prevalence of "right" time zones without timegm()?

Andrew Bartlett abartlet at
Thu Jul 7 19:58:10 EDT 2011

On Thu, 2011-07-07 at 19:36 -0400, Tom Yu wrote:
> Andrew Bartlett <abartlet at> writes:
> > Perhaps I wasn't clear.  Microsoft prepared some default Fedora Linux
> > installations for us.  They selected the west coat US timezone (as you
> > would).  This was not some special setup, it was a default setup.  That
> > is why I'm so concerned about the idea of punting this as 'user error'. 
> Ah.  Thank you for that information.  This needs further
> investigation.  Red Hat people, do you have any insight as to why the
> Fedora installer might do something like that?

Well, it wasn't an installer issue, at the time, I reproduced it locally
by setting a Seattle time-zone.  Perhaps there was a bug in the Fedora
tz db at that particular moment, or some other quirk.  

> I wouldn't characterize my proposal as punting this as "user error";
> My proposal should make a definite improvement over the current
> situation on systems where timegm() is natively available.  That's one
> of the reasons I'm trying to get more information on how often "right"
> time zones get configured (whether by explicit user action or by OS
> installer behavior) on systems that lack a native timegm().

I'm still incredibly wary of having any behaviour that breaks things so
subtly depending on a timezone setting.

If you must try and use the system function (meaning that the internal
implementation is almost never tested) always use a matching pair of
either internal or system timegm() and gmtime() functions. 

Andrew Bartlett

Andrew Bartlett <abartlet at>

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