@Peter is (of course!) correct. I just accepted your premise and went from there. You need a 24-bit GETMAIN for the DCB, but a separate DLL or anything like that is a way unnecessary over-complication.
I wrote a paper years ago on converting A/RMODE 24 DCB I/O programs to 31-bit. I will send you a copy, and I hereby offer a copy to anyone else who wants to write me off-list. It is not *directly* relevant -- it is about *converting* an existing DCB program to 31-bit -- but it does cover what needs to go where relative to the 24-bit line in the DCB world. Charles -----Original Message----- From: IBM Mainframe Assembler List [mailto:[email protected]] On Behalf Of Peter Relson Sent: Tuesday, July 2, 2019 4:52 AM To: [email protected] Subject: Re: C DLL Code from Assembler <snip> First of my Assembler code is RMODE31 So I anyway have to call something below the line to open to read to close </snip> It is not true that you have to call something below the line. Code doing OPEN and CLOSE can be RMODE 31, quite possibly needing to specify MODE=31. The DCB itself needs to be below 16M. Even exits via the DCBE can be above 16M. Peter Relson z/OS Core Technology Design
