signalLookup
Given the name of the signal and the type of object it connects to, gets the signal's identifying integer. Emitting the signal by number is somewhat faster than using the name each time.
Also tries the ancestors of the given type.
The type class passed as @itype must already have been instantiated (for example, using g_type_class_ref()) for this function to work, as signals are always installed during class initialization.
See g_signal_new() for details on allowed signal names.
Return
the signal's identifying number, or 0 if no signal was found.
Parameters
name
the signal's name.
itype
the type that the signal operates on.