Hi Ed, that sounds interesting, too...but is it something I can do from
Rexx without adding the complexity of having to create an ASM routine,
too?
Thank you and best regards,
Billy Ashton
------ Original Message ------
From "Ed Jaffe" <[email protected]>
To [email protected]
Date 8/24/2024 1:20:35 PM
Subject Re: Simple Rexx question
On 8/22/2024 1:01 PM, Bernd Oppolzer wrote:
If checking for a certain DD name is really all that you need
then the easiest and fastest method IMHO is a very small ASSEMBLER (or C or
PL/1) routine
which scans the TIOT (Task I/O table) for this DD name.
The ASSEMBLER version is the easiest and shortest (and fastest); only five to
seven machine instructions.
But you can do it in C or PL/1, too. It is not very complicated, but it does
not look very good in these
languages (especially in PL/1, C is better). If you want, I could send you the
code (offline).
Scanning the TIOT is an *extremely* old-school approach that requires a bunch
of code and DSECTs. And, what if the DD in question was allocated to use the
XTIOT?
IMHO a far easier and better approach is to simply issue 'DEVTYPE
ddloc,XTIOT=YES' where 'ddloc' is the name of the 8-byte field containing the
DD name.
If the DD is not there, you will get RC=4 RSN=4. No abend. No message of any
kind.
-- Phoenix Software International
Edward E. Jaffe
831 Parkview Drive North
El Segundo, CA 90245
https://www.phoenixsoftware.com/
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