RE: seconds since 1601

Thanks Scott - I did some digging also and you are correct on the
nanoseccond. Finally found it referenced on the MS site
http://msdn2.microsoft.com/en-us/library/ms675098.aspx . Other
references I had found were from others trying to use this value. It
looks like it might be something that came out of the Unix world from
some of the references I found.

P.s. thanks for the code snippet! If we even meet up at COMMON or
elsewhere I owe you a beer or two 

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Scott Klement
Sent: Monday, January 15, 2007 3:12 AM
To: RPG programming on the AS400 / iSeries
Subject: Re: seconds since 1601

The date/time stamp is in seconds since 00:00:00 January 1 1601 like 
127122881993040000. Anyone know how to translate the number of seconds

elapsed since 00:00:00, January 1, 1601, to a date and time?

The sample number you've provided does not make sense.  That number is
waaaaaay too high to be a number of seconds. That number equates to
approximately 4028281047 years.  (Take a calculator and divide it by 60
to get minutes, 60 again to get hours, 24 to get days, and 365.25 to get
a number of years.  The result will be 4028281047.)

Since 1601 was only 406 years ago, that number can't possibly be a
number of seconds.  (Unless your users can time travel to 4 billion
years in the
future.)

That being the case, I fired up Google and did some searching to try to
find out what that number really means.  I found the following post,
which was very helpful:
http://tinyurl.com/y5jhll

The post says "First off the 64 bit Integer Time Values (Called
Integer8) represents the number of 100 nanosecond intervals between the
time stamp and January 1, 1601."  That makes a lot more sense -- and
should make it quite easy to calculate in RPG.  Just divide by 10
million to get a number of seconds, then use the date/time operations to
convert it to a timestamp.

Here's some fixed-format RPG code that converts from that timestamp to
an RPG timestamp field:

   D StartPoint      c                   z'1601-01-01-00.00.00.000000'
   D AD_Time         s             20u 0 inz(127122881993040000)
   D Result          s               Z

   C                   div       10000000      AD_Time
   C     StartPoint    adddur    AD_Time:*S    Result

Not so tough when you know what the number means :)   Of course, I'd 
prefer to do it in free format.. so here's the same thing in free
format.

   D StartPoint      c                   z'1601-01-01-00.00.00.000000'
   D AD_Time         s             20u 0 inz(127122881993040000)
   D Result          s               Z

    /free
        Result = StartPoint + %seconds(%div(AD_TIME:10000000));

The next question is "What time zone is that time stamp in?".  That
poist doesn't explcitly say, but they tell you how to convert the
timestamp so that it'll be compatible with the localtime(), gmtime() and
ctime() C functions.  Since I also do programming in C, I know that
those 3 functions take their input in Universal Time Coordinated (UTC)
rather than in the computer's local time.

The ILE environment provides an API called CEEUTCO that will provide
(among other things) the number of seconds difference between your
system's current (local) time, and UTC.  You could add that number to
the timestamp to give you a timestamp that's in the local time zone.

For example, you could do this:

   H DFTACTGRP(*NO)

   D CEEUTCO         PR                  opdesc
   D   Hours                       10I 0
   D   Minutes                     10I 0
   D   Seconds                      8F
   D   Feedback                    12a   options(*omit)

   D StartPoint      c                   z'1601-01-01-00.00.00.000000'
   D AD_Time         s             20u 0 inz(127122881993040000)
   D Result          s               Z
   D junk1           s             10I 0
   D junk2           s             10I 0
   D seconds         s              8F

    /free
        // Get the number of seconds between local time
        // and UTC time.

        CEEUTCO( junk1: junk2: seconds: *omit);

        Result = StartPoint + %seconds(%div(AD_TIME:10000000))
                + %seconds(%int(seconds));

After this code has run, if you display the time stamp value, you'll see

the value as a "sensible" number.   I live in the US Central time zone, 
which is 6 hours earlier than UTC time.  When I run the preceding code,
I get a timestamp of 2003-11-02-17.09.59.000000.

Of course, you (or someone else reading this) may want your date/time in
numeric fields instead of a timestamp field.  If that's the case, you
can do the following to convert it to a number.  (Requires V5R2)

        Date8 = %int(%char(%date(Result):*ISO0));
        Time6 = %int(%char(%time(Result):*HMS0));

Okay, I'll stop trying to anticipate your future questions now :)  But,
if you have some, please ask...
--
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