@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 useful 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?, Which Foundation Library can I use?, 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 super-set 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 Which Foundation Library can I use?, How can I get GNUstep?, What is GNUstep's position towards KDE and the GNOME project?, 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 can I get GNUstep?, How do you run GNUstep?, Which Foundation Library can I use?, GNUstep General Information
Read the file @file{GNUstep-HOWTO}, which comes with the GNUstep
distribution (gnustep-make), 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 Installing
@subsection Are there any precompiled packages available?
Check @url{http://www.gnustep.org/resources/sources.html} for links to
RPMS. Debian packages are also available. You can check the debian
site(s) 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 Installing
@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. They have been
@node Can I run NeXT OPENSTEP or MacOSX programs on GNUstep?, Is GNUstep following Changes to OpenStep and MacOSX?, Compatibility and Layout, Compatibility and Layout
@subsection Can I run NeXT OPENSTEP or MacOSX 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 GNUstep following Changes to OpenStep and MacOSX?, Do we have to have the NeXTstep look and feel?, Can I run NeXT OPENSTEP or MacOSX programs on GNUstep?, Compatibility and Layout
@subsection Is GNUstep following Changes to OpenStep and MacOSX?
Yes, gnustep-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 Cocao.
@node Do we have to have the NeXTstep look and feel?, What's up with the directory structure?, Is GNUstep following Changes to OpenStep and MacOSX?, Compatibility and Layout
@subsection Do we have to have the NeXTstep look and feel?
GNUstep is aiming for something like the NeXTstep-3.3 look and feel.
Although we don't want to force anyone into this, a lot of the power and
ease of use comes from this feel. The look of GNUstep is something
different - buttons and other widgets can look different but still act
the same way. We hope to implement themes which will allow
this. Actually we're hoping someone will volunteer to do it.
@node What's up with the directory structure?, Why not use Frameworks?, Do we have to have the NeXTstep look and feel?, Compatibility and Layout
@subsection What's up with the directory structure?
First of all, GNUstep uses a slightly different directory structure than
NeXT or MacOSX. Part of this is historical, part is because we can't do
things the same way (see @pxref{Why not use Frameworks?}).
GNUstep also stores libraries and binaries in subdirectories based on
the operating system and cpu. This is so you can compile and store
binaries for different systems in the same directory structure. MacOSX
uses Fat binaries to accomplish this (another reason we do it
differently). If you want, you can get rid of this using the
@samp{--enable-flattened} option to the gnustep-make package.
@node Why not use Frameworks?, , What's up with the directory structure?, Compatibility and Layout
@subsection Why not use Frameworks?
Frameworks are much more difficult to port and to use, and are very
unnatural on a unix system - extremely unnatural on Windows. In a
framework, the shared dynamic library is inside a framework wrapper
directory. Because of this, the dynamic linker can't find it.
We have frameworks, so how do we work around that? Well, we build dynamic
links from a directory inside the dynamic linker path into the framework,
which work, but then you can't move the framework anywhere else on
the system, otherwise you break the link, and nothing will find the
framework any longer!
On systems without dynamic links, like Windows, we can't even do this!
We have to copy the library from the framework into the dynamic linker
path, but that is simply a shared library then! Absolutely @emph{no}
difference. You put the dynamic library in a system directory in the
dynamic linker path, and associate with that library a resource directory.
I think OpenStep for Windows did that, and still called them frameworks.
Oh well we can do the same then, and call our libraries frameworks.
In a shared library, the shared dynamic library is in a directory which is
in the path to the dynamic linker. the dynamic linker can find it very
easily. this is how all shared and static libraries work on Unix systems,
on Windows systems and possibly on most system at all.
Moreover, the OpenStep API requires us to provide some stuff for
frameworks, like creating and registering automatically a framework
object each time a framework is used (linked at runtime, or linked into
the app), and attaching to it the list of classes inside the framework -
which are not particularly trivial to implement - they depend on playing
with the linker and the object file format - and might produce troubles
when porting. And we never use these facilities.
For Apple MacOSX sure it's easier. They can modify
the system linker, compiler, the system dynamical linker. They
always know on which platform they are working (their own), etc. They can
modify the system to support frameworks natively. Easy that way.
But GNUstep is meant to run on many different platforms, platforms which
we don't control (Windows, Sun Solaris, Darwin, GNU/Linux, Unix
variants) and which have different linkers and do not support frameworks
natively. On some systems it's difficult to just load a bundle or
compile a shared library!
So building the core libraries as 'libraries' means that it's much
easier to port them, and it's much more difficult to break them.
Sure, frameworks have a bundle of resources associated with it - but we
can very easily associate a bundle of resource with a shared library, no
reason why not. We are doing it.
So please note that GNUstep libraries are meant to be much similar to
MacOS X frameworks. They are composed of a shared library and
associated with a bundle of resources. There is a difference in
terminology, in where the resources are installed, and possibly a slight
difference in the NSBundle API to get to the resource bundle (anyway,
it's a one line difference between MacOSX and GNUstep, so it looks like
very easy to #ifdef).
In other words, GNUstep libraries are meant to basically do the same as
frameworks do on MacOSX, but to be portable to strange platforms (such as
