diff --git a/libudev/libudev-device.c b/libudev/libudev-device.c
index 4717b582b..add1c99ec 100644
--- a/libudev/libudev-device.c
+++ b/libudev/libudev-device.c
@@ -577,7 +577,7 @@ struct udev_device *udev_device_get_parent(struct udev_device *udev_device)
  * value, and fill in information from the sys device and the udev
  * database entry.
  *
- * If devtype is NULL, only subsystem is checked, and any devtype will
+ * If devtype is #NULL, only subsystem is checked, and any devtype will
  * match.
  *
  * The returned the device is not referenced. It is attached to the