1.2.37 $INTERFACES : Specify Interface type.

The {$INTERFACES} directive tells the compiler what it should take as the parent interface of an interface declaration which does not explicitly specify a parent interface. By default the Windows COM IUnknown interface is used. Other implementations of interfaces (CORBA or Java) do not necessarily have this interface, and for such cases, this directive can be used. It accepts the following three values:

Interfaces will descend from IUnknown and will be reference counted.
Interfaces will not have a parent and are not reference counted (so the programmer is responsible for bookkeeping). Corba interfaces are identified by a simple string so they are assignment compatible with strings and not TGUID.
Currently, this is COM.