(Query Remaining Character Count)

  On input, Q obtains the number of characters remaining in the input
  record to be transferred during a read operation.  The following
  example uses the Q descriptor to determine the size of the input
  record:

     READ(5,'(Q,A)') LEN, REC(1:LEN)

  On output, the Q descriptor has no effect, except that the
  corresponding I/O item is skipped.