Cics has a mini header and trailer to detect storage overlays so it would be 4k - a few bytes to if you wanted to exploit 4k boundaries without wasting storage
On Fri, Mar 28, 2025, 16:57 Mike Schwab < [email protected]> wrote: > CICS and IMS/TM have transaction definitions that include a workarea size. > Since you are getting the address in a register anyway, How about > standardizing on a 4K work area? > > On Fri, Mar 28, 2025 at 11:13 AM Rupert Reynolds <[email protected]> > wrote: > > > I sometimes wondered whether CICS did something like this for its "quasi > > reentrant" programs, but I never looked into it properly. > > > > Roops > > > > On Fri, 28 Mar 2025, 15:48 Richard Zierdt, < > > [email protected]> wrote: > > > > > When coding reentrant modules, one practice is to Obtain Storage > > (Getmain, > > > etc) and setup shop. This is well and good. > > > > > > But another technique would have the *caller*, who may be reentrant or > > > not, *provide* the savearea / workarea and pass the address of that > area > > > through typical R1 / address list linkage stuff. > > > > > > This would save Obtain / Getmain / Freemain calls. For a program that > > > gets called thousands of times, the overhead would add up. Yes, the > > > caller has to provide a workarea, and that may cost one Getmain, but > it's > > > only once. > > > > > > Say Program A calls reentrant Program B 10,000 times. If A provides > the > > > workarea, that saves 10,000 Getmain/Freemains in B. > > > > > > The concept seems to be used by the IEAMSXMP "POST" macro, which > wants a > > > 512-byte WORKAREA=. Well, why not get it yourself, IBM? Answer might > > be > > > to save overhead. (Yes, there may be other reasons). > > > > > > Any program could be reentrant without Getmains if callers provided > > > save/work areas (and the programs were written accordingly). > > > > > > Just a thought > > > > > > Richard Zierdt > > > > > > Confidentiality Warning/Avertissement de confidentialité: > > > > > > This message is intended only for the named recipients. This message > may > > > contain information that is privileged or confidential. If you are not > > the > > > named recipient, its employee or its agent, please notify us > immediately > > > and permanently destroy this message and any copies you may have. Ce > > > message est destiné uniquement aux destinataires dûment nommés. Il peut > > > contenir de l'information privilégiée ou confidentielle. Si vous n'êtes > > pas > > > le destinataire dûment nommé, son employé ou son mandataire, veuillez > > nous > > > aviser sans tarder et supprimer ce message ainsi que toute copie qui > peut > > > en avoir été faite. > > > > > > ---------------------------------------------------------------------- > > > For IBM-MAIN subscribe / signoff / archive access instructions, > > > send email to [email protected] with the message: INFO IBM-MAIN > > > > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to [email protected] with the message: INFO IBM-MAIN > > > > > -- > Mike A Schwab, Springfield IL USA > Where do Forest Rangers go to get away from it all? > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
