A “host application” is one that contains a main()function in its code, and provides the host services that an ObjectDBX or ObjectARX module needs.
Two types of host applications can take advantage of the interface provided by ObjectDBX. One type of host application is AutoCAD and the Autodesk products based on AutoCAD, with or without associated ObjectARX applications. The second type is a non-AutoCAD host application. A non-AutoCAD host application cannot load an ObjectARX application, and can take advantage only of the specific interfaces provided by ObjectDBX.
Licensed RealDWG developers can create host applications. See the autodesk.com Developer Center for more information.