Before learning how you can use the JES XCF exits and macros, it's important to understand how and when JES XCF relates to standard JES processing. Your use of the macros and exits will be based not only on what function they can provide your installation, but also whether they are available when you need them to affect JES communications.

To explain the interrelationship of JES and JES XCF processing, refer to JES initialization processing, JES message processing, and JES Termination Processing. Much of JES2 and JES3 processing is similar but, as appropriate, differences are noted in the following discussion of initialization, message, and termination processing.