provided by other libraries, which in turn use Xlib. There are two kinds of such libraries: libraries built atop of the X Toolkit Intrinsics library (Xt), which provides support for widgets but does not provide any particular widget; specific widgets are provided by widget set libraries that use Xt, such as Xaw and Motif; libraries that provide widget sets using Xlib directly, without the Xt library, such as the X versions of GTK, Qt, FLTK and fpGUI. Applications using any of these widget libraries typically specify the content of the window before entering the main loop and do not need to explicitly handle Expose events and redraw the window content. The XCB library is an alternative to Xlib. Its two main aims are: reduction in library size and direct access to the X11 protocol. A modification of Xlib has been produced to use XCB as a low-level layer. References External links X.Org Foundation's official programming documentation, including most recent version of Xlib - C Language X Interface in several formats. A short tutorial on Xlib Manual pages for all Xlib functions Kenton Lee's pages on X Window and Motif A longer tutorial on Xlib Using Xlib for creating a screensaver module Application programming interfaces C (programming language) libraries X Window System Articles with example C code