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From: Jonathan Wakely <jwakely.gcc@gmail.com>
To: Andreas Schwab <schwab@linux-m68k.org>
Cc: Florian Weimer via Gcc <gcc@gcc.gnu.org>,
	Florian Weimer <fweimer@redhat.com>,
	Ulrich Drepper <drepper@redhat.com>
Subject: Re: -Wformat and u8""
Date: Tue, 10 May 2022 14:27:12 +0100	[thread overview]
Message-ID: <CAH6eHdRFxHYe_sAQgvswX+Owpzhw_bh0MNsD++o9bVc-OePR9Q@mail.gmail.com> (raw)
In-Reply-To: <87levbkoj4.fsf@igel.home>

On Mon, 9 May 2022 at 11:09, Andreas Schwab wrote:
>
> On Mai 09 2022, Florian Weimer via Gcc wrote:
>
> > * Ulrich Drepper via Gcc:
> >
> >> t.cc: In function ‘int main()’:
> >> t.cc:5:24: warning: format string is not an array of type ‘char’ [-Wformat=]
> >>     5 |   printf((const char*) u8"test %d\n", 1);
> >>       |                        ^~~~~~~~~~~~~
> >
> > This is not an aliasing violation because of the exception for char,
> > right?  So the warning does not even highlight theoretical undefined
> > behavior.
> >
> > On the other hand, that cast is still quite ugly.  All string-related
> > functions in the C library currently need it.  It might obscure real
> > type errors.  Isn't this a problem with char8_t?
>
> In C++20, u8 literals have a distinct type, which is an incompatible
> change from C++17.

And the recommended way to deal with it is to use a cast as Ulrich did.

  reply	other threads:[~2022-05-10 13:27 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-09  9:15 Ulrich Drepper
2022-05-09  9:26 ` Florian Weimer
2022-05-09 10:04   ` Ulrich Drepper
2022-05-09 10:07   ` Andreas Schwab
2022-05-10 13:27     ` Jonathan Wakely [this message]
2022-05-10 17:48       ` Tom Honermann

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