The Objective C aware GDB debugger available

[Benedikt Stefansson]

Swarmers,

As Ted informed us some while ago Michael Snyder at NeXT has patched the
GNU debugger (GDB) so that it is now Objective C aware. I failed
miserably at patching my own GDB sources and have been looking all over
for a patched source that is "fool proof" for someone of my level of
intelligence.

I'm happy to announce that I finally found the darn thing and compiled
it on my Linux box. Although I've only played with it for one day the
debugger now seems to work beautifully with Objective C. For example you
can now break on Objective C methods as in

    (gdb) break [Classname Selector: withArg:andArg]

or stop the program and call methods do see what is going on as in:

    (gdb) call [self someMethod: 12 withArg: 345]

and if you say:

    (gdb) break step

where step is a method found in more than one class, GDB will print out
all the different classes that have that method and ask you which one
you want to refer to.

I put the executable for i586-unknown-linux (ELF) on a couple of ftp
sites on both sides of the Atlantic. Those with a compliant Linux
distribution should be able to download the tar file, unzip and untar
it. Then you just need to move the gdb file to your /usr/bin directory
(or somewhere else on your path if that is what you want)..

Just in case Murphy is alive and well at your site it might be wise to
back up the old gdb version first under a different name, e.g.

                        mv gdb gdb.old

Moreover, if you can't get the executable to work, download the source
from the same directory and compile it. Basically all you need to do is
to type"

                        ./configure
                        make

and then proceed to move the gdb executable to /usr/bin.

I'm sure that if we ask Glen nicely he'll copy the files to the
Swarm/SFI ftp site. In the meantime the URLs for the tar'ed (and
gzip'ed) executable are,

(North America):

ftp://cce.sscnet.ucla.edu/pub/gdb-objc-4.16/gdb-objc-4.16.i586.linux.ELF.tar.gz

(Europe)

ftp://black.gelso.unitn.it/pub/gdb-objc-4.16/gdb-objc-4.16.i586.linux.ELF.tar.gz

In the same directory you'll also find the patched source and  a
newsgroup message from Michael Snyder (that is also included as a README
file in the tar archive with the executable).

The site where I got this stuff from is:

 ftp://ftp.nmr.embl-heidelberg.de/pub/next/OpenStep/GNUstep/Sources/

Remember, that the GNU licence allows distribution of executable code
but dictates that it should always be accompanied by the source code; I
guess by splitting up the executable and source into two tar files I am
not violating this principle.

Regards,
-Benedikt

----------------------------------------------------------------------------

Address:                               | May-June 1997:
-----------------------------------------------------------------------------

Center for Computable Economics        | Laboratorio di Economia
Sperimentale
Department of Economics                | Dipartimento di Economia
UCLA                                   | Universita degli Studi di
Trento
405 Hilgard Avenue, LA, CA 90095-1477  | Via Inama 1, Trento 38100,
Italy
Tel +1 310 825 1777 Fax +1 310 825 9528| Tel +39 461 882246 Fax +1 461
882222
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