diff --git a/include/uv.h b/include/uv.h
index baa0b2812..78df97b2b 100644
--- a/include/uv.h
+++ b/include/uv.h
@@ -1465,6 +1465,7 @@ struct uv_loop_s {
   void* active_reqs[2];
   /* Internal flag to signal loop stop. */
   unsigned int stop_flag;
+  void* reserved[4];
   UV_LOOP_PRIVATE_FIELDS
 };