On 2024-03-06 07:39, James Cloos via tz wrote:
(I must say it was a bit anoying that the library kept the original definition of EST5EDT et alia rathar than moving with the legislation. But only a bit.)
So Openwrt uses pre-2007 US daylight saving rules for TZ='EST5EDT'? That's puzzling. I thought Openwrt is based on musl, which ignores DST for that TZ setting (a behavior that POSIX allows). I'm a bit curious as to what's going on there.
So I have to use EST5EDT,M3.2.0/2:00:00,M11.1.0/2:00:00 for the timezone. (The explicit /2:00:00 might be avoidable, but the use of self documenting data can be beneficial.)
For a fully self-documented TZ setting you could use this: <EST>+05:00:00<EDT>+04:00:00,M3.2.0/+02:00:00,M11.1.0/+02:00:00 However, this sort of thing tends to be error-prone; e.g., suppose I forgot a colon? 'zic' attempts to generate the shortest equivalent TZ setting. On my machine /usr/share/zoneinfo/America/New_York ends with this equivalent: EST5EDT,M3.2.0,M11.1.0 which I find more readable. I'm used to TZ strings, though, so that colors my opinion.