I don't see anything in the book. But as a shear guess, I would say that the code which implements the MODCB functionality most likely is passed a number of possible parameters to modify and thinks "zero means do not modify that particular parameter". I would guess that the AREA= remains whatever it was before the MODCB was executed. I guess you'd need to test it somehow.
On Thu, 2011-08-04 at 17:49 -0500, David de Jongh wrote: > I was looking at an assembler program today that (accidentally) passes a > null parameter to our common VSAM I/O routine as the target work area for a > GET request. > The common routine uses a set of predefined ACBs and RPLs, and does a MODCB > RPL to point to the caller's work area when a GET is requested. I'd have > thought there'd be a S0C4 or a VSAM error when the GET is issued, but > apparently this is not the case. > I don't see anything specific in the DFSMS manuals regarding the AREA= > operand on the RPL, so I assume VSAM simply decides it isn't present and > ignores it. > Opinions? Comments? > David de Jongh -- John McKown Maranatha! <><
