The parameter list that the system passes to the configuration change exit routine is mapped by the IOSDDCCD mapping macro, and its address is pointed to by GPR 1. The parameter list includes information about the change that occurred, such as the specific devices being added, modified, or deleted.
For complete field names and lengths, offsets, and description of the fields mapped by the IOSDDCCD mapping macro, see z/OS MVS Data Areas in the z/OS Internet library.