diff --git a/sys/sys/aio.h b/sys/sys/aio.h
--- a/sys/sys/aio.h
+++ b/sys/sys/aio.h
@@ -239,7 +239,7 @@
  *	when all I/Os are complete, the optional signal "sig" is sent.
  */
 int	lio_listio(int, struct aiocb *__restrict const *__restrict, int,
-    struct sigevent *);
+    struct sigevent *__restrict);
 
 /*
  * Get completion status