+/**
+ * udev_monitor_filter_add_match_subsystem_devtype:
+ * @udev_monitor: the monitor
+ * @subsystem: the subsystem value to match the incoming devices against
+ * @devtype: the devtype value to match the incoming devices against
+ *
+ * The filter must be installed before the monitor is switched to listening mode.
+ *
+ * Returns: 0 on success, otherwise a negative error value.
+ */