

#ifndef BOOST_MPL_VOID_HPP_INCLUDED

#define BOOST_MPL_VOID_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/void_fwd.hpp>

#include <boost/mpl/bool.hpp>

#include <boost/mpl/aux_/na_spec.hpp>

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

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



BOOST_MPL_AUX_ADL_BARRIER_NAMESPACE_OPEN



//  [JDG Feb-4-2003] made void_ a complete type to allow it to be

//  instantiated so that it can be passed in as an object that can be

//  used to select an overloaded function. Possible use includes signaling

//  a zero arity functor evaluation call.

struct void_ { typedef void_ type; };



BOOST_MPL_AUX_ADL_BARRIER_NAMESPACE_CLOSE



namespace boost { namespace mpl {



template< typename T >

struct is_void_

    : false_

{

#if BOOST_WORKAROUND(BOOST_MSVC, < 1300)

    using false_::value;

#endif

};



template<>

struct is_void_<void_>

    : true_

{

#if BOOST_WORKAROUND(BOOST_MSVC, < 1300)

    using true_::value;

#endif

};



template< typename T >

struct is_not_void_

    : true_

{

#if BOOST_WORKAROUND(BOOST_MSVC, < 1300)

    using true_::value;

#endif

};



template<>

struct is_not_void_<void_>

    : false_

{

#if BOOST_WORKAROUND(BOOST_MSVC, < 1300)

    using false_::value;

#endif

};



BOOST_MPL_AUX_NA_SPEC(1, is_void_)

BOOST_MPL_AUX_NA_SPEC(1, is_not_void_)



}}



#endif // BOOST_MPL_VOID_HPP_INCLUDED

