

#ifndef BOOST_MPL_EMPTY_BASE_HPP_INCLUDED

#define BOOST_MPL_EMPTY_BASE_HPP_INCLUDED



// Copyright Aleksey Gurtovoy 2001-2004

//

// 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.



// $Source$

// $Date: 2004-09-02 11:41:37 -0400 (Thu, 02 Sep 2004) $

// $Revision: 24874 $



#include <boost/mpl/bool.hpp>

#include <boost/mpl/aux_/config/msvc.hpp>

#include <boost/mpl/aux_/config/workaround.hpp>



#include <boost/type_traits/is_empty.hpp>



// should be always the last #include directive

#include <boost/type_traits/detail/bool_trait_def.hpp>



namespace boost { namespace mpl {



// empty base class, guaranteed to have no members; inheritance from

// 'empty_base' through the 'inherit' metafunction is a no-op - see 

// "mpl/inherit.hpp> header for the details

struct empty_base {};



template< typename T >

struct is_empty_base

    : false_

{

#if BOOST_WORKAROUND(BOOST_MSVC, < 1300)

    using false_::value;

#endif

};



template<>

struct is_empty_base<empty_base>

    : true_

{

#if BOOST_WORKAROUND(BOOST_MSVC, < 1300)

    using true_::value;

#endif

};



}}



namespace boost {

BOOST_TT_AUX_BOOL_TRAIT_SPEC1(is_empty, mpl::empty_base, true)

}



#include <boost/type_traits/detail/bool_trait_undef.hpp>



#endif // BOOST_MPL_EMPTY_BASE_HPP_INCLUDED

