Re: Recursive Calls

Marc,

  We have written a large inquiry system that allows the user to
select any inquiry from any inquiry in any order all day long. 
Eventually (as soon as the third call) recursion exists.  Our solution
is to have a 'hub' program that does all the calling.  No program
makes any calls, only the hub does.  If program A needs program B it
sets a parameter to 'B' and Returns to the Hub.  The hub then calls
B.  If B then needs A it sets the parameter to 'A' and Returns to the
Hub. The hub then calls A again.  Now in our case we actually save a
stack in the hub of all called programs so that the user can use F12
to return to the previous inquiry until the stack is empty.  In order
for several occuances of 'A' to display the proper data we use a
multi-occurance DS to save the program State when a 'Call' is made and
restore it when a 'Return' is made.

  Another completely different solution that I have seen (but DO NOT
like) is for a reply be added to the system reply list for the error
that comes up when a recursive program is called.  The action to take
is to dup the program 'A' to 'A01' and then call A01 instead of A the
second time.  This DOES work BUT creates a maintenance problem (you
must remove all copies every time A is compiled) and has HUGE overhead
because you are constantly copying programs and also are opening the
same files over and over.

 - Larry

Marc Zylka wrote:
> 
> I'm curious about how most people handle possible recursive calling
> situations.
> We're running V4R1 and coding in RPG/ILE.  We have a situation where program
> A
> is called from a menu.  Program A creates a workorder and then calls Program
> B,
> the workorder maintenance program.  From the workorder maintenance program,
> one can use F6 to create another workorder, thus calling Program A.
> 
> So, the questions:  When Program A calls Program B, can I remove it from the
> program stack?  Can Program B remove it from the stack when it realizes
> that Program A needs to be called?  If program B can remove Program A from
> the stack, what happens when Program B ends and Program A is no longer
> there to go back to?  If any of this can be done, which manual outlines how
> this is done?
> 
> Thanks in advance,
> Marc Zylka ( mzylka@netpath.net )
> 
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-- 
Larry Bolhuis         | What do you want to reload today?
Arbor Solutions, Inc  | 
(616) 451-2500        | Two rules to success in life:
lbolhui@ibm.net       | 1. Never tell people everything you know.
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