Last updated 8 September 2001 Please send corrections to gnustep-maintainer@gnu.org.
GNUstep is the Free Software Foundation's effort to implement NeXT Software Inc.'s (now Apple Inc.) OpenStep Standard. The project is not finished, however some components are useable now.
The GNUstep project consists of the following sub-projects:
OpenStep is an Application Programming Interface (API) for creating applications using the Objective C language. It was published by NeXT Computer Inc. in 1994.
OpenStep consists of three parts: the `FoundationKit', a library of non-graphical objects; the `AppKit', a library of objects usful in creating graphical applications; and `Display Postscript', an interface for drawing to the screen using the PostScript graphics language.
You can obtain a copy of the OpenStep standard from the GNUstep web site http://www.gnustep.org or it's mirror sites.
Well tested current builds:
Ix86/GNU-Linux PPC/GNU-Linux
Recent builds -
Ix86 Unixware-2.? Ix86 FreeBSD-3.0 (ELF) Ix86 OpenBSD-2.4 (static libraries) Sparc SUNOS-4.1.3 PowerPC GNU/Linux
Probably a few days porting to any other Unix system where current gcc/egcs compilers and gdb debugger work. See the GNUstep-HOWTO file or http://www.gnustep.org/information/machines_toc.html for more machines.
The primary targets for GNUstep are free 'Unix' platforms such as GNU/Linux.
That being said, the base library should run on Windows-NT,98 with the Cygwin unix emulation library from Cygnus (http://sourceware.cygnus.com/cygwin/) or the MinGW libraries. At present there are a few problems with networking (Distributed Objects) support, but the library is believed to work.
The gui library needs a win32 backend library to work under Windows-NT. The backend library is a thin layer that converts the GNUstep methods to handle drawing of GUI elements to calls to the win32 api. This is a project looking for a volunteer.
The application-wrapper used for GNUstep already allows for multiple binaries to be stored for different systems, so you should be able to write once, deploy anywhere.
You can use GNUstep with GNOME and/or KDE. GNUstep displays on top of X11. You can still do programming in C (since Objective-C is just a superset of C), and when (if?) GCC gets around to it, you'll be able to mix C++ and Objective-C code in the SAME file.
GNUstep, is much more than a window manager or desktop environment. It frees you to develop cross-platform applications without the work of developing an OS independent framework from scratch. It gives you lots of basic functionality, from Font Panels to Unicode strings to Distributed Objects.
No. GNUstep applications provide their GUI via the OpenStep API, which provides fully object-oriented access to GUI manipulation.
The object-oriented nature of the libraries and language make it much easier for new users to create their own subclasses rather than simply using the supplied widgets as in other frameworks.
Yes and No - The GNUstep architecture provides a single, platform-independent, API for handling all aspects of GUI interaction (implemented in the gstep-gui library), with a backend architecture that permits you to have different display models (display postscript, X-windows, win32, berlin ...) while letting you use the same code for printing as for displaying. Use of GTK in the frontend gui library would remove some of those advantages without adding any.
That being said, a backend library could be implemented using gtk if anyone wanted to do so. Since the frontend library handles most of the work involved in implementing the OpenStep API, the backend is a relatively thin layer and the advantages of GTK over direct xlib or win32 calls is likely to be minimal. If/when GTK is ported to more systems, a backend written using it could be a valuable asset - volunteers are, as always, wecome.
Use gcc-2.8.1 or later, from any GNU ftp site or, on some platforms you must use egcs-1.1.1 or later, from http://egcs.cygnus.com/
That depends ...
If you only want to use the database package - gnustep-db, you can use either the gnustep base library or libFoundation.
If you want to develop/use GNUstep gui applications, you must use the gnustep-base library since libFoundation is (13-Feb-2000) missing much essential functionality.
Good question. Read the tutorials at the GNUstep web site. Also, use the makefiles in the libraries, tool directories, and test applications as examples.
Get the HOWTO from http://www.gnustep.org/resources/documentation/GNUstep-HOWTO Get the latest release from ftp://ftp.gnustep.org. If you're really adventurous, get the latest snapshot by anonymous ftp from ftp://ftp.gnustep.org:/pub/daily-snapshots
Use anonymous CVS to keep up to date - instructions are in the HOWTO.
You are presumably under the misapprehension that GNUstep is some sort of window manager.
It isn't.
GNUstep is a whole load of things - primarily a set of libraries for developing software.
At present, it's those libraries, plus various command-line based support tools and service providing daemons. In the future, it will be the libraries, plus the support tools, plus various GUI development tools, a GUI desktop/workspace application etc.
At no stage will you ever 'run' GNUstep - you will run applications and tools and will make use of it's services (though at some point you may well find packages distributed as 'GNUstep' systems in the way that you get 'Linux' systems packaged today).
Current tools are -
The makefiles package To make building GNUstep tools and apps simple. The 'openapp' script To start up a GUI application from the command line. The defaults tools To read, create, delete, and modify user defaults from the command line. The name server To permit applications and tools to locate each other and communicate. The pasteboard server To permit cut-and-paste, drag-and-drop, and to let applicationsm and tools transparently provide services to each other. The distributed notification center To permit applications and tools to be notified of arbitrary external events. The 'make_services' program To locate (and cache information about) applications that are willing to provide services to other applications. The 'set_show_service' program A command-line utility to determine what services an application should be permitted to offer on it's 'services' menu.
If you want to see a sample GUI application running you need to build GNUstep and look at the example applications in the gstep-examples package. Build 'Finger' or 'Ink' and start it with 'openapp Finger.app' or 'openapp Ink.app'
To look best - use WindowMaker (the currently preferred GNUstep window manager) as your window manager.
See http://www.gnustep.org/ - the main web site.
It's usable now (for an experienced developer). Releases are made about every six months. However, if you are a serious developer, it's probably best to use the latest snapshots. See the GNUstep web site for a release schedule.
gstep-make does pretty much what the makefiles in NeXTstep do. gstep-base (Foundation) stuff should work fine for almost all projects. gstep-db is only EOF-1.0 compatible but should work ok. gstep-gui (AppKit) is usable with the xgps backend, and you would probably have to fix some things in the gui library. Cut-and-paste works, services work, drag-and-drop works, the NSText classes partially work. gstep-xgps basic functionality is quite usable. gstep-xdps is mostly usable. DGS (Display Ghostscript) is usable but slow.
You can't run these programs on GNUstep, but if you have the source code for the programs, you should be able to port them to GNUstep and compile them. Whether or not you will be able to run them depends on how complete GNUstep is at the time.
It is probably easy for simple programs. You'll have to use nfmake http://karl.nfox.com to translate the PB.prject file to GNUstep Makefiles, or rewrite the Makefiles yourself. You will also have to translate the NIB files (if there are any) to GNUstep model files using the nib2gmodel program (from ftp://ftp.gnustep.org/pub/gnustep/dev-apps).
There is an Interface Builder for GNUstep called Gorm, but it is in alpha release, so it may not work perfectly. You can get it from the GNUstep CVS repository (cvs -z3 checkout Gorm). The Project Manager ProjectCenter is also new.
No - NeXT/Apple never documented their nib format, so GNUstep supports both the 'gmodel' format (which stores information as text (property-lists) and can therefore be edited 'by hand') and binary archive format (which can be edited by Gorm). There IS a conversion tool that can be compiled under OPENSTEP to convert OPENSTEP nib files to GNUstep gmodel files.
Well, GNUstep implements the OpenStep API, not the old NeXTstep API but, Yes - once the gui library is complete, OpenStep or MacOS-X code should work without translation under GNUstep.
Yes - gstep-base already contains the documented changes in the Foundation library. GNUstep aims to be compatible with both the OpenStep specification and with MacOS-X It should be easy to write an application that compiles cleanly under both GNUstep and Yellow Box.
Gnustep is aiming for something like the NeXTstep-3.3 look and feel This is mostly determined by the gui backend library. In the case of the two existing backends (xdps and xgps), both are designed to look like NeXTstep/OPENSTEP. If someone wants to write a backend with a different look, they can. This would only be a few man-months work.
that one could on the NeXT?
No - at present the GNU compiler (gcc or egcs) does not support "Objective-C++" There are no specific plans to make it do so, but any volunteers to do it would be welcome.
Yes. The GNustep Java library/bridge called JIGS is available now. JIGS is a free (LGPL) Java Interface for GNUstep; it can automatically wrap Objective-C libraries based on GNUstep making them accessible directly to the Java programmer as if they were Java libraries. As a side effect, it is also possible to use the whole engine in the reverse way: JIGS provides a high level API to allow Objective-C programmers to start java virtual machines inside GNUstep Objective-C code and access java objects in the java virtual machine transparently, as if they were objective-C objects.
No - GNUstep uses the X-windows display postscript extension - the interface to that is not the same as the interface to the OPENSTEP/MacOS-X windows server. While someone could write a backend library to provide the interface, nobody has bothered to date.
Also - there is no known recent port to OPENSTEP of the base library.
1. Write/debug library code 2. Write documentation 3. Update the TODO list and library headers 4. Write applications
Some general advice -
Let people know what you are doing. Break your project up into the smallest units you can. Feed back frequent updates to the maintainers. Ask questions in the discussion mailing list.
Do remember that any changes beyond a few lines of code (or documentation) require a disclaimer or copyright assignment to the Free Software Foundation before they can be incorporated into the project. Get in touch with the maintainer of the library you are working on about this.
Don't start with large-scale reorganisation of anything - instead, get a general idea in mind of what you want to do, and proceed as much as possible with incremental changes that don't break anything - that way you can make those incremental changes available to the rest of the community at frequent intervals.
Don't be afraid to give up - there is no shame in finding out that you have take on too large/complex a project. It's much better to 'resign' and take on a smaller job than to just stop without telling anyone.
There is plenty of unimplemented stuff in the gui library and backend libraries that volunteers can work on - just browse through the code and see if it conforms to the documentation.
Specific tasks are noted in the developers section on the www.gnustep.org website.
Once you have coded something, you could always write a testcase and documentation for it :-)
Our documentation format is called gsdoc, which is an SGML format for Objective-C documentation in the same vein as XML. We are also trying to use Autodoc to self document source code. The gsdoc translator is included with the base library.
Newcomers could write documentation for individual classes by comparing the OpenStep specification, the MacOS-X documentation, and the GNUstep source. Documentation should clearly note where individual methods are specific to OpenStep, MacOS-X or are GNustep extensions.
More experienced people could write documentation on general programming topics, and tutorials for new users.
Anyone willing to write documentation, either tutorials for using GNUstep, or reference documentation for individual classes, should either write it in gsdoc or as plain ascii text for someone else to format into gsdoc.
GNUstep documentation should have copyright assigned to the Free Software Foundation.
The task list (http://www.gnustep.org/developers/tasks.html) is supposed to tell people what jobs are waiting to be done.
One job of major importance that pretty much anyone can do is to look for jobs to add to the task list. In the case of methods from the OpenStep specification or the MacOS-X documentation not being present in the GNustep libraries, it is also helpful to add the method prototypes to the library header files.
At the moment, send changes to Adam Fedor fedor@gnu.org or Richard Frith-Macdonald richard@brainstorm.co.uk
We are hoping to have a system where people can update the list directly.
A beginner can look through the MacOS-X documentation, the OpenStep specification and the GNUstep source and contribute TODO items.
If a class or method is in MacOS-X and OpenStep but is not in GNUstep - it's a high priority TODO and should at least be added to the GNUstep headers and a dummy version added to the source with a FIXME comment.
If a class or method is in MacOS-X but not OpenStep or GNUstep -
it's a low priority TODO. It should be added to the GNUstep headers
bracketed in #ifndef STRICT_OPENSTEP
If a class or method is in OpenStep but not in MacOS-X or GNUstep
- it's a low priority TODO. It should be added to the GNUstep
headers bracketed in #ifndef STRICT_MACOS_X
There are a couple of people working on this already, so it's a good idea to get in touch with Adam or Richard to coordinate efforts.
You can write testcases - where the libraries fail tests, you could either fix the problem, or add it to the task list.
To write testcases, you need to use anonymous CVS to install the latest gstep-core snapshot you can find. Then checkout the 'tests' module from CVS. In the 'tests' directory, you will find a regression testing framework for gstep-base. In order to use this you will also need a recent (v 1.3.2 or later) copy of Guile (you can get this from a GNU ftp site) and will need to hacke checked out, built, and installed the 'guile' package from the GNUstep CVS repository.
At present, there is no such framework for the gui library - If you are interested in working on one, contact richard@brainstorm.co.uk
You can either look at the links on the GNUstep website for applications that have been started, and email their owners to volunteer to help, or you can start your own project.
If you are starting your own project, you need to - 1. Get the latest snapshot of GNUstep and build it to use the 'xgps' or 'xdps' backend library. 2. Look at the example applications (particularly Ink.app) in the gstep-examples package directory as a basis for your work. 3. Be prepared to a) ask for help on the gnustep-discuss mailing list b) fix bugs and implement missing functionality in the gui and xgps libraries.
Talk to Adam Fedor fedor@gnu.org, the maintainer.
The GNUstep website is kept as a CVS module, but the largest portions of it (the FAQ, the TODO list, and the Documentation) are actually generated from files in the individual GNUstep packages.
If you want to update the FAQ or TODO list or documentation - grab the latest snapshot of the GNUstep core you can find, update it from the CVS repository, and work with the contents of the appropriate documentation directory.
If you want to work on other parts of the website - capture the pages you want to edit in your web browser (at http://www.gnustep.org). If you can't do that, you can grab a copy of the website via anonymous CVS -
$ CVSROOT=:pserver:anoncvs:@cvs.net-community.com:/gnustep-www $ export CVSROOT $ cvs login (password anoncvs) $ checkout -z3 www
The main task with the website is to figure out which bits are out-of-date (or wrong) and update/mark-as-outdated as required.
Current status -
The 'developers section' of the FAQ is being worked on by stevensl@mindspring.net, and we are looking at rewriting the more general parts of the FAQ.
Read the file `GNUstep-HOWTO', which comes with the GNUstep distribution, and also is available separately on the GNUstep ftp sites. A PDF version also exists on the web site called `GnustepInstall.pdf'.
Check http://www.gnustep.org/resources/sources.html for links to sites with RPMS, and perhaps in the future, Debian packages. In some cases. You can check the debian site for preconfigured GNUstep packages.
This occurs on some GNU/Linux systems. You'll need to change the optimization level, usually like this:
make OPTFLAG=-O
The Objective C Runtime Library provides C functions and data structures required to execute an Objective C program.
The GNU Objective C Runtime Library offers everything NeXT's runtime does, including Categories, Protocols, `+poseAs:', thread-safety, class initialization on demand, delayed loading of classes, and initialization of static instances (such as @""-style string objects).
It also has several improvements over NeXT's implementation:
No. Unlike NeXT's `cc', GNU GCC does not support source files containing both Objective C and C++. People at Cygnus have mentioned that they would be willing to do the work--if they were paid for it, of course. Several people are interested in seeing this happen. Send email to `discuss-gnustep@gnu.org' if you are interesting in pushing this issue, so that the efforts of all those people interested can be coordinated.
Also, unlike NeXT's `cc', GNU GCC does not support the `extern "Objective-C"' construct.
The FAQ associated with the newsgroup `comp.lang.objective-c' contains more information about GNU Objective C.
The GNUstep Base Library is a library of general-purpose, non-graphical Objective C objects. For example, it includes classes for strings, object collections, byte streams, typed coders, invocations, notifications, notification dispatchers, moments in time, network ports, remote object messaging support (distributed objects), event loops, and random number generators.
It provides functionality that aims to implement the non-graphical portion of the OpenStep standard (the Foundation library).
It is about 98 percent of the way to having all the OpenStep classes (and the later OPENSTEP/Rhaspody classes) fully implemented. Normal work can already be done using the library since the missing 2 percent are the least-often-used features or are simply not up to date with the latest MacOS-X spec. Over 60,000 lines of code have already been written.
GNU Distributed Objects has many of the features of other distributed objects implementations, but, since it is free software, it can be ported to platforms for which other distributed objects implementations are not available.
[NOTE: The GNU distributed object facilities have the same ease-of-use as NeXT's; be warned, however, that they are not compatible with each other. They have different class heirarchies, different instance variables, different method names, different implementation strategies and different network message formats. You cannot communicate with a NeXT NSConnection using a GNU Connection.
Here are some differences between GNU distributed objects and NeXT's distributed objects: NeXT NSDistantObject asks it's remote target for the method encoding types and caches the results; GNU NSDistantObject gets the types directly from the local GNU "typed selector" mechanism if the information is known locally and only queries the remote target or caching encoding types when using a method that is not known to the local process. The NSProxy for the remote root object always has name 0 and, once set, you cannot change the root object of a NSConnection; the GNU Proxy for the remote root object has a target address value just like all other Proxy's, and you can change the root object as many times as you like. ].
The GNUstep GUI Library is a library of objects useful for writing graphical applications. For example, it includes classes for drawing and manipulating graphics objects on the screen: windows, menus, buttons, sliders, text fields, and events. There are also many peripheral classes that offer operating-system-independent interfaces to images, cursors, colors, fonts, pasteboards, printing. There are also workspace support classes such as data links, open/save panels, context-dependent help, spell checking.
It provides functionality that aims to implement the `AppKit' portion of the OpenStep standard. However the implementation has been written to take advantage of GNUstep enhancements wherever possible.
The GNUstep GUI Library is divided into a front- and back-end. The front-end contains the majority of implementation, but leaves out the low-level drawing and event code. A back-end can override whatever methods necessary in order to implement low-level drawing event receiving. Different back-ends will make GNUstep available on various platforms. The default GNU back-end will run on top of X Windows and the DisplayGhostScript Server. Other back-ends could allow GNUstep to run on OpenGL, OS/2, and WIN32 graphics/event platforms. Much work will be saved by this clean separation between front- and back-end, because it allows different platforms to share the large amount of front-end code.
Many of the classes are well implemented, if not thouroughly tested. See the GNUstep web sites and read status information contained in the distribution for the most up-to-date information.
It works, but is slow and buggy. A lot of work could be done.
It is a free implementation of a Display PostScript server based on the GNU Ghostscript program developed by Aladdin Enterprises and now owned by artofcode LLC.
GNU contracted with Aladdin Enterprises to add some key features to GNU Ghostscript so it could be used as a DPS server. This work has mostly been done, although Aladdin did not completely finish the work that they were contracted for. (Because the work took longer than specified and was not completed, Aladdin agreed to waive approximately $10,000 in promised fees for the work that was actually done and delivered.) DGS works fairly well with a single context. Alpha channel and compositing currently doesn't work, but should before the end of 2000 (It's already been fixed in GNU Ghostscript 6.0, just not released).
Display Ghostscript runs on top of X Windows.
All trademarks mentioned on in this FAQ belong to their owners.
Go to the first, previous, next, last section, table of contents.