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IEF_ALLC_UNLOAD — Allocation Event Installation Exit z/OS MVS Installation Exits SA23-1381-00 |
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Topics for This Exit Appear as Follows: The IEF_ALLC_UNLOAD exit is driven when a device is unloaded by Device Allocation outside of normal end-of-job or end-of-step device unload processing. It is invoked during processing such as VARY OFFLINE or UNLOAD commands. This exit is called before the unload event starts and after the unload is complete. It is intended for programs that need to perform pre-processing or post-processing for an unload event. If your program only needs to be notified of an unload occurring and does not need to perform pre- or post-processing, then ENF function code 25 should be used instead. Parameters describing the function are passed to the exit. These parameters are mapped by the IEFUNLXT mapping macro. Controlling the Exit Routine Through the Dynamic Exits FacilityIBM® has defined the Allocation Event installation exit to the dynamic exits facility. You can refer to the exit by the name IEF_ALLC_UNLOAD. You can use the CSVDYNEX macro to control this exit and its exit routines. You
can use the ADDABENDNUM and ABENDCONSEC parameters on the CSVDYNEX
REQUEST=ADD macro to limit the number of times the exit routine abnormally
ends before it becomes inactive. An abend is counted when both of
the following conditions exist:
By default, the system does not disable the exit routine. Replacing the Exit RoutineFor information about replacing a dynamic exit routine, see Replacing a Dynamic Exit Routine. Exit Routine EnvironmentThe
exit routine receives control in the following environment:
The parameter list contains information indicating which of the ENQs are obtained by another task on behalf of the unload process. Exit RecoveryThe exit routine should provide its own recovery. If the exit routine abnormally terminates, its recovery routine will get control. If the exit routine abnormally terminates, and the exit routine does not provide its own recovery, or the error percolates beyond the exit's recovery routine, a system recovery routine will get control and fail the allocation request. Whether or not the exit routine continues to be invoked depends on the abend processing of the dynamic exits facility. Exit Routine ProcessingMVS™ invokes the Unload Event exit routine or routines, if any are specified to the dynamic exits facility, whenever an unload event takes place. Using the Information
in the Parameter List: MVS passes
the address of a list of parameters to the exit routine. The parameters
contain the following information:
The exit routine can use the information in the parameter list. Because there is no action to be taken, the exit routine does not need to provide any response from the Unload Event exit. Programming ConsiderationsObserve
the following conventions when coding the IEF_ALLC_UNLOAD Exit routine:
Macro Instructions and Restrictions: Do not code the exit routine to invoke dynamic allocation. Entry SpecificationsThe system passes the address of the exit parameter list to the exit routine. Registers at Entry: The contents of the registers on entry to the exit are as follows.
Parameter Descriptions: Register 1 contains the address of the exit parameter list, which is mapped by macro IEFUNLXT Return SpecificationsMVS does not provide any field for a response; the exit does not return a valid value. Registers at Exit: Upon return from the exit processing, the register contents must be as follows.
Coded Example of the Exit RoutineThere is no coded example of this exit routine in SYS1.SAMPLIB. |
Copyright IBM Corporation 1990, 2014
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