>>A key question is: once the SVC Screening routine has gotten control, how >>does it then make sure that the "real" SVC routine gets control both in >>the right environment (locks included) and also with all the right data >>(potentially all 16 64-bit GRs and ARs at the time of the SVC issuance, >>with the PSW of the issuer)?
>Why would that be required? Because that is what the callee expects. As with any interface (and particularly one that involves a state change), if you violate the interface defined by the callee you may cause functional problems or create system integrity problems. The overriding requirement of anything that puts itself in the middle is to do no harm. As to your point about CICS "stealing" GETMAIN (my term), it would have to, at least, be able to differentiate GETMAINs done by its application from those done within the system that just happened to be under the same task. That in general is difficult at best to get 100% right. Peter Relson z/OS Core Technologhy Design ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
