diff --git a/udev/lib/libudev-private.h b/udev/lib/libudev-private.h
index 3eb3d7957fc..dc02a842b88 100644
--- a/udev/lib/libudev-private.h
+++ b/udev/lib/libudev-private.h
@@ -176,9 +176,9 @@ size_t util_path_encode(const char *src, char *dest, size_t size);
 size_t util_path_decode(char *s);
 void util_remove_trailing_chars(char *path, char c);
 size_t util_strpcpy(char **dest, size_t size, const char *src);
-size_t util_strpcpyl(char **dest, size_t size, const char *src, ...);
+size_t util_strpcpyl(char **dest, size_t size, const char *src, ...) __attribute__ ((sentinel));
 size_t util_strscpy(char *dest, size_t size, const char *src);
-size_t util_strscpyl(char *dest, size_t size, const char *src, ...);
+size_t util_strscpyl(char *dest, size_t size, const char *src, ...) __attribute__ ((sentinel));
 int udev_util_replace_whitespace(const char *str, char *to, size_t len);
 int udev_util_replace_chars(char *str, const char *white);
 int udev_util_encode_string(const char *str, char *str_enc, size_t len);