Sets an event flag in a local or common event flag cluster.
    The condition value returned by $SETEF indicates whether the
    specified flag was previously set or clear. After the event flag
    is set, processes waiting for the event flag to be set resume
    execution.

    Format

      SYS$SETEF  efn

    C Prototype

      int sys$setef  (unsigned int efn);

  Additional Information (explode) :

• Argument