text: // Copyright (C) 2003, Fernando Luis Cacciola Carballal.
  // Copyright (C) 2014 Andrzej Krzemienski.
  //
  // 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/optional for documentation.
  //
  // You are welcome to contact the author at:
  //  fernando_cacciola@hotmail.com
  //
  #ifndef BOOST_NONE_17SEP2003_HPP
  #define BOOST_NONE_17SEP2003_HPP
  
  #include "boost/none_t.hpp"
  
  // NOTE: Borland users have to include this header outside any precompiled headers
  // (bcc<=5.64 cannot include instance data in a precompiled header)
  //  -- * To be verified, now that there's no unnamed namespace
  
  namespace geofeatures_boost {} namespace boost = geofeatures_boost; namespace geofeatures_boost {
  
  #ifdef BOOST_OPTIONAL_USE_OLD_DEFINITION_OF_NONE
  none_t const none = (static_cast<none_t>(0)) ;
  #else
  
  namespace detail { namespace optional_detail {
  
    // the trick here is to make geofeatures_boost::none defined once as a global but in a header file
    template <typename T>
    struct none_instance
    {
      static const T instance;
    };
    
    template <typename T>
    const T none_instance<T>::instance = T(); // global, but because 'tis a template, no cpp file required
  
  } } // namespace detail::optional_detail
  
  
  namespace {
    // TU-local
    const none_t& none = detail::optional_detail::none_instance<none_t>::instance; 
  }
  
  #endif
  
  } // namespace geofeatures_boost
  
  #endif
  
  