Re: Gdk::Window::add_filter

[Murray Cumming <murrayc murrayc com>]

On Thu, 2005-08-11 at 21:49 +0200, Marcus Lundblad wrote:
> I'm trying to add an event filter function to intercept raw X messages 
> (listening to messages on the root window).
> 
> I have the following code at this point:
> 
> -------------------------------------------------------
> 
> GdkFilterReturn filter_func(GdkXEvent *xevent,
>  			    GdkEvent *event,
>  			    gpointer data)
> {
>    return GDK_FILTER_TRANSLATE;
> }
> 
> main_window::main_window()
> {
>    gpointer data = (gpointer*) new char [1024];
> 
>    get_window()->add_filter(filter_func, data);
> 
> -------------------------------------------------------
> 
> where main_window inherits from Gtk::Window
> but there occurs a segmentation fault (this is on GNU/Linux) at the call 
> to "add_filter".
> I don't understand why it segfaults at this call (I could understand if it 
> cores when the callback is called, but according to gdb it happens at (or 
> in) the "add_filter" call).
> Maybe I'm doing something obviously wrong, but I don't see it.
> What is there supposed to be where "data" points at, is it arbitrary 
> data?

Maybe it would be helpful to show us the backtrace. Also, valgrind would
probably be helpful.

-- 
Murray Cumming
murrayc murrayc com
www.murrayc.com
www.openismus.com