[LEAPSECS] Crunching Bulletin B numbers (POSIX time)

[Poul-Henning Kamp]

In message <20110221100216.GA9800 at davros.org>, "Clive D.W. Feather" writes:

>Paul Sheer said:



>> These systems don't care whether the event really did happen at

>> 12:34:56pm nor whether the clock was a few minutes slow that day.

>> 

>> But they DO care that they are talking about the SAME event!!!

>

>In which case they will have some arrangement to synchronize their clocks.


You are missing the point.

If the isolated system creates a file and timestamps it with a time_t
value of FOO, that translates to a given UTC instant YYYY-MM-DD/HH:MM:SS

The same numeric time_t must translate to the same UTC instant on an
other POSIX system, connected or otherwise.

It doesn't matter if they agree when this instant happened, but the
*representation* must be the same.

That is why, we cannot have some POSIX systems inserting leap-seconds in
to time_t and some POSIX systems not doing so.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.