boost/boost/type_traits/is_function.hpp

   1
   2 // Copyright (C) 2000 John Maddock (john_maddock@compuserve.com)
   3 // Copyright (C) 2002 Aleksey Gurtovoy (agurtovoy@meta-comm.com)
   4 //
   5 // Permission to copy and use this software is granted,
   6 // provided this copyright notice appears in all copies.
   7 // Permission to modify the code and to distribute modified code is granted,
   8 // provided this copyright notice appears in all copies, and a notice
   9 // that the code was modified is included with the copyright notice.
  10 //
  11 // This software is provided "as is" without express or implied warranty,
  12 // and with no claim as to its suitability for any purpose.
  13
  14 #ifndef BOOST_TT_IS_FUNCTION_HPP_INCLUDED
  15 #define BOOST_TT_IS_FUNCTION_HPP_INCLUDED
  16
  17 #include "boost/type_traits/is_reference.hpp"
  18 #include "boost/type_traits/detail/false_result.hpp"
  19 #include "boost/config.hpp"
  20
  21 #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
  22 #   include "boost/type_traits/detail/is_function_ptr_helper.hpp"
  23 #else
  24 #   include "boost/type_traits/detail/is_function_ptr_tester.hpp"
  25 #   include "boost/type_traits/detail/yes_no_type.hpp"
  26 #endif
  27
  28 // should be the last #include
  29 #include "boost/type_traits/detail/bool_trait_def.hpp"
  30
  31 // is a type a function?
  32 // Please note that this implementation is unnecessarily complex:
  33 // we could just use !is_convertible<T*, const volatile void*>::value,
  34 // except that some compilers erroneously allow conversions from
  35 // function pointers to void*.
  36
  37 namespace boost {
  38 namespace detail {
  39
  40 #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
  41 template<bool is_ref = true>
  42 struct is_function_chooser
  43     : ::boost::type_traits::false_result
  44 {
  45 };
  46
  47 template <>
  48 struct is_function_chooser<false>
  49 {
  50     template< typename T > struct result_
  51         : ::boost::type_traits::is_function_ptr_helper<T*>
  52     {
  53     };
  54 };
  55
  56 template <typename T>
  57 struct is_function_impl
  58     : is_function_chooser< ::boost::is_reference<T>::value >
  59         ::template result_<T>
  60 {
  61 };
  62
  63 #else
  64
  65 template <typename T>
  66 struct is_function_impl
  67 {
  68     static T* t;
  69     BOOST_STATIC_CONSTANT(
  70         bool, value = sizeof(::boost::type_traits::is_function_ptr_tester(t))
  71         == sizeof(::boost::type_traits::yes_type)
  72         );
  73 };
  74
  75 #endif
  76
  77 } // namespace detail
  78
  79 BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_function,T,::boost::detail::is_function_impl<T>::value)
  80
  81 } // namespace boost
  82
  83 #include "boost/type_traits/detail/bool_trait_undef.hpp"
  84
  85 #endif // BOOST_TT_IS_FUNCTION_HPP_INCLUDED