GNU libavl 2.0.1
Author: Ben Pfaff

7.8.2 Starting at the First Node |

    270. <TBST traverser first initializer 270> =
    void *
    tbst_t_first (struct tbst_traverser *trav, struct tbst_table *tree)
    {
      assert (tree != NULL && trav != NULL);

      trav->tbst_table = tree;
      trav->tbst_node = tree->tbst_root;
      if (trav->tbst_node != NULL)
        {
          while (trav->tbst_node->tbst_tag[0] == TBST_CHILD)
            trav->tbst_node = trav->tbst_node->tbst_link[0];
          return trav->tbst_node->tbst_data;
        }
      else
        return NULL;
    }

This code is included in 268.

7.8.1 Starting at the Null Node | 7.8 Traversal | 7.8.3 Starting at the Last Node