User Exits › Exit Routine Programming Considerations › MIMINIXT Exit

MIMINIXT Exit

You can use the optional MIMINIXT exit routine to acquire and initialize a global exit communication area that can be shared among exit routines for any CA MIM facility. You can use this communication area to allow routines to share site-specific data, such as a predefined user table.

CA MIM calls the MIMINIXT exit routine once per startup and before the initialization call for any other routine. On entry, +C in the common exit parameter list is either zero or the previous value from when you last shut down CA MIM. The flag byte at +8 is always set to X'80'.

The address of the global data area that is acquired and initialized must be stored at +C in the common exit parameter list before the routine returns to CA MIM.

Follow these rules when coding the MIMINIXT routine:

• Preserve all registers except registers 0, 1, and 15.
• Consider the execution environment for all user-specified exit routines when issuing a GETMAIN request for a global data area.
• Note that CA MIM does not provide serialization for the updating of a global data area. The serialization inherent in the execution environment of the routine is the only serialization that occurs.
• Use the INITEXIT parameter on the MIMINIT statement to identify the appropriate load module for the MIMINIXT routine. If you do not provide the module name on the INITEXIT parameter, then CA MIM tries to load and activate module MIMINIXT.

  Note: Specifying MIMINIT INITEXIT=NONE causes CA MIM to bypass all MIMINIXT processing.

  The sample member named MIMINIXT in the CAI.CBTDSRC data set contains a sample MIMINIXT exit routine.