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Date: Mon, 11 Nov 2002 22:39:24 +0000
From: David Malone <dwmalone@maths.tcd.ie>
To: Harti Brandt <brandt@fokus.gmd.de>
Cc: Andrew Gallatin <gallatin@cs.duke.edu>,
	FreeBSD-current@FreeBSD.ORG
Subject: Re: gcc 3.2.1 optimization bug ?
Message-ID: <20021111223924.GA30568@walton.maths.tcd.ie>
References: <15823.48873.236346.943980@grasshopper.cs.duke.edu> <20021111163918.Y13339-100000@beagle.fokus.gmd.de>
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On Mon, Nov 11, 2002 at 04:52:22PM +0100, Harti Brandt wrote:
AG>But does using a union make it safe?

> Well, I just had a long discussion with a collegue about the topic. The
> main problem is in the ISO-C standard, section 6.7 point 4 which states:
> 
> All declarations in the same scope that refer to the same object or
> function shall specify compatible types.

I think Section 6.5 paragraph 7 allows access through unions. There
is a footnote saying that the list given (which includes access
through the same type, qualified versions of the same type, aggregates
and unions containign that type and character types) is intended
for determining aliasing rules.

	David.

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