1 // Copyright David Abrahams 2006. Distributed under the Boost
2 // Software License, Version 1.0. (See accompanying
3 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
4 #ifndef BOOST_CONCEPT_DETAIL_GENERAL_DWA2006429_HPP
5 # define BOOST_CONCEPT_DETAIL_GENERAL_DWA2006429_HPP
6 
7 # include <boost/preprocessor/cat.hpp>
8 # include <boost/concept/detail/backward_compatibility.hpp>
9 
10 # ifdef BOOST_OLD_CONCEPT_SUPPORT
11 #  include <boost/concept/detail/has_constraints.hpp>
12 #  include <boost/mpl/if.hpp>
13 # endif
14 
15 // This implementation works on Comeau and GCC, all the way back to
16 // 2.95
17 namespace boost { namespace concepts {
18 
19 template <class ModelFn>
20 struct requirement_;
21 
22 namespace detail
23 {
24   template <void(*)()> struct instantiate {};
25 }
26 
27 template <class Model>
28 struct requirement
29 {
failedboost::concepts::requirement30     static void failed() { ((Model*)0)->~Model(); }
31 };
32 
33 struct failed {};
34 
35 template <class Model>
36 struct requirement<failed ************ Model::************>
37 {
failedboost::concepts::requirement38     static void failed() { ((Model*)0)->~Model(); }
39 };
40 
41 # ifdef BOOST_OLD_CONCEPT_SUPPORT
42 
43 template <class Model>
44 struct constraint
45 {
failedboost::concepts::constraint46     static void failed() { ((Model*)0)->constraints(); }
47 };
48 
49 template <class Model>
50 struct requirement_<void(*)(Model)>
51   : mpl::if_<
52         concepts::not_satisfied<Model>
53       , constraint<Model>
54       , requirement<failed ************ Model::************>
55     >::type
56 {};
57 
58 # else
59 
60 // For GCC-2.x, these can't have exactly the same name
61 template <class Model>
62 struct requirement_<void(*)(Model)>
63     : requirement<failed ************ Model::************>
64 {};
65 
66 # endif
67 
68 #  define BOOST_CONCEPT_ASSERT_FN( ModelFnPtr )             \
69     typedef ::boost::concepts::detail::instantiate<          \
70     &::boost::concepts::requirement_<ModelFnPtr>::failed>    \
71       BOOST_PP_CAT(boost_concept_check,__LINE__)
72 
73 }}
74 
75 #endif // BOOST_CONCEPT_DETAIL_GENERAL_DWA2006429_HPP
76