Re: Different epochs, same time.

[Eugene van der Pijll]

Mark Fox schreef:
 time_zone = 'America/Edmonton');

That's the problem.

 2004-10-31T01:03:09 = 1099209789
 2004-10-31T01:03:09 = 1099206189

It's during the switch from DST to normal time. Because of DST, times in 
local timezones are not guaranteed to be unique.

 ... for my
 purposes I need the same date to map to the same epoch.

Then you should probably use dates in UTC (or another timezone without
DST, for example one expressed by an offset, for example '+0700' or
something like that). Or you can accept that your records will be
confused during 1 hour per year.

Eugene

Re: Different epochs, same time.

[Mark Fox]

Greetings,

My thanks to Eugene and Andrew for their quick replies.

In response to Andrew, it's not that I haven't been reading the docs,
it's that I wasn't able to *understand* them.  And that's my problem,
not the docs. ;)

I hadn't realized how fundamentally ambiguous the fall back
time-change was in local time.  Unfortunately, I'm actually stuck with
local time, so I'm going to have to hack out a solution.

Thanks for the prompting.


Mark


On Apr 8, 2005 11:01 AM, Mark Fox [EMAIL PROTECTED] wrote:
 Greetings,
 
 I've got a problem.  It's probably a misunderstanding on my part.
 
 Here's a script:
 
 ---
 #!/usr/bin/perl -w
 
 use strict;
 use warnings;
 
 use DateTime;
 
 my $dt1 =
 DateTime-new(year = 2004,
   month = 10,
   day = 31,
   hour = 1,
   minute = 3,
   second = 9,
   time_zone = 'America/Edmonton');
 
 print $dt1-datetime(), ' = ', $dt1-epoch(), \n;
 
 my $dt2 =
 DateTime-from_epoch(epoch = 1099206189, time_zone = 
 'America/Edmonton');
 
 print $dt2-datetime(), ' = ', $dt2-epoch(), \n;
 ---
 
 And here's the output:
 
 ---
 2004-10-31T01:03:09 = 1099209789
 2004-10-31T01:03:09 = 1099206189
 ---
 
 This is a problem because I have dates that are sometimes specified as
 human-readable strings and sometimes as seconds-from-the-epoch.  I
 convert the former to the latter and then go to work, but for my
 purposes I need the same date to map to the same epoch.  The whole
 point of what I'm doing is to match the dates in human-readable string
 to the dates as seconds-from-the-epoch.
 
 What am I doing wrong?
 
 
 Mark