diff --git a/lib/libc/gen/arc4random.3 b/lib/libc/gen/arc4random.3
index 42bb413117f..25c6d4d0a02 100644
--- a/lib/libc/gen/arc4random.3
+++ b/lib/libc/gen/arc4random.3
@@ -44,7 +44,7 @@
 .Ft void
 .Fn arc4random_stir "void"
 .Ft void
-.Fn arc4random_addrandom "u_char *dat" "int datlen"
+.Fn arc4random_addrandom "unsigned char *dat" "int datlen"
 .Sh DESCRIPTION
 The
 .Fn arc4random