Using debug version of standard libraries

alexagr · 01-23-2008, 10:34 AM

I'm debugging my application under Debian 4.0 using DDD/GDB and many times the data produced by GDB backtrace is barely useful, 'cause i see something like

Code:

   #3  0xae550ac8 in ?? ()

As far as I understand the problem is that standard libraries, supplied with Debian are stripped. I found on the Web some post that suggest running the program against non-stripped libraries version by doing:

Code:

   LD_LIBRARY_PATH=/usr/lib/debug
   export LD_LIBRARY_PATH

prior to running the program.

Unfortunately when I do that, my program fails at the following line (that works perfectly fine with normal libraries):

Code:

   m_Semaphore = sem_open("/ipmgr",O_RDWR | O_CREAT,0666,1);

I get SEM_FAILED and errno is set to EINVAL, which means that value (1) is too big (pretty absurd).

Is there anything that I'm doing wrong?
Thank you in advance,
Alex

traene · 02-07-2008, 02:04 PM

I'd say in many cases you don't need to use the debug version of the libraries. Try to compile your programme with opitmizations turned off:

CC_FLAGS=-O0

alexagr · 02-08-2008, 10:25 AM

Thank you for your response.
Unfortunately turning optimization off doesn't really help me...

I noticed that when I normally run "getconf GNU_LIBPTHREAD_VERSION", I get "NPTL 2.3.6" output. But when I set LD_LIBRARY_PATH to point to the debug libraries, the same command returns "linuxthreads-0.10". Does it mean that debug version of the libraries lacks NPTL support? Can it be the source of my problem?

traene · 02-08-2008, 04:07 PM

What distro do you use? Can you verify what packets of the glibc you have installed? I think you can call he library like so:
/lib/libc.so

this will print some infos of the library like version and components. Check the threads.
When you set your LD_LIBRARY_PATH you can also check the contents of your debug lib. Sounds like different versions to me.

cetialphav · 02-08-2008, 10:03 PM

Does Debian have debug packages for the libc stuff? I use Fedora, and they provide special rpms that allow you to debug into any of the supplied packages. It is really handy. To install them you run something like:

Code:

debuginfo-install glibc

And that installs the files you need to be able to debug into the C libraries

Code:

[todd@hobbes ush]$ rpm -qa | grep debuginfo
gcc-debuginfo-4.1.2-33
glibc-debuginfo-2.7-2
glibc-debuginfo-common-2.7-2

Now I don't know Debian, but I would think they would have a similar facility.