How to have more than one screen ?
 

I am getting setup info from X11 server, directly without Xlib or XCB but from sockets;
Is one problem: in structure I get field "Visual types count" was 119 whereas I got 122 VisualTypes.
Will be worse if will more than one screen. I don't know if will first screen, second screen, all visualtypes or first screen, visualtypes, second screen, visualtypes.
U want test it from more than one screen, how to have more than one screen ?

dual screens
 

To configure two screens install and run "xrandr". In Ubuntu you can find it in the "X11-xserver-utils package". there is also "arandr" or "lxrandr" (for LXDE), possibly others. Don't worry, it is pretty easy to use.