No integrity violation at all. Simply bad coding.
While one could suggest a bi-address mode OPEN, I doubt that anyone other than you would be interested. Finally, IBM-MAIN would be much more appropriate. On Fri, 11 Jun 2021 21:36:20 +0100 MELVYN MALTZ <0000072265160664-dmarc-requ...@listserv.uga.edu> wrote: :>1) An OPEN/CLOSE with MF=L,MODE=24 can be overlayed with an :> MF=E,MODE=31 (and vice-versa). This results in destruction of the list, :> abends would occur :> :>2) An OPEN/CLOSE with MF=L with (say) 2 entries can be overlayed with an :> MF=E with 3 entries. The end-of-list bit isn't touched, but a storage violation :> occurs :> :>It is true that the "DFSMS Macro Instructions for Data Sets" does warn against mixed mode and MF=L/E length differences with the usual 'unpredictable results may occur' :> :>The first problem doesn't worry me, but the second one does, look at this cut-down code...no apologies for it being contrived...if I wanted to hide it, I could do... :> LA 2,8-1 :> EX R2,EXMVC :> L R5,EXMVC :> OILF R5,X'00FF0000' :> OPEN (DCB2,OUTPUT,(R5)),MF=(E,HERE24O),MODE=24 :> EX R2,EXMVC :> ... :>HERE DC 8C'A' :>THERE DC 8C'B' :>* :>DCB1 DCB ... :>DCB2 DCB ... :>* :>HERE24O OPEN (DCB1,INPUT),MF=L :>EXMVC MVC THERE(0),HERE :> :>Using OPEN/CLOSE to subvert code sends this into another dimension :> :>I've been exchanging Emails with Mark Nelson (RACF Development) about this and have offered a solution, I can quite understand why IBM aren't keen on it :> :>1) The OPEN/CLOSE list structure must change :>The 'new' structure needs an 8-byte header :>eg. :>DC C'OPCL' eyecatcher :>DC X'mode bit' :>DC XL3'no. of entries' :> :>2) The OPEN/CLOSE SVC processors must be able to detect the 'old' and :> 'new' formats in order not to disturb existing code :> :>3) OPEN/CLOSE MF=E will have extra coding for the 'new' format only, to :> detect both mode and storage violation errors...setting an error code :> :>Whether this is worth doing is largely up to the user community, I would be worried if an innocent looking macro could subvert program code :> :>Your thoughts ? :> :>Melvyn Maltz. -- Binyamin Dissen <bdis...@dissensoftware.com> http://www.dissensoftware.com Director, Dissen Software, Bar & Grill - Israel
