IBM SC33-1683-02 - Manual (Page 628)

The parameter list contains the following information:
DBUREQT
Request Type. The function code has one of the following values:
DBUCONN (X'01')
Connected
DBUDISC (X'02')
Disconnected.
DBUREAS
Reason for Disconnection. Contains flags:
DBUMENU (X'01')
Disconnected from menu
DBUDBCC (X'02')
Checkpoint Freeze input to DBCTL
DBUDRAF (X'03')
DRA Failure has taken place
DBUDBCF (X'04')
DBCTL Failure has taken place.
DBUSUFF
DRA startup table suffix.
DBUDBCTL
DBCTL identifier.
The sample program and copy book
The source-code of the supplied CICS–DBCTL interface status program,
DFHDBUEX, is provided, in assembler language only, in the
CICSTS13.CICS.SDFHSAMP library. A corresponding copy book, DFHDBUCA, that
maps the communication area, is in CICSTS13.CICS.SDFHMAC.
The sample program checks for the presence of the input parameters (passed in
the communication area). If these do not exist, control returns to the calling
program.
The type of request (CONNECTION|DISCONNECTION) is then determined, and a
branch is taken to the appropriate function routine (CONPROC|DISPROC).
DBUSHEAD DS OCL4 Standard Header
DBUREQT DS CL1 Function Code
DBUCOMP DS CL2 Component Code Always "DB"
DBURESV DS CL1 Reserved
DBUREAS DS CL1 Reason for disconnection
DBUSUFF DS CL2 DRA startup table suffix
DBUDBCTL DS CL4 DBCTL identifier
Figure 49. The DFHDBUEX communication area
the CICS–DBCTL interface status program
596 CICS TS for OS/390: CICS Customization Guide