In CF8
<cfset myDate = createDate(2010,3,14) />
<cfdump var="#myDate#" /><br />
UTC<cfdump var="#GetHttpTimeString(myDate)#" /><br /><br />
<cfset myDate2 = DateAdd('s',1271779666,myDate) />
<cfdump var="#myDate2#" /><br />
UTC<cfdump var="#GetHttpTimeString(myDate2)#" /><br /><br />
<cfset myDate = createDate(2010,3,15) />
<cfdump var="#myDate#" /><br />
UTC<cfdump var="#GetHttpTimeString(myDate)#" /><br /><br />
<cfset myDate2 = DateAdd('s',1271779666,myDate) />
<cfdump var="#myDate2#" /><br />
UTC<cfdump var="#GetHttpTimeString(myDate2)#" /><br /><br />
Output was:
{ts '2010-03-14 00:00:00'}
UTC Sun, 14 Mar 2010 05:00:00 GMT
{ts '2050-07-01 17:07:46'}
UTC Fri, 01 Jul 2050 21:07:46 GMT
{ts '2010-03-15 00:00:00'}
UTC Mon, 15 Mar 2010 04:00:00 GMT
{ts '2050-07-02 16:07:46'}
UTC Sat, 02 Jul 2050 20:07:46 GMT
---- Tom McNeer <[email protected]> wrote:
>
> Okay,
>
> So - it wasn't a JVM issue. Updating it did not change the results.
>
> And Steve was right, in a way. But I still don't understand why it should be
> this way.
>
> First, Steve, I understand what you're saying about "whenever you display a
> time." But in practice, I'm not displaying a time at all. I'm simply
> creating a date/time value and adding a number of seconds to it, then
> inserting into a database.
>
> So to my way of thinking - and according to every doc I've ever read - the
> dateAdd function should do exactly what you tell it to do: just add the
> increments to the original date.
>
> But what's happening DOES involve DST - though not the time zone. I don't
> know why. It shouldn't. But it does, at least in CF9.
>
> Try this for yourself: Daylight Savings Time began at 2:00 AM Eastern on
> March 14, 2010. So run the following:
>
> <cfset myDate = createDate(2010,3,14) />
> <cfdump var="#myDate#" /><br><br>
> <cfset myDate2 = DateAdd('s',1271779666,myDate)>
> <cfdump var="#myDate2#" /><br><br>
>
> myDate is two hours _before_ DST went into effect. On two different CF9
> servers, one on EDT, the other on CDT, the result for myDate2 was:
> {ts '2050-07-01 17:07:46'}
>
> Now change the createDate to (2010,3,15) - _after_ DST went into effect. On
> the same servers, the result was:
> {ts '2050-07-02 16:07:46'}
>
> The original date was changed by a day. But the result of the dateAdd
> statement changed by 23 hours.
>
> I wish I could test this on CF8 and/or 7, but the only servers with those
> versions to which I have access are in Arizona, where they don't use DST.
> Those servers return the 16:07:46 timestamp. But without having the machines
> set to DST, I can't tell if CF is acting differently or not.
--
http://www.linkedin.com/pub/roger-austin/8/a4/60
http://twitter.com/RogerTheGeek
http://www.misshunt.com/ Home of the Clean/Dirty Magnet
http://www.ncdevcon.com/ TACFUG 2010 Conference in North Carolina
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