msvc_is_class.hpp

Go to the documentation of this file.

 
#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: msvc_is_class.hpp 13472 2017-08-22 07:53:44Z richean $
// $Date: 2017-08-22 09:53:44 +0200 (Di, 22 Aug 2017) $
// $Revision: 13472 $
 
#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