I have x11vnc
installed on my machine.
When I use x11vnc -create to start vnc server it automatically starts a new X session as a daemon. Then I was able to connect with a vnc client. And the DISPLAY always defaults to :20. But when I try to start X manually by typing X it tells me could not use display XXX(whatever I set DISPLAY to)
and so. The Arch Linux manpage says people always start a X session before they use a vnc server. How do I manually start a session?