`g_signal_connect_swapped(instance, detailed_signal, c_handler, data);`connects a
GCallbackfunction to a signal for a particular object. The instance on which the signal is emitted and data will be swapped when calling the handler.
不大理解上面讲的,是说instance将指向*data,而data将指向*instance吗?
如果是,这样做有什么好处?
