Re: Re: gdb backtrace for g++ programs showing ?? symbol

[Naam Nahin]

Paul Pluzhnikov wrote:
> "naam nahin" <naam.yaad.nahin@gmail.com> writes
> > I am trying to debug a C++ program on Linux. g++ version is 4.1.3.
> > While debugging the program under gdb, I get a SIGABRT with the following 
> > backtrace:
> >
> > #4  0xb7ef0f65 in ?? () from /usr/lib/libstdc++.so.6
> >     
> > However, I don't know why I see "??" as the function symbol in
> > frame 4. Why can't gdb show me the function name for that
> > function?
> >     
>
> Probably because there is no 'reasonable' function for gdb to print:
> your libstdc++ was built without debug info, and is likely partially
> stripped of symbols. 
Thanks for the details. To get the debug version of libstdc++,
I installed the debug library and passed in -D_GLIBCXX_DEBUG as
a command line parameter. However, I still see (through ldd) that my
program depends upon the release version of libstdc++ and does not
show the full debug stack trace (like the one you have shown). How
do I link against the debug version of libstdc++?

The reason I am asking this is that I have a program which throws a
segmentation fault when an exception is thrown. However, in that case,
there is an exception handler that is in my program. The exact same
program runs fine under Microsoft's c++ compiler on Windows
but crashes horribly with a SIGSEGV under Linux.

It is further complicated by the fact that the program uses gcc 2.96 ...

The stack trace for that shows the stack is not being unwound properly, it
seems to be going of to functions which were not even on the call stack!

It seems that gcc 2.96 (and libstdc++) had some problems with exception
handling code (mentioned at 
http://rhn.redhat.com/errata/RHBA-2002-055.html).
However, even installing these patches did not help.

Any suggestions to tackle this problem would be very helpful ...

Cheers,
Naam Nahin