GObject.SignalEmissionHook

function onSignalEmissionHook(ihint: GObject.SignalInvocationHint, param_values: Array(Any), data: void): Boolean {
}

A simple function pointer to get invoked when the signal is emitted. This allows you to tie a hook to the signal type, so that it will trap all emissions of that signal, from any object.

You may not attach these to signals created with the #G_SIGNAL_NO_HOOKS flag.

ihint: Signal invocation hint, see GObject.SignalInvocationHint.
param_values: the instance on which the signal was emitted, followed by the parameters of the emission.
data: user data associated with the hook.
Returns: whether it wants to stay connected. If it returns false, the signal hook is disconnected (and destroyed).