Subject: Re: RDATEs in VTIMEZONEs

From: [email-masked]
Date: Wed, 2 May 2001 12:35:40 -0400

Damon wrote on 05/01/2001 03:56:02 PM:
> In RFC2445, pg 64 it says:
> 
>    Alternatively, the "RDATE" property can be used to define the onset
>    of the observance by giving the individual onset date and times.
>    "RDATE" in this usage MUST be specified as a local DATE-TIME value in
>    UTC time.
> 
> Yet the example just below has:
> 
>      DTSTART:19971026T020000
>      RDATE:19971026T020000
> 
> Here the RDATE is not a UTC time - it doesn't have a 'Z'.
> It looks like a local 'wall clock' time, like DTSTART.
> 
> 
> So which is it - local time or UTC? I'd prefer local time, as that
> keeps it the same as the DTSTART and RRULE times.

You are correct to note that this is indeed contradictory text and the 
answer is that the last part of the text is wrong.  It should say "local 
time" and not "UTC time".

Wait a minute... Hmm, now that I mull it over I can see why UTC actually 
may be a better answer though.  I dont want, say, Los Angeles to 
incorrectly use 2AM PST/PDT as the shift time for New York who actually 
shifted at 2AM EST/EDT!  The shift for New York occurs at 11PM PST/PDT the 
day before!!!  So by using UTC it makes compensating for shifts in other 
TZs correct...

I think the examples are wrong in that case...  Damn, I need to get some 
caffine!

Bruce
PS: Are you sure thats p64?  Its on p65 in my copy and the one in the 
offical RFC editors site...
===========================================================================
Bruce Kahn                                INet: [email-masked]
Iris Associates                          Phone: 978.392.5335
Westford, MA, USA 01886                    FAX: and nothing but the FAX...
Standard disclaimers apply, even where prohibited by law...

---

From: Damon Chaplin <[email-masked]>
Date: Wed, 02 May 2001 15:01:29 -0400

[email-masked] wrote:

> Wait a minute... Hmm, now that I mull it over I can see why UTC
> actually may be a better answer though.  I dont want, say, Los Angeles
> to incorrectly use 2AM PST/PDT as the shift time for New York who
> actually shifted at 2AM EST/EDT!  The shift for New York occurs at
> 11PM PST/PDT the day before!!!  So by using UTC it makes compensating
> for shifts in other TZs correct...

I'm not sure I understand the problem.

I don't think the VTIMEZONE should be interpreted in any other timezone.
A local RDATE would mean using the UTC offset that is in effect before
the time change (i.e. from the other components in the VTIMEZONE).

DTSTART values must be local times in VTIMEZONES as well.

Damon

> offical RFC editors site...

My fault. I was assuming the page numbers were at the top of the pages.
Maybe a separator '---------' between pages would be handy.