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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 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/mpl/bool.hpp>
+# include <boost/detail/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 mpl::bool_<value> type;
+};
+
+}} // namespace boost::concepts::detail
+
+#endif // BOOST_CONCEPT_DETAIL_HAS_CONSTRAINTS_DWA2006429_HPP