SXEmacs is a fork of the XEmacs

XEmacs

XEmacs is a graphical- and console-based text editor which runs on almost any Unix-like operating system as well as Microsoft Windows. XEmacs is a fork, based on a version of GNU Emacs from the late 1980s...

 text editor

Text editor

A text editor is a type of program used for editing plain text files.Text editors are often provided with operating systems or software development packages, and can be used to change configuration files and programming language source code....

.
It runs on many Unix-like

Unix-like

A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification....

 operating system

Operating system

An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

s, and is notable for features such as FFI

Foreign function interface

A foreign function interface is a mechanism by which a program written in one programming language can call routines or make use of services written in another. The term comes from the specification for Common Lisp, which explicitly refers to the language features for inter-language calls as...

 support, enhanced number types (similar to bignums in XEmacs 21.5), raw string regexps

Regular expression

In computing, a regular expression provides a concise and flexible means for "matching" strings of text, such as particular characters, words, or patterns of characters. Abbreviations for "regular expression" include "regex" and "regexp"...

, and an implementation of Pugh

William Pugh

William Pugh is the inventor of the skip list, the Omega test for deciding Presburger arithmetic, co-author of the static code analysis tool FindBugs, and was highly influential in the development of the current memory model of the Java language together with his PhD student Jeremy Manson.He is...

's skip list

Skip list

A skip list is a data structure for storing a sorted list of items using a hierarchy of linked lists that connect increasingly sparse subsequences of the items...

s. Any user can download SXEmacs as free software

Free software

Free software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...

 available under Version 3 of the GNU General Public License

GNU General Public License

The GNU General Public License is the most widely used free software license, originally written by Richard Stallman for the GNU Project....

.

History

On December 31, 2004, Steve Youngs (lead developer) announced the creation of SXEmacs on the emacs-devel and xemacs-beta mailing lists.

The software community generally refers to GNU Emacs, XEmacs

XEmacs

XEmacs is a graphical- and console-based text editor which runs on almost any Unix-like operating system as well as Microsoft Windows. XEmacs is a fork, based on a version of GNU Emacs from the late 1980s...

, SXEmacs (and a number of other similar editors) collectively or individually as emacsen or as emacs, since they all take their inspiration from the original TECO

Text Editor and Corrector

TECO is a text editor originally developed at the Massachusetts Institute of Technology in the 1960s, after which it was modified by 'just about everybody'...

 Emacs.

The reasons he cited for the fork were:

• a belief that XEmacs
  XEmacs
  XEmacs is a graphical- and console-based text editor which runs on almost any Unix-like operating system as well as Microsoft Windows. XEmacs is a fork, based on a version of GNU Emacs from the late 1980s...
  
  was too "broken" and unstable
• wanting to make radical changes
• wanting a development environment not embroiled in politics
• wanting more control over the project
• making it easier for developers to contribute and get involved.

SXEmacs and GPLv3

On November 25, 2007, patch-34 of the main 22.1.8 development branch was committed. This marked the start of a transition to GPLv3. This transition was completed the following day (November 26, 2007) with patch-37.