-avl_iterator_t *avl_get_iterator (avl_tree_t *t);
-int avl_iterator_next (avl_iterator_t *iter, void **key, void **value);
-int avl_iterator_prev (avl_iterator_t *iter, void **key, void **value);
-void avl_iterator_destroy (avl_iterator_t *iter);
+c_avl_iterator_t *c_avl_get_iterator (c_avl_tree_t *t);
+int c_avl_iterator_next (c_avl_iterator_t *iter, void **key, void **value);
+int c_avl_iterator_prev (c_avl_iterator_t *iter, void **key, void **value);
+void c_avl_iterator_destroy (c_avl_iterator_t *iter);
+
+/*
+ * NAME
+ * c_avl_size
+ *
+ * DESCRIPTION
+ * Return the size (number of nodes) of the specified tree.
+ *
+ * PARAMETERS
+ * `t' AVL-tree to get the size of.
+ *
+ * RETURN VALUE
+ * Number of nodes in the tree, 0 if the tree is empty or NULL.
+ */
+int c_avl_size (c_avl_tree_t *t);