zdump /zoneinfo question

[Reynolds, John]

Hello,

Please excuse the intrusion. I found this email address in some documents I
downloaded from elsie.nci.nih.gov. I'm looking for some information or
perhaps an online reference that can help me relate the output from the
zdump utility to the changes for daylight savings for a particulat timezone.
I've read the zic, zdump, ctime and localtime man pages. The zic manpage
explains the format of the tz data files I found your name in. The output of
zdump tells me when there is a change in the rules for a timezone but it
doesn't seem to tell me what the rules are. In other words, given a
particular zoneinfo file, how can I determine the zone and rules that were
used to create it?
My reason for asking is, how can I tell if the curent zoneinfo file is
accurate given that governments can change the rules at any time.
I've tried some experiments creating my own zoneinfo files then using zdump
to display information about it but I see no way of determining the rules.
Thanks for any help!
John Reynolds
john.reynolds at sciatl.com