diff --git a/include/my_sys.h b/include/my_sys.h
index 7e6a51ff21f..315d2f5c08d 100644
--- a/include/my_sys.h
+++ b/include/my_sys.h
@@ -246,7 +246,7 @@ extern int NEAR my_umask,		/* Default creation mask  */
 	   NEAR my_safe_to_handle_signal, /* Set when allowed to SIGTSTP */
 	   NEAR my_dont_interrupt;	/* call remember_intr when set */
 extern my_bool NEAR mysys_uses_curses, my_use_symdir;
-extern ulong sf_malloc_cur_memory, sf_malloc_max_memory;
+extern size_t sf_malloc_cur_memory, sf_malloc_max_memory;
 
 extern ulong	my_default_record_cache_size;
 extern my_bool NEAR my_disable_locking,NEAR my_disable_async_io,