Re: Cancelling a program in a program stack

Someone helped us figure it out.

Here is the answer:

   1) Create a message queue(using CRTMSGQ)  for the server application-(you
should only have to do this step once),
   2) In the Init routine of the server app, issue a call to QCMDEXC to
allocate the message queue that was created in #1 above exclusively,
   3) Next, issue another call to QCMDEXC to assign a break handling program
to the message queue created in #1 above,
   4) In the break handling program, use the sndpgmmsg (or the QMHSNDPM
message api) to send an *escape message(with your unique id or at least
unique message text, if using CPF9898 or CPF9897--so you can distinguish it
from others) to your server program,
   5) To stop the program, you need to issue a SNDMSG (or a call to QMHSNDM)
to the
message queue created in #1 to invoke the break handling program and
interrupt the job.

Since the system will interrupt the current jobstream (that has exclusively
allocated the message queue in #1) and transfer control to the break
handling program; and since the break handling program is higher(or deeper)
in the program stack than the system api generating the list of physical
file names; the execution of the sndpgmmsg in #4 will cause the program
stack to collapse back to the call instruction to the system api in the
server program, at which point you would need to trap the exception on the
call to the system api (analyzing the program exception status DS to ensure
that your exception message caused the exception) or allow the exception to
be thrown to a *PSSR routine where a similar process of analyzing the status
DS would need to be instituted.


----- Original Message -----
From: Tim McCarthy <TimM@softwarejungle.com>
To: <MIDRANGE-L@midrange.com>
Sent: Thursday, April 15, 1999 2:28 PM
Subject: RE: Cancelling a program in a program stack


> No. SNDPGMMSG will only send to invocations in the current stack.
> STRSRVJOB doesn't (at least last time I looked) give you that kind of
> control over the serviced job.
>
>
> > -----Original Message-----
> > From: Henrik Krebs [SMTP:hkrebs@hkrebs.dk]
> > Sent: Wednesday, April 14, 1999 5:06 PM
> > To: MIDRANGE-L@midrange.com
> > Subject: Sv: Cancelling a program in a program stack
> >
> > Is this quite true?
> >
> > Can't STRSRVJOB or such do a SNDPGMMSG *ESCAPE to pgmq 3?
> >
> > ----------
> > > Fra: James W Kilgore <email@james-w-kilgore.com>
> > > Til: MIDRANGE-L@midrange.com
> > > Emne: Re: Cancelling a program in a program stack
> > > Dato: 14. april 1999 17:01
> > >
> > > Bob,
> > >
> > > AFAIK, the only way is to design into the applications a mechanism
> > for
> > > external influence, like a data queue.
> > >
> > >
> > >
> > > Bob Luebbe wrote:
> > > >
> > > > Is there a way, for instance from JobA,  to cancel a program in
> > the
> > stack of
> > > > JobB, without actually ending JobB.
> > > >
> > > > For instance, JobB has the following program stack:
> > > >   Program1
> > > >   Program2
> > > >   Program3
> > > >
> > > > Is it possible for JobA to only cancel Program3 in JobB and return
> > control
> > > > to Program2.
> > > >
> > > >
> > > +---
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