On 2026-03-07 09:54, Guy Harris wrote:
On Mar 7, 2026, at 9:43 AM, Paul Eggert via tz <tz@iana.org> wrote:
I daresay more apps read TZif via other means than via tzcode and derivatives.
Any idea:
1) how many of them do so because they're using some standard library (e.g., ICU) that doesn't sit atop a tzcode-based C standard library vs. other reasons, such as an application having its own code?
Although I haven't done a survey, I expect it's usually using a library, such as one of those mentioned in <https://data.iana.org/time-zones/tz-link.html#TZif> (by no means a complete list).
2) how many of them do so because the tzcode doesn't provide some capability (e.g., calls to get a list of transitions or to determine when the next transition will be) vs. some other reason?
I expect this is rarer. However, one major API does that sort of thing: the time zone API of C++20 and later <https://en.cppreference.com/w/cpp/chrono.html#Time_zone>. I don't track its implementations. Whatever they are, they can't be based just on tzcode as the tzcode API doesn't support that sort of thing.