Well, there were a lot of interesting comments and ideas here. My needs
are pretty simple - check to see if the DD statements I need are defined
in my job before I try to read or write them.
I did some testing on using BPXWDYN Info, which gave the clearest
details on the file status, and EXECIO read or write of 1 record. The
results were interesting.
For input:
from instream SYSIN: BPX was an average of 66% faster 99% of the time
(against 10,000 iterations)
from a DD DUMMY: EXECIO was 33% faster 83% of the time
from a PDS member: BPX was 72% faster 99+% of the time
For output:
to an empty PDS member: BPX was 73% faster 99.7% of the time
to a PDS member with data: BPX was 95% faster 100% of the time (I guess
there was a lot of work to set the EOF pointer and such)
to SYSOUT=* (most common): BPX was 78% faster 99+% of the time
to a DD DUMMY file: EXECIO was 63% faster 93% of the time
I don't expect that these files will be DUMMY files in normal usage, so
it seems pretty clear that BPX is the more efficient of the two options
here. However, based on these points:
I only need to check four files in my program
The program will have occasional usage and not many times every day
Someone else may need to support this who is more junior
I already use EXECIO extensively in the program for all my I/O
I am going to use the EXECIO logic. The line count of code is not too
different, and it will be an internal routine, anyway.
Thanks for the options and for offering the other code bits...maybe if I
get more free time down the road, I will do a more exhaustive analysis
of this, but I'm too covered up right now...
Billy
Thank you and best regards,
Billy Ashton
------ Original Message ------
From "Binyamin Dissen" <00000662573e2c3a-dmarc-requ...@listserv.ua.edu>
To IBM-MAIN@listserv.ua.edu
Date 8/22/2024 12:58:28 AM
Subject Re: Simple Rexx question
How about
was1=outtrap("trash.")
was2=trapmsg("on")
"EXECIO 5 DISKR Q1Q2Q3 (FINIS"
x=trapmsg(was2)
x=outtrap(was1)
if rc = 20 /*ddname not found, though trash.1 can be examined */
Let EXECIO do the work
On Wed, 21 Aug 2024 19:28:12 +0000 Billy Ashton
<00000665bda14df5-dmarc-requ...@listserv.ua.edu> wrote:
:>Hi all, I have a simple question, but my searches are eluding me (maybe
:>I don't know what to ask for).
">😁
:>In my Rexx program, before I try to do an EXECIO against it, I want to
:>do something to make sure the DD statement is there and control the
:>error. I tried ListDSI, but that only works on DASD files and not on
:>instream (DD *) data.
">😁
:>How can I test that I have the ABCXYZ DD statement allocated, if it is
:>DD * or DD DATA? Likewise, how can I test for DD JKLMNO that is
:>allocated to SYSOUT=* to be sure it is there (as I am writing via EXECIO
:>to it)?
">😁
:>Thank you and best regards,
:>Billy Ashton
">😁
">😁----------------------------------------------------------------------
:>For IBM-MAIN subscribe / signoff / archive access instructions,
:>send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
--
Binyamin Dissen <bdis...@dissensoftware.com>
http://www.dissensoftware.com
Director, Dissen Software, Bar & Grill - Israel
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