27 Time library [time]

27.11 Time zones [time.zone]

27.11.7 Class template zoned_­time [time.zone.zonedtime]

27.11.7.1 Overview [time.zone.zonedtime.overview]

namespace std::chrono { template<class Duration, class TimeZonePtr = const time_zone*> class zoned_time { public: using duration = common_type_t<Duration, seconds>; private: TimeZonePtr zone_; // exposition only sys_time<duration> tp_; // exposition only using traits = zoned_traits<TimeZonePtr>; // exposition only public: zoned_time(); zoned_time(const zoned_time&) = default; zoned_time& operator=(const zoned_time&) = default; zoned_time(const sys_time<Duration>& st); explicit zoned_time(TimeZonePtr z); explicit zoned_time(string_view name); template<class Duration2> zoned_time(const zoned_time<Duration2, TimeZonePtr>& zt); zoned_time(TimeZonePtr z, const sys_time<Duration>& st); zoned_time(string_view name, const sys_time<Duration>& st); zoned_time(TimeZonePtr z, const local_time<Duration>& tp); zoned_time(string_view name, const local_time<Duration>& tp); zoned_time(TimeZonePtr z, const local_time<Duration>& tp, choose c); zoned_time(string_view name, const local_time<Duration>& tp, choose c); template<class Duration2, class TimeZonePtr2> zoned_time(TimeZonePtr z, const zoned_time<Duration2, TimeZonePtr2>& zt); template<class Duration2, class TimeZonePtr2> zoned_time(TimeZonePtr z, const zoned_time<Duration2, TimeZonePtr2>& zt, choose); template<class Duration2, class TimeZonePtr2> zoned_time(string_view name, const zoned_time<Duration2, TimeZonePtr2>& zt); template<class Duration2, class TimeZonePtr2> zoned_time(string_view name, const zoned_time<Duration2, TimeZonePtr2>& zt, choose); zoned_time& operator=(const sys_time<Duration>& st); zoned_time& operator=(const local_time<Duration>& ut); operator sys_time<duration>() const; explicit operator local_time<duration>() const; TimeZonePtr get_time_zone() const; local_time<duration> get_local_time() const; sys_time<duration> get_sys_time() const; sys_info get_info() const; }; zoned_time() -> zoned_time<seconds>; template<class Duration> zoned_time(sys_time<Duration>) -> zoned_time<common_type_t<Duration, seconds>>; template<class TimeZonePtrOrName> using time-zone-representation = // exposition only conditional_t<is_convertible_v<TimeZonePtrOrName, string_view>, const time_zone*, remove_cvref_t<TimeZonePtrOrName>>; template<class TimeZonePtrOrName> zoned_time(TimeZonePtrOrName&&) -> zoned_time<seconds, time-zone-representation<TimeZonePtrOrName>>; template<class TimeZonePtrOrName, class Duration> zoned_time(TimeZonePtrOrName&&, sys_time<Duration>) -> zoned_time<common_type_t<Duration, seconds>, time-zone-representation<TimeZonePtrOrName>>; template<class TimeZonePtrOrName, class Duration> zoned_time(TimeZonePtrOrName&&, local_time<Duration>, choose = choose::earliest) -> zoned_time<common_type_t<Duration, seconds>, time-zone-representation<TimeZonePtrOrName>>; template<class Duration, class TimeZonePtrOrName, class TimeZonePtr2> zoned_time(TimeZonePtrOrName&&, zoned_time<Duration, TimeZonePtr2>, choose = choose::earliest) -> zoned_time<common_type_t<Duration, seconds>, time-zone-representation<TimeZonePtrOrName>>; }
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zoned_­time represents a logical pairing of a time_­zone and a time_­point with precision Duration.
zoned_­time<Duration> maintains the invariant that it always refers to a valid time zone and represents a point in time that exists and is not ambiguous in that time zone.
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If Duration is not a specialization of chrono​::​duration, the program is ill-formed.
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Every constructor of zoned_­time that accepts a string_­view as its first parameter does not participate in class template argument deduction ([over.match.class.deduct]).