// Copyright (C) 2003, Fernando Luis Cacciola Carballal.

 // Copyright (C) 2007, Anthony Williams

 // Copyright (C) 2007, Steven Watanabe, Richard Smith

 //

 // 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/lib/optional/ for documentation.

 //

 // You are welcome to contact the author at:

 // fernando.cacciola@gmail.com

 //

 #ifndef BOOST_NONE_17SEP2003_HPP

 #define BOOST_NONE_17SEP2003_HPP

 namespace boost

 {

   namespace detail

   {

     class none_helper;

   }

   inline void none(detail::none_helper);

   namespace detail

   {

     class none_helper

     {

     private:

       none_helper( none_helper const& ) {}

       friend void boost::none(none_helper);

     };

   }

   typedef void (*none_t)(detail::none_helper);

   inline void none(detail::none_helper) {}

 }

 #endif