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_HAS_CONSTRAINTS_DWA2006429_HPP
5# define BOOST_CONCEPT_DETAIL_HAS_CONSTRAINTS_DWA2006429_HPP
6
7# include <boost/type_traits/integral_constant.hpp>
8# include <boost/config/workaround.hpp>
9# include <boost/concept/detail/backward_compatibility.hpp>
10
11namespace boost { namespace concepts {
12
13namespace detail
14{
15
16// Here we implement the metafunction that detects whether a
17// constraints metafunction exists
18 typedef char yes;
19 typedef char (&no)[2];
20
21 template <class Model, void (Model::*)()>
22 struct wrap_constraints {};
23
24#if BOOST_WORKAROUND(__SUNPRO_CC, <= 0x580) || defined(__CUDACC__)
25 // Work around the following bogus error in Sun Studio 11, by
26 // turning off the has_constraints function entirely:
27 // Error: complex expression not allowed in dependent template
28 // argument expression
29 inline no has_constraints_(...);
30#else
31 template <class Model>
32 inline yes has_constraints_(Model*, wrap_constraints<Model,&Model::constraints>* = 0);
33 inline no has_constraints_(...);
34#endif
35}
36
37// This would be called "detail::has_constraints," but it has a strong
38// tendency to show up in error messages.
39template <class Model>
40struct not_satisfied
41{
42 BOOST_STATIC_CONSTANT(
43 bool
44 , value = sizeof( detail::has_constraints_((Model*)0) ) == sizeof(detail::yes) );
45 typedef boost::integral_constant<bool, value> type;
46};
47
48}} // namespace boost::concepts::detail
49
50#endif // BOOST_CONCEPT_DETAIL_HAS_CONSTRAINTS_DWA2006429_HPP
51

source code of include/boost/concept/detail/has_constraints.hpp