From: Florian Weimer <fw@deneb.enyo.de>
To: John Love-Jensen <eljay@adobe.com>
Cc: Claudio Bley <bley@cs.uni-magdeburg.de>,
Joshua Nye <josh@boxcarmedia.com>, Steve Dondley <s@dondley.com>,
<gcc-help@gcc.gnu.org>
Subject: Re: Avoiding "assignment from incompatible pointer type" warning
Date: Mon, 21 Oct 2002 06:52:00 -0000 [thread overview]
Message-ID: <87d6q3vr09.fsf@deneb.enyo.de> (raw)
In-Reply-To: <B9D96E10.5411%eljay@adobe.com> (John Love-Jensen's message of "Mon, 21 Oct 2002 08:40:48 -0500")
John Love-Jensen <eljay@adobe.com> writes:
>> I can't see why. Can you elaborate on that? I mean, casting on the
>> machine code level does just nothing - it's just "syntactic sugar" to
>> convince the compiler to be quiet. I think casting from one pointer
>> type to another does no harm at all. Am I wrong?
>
> You are correct, the casting is fine, insofar as the given code snippet
> goes.
>
> I assume the complaint/concern was regarding the (presumed)
> dereferencing of the int* p at some later point in the code.
Oh, please. An implementation is free to consider such pointer
conversions to be undefined (of course, an implementation may do
something useful nevertheless), so it's essentially undefined. And
the undefined behavior is triggered upon the cast, not when the
pointer is dereferenced.
6.3.2.3(7) only ensures that conforming implementations may not issue
a diagnostic for such programming errors.
next prev parent reply other threads:[~2002-10-21 13:52 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-10-13 9:08 Steve Dondley
2002-10-13 9:28 ` Joshua Nye
2002-10-13 9:34 ` Steve Dondley
2002-10-13 15:09 ` Florian Weimer
2002-10-13 15:19 ` Joshua Nye
2002-10-15 11:24 ` Joshua Nye
2002-10-21 3:12 ` Florian Weimer
2002-10-21 4:22 ` Claudio Bley
2002-10-21 4:30 ` Florian Weimer
2002-10-21 6:48 ` Claudio Bley
2002-10-21 4:42 ` Sebastian Huber
2002-10-21 6:43 ` John Love-Jensen
2002-10-21 6:52 ` Florian Weimer [this message]
2002-10-13 13:37 Moore, Mathew L
2002-10-13 15:10 ` Florian Weimer
2002-10-21 6:07 Moore, Mathew L
2002-10-21 7:04 Moore, Mathew L
2002-10-21 7:17 ` Florian Weimer
2002-10-21 7:43 ` John Love-Jensen
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