sig val seek_out : Stdlib.out_channel -> int64 -> unit val pos_out : Stdlib.out_channel -> int64 val out_channel_length : Stdlib.out_channel -> int64 val seek_in : Stdlib.in_channel -> int64 -> unit val pos_in : Stdlib.in_channel -> int64 val in_channel_length : Stdlib.in_channel -> int64 end