Re: Recursion in RPG

[Rory Hewitt <rory.hewitt@xxxxxxxxx>]

Phil,

I'm not sure what the author is saying here - whether or not there is a
RETURN statement, if the procedure is several levels deep (i.e. it has
recursed multiple times), it will still have to travel back though each
prior level on its way to the top. Short of using the setjmp() and
longjmp() operations to jump straight out, there's nothing that can be done
about this. That being said, it's not what I would call a problem, as such.

As far as reaching a system limit, this would have nothing to do with
long-running jobs specifically - it would simply be the maximum number of
recursions - I don't know what that is, but I'd guess its probably 65535.

Rory


On Thu, Feb 14, 2013 at 10:50 AM, ssc1478 <ssc1478@xxxxxxx> wrote:

> I recently read this article:
> http://ibmsystemsmag.com/ibmi/developer/rpg/rpgle_recursion/
>
> and was interested in this comment:
> "Even though this procedure doesn’t return a value, it’s a good idea to
> have a return statement on the end so the program can exit right away after
> it reaches the end of MGACCM. Otherwise, it will unwind itself by going
> from the Endif line to the end of the procedure for as many records as were
> written."
>
> What I've noticed is that each recursive call puts an entry on the call
> stack, and at the end it "unwinds" down the call stack until it can exit
> the subprocedure.  I thought the author's comment above was addressing
> that, but it made no impact on my test pgm.
>
> Is that the expected behavior?  I'm worried about a long-running job
> running into a system limit.  Does anyone know?
>
> Thanks,
> Phil
> --
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