X Windows, generally wondering
I'm still moderately new to linux and programming with/on/for it.
My question is generally, where does X Windows sit with regard to Qt and Gtk, and other varieties of GUI tools?
And if you please, in particular..
Do Qt, Gtk etc call Xlib, or work around it?
Is there any benefit being familiar with X Windows programming directly?
Do X Windows programs run on gnome, kde, etc?
Do linux developers care about Motif?