1 // TR2 <type_traits> -*- C++ -*-
3 // Copyright (C) 2011 Free Software Foundation, Inc.
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
25 /** @file tr2/type_traits
26 * This is a TR2 C++ Library header.
29 #ifndef _GLIBCXX_TR2_TYPE_TRAITS
30 #define _GLIBCXX_TR2_TYPE_TRAITS 1
32 #pragma GCC system_header
33 #include <type_traits>
34 #include <bits/c++config.h>
36 namespace std _GLIBCXX_VISIBILITY(default)
40 _GLIBCXX_BEGIN_NAMESPACE_VERSION
43 * @addtogroup metaprogramming
48 * See N2965: Type traits and base classes
53 * Simple typelist. Compile-time list of types.
55 template<typename... _Elements>
58 /// Specialization for an empty typelist.
62 typedef std::true_type empty;
65 /// Partial specialization.
66 template<typename _First, typename... _Rest>
67 struct typelist<_First, _Rest...>
69 typedef std::false_type empty;
78 typedef typelist<_Rest...> type;
82 /// Sequence abstraction metafunctions for manipulating a typelist.
85 /// Return the first type in a typelist.
86 template<typename _Tp>
87 struct first : public _Tp::first { };
89 /// Return the typelist minus the first type.
90 template<typename _Tp>
91 struct rest : public _Tp::rest { };
93 /// Query to see if a typelist is empty.
94 template<typename _Tp>
95 struct empty : public _Tp::empty { };
98 /// Enumerate all the base classes of a class. Form of a typelist.
99 template<typename _Tp>
102 typedef typelist<__bases(_Tp)...> type;
105 /// Enumerate all the direct base classes of a class. Form of a typelist.
106 template<typename _Tp>
109 typedef typelist<__direct_bases(_Tp)...> type;
112 /// @} group metaprogramming
114 _GLIBCXX_END_NAMESPACE_VERSION
118 #endif // _GLIBCXX_TR2_TYPE_TRAITS