all messages for Emacs-related lists mirrored at yhetil.org
 help / color / mirror / code / Atom feed
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.



  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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=83ipa92i95.fsf@gnu.org \
    --to=eliz@gnu.org \
    --cc=emacs-devel@gnu.org \
    --cc=monnier@IRO.UMontreal.CA \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
Code repositories for project(s) associated with this external index

	https://git.savannah.gnu.org/cgit/emacs.git
	https://git.savannah.gnu.org/cgit/emacs/org-mode.git

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.