ceph/src/boost/libs/mpl/include/boost/mpl/aux_/msvc_is_class.hpp

   1
   2 #ifndef BOOST_MPL_AUX_MSVC_IS_CLASS_HPP_INCLUDED
   3 #define BOOST_MPL_AUX_MSVC_IS_CLASS_HPP_INCLUDED
   4
   5 // Copyright Aleksey Gurtovoy 2002-2004
   6 //
   7 // Distributed under the Boost Software License, Version 1.0.
   8 // (See accompanying file LICENSE_1_0.txt or copy at
   9 // http://www.boost.org/LICENSE_1_0.txt)
  10 //
  11 // See http://www.boost.org/libs/mpl for documentation.
  12
  13 // $Id$
  14 // $Date$
  15 // $Revision$
  16
  17 #include <boost/mpl/if.hpp>
  18 #include <boost/mpl/bool.hpp>
  19 #include <boost/mpl/aux_/type_wrapper.hpp>
  20 #include <boost/mpl/aux_/yes_no.hpp>
  21
  22 #include <boost/type_traits/is_reference.hpp>
  23
  24 namespace boost { namespace mpl { namespace aux {
  25
  26 template< typename T > struct is_class_helper
  27 {
  28     typedef int (T::* type)();
  29 };
  30
  31 // MSVC 6.x-specific lightweight 'is_class' implementation;
  32 // Distinguishing feature: does not instantiate the type being tested.
  33 template< typename T >
  34 struct msvc_is_class_impl
  35 {
  36     template< typename U>
  37     static yes_tag  test(type_wrapper<U>*, /*typename*/ is_class_helper<U>::type = 0);
  38     static no_tag   test(void const volatile*, ...);
  39
  40     enum { value = sizeof(test((type_wrapper<T>*)0)) == sizeof(yes_tag) };
  41     typedef bool_<value> type;
  42 };
  43
  44 // agurt, 17/sep/04: have to check for 'is_reference' upfront to avoid ICEs in
  45 // complex metaprograms
  46 template< typename T >
  47 struct msvc_is_class
  48     : if_<
  49           is_reference<T>
  50         , false_
  51         , msvc_is_class_impl<T>
  52         >::type
  53 {
  54 };
  55
  56 }}}
  57
  58 #endif // BOOST_MPL_AUX_MSVC_IS_CLASS_HPP_INCLUDED