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From: Adam Beneschan <adam@irvine.com>
Newsgroups: comp.lang.ada
Subject: Re: Ada.Calendar and NTP (and Unix Epoch)
Date: Tue, 24 Jul 2012 09:37:07 -0700 (PDT)
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Date: 2012-07-24T09:37:07-07:00
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On Tuesday, July 24, 2012 5:27:30 AM UTC-7, erlo....@gmail.com wrote:
> > Where is a problem then?
> > 
> >    E1 + T1 vs. E2 + T2
> > 
> > <=>
> > 
> >    T1 vs. (E2 - E1) + T2
> > 
> > Where E2 - E1 is the time offset between the epochs.
> 
> That's true, the issue here is that I was fooled by Ada.Calendar.Conversion spec
> into thinking that I can use To_Ada_Time to convert the NTP epoch base (1-1-1900 0:00) to a variable of type Time. This would make it easy to calculate
> the offset between the two epochs:
> epoch_diff := To_Ada_Time(70, 0, 1, 0, 0 ,0 0) - To_Ada_Time(00, 0, 1, 0, 0 ,0 0)

If all you're trying to do is figure out the number of seconds between 1/1/1970 and 1/1/1900 by using an Ada Time type, you can do this easily by figuring out the number of seconds between 1/1/1970 and 1/1/1901, and adding a constant.

                           -- Adam