It's even simpler:
I want to know, if the DDNAME is present in the Job Step JCL,
don't care for dynamic allocations etc. Don't even care for the dataset
etc.,
which may be allocated with the DDNAME, because it will be DUMMY anyway
in most cases.
My question is: is the traditional TIOT scan valid in this case? No need
to use
some ASM macros or system services with more features? My guess is: yes,
still valid.
Maybe second question, different use case:
if there is a Job Step allocation with a simple DSNAME, no concatenation:
will the traditional way to get the DSNAME using RDJFCB and SWAREQ
still work? (I hope, I got the macro names right, out of the head).
IIRC, SWAREQ
translates a 3-byte-handle to a valid 31-bit-address ...
Kind regards
Bernd
Am 29.07.2019 um 23:36 schrieb Farley, Peter x23353:
If all you need to know is whether a DD name is allocated or not, I think the DEVTYPE
macro is the simplest method. Any non-zero return code indicates non-existence once you
have the macro invocation working (there is a "syntax" RC that you will never
get after you have it coded to work).
And DEVTYPE is very simple to code as an "__asm" statement in XL C/C++.
Peter
-----Original Message-----
From: IBM Mainframe Discussion List <[email protected]> On Behalf Of
Bernd Oppolzer
Sent: Monday, July 29, 2019 4:50 PM
To: [email protected]
Subject: Re: XTIOT impact?
Most "practical" uses of TIOT searches are for user programs which try to check
if there is a certain DD statement in the job step JCL, used to control a certain program
action.
For me, this is a sort of "third way" of parameter passing to programs, besides
normal JCL parameters and environment.
Sort of nice, because it can be used in every language and the changes to
existing code are minimal (can be applied even very late - 20 years after first
delivery - and in emergency situations).
Example:
//USERRSAF DD DUMMY
checking for existence of USERRSAF in TIOT, and do some program action
depending on this
As far as I unterstand these postings, this use of TIOT scans (in whatever
language) is still valid.
Any comments?
Kind regards
Bernd
Am 29.07.2019 um 22:40 schrieb Seymour J Metz:
Yes, if you use one of those options then the ddname will not be in the TIOT.
If you open a DCB/ACB for a ddname allocated with one of those options, DCBTIO
will be zero.
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