IBM SC34-6814-04 - Manual (Page 282)

UERCAQUE
Queue the allocate request.
UERCAPUR
Reject the allocate request with SYSIDERR.
UERCAKLL
Reject this allocate request with SYSIDERR. Purge all other
queued allocate requests and send an information message to the
operator console. CICS also returns SYSIDERR to all application
programs waiting on the purged allocate requests.
UERCPURG
Task purged during XPI call.
In the case of a successful allocate following the use of UERCAKLL on a
previous invocation of the exit, use one of the following:
UERCNORM
Resume normal operation of the IPCONN.
UERCAPUR
Reject the allocate request with SYSIDERR.
XPI calls
All can be used.
Using an XISQUE global user exit program
When the exit is enabled, your XISQUE global user exit program is able to check
on the state of allocate queues for IPCONNs in the local system. The parameter list
passed to the exit program on invocation provides data about a specific allocate
request and IPCONN.
Using the information passed in the parameter list, your global user exit program
can decide (based on queue length, for example) whether CICS is to queue the
allocate request. Your program communicates its decision to CICS by setting one of
the following return codes:
UERCAQUE
CICS is to queue the allocate request.
The total number of allocate requests currently queued against the connection
is provided in field ISR_CURRENT_QUEUED_ALLOCATES of the IPCONN
statistics record, which is addressed by the UEPCONST exit-specific parameter.
See DSECT DFHISRDS for details.
CICS also passes to the exit program, in field UEPQUELM, the value of the
QUEUELIMIT option of the IPCONN resource definition. If the queue limit has
not been reached, you can return control to CICS with return code
UERCAQUE.
UERCAPUR
CICS is to reject the allocate request, return SYSIDERR to the application
program, and leave the existing queue unchanged.
If the number of queued allocate requests has reached the limit set on the
QUEUELIMIT option of the IPCONN definition, you can request that CICS
rejects the request. However, you should first check whether the state of the
link is satisfactory. This means checking that the rate of allocation of sessions is
acceptable. Use the time the queue was started, the current time, and the total
260 Customization Guide