IBM SC33-1683-02 - Manual (Page 249)

UEPATTTK
The address of a doubleword containing a transaction token. Note
that some of the transaction manager XPI calls require this token to
identify the transaction that is being attached.
Return codes
UERCNORM
Continue attach processing.
XPI calls
The user exit can inquire on the transaction being attached, using the
UEPATTTK transaction token as input to the XMIQ
INQUIRE_TRANSACTION XPI call.
The exit can also set the total priority and TCLASS, using the XMIQ
SET_TRANSACTION XPI call.
Most of the XPI calls can be used, but with caution since typically this exit
is invoked under the TCP task. Thus it is advisable not to issue any XPI
calls that might cause the TCP task to wait.
Notes:
1. The following XPI calls can be useful for obtaining information that could be
used to modify the attach of a transaction:
INQUIRE_TRANSACTION
INQUIRE_MXT
INQUIRE_TCLASS
INQUIRE_TRANDEF
INQUIRE_SYSTEM
2. The fields UEPTRANID, UEPUSER, UEPTERM, and UEPPROG are common
to many of the domain global user exit points, and normally return values
associated with the current user task. In the case of XXMATT, however, the user
task that is being attached is not the current task when the exit is invoked. Until
task attach is complete, the current task is the CICS task that is performing the
attach.
When the task being attached is for a task started by an immediate START
command; that is, a START without an interval, the current task is the task that
issues the START command, and the fields contain values associated with that
task.
transaction manager domain exit
Chapter 1. Global user exit programs 217