GTK3 - Monitoring all signals emitted from a widget

Question

Is there any way to monitor all signals emitted from a widget with GTK3? I know that the event signal is emitted before an event, but I'm not sure of the distinction between "event" and "signal" in GTK terminology - as this does not seem to capture all signals.

I know GDK has a function gdk_set_show_events but this mostly shows events which are sent to the window from the operating system. Is there a GTK3 equivalent?

Answer 1

There is not built in function AFAIK, but I'm sure you can hack something together yourself:

Use g_signal_lookup to get all signal ids for a gtype. Then use g_signal_add_emission_hook on each signal of your instance to register a hook to be called whenever that particular signal is emitted. Inside the hook function, you're provided with the signal id via *ihint, from which g_signal_query should provide you with all the information you need to print debug messages. (I didn't test it, but it should work)

Note that this will unfortunately not work for signals defined with G_SIGNAL_NO_HOOKS.

Answer 2

Use g_signal_lookup to get all signal ids

It's a little more complicated than described. In order to use g_signal_lookup, you first need a signal-name. If you want to monitor every signal independent of the object-type, you first need to list all signals of the specific instance-type. This can be arranged by g_signal_list_ids for exactly one single GType. To get really ALL signals emitted on the instance, you need to iterate over all parent-types of this instance. You can do this by using g_type_parent.

I have build some utility-functions by myself, that provide this functionality for the same debugging purpose the question was intended. You can connect an Emission-Hook for all signals of a GObject-instance with gemu_glib_util_connect_to_all_signals or connect an emission-Hook to a GtkWidget-instance and all its children with gemu_gtk_util_signal_connect_to_widget_children.