USENET
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// newsgroup's posting by John Madsen (comp.lang.c++.moderated,
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// 1999-11-12 19:17:06 GMT); the code is _not_ standard-conforming, but
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// it works way more reliably than the SFINAE-based implementation
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// Modified dwa 8/Oct/02 to handle reference types.
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# include <boost/mpl/if.hpp>
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# include <boost/mpl/bool.hpp>
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namespace boost { namespace mpl { namespace aux {
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struct has_xxx_tag;
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#if BOOST_WORKAROUND(BOOST_MSVC, == 1300)
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template< typename U > struct msvc_incomplete_array
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{
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typedef char (&type)[sizeof(U) + 1];
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};
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#endif
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template< typename T >
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struct msvc_is_incomplete
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{
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// MSVC is capable of some kinds of SFINAE. If U is an incomplete
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// type, it won't pick the second overload
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static char tester(...);
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#if BOOST_WORKAROUND(BOOST_MSVC, == 1300)
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template< typename U >
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static typename msvc_incomplete_array<U>::type tester(type_wrapper<U>);
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#else
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template< typename U >
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static char (& tester(type_wrapper<U>) )[sizeof(U)+1];
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#endif
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BOOST_STATIC_CONSTANT(bool, value =
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sizeof(tester(type_wrapper<T>())) == 1
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);
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};
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template<>
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struct msvc_is_incomplete<int>
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{
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BOOST_STATIC_CONSTANT(bool, value = false);
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};
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}}}
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# define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF_(trait, name, default_) \
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template< typename T, typename name = ::boost::mpl::aux::has_xxx_tag > \
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struct BOOST_PP_CAT(trait,_impl) : T \
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{ \
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static boost::mpl::aux::no_tag \
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test(void(*)(::boost::mpl::aux::has_xxx_tag)); \
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\
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static boost::mpl::aux::yes_tag test(...); \
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\
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BOOST_STATIC_CONSTANT(bool, value = \
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sizeof(test(static_cast<void(*)(name)>(0))) \
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!= sizeof(boost::mpl::aux::no_tag) \
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); \
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typedef boost::mpl::bool_<value> type; \
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}; \
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\
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template< typename T, typename fallback_ = boost::mpl::bool_<default_> > \
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struct trait \
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: boost::mpl::if_c< \
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boost::mpl::aux::msvc_is_incomplete<T>::value \
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, boost::mpl::bool_<false> \
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, BOOST_PP_CAT(trait,_impl)<T> \
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>::type \
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{ \
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}; \
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\
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BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, void) \
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BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, bool) \
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BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, char) \
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BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, signed char) \
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BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, unsigned char) \
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BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, signed short) \
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BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, unsigned short) \
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BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, signed int) \
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BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, unsigned int) \
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BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, signed long) \
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BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, unsigned long) \
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BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, float) \
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BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, double) \
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BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, long double) \
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/**/
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# define BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, T) \
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template<> struct trait<T> \
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{ \
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BOOST_STATIC_CONSTANT(bool, value = false); \
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typedef boost::mpl::bool_<false> type; \
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}; \
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/**/
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#if !defined(BOOST_NO_INTRINSIC_WCHAR_T)
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# define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(trait, name, unused) \
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BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF_(trait, name, unused) \
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BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, wchar_t) \
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/**/
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#else
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# define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(trait, name, unused) \
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BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF_(trait, name, unused) \
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/**/
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#endif
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// SFINAE-based implementations below are derived from a USENET newsgroup's
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// posting by Rani Sharoni (comp.lang.c++.moderated, 2002-03-17 07:45:09 PST)
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# elif BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1400)) \
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|| BOOST_WORKAROUND(__IBMCPP__, <= 700)
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// MSVC 7.1+ & VACPP
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// agurt, 15/jun/05: replace overload-based SFINAE implementation with SFINAE
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// applied to partial specialization to fix some apparently random failures
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// (thanks to Daniel Wallin for researching this!)
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# define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(trait, name, default_) \
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template< typename T > \
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struct BOOST_PP_CAT(trait, _msvc_sfinae_helper) \
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{ \
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typedef void type; \
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};\
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\
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template< typename T, typename U = void > \
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struct BOOST_PP_CAT(trait,_impl_) \
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{ \
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BOOST_STATIC_CONSTANT(bool, value = false); \
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typedef boost::mpl::bool_<value> type; \
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}; \
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\
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template< typename T > \
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struct BOOST_PP_CAT(trait,_impl_)< \
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T \
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, typename BOOST_PP_CAT(trait, _msvc_sfinae_helper)< typename T::name >::type \
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> \
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{ \
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BOOST_STATIC_CONSTANT(bool, value = true); \
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typedef boost::mpl::bool_<value> type; \
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}; \
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\
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template< typename T, typename fallback_ = boost::mpl::bool_<default_> > \
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struct trait \
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: BOOST_PP_CAT(trait,_impl_)<T> \
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{ \
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}; \
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/**/
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# elif BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT(0x590) )
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# define BOOST_MPL_HAS_XXX_TRAIT_NAMED_BCB_DEF(trait, trait_tester, name, default_) \
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template< typename T, bool IS_CLASS > \
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struct trait_tester \
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{ \
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BOOST_STATIC_CONSTANT( bool, value = false ); \
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}; \
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template< typename T > \
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struct trait_tester< T, true > \
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{ \
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struct trait_tester_impl \
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{ \
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template < class U > \
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static int resolve( boost::mpl::aux::type_wrapper<U> const volatile * \
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, boost::mpl::aux::type_wrapper<typename U::name >* = 0 ); \
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static char resolve( ... ); \
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}; \
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typedef boost::mpl::aux::type_wrapper<T> t_; \
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BOOST_STATIC_CONSTANT( bool, value = ( sizeof( trait_tester_impl::resolve( static_cast< t_ * >(0) ) ) == sizeof(int) ) ); \
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}; \
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template< typename T, typename fallback_ = boost::mpl::bool_<default_> > \
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struct trait \
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{ \
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BOOST_STATIC_CONSTANT( bool, value = (trait_tester< T, boost::is_class< T >::value >::value) ); \
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typedef boost::mpl::bool_< trait< T, fallback_ >::value > type; \
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};
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# define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(trait, name, default_) \
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BOOST_MPL_HAS_XXX_TRAIT_NAMED_BCB_DEF( trait \
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, BOOST_PP_CAT(trait,_tester) \
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, name \
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, default_ ) \
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/**/
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# else // other SFINAE-capable compilers
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# define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(trait, name, default_) \
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template< typename T, typename fallback_ = boost::mpl::bool_<default_> > \
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struct trait \
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{ \
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struct gcc_3_2_wknd \
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{ \
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template< typename U > \
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static boost::mpl::aux::yes_tag test( \
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boost::mpl::aux::type_wrapper<U> const volatile* \
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, boost::mpl::aux::type_wrapper<BOOST_MSVC_TYPENAME U::name>* = 0 \
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); \
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\
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static boost::mpl::aux::no_tag test(...); \
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}; \
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\
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typedef boost::mpl::aux::type_wrapper<T> t_; \
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BOOST_STATIC_CONSTANT(bool, value = \
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sizeof(gcc_3_2_wknd::test(static_cast<t_*>(0))) \
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== sizeof(boost::mpl::aux::yes_tag) \
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); \
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typedef boost::mpl::bool_<value> type; \
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}; \
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/**/
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# endif // BOOST_WORKAROUND(BOOST_MSVC, <= 1300)
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#else // BOOST_MPL_CFG_NO_HAS_XXX
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// placeholder implementation
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# define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(trait, name, default_) \
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template< typename T, typename fallback_ = boost::mpl::bool_<default_> > \
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struct trait \
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{ \
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BOOST_STATIC_CONSTANT(bool, value = fallback_::value); \
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typedef fallback_ type; \
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}; \
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/**/
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#endif
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#define BOOST_MPL_HAS_XXX_TRAIT_DEF(name) \
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BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(BOOST_PP_CAT(has_,name), name, false) \
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/**/
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#endif // BOOST_MPL_HAS_XXX_HPP_INCLUDED
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