Re: use of TZ by mktime()/strftime()

[Ed Morton]

On 8/10/2022 10:56 AM, Eli Zaretskii wrote:
> > From:arnold@skeeve.com
> > Date: Wed, 10 Aug 2022 08:50:07 -0600
> >
> > Ed Morton<mortoneccc@comcast.net>  wrote:
> >
> > > So in the above setting TZ to EST or UTC worked and specifying IST at
> > > the end of the timestamp worked, but setting TZ to IST failed just like
> > > it does in gawk. Clearly I'm missing something...
> > All of this depends on the underlying C library.  As far as I know
> > there aren't standardized time zone names that work the same
> > everywhere.
> Actually, there are, at least in most practical cases.  But they are
> very few, and you cannot rely on their DST rules to be up to date with
> the current practices; they might on some systems still reflect the
> DST rules of many years ago, or even work according to the rules of
> another country.

FWIW I found some information on "standard" time zones:

The IANA Time Zone Database:

   https://www.iana.org/time-zones
   
https://vdc-repo.vmware.com/vmwb-repository/dcr-public/790263bc-bd30-48f1-af12-ed36055d718b/e5f17bfc-ecba-40bf-a04f-376bbb11e811/timezone.html
   https://en.wikipedia.org/wiki/List_of_tz_database_time_zones

The ISO 8601 standard:

   https://en.wikipedia.org/wiki/ISO_8601
   https://www.iso.org/iso-8601-date-and-time-format.html

Thanks for the feedback all, looks like gawk behaves the same as date 
wrt TZ environment values so there's no gawk issue.

    Ed.