diff --git a/include/metalsvm/stddef.h b/include/metalsvm/stddef.h
index 8af33b43..01ec7a3e 100644
--- a/include/metalsvm/stddef.h
+++ b/include/metalsvm/stddef.h
@@ -27,7 +27,7 @@
 extern "C" {
 #endif
 
-#define NULL 	0
+#define NULL 	((void*) 0)
 
 #ifdef __cplusplus
 }