Completes a read or write session by closing the IFF handle.
The IFFHandle struct is ready for reuse in another session,
it's just to open it again with OpenIFF(). This function
also automatically cleans up if a read or write fails halfway through.
INPUTS
iff
Pointer to an IFFhandle struct previously opened with OpenIFF()
RESULT
NOTES
This function tells the custom stream handler to clean up
by sending it a IFFCMD_CLEANUP IFFStreamCmd.
This function checks that buffers for buffered streams
have been freed. This is not very elegant and should have been
done at an earlier stadium. It is not a real bug though.
HISTORY
07.03.1997 digulla
Added patch by Nils Hendrik to avoid problems when CloseIFF() is called after
OpenIFF() has failed.