From: Marek Polacek <polacek@redhat.com>
To: Florian Weimer <fweimer@redhat.com>
Cc: gcc@gcc.gnu.org
Subject: Re: -Wint-conversion, -Wincompatible-pointer-types, -Wpointer-sign: Are they hiding constraint C violations?
Date: Thu, 10 Nov 2022 13:43:22 -0500 [thread overview]
Message-ID: <Y21GSiOKUw86oXwf@redhat.com> (raw)
In-Reply-To: <87mt8ysm3y.fsf@oldenburg.str.redhat.com>
On Thu, Nov 10, 2022 at 07:25:21PM +0100, Florian Weimer via Gcc wrote:
> GCC accepts various conversions between pointers and ints and different
> types of pointers by default, issuing a warning.
>
> I've been reading the (hopefully) relevant partso f the C99 standard,
> and it seems to me that C implementations are actually required to
> diagnose errors in these cases because they are constraint violations:
> the types are not compatible.
It doesn't need to be a hard error, a warning is a diagnostic message, which
is enough to diagnose a violation of any syntax rule or constraint.
IIRC, the only case where the compiler _must_ emit a hard error is for #error.
> Is this interpretation correct?
>
> Sorry if this questions this is more appropriate for the gcc-help list.
>
> Thanks,
> Florian
>
Marek
next prev parent reply other threads:[~2022-11-10 18:43 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-10 18:25 Florian Weimer
2022-11-10 18:43 ` Marek Polacek [this message]
2022-11-10 19:16 ` Florian Weimer
2022-11-10 23:05 ` Jonathan Wakely
2022-11-10 23:33 ` Joseph Myers
2022-11-11 9:21 ` David Brown
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