A POSIX question
I posted the following to superuser.com, and put about a third of the reputation points I had into it:

Impossible paths
Are there any legal paths in POSIX that cannot be associated with a file, regular or irregular? That is, for which test -e "$LEGITIMATEPOSIXPATHNAME" cannot succeed?

I'm not very impressed by the smartness or helpfulness of answers there, so I doubt that I will get adequate responses. I should just read the standards, but I am not feeling unlazy.

Oh, ... and a Happy New Year, Advogato!

Postscript
It turns out that /dev/tty/impossible is impossible, since POSIX says that /dev/tty must be a character device file, and I understand that paths can only be the dirname of a file if they are directories or symlinks. The answerer I awarded my bounty on at SU didn't figure that out, but he gave me a clue that helped me.