Identifying the Installation-Written POST Exit Routine

When you build a mailbox using IXZXIXMB, you must identify a POST exit routine that is to receive control when JES XCF places a message in that mailbox. You must:

Provide the exit routine (POSTXIT= parameter on the IXZXIXMB macro) and specify its entry point.
Provide a data area that contains data required by the exit routine. If the data area is in a data space or in another address space, you must also provide the access list entry token (ALET) used to access the data. The ALET must be on the primary address space access list (PASN-AL).

The only function that this exit routine performs is posting the routine that is to receive the message that was placed into the mailbox. This posting action informs the receiving routine that there is a message in the mailbox.

When you create your POST exit routine, it must conform to certain MVS requirements and restrictions. Refer to POST Exit Routine for instructions for coding a POST exit routine.