From: Andy Wingo <wingo@pobox.com>
To: ludo@gnu.org (Ludovic Courtès)
Cc: guile-devel <guile-devel@gnu.org>
Subject: Re: modifying pointers
Date: Fri, 09 Apr 2010 22:15:21 +0200 [thread overview]
Message-ID: <m3tyrkpeli.fsf@pobox.com> (raw)
In-Reply-To: <87fx34mmt4.fsf@gnu.org> ("Ludovic Courtès"'s message of "Fri, 09 Apr 2010 21:46:15 +0200")
Hi!
On Fri 09 Apr 2010 21:46, ludo@gnu.org (Ludovic Courtès) writes:
> Andy Wingo <wingo@pobox.com> writes:
>
>> I'm just wondering if it is valid to create a ((void*) 777) pointer.
>> Under what condition is that useful?
>
[...]
> It opens the door to all sorts of crazy things. :-)
Cool :)
FWIW, let's kick that door off its hinges :-)))
>> If that is useful, OK; but under what condition is it useful to mutate
>> the pointer in a foreign pointer object? Why not create a new foreign
>> pointer object?
>
> There’s currently no procedure to create a foreign object from a
> bignum.
Perhaps we should define one then. It would be more expressive. Also it
avoids all kinds of shared-state problems.
> (Besides, ‘foreign-set!’ exists and has always been defined for all
> types of foreign pointer objects.)
Sure, but this might be an accident. In every case except `void',
foreign-set! modifies the pointed-to memory. Perhaps we need a
foreign-pointer accessor instead, which would work on pointers to values
as well. And a constructor of course.
Andy
--
http://wingolog.org/
prev parent reply other threads:[~2010-04-09 20:15 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-09 9:05 modifying pointers Andy Wingo
2010-04-09 16:30 ` Ludovic Courtès
2010-04-09 16:59 ` Andy Wingo
2010-04-09 19:46 ` Ludovic Courtès
2010-04-09 20:15 ` Andy Wingo [this message]
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