On Mon, Apr 23, 2012 at 5:05 PM, Andrew Henshaw <hens...@me.com> wrote:
> > Its odd as I had expected livecode to convert the seconds to and from a > date in the same way as all the online tools that convert unix time based > on seconds since the epoch, but apparently it does depend on which format > you convert to as to what time it is. > > I think you may have just needed to do a little more checking. I went to this website: http://www.epochconverter.com/ and input your number: 1335049200 and it came up with, as you say: 21 Apr 2012 23:00:00 GMT, BUT it also came up with 22 Apr 2012 07 19:00:00 which is the time corrected for the time zone I'm currently in. I then test in Terminal on OS X with: $ date -r 1335049200 and the it came back: Sun 22 Apr 2012 19:00:00 EDT - a local time, NOT a GMT time. I then tested using the -u option: $ date -ur 1335049200 and it came back: Sat 21 Apr 2012 23:00:00 UTC - as per your online converters. All you are seeing when you use an online converter is that they've probably set the -u option so the output is UTC (GMT) rather than the default time zone, which would have been where ever the server is located. What you don't appreciate is that this is because they haven't gone to the trouble, as www.epochconverter.com obviously did, to write the extra code to search your computer to find what time zone you're in to output the conversion into something more usable to you. The helpful people at RunRev have done that for you with LiveCode. Terminal and LiveCode (which I'm guessing is simply using OS X underlying Unix for the answer) base all their 'seconds' on the same Epoch as the online Unix converters you have used. The only difference is, Terminal and LiveCode KNOW what time zone your computer is in so give you the answer relative to your time zone. This is actually what you want for ALL date and time manipulation presented to a user. Where dates and time become tricky is when you are trying to compare them between different users located around the world. My general rule of thumb is: If you are only interested in avoiding confusion surround date formats (is 2/4/12 2nd Apr or Feb 4th) then use dateItems. If time is involved, the start with internet date (as it includes the UTC (GMT) offset) and then convert to dateItems and apply appropriate UTC conversions. If you haven't gathered, I love LiveCode and dateItems. It makes it so easy to figure out what date and time it was 83 days 98 hours 76 min ago in India, which has an offset of UTC + 5hrs 30 min. Actually it's not that hard with seconds, but dateItems just gel with my simple mind. HTH _______________________________________________ use-livecode mailing list use-livecode@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode
