27 Time library [time]

27.7 Clocks [time.clock]

27.7.10 time_­point conversions [time.clock.cast]

27.7.10.5 Conversions between utc_­clock and other clocks [time.clock.cast.utc]

template<class SourceClock> struct clock_time_conversion<utc_clock, SourceClock> { template<class Duration> auto operator()(const time_point<SourceClock, Duration>& t) const -> decltype(SourceClock::to_utc(t)); };
template<class Duration> auto operator()(const time_point<SourceClock, Duration>& t) const -> decltype(SourceClock::to_utc(t));
Constraints: SourceClock​::​to_­utc(t) is well-formed.
Mandates: SourceClock​::​to_­utc(t) returns a utc_­time<Duration2> for some type Duration2 ([time.point.general]).
Returns: SourceClock​::​to_­utc(t).
template<class DestClock> struct clock_time_conversion<DestClock, utc_clock> { template<class Duration> auto operator()(const utc_time<Duration>& t) const -> decltype(DestClock::from_utc(t)); };
template<class Duration> auto operator()(const utc_time<Duration>& t) const -> decltype(DestClock::from_utc(t));
Constraints: DestClock​::​from_­utc(t) is well-formed.
Mandates: DestClock​::​from_­utc(t) returns a time_­point<DestClock, Duration2> for some type Duration2 ([time.point.general]).
Returns: DestClock​::​from_­utc(t).