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Mail Archives: djgpp/2001/06/25/09:10:10

Date: Mon, 25 Jun 2001 16:10:13 +0300 (IDT)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
X-Sender: eliz AT is
To: djgpp AT delorie DOT com
Subject: Re: Strange behavior of compiler.
In-Reply-To: <3b3726ec.239008545@news.primus.ca>
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On Mon, 25 Jun 2001, Graaagh the Mighty wrote:

> On Sun, 24 Jun 2001 10:35:20 +0300 (IDT), Eli Zaretskii
> <eliz AT is DOT elta DOT co DOT il> sat on a tribble, which squeaked:
> 
> >Why do you insist speculating instead of stepping with a debugger into
> >the code
> 
> In this case, I'd be stepping for hours with the debuggers that
> actually seem to work at all.

Why is that?  Is it because the crashes happen after a lot of 
processing?  Does the crash happen predictably given some specific usage 
scenario?

> >It doesn't matter; -gstabs+ is better even without optimizations, when
> >you have tricky bugs like this one.
> 
> ISTR discussing this in connection with g++ a few months back, and the
> conclusion was that stabs debugging info was theoretically better but
> not available/broken/something else for some reason. Has this changed?

stabs debugging is better because the compiler generates much more 
detailed info, including more detailed line number information and other 
important data.

> If it has, why is it not the default format with -g now?

Because simify doesn't support stabs, for starters.  And because support 
for a better debug unfo format, called dwarf2, is in the works.

> With the other misbehaving program, FSDB
> wouldn't so much as run, AFAICT -- it died at startup with a segfault
> without ever reaching its UI to let me single step anything

That could be because you have DJGPP v2.02.  I think FSDB shipped with 
that version indeed crashed at startup.

> and RHGDB
> just quietly exited without any error message or normal output (IMO
> both of these indicate bugs in the respective programs -- anything
> that segfaults is buggy regardless of if it only happens with
> "pathological" user inputs, and anything that silently fails
> likewise).

Is this the latest RHGDB?  I'd suggest to get the latest versions of all 
the debuggers, including GDB 5.0.  The debug support in DJGPP v2.03 is 
_much_ better, including support for signals, exceptions, FP code 
debugging, etc.

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