tools-make/Documentation/faq.texi

\input texinfo   @c -*-texinfo-*-
@c A FAQ for GNUstep

@node Top, GNUstep General Information, (dir), (dir)
@chapter GNUstep Frequently Asked Questions with Answers

Last updated @today{}
Please send corrections to @email{gnustep-maintainer@@gnu.org}.

@menu
* GNUstep General Information::  
* Compatibility with OPENSTEP/Cocoa/MacOSX::  
* Compiling and Developing::    
* GNU Objective C Compiler and Objective C Runtime Library::  
* GNUstep Base Library::        
* GNUstep GUI Library::         
* GNUstep DisplayGhostScript Server::  
@end menu

@node GNUstep General Information, Compatibility with OPENSTEP/Cocoa/MacOSX, Top, Top
@section GNUstep General Information

@menu
* What is GNUstep?::            
* What is the OpenStep standard?::  
* What platforms does GNUstep run on?::  
* Does GNUstep run on Windows?::  
* What is GNUstep's position towards KDE and the GNOME project?::  
* Is the Objective C API for GTK related?::  
* How about implementing parts of the Application Kit with GTK?::  
* Which compiler can I use? Where can I get it?::  
* Which Foundation Library can I use?::  
* How do you use the gnustep-make package?::  
* How can I get GNUstep?::      
* How do you run GNUstep?::     
* Is there a web site?::        
* When is GNUstep intended to be available?::  
* What is usable?::             
@end menu

@node What is GNUstep?, What is the OpenStep standard?, GNUstep General Information, GNUstep General Information
@subsection What is GNUstep?

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:

@itemize @bullet

@item GNU Objective C Compiler and Objective C Runtime Library -
Although not actually a component of GNUstep, GCC and the GNU
Objective C Runtime Library are integral to GNUstep, since they are used
to make every GNU Objective C program.

@item GNUstep Base Library - Code for non-graphical objects, such as
strings, collections, archiving support and distributed objects
messaging.  (Including functionality similar to OpenStep's
@samp{FoundationKit}.)

@item GNUstep GUI Library - Code for graphical objects used in making a
Graphical User Interface (GUI).  This includes buttons, sliders, text
fields, windows, menus, etc.  (Including functionality similar to
OpenStep's @samp{AppKit}.)

@item GNUstep DisplayGhostscript Server - A server that draws PostScript
graphics to the screen, and receives events from the keyboard and
mouse.  It is based on GNU GhostScript. There is also an DPS extension to
Xfree*6 that is usable.

@item Various Tools and applications, including GORM, The GNUstep
interface builder for graphically assembling application interfaces, and
ProjectCenter, a project manager.

@end itemize

@node What is the OpenStep standard?, What platforms does GNUstep run on?, What is GNUstep?, GNUstep General Information
@subsection What is the OpenStep standard?

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 @samp{FoundationKit}, a library of
non-graphical objects; the @samp{AppKit}, a library of objects usful in
creating graphical applications; and @samp{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
@url{http://www.gnustep.org} or it's mirror sites.

@node What platforms does GNUstep run on?, Does GNUstep run on Windows?, What is the OpenStep standard?, GNUstep General Information
@subsection What platforms does GNUstep run on?

See the list of supported platforms at
@url{http://www.gnustep.org/information/machines_toc.html} for
information on what machines GNUstep builds on and what the status of
the ports is. Probably a few days porting to any other Unix system where
current gcc/egcs compilers and gdb debugger work.

@node Does GNUstep run on Windows?, What is GNUstep's position towards KDE and the GNOME project?, What platforms does GNUstep run on?, GNUstep General Information
@subsection  Does GNUstep run on Windows?

  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.


@node What is GNUstep's position towards KDE and the GNOME project?, Is the Objective C API for GTK related?, Does GNUstep run on Windows?, GNUstep General Information
@subsection  What is GNUstep's position towards KDE and the GNOME project?

  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.


@node Is the Objective C API for GTK related?, How about implementing parts of the Application Kit with GTK?, What is GNUstep's position towards KDE and the GNOME project?, GNUstep General Information
@subsection  Is the Objective C API for GTK related?

  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.

@node How about implementing parts of the Application Kit with GTK?, Which compiler can I use? Where can I get it?, Is the Objective C API for GTK related?, GNUstep General Information
@subsection  How about implementing parts of the Application Kit with GTK?

  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.

@node Which compiler can I use? Where can I get it?, Which Foundation Library can I use?, How about implementing parts of the Application Kit with GTK?, GNUstep General Information
@subsection  Which compiler can I use? Where can I get it?

  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/

@node Which Foundation Library can I use?, How do you use the gnustep-make package?, Which compiler can I use? Where can I get it?, GNUstep General Information
@subsection  Which Foundation Library can I use?

  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.


@node How do you use the gnustep-make package?, How can I get GNUstep?, Which Foundation Library can I use?, GNUstep General Information
@subsection  How do you use the gnustep-make package?

  Good question.  Read the tutorials at the GNUstep web site. Also, use the
makefiles in the libraries, tool directories, and test applications as
examples.

@node How can I get GNUstep?, How do you run GNUstep?, How do you use the gnustep-make package?, GNUstep General Information
@subsection  How can I get GNUstep?

  Get the HOWTO from 
@url{http://www.gnustep.org/resources/documentation/GNUstep-HOWTO}
Get the latest release from @url{ftp://ftp.gnustep.org}. If you're
really adventurous, get the latest snapshot by anonymous ftp from
@url{ftp://ftp.gnustep.org:/pub/daily-snapshots}

Use anonymous CVS to keep up to date - instructions are in the
HOWTO.

@node How do you run GNUstep?, Is there a web site?, How can I get GNUstep?, GNUstep General Information
@subsection  How do you run GNUstep?

 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 -

@example
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.
@end example

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.

@node Is there a web site?, When is GNUstep intended to be available?, How do you run GNUstep?, GNUstep General Information
@subsection  Is there a web site?

See @url{http://www.gnustep.org/}.

@node When is GNUstep intended to be available?, What is usable?, Is there a web site?, GNUstep General Information
@subsection  When is GNUstep intended to be available?

It's usable now. 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.

@node What is usable?,  , When is GNUstep intended to be available?, GNUstep General Information
@subsection  What is usable?

@itemize @bullet
@item gstep-make does pretty much what the makefiles in NeXTstep do.
@item gstep-base (Foundation) stuff should work fine for almost all projects.
@item gstep-db is only EOF-1.0 compatible but should work ok.
@item gstep-gui (AppKit) has a lot working but there is still stuff missing.
@item DGS (Display Ghostscript) is usable but slow.
@end itemize

@c ****************************************************************
@c Compiling
@node Compatibility with OPENSTEP/Cocoa/MacOSX, Compiling and Developing, GNUstep General Information, Top
@section Compatibility with OPENSTEP/Cocoa/MacOSX

@menu
* Can I run NeXT OPENSTEP or Apple Rhapsody programs on GNUstep?::  
* Is it easy to port OPENSTEP and Rhapsody programs to GNUstep?::  
* Can I transfer archived data from GNUstep to Cocoa?::  
* Does distributed objects work between GNUstep and Cocoa?::  
* Is there an Interface Builder for GNUstep?::  
* Can I use my original NIB files?::  
* Will code without NIB files work?::  
* Is GNUstep following Apple's Changes to OpenStep?::  
* Do we have to have the NeXTstep look and feel?::  
* Can one use the hybrid "Objective-C++"::  
* Is there a plan to support Java/YellowBox Bindings?::  
* What if I compile GNUstep under OPENSTEP/MacOS X Server?::  
@end menu

@node Can I run NeXT OPENSTEP or Apple Rhapsody programs on GNUstep?, Is it easy to port OPENSTEP and Rhapsody programs to GNUstep?, Compatibility with OPENSTEP/Cocoa/MacOSX, Compatibility with OPENSTEP/Cocoa/MacOSX
@subsection Can I run NeXT OPENSTEP or Apple Rhapsody programs on GNUstep?

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.

@node Is it easy to port OPENSTEP and Rhapsody programs to GNUstep?, Can I transfer archived data from GNUstep to Cocoa?, Can I run NeXT OPENSTEP or Apple Rhapsody programs on GNUstep?, Compatibility with OPENSTEP/Cocoa/MacOSX
@subsection Is it easy to port OPENSTEP and Rhapsody programs to GNUstep?

It is probably easy for simple programs. There are some portability
tools
to make this easier (@url{http://www.gnustep.org/resources/source_port.html}),
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 @url{ftp://ftp.gnustep.org/pub/gnustep/dev-apps}).

@node Can I transfer archived data from GNUstep to Cocoa?, Does distributed objects work between GNUstep and Cocoa?, Is it easy to port OPENSTEP and Rhapsody programs to GNUstep?, Compatibility with OPENSTEP/Cocoa/MacOSX
@subsection Can I transfer archived data from GNUstep to Cocoa?

Apple's archiving format is proprietary and not documented, so this
poses a problem for anyone wanting to implement compatibility with it.
However, even if we reverse engineered the format, there are enough
differences between the class and ivar layouts to make this sort of
compatibility difficult. Not to mention the fact that we would
constantly have to keep up with the changes Apple made. Also Apple's
archiving format, as far as we know, would not be compatible between
different machines because of endiness issues, although GNUstep doesn't
have this problem.

Your best bet is to implement your own archiving format that would work
both with GNUstep and Cocoa. Fortuneatly, you don't have to start from
scratch, since this has been essentially done for you in the nib2gmodel
tool, which has an archiver that works both on GNUstep and Cocoa. It
might be nice to split this off into a separate project to make it
easier for other people to do the same thing.

@node Does distributed objects work between GNUstep and Cocoa?, Is there an Interface Builder for GNUstep?, Can I transfer archived data from GNUstep to Cocoa?, Compatibility with OPENSTEP/Cocoa/MacOSX
@subsection Does distributed objects work between GNUstep and Cocoa?

See the answer to the previous question (on archive compatibility) for
why this won't work either.

@node Is there an Interface Builder for GNUstep?, Can I use my original NIB files?, Does distributed objects work between GNUstep and Cocoa?, Compatibility with OPENSTEP/Cocoa/MacOSX
@subsection Is there an Interface Builder for GNUstep?

There is an Interface Builder for GNUstep called Gorm, but it is
in alpha release, so it may not work perfectly. You can download it from
the ftp site or via http.
The Project Manager ProjectCenter is also available.

@node Can I use my original NIB files?, Will code without NIB files work?, Is there an Interface Builder for GNUstep?, Compatibility with OPENSTEP/Cocoa/MacOSX
@subsection  Can I use my original NIB files?

 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 called nib2gmodel that can be compiled under OPENSTEP to convert
OPENSTEP nib files to GNUstep gmodel files.

@node Will code without NIB files work?, Is GNUstep following Apple's Changes to OpenStep?, Can I use my original NIB files?, Compatibility with OPENSTEP/Cocoa/MacOSX
@subsection  Will code without NIB files work?

 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.

@node Is GNUstep following Apple's Changes to OpenStep?, Do we have to have the NeXTstep look and feel?, Will code without NIB files work?, Compatibility with OPENSTEP/Cocoa/MacOSX
@subsection  Is GNUstep following Apple's Changes to OpenStep?

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.

@node Do we have to have the NeXTstep look and feel?, Can one use the hybrid "Objective-C++", Is GNUstep following Apple's Changes to OpenStep?, Compatibility with OPENSTEP/Cocoa/MacOSX
@subsection  Do we have to have the NeXTstep look and feel?

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.

@node Can one use the hybrid "Objective-C++", Is there a plan to support Java/YellowBox Bindings?, Do we have to have the NeXTstep look and feel?, Compatibility with OPENSTEP/Cocoa/MacOSX
@subsection  Can one use the hybrid "Objective-C++"
that one could on the NeXT?

 No - at present the GNU compiler (gcc) does not support
"Objective-C++" There are no specific plans to make it do so, but
any volunteers to do it would be welcome.

@node Is there a plan to support Java/YellowBox Bindings?, What if I compile GNUstep under OPENSTEP/MacOS X Server?, Can one use the hybrid "Objective-C++", Compatibility with OPENSTEP/Cocoa/MacOSX
@subsection  Is there a plan to support the Java/YellowBox Bindings?

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.

@node What if I compile GNUstep under OPENSTEP/MacOS X Server?,  , Is there a plan to support Java/YellowBox Bindings?, Compatibility with OPENSTEP/Cocoa/MacOSX
@subsection  What if I compile GNUstep under OPENSTEP/MacOS X Server?

 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, the GNUstep base library is still being ported to Darwin.

@c ****************************************************************
@c Compiling
@node Compiling and Developing, GNU Objective C Compiler and Objective C Runtime Library, Compatibility with OPENSTEP/Cocoa/MacOSX, Top
@section Compiling and Developing

@menu
* How can I help with GNUstep?::  
* How do I start writing code?::  
* How do I start writing documentation?::  
* How do I update the task list?::  
* How do I start writing tests?::  
* How do I start writing applications?::  
* How can I help with the GNUstep website?::  
* How do I compile GNUstep on my machine? ::  
* Are there any precompiled packages available?::  
* What are these type and size warnings?::  
@end menu

@node How can I help with GNUstep?, How do I start writing code?, Compiling and Developing, Compiling and Developing
@subsection  How can I help with GNUstep?

@enumerate
@item Write/debug library code 
@item Write documentation 
@item Update the TODO list and library headers 
@item Write applications
@end enumerate

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.


@node How do I start writing code?, How do I start writing documentation?, How can I help with GNUstep?, Compiling and Developing
@subsection  How do I start writing code?

 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 GNUstep
website.

Once you have coded something, you could always write a testcase
and documentation for it :-)

@node How do I start writing documentation?, How do I update the task list?, How do I start writing code?, Compiling and Developing
@subsection  How do I start writing documentation?

All class documentation is written directly in the source code itself
and translated using the autogsdoc program. See the source code and
documentation for autogsdoc for information on documenting the classes.

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.

@node How do I update the task list?, How do I start writing tests?, How do I start writing documentation?, Compiling and Developing
@subsection  How do I update the task list?

 The task list (@url{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.

Send any changes or additions to @email{bug-gnustep@@gnu.org}.

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 @code{#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 @code{#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.

@node How do I start writing tests?, How do I start writing applications?, How do I update the task list?, Compiling and Developing
@subsection  How do I start writing tests?

 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 GNUstep snapshots you can find. Then checkout the 'tests'
module from CVS.  In the 'tests' directory, you will find a
regression testing framework.
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.

@node How do I start writing applications?, How can I help with the GNUstep website?, How do I start writing tests?, Compiling and Developing
@subsection  How do I start writing applications?

 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.

@node How can I help with the GNUstep website?, How do I compile GNUstep on my machine? , How do I start writing applications?, Compiling and Developing
@subsection  How can I help with the GNUstep website?

 Talk to Adam Fedor @email{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, you can grab a copy
of the website via anonymous CVS. See
@url{http://savannah.gnu.org/cvs/?group_id=99} for instructions on how
to do that.

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.

@node How do I compile GNUstep on my machine? , Are there any precompiled packages available?, How can I help with the GNUstep website?, Compiling and Developing
@subsection How do I compile GNUstep on my machine?

Read the file @file{GNUstep-HOWTO}, which comes with the GNUstep
distribution, and also is available separately on the GNUstep web
site. 

@node Are there any precompiled packages available?, What are these type and size warnings?, How do I compile GNUstep on my machine? , Compiling and Developing
@subsection Are there any precompiled packages available?

Check @url{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. Also check the BSD sites for GNUstep ports.

@node What are these type and size warnings?,  , Are there any precompiled packages available?, Compiling and Developing
@subsection What are these type and size warnings?

These warnings:
@example
/usr/bin/ld: warning: type and size of dynamic symbol
`__objc_class_name_NSConstantString' are not defined
@end example

are a common occurence and are due to a mismatch between gcc and
ld. They don't do any harm so they can be safely ignored. Apparently no
one has bothered to fix them yet.

@c -------------------------------------------------------------------

@node GNU Objective C Compiler and Objective C Runtime Library, GNUstep Base Library, Compiling and Developing, Top
@section GNU Objective C Compiler and Objective C Runtime Library

@menu
* What is the Objective C Runtime Library?::  
* Does it allow a mixture of Objective C and C++::  
* Where can I find more information?::  
@end menu

@node What is the Objective C Runtime Library?, Does it allow a mixture of Objective C and C++, GNU Objective C Compiler and Objective C Runtime Library, GNU Objective C Compiler and Objective C Runtime Library
@subsection What is the Objective C Runtime Library?

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, @samp{+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:

@itemize @bullet

@item NeXT's runtime requires an extra function call (objc_msgSend) for
each message that is sent; (the function looks up the receiving
instance's implementation of the method).  GNU's implementation is
faster because it does not use an extra function call.  Instead, it
inlines a short piece of code that makes two pointer hops into a method
dispatch table; because the code is inlined, it does not incur the
overhead of a function call.

@item When running in thread-safe mode, NeXT's runtime must aquire a
global mutual exclusion lock every time a message is sent; this is
extremely slow.  GNU's runtime, amazingly, sends messages just as fast
in thread-safe mode as it does in single-thread mode---the code path
does not contain even a single extra instruction!  The GNU runtime only
needs locks when certainly structures are written, not read; the
structures are written relatively infrequently: only at class
initialization and when @samp{+poseAs:} is called.

@item GNU's runtime provides ``selector-types'' along with each
selector; NeXT's does not.  A selector-type is a string that describes
the C variable types for the method's return and argument values.  Among
other uses, selector-types is extrememly helpful for fast distributed
objects implementations, (see GNUstep Base Library Section, below).

@item Many of the GNU functions have different names than their
corresponding NeXT functions; the GNU names conform to the GNU coding
standards.

@item NeXT's compiler, @samp{cc}, is based on an old version of
@samp{gcc}.  GNU's compiler is, of course, the latest version of
@samp{gcc}, and therefore contains all the latest enhancements.

@end itemize

@node Does it allow a mixture of Objective C and C++, Where can I find more information?, What is the Objective C Runtime Library?, GNU Objective C Compiler and Objective C Runtime Library
@subsection Does it allow a mixture of Objective C and C++?

No.  Unlike NeXT's @samp{cc}, GNU GCC does not support source files
containing both Objective C and C++.  Apple seems to be willing to
merge their code back into the main GCC project, but this may take some
convincing of the GCC maintainers due to the large number of changes
necessary. Send
email to @samp{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 @samp{cc}, GNU GCC does not support the @samp{extern
"Objective-C"} construct.

@node Where can I find more information?,  , Does it allow a mixture of Objective C and C++, GNU Objective C Compiler and Objective C Runtime Library
@subsection Where can I find more information?

The FAQ associated with the newsgroup @samp{comp.lang.objective-c}
contains more information about GNU Objective C.

@c ------------- GNU Compiler and Objective C Runtime Library -------

@node GNUstep Base Library, GNUstep GUI Library, GNU Objective C Compiler and Objective C Runtime Library, Top
@section GNUstep Base Library

@menu
* What is the GNUstep Base Library?::  
* What is base's current state of development?::  
* What are the features of GNU Distributed Objects?::  
@end menu

@node What is the GNUstep Base Library?, What is base's current state of development?, GNUstep Base Library, GNUstep Base Library
@subsection What is the GNUstep Base Library?

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).  

@node What is base's current state of development?, What are the features of GNU Distributed Objects?, What is the GNUstep Base Library?, GNUstep Base Library
@subsection What is its current state of development?

GNUstep base is currently stable and implements probably 99% of the
functionality of the OpenStep classes and most all of the new Carbon
classes.
Normal work can already be done using the library since the
missing 1 percent are the least-often-used features or are simply not
up to date with the latest Carbon spec.

@node What are the features of GNU Distributed Objects?,  , What is base's current state of development?, GNUstep Base Library
@subsection What are the features of GNU Distributed Objects?

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. ].

@c --------------------------GNUstep Base Library----------------------

@node GNUstep GUI Library, GNUstep DisplayGhostScript Server, GNUstep Base Library, Top
@section GNUstep GUI Library

@menu
* What is the GUI Library?::    
* Explain the organization of the front- and back-ends::  
* What is the current state of development of the front-end?::  
* What is the current state of development of the X/DPS back-end?::  
@end menu

@node What is the GUI Library?, Explain the organization of the front- and back-ends, GNUstep GUI Library, GNUstep GUI Library
@subsection What is the GUI Library?

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 @samp{AppKit}
portion of the OpenStep standard.  However the implementation has
been written to take advantage of GNUstep enhancements wherever possible.


@node Explain the organization of the front- and back-ends, What is the current state of development of the front-end?, What is the GUI Library?, GNUstep GUI Library
@subsection Explain the organization of the front- and back-ends

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.

@node What is the current state of development of the front-end?, What is the current state of development of the X/DPS back-end?, Explain the organization of the front- and back-ends, GNUstep GUI Library
@subsection What is the current state of development of the front-end?

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.

@node What is the current state of development of the X/DPS back-end?,  , What is the current state of development of the front-end?, GNUstep GUI Library
@subsection What is the current state of development of the X/DPS back-end?

It works, but is slow and buggy. A lot of work could be done.

@c ------------------------- GNUstep GUI Library -----------------------

@node GNUstep DisplayGhostScript Server,  , GNUstep GUI Library, Top
@section GNUstep DisplayGhostScript Server

@menu
* What is the Display Ghostscript Server?::  
* What is DGSs current state of development?::  
* What is the relationship between the Display Ghostscript Server and X Windows?::  
@end menu

@node What is the Display Ghostscript Server?, What is DGSs current state of development?, GNUstep DisplayGhostScript Server, GNUstep DisplayGhostScript Server
@subsection What is the Display Ghostscript Server?

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.

@node What is DGSs current state of development?, What is the relationship between the Display Ghostscript Server and X Windows?, What is the Display Ghostscript Server?, GNUstep DisplayGhostScript Server
@subsection What is its current state of development?

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.

@node What is the relationship between the Display Ghostscript Server and X Windows?,  , What is DGSs current state of development?, GNUstep DisplayGhostScript Server
@subsection What is the relationship between the Display Ghostscript Server and X Windows?

Display Ghostscript runs on top of X Windows.

@c ------------------ GNUstep DisplayGhostScript Server ---------------

@format
All trademarks mentioned on in this FAQ belong to their owners.
@end format

@bye
\bye