IBM SC33-1683-02 - Manual (Page 236)

contains FMHs, as specified by the FMH option on the associated
START command; or hexadecimal zeros otherwise.
UEPALSTC
Address of a 2-byte field containing the start code. This is "SZ" for
FEPI starts; otherwise it is "SD".
Return codes
UERCNORM
No other return codes are supplied. The value of the return code is
not inspected.
XPI calls
You can use:
INQ_APPLICATION_DATA
INQUIRE_SYSTEM
No other XPI calls should be used.
API and SPI commands
No EXEC CICS commands can be used.
Note: The XALTENF exit, used to handle the “terminal not known” condition, is
also invoked from the terminal allocation program. XALTENF is described on
page 208.
terminal allocation program exit
204 CICS TS for OS/390: CICS Customization Guide