IBM SC33-1683-02 - Manual (Page 788)

The get-command exit
The purpose of the get-command exit is to read in command lines. If it is specified,
no commands are read from SYSIN.
On invocation, your exit routine must supply the address and length of a complete
command. It must return control with either the normal return code ‘UERCNORM’ or
with the code ‘UERCDONE’, signifying that it has no more commands to pass. After
it has processed each command, DFHCSDUP reinvokes the exit until return code
‘UERCDONE’ is received.
When invoked
Invoked multiple times, at the point where DFHCSDUP would otherwise
read commands from SYSIN.
Exit-specific parameters
UEPCMDA
Address of a fullword containing a pointer to a command
UEPCMDL
Address of a halfword containing the length of the command text.
The maximum length that can be specified is 1536 bytes.
Return codes
UERCNORM (X'00')
Continue processing.
UERCDONE (X'04')
No more commands to process. (This is equivalent to reaching
end-of-file on the SYSIN file.)
UERCERR
Irrecoverable error. This causes DFHCSDUP to terminate with a
return code of ‘8’.
XPI calls
Must not be used.
invoking DFHCSDUP from a user program
756 CICS TS for OS/390: CICS Customization Guide