Time Zone Conversions

Helpers for converting supported regional time zones and UTC. More...

Topics
	Time zone conversion helpers

Files
file	time_zone_offset.hpp
	UTC offset arithmetic helpers (UTC <-> local) and TimeZoneStruct offset extraction.
file	time_zone_conversions.hpp
	Helpers for converting supported regional time zones and UTC.

Detailed Description

Helpers for converting supported regional time zones and UTC.

These helpers cover:

• DST-aware European civil time (WET, CET, EET) with the existing rule set,
• DST-aware US civil time (ET, CT),
• fixed-offset trading-oriented zones such as IST, MYT, WIB, WITA, WIT, KZT, TRT, BYT, SGT, ICT, PHT, GST, HKT, JST, and KST,
• generic zone_to_gmt, gmt_to_zone, and convert_time_zone entry points.

The two-argument local-to-UTC conversion helpers keep their legacy best-effort semantics. Use resolve_local_time_ms, zone_to_gmt_ms_strict, or the policy overloads when local civil time can fall into a DST gap or fold. A nonexistent local time has no UTC candidate, while an ambiguous local time has first and second UTC occurrences. UTC-to-local conversion is single-valued; use zone_offset_at_utc / zone_offset_at_utc_ms when the effective offset matters.

Example Usage:

ts_t gmt_ts = time_shield::to_ts(2024, Month::JUN, 21, 12, 0, 0);
ts_t ist_ts = time_shield::gmt_to_ist(gmt_ts);
ts_t myt_ts = time_shield::convert_time_zone(ist_ts, time_shield::IST, time_shield::MYT);