facility-name

    Specifies an event facility. Valid facility-name keywords are as
    follows:

    ADA        If the event facility is set to ADA, the (SET,CANCEL)
               BREAK and (SET,CANCEL) TRACE commands recognize Ada-
               specific events as well as generic, low-level task
               events. (Ada events consist of task and exception
               events.)

               You can set the event facility to ADA only if the main
               program is written in Ada or if the program calls an
               Ada routine.
    THREADS    If the event facility is set to THREADS, the
               (SET,CANCEL) BREAK and (SET,CANCEL) TRACE commands
               recognize POSIX threads-specific as well as generic,
               low-level task events. All POSIX threads events are
               task (thread) events.

               You can set the event facility to THREADS only if
               the shareable image CMA$RTL is currently part of the
               program's process (if that image is listed in a SHOW
               IMAGE display).