27 Time library [time]

27.7 Clocks [time.clock]

27.7.9 time_­point conversions [time.clock.cast]

27.7.9.2 Identity conversions [time.clock.cast.id]

template<class Clock>
struct clock_time_conversion<Clock, Clock> {
  template<class Duration>
    time_point<Clock, Duration>
      operator()(const time_point<Clock, Duration>& t) const;
};

template<>
struct clock_time_conversion<system_clock, system_clock> {
  template<class Duration>
    sys_time<Duration>
      operator()(const sys_time<Duration>& t) const;
};

template<>
struct clock_time_conversion<utc_clock, utc_clock> {
  template<class Duration>
    utc_time<Duration>
      operator()(const utc_time<Duration>& t) const;
};