#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: /cvsroot/boost/boost/boost/mpl/empty_base.hpp,v $

 // $Date: 2004/09/02 15:40:41 $

 // $Revision: 1.4 $

 #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