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From: ludo@gnu.org (Ludovic Courtès)
To: guile-user@gnu.org
Subject: Re: Parsing a struct within a struct
Date: Thu, 10 Mar 2011 22:36:43 +0100	[thread overview]
Message-ID: <8739mu64k4.fsf@gnu.org> (raw)
In-Reply-To: 20110309082419.GA6429@neko

Hi Aidan,

Aidan Gauland <aidalgol@no8wireless.co.nz> writes:

> On Tue, Mar 08, 2011 at 08:20:29PM +1300, Aidan Gauland wrote:
>> (parse-c-struct event-pointer
>>                 (list uint8 uint8 uint8
>>                       (list uint8 int int uint16 )))
>>
>
> It seemed to be an off-by-one(-byte) error.  There was padding to
> align (to 32-bits, I think) the sub-struct.
>
> This works on my 32-bit machine, but I suspect it is not portable.
>
> (parse-c-struct event-pointer
>                 (list uint8 uint8 uint8	uint8 ; Padding
>                       (list uint8 int int uint16 )))
>
> What would be a better, portable solution?  I suspect the `alignof'
> procedure is my friend here, but I don't understand how to use it.

The ‘alignof’ procedure was actually your enemy here.  ;-)

This patch should fix it (will be in 2.0.1):

  http://git.savannah.gnu.org/cgit/guile.git/commit/?h=stable-2.0&id=d82f8518b96bbfa4f29e03d922369c37b64824d9

Thanks!

Ludo’.

PS: Let us know when your game is ready.  :-)




  reply	other threads:[~2011-03-10 21:36 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-08  7:20 Parsing a struct within a struct Aidan Gauland
2011-03-09  8:24 ` Aidan Gauland
2011-03-10 21:36   ` Ludovic Courtès [this message]
2011-03-11  2:33     ` Aidan Gauland

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