diff --git a/src/lisp.h b/src/lisp.h
index 400dc8d639a..d6c4a1ba609 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -2469,8 +2469,8 @@ EXFUN (Fding, 1);
 EXFUN (Fredraw_frame, 1);
 EXFUN (Fredraw_display, 0);
 EXFUN (Fsleep_for, 2);
-EXFUN (Fsit_for, 3);
-extern Lisp_Object sit_for P_ ((int, int, int, int, int));
+EXFUN (Fredisplay, 1);
+extern Lisp_Object sit_for P_ ((Lisp_Object, int, int));
 extern void init_display P_ ((void));
 extern void syms_of_display P_ ((void));
 extern void safe_bcopy P_ ((const char *, char *, int));