void interface_add_error(struct interface *iface, const char *subsystem,
const char *code, const char **data, int n_data);
void interface_add_error(struct interface *iface, const char *subsystem,
const char *code, const char **data, int n_data);
void interface_queue_event(struct interface *iface, enum interface_event ev);
void interface_dequeue_event(struct interface *iface);
void interface_queue_event(struct interface *iface, enum interface_event ev);
void interface_dequeue_event(struct interface *iface);