(0) mm@lila:~% gdb gnome-settings-daemon
(no debugging symbols found)
Using host libthread_db library "/lib/tls/libthread_db.so.1".
(gdb) b gdk_x_error
Function "gdk_x_error" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (gdk_x_error) pending.
(gdb) r --sync
Starting program: /usr/bin/gnome-settings-daemon --sync
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
[Thread debugging using libthread_db enabled]
[New Thread -1224915264 (LWP 13729)]
[New Thread -1225032784 (LWP 13736)]
The program 'gnome-settings-daemon' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadValue (integer parameter out of range for operation)'.
  (Details: serial 20921 error_code 2 request_code 116 minor_code 0)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the --sync command line
   option to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)
[1134160312,000,xklavier.c:XklStartListen/]     The backend does not require manual layout management - but it is provided by the application
Program exited with code 01.
(gdb)