This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages) This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: "GNUstep" – news · newspapers · books · scholar · JSTOR (January 2010) (Learn how and when to remove this message) This article is in list format but may read better as prose. You can help by converting this article, if appropriate. Editing help is available. (January 2012) This article relies excessively on references to primary sources. Please improve this article by adding secondary or tertiary sources. Find sources: "GNUstep" – news · newspapers · books · scholar · JSTOR (February 2011) (Learn how and when to remove this message) (Learn how and when to remove this message)
Developer(s)GNUstep Developers
Stable release
make 2.9.0, base 1.28.0, gui 0.29.0, back 0.29.0 / May 6, 2021; 2 years ago (2021-05-06)
Preview release
only in the SVN software repository
Written inObjective-C
Operating systemCross-platform
TypeWidget toolkit
LicenseGNU General Public License for the applications
GNU Lesser General Public License for the libraries.

GNUstep is a free software implementation of the Cocoa (formerly OpenStep) Objective-C frameworks, widget toolkit, and application development tools for Unix-like operating systems and Microsoft Windows. It is part of the GNU Project.

GNUstep features a cross-platform, object-oriented IDE. Apart from the default Objective-C interface, GNUstep also has bindings for Java, Ruby,[2] GNU Guile and Scheme.[3] The GNUstep developers track some additions to Apple's Cocoa to remain compatible. The roots of the GNUstep application interface are the same as the roots of Cocoa: NeXTSTEP and OpenStep. GNUstep thus predates Cocoa, which emerged when Apple acquired NeXT's technology and incorporated it into the development of the original Mac OS X, while GNUstep was initially an effort by GNU developers to replicate the technically ambitious NeXTSTEP's programmer-friendly features.


GNUstep began when Paul Kunz and others at Stanford Linear Accelerator Center wanted to port HippoDraw from NeXTSTEP to another platform. Instead of rewriting HippoDraw from scratch and reusing only the application design, they decided to rewrite the NeXTSTEP object layer on which the application depended. This was the first version of libobjcX. It enabled them to port HippoDraw to Unix systems running the X Window System without changing a single line of their application source. After the OpenStep specification was released to the public in 1994, they decided to write a new objcX which would adhere to the new APIs. The software would become known as "GNUstep".[4]

Software architecture

Illustrates software components of the Linux desktop stack like the display server, graphics control element libraries or graphical shells.


GNUstep contains a set of graphical control elements written in the Objective-C programming language.

The graphical user interface (GUI) of GNUMail is composed of graphics control elements. GNUMail has to interact with the windowing system, e.g. X11 or Wayland, and its graphical user interface has to be rendered. GNUstep's backend provides a small set of functions used by the user interface library to interface to the actual windowing system. It also has a rendering engine which emulates common Postscript functions. The package gnustep-back provides the following backends:


GNUstep inherits some design principles proposed in OPENSTEP (GNUstep predates Cocoa, but Cocoa is based on OPENSTEP) as well as the Objective-C language.

Other interfaces

In addition to the Objective-C interface, some small projects under the GNUstep umbrella implement other APIs from Apple:

As of February 2020, there are no projects that build the Swift programming language against the GNUstep Objective-C environment.


Here are some examples of applications written for or ported to GNUstep.[8]

See also: Category:Software that uses GNUstep

Written from scratch

Ported from NeXTSTEP, OPENSTEP, or macOS

Forks of GNUstep

Class capabilities

Foundation Kit

The Foundation Kit provides basic classes such as wrapper classes and data structure classes.

Application Kit

The Application Kit provides classes oriented around graphical user interface capabilities.

See also


  1. ^ Ported from NeXTSTEP. Recent builds, when built with libobjc2, can use a newer version ported from Mac OS X Snow Leopard
  2. ^ "GNUstep Developer Tools - RIGS". Retrieved 10 April 2018.
  3. ^ GScheme Archived 2005-12-18 at the Wayback Machine
  4. ^ "GNUstep History". Retrieved 10 April 2018.
  5. ^ "gnustep/libs-boron: Boron is the atom that comes before carbon". GitHub. GNUstep. 23 March 2019.
  6. ^ "gnustep/libs-corebase". GNUstep. 19 November 2019.
  7. ^ "gnustep/libs-quartzcore". GNUstep. 11 December 2019.
  8. ^ "Category:Applications - GNUstepWiki". Archived from the original on 23 March 2021. Retrieved 10 April 2018.
  9. ^ "GNUstep Objective-C Runtime 2.0". GitHub. Note: Microsoft's WinObjC project contains a friendly fork of this library that includes a work around for the incremental linking issue.