GNUstep is a

free software Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, no ...

implementation of the

Cocoa Cocoa may refer to: Chocolate * Chocolate * ''Theobroma cacao'', the cocoa tree * Cocoa bean, seed of ''Theobroma cacao'' * Chocolate liquor, or cocoa liquor, pure, liquid chocolate extracted from the cocoa bean, including both cocoa butter and ...

(formerly

OpenStep OpenStep is a defunct object-oriented application programming interface (API) specification for a legacy object-oriented operating system, with the basic goal of offering a NeXTSTEP-like environment on non-NeXTSTEP operating systems. OpenStep was ...

)

Objective-C Objective-C is a general-purpose, object-oriented programming language that adds Smalltalk-style messaging to the C programming language. Originally developed by Brad Cox and Tom Love in the early 1980s, it was selected by NeXT for its NeXTS ...

frameworks A framework is a generic term commonly referring to an essential supporting structure which other things are built on top of. Framework may refer to: Computing * Application framework, used to implement the structure of an application for an op ...

widget toolkit A widget toolkit, widget library, GUI toolkit, or UX library is a library or a collection of libraries containing a set of graphical control elements (called ''widgets'') used to construct the graphical user interface (GUI) of programs. Most widg ...

, and application development tools for

Unix-like A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-li ...

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...

s and

Microsoft Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...

. It is part of the

GNU Project The GNU Project () is a free software, mass collaboration project announced by Richard Stallman on September 27, 1983. Its goal is to give computer users freedom and control in their use of their computers and computing devices by collaborati ...

. GNUstep features a cross-platform, object-oriented IDE. Apart from the default

interface, GNUstep also has bindings for

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's List ...

Ruby A ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum ( aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sa ...

GNU Guile GNU Ubiquitous Intelligent Language for Extensions (GNU Guile) is the preferred extension language system for the GNU Project and features an implementation of the programming language Scheme. Its first version was released in 1993. In addition ...

and

Scheme A scheme is a systematic plan for the implementation of a certain idea. Scheme or schemer may refer to: Arts and entertainment * ''The Scheme'' (TV series), a BBC Scotland documentary series * The Scheme (band), an English pop band * ''The Schem ...

. The GNUstep developers track some additions to Apple's

to remain compatible. The roots of the GNUstep application interface are the same as the roots of Cocoa:

NeXTSTEP NeXTSTEP is a discontinued object-oriented, multitasking operating system based on the Mach kernel and the UNIX-derived BSD. It was developed by NeXT Computer in the late 1980s and early 1990s and was initially used for its range of proprieta ...

and

. GNUstep thus predates Cocoa, which emerged when

Apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, wh ...

acquired

NeXT Next may refer to: Arts and entertainment Film * ''Next'' (1990 film), an animated short about William Shakespeare * ''Next'' (2007 film), a sci-fi film starring Nicolas Cage * '' Next: A Primer on Urban Painting'', a 2005 documentary film Lit ...

's technology and incorporated it into the development of the original

Mac OS X macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac (computer), Mac computers. Within the market of ...

, while GNUstep was initially an effort by

GNU GNU () is an extensive collection of free software (383 packages as of January 2022), which can be used as an operating system or can be used in parts with other operating systems. The use of the completed GNU tools led to the family of operat ...

developers to replicate the technically ambitious NeXTSTEP's programmer-friendly features.

History

GNUstep began when

Paul Kunz Paul Kunz (December 20, 1942 – September 12, 2018) was an American Particle physicist and software developer, who initiated the deployment of the first web server outside of Europe. After a meeting in September with Tim Berners-Lee of CERN, he ...

and others at

Stanford Linear Accelerator Center SLAC National Accelerator Laboratory, originally named the Stanford Linear Accelerator Center, is a United States Department of Energy National Laboratory operated by Stanford University under the programmatic direction of the U.S. Departme ...

wanted to port HippoDraw from

to another platform. Instead of rewriting HippoDraw from scratch and reusing only the application design, they decided to rewrite the NeXTSTEP

object Object may refer to: General meanings * Object (philosophy), a thing, being, or concept ** Object (abstract), an object which does not exist at any particular time or place ** Physical object, an identifiable collection of matter * Goal, an ...

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 The X Window System (X11, or simply X) is a windowing system for bitmap displays, common on Unix-like operating systems. X provides the basic framework for a GUI environment: drawing and moving windows on the display device and interacting wit ...

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".

Software architecture

Free and open-source-software display servers and UI toolkits

Rendering

GNUstep contains a set of

graphical control element A graphical widget (also graphical control element or control) in a graphical user interface is an element of interaction, such as a button or a scroll bar. Controls are software components that a computer user interacts with through direct ...

s written in the Objective-C programming language. The

graphical user interface The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...

(GUI) of

GNUMail GNUMail is a free and open-source, cross-platform e-mail client based on GNUstep and Cocoa. It is the official mail client of GNUstep and is also used in Étoilé. It was inspired by NeXTMail (NeXT's Mail.app), the predecessor of Apple Mail. ...

is composed of graphics control elements. GNUMail has to interact with the

windowing system In computing, a windowing system (or window system) is software that manages separately different parts of display screens. It is a type of graphical user interface (GUI) which implements the WIMP (windows, icons, menus, pointer) paradigm for ...

, e.g.

X11 The X Window System (X11, or simply X) is a windowing system for bitmap displays, common on Unix-like operating systems. X provides the basic framework for a GUI environment: drawing and moving windows on the display device and interacting wi ...

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

. It also has a

rendering engine Rendering or image synthesis is the process of generating a photorealistic or non-photorealistic image from a 2D or 3D model by means of a computer program. The resulting image is referred to as the render. Multiple models can be defined ...

which emulates common

Postscript PostScript (PS) is a page description language in the electronic publishing and desktop publishing realm. It is a dynamically typed, concatenative programming language. It was created at Adobe Systems by John Warnock, Charles Geschke, Doug Br ...

functions. The package gnustep-back provides the following backends: * cairo – default backend using the

Cairo Cairo ( ; ar, القاهرة, al-Qāhirah, ) is the capital of Egypt and its largest city, home to 10 million people. It is also part of the largest urban agglomeration in Africa, the Arab world and the Middle East: The Greater Cairo metro ...

2D graphics library. * winlib – default backend on Microsoft Windows systems. Cairo and

Windows API The Windows API, informally WinAPI, is Microsoft's core set of application programming interfaces (APIs) available in the Microsoft Windows operating systems. The name Windows API collectively refers to several different platform implementations th ...

variants. * art – old (deprecated) backend on unix-like systems. Uses the vector-based PostScriptlike 2d graphics library

Libart Libart is a free software graphics library of functions for 2D graphics supporting a superset of the PostScript imaging model. Libart was designed to be integrated with graphics, artwork, and illustration programs. It is written in optimized C an ...

. *

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 ...

– old (deprecated) X11 backend.

Paradigms

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

language. *

Model–view–controller Model–view–controller (MVC) is a software architectural pattern commonly used for developing user interfaces that divide the related program logic into three interconnected elements. This is done to separate internal representations of infor ...

paradigm * Target–action *

Drag-and-drop In computer graphical user interfaces, drag and drop is a pointing device gesture in which the user selects a virtual object by "grabbing" it and dragging it to a different location or onto another virtual object. In general, it can be used to ...

* Delegation * Message forwarding (through NSInvocation)

Other interfaces

In addition to the Objective-C interface, some small projects under the GNUstep umbrella implement other APIs from Apple: * The Boron library aims to implement the Carbon API. It is very incomplete. * The CoreBase library is designed to be compatible with

Core Foundation Core Foundation (also called CF) is a C application programming interface (API) written by Apple for its operating systems, and is a mix of low-level routines and wrapper functions. Most Core Foundation routines follow a certain naming conventi ...

. It is not complete enough to for the Base (Foundation Kit) component to simply be a wrapper around it. * The QuartzCore library implements

Core Animation Core Animation is an animation graphics compositing framework used by macOS (Mac OS X Leopard and later), iOS, watchOS, and tvOS to produce animated user interfaces. Overview Core Animation provides a way for developers to produce animated user i ...

APIs. The Opal library implements Quartz 2D. , there are no projects that build the Swift programming language against the GNUstep Objective-C environment.

Applications

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

Written from scratch

* Addresses, an address/ contacts manager * Étoilé, a

desktop environment In computing, a desktop environment (DE) is an implementation of the desktop metaphor made of a bundle of programs running on top of a computer operating system that share a common graphical user interface (GUI), sometimes described as a graphica ...

, an

e-mail client An email client, email reader or, more formally, message user agent (MUA) or mail user agent is a computer program used to access and manage a user's email. A web application which provides message management, composition, and reception functio ...

* GNUstep Database Library 2, an

Enterprise Objects Framework The Enterprise Objects Framework, or more commonly simply EOF, was introduced by NeXT in 1994 as a pioneering object-relational mapping product for its NeXTSTEP and OpenStep development platforms. EOF abstracts the process of interacting with a re ...

clone *

GNUstepWeb GNUstepWeb is a development environment and an application server for Web Applications. It is characterized by strict separation of data storage, processing and user interface development. GNUstepWeb is based on GNUstep. Its goals are to be compa ...

, an application server compatible with WebObjects 4.x * Gorm, an

interface builder Interface Builder is a software development application for Apple Inc., Apple's macOS operating system. It is part of Xcode (formerly Project Builder), the Apple Developer developer's toolset. Interface Builder allows Cocoa (API), Cocoa and Car ...

* GWorkspace, a workspace and

file manager A file manager or file browser is a computer program that provides a user interface to manage files and folders. The most common operations performed on files or groups of files include creating, opening (e.g. viewing, playing, editing or pr ...

* Grr, an RSS feed reader *

Oolite Oolite or oölite (''egg stone'') is a sedimentary rock formed from ooids, spherical grains composed of concentric layers. The name derives from the Ancient Greek word for egg (ᾠόν). Strictly, oolites consist of ooids of diameter 0.25–2 ...

, a clone of ''

Elite In political and sociological theory, the elite (french: élite, from la, eligere, to select or to sort out) are a small group of powerful people who hold a disproportionate amount of wealth, privilege, political power, or skill in a group. D ...

'', a space simulation game with trading components * PRICE, imaging application * ProjectCenter, the Project Builder or

Xcode Xcode is Apple's integrated development environment (IDE) for macOS, used to develop software for macOS, iOS, iPadOS, watchOS, and tvOS. It was initially released in late 2003; the latest stable release is version 14.2, released on December 13, ...

equivalent. * TalkSoup, an

IRC Internet Relay Chat (IRC) is a text-based chat system for instant messaging. IRC is designed for group communication in discussion forums, called '' channels'', but also allows one-on-one communication via private messages as well as chat an ...

client *

Terminal Terminal may refer to: Computing Hardware * Terminal (electronics), a device for joining electrical circuits together * Terminal (telecommunication), a device communicating over a line * Computer terminal, a set of primary input and output dev ...

* Zipper, a

file archiver A file archiver is a computer program that combines a number of files together into one archive file, or a series of archive files, for easier transportation or storage. File archivers may employ lossless data compression in their archive formats ...

tool

Ported from NeXTSTEP, OPENSTEP, or macOS

* Adun
BioCocoa
*

Chess Chess is a board game for two players, called White and Black, each controlling an army of chess pieces in their color, with the objective to checkmate the opponent's king. It is sometimes called international chess or Western chess to disti ...

Cenon

EdenMath
* Eggplant *

Emacs Emacs , originally named EMACS (an acronym for "Editor MACroS"), is a family of text editors that are characterized by their extensibility. The manual for the most widely used variant, GNU Emacs, describes it as "the extensible, customizable, s ...

* Fortunate *

Gomoku ''Gomoku'', also called ''Five in a Row'', is an abstract strategy board game. It is traditionally played with Go pieces (black and white stones) on a Go board. It is played using a 15×15 board while in the past a 19×19 board was standard. Be ...

* NeXTGO
PikoPixel
*

TextEdit TextEdit is an open-source word processor and text editor, first featured in NeXT's NeXTSTEP and OPENSTEP. It is now distributed with macOS since Apple Inc.'s acquisition of NeXT, and available as a GNUstep application for other Unix-like ope ...

TimeMon

Forks of GNUstep

Universal Windows Platform Universal Windows Platform (UWP) is a computing platform created by Microsoft and first introduced in Windows 10. The purpose of this platform is to help develop universal apps that run on Windows 10, Windows 10 Mobile (discontinued), Windows 1 ...

, which includes a

WinObjC Universal Windows Platform (UWP) is a computing platform created by Microsoft and first introduced in Windows 10. The purpose of this platform is to help develop universal apps that run on Windows 10, Windows 10 Mobile (discontinued), Windo ...

suite consisting of various parts of GNUstep and

Microsoft Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washing ...

's own implementations of things like the

Cocoa Touch Cocoa Touch is the application development environment for building software programs to run on iOS for the iPhone and iPod Touch, iPadOS for the iPad, watchOS for the Apple Watch, and tvOS for the Apple TV, from Apple Inc. Cocoa Touch provide ...

API.

Class capabilities

Foundation Kit

The

Foundation Kit The Foundation Kit, or just Foundation for short, is an Objective-C framework in the OpenStep specification. It provides basic classes such as wrapper classes and data structure classes. This framework uses the prefix NS (for NeXTSTEP). It is a ...

provides basic classes such as wrapper classes and data structure classes.

Application Kit

The

Application Kit AppKit (formally Application Kit) is a graphical user interface toolkit. It initially served as the UI framework for NeXTSTEP. Along with Foundation and Display PostScript, it became one of the core parts of the OpenStep specification of APIs. L ...

provides classes oriented around

capabilities.

References

External links

GNUstep.org
project homepage
GNUstep Applications and Developer TutorialsThe GNUstep Application Project

FLOSS Weekly Interview with Gregory Casamento and Riccardo Mottola from GNUstep
*GNUstep o
DebianMacPortsNEXTSPACE desktop environment, based on GNUstep
SONY SNAP Framework based on GNUstep
(project is "currently on hold")--> {{DEFAULTSORT:Gnustep Compatibility layers Cross-platform free software Free software programmed in Objective-C GNU Project software NeXT Software that uses Cairo (graphics) Widget toolkits X Window System