From: Eli Zaretskii <eliz@gnu.org>
To: Stefan Monnier <monnier@IRO.UMontreal.CA>
Cc: emacs-devel@gnu.org
Subject: Re: Lisp object that refers to a C struct
Date: Wed, 17 Oct 2012 18:08:54 +0200 [thread overview]
Message-ID: <83ipa92i95.fsf@gnu.org> (raw)
In-Reply-To: <jwvsj9dxlxe.fsf-monnier+emacs@gnu.org>
> From: Stefan Monnier <monnier@IRO.UMontreal.CA>
> Cc: emacs-devel@gnu.org
> Date: Wed, 17 Oct 2012 09:34:40 -0400
>
> >> What happens if someone passes you this same integer some time after
> >> you've freed the C struct?
> > It won't be found in the list of watches, so the command to remove
> > that watch will say "Invalid watch descriptor", and Lisp-level code
> > will not find the corresponding Lisp data structure.
>
> So the integer doesn't encode the pointer, instead it's an index into
> a table of C structs.
No, I have no table right now. I could add one, of course.
Right now, the struct is allocated and its pointer is put into an
alist as a Lisp integer, and also returned, as a Lisp integer, to the
caller of the "start-watching" API. The caller is supposed to manage
her watches, and pass the right integer when she wants to cancel a
watch.
next prev parent reply other threads:[~2012-10-17 16:08 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-15 21:24 Lisp object that refers to a C struct Eli Zaretskii
2012-10-16 1:07 ` Stefan Monnier
2012-10-16 3:53 ` Eli Zaretskii
2012-10-16 13:11 ` Stefan Monnier
2012-10-16 17:22 ` Eli Zaretskii
2012-10-16 21:43 ` Stefan Monnier
2012-10-17 4:05 ` Eli Zaretskii
2012-10-17 6:21 ` Stephen J. Turnbull
2012-10-17 15:50 ` Eli Zaretskii
2012-10-17 17:45 ` Stephen J. Turnbull
2012-10-17 13:34 ` Stefan Monnier
2012-10-17 16:08 ` Eli Zaretskii [this message]
2012-10-17 20:23 ` Stefan Monnier
2012-10-17 20:46 ` Eli Zaretskii
2012-10-17 22:08 ` Paul Eggert
2012-10-18 0:22 ` Stefan Monnier
2012-10-18 3:43 ` Stephen J. Turnbull
2012-10-18 4:50 ` Eli Zaretskii
2012-10-18 7:20 ` Paul Eggert
2012-10-18 11:09 ` Eli Zaretskii
2012-10-18 16:42 ` Paul Eggert
2012-10-18 17:21 ` Eli Zaretskii
2012-10-18 8:52 ` Juanma Barranquero
2012-10-18 11:17 ` Eli Zaretskii
2012-10-18 12:33 ` Stefan Monnier
2012-10-18 17:16 ` Eli Zaretskii
2012-10-18 22:09 ` Stefan Monnier
2012-10-19 7:14 ` Eli Zaretskii
2012-10-19 14:44 ` Stefan Monnier
2012-10-19 18:54 ` Eli Zaretskii
2012-10-19 21:35 ` Stefan Monnier
2012-10-19 22:35 ` Eli Zaretskii
2012-10-20 1:52 ` Stefan Monnier
2012-10-20 8:34 ` Eli Zaretskii
2012-10-17 16:05 ` Eli Zaretskii
2012-10-17 16:59 ` Davis Herring
2012-10-17 20:27 ` Stefan Monnier
2012-10-17 21:02 ` Eli Zaretskii
2012-10-18 0:23 ` Stefan Monnier
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