diff --git a/include/stddef.h b/include/stddef.h
index 147949b..3f3f4fe 100755
--- a/include/stddef.h
+++ b/include/stddef.h
@@ -19,4 +19,6 @@
 #include <types/size_t.h>
 #include <types/wchar_t.h>
 
+#define offsetof(type, member) (size_t)(&((type *)0->member))
+
 #endif