1 #ifndef BOOST_TT_IS_ABSTRACT_CLASS_HPP
2 #define BOOST_TT_IS_ABSTRACT_CLASS_HPP
8 /////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8
9 // is_abstract_class.hpp:
11 // (C) Copyright 2002 Rani Sharoni (rani_sharoni@hotmail.com) and Robert Ramey
12 // Use, modification and distribution is subject to the Boost Software
13 // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
14 // http://www.boost.org/LICENSE_1_0.txt)
16 // See http://www.boost.org for updates, documentation, and revision history.
19 // Compile type discovery whether given type is abstract class or not.
21 // Requires DR 337 to be supported by compiler
22 // (http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#337).
25 // Believed (Jan 2004) to work on:
28 // - compilers with new EDG frontend (Intel C++ 7, Comeau 4.3.2)
31 // - VC++6, VC++7.0 and less
32 // - GCC 3.3.X and less
33 // - Borland C++ 6 and less
37 // - Originally written by Rani Sharoni, see
38 // http://groups.google.com/groups?selm=df893da6.0207110613.75b2fe90%40posting.google.com
39 // At this time supported by EDG (Intel C++ 7, Comeau 4.3.2) and VC7.1.
40 // - Adapted and added into Boost.Serialization library by Robert Ramey
41 // (starting with submission #10).
42 // - Jan 2004: GCC 3.4 fixed to support DR337 (Giovanni Bajo).
43 // - Jan 2004: modified to be part of Boost.TypeTraits (Pavel Vozenilek).
44 // - Nov 2004: Christoph Ludwig found that the implementation did not work with
45 // template types and gcc-3.4 or VC7.1, fix due to Christoph Ludwig
47 // - Dec 2004: Added new config macro BOOST_NO_IS_ABSTRACT which causes the template
48 // to degrade gracefully, rather than trash the compiler (John Maddock).
51 #include <cstddef> // size_t
52 #include <boost/type_traits/intrinsics.hpp>
53 #include <boost/type_traits/integral_constant.hpp>
54 #ifndef BOOST_IS_ABSTRACT
55 #include <boost/static_assert.hpp>
56 #include <boost/type_traits/detail/yes_no_type.hpp>
57 #include <boost/type_traits/is_class.hpp>
58 #ifdef BOOST_NO_IS_ABSTRACT
59 #include <boost/type_traits/is_polymorphic.hpp>
67 #ifdef BOOST_IS_ABSTRACT
69 struct is_abstract_imp
71 BOOST_STATIC_CONSTANT(bool, value = BOOST_IS_ABSTRACT(T));
73 #elif !defined(BOOST_NO_IS_ABSTRACT)
75 struct is_abstract_imp2
77 // Deduction fails if T is void, function type,
78 // reference type (14.8.2/2)or an abstract class type
79 // according to review status issue #337
82 static type_traits::no_type check_sig(U (*)[1]);
84 static type_traits::yes_type check_sig(...);
86 // T must be a complete type, further if T is a template then
87 // it must be instantiated in order for us to get the right answer:
89 BOOST_STATIC_ASSERT(sizeof(T) != 0);
91 // GCC2 won't even parse this template if we embed the computation
92 // of s1 in the computation of value.
94 BOOST_STATIC_CONSTANT(std::size_t, s1 = sizeof(is_abstract_imp2<T>::template check_sig<T>(0)));
96 #if BOOST_WORKAROUND(BOOST_MSVC_FULL_VER, >= 140050000)
98 #pragma warning(disable:6334)
100 BOOST_STATIC_CONSTANT(std::size_t, s1 = sizeof(check_sig<T>(0)));
101 #if BOOST_WORKAROUND(BOOST_MSVC_FULL_VER, >= 140050000)
106 BOOST_STATIC_CONSTANT(bool, value =
107 (s1 == sizeof(type_traits::yes_type)));
111 struct is_abstract_select
116 typedef is_abstract_imp2<T> type;
120 struct is_abstract_select<false>
125 typedef false_type type;
130 struct is_abstract_imp
132 typedef is_abstract_select< ::boost::is_class<T>::value> selector;
133 typedef typename selector::template rebind<T> binder;
134 typedef typename binder::type type;
136 BOOST_STATIC_CONSTANT(bool, value = type::value);
142 #ifndef BOOST_NO_IS_ABSTRACT
143 template <class T> struct is_abstract : public integral_constant<bool, ::boost::detail::is_abstract_imp<T>::value> {};
145 template <class T> struct is_abstract : public integral_constant<bool, ::boost::detail::is_polymorphic_imp<T>::value> {};
150 #endif //BOOST_TT_IS_ABSTRACT_CLASS_HPP