#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. // $Id: void.hpp 49267 2008-10-11 06:19:02Z agurtovoy $ // $Date: 2008-10-10 23:19:02 -0700 (Fri, 10 Oct 2008) $ // $Revision: 49267 $ #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