I played with the approach you suggest and abandoned the effort. Too hard, and
too likely to break.
What I did do that worked was code a number of atomic assembler routines that
could be passed a DCB that was kept in an area that I malloc or new in C or
C++. One of those routines was
int MAKEDCB(void *DCBarea, const int DCBareaLen, const char *DCBtype, const
char DDname[8]);
It constructs a DCB in the C/C++ allocated area by moving in a model. DCBtype
is, e.g., "BPAM". Other routines are, e.g.,
int OPNDCBIN(void *DCBarea); // OPEN a DCB for input
Charles
-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf
Of Larry Slaten
Sent: Wednesday, July 14, 2021 7:45 AM
To: [email protected]
Subject: Mixing C/C++ with LE-conforming IBM HLASM
I am attempting to use the C/C++ FOPEN function to open a SYSLIB DD
pointing to a concatenation of executable libraries. Then extract the
DCB address so that I can use it to populate the LOAD and BLDL macro.
This would make it easier to keep the root program RENT. I realize that
I can code the DCB in the root assembler program and do what is
necessary to keep the program RENT. But, using the C/C++ functions
would make it simpler. I have used the FOPEN function to open the data
set, retrieved the file pointer. The file pointer points to another
31-bit address. I have dumped the storage around that 31-bit address, it
still doesn't look like a DCB. I do see "SYSLIB" at +84 bytes, so I
appear to be close to the answer. Does anybody know to obtain the DCB
address using the file pointer returned by FOPEN?
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