Exception vs function-check; ILE vs OPM

["Peter Dow" <pcdow@xxxxxxxxx>]

Hi Everyone,

I posted this to Midrange-L and got no response, possibly because it was
accidentally in HTML format, for which I apologize. Hopefully someone on
this list can give me some insight.

I'm getting a little confused from RTM re exception vs function check and
how error handling occurs when mixing OPM and ILE RPG programs. A particular
vendor's menu program was originally written in RPG, and was recently
converted to ILE RPG. It allows the user to enter commands using either
native syntax or Sys/38 syntax. When executing a menu option, the way they
determine which is which is to assume it is AS/400 syntax and call QCMDEXC
passing the command, with an indicator on the CALL. If it fails, they try
again with QCAEXEC. If that fails, the user is notified.

With ILE RPG, this method fails. The particular menu option in question
happened to be a CHGDTA command. Yes, DFU. Even better (<G>) it was a Sys38
DFU. So the initial call to QCMDEXC shows an *ESCAPE message in the job log
from CHGDTA saying the DFU program specified is not a DFU program
(understandable), but then returns without setting on the error indicator,
so no call to QCAEXEC is ever made.

Compiling the menu program in ACTGRP(*CALLER) or DFTACTGRP(*YES) makes no
difference.

After reading and re-reading the manual, it seems to get down to the
difference between an exception (a *ESCAPE, *NOTIFY or *STATUS message sent
to the call stack entry as the result of a runtime error) and a function
check (an exception message that is not handled by any call stack entry back
to a control boundary or OPM). Both QCMDEXC and QDZCMDP (the CPP for CHGDTA)
are OPM programs.

Based on all that, it appears either QDZCMDP or QCMDEXC somehow "handled"
the exception message so that it does not become a function check. So
finally, my question is, what does "handling" the message consist of? And is
there anyway to change this behavior to mimic the OPM behavior without
modifying the menu program?

TIA

Peter Dow
Dow Software Services, Inc.
909 425-0194 voice
909 425-0196 fax


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