FW: "Etc\GMT" positive and negative

[Alain Petit]

Hi

I found the following in the 'etcetera' file.
This seems to explain why your 'positive' zone translate to a 'negative' offset.

# We use POSIX-style signs in the Zone names and the output abbreviations,
# even though this is the opposite of what many people expect.
# POSIX has positive signs west of Greenwich, but many people expect
# positive signs east of Greenwich.  For example, TZ='Etc/GMT+4' uses
# the abbreviation "GMT+4" and corresponds to 4 hours behind UTC
# (i.e. west of Greenwich) even though many people would expect it to
# mean 4 hours ahead of UTC (i.e. east of Greenwich). 

-Alain

-----Original Message-----
From: Ian Abbott [mailto:abbotti at mev.co.uk] 
Sent: Wednesday, February 02, 2011 7:42 PM
To: tz at lecserver.nci.nih.gov
Cc: exis.rdiaz at iberia.es
Subject: Re: FW: "Etc\GMT" positive and negative

> From: EXIS.Diaz Lopez, Rodrigo [mailto:EXIS.rdiaz at iberia.es] Sent:
> Tuesday, February 01, 2011 12:25 To: tz at elsie.nci.nih.gov Subject:
> "Etc\GMT" positive and negative
>
> Hi:
>
> I think I found a bug with the "Etc\GMT" zones.
>
> If you use a "positive zone" like Etc\GMT+2 for calculate actual
> local time in this zone you obtain. local time for Etc\GMT-2 (¡a
> negative zone!). For instance, its' 5:00 PM (UTC/GMT), so in GMT+2
> zone (Greece) the local time must be 7:00 PM. But, if you use TZ
> Database, you obtain. ¡3:00 PM!
>
> And the opposite for "negative zones".
>
> Is a bit funny. Please, check it.
>
> I found a web page
> (http://www.gsp.com/support/virtual/admin/unix/tz/gmt/) that use tz
> database (I think) and shows this error.
>
> Best regards.
>
> P.S.: It is possible that the problem was with the "codes", because
> in the world there are "GMT+13" and "GMT+14" zones, and these zones
> do not exist in tz database. However, in tz database exists "GMT-13"
> and "GMT-14" zones, that not exist in the real world.

Perhaps this is related to the historical "America not wanting to be
negative" problem that gives us "EST5" being the same as "-0500" in
RFC822 terms?

-- 
-=( Ian Abbott @ MEV Ltd.    E-mail: <abbotti at mev.co.uk>        )=-
-=( Tel: +44 (0)161 477 1898   FAX: +44 (0)161 718 3587         )=-