Year 300 bug in ILE RPG or ...? (Again)

[bvining@xxxxxxxxxxxx]

Vanya,

I have forwarded your report on to some of the developers.  This does
not appear to be a RPG problem (it is also easily recreated with SQL),
but rather a Date datatype anomaly where the day after Feb 29 300 is
Mar 02 300.

Bruce Vining

>
>        For some strange reason, my previous message was cut and came
> incoplete. Here is the full version.
>
>        Hi folks.
>        I was recently playing with dates and date types in RPG IV (you
>guess why :))), and have found something rather strange.
>
>        Wrote a program to print all leap years from 1 to 9999 using
>simple technique: set (*iso, but doesn't metter) date to March 01, and
>SUBDUR one day from it. If it ends up with Feb 29, it's a leap year. My
>program broke whenever it hit year 300. Same loop, same logic worked for
>all years in range from 1 to 9999, but for 300. Further investigation
>(dump and source debugger) showed that reason for it was that:
>
>(no format)
>D Ddate             s             d     DATFMT(*ISO)
>D Ndate             s           8   0
>
>
>C             Z-ADD   3000301     Ndate
>C    *ISO     MOVE    Ndate       Ddate
>
>set Ddate to '0300-02-29', and each subsequent use of Ddate crashes the
>program, because '0300-02-29' is invalid date (300 is not lep year).
>
>I tried later with string variables and with both numeric and string
>literals, but result was the same:
>
>C   *ISO      MOVE   3000301     Ddate
>or
>C   *ISO0     MOVE   '03000301'  Ddate
>
>Ddate has value of '0300-02-29'.
>
>Even worse, adding 1 day to '0300-02-28' would result with '0300-02-29'
>and than ... crash.
>
>        I've tested it on two V3.7 and one V4.1 system, results are the
>same.  Any ideas? What, so significant, had happened in 300 AD? Or
>something significant (good party :))) took place that night when IBM-ers
>were developing that piece of compiler? Or is it my mistake?
>
>Can't wait to hear from you,
>
>Vanya
>

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