[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
weak key hash versus display
From: |
Kevin Ryde |
Subject: |
weak key hash versus display |
Date: |
Thu, 30 Jan 2003 09:21:15 +1000 |
User-agent: |
Gnus/5.090013 (Oort Gnus v0.13) Emacs/21.2 (i386-pc-linux-gnu) |
In guile 1.6.1 or the cvs on a recent i386 debian, I noticed that
doing a display of a weak key hash table can seemingly prevent a key
from being garbage collected. For instance
(define h (make-weak-key-hash-table 7))
(define k "mykey")
(hash-set! h (string-copy k) 12345)
(display (hash-ref h k)) (newline)
(display h) (newline)
(gc)
(display (hash-ref h k)) (newline)
run with "guile -s foo.scm" produces
12345
#wh(() () () () () ((mykey . 12345)) ())
12345
whereas I might have expected the gc to have collected the entry just
set, making the second hash-ref give #f rather than 12345. This is
what happens if the (display h) is not present.
I don't really know if this is a bug, or ignorance on my part, but it
seemed more than a little strange.
- weak key hash versus display,
Kevin Ryde <=