[LEAPSECS] Crunching Bulletin B numbers (POSIX time)

Tony Finch dot at dotat.at
Wed Feb 23 05:07:40 EST 2011

On Tue, 22 Feb 2011, Keith Winstein wrote:


You made several good points though I have some minor niggles.

> Calculations further in the future, though, still won't be "functional" and

> will change their results when new leap seconds are loaded into the zoneinfo

> files. This seems to be to be an artifact of having intercalary seconds in the

> local time scale at all -- whether they are in time_t (as in POSIX) or in the

> conversion to localtime (as here), it seems to be the same problem either way.

It isn't that bad if the intercalation is predictable. Even better if it
can be hard-coded, as in arithmetic calendars.

Note that POSIX time has no intercalation: it is a version of traditional
universal time. Specifying it in terms of UTC is mostly a red herring,
especially since POSIX doesn't specify how time_t is synchronized.

f.anthony.n.finch <dot at dotat.at> http://dotat.at/
Biscay: Mainly westerly or southwesterly 3 or 4, occasionally 5 at first.
Rough becoming moderate in southeast. Rain or drizzle, fog patches. Moderate,
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