void g_signal_override_class_closure ( guint signal_id, GType instance_type, GClosure* class_closure )
Overrides the class closure (i.e. the default handler) for the given signal
for emissions on instances of
instance_type must be derived
from the type to which the signal belongs.
g_signal_chain_from_overridden_handler() for how to chain up to the
parent class closure from inside the overridden one.
The signal id.
The instance type on which to override the class closure for the signal.
The data is owned by the caller of the function.