On Alpha and Integrity server systems, establishes a request for
    notification when an OpenVMS system event occurs.

    Format

      SYS$SET_SYSTEM_EVENT  event ,astadr ,astprm ,acmode ,flags

                            ,handle

    C Prototype

      int sys$set_system_event  (unsigned int event, void

                                (*astadr)(__unknown_params), int

                                astprm, unsigned int acmode, unsigned

                                int flags, struct _generic_64 *

                                handle);