Re: How to calculate the number of seconds since January 1st, 1970 ?

From: "David C. Hoos" <david.c.hoos.sr@ada95.com>
Subject: Re: How to calculate the number of seconds since January 1st, 1970 ?
Date: Tue, 2 Apr 2002 08:03:22 -0600
Date: 2002-04-02T08:03:22-06:00	[thread overview]
Message-ID: <mailman.1017756242.3838.comp.lang.ada@ada.eu.org> (raw)
In-Reply-To: 92694761.0204020124.13aaf9d@posting.google.com

----- Original Message ----- 
From: "P. Renaud" <patrick.renaud@transport.alstom.com>
Newsgroups: comp.lang.ada
To: <comp.lang.ada@ada.eu.org>
Sent: Tuesday, April 02, 2002 3:24 AM
Subject: How to calculate the number of seconds since January 1st, 1970 ?

> Hi all,
> 
> I have to calculate the number of seconds since January 1st, 1970
> 00:00.
> 
> I tried using the Calendar package but it always fails with the
> Time_Error exception (the minus operator used to calculate the
> difference between the current date/time and the reference date/time
> is greater than the duration type limit).
> 
> How can I do to obtain the correct result ?
> 
What's wrong with this?

with Ada.Calendar;
with Ada.Text_IO;
procedure Seconds is
   Elapsed_Time : Duration;
   Unix_Epoch : constant Ada.Calendar.Time :=
     Ada.Calendar.Time_Of
     (Year    => 1970,
      Month   => 1,
      Day     => 1,
      Seconds => 0.0);
   use type Ada.Calendar.Time;
begin
   Elapsed_Time := Ada.Calendar.Clock - Unix_Epoch;
   Ada.Text_IO.Put_Line (Duration'Image (Elapsed_Time));
end Seconds;

What compiler are you using, for which the resulting Duration
value is out of range?

David Hoos

> Thanks for your help.
> 
> P. Renaud
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