boost/concept_check/general.hpp

   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_MSVC_DWA2006429_HPP
   5 # define BOOST_CONCEPT_CHECK_MSVC_DWA2006429_HPP
   6
   7 # ifdef BOOST_OLD_CONCEPT_SUPPORT
   8 #  include <boost/concept_check/has_constraints.hpp>
   9 #  include <boost/mpl/if.hpp>
  10 # endif
  11
  12
  13 // This implementation works on GCC and Comeau, but has actually been
  14 // fairly carefully tuned to work on GCC versions starting with
  15 // gcc-2.95.x.  If you're trying to get an additional compiler to pass
  16 // the tests you might consider breaking out a separate gcc.hpp and
  17 // starting over on the general case.
  18 namespace boost
  19 {
  20   namespace concept_checking
  21   {
  22     template <void(*)()> struct instantiate {};
  23   }
  24
  25   template <class ModelFn> struct concept_check_;
  26
  27   template <class Model>
  28   void concept_check_failed()
  29   {
  30       ((Model*)0)->~Model();
  31   }
  32
  33   template <class Model>
  34   struct concept_check
  35   {
  36       concept_checking::instantiate<concept_check_failed<Model> > x;
  37       enum { instantiate = 1 };
  38   };
  39
  40 # ifdef BOOST_OLD_CONCEPT_SUPPORT
  41
  42   template <class Model>
  43   void constraint_check_failed()
  44   {
  45       ((Model*)0)->constraints();
  46   }
  47
  48   template <class Model>
  49   struct constraint_check
  50   {
  51       concept_checking::instantiate<constraint_check_failed<Model> > x;
  52       enum { instantiate = 1 };
  53   };
  54
  55   template <class Model>
  56   struct concept_check_<void(*)(Model)>
  57     : mpl::if_c<
  58           concept_checking::has_constraints<Model>::value
  59         , constraint_check<Model>
  60         , concept_check<Model>
  61       >::type
  62   {};
  63
  64 # else
  65
  66   template <class Model>
  67   struct concept_check_<void(*)(Model)>
  68     : concept_check<Model>
  69   {};
  70
  71 # endif
  72
  73   // Usage, in class or function context:
  74   //
  75   //     BOOST_CONCEPT_ASSERT((UnaryFunctionConcept<F,bool,int>));
  76 #  define BOOST_CONCEPT_ASSERT( ModelInParens )                             \
  77   enum { BOOST_PP_CAT(boost_concept_check,__LINE__) =                       \
  78          ::boost::concept_check_<void(*) ModelInParens>::instantiate        \
  79   }
  80 }
  81
  82 #endif // BOOST_CONCEPT_CHECK_MSVC_DWA2006429_HPP