My Fellow MI geeks:Thanks for the suggestions; I ended up trying a *USRQ, and it turned out to be easier to deal with than I'd imagined.
Now, I'm trying to append a group of records (the exact number unknown at compile time) to a physical file, while keeping all other jobs out of the file (so that there's no chance of two jobs interleaving their blocks of records). So I tried the ILE C front-end for the LOCK MI instruction, passing it a system pointer to the file, and it blew up in my face with a Sec40 violation.
Can somebody explain what's going on here?What do I need to do? Am I stuck with having to shell out ALCOBJ and DLCOBJ CL commands? Or is there a cheaper way?