diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 1dab501..c57db94 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -8491,7 +8491,7 @@
 }
 
 #ifdef FEAT_PERSISTENT_UNDO
-    void
+    static void
 ex_wundo(eap)
     exarg_T *eap;
 {
@@ -8501,7 +8501,7 @@
     u_write_undo(eap->arg, eap->forceit, curbuf, hash);
 }
 
-    void
+    static void
 ex_rundo(eap)
     exarg_T *eap;
 {