Xlib, how to make an application draw directly on the root window?

Question

How do I make an application draw directly on the root window? For example I want to print some line on the root window, like conky does. How do I do this using Xlib in C/C++?

Answer 1

Try getting the root window handle by calling XRootWindow function. Probably, you are already doing this before creating your other windows. Then use the XCreateGC to create graphics context. After that, render to the root window as you would usually do using XLib.