A #GClosure.
A #GValue to store the return value. May be %NULL if the callback of closure doesn't return a value.
The length of the @param_values array.
An array of #GValues holding the arguments on which to invoke the callback of closure.
The invocation hint given as the last argument to g_closure_invoke().
Additional data specified when registering the marshaller, see g_closure_set_marshal() and g_closure_set_meta_marshal()
A #GClosureMarshal function for use with signals with handlers that take a #GObject and a pointer and produce a string. It is highly unlikely that your signal handler fits this description.