[LEAPSECS] How good could civil timekeeping be?

M. Warner Losh imp at bsdimp.com
Thu Feb 14 17:51:57 EST 2008

In message: <0802142245.AA26840 at ivan.Harhan.ORG>
msokolov at ivan.Harhan.ORG (Michael Sokolov) writes:

: Poul-Henning Kamp <phk at phk.freebsd.dk> wrote:


: > This is the point where the POSIX people shot us in the feet by

: > ignoring leap-seconds.


: Why care about POSIX at all? Why not use a non-POSIX UNIX system then?

Lots of code cares about many properties that POSIX has.

: > The time_t type, contains the number of SI seconds since 1970-01-01

: > 00:00:00 UTC *ignoring all leapseconds*.


: Dunno about POSIX, but in UNIX-in-4-capitals which predates POSIX,

: time_t does NOT mean what you say. UNIX as opposed to POSIX time_t

: measures the angle by which the hands of a wall clock have rotated since

: since they displayed midnight 1970-01-01 in Greenwich. It is a wall

: clock rotation angle and has absolutely nothing to do with SI seconds or

: physical time interval.

You have just described POSIX time.

: > And down at a hairsbreadth, you cannot by looking at a time_t value,

: > tell the leap second from the second right before it. (In some

: > cases it's the second after, but that's clearly a bug since the

: > leap second is the last second in the preceeding 24 hour UTC period.)


: Rubber seconds solve this problem.

No they don't. Rubber seconds are even more evil than leap seconds.


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