Time zone confusion and implementation hints

[Paul Eggert]

On 07/02/10 07:18, Yves Goergen wrote:

> When a zone defines that a rule set is valid until before 1990 Sep 3 at
> 2:00w or 2:00s, how exactly am I supposed to find out when that is?

You use the rules that were in effect just before the change.
It wouldn't make sense any other way, surely.

> I don't
> understand the cryptic original code (C) of the tz distribution.

Hey, it's not _that_ cryptic!  But I'm afraid that it's the
canonical version.  (Perhaps you can find an old, doddering
C expert nearby who can explain it to you. :-)