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
7 # include <boost/mpl/bool.hpp>
8 # include <boost/detail/workaround.hpp>
9 # include <boost/concept/detail/backward_compatibility.hpp>
11 namespace boost { namespace concepts {
16 // Here we implement the metafunction that detects whether a
17 // constraints metafunction exists
19 typedef char (&no)[2];
21 template <class Model, void (Model::*)()>
22 struct wrap_constraints {};
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_(...);
31 template <class Model>
32 inline yes has_constraints_(Model*, wrap_constraints<Model,&Model::constraints>* = 0);
33 inline no has_constraints_(...);
37 // This would be called "detail::has_constraints," but it has a strong
38 // tendency to show up in error messages.
39 template <class Model>
42 BOOST_STATIC_CONSTANT(
44 , value = sizeof( detail::has_constraints_((Model*)0) ) == sizeof(detail::yes) );
45 typedef mpl::bool_<value> type;
48 }} // namespace boost::concepts::detail
50 #endif // BOOST_CONCEPT_DETAIL_HAS_CONSTRAINTS_DWA2006429_HPP