1 2 #ifndef BOOST_MPL_AUX_MSVC_IS_CLASS_HPP_INCLUDED 3 #define BOOST_MPL_AUX_MSVC_IS_CLASS_HPP_INCLUDED 4 5 // Copyright Aleksey Gurtovoy 2002-2004 6 // 7 // Distributed under the Boost Software License, Version 1.0. 8 // (See accompanying file LICENSE_1_0.txt or copy at 9 // http://www.boost.org/LICENSE_1_0.txt) 10 // 11 // See http://www.boost.org/libs/mpl for documentation. 12 13 // $Id$ 14 // $Date$ 15 // $Revision$ 16 17 #include <boost/mpl/if.hpp> 18 #include <boost/mpl/bool.hpp> 19 #include <boost/mpl/aux_/type_wrapper.hpp> 20 #include <boost/mpl/aux_/yes_no.hpp> 21 22 #include <boost/type_traits/is_reference.hpp> 23 24 namespace boost { namespace mpl { namespace aux { 25 26 template< typename T > struct is_class_helper 27 { 28 typedef int (T::* type)(); 29 }; 30 31 // MSVC 6.x-specific lightweight 'is_class' implementation; 32 // Distinguishing feature: does not instantiate the type being tested. 33 template< typename T > 34 struct msvc_is_class_impl 35 { 36 template< typename U> 37 static yes_tag test(type_wrapper<U>*, /*typename*/ is_class_helper<U>::type = 0); 38 static no_tag test(void const volatile*, ...); 39 40 enum { value = sizeof(test((type_wrapper<T>*)0)) == sizeof(yes_tag) }; 41 typedef bool_<value> type; 42 }; 43 44 // agurt, 17/sep/04: have to check for 'is_reference' upfront to avoid ICEs in 45 // complex metaprograms 46 template< typename T > 47 struct msvc_is_class 48 : if_< 49 is_reference<T> 50 , false_ 51 , msvc_is_class_impl<T> 52 >::type 53 { 54 }; 55 56 }}} 57 58 #endif // BOOST_MPL_AUX_MSVC_IS_CLASS_HPP_INCLUDED 59