Re: debugging dynamic functions

[Douglas Eck]

I think this is useful. 
I'll add this to the still-growing octave dynamic FAQ.

-Doug

Braddock Gaskill wrote:
> 
> Okay, I finally think I figured out the right way to debug dynamic
> functions.  Maybe this should go in the FAQ or something, because it
> makes Octave oh-so-useful for debugging C algorithms.
> 
> -Compile your .oct functions with debugging symbols (-g)
> 
> -Launch and run octave under gdb (ie, `gdb octave`)
> 
> -Call your dynamically linked function once so that the .oct file and
> any dependent shared libraries get loaded (is there a way to force loading?).
> 
> -ctrl-C to send a trapped break signal to Octave and drop you to the gdb 
> prompt
> 
> -type `info shar` at the gdb prompt to see all the dynamically linked
> libraries, including your .oct file.  Take note of the "Syms Read"
> column..your .oct file should say "No", meaning no symbols have been
> loaded (even if they are in the binary)
> 
> -type 'share myoctavefunc.oct' to load the debugging symbols, with
> proper address translation, into gdb.  Type 'info shar' again to see
> that they've been loaded.
> 
> -Now add your breakpoints or whatever like your normally would.  Life should 
> be good.
> 
> This all works for me under Linux Mandrake 7.2 with GDB 5.0.  Note,
> btw, that I learned the hard way that the add-symbol-file command in
> gdb 5 is known to be broken, so you have to use 'share' and you can't
> do it by hand unles you move to a development version of gdb.
> 
> BTW, I'm now using a shared lib in my .oct files very nicely with the
> mkoctfile -l command as suggested by jwe...thanks!
> 
>         Hope this saves people my pain!
>         -Braddock
> 
> --
> Invention is 99% perspiration; is it fair to patent the 1% of inspiration? -BG
> 
>   
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>    Part 1.2Type: application/pgp-signature

-- 
Dr. Douglas Eck, http://www.idsia.ch/~doug
Istituto Dalle Molle di Studi sull'Intelligenza Artificiale (IDSIA)
Neural Networks, Rhythm Perception and Production, Dynamical Systems



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