ext-boost/boost/mpl/aux_/msvc_is_class.hpp
2014-12-07 23:50:51 +01:00

58 lines
1.5 KiB
C++

#ifndef BOOST_MPL_AUX_MSVC_IS_CLASS_HPP_INCLUDED
#define BOOST_MPL_AUX_MSVC_IS_CLASS_HPP_INCLUDED
// Copyright Aleksey Gurtovoy 2002-2004
//
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/libs/mpl for documentation.
// $Id$
// $Date$
// $Revision$
#include <boost/mpl/if.hpp>
#include <boost/mpl/bool.hpp>
#include <boost/mpl/aux_/type_wrapper.hpp>
#include <boost/mpl/aux_/yes_no.hpp>
#include <boost/type_traits/is_reference.hpp>
namespace boost { namespace mpl { namespace aux {
template< typename T > struct is_class_helper
{
typedef int (T::* type)();
};
// MSVC 6.x-specific lightweight 'is_class' implementation;
// Distinguishing feature: does not instantiate the type being tested.
template< typename T >
struct msvc_is_class_impl
{
template< typename U>
static yes_tag test(type_wrapper<U>*, /*typename*/ is_class_helper<U>::type = 0);
static no_tag test(void const volatile*, ...);
enum { value = sizeof(test((type_wrapper<T>*)0)) == sizeof(yes_tag) };
typedef bool_<value> type;
};
// agurt, 17/sep/04: have to check for 'is_reference' upfront to avoid ICEs in
// complex metaprograms
template< typename T >
struct msvc_is_class
: if_<
is_reference<T>
, false_
, msvc_is_class_impl<T>
>::type
{
};
}}}
#endif // BOOST_MPL_AUX_MSVC_IS_CLASS_HPP_INCLUDED