#ifndef BOOST_MPL_IS_PLACEHOLDER_HPP_INCLUDED #define BOOST_MPL_IS_PLACEHOLDER_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: is_placeholder.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/arg_fwd.hpp> #include <boost/mpl/bool.hpp> #include <boost/mpl/aux_/yes_no.hpp> #include <boost/mpl/aux_/type_wrapper.hpp> #include <boost/mpl/aux_/nttp_decl.hpp> #include <boost/mpl/aux_/config/ctps.hpp> #include <boost/mpl/aux_/config/static_constant.hpp> namespace boost { namespace mpl { #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) template< typename T > struct is_placeholder : bool_<false> { }; template< BOOST_MPL_AUX_NTTP_DECL(int, N) > struct is_placeholder< arg<N> > : bool_<true> { }; #else namespace aux { aux::no_tag is_placeholder_helper(...); template< BOOST_MPL_AUX_NTTP_DECL(int, N) > aux::yes_tag is_placeholder_helper(aux::type_wrapper< arg<N> >*); } // namespace aux template< typename T > struct is_placeholder { static aux::type_wrapper<T>* get(); BOOST_STATIC_CONSTANT(bool, value = sizeof(aux::is_placeholder_helper(get())) == sizeof(aux::yes_tag) ); typedef bool_<value> type; }; #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION }} #endif // BOOST_MPL_IS_PLACEHOLDER_HPP_INCLUDED