IBM SC33-1683-02 - Manual (Page 97)

EXEC interface program exits XEIIN, XEIOUT, XEISPIN, and XEISPOUT
There are four global user exit points in the EXEC interface program:
XEIIN Invoked before the execution of any EXEC CICS application programming
interface (API) or system programming interface (SPI) command.
XEISPIN
Invoked before the execution of any EXEC CICS SPI command except:
v EXEC CICS ENABLE
v EXEC CICS DISABLE
v EXEC CICS EXTRACT EXIT.
The sequence is:
TRACE – XEIIN – XEISPIN – EDF – command
XEIOUT
Invoked after the execution of any EXEC CICS API or SPI command.
XEISPOUT
Invoked after the execution of any EXEC CICS SPI command except those
listed for XEISPIN.
The sequence is:
command – EDF – XEISPOUT – XEIOUT – TRACE
Note: Asynchronous processing of these exits may occur if the transaction is
suspended (for example, during file I/O wait). This situation may also occur
under CEDF because CEDF issues its own EXEC CICS commands between
the application’s XEISPIN and XEISPOUT exits.
If, for example, the same GWA is shared between the XEIIN and XEIOUT
exits, you must allow for the possibility of asynchronous processing, in order
to ensure integrity of the data and to prevent unpredictable results.
On entry to the exits, the exit-specific parameter UEPARG contains the address of
the command parameter list.
The command parameter list
The first parameter in the list points to a string of data known as argument 0. The
other parameters point to the values specified for the parameters passed on the
command.
Argument 0 begins with a 2-byte function code that identifies the command.
(Function codes are documented in Appendix A of the
CICS Application
Programming Reference manual and in Appendix B of the CICS System
Programming Reference manual.) The function code is followed by a 2-byte field
containing “existence bits” which indicate whether arguments are passed on the
command. For example, consider the command:
EXEC CICS LINK PROGRAM(‘MYPROG’)
Here, argument 0 begins with the function code X'0E02' (LINK). Existence bit 1 is
set, indicating that there is an argument 1 (namely, ‘MYPROG’).
EXEC interface program exits
Chapter 1. Global user exit programs 65