+ if (udev_monitor_filter_add_match_subsystem(udev_monitor, "block") < 0 ||
+ udev_monitor_filter_add_match_subsystem(udev_monitor, "tty") < 0 ||
+ udev_monitor_filter_add_match_subsystem(udev_monitor, "usb") < 0) {
+ printf("filter failed\n");
+ return -1;
+ }