Doggone computers...durn things always do what you tell them to. On Sun, Dec 24, 2023 at 11:35 AM Tom Brennan <[email protected]> wrote:
> Thanks Peter! Yes, it was the surprise of an 0C4 when I expected 0C1. > Sometimes when totally confusing things like that happen I first assume > the computer itself is at fault, not the code I'm working on. And guess > what, it's always the code :) > > On 12/24/2023 5:58 AM, Peter Relson wrote: > > Tom B wrote > > <snip> > > I was referring to my experience with a JES2 exit which setup its own > > recovery routine. In that code you could see it free any getmain'd > > memory, etc. like you mentioned. But also in that code was an error > > that caused an 0C4. So when the x'00' I added for temporary debugging > > ran that user-coded recovery routine, I was surprised to get an 0C4 > > instead and had to fix the recovery routine. > > > > So of course JES2 had its own recovery routine in place that handled > > the 0C4 and we got a dump and JES2 went on its merry way, perhaps after > > disabling that exit (I can't remember). > > </snip> > > > > I took a weird view of what I suspect you really meant by "0C4 instead". > I'm now thinking > > you just meant that you were surprised that the recovery routine did not > complete successfully. > > But in case you were thinking of what happened to come to my mind, > here's some info: > > > > When the x'00' "instruction" was executed, it would have gotten an > operation exception > > and the most recently established recovery routine (see "special-case" > below) would have gotten control for the 0C1. > > Its SDWA would have shown that. And TCBCMPC would be x'0C1000'. > > > > If that recovery routine then took some exception that resulted in an > 0C4, a newer recovery routine (established by this recovery routine) or, in > the absence of such, the next-oldest recovery routine would have gotten > control for the 0C4. Its SDWA would have shown that . TCBCMPC would now be > x'0C4000'. > > > > Special-Case: if you have established SPIE/ESPIE for a program > interrupt, that exit will get control even if there is a newer-established > ESTAE-type recovery routine. > > > > Peter Relson > > z/OS Core Technology Design > > > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to [email protected] with the message: INFO IBM-MAIN > > > > > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN > -- Jay Maynard ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
