READ-CHAR-NO-HANG Problem

["Stephen P. Smith" <ssmith@ruffles.nrtc.northrop.com>]

Has anyone noticed the erroneous behavior with the EOF processing
of READ-CHAR-NO-HANG?  It is *supposed* to behave differently than
LISTEN by returning a NIL if no character is available but
distinguishing an EOF with either an error or returning an EOF-VALUE.
However, it does not appear to work, as can be seen by evaling
the following (in 7.1 and 7.2):

(with-open-file (stream "AnyRandomTextFile" :direction :input)
   (loop for thing = (read-char-no-hang stream nil :eof)
         until (equal thing :eof)
         when (characterp thing)
           do (format t "~c" thing)
          else do
              (format t "~%Got ~s." thing)))

which shows that READ-CHAR-NO-HANG begins to return NIL after the
end-of-file is hit. 

Since this doesn't work, is there any other method to LISTEN on
a collection of streams (which can be files, windows, network links)
returning the ones that have characters available and/or have
gone to EOF.

--Steve Smith