Juha Korhonen wrote:

> I am trying to learn how to write new widgets to X but I dont know where
> to start. Does anybody know good books about X programming????

When I starting writing my own implementation of the Qt API (which is
progressing quite nicely), I started by searching Google for tutorials on
XLib programming. There are many good tutorials to show you how simple X
programs operate. Google's comp.windows.x archive is also invaluable.

The tutorials available on the web are more than adequate to get you going.