%N xyzflush %F $MIR/src/subs/xyzio.c
%D Force output buffer to be written to disk
%P bpw
%: image-i/o
%B
      subroutine xyzflush( tno )
      integer    tno

This flushes the output buffer to disk, just like when closing a dataset.
However, the dataset remains open. This is intended for usage where there
is a limit on the number of open datasets, so that one cannot have them
open all at the same time, and then do all setups once.

   Input:
      tno:     The image-file handle                                          
