Chris@16: 
Chris@16: #ifndef BOOST_MPL_VOID_HPP_INCLUDED
Chris@16: #define BOOST_MPL_VOID_HPP_INCLUDED
Chris@16: 
Chris@16: // Copyright Aleksey Gurtovoy 2001-2004
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. 
Chris@16: // (See accompanying file LICENSE_1_0.txt or copy at 
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: // See http://www.boost.org/libs/mpl for documentation.
Chris@16: 
Chris@101: // $Id$
Chris@101: // $Date$
Chris@101: // $Revision$
Chris@16: 
Chris@16: #include <boost/mpl/void_fwd.hpp>
Chris@16: #include <boost/mpl/bool.hpp>
Chris@16: #include <boost/mpl/aux_/na_spec.hpp>
Chris@16: #include <boost/mpl/aux_/config/msvc.hpp>
Chris@16: #include <boost/mpl/aux_/config/workaround.hpp>
Chris@16: 
Chris@16: BOOST_MPL_AUX_ADL_BARRIER_NAMESPACE_OPEN
Chris@16: 
Chris@16: //  [JDG Feb-4-2003] made void_ a complete type to allow it to be
Chris@16: //  instantiated so that it can be passed in as an object that can be
Chris@16: //  used to select an overloaded function. Possible use includes signaling
Chris@16: //  a zero arity functor evaluation call.
Chris@16: struct void_ { typedef void_ type; };
Chris@16: 
Chris@16: BOOST_MPL_AUX_ADL_BARRIER_NAMESPACE_CLOSE
Chris@16: 
Chris@16: namespace boost { namespace mpl {
Chris@16: 
Chris@16: template< typename T >
Chris@16: struct is_void_
Chris@16:     : false_
Chris@16: {
Chris@16: #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
Chris@16:     using false_::value;
Chris@16: #endif
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct is_void_<void_>
Chris@16:     : true_
Chris@16: {
Chris@16: #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
Chris@16:     using true_::value;
Chris@16: #endif
Chris@16: };
Chris@16: 
Chris@16: template< typename T >
Chris@16: struct is_not_void_
Chris@16:     : true_
Chris@16: {
Chris@16: #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
Chris@16:     using true_::value;
Chris@16: #endif
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct is_not_void_<void_>
Chris@16:     : false_
Chris@16: {
Chris@16: #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
Chris@16:     using false_::value;
Chris@16: #endif
Chris@16: };
Chris@16: 
Chris@16: BOOST_MPL_AUX_NA_SPEC(1, is_void_)
Chris@16: BOOST_MPL_AUX_NA_SPEC(1, is_not_void_)
Chris@16: 
Chris@16: }}
Chris@16: 
Chris@16: #endif // BOOST_MPL_VOID_HPP_INCLUDED