Calling the GDestroyNotify function at GtkCustomFilter

Platform
1

I use a GtkCustomFilter in my program, and everything seems to work.
The filter is created with the following function.

GtkCustomFilter* filter = gtk_custom_filter_new ((GtkCustomFilterFunc) match_func, data, (GDestroyNotify)destroy_notify);

However, I have not yet managed to call up the function destroy_notify.
The documentation says:

“If a previous function was set, its user_destroy will be called now.”

What function does this mean?
match_func or gtk_filter_changed().

2

That means destroy_notify will be called on data.

3

Thank you for the answer. The point, however, is that the following function is never called. Why?

void destroy_notify(gpointer *data)
{
        g_print("Destroy_Notify\n");
}
4

The destroy function will be called when the GtkCustomFilter instance is finalized, which happens when the last reference held on the filter object is released.