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RE: Timezone Difference Question (Real Studio network user group Mailinglist archive)

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When is CompareRows done?   -   Hadley, Joshua
  RE: Timezone Difference Question   -   Michael Raycraft
   Timezone Difference Question   -   Scott Clausen
    Re: Timezone Difference Question   -   Will Leshner
     Re: Timezone Difference Question   -   Norman Palardy
      Re: Timezone Difference Question   -   Will Leshner
       Re: Timezone Difference Question   -   Norman Palardy
        Re: Timezone Difference Question   -   Will Leshner
         Re: Timezone Difference Question   -   Norman Palardy
    Re: Timezone Difference Question   -   Kevin Ballard
    Re: Timezone Difference Question   -   Christian Schmitz
    Re: Timezone Difference Question   -   Dave Wooldridge
    Re: Timezone Difference Question   -   Norman Palardy
    Re: Timezone Difference Question   -   Frank Bitterlich
     Re: Timezone Difference Question   -   Dean Davis
     Re: Timezone Difference Question   -   Norman Palardy
     Re: Timezone Difference Question   -   Brady Duga
   Re: HandleAppleEvents   -   chris

RE: Timezone Difference Question
Date: 28.08.02 23:27 (Wed, 28 Aug 2002 15:27:33 -0700)
From: Michael Raycraft
UTC is not the same time as GMT. Amatur Radio Operaters ( HAM's) use UTC
instead of GMT. Our project will log the contact and poll the radio for
it's configuration automatically.
MLR

-----Original Message-----
From: Kevin Ballard [mailto:kevin@sb.org]
Sent: Wednesday, August 28, 2002 3:17 PM
To: REALbasic Network Users Group
Subject: Re: Timezone Difference Question

Are you trying to figure out what timezone the user is in? If so, try
the Carbon Declare Library. It can return the number of hours off from
GMT that you are. And it's free.

<http://www.tildesoft.com/Code.html>

On Wednesday, August 28, 2002, at 05:26 PM, Scott Clausen wrote:

> Hello,
> I'm a fairly new RB user who is learning the program in order to
> write amateur radio software for the Mac.
>
> I'm building a contact log and need to know how to have UTC (aka GMT)
> time display. I know how to have a local time automatically entered
> into a field I just can't find anything on entering a time for another
> timezone.

Timezone Difference Question
Date: 28.08.02 22:26 (Wed, 28 Aug 2002 14:26:42 -0700)
From: Scott Clausen
Hello,
I'm a fairly new RB user who is learning the program in order to write
amateur radio software for the Mac.

I'm building a contact log and need to know how to have UTC (aka GMT)
time display. I know how to have a local time automatically entered
into a field I just can't find anything on entering a time for another
timezone.

Also, is there an archive of this list that one can search for answers
to avoid asking questions that were previously answered.

Thanks for the help.

Scott

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Re: Timezone Difference Question
Date: 28.08.02 22:40 (Wed, 28 Aug 2002 14:40:11 -0700)
From: Will Leshner
It actually turns out to be kind of a tricky thing. Does the OS provide
such a facility? The problem is that you can't just have a static table
because of daylight savings. It turns out, for example, that Greenwich
has a summer time much like the US daylight savings time. During summer
time the time in Greenwich is not the same as GMT :)

On Wednesday, August 28, 2002, at 02:26 PM, Scott Clausen wrote:

> I'm building a contact log and need to know how to have UTC (aka GMT)
> time display. I know how to have a local time automatically entered
> into a field I just can't find anything on entering a time for another
> timezone.

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Re: Timezone Difference Question
Date: 29.08.02 03:17 (Wed, 28 Aug 2002 20:17:19 -0600)
From: Norman Palardy
GMT is GMT is GMT

It is not affected by daylight savings.

GMT is always guaranteed to be within 0.9s of UTC by the application of
leap seconds.

On Wednesday, August 28, 2002, at 03:40 PM, Will Leshner wrote:

> It actually turns out to be kind of a tricky thing. Does the OS
> provide such a facility? The problem is that you can't just have a
> static table because of daylight savings. It turns out, for example,
> that Greenwich has a summer time much like the US daylight savings
> time. During summer time the time in Greenwich is not the same as GMT
> :)
>
> On Wednesday, August 28, 2002, at 02:26 PM, Scott Clausen wrote:
>
>> I'm building a contact log and need to know how to have UTC (aka GMT)
>> time display. I know how to have a local time automatically entered
>> into a field I just can't find anything on entering a time for
>> another timezone.
>
> ---
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Re: Timezone Difference Question
Date: 29.08.02 06:11 (Wed, 28 Aug 2002 22:11:00 -0700)
From: Will Leshner
Actually, that was my point. GMT isn't affected by daylight savings.
But any local time is. I figured what Scott wanted to do was be able to
calculate any arbitrary local time for any location in the world. I was
merely pointing out that can be a tricky thing to do.

On Wednesday, August 28, 2002, at 07:17 PM, Norman Palardy wrote:

> GMT is GMT is GMT
>
> It is not affected by daylight savings.
>
> GMT is always guaranteed to be within 0.9s of UTC by the application
> of leap seconds.

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Re: Timezone Difference Question
Date: 29.08.02 07:19 (Thu, 29 Aug 2002 00:19:30 -0600)
From: Norman Palardy
The Mac OS can tell you what the offsets from GMT and allowances for
daylight savings time are
There are places where the Daylight offset is portions of an hour (like
Newfoundland Canada)
But the Mac OS can tell this IF you set the location

On Wednesday, August 28, 2002, at 11:11 PM, Will Leshner wrote:

> Actually, that was my point. GMT isn't affected by daylight savings.
> But any local time is. I figured what Scott wanted to do was be able
> to calculate any arbitrary local time for any location in the world. I
> was merely pointing out that can be a tricky thing to do.
>
> On Wednesday, August 28, 2002, at 07:17 PM, Norman Palardy wrote:
>
>> GMT is GMT is GMT
>>
>> It is not affected by daylight savings.
>>
>> GMT is always guaranteed to be within 0.9s of UTC by the application
>> of leap seconds.
>
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Re: Timezone Difference Question
Date: 29.08.02 16:00 (Thu, 29 Aug 2002 08:00:34 -0700)
From: Will Leshner
Can it tell you for any location in the world or only for your
location? I'm thinking it *knows* all locations but is there a way to
get at that information.

On Wednesday, August 28, 2002, at 11:19 PM, Norman Palardy wrote:

> The Mac OS can tell you what the offsets from GMT and allowances for
> daylight savings time are
> There are places where the Daylight offset is portions of an hour
> (like Newfoundland Canada)
> But the Mac OS can tell this IF you set the location

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Re: Timezone Difference Question
Date: 29.08.02 16:06 (Thu, 29 Aug 2002 09:06:45 -0600)
From: Norman Palardy
set the location and read it

not sure if there's a way to ask for a specific locale

On Thursday, August 29, 2002, at 09:00 AM, Will Leshner wrote:

> Can it tell you for any location in the world or only for your
> location? I'm thinking it *knows* all locations but is there a way to
> get at that information.
>
> On Wednesday, August 28, 2002, at 11:19 PM, Norman Palardy wrote:
>
>> The Mac OS can tell you what the offsets from GMT and allowances for
>> daylight savings time are
>> There are places where the Daylight offset is portions of an hour
>> (like Newfoundland Canada)
>> But the Mac OS can tell this IF you set the location

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Re: Timezone Difference Question
Date: 28.08.02 23:16 (Wed, 28 Aug 2002 18:16:54 -0400)
From: Kevin Ballard
Are you trying to figure out what timezone the user is in? If so, try
the Carbon Declare Library. It can return the number of hours off from
GMT that you are. And it's free.

<http://www.tildesoft.com/Code.html>

On Wednesday, August 28, 2002, at 05:26 PM, Scott Clausen wrote:

> Hello,
> I'm a fairly new RB user who is learning the program in order to
> write amateur radio software for the Mac.
>
> I'm building a contact log and need to know how to have UTC (aka GMT)
> time display. I know how to have a local time automatically entered
> into a field I just can't find anything on entering a time for another
> timezone.

Re: Timezone Difference Question
Date: 28.08.02 23:31 (Thu, 29 Aug 2002 00:31:51 +0200)
From: Christian Schmitz
> Hello,
> I'm building a contact log and need to know how to have UTC (aka GMT) time
> display. I know how to have a local time automatically entered into a
> field I just can't find anything on entering a time for another timezone.

If you use the MBS Plugin, the timezone object may help you.

Mfg
Christian

Re: Timezone Difference Question
Date: 29.08.02 03:04 (Wed, 28 Aug 2002 19:04:07 -0700)
From: Dave Wooldridge
Scott Clausen wrote:

> I'm building a contact log and need to know how to have UTC (aka GMT)
> time display. I know how to have a local time automatically entered
> into a field I just can't find anything on entering a time for another
> timezone.

I recently had to program this kind of functionality into our Lighthouse
application which allows a user to view the current local time in over 65
cities worldwide. The way I did it relies on the user having his personal
computer's local time set correctly. Upon the first-run of the app, the
user must select the closest city (which gets saved in the app's Preferences
for future use). Since the app now knows what time zone the user is located
in (based on his selected city and his computer's clock) and the app also
knows the difference in hours between that selected city and the UTC, I can
then calculate the current UTC time. Once the app knows the current UTC
time, it can apply the same "difference" math equation to find out the
current local time and date in any of the other listed cities.

Unfortunately, since Lighthouse is a commercial application, my company
can't share the source code (sorry), but once I figured out how to calculate
the UTC formula (brief explanation in last paragraph), the coding was
actually quite easy. When coding this yourself, don't forget to include
factors like Daylight Savings which changes the equation in many, many
cities for a limited number of months each year. I have a few methods that
handle this entire process, from calculating UTC to figuring out if a
specific country is currently observing Daylight Savings.

This web site (URL below) was a great reference tool in figuring out the
"difference" in hours for each country from the standard UTC:
http://www.timeanddate.com/worldclock/

Hope that helps....

Regards,
Dave Wooldridge
Electric Butterfly
http://www.ebutterfly.com

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Re: Timezone Difference Question
Date: 29.08.02 03:15 (Wed, 28 Aug 2002 20:15:55 -0600)
From: Norman Palardy
Your right. You do want the difference from UTC which is GMT

GMT is not affected by daylight savings, etc

You can ask the OS for the GMT offset of the machine given it's locale

On Wednesday, August 28, 2002, at 03:26 PM, Scott Clausen wrote:

> Hello,
> I'm a fairly new RB user who is learning the program in order to
> write amateur radio software for the Mac.
>
> I'm building a contact log and need to know how to have UTC (aka GMT)
> time display. I know how to have a local time automatically entered
> into a field I just can't find anything on entering a time for another
> timezone.
>
> Also, is there an archive of this list that one can search for answers
> to avoid asking questions that were previously answered.
>
> Thanks for the help.
>
> Scott
>
> ---
> Subscribe to the digest:
> <mailto:<email address removed>>
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> <mailto:<email address removed>>

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Re: Timezone Difference Question
Date: 29.08.02 11:22 (Thu, 29 Aug 2002 12:22:34 +0200)
From: Frank Bitterlich
Where exactly is the difference between UTC and GMT? In aviation at
least, they are definitely the same thing.

Cheers,
Frank+++

Michael Raycraft wrote:
>
> UTC is not the same time as GMT. Amatur Radio Operaters ( HAM's) use UTC
> instead of GMT. Our project will log the contact and poll the radio for
> it's configuration automatically.
> MLR

Re: Timezone Difference Question
Date: 29.08.02 13:33 (Thu, 29 Aug 2002 05:33:22 -0700 (PDT))
From: Dean Davis
Cocoa provides built in funtionality to convert from
any time zone to any other time zone.

NSDate/NSCalendarDate and NSTimeZone are the classes
for this.

Can any experts figure out how to access those classes
for REALBasic (even though this wouldn't help classic
programmers)

But it is very easy using Carbon Declare Library to
convert between the time zone the Macintosh is set to
and UTC time (which for the purposes of the original
question is equivilent to GMT time)

Dean Davis

--- Frank Bitterlich <<email address removed>> wrote:
> Where exactly is the difference between UTC and GMT?
> In aviation at
> least, they are definitely the same thing.
>
> Cheers,
> Frank+++
>
> Michael Raycraft wrote:
> >
> > UTC is not the same time as GMT. Amatur Radio
> Operaters ( HAM's) use UTC
> > instead of GMT. Our project will log the contact
> and poll the radio for
> > it's configuration automatically.
> > MLR
>
> --
> Günter Schmidt & Co. oHG
> Frank Bitterlich eMail:
> <email address removed>
> Schlosserstr. 2-4 WWW:
> http://www.gsco.de/gsco
> D-60322 Frankfurt Tel.: 069 / 156809-29
> GERMANY Fax: 069 / 156809-28
>
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Re: Timezone Difference Question
Date: 29.08.02 15:54 (Thu, 29 Aug 2002 08:54:58 -0600)
From: Norman Palardy
GMT is UTC +/- .9s at most

On Thursday, August 29, 2002, at 04:22 AM, Frank Bitterlich wrote:

> Where exactly is the difference between UTC and GMT? In aviation at
> least, they are definitely the same thing.
>
> Cheers,
> Frank+++
>
> Michael Raycraft wrote:
>>
>> UTC is not the same time as GMT. Amatur Radio Operaters ( HAM's) use
>> UTC
>> instead of GMT. Our project will log the contact and poll the radio
>> for
>> it's configuration automatically.
>> MLR

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Re: Timezone Difference Question
Date: 29.08.02 16:03 (Thu, 29 Aug 2002 08:03:46 -0700)
From: Brady Duga

On Thursday, August 29, 2002, at 03:22 AM, Frank Bitterlich wrote:

> Where exactly is the difference between UTC and GMT? In aviation at
> least, they are definitely the same thing.

UTC is a replacement for GMT. GMT is based on astronomical observations
made at the observatory in Greenwich England, mainly mean Solar time.
Problem is, mean solar time is variable. UTC on the other hand is based
on the decay rate of cesium-133, or more precisely: "The second is the
duration of 9,192,631,770 periods of the radiation corresponding to the
transition between the two hyperfine levels of the ground state of the
cesium-133 atom." (General Conference of Weights and Measures, 1967) Of
course, the rotation of the Earth has no specific relationship to the
decay rate of cesium-133 (stupid Earth, what was it thinking?). In
fact, the rotation of the earth isn't exactly predictable, and varies
over the ages. To avoid UTC having no relationship to the time of day,
a hacky fudge factor ... err ... I mean a very well designed
scientifically proven method of leap seconds was introduced. Basically,
at midnight they add or lob off a few seconds, thus making UTC just as
unpredictable as GMT. There is some irony in the whole system, as the
notion of time was basically a way to record the passage of days and
seasons, but has now evolved to a new realm where it has no
relationship to days or seasons.

So, to sum up, UTC and GMT are completely different, but for more uses
are completely identical.

--Brady
The La Jolla Underground

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