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HasMemberGeneratorMacros.hpp
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1 // -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
2 // vi: set et ts=4 sw=4 sts=4:
3 /*
4  This file is part of the Open Porous Media project (OPM).
5 
6  OPM is free software: you can redistribute it and/or modify
7  it under the terms of the GNU General Public License as published by
8  the Free Software Foundation, either version 2 of the License, or
9  (at your option) any later version.
10 
11  OPM 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.
15 
16  You should have received a copy of the GNU General Public License
17  along with OPM. If not, see <http://www.gnu.org/licenses/>.
18 
19  Consult the COPYING file in the top-level source directory of this
20  module for the precise wording of the license and the list of
21  copyright holders.
22 */
28 #ifndef OPM_HAS_MEMBER_GENERATOR_MACROS_HH
29 #define OPM_HAS_MEMBER_GENERATOR_MACROS_HH
30 
32 namespace Opm {
33 template <class T>
34 struct AlwaysVoid
35 {
36  typedef void type;
37 };
38 }
40 
49 #define OPM_GENERATE_HAS_MEMBER(MEMBER_NAME, ...) \
50  template <class T, class T2> \
51  struct HasMember_##MEMBER_NAME##_Helper \
52  { \
53  static constexpr bool value = false; \
54  }; \
55  \
56  template <class T> \
57  struct HasMember_##MEMBER_NAME##_Helper<T, \
58  typename ::Opm::AlwaysVoid<decltype(std::declval<T>().MEMBER_NAME(__VA_ARGS__))>::type> \
59  { \
60  static constexpr bool value = true; \
61  }; \
62  \
63  template<typename T> \
64  struct HasMember_##MEMBER_NAME \
65  { \
66  static constexpr bool value = HasMember_##MEMBER_NAME##_Helper<T, void>::value; \
67  };
68 
69 #endif