On 10/19/2016 02:40 AM, Guy Harris wrote:
it's not clear what constraints, if any, are placed on the members of tzname[] if TZ is set to :{tzid} or just to {tzid}, e.g. :Europe/Berlin or Europe/Berlin.
POSIX itself places few constraints on tzname if the TZ environment variable is a tzid. However, version 2 and later of the tzfile format mostly defers to POSIX for its newline-enclosed, POSIX-TZ-environment-variable-style strings (used for time stamps far in the future), and this limits us to the POSIX-blessed characters for time zone abbreviations of future time stamps. Although I suppose we could change the tzfile format to extend the character set, that's not something to be done lightly, as I suppose other software relies on things like separating time zone abbreviations with commas, colons, spaces, etc.