An application developer can use object handlers to introduce customized features into implementations of linked and embedded objects. When an object handler exists for a class of object, the object handler supplants some or all of the functionality that is usually provided by the client library and the server application. The object handler can take specialized action for any of the functions it intercepts. The object handler passes functions that it does not take action on to the client library, which then implements the default processing for that class.
An application might use an object handler to render Native data as the presentation data for an object, instead of using metafiles or bitmaps. Object handlers could also be used to implement special behavior when an object is opened.