boost/type_traits/is_union.hpp

   1
   2 //  (C) Copyright Dave Abrahams, Steve Cleary, Beman Dawes, Howard
   3 //  Hinnant & John Maddock 2000.
   4 //  Use, modification and distribution are subject to the Boost Software License,
   5 //  Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   6 //  http://www.boost.org/LICENSE_1_0.txt).
   7 //
   8 //  See http://www.boost.org/libs/type_traits for most recent version including documentation.
   9
  10
  11 #ifndef BOOST_TT_IS_UNION_HPP_INCLUDED
  12 #define BOOST_TT_IS_UNION_HPP_INCLUDED
  13
  14 #include <boost/type_traits/remove_cv.hpp>
  15 #include <boost/type_traits/config.hpp>
  16 #include <boost/type_traits/intrinsics.hpp>
  17
  18 // should be the last #include
  19 #include <boost/type_traits/detail/bool_trait_def.hpp>
  20
  21 namespace boost {
  22
  23 namespace detail {
  24 #ifndef __GNUC__
  25 template <typename T> struct is_union_impl
  26 {
  27    typedef typename remove_cv<T>::type cvt;
  28 #ifdef BOOST_IS_UNION
  29    BOOST_STATIC_CONSTANT(bool, value = BOOST_IS_UNION(cvt));
  30 #else
  31    BOOST_STATIC_CONSTANT(bool, value = false);
  32 #endif
  33 };
  34 #else
  35 //
  36 // using remove_cv here generates a whole load of needless
  37 // warnings with gcc, since it doesn't do any good with gcc
  38 // in any case (at least at present), just remove it:
  39 //
  40 template <typename T> struct is_union_impl
  41 {
  42 #ifdef BOOST_IS_UNION
  43    BOOST_STATIC_CONSTANT(bool, value = BOOST_IS_UNION(T));
  44 #else
  45    BOOST_STATIC_CONSTANT(bool, value = false);
  46 #endif
  47 };
  48 #endif
  49 } // namespace detail
  50
  51 BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_union,T,::boost::detail::is_union_impl<T>::value)
  52
  53 } // namespace boost
  54
  55 #include <boost/type_traits/detail/bool_trait_undef.hpp>
  56
  57 #endif // BOOST_TT_IS_UNION_HPP_INCLUDED