// Copyright David Abrahams 2006. Distributed under the Boost
// Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#ifndef BOOST_CONCEPT_DETAIL_HAS_CONSTRAINTS_DWA2006429_HPP
# define BOOST_CONCEPT_DETAIL_HAS_CONSTRAINTS_DWA2006429_HPP

# include <boost/type_traits/integral_constant.hpp>
# include <boost/config/workaround.hpp>
# include <boost/concept/detail/backward_compatibility.hpp>

namespace boost {
namespace concepts {

namespace detail {

// Here we implement the metafunction that detects whether a
// constraints metafunction exists
typedef char yes;
typedef
char (&no)[2];

template <class Model, void (Model::*)()>
struct wrap_constraints {};

#if BOOST_WORKAROUND(__SUNPRO_CC, <= 0x580) || defined(__CUDACC__)
// Work around the following bogus error in Sun Studio 11, by
// turning off the has_constraints function entirely:
//    Error: complex expression not allowed in dependent template
//    argument expression
inline no
has_constraints_(...);
#else
template <class Model>
inline yes
has_constraints_(Model*, wrap_constraints<Model,&Model::constraints>* = 0);
inline no
has_constraints_(...);
#endif
}

// This would be called "detail::has_constraints," but it has a strong
// tendency to show up in error messages.
template <class Model>
struct not_satisfied
{
    BOOST_STATIC_CONSTANT(
        bool
    , value = sizeof( detail::has_constraints_((Model*)0) ) == sizeof(detail::yes) );
    typedef boost::integral_constant<bool, value> type;
};

}
} // namespace boost::concepts::detail

#endif // BOOST_CONCEPT_DETAIL_HAS_CONSTRAINTS_DWA2006429_HPP
