-hashtable_t * ht_alloc (cmp_fun_t cmp_fun, hash_fun_t hash_fun, clone_fun_t clone_fun);
-skiplist_t * sl_alloc (cmp_fun_t cmp_fun, hash_fun_t hash_fun, clone_fun_t clone_fun);
-list_t * ll_alloc (cmp_fun_t cmp_fun, hash_fun_t hash_fun, clone_fun_t clone_fun);
+hashtable_t * ht_alloc (const datatype_t *key_type);
+skiplist_t * sl_alloc (const datatype_t *key_type);
+list_t * ll_alloc (const datatype_t *key_type);