SessionState session_get_state(Session *u);
extern const sd_bus_vtable session_vtable[];
-int session_node_enumerator(sd_bus *bus, const char *path, char ***nodes, void *userdata);
-int session_object_find(sd_bus *bus, const char *path, const char *interface, void **found, void *userdata);
+int session_node_enumerator(sd_bus *bus, const char *path,void *userdata, char ***nodes, sd_bus_error *error);
+int session_object_find(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error);
char *session_bus_path(Session *s);
int session_send_signal(Session *s, bool new_session);