29 Time library [time]

29.7 Clocks [time.clock]

29.7.10 time_point conversions [time.clock.cast]

29.7.10.3 Conversions between system_clock and utc_clock [time.clock.cast.sys.utc]

template<> struct clock_time_conversion<utc_clock, system_clock> { template<class Duration> utc_time<common_type_t<Duration, seconds>> operator()(const sys_time<Duration>& t) const; };
template<class Duration> utc_time<common_type_t<Duration, seconds>> operator()(const sys_time<Duration>& t) const;
Returns: utc_clock​::​from_sys(t).
template<> struct clock_time_conversion<system_clock, utc_clock> { template<class Duration> sys_time<common_type_t<Duration, seconds>> operator()(const utc_time<Duration>& t) const; };
template<class Duration> sys_time<common_type_t<Duration, seconds>> operator()(const utc_time<Duration>& t) const;
Returns: utc_clock​::​to_sys(t).