diff --git a/src/quickfix.c b/src/quickfix.c
index 245e20b..63dd541 100644
--- a/src/quickfix.c
+++ b/src/quickfix.c
@@ -8448,7 +8448,7 @@
 
 # if defined(EXITFREE) || defined(PROTO)
     void
-free_quickfix()
+free_quickfix(void)
 {
     win_T	*win;
     tabpage_T	*tab;