Re: HELP: GLib-GObject-WARNING **: instance of invalid non-instantiatable type `(null)'

[Emmanuele Bassi <ebassi gmail com>]

On Wed, 2007-05-23 at 12:56 +0200, Guenther Meyer wrote:

> > > GLib-GObject-WARNING **: instance of invalid non-instantiatable type
> > > `(null)'
> > >
> > > GLib-GObject-CRITICAL **: g_signal_emit_valist: assertion
> > > `G_TYPE_CHECK_INSTANCE (instance)' failed
> > >
> > > and sometimes the application segfaults after this.


it means you're trying to access a widget long after it has been
destroyed.

> > And use gdb, since you get segfaults, have you tried to at
> > least print backtrace to see where it crashes?
> >
> >   gdb program core.12345
> >   backtrace
> yes, but that doesn't really help me...

if you are developing with GTK+ it helps a lot to have debug symbols
installed so that gdb can return a meaningful stack trace. you should
follow your distribution's guidelines on how to install packages with
debug symbols for glib and gtk+ at the very least.

after that, you should run your application under gdb, launching your
application with the --g-fatal-warnings command line switch, which will
tell gtk+ to abort() as soon as a  warning is issued. this will make
tracing where the bug happens a lot easier.

ciao,
 Emmanuele.

-- 
Emmanuele Bassi,  E: ebassi gmail com
W: http://www.emmanuelebassi.net
B: http://log.emmanuelebassi.net