> For example, without having done an exhaustive analysis, I'd guess > that all the PI fields in the CVT other than CVTUSER are intended to > be read-only.
It's also not safe to assume that you're the only one modifying, e.g., CVTUSER, TCBUSER. BTDT,GTS (no tee shirt, just the scars.) -- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> on behalf of Peter Relson <rel...@us.ibm.com> Sent: Thursday, June 13, 2019 8:26 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: What happens if an SMF exit modifies the SMF record? <snip> > due to security and integrity of the SMF records themselves, IBM is not talking much about it. Security by obscurity? </snip> No. These are updates by authorized programs. Neither security nor integrity is a factor. One ought to be asking for what reason an exit routine would update an SMF record. Can it? Sure. Should it? Usually not. Most programming interfaces (far from all, of course) are intended to be for read-only but only rarely is that explicitly stated. For example, without having done an exhaustive analysis, I'd guess that all the PI fields in the CVT other than CVTUSER are intended to be read-only. Probably one ought to go with "if it's not obvious that a field is intended to be written into, then don't write into it (or ask for the documentation to make it clear one way or another)" Long ago I had hoped to gain traction for indicating that a PI field was read-only vs read/write (such as placing that information within the external classification section of the macro prolog which in turn is used within the data areas books). Obviously that hope did not come to fruition. Peter Relson z/OS Core Technology Design ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
