In VisualAge Smalltalk V4.0, the class OSObject became an abstract class which should not be directly instantiated or subclassed. An OSObject subclass called OSPtr now contains the function previously available in OSObject. Additionally, OSPtr contains a subclass called AbtForeignOSObject which supports code page conversion. Existing applications that currently use OSObject subclasses or instances to share data with external functions need to be migrated to use OSPtr or another suitable OSObject subclass.