This chapter provides reference information necessary to code each of the JES XCF exits:

• IXZXIT01 - Transport Exit
• IXZXIT02 - Receive Exit
• IXZXIT03 - Attach/Detach Exit.

Each exit description provides:

• The purpose of the exit and how your installation can use the exit to modify processing of JES XCF.
• The parameter list that is passed to the exit and how to map the parameter list.
• The environment that exists when the exit receives control:
  • Address space in which the exit runs
  • Addressing mode (AMODE)
  • Address space control mode (ASC mode)
  • Authorization
  • Cross-memory mode
  • Dispatchable unit mode
  • Interrupt status
  • JES environments
  • Locks held at entry
  • Residency mode (RMODE)
  • Storage attributes (pageable and key)
• Register usage:
  • Content when the exit receives control
  • Content when the exit returns to its caller.
• How the exit communicates with its caller.
• Restrictions or requirements that affect the design of your exit routine.
  • JES or MVS services that the exit cannot use
  • Subpool usage requirements and restrictions
  • Maximum message lengths
  • Recovery responsibilities.