// In header: <boost/unicode/utf_codecs.hpp>


struct utf_locale_transcoder {
  // types
  typedef wchar_t                                                      input_type; 
  typedef char                                                         output_type;
  typedef codecvt_out_converter< input_type, output_type >::max_output max_output; 

  // construct/copy/destruct
  utf_locale_transcoder(std::locale = std::locale(getenv("LANG")));

  // public member functions
  template<typename In, typename Out> Out ltr(In &, In, Out);
  template<typename In, typename Out> Out rtl(In, In &, Out);
  std::locale loc;
};