source: NonGTP/Boost/boost/mpl/aux_/msvc_is_class.hpp @ 857

Revision 857, 1.6 KB checked in by igarcia, 19 years ago (diff)
Line 
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// $Source: /cvsroot/boost/boost/boost/mpl/aux_/msvc_is_class.hpp,v $
14// $Date: 2004/09/28 13:56:59 $
15// $Revision: 1.4 $
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
24namespace boost { namespace mpl { namespace aux {
25
26template< 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.
33template< typename T >
34struct 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
46template< typename T >
47struct 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
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