[tz] User time zones

John Haxby john.haxby at oracle.com
Thu Dec 8 15:09:58 UTC 2011

On 08/12/11 14:39, Steven Abner wrote:
> For MST, let's first state that yes there are 8 zones that have conflicts.
> In the case of MST, there is no conflict. If let's say Denver in July did
> output a timestamp string of 12:00 MST, then it is a sure thing that
> the computer output the correct conversion to MST, or if it didn't, a sure thing
> that the use of strftime() and/or mktime() has a bug in that system

There's an additional problem.   People mis-write times.   I've missed
meeting because the meeting organiser said it was "9am PST" but since
that was shortly after the clocks changed in spring I was out by an
hour.   Well, I would have been except that I asked for clarification
and told it was "standard time" which the meeting organiser took to be
PST in winter and PDT in summer.    Some years later I had the same
problem with another person who assumed that GMT simply meant UK local
time which, of course, it does not.

Not only do you have to guess at what the abbreviation might mean, you
also have to guess at what was in the mind of the person writing the
time, regardless of the locale they are from and the locale whose time
they are writing down.   It's hard enough for humans to get this right
with all the context that they have, it's impossible for software to get
it right.


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