Re: Parameter passing RPV III <--> RPG IV vs. RPG IV <--> RPG IV

Had the following p-list in an RPG III program:

C PL@DAT PLIST C PARM P@DAT1 10
C PARM P@FMT1 4
C PARM P@DAT2 10
C PARM P@FMT2 4
C PARM P@OPER 1
C PARM P@UNIT 1
C PARM P@DURT 3
C PARM P@ERR 1
C PARM P@DUR 5


The above p-list was used in a call to an RPG IV program.
C CALL 'CADATE' PL@DAT
* C P@ERR IFEQ '0'

We converted this program to RPG IV using CVTRPGSRC.  During the first use,
it went into an endless loop.  While debugging, we realized that the P@ERR
parameter in the called program was 3 chars long and not 1.  All zeros meant
no error, while anything else ( '001', '002', '003',...'006') would be an
error.

Now the question: we know that the RPG III program has worked in the past
when invalid data was passed to CADATE, we don't understand why it would
have failed as an RPG IV program; particularly when the fix was to change
P@ERR to 3 chars and the comparison to '000'.  Unless the mismatch in the
parameters had a different effect with an RPG III <--> RPG IV call than they
did with a RPG IV <--> RPG IV call.  It almost seems as if the RPG III P@ERR
ended up with the rightmost char and the RPG IV P@ERR ended up with the
leftmost (as I would expect).

I put together a small RPG III program to test, and it works as you would
expect the 1 char P@ERR ends up with the leftmost char.

So what the heck was going on? Thoughts?

Thanks in advance,
Charles