diff --git a/src/list.h b/src/list.h
index 8f32785..d608deb 100644
--- a/src/list.h
+++ b/src/list.h
@@ -133,7 +133,7 @@ static __inline__ void list_splice(struct list_head *list, struct list_head *hea
  * @member:	the name of the list_struct within the struct.
  */
 #define list_entry(ptr, type, member) \
-	((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
+	((type *)((char *)(ptr)-(size_t)(&((type *)0)->member)))
 
 /**
  * list_for_each	-	iterate over a list