IBM SC33-1683-02 - Manual (Page 72)

DBCTL tracking program exits XXDFB and XXDTO
Exit XXDFB
When invoked
By the alternate CICS when it receives a message from the active CICS
indicating that connection to DBCTL has failed. The alternate and active
CICS systems are running in different MVS images, perhaps in different
central processing complexes (CPCs). More information about these exits is
provided in the
CICS IMS Database Control Guide.
Exit-specific parameters
UEPDBXR
Address of CICS XRF information for use with DBCTL. The CICS
XRF information can be mapped using the DSECT DFHDXUEP.
Return codes
UERCNOAC
Take no action.
UERCSWCH
Switch to the alternate DBCTL.
UERCABNO
Abend CICS without a dump.
UERCABDU
Abend CICS with a dump.
The return code ‘UERCNORM’ is not available for use at this exit point.
XPI calls
The following must not be used:
INQUIRE_MONITORING_DATA
MONITOR
TRANSACTION_DUMP
WRITE_JOURNAL_DATA.
DBCTL tracking program exits
40 CICS TS for OS/390: CICS Customization Guide