[time.zone.timezone] (original) (raw)

30.11.5.1 Overview [time.zone.overview]

namespace std::chrono { class time_zone { public: time_zone(time_zone&&) = default; time_zone& operator=(time_zone&&) = default; string_view name() const noexcept;template<class Duration> sys_info get_info(const sys_time<Duration>& st) const;template<class Duration> local_info get_info(const local_time<Duration>& tp) const;template<class Duration> sys_time<common_type_t<Duration, seconds>> to_sys(const local_time<Duration>& tp) const;template<class Duration> sys_time<common_type_t<Duration, seconds>> to_sys(const local_time<Duration>& tp, choose z) const;template<class Duration> local_time<common_type_t<Duration, seconds>> to_local(const sys_time<Duration>& tp) const;};}

A time_zone represents all time zone transitions for a specific geographic area.

time_zone construction is unspecified, and performed as part of database initialization.

[Note 1:

const time_zone objects can be accessed via functions such as locate_zone.

— _end note_]

30.11.5.2 Member functions [time.zone.members]

string_view name() const noexcept;

Returns: The name of the time_zone.

[Example 1:

"America/New_York".

— _end example_]

template<class Duration> sys_info get_info(const sys_time<Duration>& st) const;

Returns: A sys_info i for whichst is in the range [i.begin, i.end).

template<class Duration> local_info get_info(const local_time<Duration>& tp) const;

Returns: A local_info for tp.

template<class Duration> sys_time<common_type_t<Duration, seconds>> to_sys(const local_time<Duration>& tp) const;

Returns: A sys_time that is at least as fine as seconds, and will be finer if the argument tp has finer precision.

This sys_time is the UTC equivalent of tpaccording to the rules of this time_zone.

Throws: If the conversion from tp to a sys_time is ambiguous, throws ambiguous_local_time.

If the tp represents a non-existent time between two UTC time_points, throws nonexistent_local_time.

template<class Duration> sys_time<common_type_t<Duration, seconds>> to_sys(const local_time<Duration>& tp, choose z) const;

Returns: A sys_time that is at least as fine as seconds, and will be finer if the argument tp has finer precision.

This sys_time is the UTC equivalent of tpaccording to the rules of this time_zone.

If the conversion from tp to a sys_time is ambiguous, returns the earlier sys_time if z == choose​::​earliest, and returns the later sys_time if z == choose​::​latest.

If the tp represents a non-existent time between two UTC time_points, then the two UTC time_points will be the same, and that UTC time_point will be returned.

template<class Duration> local_time<common_type_t<Duration, seconds>> to_local(const sys_time<Duration>& tp) const;

Returns: The local_time associated with tp and this time_zone.