RE: What's the difference?

["Bartell, Aaron L. (TC)" <ALBartell@xxxxxxxxxxxxxx>]

>If we're talking about a program uses that %parms, it most certainly can
restrict reference to the non passed parameters just as a subprocedure that
uses %parms can.

You are absolutely correct, I had forgotten that you can do it on an *entry
parameter list.  Guess I didn't turn my bulb on this morning;-)

Aaron Bartell

-----Original Message-----
From: Buck Calabro [mailto:Buck.Calabro@commsoft.net]
Sent: Monday, November 18, 2002 11:51 AM
To: rpg400-l@midrange.com
Subject: RE: What's the difference?


>I was coming from the stand point of
>if program A called program B with 0
>(zero)parameters, but program B was
>expecting 1 parameter then program B
>would come up with a "pointer not
>set for location reference" error when
>that field was referenced;

If we're talking about a program that does NOT use %parms, and a
subprocedure that does NOT use %parms, the behaviour you describe is
identical in procs and progs.  That is, if the called code does NOT
explicitly check to see how many parameters have been passed, then that code
will have Bad Things happen when it references the non-passed parameter.

I say Bad Things, because you may have a stale pointer left on the stack,
and NOT get a MCH3601, but some other unpredictable failure as the called
code works on some other part of memory it doesn't own.

If we're talking about a program uses that %parms, it most certainly can
restrict reference to the non passed parameters just as a subprocedure that
uses %parms can.  An earlier reply had a code snippet from a working program
that demonstrates this.

That's why I feel that subprocedures do not offer more functionality over
programs in this particular.

There was a reply about *OMITting a parameter in the middle of a list, but I
honestly have never seen a need to do that in a subprocedure and so freely
admit to ignorance of how to implement it in a called program.  I also
freely admit to not being the brightest bulb in the pack.  Perhaps there's
more demand for this than I ever thought of in my limited experience.
Something to keep in mind when comparing procs to progs though.
  --buck
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