[time-nuts] Leap Quirks

[Magnus Danielson]

M. Warner Losh skrev:
> In message: <m3mye8qen3.fsf at lugabout.jhcloos.org>
>             James Cloos <cloos at jhcloos.com> writes:
> : >>>>> "Warner" == M Warner Losh <imp at bsdimp.com> writes:
> : 
> : Jim> By which sequence?
> : 
> : Warner> The sequence where midnight % 86400 isn't 0.
> : 
> : MY appologies, but that isn't narrowing it for me.  POSIX only cares
> : about POSIX midnight, not UTC midnight, so the fact that it was already
> : past PODIX midnight when the leap second and UTC midnight happened is
> : irrelevant to POSIX.
> 
> posix midnight and utc midnight are the same things.  You had said
> that the system time was returned as ....24 at UTC 2009-01-01
> 00:00:00, which isn't posixly correct.

Um... no. That's the hacked POSIX interpretation, not the POSIX standard.

We have at least three POSIX interpretations here.

One which has UTC rubber seconds from 1970 to 1972 and from then true SI 
seconds from 1972.
One which has true SI seconds from 1970.
One which has UTC tracking in pieces and is slid "sideways" to make 
midnight match UTC midnight.

The two first ones is interpretations of POSIX over UTC variations. The 
third one is a hack of POSIX to make it kind of work anyway with NTP. 
Only with the third interpretation POSIX midnight and UTC midnight is 
the same.

Now, which of them is "right"?

Cheers,
Magnus