sll_insert_head
extern status_t sll_insert_head(long nextoff, void **head, void *item);
#define SLL_INSERT(_head,_nextp,_item) sll_insert_head(offsetof(typeof(*_head),_nextp), (void **)&(_head), _item)
#define SLL_INSERT_TAIL(_head,_nextp,_item) sll_insert_head(offsetof(typeof(*_head),_nextp), (void **)&(_head), _item)