boost/boost/type_traits/is_class.hpp

   1 //  (C) Copyright Dave Abrahams, Steve Cleary, Beman Dawes, Howard
   2 //  Hinnant & John Maddock 2000-2002.  Permission to copy, use,
   3 //  modify, sell and distribute this software is granted provided this
   4 //  copyright notice appears in all copies. This software is provided
   5 //  "as is" without express or implied warranty, and with no claim as
   6 //  to its suitability for any purpose.
   7 //
   8 //  See http://www.boost.org for most recent version including documentation.
   9
  10 #ifndef BOOST_TT_IS_CLASS_HPP_INCLUDED
  11 #define BOOST_TT_IS_CLASS_HPP_INCLUDED
  12
  13 #include "boost/type_traits/config.hpp"
  14
  15 #ifdef BOOST_TT_HAS_CONFORMING_IS_CLASS_IMPLEMENTATION
  16 #   include "boost/type_traits/detail/yes_no_type.hpp"
  17 #else
  18 #   include "boost/type_traits/is_union.hpp"
  19 #   include "boost/type_traits/is_scalar.hpp"
  20 #   include "boost/type_traits/is_array.hpp"
  21 #   include "boost/type_traits/is_reference.hpp"
  22 #   include "boost/type_traits/is_void.hpp"
  23 #   include "boost/type_traits/is_function.hpp"
  24 #   include "boost/type_traits/detail/ice_and.hpp"
  25 #   include "boost/type_traits/detail/ice_not.hpp"
  26 #endif
  27
  28 // should be the last #include
  29 #include "boost/type_traits/detail/bool_trait_def.hpp"
  30
  31 namespace boost {
  32
  33 namespace detail {
  34
  35 #ifdef BOOST_TT_HAS_CONFORMING_IS_CLASS_IMPLEMENTATION
  36
  37 // This is actually the conforming implementation which works with
  38 // abstract classes.  However, enough compilers have trouble with
  39 // it that most will use the one in
  40 // boost/type_traits/object_traits.hpp. This implementation
  41 // actually works with VC7.0, but other interactions seem to fail
  42 // when we use it.
  43
  44 // is_class<> metafunction due to Paul Mensonides
  45 // (leavings@attbi.com). For more details:
  46 // http://groups.google.com/groups?hl=en&selm=000001c1cc83%24e154d5e0%247772e50c%40c161550a&rnum=1
  47
  48 template <typename T>
  49 struct is_class_impl
  50 {
  51     template <class U> static ::boost::type_traits::yes_type is_class_tester(void(U::*)(void));
  52     template <class U> static ::boost::type_traits::no_type is_class_tester(...);
  53
  54     BOOST_STATIC_CONSTANT(bool, value =
  55         sizeof(is_class_tester<T>(0)) == sizeof(::boost::type_traits::yes_type)
  56         );
  57 };
  58
  59 #else
  60
  61 template <typename T>
  62 struct is_class_impl
  63 {
  64 #   ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
  65     BOOST_STATIC_CONSTANT(bool, value =
  66     (::boost::type_traits::ice_and<
  67         ::boost::type_traits::ice_not< ::boost::is_union<T>::value >::value,
  68         ::boost::type_traits::ice_not< ::boost::is_scalar<T>::value >::value,
  69         ::boost::type_traits::ice_not< ::boost::is_array<T>::value >::value,
  70         ::boost::type_traits::ice_not< ::boost::is_reference<T>::value>::value,
  71         ::boost::type_traits::ice_not< ::boost::is_void<T>::value >::value,
  72         ::boost::type_traits::ice_not< ::boost::is_function<T>::value >::value
  73         >::value));
  74 #   else
  75     BOOST_STATIC_CONSTANT(bool, value =
  76     (::boost::type_traits::ice_and<
  77         ::boost::type_traits::ice_not< ::boost::is_union<T>::value >::value,
  78         ::boost::type_traits::ice_not< ::boost::is_scalar<T>::value >::value,
  79         ::boost::type_traits::ice_not< ::boost::is_array<T>::value >::value,
  80         ::boost::type_traits::ice_not< ::boost::is_reference<T>::value>::value,
  81         ::boost::type_traits::ice_not< ::boost::is_void<T>::value >::value
  82         >::value));
  83 #   endif
  84 };
  85
  86 # endif // BOOST_TT_HAS_CONFORMING_IS_CLASS_IMPLEMENTATION
  87
  88 } // namespace detail
  89
  90 BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_class,T,::boost::detail::is_class_impl<T>::value)
  91
  92 } // namespace boost
  93
  94 #include "boost/type_traits/detail/bool_trait_undef.hpp"
  95
  96 #endif // BOOST_TT_IS_CLASS_HPP_INCLUDED