Wikipedia
Xlib
Xlib (also known as libX11) is an X Window System protocol client library written in the C programming language. It contains functions for interacting with an X server. These functions allow programmers to write programs without knowing the details of the protocol. Few applications use Xlib directly; rather, they employ other libraries that use Xlib functions to provide widget toolkits:
- X Toolkit Intrinsics (Xt)
- Athena widget set (Xaw)
- Motif
- FLTK
- GTK+
- Qt (X11 version)
- Tk
- SDL (Simple DirectMedia Layer)
- SFML (Simple and Fast Multimedia Library)
Xlib appeared around 1985, and is currently used in GUIs for many Unix-like operating systems. The XCB library is an attempt to replace Xlib. While Xlib is still used in some environments, modern versions of the X.org server implement Xlib on top of XCB.