1 2 // (C) Copyright Dave Abrahams, Steve Cleary, Beman Dawes, 3 // Howard Hinnant and John Maddock 2000. 4 // (C) Copyright Mat Marcus, Jesse Jones and Adobe Systems Inc 2001 5 6 // Use, modification and distribution are subject to the Boost Software License, 7 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at 8 // http://www.boost.org/LICENSE_1_0.txt). 9 // 10 // See http://www.boost.org/libs/type_traits for most recent version including documentation. 11 12 // Fixed is_pointer, is_lvalue_reference, is_const, is_volatile, is_same, 13 // is_member_pointer based on the Simulated Partial Specialization work 14 // of Mat Marcus and Jesse Jones. See http://opensource.adobe.com or 15 // http://groups.yahoo.com/group/boost/message/5441 16 // Some workarounds in here use ideas suggested from "Generic<Programming>: 17 // Mappings between Types and Values" 18 // by Andrei Alexandrescu (see http://www.cuj.com/experts/1810/alexandr.html). 19 20 21 #ifndef BOOST_TT_IS_LVALUE_REFERENCE_HPP_INCLUDED 22 #define BOOST_TT_IS_LVALUE_REFERENCE_HPP_INCLUDED 23 24 #include <boost/type_traits/config.hpp> 25 26 #ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION 27 # include <boost/type_traits/detail/yes_no_type.hpp> 28 # include <boost/type_traits/detail/wrap.hpp> 29 #endif 30 31 // should be the last #include 32 #include <boost/type_traits/detail/bool_trait_def.hpp> 33 34 namespace boost { 35 36 #if defined( __CODEGEARC__ ) 37 BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_lvalue_reference,T,__is_reference(T)) 38 #elif !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) 39 40 BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_lvalue_reference,T,false) 41 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_lvalue_reference,T&,true) 42 43 #if defined(BOOST_ILLEGAL_CV_REFERENCES) 44 // these are illegal specialisations; cv-qualifies applied to 45 // references have no effect according to [8.3.2p1], 46 // C++ Builder requires them though as it treats cv-qualified 47 // references as distinct types... 48 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_lvalue_reference,T& const,true) 49 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_lvalue_reference,T& volatile,true) 50 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_lvalue_reference,T& const volatile,true) 51 #endif 52 53 #if defined(__GNUC__) && (__GNUC__ < 3) 54 // these allow us to work around illegally cv-qualified reference 55 // types. 56 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_lvalue_reference,T const ,::boost::is_lvalue_reference<T>::value) 57 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_lvalue_reference,T volatile ,::boost::is_lvalue_reference<T>::value) 58 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_lvalue_reference,T const volatile ,::boost::is_lvalue_reference<T>::value) 59 // However, the above specializations confuse gcc 2.96 unless we also 60 // supply these specializations for array types 61 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_2(typename T,unsigned long N,is_lvalue_reference,T[N],false) 62 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_2(typename T,unsigned long N,is_lvalue_reference,const T[N],false) 63 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_2(typename T,unsigned long N,is_lvalue_reference,volatile T[N],false) 64 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_2(typename T,unsigned long N,is_lvalue_reference,const volatile T[N],false) 65 #endif 66 67 #else 68 69 #ifdef BOOST_MSVC 70 # pragma warning(push) 71 # pragma warning(disable: 4181 4097) 72 #endif 73 74 namespace detail { 75 76 using ::boost::type_traits::yes_type; 77 using ::boost::type_traits::no_type; 78 using ::boost::type_traits::wrap; 79 80 template <class T> T&(* is_lvalue_reference_helper1(wrap<T>) )(wrap<T>); 81 char is_lvalue_reference_helper1(...); 82 83 template <class T> no_type is_lvalue_reference_helper2(T&(*)(wrap<T>)); 84 yes_type is_lvalue_reference_helper2(...); 85 86 template <typename T> 87 struct is_lvalue_reference_impl 88 { 89 BOOST_STATIC_CONSTANT( 90 bool, value = sizeof( 91 ::boost::detail::is_lvalue_reference_helper2( 92 ::boost::detail::is_lvalue_reference_helper1(::boost::type_traits::wrap<T>()))) == 1 93 ); 94 }; 95 96 BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_lvalue_reference,void,false) 97 #ifndef BOOST_NO_CV_VOID_SPECIALIZATIONS 98 BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_lvalue_reference,void const,false) 99 BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_lvalue_reference,void volatile,false) 100 BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_lvalue_reference,void const volatile,false) 101 #endif 102 103 } // namespace detail 104 105 BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_lvalue_reference,T,::boost::detail::is_lvalue_reference_impl<T>::value) 106 107 #ifdef BOOST_MSVC 108 # pragma warning(pop) 109 #endif 110 111 #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION 112 113 } // namespace boost 114 115 #include <boost/type_traits/detail/bool_trait_undef.hpp> 116 117 #endif // BOOST_TT_IS_REFERENCE_HPP_INCLUDED 118 119
