* and so on. Negative integers are used in order to count
* from the tail, -1 is the last element, -2 the penultimante
* and so on. If the index is out of range NULL is returned. */
* and so on. Negative integers are used in order to count
* from the tail, -1 is the last element, -2 the penultimante
* and so on. If the index is out of range NULL is returned. */