Hello, I'm trying to develop an extension module in C, but am having some difficulties. I thought about posting to the general python mailling list, but since it has to do with the C API I figured this was the correct location. My difficulty lies with subclassing a class provided by another external module. I have access to the structure definition, so I can determine the size fo the tp_basicsize member of the PyTypeObject structure. What I can't seem to determine is value for the tp_base element. This is my current "best guess". PyObject* superclass; superclass = PyObject_GetAttrString( module, "SuperClass" ); if ( !superclass ) return; type.tp_base = superclass->ob_type; Py_DECREF( superclass ); type.tp_new = PyType_GenericNew; if ( PyType_Ready( &type ) < 0 ) return; Unfortunately, I seem to be inheriting from the type object for SuperClass, and not from SuperClass itself. I would greatly appreciate some direction on this issue. Thank-you, ---------------------------------------- Robert Johnstone Simon Fraser University http://www.sfu.ca/~rjohnsto/