val seek_out : Caml.out_channel -> int64 -> unitval pos_out : Caml.out_channel -> int64val out_channel_length : Caml.out_channel -> int64val seek_in : Caml.in_channel -> int64 -> unitval pos_in : Caml.in_channel -> int64val in_channel_length : Caml.in_channel -> int64