zoneinfo.txt

ZONEINFO FORMAT
===============

ZONEINFO.xx contains information about all known timezones and locations.
'xx' is a two-letter language code (e.g. 'EN') representing the language
in which the zone information is written (this scheme allows translated
versions of the timezone database to be supported).

(This file is designed to be used by multiple applications, hence it
contains some features not used by Universal Clock.)

The ZONEINFO file is a binary file in OS/2 profile (a.k.a. INI) format. The 
file contents are structured as follows:

1. Any number of application entries representing countries. These are named
   according to two-letter ISO country code (e.g. 'UK', 'US', 'CA', 'DE').

   Each of these application entries contains the following keys:

   - .xx   = The full name of the country in the current language; 'xx'
             is the same language code used in the filename.

             (This naming scheme was originally adopted with an eye to
             allowing multiple languages to be kept in the same ZONEINFO
             file; this idea was abandoned as unworkable, but the naming
             scheme remains.)

   - A list of tzdata timezone names that exist (fully or partially) in
     this country.  Each timezone name is a separate key; these names will
     be cross-referenced to the timezone application entries (described
     below).  Each name should therefore correspond to an existing timezone
     application entry.

     If the timezone name is prefixed with '*', it indicates that, in the
     event that more than one timezone in this country resolves to the same
     TZ string, this particular one should be kept (and not filtered out
     as a duplicate by programs which would otherwise attempt to do so).

     The value of each of the timezone name keys is the (localized and
     translated) name of the corresponding timezone region.  This allows
     the tzdata zone name style (continent/city) to be mapped to the more
     usual country and region style.  (For example, 'America/Montreal'
     maps to 'Canada', 'Eastern'.)


2. Any number of application entries representing timezone names.  These
   use the canonical tzdata names (in the format 'continent/city').

   Each of these application entries contains the following keys:

   - TZ           = The TZ environment variable string for this zone.

   - Coordinates  = Geographical coordinates associated with this zone, in
                    ISO6709 sign-degrees-minutes[-seconds] format.  

   - AdjustedOffset = The timezone's base UTC offset, converted into a positive
                      integer by adding 43200.  This is useful for sorting
                      zones by offset.

All strings are UTF-8 encoded.


CREATING ZONEINFO.xx
====================

Creating the ZONEINFO database requires the contents of `tztools.zip` and also
the latest version of the open source _tzdata_ database.  Refer to the file
`readme.txt` in `tztools.zip` for detailed instructions.