-map_t * map_alloc (const map_impl_t *map_impl, const datatype_t *key_type);
-uint64_t map_get (map_t *map, void *key);
-uint64_t map_set (map_t *map, void *key, uint64_t new_val);
-uint64_t map_add (map_t *map, void *key, uint64_t new_val);
-uint64_t map_cas (map_t *map, void *key, uint64_t expected_val, uint64_t new_val);
-uint64_t map_replace (map_t *map, void *key, uint64_t new_val);
-uint64_t map_remove (map_t *map, void *key);
-uint64_t map_count (map_t *map);
-void map_print (map_t *map);
-void map_free (map_t *map);
-
-map_iter_t * map_iter_begin (map_t *map, void *key);
-uint64_t map_iter_next (map_iter_t *iter, void **key);
+typedef uint64_t map_key_t;
+typedef uint64_t map_val_t;
+
+map_t * map_alloc (const map_impl_t *map_impl, const datatype_t *key_type);
+map_val_t map_get (map_t *map, map_key_t key);
+map_val_t map_set (map_t *map, map_key_t key, map_val_t new_val);
+map_val_t map_add (map_t *map, map_key_t key, map_val_t new_val);
+map_val_t map_cas (map_t *map, map_key_t key, map_val_t expected_val, map_val_t new_val);
+map_val_t map_replace (map_t *map, map_key_t key, map_val_t new_val);
+map_val_t map_remove (map_t *map, map_key_t key);
+map_val_t map_count (map_t *map);
+void map_print (map_t *map);
+void map_free (map_t *map);
+
+map_iter_t * map_iter_begin (map_t *map, map_key_t key);
+map_val_t map_iter_next (map_iter_t *iter, map_key_t *key);