diff --git a/lib/libutil/logout.3 b/lib/libutil/logout.3
index 2f62b4d2f4e..dd083abb6b6 100644
--- a/lib/libutil/logout.3
+++ b/lib/libutil/logout.3
@@ -37,7 +37,7 @@
 .Fd #include <sys/types.h>
 .Fd #include <libutil.h>
 .Ft int
-.Fn logout "char *line"
+.Fn logout "const char *line"
 .Sh DESCRIPTION
 The function
 .Fn logout