Motif has a variety of widgets and gadgets, each designed to
accomplish a specific set of tasks, either individually or in
combination with others. Convenience functions create certain widgets
or sets of widgets for a specific purpose. xmCreatePushButton/4 in
the program above is an example of such a procedure.
The widgets are grouped into several classes, depending on the function of the widget. Logically, a widget class consists of the procedures and data associated with all widgets belonging to that class. These procedures and data can be inherited by subclasses. Detailed information on the properties of each widget and the procedures associated with it can be found in books on Motif.