From: Wolfgang Denk <wd@denx.de>
To: Bret Indrelee <Bret.Indrelee@qlogic.com>
Cc: Kent Borg <kentborg@borg.org>, linuxppc-embedded@lists.linuxppc.org
Subject: Re: IO, ANSI vs GCC structs
Date: Fri, 25 Jul 2003 18:19:35 +0200 [thread overview]
Message-ID: <20030725161940.41FDEC602D@atlas.denx.de> (raw)
In-Reply-To: Your message of "Fri, 25 Jul 2003 10:51:19 CDT." <Pine.LNX.4.44.0307251038370.22864-100000@spider.ancor.com>
In message <Pine.LNX.4.44.0307251038370.22864-100000@spider.ancor.com> you wrote:
>
> > Does GCC make guarantees beyond what ANSI requires? Is there some
> > subtle detail that forces struct layout ("volatile" in the definition
> > perhaps)?
>
> There is nothing that guarentees this, in ANSI or GCC.
You can use "__attribute__ ((packed))" with GCC which guaratees you
control over the alignment used by the compiler (it will use the
smallest possible alignment = one byte for a variable, and one bit
for a field, unless you specify a larger value with the `aligned'
attribute).
Best regards,
Wolfgang Denk
--
Software Engineering: Embedded and Realtime Systems, Embedded Linux
Phone: (+49)-8142-4596-87 Fax: (+49)-8142-4596-88 Email: wd@denx.de
The human race has one really effective weapon, and that is laughter.
- Mark Twain
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
next prev parent reply other threads:[~2003-07-25 16:19 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-07-25 15:30 IO, ANSI vs GCC structs Kent Borg
2003-07-25 15:51 ` Bret Indrelee
2003-07-25 16:19 ` Wolfgang Denk [this message]
2003-07-25 17:47 ` Kent Borg
2003-07-25 19:22 ` Wolfgang Denk
2003-07-25 21:45 ` Paul Mackerras
[not found] <5.1.0.14.2.20030725123123.03855f58@mail.ebshome.net>
2003-07-25 19:59 ` Bret Indrelee
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