Francois-Rene Rideau wrote:
> Robert told me that in some Unix flavors of old,
> it was possible to open a file by path with a null access mode (O_NULL ?)

E.g. Linux. Very undocumented, but has been around for ages ('92 or
such). The main purpose is to keep the floppy drive from spinning up
to check for a media change when you open it to access parameters and
such. E.g. fdformat, setfdprm, and LILO use this. (NB: some versions
of strace print the flags argument in this case as "0x4", although
it's really 3.)

- Werner

-- 
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 / Werner Almesberger, ICA, EPFL, CH       werner.almesberger@ica.epfl.ch /
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