Expected output of zdump(8)

[Olson, Arthur David (NIH/NCI) [E]]

This is the expected behavior on systems where time_t's are 64 bits and
ints are 32 bits; the year associated with the most negative (or most
positive) 64-bit value won't fit into 32 bits, eventually leading to the
NULL result.

				--ado

-----Original Message-----
From: Edwin Groothuis [mailto:edwin at mavetju.org] 
Sent: Friday, March 28, 2008 7:53 AM
To: tz at lecserver.nci.nih.gov
Subject: Expected output of zdump(8)

Greetings,

I was wondering why zdump(8) was so slow on one of my machines.
It's a known issue, old zdump.c code. So I grabbed a copy of the
new zdump.c from tzcode2008a. But it raised a couple of questions
for me.

On a 32 bit machine running FreeBSD 6.3 I get this:
(/etc/localtime is /usr/share/zoneinfo/Australia/Sydney)

[~/tzcode] edwin at k7>./zdump -v /etc/localtime 
/etc/localtime  Fri Dec 13 20:45:52 1901 UTC = Sat Dec 14 06:45:52 1901
EST isdst=0
/etc/localtime  Sat Dec 14 20:45:52 1901 UTC = Sun Dec 15 06:45:52 1901
EST isdst=0
/etc/localtime  Sun Dec 31 14:00:59 1916 UTC = Mon Jan  1 00:00:59 1917
EST isdst=0
/etc/localtime  Sun Dec 31 14:01:00 1916 UTC = Mon Jan  1 01:01:00 1917
EST isdst=1
[...]
/etc/localtime  Sat Oct  3 15:59:59 2037 UTC = Sun Oct  4 01:59:59 2037
EST isdst=0
/etc/localtime  Sat Oct  3 16:00:00 2037 UTC = Sun Oct  4 03:00:00 2037
EST isdst=1
/etc/localtime  Mon Jan 18 03:14:07 2038 UTC = Mon Jan 18 14:14:07 2038
EST isdst=1
/etc/localtime  Tue Jan 19 03:14:07 2038 UTC = Tue Jan 19 14:14:07 2038
EST isdst=1

On a 64 bit machine running FreeBSD 6.3 I get this:

[~/tzcode] edwin at mavetju.org>./zdump -v /etc/localtime 
/etc/localtime  -9223372036854775808 = NULL
/etc/localtime  -9223372036854689408 = NULL
/etc/localtime  Sun Dec 31 14:00:59 1916 UTC = Mon Jan  1 00:00:59 1917
EST isdst=0 gmtoff=36000
/etc/localtime  Sun Dec 31 14:01:00 1916 UTC = Mon Jan  1 01:01:00 1917
EST isdst=1 gmtoff=39600
[...]
/etc/localtime  Sat Oct  3 15:59:59 2037 UTC = Sun Oct  4 01:59:59 2037
EST isdst=0 gmtoff=36000
/etc/localtime  Sat Oct  3 16:00:00 2037 UTC = Sun Oct  4 03:00:00 2037
EST isdst=1 gmtoff=39600
/etc/localtime  9223372036854689407 = NULL
/etc/localtime  9223372036854775807 = NULL

That big positive and negative number is the effect of gmtime().

I got the same results on the 64 bit version of Linux FC6.

Now my question is... Is this behaviour "as expected" and the same
on other 64 bit operating systems like Solaris, MacOS/X and others
(if you have one name it :-) ?


Edwin

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