diff --git a/src/time.c b/src/time.c
index 692cef3..c82a79a 100644
--- a/src/time.c
+++ b/src/time.c
@@ -802,7 +802,7 @@
 
 # if defined(EXITFREE) || defined(PROTO)
     void
-timer_free_all()
+timer_free_all(void)
 {
     while (first_timer != NULL)
     {