Rules that Don't Exist

Ken Pizzini tz_ at
Fri Nov 23 21:41:04 UTC 2007

On Fri, Nov 23, 2007 at 12:34:10PM -0600, Bill Seymour wrote:
> What happens when switching to a named rule, but no such rule exists?
> The Europe/Zurich example in zic.8.txt has an example of that (switches
> to Swiss rules in 1894, but there are no Swiss rules before 1940), but
> doesn't say what to do.

The important thing to remember is that the rules specify *transitions*.
If there is no transition, then nothing changes, so the fact that the
Swiss rules lack any transitions between 1894 and 1940 means that
Europe/Zurich keeps their clocks at the same offset from UTC (or rather,
given the time frame involved, from GMT) during the interval
in question.

		--Ken Pizzini

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