diff --git a/ext/fiddle/fiddle.c b/ext/fiddle/fiddle.c
index 08fdb4484d..83c0bb5e1e 100644
--- a/ext/fiddle/fiddle.c
+++ b/ext/fiddle/fiddle.c
@@ -2,7 +2,8 @@
 
 VALUE mFiddle;
 
-void Init_fiddle()
+void
+Init_fiddle(void)
 {
     /*
      * Document-module: Fiddle