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// Copyright David Abrahams 2006. Distributed under the Boost
// Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at

# 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_(...);
  template <class Model>
  inline yes has_constraints_(Model*, wrap_constraints<Model,&Model::constraints>* = 0);
  inline no has_constraints_(...);

// 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
      , value = sizeof( detail::has_constraints_((Model*)0) ) == sizeof(detail::yes) );
    typedef boost::integral_constant<bool, value> type;

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