X11

The X Windowing System is widely used on Linux as the layer that 
coordinates drawing to the screen by providing windows. It also delivers 
events such as mouse and keyboard input from the kernel to applications. It 
is designed to run as a server that can be contacted through a specific 
protocol. The client's side of the protocol is implemented by libraries 
such as the old Xlib or the more modern XCB. Applications can use these to 
create windows and draw to them. However, typically most developers will 
choose to use a GUI library such as GTK+ (which has an X11 backend) 
instead.

Website: http://www.x.org/, http://xcb.freedesktop.org/
Platforms supported: Linux
Headers to include: X11/*.bi

