Where to learn X11 and XCB?

Question

I want to create a software that requires X11 render window that is stacked on the top and grabs the keyboard and mouse(just like a screen locker) but all I could find was a shallow documentation with very few examples. How shall I proceed?

Answer 1

After researching for a little a while, I decided to answer the question myself.

The the X11 manual at sbin.com is a very good one and contains detailed explanation and examples.

I also found the folks at #xcb irc challel at irc.freenode.com very cooperative and knowledgeable. They suggested me to read code written in X11 like xscreensaver and others. That should get me started.