User Exits › How You Manage User Exits › Common Parameter List for All Exit Routines

Common Parameter List for All Exit Routines

All exit routines are invoked through a standard parameter list pointed to by register 1. The values are:

+0

Fullword containing the address of the parameter list of the exit routine. This is not used for initialization calls.

+4

Fullword containing the communication word of the exit routine. The content of this word may be set by the routine during its initialization call and is passed unchanged for all subsequent calls. This word is set to zero when the routine gets control over the first initialization call.

If CA MIM is restarted, then the value set during the first initialization call is passed during the second initialization, unless the z/OS system has been IPLed.

+8

Fullword containing flags used to pass status information to the routine. The high order bit of the first byte is set on X'80' for the initialization call. If the initialization call is being made after the restart of CA MIM without an intervening IPL, then the X'40' bit is set in the first byte as well.

+C

Fullword containing the global communication word set by the exit routine.

The UXPARM member of the CAI.CBTDMAC data set contains a DSECT mapping for this standard parameter list.

Note: For more information about a specific exit routine, see the appropriate Programming Guide.

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.