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libFoundation Library README
============================
History
=======
This library is derived from an old library we designed, wrote and
used for developing a commercial application during 1995.
That time we needed a small library that had some general
containers and strong support for distributed objects. We needed
to write code that runs on different machines, not only on NeXT.
Also we needed to write programs that communicate via general Unix
IPC channels. So we designed a library that had support for
distributed objects on different channels of communication like
Internet or Unix domain stream sockets or socketpairs.
We also experimented some ideas, such as calling the exception
handlers as functions and returning from them, choosing the best
communication channel when a connection is established and some
other interesting ideas.
The design of the library
=========================
We have followed two important points in designing this
library. The first is runtime independence. The second is to write
the code without using extensions to the OpenStep spec, or if we
are using such extensions, we provide a separate library
containing them that allows porting of the code written for
libFoundation to another implementation of Foundation.
We wanted to give people a library that compiles and runs in the
both worlds of Objective-C: NeXT and GNU. This will allow one to
write programs that mix together the code that exists for NeXT and
the code that runs only on the GNU runtime. libFoundation compiles
with both runtimes using different compilers. If all the other
GNUstep work would be done to allow easy porting of programs, then
one can move easily from NeXT's OpenStep to GNUstep.
The library includes a header file that allows you to write the
programs portable across runtimes. If you write the programs using
only the GNU API without some GNU runtime dependent facilities
your programs will also run without modifications on both GNU and
NeXT runtime.
The actual extensions are the exception handling mechanism and the
garbage collector based on reference counting. The exception
handling mechanism offers a better approach to exception handling
than that found in the OpenStep specification by using a more
intuitive syntax. In addition the exception handler is invoked as
a function so you can see in debugger where the exception was
generated from.
The garbage collector works in conjunction with the reference
counting mechanism and releases you from thinking on how to solve
the cycles in your program, thus saving time and code to write and
maintain.
For all these extensions we provide a separate library that
compiles with other implementations of Foundation.
Starting with version 0.9.0 support for Boehm's garbage collector
has been added; see
http://reality.sgi.com/employees/boehm_mti/
for more information on this collector. The support in
libFoundation includes the possibility of registering an object
for the finalization of another object, which is very important
for the implementation of classes like NSNotificationCenter in
libFoundation and EOObjectUniquer in GDL. See the documentation
for more details about this facitity.
The current status
==================
Almost all of the classes from the original OpenStep specification
are implemented. We also implemented several classes found in the
NeXT's OPENSTEP implementation like NSFileManager, NSFileHandle,
NSTask and NSPipe. We estimate the library is completed in
proportion of 80% from the original OpenStep specification;
extensions are not counted.
Almost all of the classes are thoroughly tested using a special
testing framework we designed.
Future work
===========
Starting with 0.8.0 libFoundation was made thread-safe. More
testing should be done: we need to come up with some automated
tests for checking the thread-safety of the library.
At this time libFoundation does not provide an implementation of
Distributed Objects (DO) and Unicode strings.
A small implementation for DO was written by Helge Hess and it
will eventually become part of libFoundation. This implementation
will be further worked on to be based upon the Corba's IIOP, which
will allow libFoundation's Distributed Objects clients to
communicate directly with Corba clients written in other
languages, that run using a variety of Corba implementations.
Mircea wrote most of the Unicode implementation but we still need
to come up with some good algorithms for searching Unicode
strings.
Resources
=========
Snapshots/releases of libFoundation will usually become available in
the contrib directory of the GNUstep site (ftp.gnustep.org).
There is also a web page on
http://www.geocities.com/SiliconValley/Monitor/7464/libFoundation/index.html
Remote access to the sources through CVS
========================================
You can have read-only access to the most recent developments on
libFoundation using anonymous CVS. To be able to do this setup the
CVSROOT environment variable like this (a Bourne shell is assumed):
CVSROOT=:pserver:anoncvs@cvs.net-community.com:/libFoundation
export CVSROOT
Then do a 'cvs login'. You will be prompted to introduce a password,
enter anoncvs.
Then issue this command to get the sources:
cvs -z 3 checkout libFoundation
Once you have the sources checked out you can update them to the
recent changes by running inside of libFoundation source tree:
cvs -z 3 update
GNUstep makefile package (gstep-make)
=====================================
GNUstep includes a makefile package, called gstep-make, which is
supported by the libFoundation. The package is available at the
GNUstep site (ftp.gnustep.org).
Take a look at the libFoundation INSTALL file on how to compile
lF using gstep-make.
Ports
=====
This package was compiled and tested on these machines:
m68k-next-nextstep3
The package was compiled and tested successfully using the
2.6.3 and 2.7.2 versions of compiler and with both NeXT and
GNU runtimes. Returning of aggregates of all sizes works well
with both runtimes.
i386-next-nextstep3
The package was compiled and tested successfully using the
2.6.3 and 2.7.2 versions of compiler and with both NeXT and
GNU runtimes. Returning of aggregates of all sizes works well
with both runtimes.
i386-next-nextstep4
The package was compiled and tested successfully using the
2.7.2.1 version of compiler with GNU runtime. The port of GNU
compiler on this machine does not work with nested functions
so parts of exception handling facility don't work.
i386-pc-linux-gnu
The package was compiled on linux with ELF using the 2.7.2.1,
with GCC 2.8.1 and with EGCS 1.0.3. All the tests ran
successfully, except some NSInvocation tests that crash when
returning some structures.
i386-pc-cygwin32
The package was compiled using the Cygnus Win32 beta 17.1
binaries, with the libobjc.a built from the newer gcc sources
with the 960906 runtime patch applied.
i386-pc-mingw32
The port to mingw32 is currently in progress. See README.mingw32
for information. The package is cross-compiled using egcs 1.1.1.
i386-sun-solaris2.5.1
The package was compiled with the 2.7.2.1 compiler with the
970317 runtime patch applied.
sparc-sun-solaris2.5
The package was compiled with the 2.7.2.1 compiler with the
960906 runtime patch applied.
See README.sparc for more information.
sparc-sun-solaris2.6
The package was compiled with a modified egcs 1.1.1 compiler.
See README.sparc for more information.
alpha-unknown-linux-gnu
The package was compiled using a pre-release of GCC version
2.8. Still needs some work to finish the NSInvocation and
NSMethodSignature machine dependent macros.
powerpc-ibm-aix4.1.5.0
The package was compiled using the EGCS 1.0.3a compiler with a
patch applied to it; the patch can be found in the
libFoundation's distribution. NSInvocation and
NSMethodSignature have been ported.
Some preliminary work has been done on HPUX 9. This platform is
obsolete and we'll try to port the library to 10.20 and 11.0.
Happy hacking,
Ovidiu Predescu <ovidiup@altavista.net>
Mircea Oancea <mircea@pathcom.com>
Helge Hess <helge.hess@skyrix.com>
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