time during standard to DST transition
Jennifer Wang (jennifwa)
jennifwa at cisco.com
Thu Dec 11 18:56:42 UTC 2008
I think in most case when a caller sets the time to 2:10am Mar 8, 2009
in America/Los_Angeles, he does not realize it's the "missing hour". If
he wants 1:10am (which is a valid time), he would use that. So moving
forward to 3:10am seems to make sense.
There are also other code such as normalize_overflow() where we make
adjustments to what caller wants.
From: Scott Atwood [mailto:scott.roy.atwood at gmail.com]
Sent: Wednesday, December 10, 2008 11:26 AM
To: tz at elsie.nci.nih.gov; Jennifer Wang (jennifwa)
Subject: Re: time during standard to DST transition
On Wed, Dec 10, 2008 at 10:43 AM, Jennifer Wang (jennifwa)
<jennifwa at cisco.com> wrote:
We ran into a problem when setting time to the "missing hour"
during transition from standard time to DST time. For example, setting
time to Mar 8, 2009 at 2:10am using America/Los_Angeles time zone
results in error.
Should mktime() skip forward in this case and set the time to
Mar 8, 2009 3:10am?
To me, it seems to make sense to return an error. The time 2:10am Mar
8, 2009 in America/Los_Angeles really is an ambiguous time. You can't
determine the intension of the caller. She could either be counting
forward one hour from 1:10am, or she could be counting back one hour
from 3:10am, which result in different answers. Likewise, calling
mktime() with 2:10am, Nov 2, 2008 in America/Los_Angeles and a negative
value of tm_isdst is similarly ambiguous.
I think both of these cases should return an error.
Cycle tracks will abound in Utopia. ~H.G. Wells
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