| Brian Silverman | bca6d25 | 2018-08-04 23:36:16 -0700 | [diff] [blame^] | 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_CHECK_HAS_CONSTRAINTS_DWA2006429_HPP |
| 5 | # define BOOST_CONCEPT_CHECK_HAS_CONSTRAINTS_DWA2006429_HPP |
| 6 | |
| 7 | namespace boost { namespace concept_checking { |
| 8 | |
| 9 | // Here we implement the "metafunction" that detects whether a |
| 10 | // constraints metafunction exists |
| 11 | typedef char yes; |
| 12 | typedef char (&no)[2]; |
| 13 | |
| 14 | template <class Model, void (Model::*)()> |
| 15 | struct wrap_constraints {}; |
| 16 | |
| 17 | template <class Model> |
| 18 | inline yes has_constraints_(Model*, wrap_constraints<Model,&Model::constraints>* = 0); |
| 19 | inline no has_constraints_(...); |
| 20 | |
| 21 | template <class Model> |
| 22 | struct has_constraints |
| 23 | { |
| 24 | BOOST_STATIC_CONSTANT( |
| 25 | bool |
| 26 | , value = sizeof( concept_checking::has_constraints_((Model*)0) ) == 1 ); |
| 27 | }; |
| 28 | |
| 29 | }} // namespace boost::concept_checking |
| 30 | |
| 31 | #endif // BOOST_CONCEPT_CHECK_HAS_CONSTRAINTS_DWA2006429_HPP |