>That's actually a trickier question than you might imagine!
I imagine it is! In my current job, I'm getting involved when standard application debugging techniques don't help anymore. I usually work with IPCS, so SYSMDUMPs and SVCDUMPs. We moved to Cobol V5.2 earlier this year, but I still need to find the content of Cobol variables in those dumps. The changes to how Working Storage is implemented, and the fact that this is mostly undocumented, makes it difficult. This is the real reason I'm trying to understand all this. Your comments are most welcome! > There are a number of cases: the case where your module consists of COBOL, > PL/I and assembler only and all other cases. All other cases include cases > where the COBOL run time support is implemented in a language other than the > above. These cases include OO COBOL, XML support and a few others. > > > In the second case (not pure COBOL), the C_WSA is loaded in exactly the same > way as it is for a C program. Basically, first the program is loaded and > then the C run time gets control. It determines that you want to start new > instance of this program (C_WSA is only used for RENT.) So it calls CEEPPOS > which is the actual routine that gets a WSA and initializes it. > This all happens before main is run. (Or, in the case of C++, before any > file scope statics are constructed.) Yes, this is well understood. > In the first case, your program starts and the COBOL bootstrap routine gets > control. That routine is called at the start of every PROGRAM. In most > cases, it checks a few things and returns. But for the first program in the > run unit, it does some work including ensuring that LE is up. Part of that > work is getting storage for the WSA. > All of this happens before the first user statement in the PROCEDURE DIVISION > is executed. > So, no matter how the C_WSA is loaded (by and LE routine or by the COBOL run > time) it is present before the first user written statement in the program is > executed. Yes, again well understood. > Which means that unless you're getting some sort of a trap during the COBOL > start up, you should always see the C_WSA somewhere in your storage. Yep, somewhere. But somewhere is not specific enough if you need to find the value of a variable at the time of the dump. > By the way, WORKING STORAGE is another area of complexity. In the case of > NOWSOPT (the default for V5) W-S items are directly in the C_WSA. In the > case of WSOPT (V6) W-S is separately allocated and the WSA contains a pointer > to that allocation. (Again, this is all done before the first user statement > is executed.) I really which there was a document describing all the variants in detail and how to find variables in a dump in each case. Lack of that document, I'm trying to find out step by step. You would seem to be able to be of great help for me on this quest. -- Peter Hunkeler ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
