Comment 7 for bug 630680

Sorry: the finalizer's:

    (when (and auto-close (fboundp 'finalize))
      (finalize stream
                (lambda ()
                  (sb!unix:unix-close fd)
                  #!+sb-show
                  (format *terminal-io* "** closed file descriptor ~W **~%"
                          fd))
                :dont-save t))

I meant, if it was something like this:

(defun finalize-close-fd (fd)
  (sb!unix:unix-close fd)
  #!+sb-show
  (format *terminal-io* "** closed file descriptor ~W **~%"
          fd))
[...]
      (finalize stream
                (lambda ()
                  (finalize-close-fd fd))
                :dont-save t))

You could easily do (trace sb-impl::finalize-close-fd :break t).