Setting up the XPI environment

The exit programming interface (XPI) does not require the usual CICS® transaction environment, but you must set up a special exit programming environment before you can use any XPI calls.

If you are going to use any of the XPI functions in an exit program, you must include the following macro in your program, before you issue any XPI calls:

DFHUEXIT TYPE=XPIENV

The expansion of this macro provides the DSECTs that are used in all XPI calls. It also provides a list of register equates (R0 EQU 0, R1 EQU 1, and so on), that you can use in your exit program. The other fields generated by the macro are used by CICS to perform the XPI call processing. You must not use any of these fields: if you do so, your user exit program will have unpredictable results.

The user exit program must be in 31-bit addressing mode.