boost/boost/type_traits/is_reference.hpp

   1
   2 //  (C) Copyright David Abrahams Steve Cleary, Beman Dawes, Howard
   3 //  Hinnant & John Maddock 2000-2002.  Permission to copy, use,
   4 //  modify, sell and distribute this software is granted provided this
   5 //  copyright notice appears in all copies. This software is provided
   6 //  "as is" without express or implied warranty, and with no claim as
   7 //  to its suitability for any purpose.
   8 //
   9 //  See http://www.boost.org for most recent version including documentation.
  10
  11 #ifndef BOOST_TT_IS_REFERENCE_HPP_INCLUDED
  12 #define BOOST_TT_IS_REFERENCE_HPP_INCLUDED
  13
  14 #include "boost/type_traits/config.hpp"
  15
  16 #ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
  17 #   include "boost/type_traits/detail/yes_no_type.hpp"
  18 #   include "boost/type_traits/detail/wrap.hpp"
  19 #endif
  20
  21 #if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) && defined(BOOST_MSVC)
  22 #   include "boost/type_traits/detail/is_function_type_tester.hpp"
  23 #   include "boost/type_traits/detail/false_result.hpp"
  24 #endif
  25
  26 // should be the last #include
  27 #include "boost/type_traits/detail/bool_trait_def.hpp"
  28
  29 namespace boost {
  30
  31 #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
  32
  33 BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_reference,T,false)
  34 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_reference,T&,true)
  35
  36 #if defined(__BORLANDC__)
  37 // these are illegal specialisations; cv-qualifies applied to
  38 // references have no effect according to [8.3.2p1],
  39 // C++ Builder requires them though as it treats cv-qualified
  40 // references as distinct types...
  41 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_reference,T& const,true)
  42 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_reference,T& volatile,true)
  43 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_reference,T& const volatile,true)
  44 #endif
  45
  46 #else
  47
  48 #ifdef BOOST_MSVC
  49 #   pragma warning(push)
  50 #   pragma warning(disable: 4181)
  51 #endif
  52
  53 namespace detail {
  54
  55 using ::boost::type_traits::yes_type;
  56 using ::boost::type_traits::no_type;
  57 using ::boost::type_traits::wrap;
  58
  59 template <class T> T&(* is_reference_helper1(wrap<T>) )(wrap<T>);
  60 char is_reference_helper1(...);
  61
  62 template <class T> no_type is_reference_helper2(T&(*)(wrap<T>));
  63 yes_type is_reference_helper2(...);
  64
  65 template <typename T>
  66 struct is_reference_impl
  67 {
  68     BOOST_STATIC_CONSTANT(
  69         bool, value = sizeof(
  70             ::boost::detail::is_reference_helper2(
  71                 ::boost::detail::is_reference_helper1(::boost::type_traits::wrap<T>()))) == 1
  72         );
  73 };
  74
  75 } // namespace detail
  76
  77 BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_reference,T,::boost::detail::is_reference_impl<T>::value)
  78 BOOST_TT_AUX_BOOL_TRAIT_SPEC1(is_reference,void,false)
  79 #ifndef BOOST_NO_CV_VOID_SPECIALIZATIONS
  80 BOOST_TT_AUX_BOOL_TRAIT_SPEC1(is_reference,void const,false)
  81 BOOST_TT_AUX_BOOL_TRAIT_SPEC1(is_reference,void volatile,false)
  82 BOOST_TT_AUX_BOOL_TRAIT_SPEC1(is_reference,void const volatile,false)
  83 #endif
  84
  85 #ifdef BOOST_MSVC
  86 #   pragma warning(pop)
  87 #endif
  88
  89 #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
  90
  91 } // namespace boost
  92
  93 #include "boost/type_traits/detail/bool_trait_undef.hpp"
  94
  95 #endif // BOOST_TT_IS_REFERENCE_HPP_INCLUDED