Filew.copy_channels

let copy_channels ?(bufsz = 4096) inch outch =
  if (bufsz < 0) || (bufsz > Sys.max_string_length)
  then invalid_arg "Filew.copy_channels: bufsz"
  else
    (let buf = String.make bufsz '\x00' in
     let rec inner () =
       let have_read = input inch buf 0 bufsz
       in
         if have_read = 0
         then ()
         else (output outch buf 0 have_read; inner ())
     in inner ())