On the other hand, you can do useful work by knowing a very small subset of the total, and then incrementally increase your knowledge as the need arises. You build your applications from collections of widgets. The widgets collect input from the user. Motif is a collection of 40 or so widgets. Complete, nice-looking user interfaces written in X tend to be extremely long.
Motif tends to make the creation of user interface code shorter and much easier.
When the user moves or clicks the mouse, events are also generated. When events occur, the event loop calls the correct piece of code to handle them. A lot of this might not make much sense to you at the moment, and if that's the case don't panic. It will make more sense as we go through examples. So in these tutorials, I will start talking about purely Motif programs, as best I can.