Re: Newbie Q: How to program in UTC (time/calendar) ?

[reinkor <reinkor@gmail.com>]

Thanks to all. Now I think I got it !

And giving the argument "Time1" to UTC_Time_Offset" like this:

 UTC_Time_Offset(Time1)

insted of only UTC_Time_Offset (which is the same
as "UTC_Time_Offset(Clock))", then I get consistency:

Time1: 1970-01-01 00:00:00
Time2: 1969-12-31 23:00:00
UTC_Time_Offset:       60

Lesson learned: "remember the argument for UTC_Time_Offset" !   :-)

reinert

PS, new program code:
-----------------------------------------------------------------------------
with Text_IO;
use  Text_IO;

with Ada.Calendar.Formatting,Ada.Calendar.Time_Zones;
-- with Ada.Calendar.Aritmetric;
use  Ada.Calendar,Ada.Calendar.Formatting,Ada.Calendar.Time_Zones;

procedure t1 is

   package Int_Io  is new Text_IO.Integer_Io (Integer);
   use Int_Io;

   Time1,Time2 : Time;

begin

   Time1 := Value("1970-01-01 00:00:00");
   Time2 := Ada.Calendar.Time_Of(1970,1,1,0.0);

   Put("Time1: ");Put(Image(Time1));New_Line;
   Put("Time2: ");Put(Image(Time2));New_Line;

   Put("UTC_Time_Offset: ");Put(Integer(UTC_Time_Offset(Time1)),8);

end t1;





On 30 Mar, 18:52, "Jeffrey R. Carter"
<spam.jrcarter....@nospam.acm.org> wrote:
> reinkor wrote:
> >    Time1 := Value("1970-01-01 00:00:00");
> >    Time2 := Ada.Calendar.Time_Of(1970,1,1,0.0);
>
> >    Put("Time1: ");Put(Image(Time1));New_Line;
> >    Put("Time2: ");Put(Image(Time2));New_Line;
>
> >    Put("UTC_Time_Offset: ");Put(Integer(UTC_Time_Offset),8);
>
> > This gives the following output on my computer:
>
> > Time1: 1970-01-01 00:00:00
> > Time2: 1969-12-31 23:00:00
> > UTC_Time_Offset:      120
>
> > The first line I now understand reflects that both "Value"
> > and "Image" has parameter Time_Zone = 0 (UTC). I.e. "Time1"
> > can be understood to have value 1970-01-01 00:00:00 (UTC).
> > "But "Time2" is 1970-01-01 00:00:00 *minus* one hour (only), and
> > UTC_Time_Offset = 120 (2 hours).
>
> I suspect you've recently gone on
> daylight-savings/summer/whatever-it's-called-where-you-are time, which is UTC
> +02:00 (120 mins), but on 1970 Jan 01 you were on regular time, which is UTC +01:00.
>
> --
> Jeff Carter
> "I don't know why I ever come in here. The
> flies get the best of everything."
> Never Give a Sucker an Even Break
> 102