-struct avl_node *EXPORT(avl_find)(struct avl_tree *, const void *);
-struct avl_node *EXPORT(avl_find_greaterequal)(struct avl_tree *tree, const void *key);
-struct avl_node *EXPORT(avl_find_lessequal)(struct avl_tree *tree, const void *key);
+struct avl_node *EXPORT(avl_find)(const struct avl_tree *, const void *);
+struct avl_node *EXPORT(avl_find_greaterequal)(const struct avl_tree *tree, const void *key);
+struct avl_node *EXPORT(avl_find_lessequal)(const struct avl_tree *tree, const void *key);