1. Extra Prototypes

You'll need to provide two extra prototypes for a GeoUtils subclass - one for the geo_matrix_create() method, and one for the no_geo_request() method. These should match the types specified in XmP.h. From Trivial.c:

XmGeoMatrix trivial_matrix_create(Widget _w, Widget _from,
                                  XtWidgetGeometry *_pref);
Boolean trivial_NoGeoRequest(XmGeoMatrix _geoSpec);