Re: Recursion in RPG

On 14 Feb 2013 11:26, Rory Hewitt wrote:

<<SNIP>> As far as reaching a system limit <<SNIP>> it would simply
be the maximum number of recursions - I don't know what that is, but
I'd guess its probably 65535.

I do not recall a specific number, but IME a limit was generally reached by exceeding the storage limit for the available PASA in the combined stack frames; i.e. a numeric limit could not be reached. Such a process experiences a painful death because the cancel handlers generally require their own automatic storage, but those too would be unable to operate [because no space was reserved for them]. That experience has taught me that whatever is to be done recursively would best be designed and coded to minimize consumption of PASA.

Given the following C++ doc, I presume the numeric limit is much smaller as well:
http://publib.boulder.ibm.com/infocenter/iadthelp/v7r1/topic/com.ibm.etools.iseries.pgmgd.doc/cpprog156.htm
"... The maximum auto storage is 16 MB and there is a recursion limit of approximately 21743 levels deep"

I seem to recall reading somewhere that RPG has a numeric recursion depth limit. A doc search was fruitless. And there may or may not be a processing option [an H-spec] like within CL to adjust such a limit: DCLPRCOPT SUBRSTACK(25).

Since I waited so long to send this reply, Ken has since responded in this thread with the number of 255 for RPG, and in searching the web and docs I had found a message in the archive also from Ken saying the same thing, but no mention in either about an option to override that limit:
# Subject: RE: Can an RPG module call another RPG module?
# From: Ken Sims <mr2087@xxxxxxxxx>
# Date: Fri, 06 Dec 2002 13:42:39 -0800
http://archive.midrange.com/rpg400-l/200212/msg00134.html