IBM SC33-1683-02 - Manual (Page 190)

Program control program exits XPCREQ, XPCREQC, XPCFTCH,
XPCHAIR, XPCTA, and XPCABND
There are six user exit points in the program control program.
XPCREQ and XPCREQC
XPCREQ is invoked by the EXEC interface program before a link request is
processed. If the request is a distributed program link, the XPCREQ exit is driven
on both sides of the link; that is, in both the client and the server regions. The exit
program is passed the address of the application’s parameter list (in UEPCLPS),
and can modify this as required. For example, you can use this exit to modify the
SYSID at the time of a distributed program link request. One way you can achieve
this is to write an application program to manage a list of SYSIDs in a global work
area (GWA). The global user exit program can obtain access to the GWA, and use
the information stored there to redirect DPL requests.
XPCREQC is invoked after the link request is completed. You can use this exit to
pass back a response to the application via the EIBRESP or EIBRESP2 fields.
Such responses could be used to keep status information about a link request
up-to-date. For example, if a link request fails because a connection is unavailable,
XPCREQC could set EIBRESP=500 (a response code not used by CICS) to
indicate the failure, enabling the application, in conjunction with the other exit,
XPCREQ, to determine a suitable course of action.
Exit XPCREQ
When invoked
By the EXEC interface program before a link request is processed.
Exit-specific parameters
UEPCLPS
Address of the command parameter list.
UEPPCTOK
Address of a 4-byte token to be passed to XPCREQC. This allows
you, for example, to pass a work area to exit XPCREQC.
UEPRCODE
Address of a 6-byte hexadecimal copy of EIBRCODE.
UEPRECUR
Address of a halfword recursion counter. The counter is set to 0
when the exit is first invoked, and is incremented for each recursive
call.
UEPRESP
Address of a 4-byte copy of EIBRESP.
UEPRESP2
Address of a 4-byte copy of EIBRESP2.
UEPTSTOK
Address of a 4-byte token that is valid throughout the life of a task.
See “Using the task token UEPTSTOK” on page 163.
UEPRSRCE
Address of an 8-character copy of the EIB resource value,
EIBRSRCE.
program control program exits
158 CICS TS for OS/390: CICS Customization Guide