From: Eli Zaretskii <eliz@gnu.org>
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: lekktu@gmail.com, eggert@cs.ucla.edu, emacs-devel@gnu.org
Subject: Re: Lisp object that refers to a C struct
Date: Thu, 18 Oct 2012 19:16:09 +0200 [thread overview]
Message-ID: <83sj9b1z1i.fsf@gnu.org> (raw)
In-Reply-To: <jwvr4owezjb.fsf-monnier+emacs@gnu.org>
> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: Juanma Barranquero <lekktu@gmail.com>, eggert@cs.ucla.edu, emacs-devel@gnu.org
> Date: Thu, 18 Oct 2012 08:33:59 -0400
>
> >> In that case, wouldn't it be better to have the integer be an index
> >> into a table, like Stefan suggested?
> > It's easy to do that (of course, at a price of some slightly more
> > complicated memory management),
>
> I don't understand why the memory management would care about which
> integer you use to represent file-watcher descriptors.
It doesn't. I meant the need to manage the table itself, grow it when
needed, etc.
> > but I think Stefan still prefers the "new object" solution.
>
> I generally like stronger types, so you're probably right, but an "index
> into a table" doesn't necessarily sound so terribly bad, if you have
> such a table anyway
I don't have a table. What I have is an association list. I used the
same method as Rüdiger in his inotify patch.
> (BTW, is this table usable by Lisp, e.g. can they get the list of
> current file-watchers?).
Yes, it's an alist. But it currently isn't exposed to Lisp, neither
as a variable nor via an API. It could be, of course. But since
Rüdiger didn't, and since we didn't discuss in detail how this feature
will be used from Lisp, I didn't want to introduce APIs whose
necessity is not clear.
> >> It's faster to check that it is in range than compare it with an
> >> arbitrarily long list of known pointers.
> > That's not what the code does. It calls Fassoc_quit to find the
I meant Fassoc, of course.
> > descriptor in the list of known live watches (which will still be
> > needed under the table suggestion),
>
> Isn't Fassoc_quit going to "compare it with an arbitrarily long list"?
> To me this "list of known live watches" sounds exactly like the "table"
> I mention above.
Yes, but since it's an alist, I get its memory management for free.
> > and then validates the pointer itself, just in case (which is also
> > independent of the table suggestion).
>
> What means "validate"?
Call w32_valid_pointer_p, and in addition verify that the struct
pointed to by it has the correct magic signature.
next prev parent reply other threads:[~2012-10-18 17:16 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
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 [this message]
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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