🚀 go-pugleaf

I got a few mail replies on my question regarding where a file resides.
Some experimenting and combining the answers gave me a simple way to find
out if a file is on disk or a `terminal':

what I think is the easiest way to do it: if you seek to an illegal
position (like -1), you get an error (-64) if the file is on disk,
otherwise you get 0. If the file is on disk, its position is not changed,
so the operation is effectively always a no-op. So I use:

isatty (fd)
int fd;
{ return (Fseek (-1L, fd, 0) == 0); }

Please could any of the TOS developers comment on this?
-- 
Piet van Oostrum, Dept of Computer Science, University of Utrecht
Padualaan 14, P.O. Box 80.089, 3508 TB Utrecht, The Netherlands
Telephone: +31-30-531806              UUCP: ...!mcvax!ruuinf!piet