Storage overlays where you specify the length greater than the receiving fields length can be much worse to diagnose (MVC FLDA(L'FLDB),FLDB) because the fields that follow could be anything (e.g. pointers or offsets) which can cause additional overlays. You can have a cascade of overlays of which you might be looking at diagnostic information from the last overlay.
When the sender is too short, you only affect a single field that usually is not a pointer or offset. Much easier to diagnose because you have a smaller set of possible causes and you generally know the effects the field has. If IBM were to implement an MVC:2, then you would never have receiver too short because it should check the length. I personally don't need this instruction because I have a single program that builds messages and formats lines but I can see how others might want it. Regards, Jon Perryman. ________________________________ From: Tony Thigpen <[email protected]> To: [email protected] Sent: Tue, May 22, 2012 7:48:58 PM Subject: Re: MVC with 2nd operand length how is: MVC FLDA,FLDB (receiver too short) any worse than MVC FLDC,FLDD (sender too short)
