C++ runtime classes are the foundation on which generated C++ code is built. Some of these classes such as the message buffer classes are for direct use in application programs. Others, such as the XSD type base classes, are used primarily by the XBinder as base classes for generated classes. The general categories of C++ built-in runtime classes are as follows:

A cursory description of these classes follows. For a full description, see the XBinder C/C++ Runtime Reference Manual.