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
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).
10 // See http://www.boost.org/libs/type_traits for most recent version including documentation.
12 // Fixed is_pointer, is_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).
21 #ifndef BOOST_TT_IS_CONST_HPP_INCLUDED
22 #define BOOST_TT_IS_CONST_HPP_INCLUDED
24 #include <boost/config.hpp>
25 #include <boost/detail/workaround.hpp>
27 #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
28 # include <boost/type_traits/detail/cv_traits_impl.hpp>
30 # include <boost/type_traits/is_reference.hpp>
32 # if BOOST_WORKAROUND(BOOST_MSVC, < 1400)
33 # include <boost/type_traits/remove_bounds.hpp>
36 # include <boost/type_traits/is_reference.hpp>
37 # include <boost/type_traits/is_array.hpp>
38 # include <boost/type_traits/detail/yes_no_type.hpp>
39 # include <boost/type_traits/detail/false_result.hpp>
42 // should be the last #include
43 #include <boost/type_traits/detail/bool_trait_def.hpp>
47 #if defined( __CODEGEARC__ )
49 BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_const,T,__is_const(T))
51 #elif !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
55 // We can't filter out rvalue_references at the same level as
56 // references or we get ambiguities from msvc:
59 struct is_const_rvalue_filter
61 #if BOOST_WORKAROUND(BOOST_MSVC, < 1400)
62 BOOST_STATIC_CONSTANT(bool, value = ::boost::detail::cv_traits_imp<typename boost::remove_bounds<T>::type*>::is_const);
64 BOOST_STATIC_CONSTANT(bool, value = ::boost::detail::cv_traits_imp<T*>::is_const);
67 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
69 struct is_const_rvalue_filter<T&&>
71 BOOST_STATIC_CONSTANT(bool, value = false);
76 //* is a type T declared const - is_const<T>
77 BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_const,T,::boost::detail::is_const_rvalue_filter<T>::value)
78 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_const,T&,false)
80 #if defined(BOOST_ILLEGAL_CV_REFERENCES)
81 // these are illegal specialisations; cv-qualifies applied to
82 // references have no effect according to [8.3.2p1],
83 // C++ Builder requires them though as it treats cv-qualified
84 // references as distinct types...
85 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_const,T& const,false)
86 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_const,T& volatile,false)
87 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_const,T& const volatile,false)
90 #if defined(__GNUC__) && (__GNUC__ < 3)
91 // special case for gcc where illegally cv-qualified reference types can be
92 // generated in some corner cases:
93 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_const,T const,!(::boost::is_reference<T>::value))
94 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_const,T volatile const,!(::boost::is_reference<T>::value))
101 using ::boost::type_traits::yes_type;
102 using ::boost::type_traits::no_type;
104 yes_type is_const_tester(const volatile void*);
105 no_type is_const_tester(volatile void *);
107 template <bool is_ref, bool array>
108 struct is_const_helper
109 : public ::boost::type_traits::false_result
114 struct is_const_helper<false,false>
116 template <typename T> struct result_
119 BOOST_STATIC_CONSTANT(bool, value = (
120 sizeof(boost::detail::yes_type) == sizeof(boost::detail::is_const_tester(t))
126 struct is_const_helper<false,true>
128 template <typename T> struct result_
131 BOOST_STATIC_CONSTANT(bool, value = (
132 sizeof(boost::detail::yes_type) == sizeof(boost::detail::is_const_tester(&t))
137 template <typename T>
139 : public is_const_helper<
140 is_reference<T>::value
142 >::template result_<T>
146 BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_const,void,false)
147 #ifndef BOOST_NO_CV_VOID_SPECIALIZATIONS
148 BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_const,void const,true)
149 BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_const,void volatile,false)
150 BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_const,void const volatile,true)
153 } // namespace detail
155 //* is a type T declared const - is_const<T>
156 BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_const,T,::boost::detail::is_const_impl<T>::value)
158 #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
162 #include <boost/type_traits/detail/bool_trait_undef.hpp>
164 #endif // BOOST_TT_IS_CONST_HPP_INCLUDED