gdb.error: No type named TypeNode

[Gaulouis Frenchy <gaulouis fr gmail com>]

Hello,

I use gdb to visualize data in my C programme.

I need to know the class name of my GObject from instance

I have python's script installed on my system where the function g_type_name_from_instance is define

So i do:
(gdb) python execfile("/usr/share/glib-2.0/gdb/glib.py")
(gdb) python execfile("/usr/share/glib-2.0/gdb/gobject.py")
__file__: gdb was not built with custom backtrace support, disabling.
(gdb) python gdb.lookup_type("TypeNode")
Traceback (most recent call last):
  File "<string>", line 1, in <module>
gdb.error: No type named TypeNode.
Error while executing Python code.

Can you help me ?

PS: I'am really sorry for my bad english and my low level