[LEAPSECS] How good could civil timekeeping be?

[Michael Sokolov]

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?


> 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.


> 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.

MS