template<typename time_type> 
class second_clock {
public:
  // types
  typedef time_type::date_type          date_type;         
  typedef time_type::time_duration_type time_duration_type;

  // public static functions
  time_type local_time() ;
  time_type universal_time() ;
  template<typename time_zone_type> 
    time_type local_time(boost::shared_ptr< time_zone_type >) ;

  // private static functions
  time_type create_time(::std::tm *) ;
};