how can I get filename from file descriptor?

[Rahul Dhesi]

In article <11113 at smoke.BRL.MIL> gwyn at brl.arpa (Doug Gwyn) writes:
>Out-of-band data communication is hackish.

Out-of-band data communication is hackish if and only if it is designed
to be so.  In the limited case of an out-of-band EOF, only the
representation of the EOF need be out-of-band.  BSD already represents
EOF correctly in most places (so one can, for example, distinguish
between nothing read because of a non-blocking read finding nothing and
nothing read because a blocking read found something -- such as ^D --
representing EOF).  Unfortunately this mechanism is not general enough,
so a process writing to a pipe has no way of communicating the same
thing that a user at a tty can communicate by typing the EOF
character.

>There never HAS been an EOF in UNIX; it's always been a read()
>returning 0.  At least that is properly synchronized with the
>valid data.

I see no contradiction between EOF occurring and a read() returning 0
bytes.  For regular files at least EOF has a very real meaning.
Anywhere that you can have multiple logical files or messages on a
single data stream a non-stick EOF has a very useful meaning.
--
Rahul Dhesi <dhesi%cirrusl at oliveb.ATC.olivetti.com>
UUCP:  oliveb!cirrusl!dhesi