Another alternative to developing your own trace facility is to use the
builtin GTRACE macro for tracing under GTF.
You can use different trace ids to diagnose different conditions.
GTF would be started with the USRP option specifying the IDs relevant to
the current problem being analyzed.
When GTF is not active, the overhead should be negligible.
The trace entries can be analyzed later under IPCS.
Allan
On Thu, Feb 26, 2026 at 9:57 AM Rob Scott <
[email protected]> wrote:
> Even if he was in this specific instance, I still think a generic trace
> facility for ANY environment and psw key would be a extremely good
> investment.
>
> The time spent crafting it might seem off-putting at first, however the
> payback in time savings for him (and the members of this forum/list) would
> be worth it in the long run.
>
> In today's environment, avoiding Key0 for ISV and user-written authorized
> code is a wise decision (IMHO).
>
> As an aside, I think we (SDSF development) solve 95% of our problems using
> our internal trace tool - we only break out the big guns (XDC) for the
> really hard stuff.
>
> Rob Scott
> Rocket Software
> ________________________________
> From: IBM Mainframe Discussion List <[email protected]> on behalf
> of Dave Day <[email protected]>
> Sent: 26 February 2026 2:35 PM
> To: [email protected] <[email protected]>
> Subject: Re: Debugging multitasking applications
>
> EXTERNAL EMAIL
>
>
>
>
> I thought I read in one of the earlier posts that the app was running
> authorized.
>
>
> On 2/26/2026 8:29 AM, Rob Scott wrote:
> > Dave
> >
> > PTRACE requires Key0 so would not be suitable for Key8 client code or
> Key1-7 server code.
> >
> > Rob Scott
> > Rocket Software
> > ________________________________
> > From: IBM Mainframe Discussion List <[email protected]> on
> behalf of Dave Day <[email protected]>
> > Sent: 26 February 2026 1:38 PM
> > To: [email protected] <[email protected]>
> > Subject: Re: Debugging multitasking applications
> >
> > EXTERNAL EMAIL
> >
> >
> >
> >
> > PTRACE ?? Already has the internal buffers and can format in STCK order
> > using IPCS.
> >
> > -- Dave
> >
> > On 2/26/2026 3:06 AM, Rob Scott wrote:
> >> Joseph,
> >>
> >> I am sure that I have advised this more than once in the past, but I
> will repeat myself in case you missed it.
> >>
> >> You are working in a development environment without access to a
> premium debugging product like z/XDC and you seem to spend quite a lot of
> time guessing about what your programs are doing. I strongly suggest you
> "stick a pin" on where you are now with your current project and spend a
> month or so writing yourself a generic internal trace facility. Something
> that can record :
> >>
> >> (o) Registers and current PSW
> >> (o) CSECT name and offset within it
> >> (o) A sequence of trace payloads so that you can print/dump out areas
> of memory
> >>
> >> Write the trace data to an internal memory buffer and then author
> something that can expose the contents in STCK order.
> >>
> >> This could be one or more of :
> >>
> >> (o) IPCS REXX exec
> >> (o) Some form of trace print dataset (or SYSOUT) allocated to a special
> DD name
> >>
> >> Rob Scott
> >> Rocket Software
> >>
> >>
> >> ________________________________
> >> From: IBM Mainframe Discussion List <[email protected]> on
> behalf of Tony Harminc <[email protected]>
> >> Sent: Wednesday, February 25, 2026 11:59 PM
> >> To: [email protected] <[email protected]>
> >> Subject: Re: Debugging multitasking applications
> >>
> >> EXTERNAL EMAIL
> >>
> >>
> >>
> >>
> >>
> >> On Wed, 25 Feb 2026 at 13:13, Joseph Reichman <
> >> [email protected]> wrote:
> >>
> >>> I am in hard loop waitting for the task to do a wait on a TCB so I
> keep on
> >>> looping looking for the X’80’
> >>>
> >> I wouldn't call it a hard loop if there is an STIMER wait-a-bit in it.
> >>
> >>
> >>> What I am trying to do is make sure the subtask gets to certain point
> of
> >>> sitting for work
> >>>
> >> Why do you want to loop for this? Do you have something else to do while
> >> you loop? If not, just wait for your subtask to post its "I'm ready" ECB
> >> (you passed in the address in the parameter list, right?), rather than
> >> waiting for the subtask to wait. If you are concerned about the subtask
> >> failing before it posts its "I'm ready" ECB, then WAIT on the first of
> the
> >> "I'm ready" ECB and the ECB you specified with ECB= on the ATTACH[X].
> >>
> >> So the code in the main task is somewhat
> >>> Checktask
> >>> TM 0(R10),x’80’
> >>> BO. Next task
> >>> Stimer wait a bit
> >>> B checktask
> >>> Bexttask
> >>>
> >>> While waitting I due issue the stimer a few times
> >>> All of sudden I get a abend with r14 pointing to SVC 3
> >>>
> >> What abend? Are we to guess?
> >>
> >> How can that be
> >> A program that receives control via LINK or ATTACH will have R14
> pointing
> >> to the SVC 3 in the CVT. (Under TSO TEST R14 will generally point to an
> SVC
> >> 97.)
> >>
> >> I think it has something to do with debugging multitasking programs
> >> Well if you are issuing ATTACH (you've only told us about one of them so
> >> far), then it's certainly possible. Are you starting your program under
> >> TEST, or did you bring TEST into the picture only after encountering
> your
> >> whatever-it-is Abend?
> >>
> >> As always, more info is needed.
> >>
> >> Tony H.
> >>
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