GDSX (Extended General Device Support) Manual

Design and Development
Extended General Device Support (GDSX) Manual—529931-001
2-43
Compiling
User code must source in certain sections of the DCCBDECS and EXTDECS0 files, as
well as the PEXTGDS file. (See User Code Declarations on page 2-17 for details.)
To access format 2 files greater than 4 GB, the user code must source in sections of
the DCCBDEC2 and PEXTGDS2 file.
User code must also source in the DCB and LCB control structures. There are four
ways to do this:
•
The standard declarations for these structures can be sourced in from the
templates section of either DCCBDECS or USKELDEC, an installed subvolume file
which contains these two structures.
•
If you want to modify the DCB control structure, you can change the USKELDEC
file as desired and source in its modified templates section at compile time.
•
If you are using either the USKELEX example program or the USKELEXC example
program for your user code, you source in the templates section of the
ULHDECSE file (in the installed subvolume), which contains the standard LCB
template and a modified DCB template.
•
If you are using the USAMPLE example program for your user code, you source in
the templates section of the ULHDECS file (in the installed subvolume), which
contains the standard LCB template and a DCB template modified for USAMPLE.
Compiling
When you compile your user code, the PEXTGDS file, sections of the DCCBDECS file,
and—if you modified the templates section of DCCBDECS—the USKELDEC (or
ULHDECSE, or ULHDECS) files are sourced in, and the resulting object code is
named USCODE. (To access format2 files of size greater than 4 GB, the user code
must source in sections of the DCCBDEC2 and PEXTGDS2 file. The resulting object
code is named USCODE2)
To facilitate the compiling and binding procedures, you can use UBUILD and UBIND
files. While in the subvolume where you wish to work, copy the UBUILD and UBIND
files from the installed subvolume.
Edit UBUILD to assign SSV1 to the installed subvolume, and assign SSV2 to
$SYSTEM.SYSTEM. If you have source files in the subvolume where you are
working, you can assign SSV0 to the subvolume.