Re: Struggling to understand QMHSNDPM API

Hello Bruce,

thank you very much for your help!


Am 29.01.2020 um 21:24 schrieb Bruce Vining <bruce.vining@xxxxxxxxx>:

I see a few little problems. I can't say for sure which is causing the
RNX9998, but fixing these will get past that (but not where you want to go).

First, change the MOVE 'GENERICMSG" MsgFile to MOVEL

Second, initialize the ErrCode (following your example, insert MOVEL
X'00000000' ErrCode prior to the CALLP.

Done. Now I can see my msgline-entry for a brief moment when pressing F10 for the first time after start. Apparently, the following EXFMT overwrites the message line again. If I add a READ from the DSPF after the CALLP, the message stays intact - until I press return, to get back to the main loop executing the EXFMT. I don't have an idea how to cope with that fact. Do you maybe have a hint for me?

Third, while you can now get past the RNX9998 you will find you now get CPF2407 (Message file GENERICMSG in *LIBL*LIBL not found). You need to only set MsgFile once and then leave it alone. Right now, following the second EXFMT, you are concatenating *LIBL to 'GENERICMSG*LIBL' from the first EXFMT processing.

Very clever! Pressing F10 a second time indeed yields a program crash, this time with a dump which reveals that the MsgFile was modified again (added another *LIBL, as you pointed out). By inserting a CLEAR for the struct before filling the variables, I can now press F10 multiple times without crashing. I'm impressed, very precisely deducted!

I updated the source on my web server to reflect latest changes: https://leela.pocnet.net/~poc/msglinpg.txt

Another problem is that ERRSFL documents that the only messages shown are those related to the use of the following DDS keywords:

ERRMSG
ERRMSGID
SFLMSG
SFLMSGID
CHECK(M10)
CHECK(M11)
CHECK(VN)
CHECK(VNE)
COMP
RANGE
VALUES

I don't see any of these keywords being used in MSGLINDF... How are you envisioning that ERRSFL is associated with the messages found in the external message queue?

Good point. Honestly, I don't know how QMHSNDPM works together with a DSPF to actually show a message in the message line. This may be related that I'm not yet very fluent with the messages concept of the OS.
Eventually I want to use QMHSNDPM in an existing, more complex program with SFLs and Detail-Records, additionally to ERRMSGID/SFLMSGID. That DSPF also has ERRSFL set, so I copied that over to have a comparable environment.

There may be other problems, but the above are what jumped out at me. Any reason you're not using a message subfile?

Besides "because I wasn't aware that I need it": As I tested, this clashes with ERRSFL, additionally to the EXFMT mentioned above.

:wq! PoC

PGP-Key: DDD3 4ABF 6413 38DE - https://www.pocnet.net/poc-key.asc