Override Modifiers
The Override keyword for the BEGFUNC , BEGPROP , BEGSR and DCLEVENT commands control how properties and methods are overridden in derived classes. *NONE is the default, which specifies that none of the override options are available for properties and methods. The other options are *MUSTOVERRIDE, *NOTOVERRIDABLE, *OVERRIDABLE, and *OVERRIDES.
The Override (** ***NOTOVERRIDABLE) option specifies that a property or method cannot be overridden in a derived class. You can use the *NOTOVERRIDABLE option when you do not want to allow an overridden method to be overridden again in a derived class.
Properties and Methods defined with the Override(*MUSTOVERRIDE) option have no implementation in the base class and must be implemented in derived classes before it can be used.
The Override(*OVERRIDABLE) option specifies that a property or method can be overridden in a derived class.
The Override(*OVERRIDES) option specifies that a property or method overrides a member inherited from a base class. You can use the *NOTOVERRIDABLE and *MUSTOVERRIDE modifiers to control how properties and methods are overridden in derived classes.