I think using the SVC 99 returned DD name is a "best practice" although if you can make up a guaranteed-unique DD name of your own it's hard to see what's wrong with that. If I had such code and it worked I would not touch it, but for new code I would be using the SVC 99 service.
Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Bob Bridges Sent: Tuesday, March 31, 2020 2:36 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: PARM= vs PARMDD= and symbol substitution In any REXX I write that has to know, I include this statement at the beginning: fbat=(sysvar('SYSENV')='BACK') If SYSVAR('SYSENV') is "BACK", it's running in the background so I set the fbat flag. Elsewhere in the program it checks FBAT: if fbat then 'look for a DD else 'use a predetermined DSN Hm, no one ever told me choosing a random DD name is passé. I have a TEMPDD routine that returns a DD name guaranteed to be unused; otherwise many of my routines would end up conflicting whenever I use them recursively (sort of). ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
