[tz] Terminology mismatch in tzcode file format manpage / header

Andrew Paprocki andrew at ishiboo.com
Fri May 18 03:22:20 UTC 2012

On Thu, May 17, 2012 at 9:52 PM, Steve Allen <sla at ucolick.org> wrote:
> It seems imprudent to change the name of the functions in the tzcode
> if in three years the name of the broadcast time scale might change
> to something other than UTC.

> Except that the implementation of zoneinfo is based on the POSIX
> notion of UTC, and that is incongruent with the ITU-R notion of UTC.

As you've pointed out, zoneinfo is based on the POSIX Epoch
definition, so I don't see why ITU-R proceedings have a bearing on
what I was proposing. There are no "functions" in tzcode which would
change name. The only thing that would change name is the struct
member tzh_ttisgmtcnt, which represents "UTC/local indicators, each
stored as a one-byte value; they tell whether the transition times
associated with local time types were specified as UTC or local time".

As ado pointed out in 2007:
"This is indeed historical; the tzh_tisgmtcnt and tzh_ttisstdcnt
header fields (and associated variables) were introduced in 1995 to
allow European time zones to be used as time zone templates, and the
software had to be set up to handle older files from which the
information was absent (and in which the header fields were zero)."

These values have been identical for ages, so I'm suggesting just
naming the field to match its definition as an easy win to avoid
confusion. It does not actually have any bearing on the interpretation
of the data.


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