Structures, Styles, Callbacks, and Message Maps This section documents the structures, styles, and callback functions used by the Microsoft Foundation Class Library and the MFC message maps. In This Section Structures Used by MFC Provides links to the structures called from various member functions. Styles Used by MFC Provides links to the styles used when creating MFC objects. Callback Functions Used by MFC Provides links to the callback functions appearing in the MFC Library. Message Maps Describes the message mapping macros and CWnd message-map entries. Related Sections Class Library Overview Lists the classes in the MFC Library according to category. MFC Samples Provides links to samples that demonstrate using the MFC Library.