From: Steven J Abner <pheonix.sja@att.net>
To: newlib@sourceware.org
Subject: Re: newlib header breaks restricted pointers in C++
Date: Tue, 25 Jul 2023 19:48:22 -0400 [thread overview]
Message-ID: <M4MDYR.FLQ74Z6AM2JZ1@att.net> (raw)
In-Reply-To: <ZMAZA1r+fNty6/BK@calimero.vinschen.de>
[-- Attachment #1: Type: text/plain, Size: 2296 bytes --]
Curiosity killed the cat,
I might not understand, could you clarify. It mentions 'restrict is not
a keyword in C++'.
So doesn't #if __cpplusplus need to define 'restrict'. Additionally,
shouldn't the below mentioned
'#define'(s) include '__restrict__ ?
On Tue, Jul 25 2023 at 06:48:35 PM +0000, Corinna Vinschen
<vinschen@redhat.com> wrote:
> On Jul 25 19:46, Sebastian Huber wrote:
>> On 25.07.23 19:35, Corinna Vinschen wrote:
>> > Hi Bruno,
>> >
>> > On Jul 24 22:23, Bruno De Fraine wrote:
>> > > Hello,
>> > >
>> > > As an extension, GCC and clang offer C99-style restricted
>> pointers in C++ mode:
>> > > <https://gcc.gnu.org/onlinedocs/gcc/Restricted-Pointers.html>
>> > >
>> > > We notice that this extension is broken when including newlib
>> headers: restricted pointers are treated as ordinary pointers.
>> > >
>> > > We traced this to the following section of
>> newlib/libc/include/sys/cdefs.h:
>> > >
>> > > /*
>> > > * GCC 2.95 provides `__restrict' as an extension to C90 to
>> support the
>> > > * C99-specific `restrict' type qualifier. We happen to use
>> `__restrict' as
>> > > * a way to define the `restrict' type qualifier without
>> disturbing older
>> > > * software that is unaware of C99 keywords.
>> > > */
>> > > #if !(__GNUC__ == 2 && __GNUC_MINOR__ == 95)
>> > > #if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 199901
>> > > #define __restrict
>> > > #else
>> > > #define __restrict restrict
>> > > #endif
>> > > #endif
>> > >
>> > > While the GCC __restrict extension was indeed introduced in GCC
>> 2.95, it is not limited to this version; the extension is also not
>> limited to C90:
>> > > <https://gcc.gnu.org/gcc-2.95/c++features.html>
>> > Either way, the above has been taken from FreeBSD, and it is
>> still,
>> > as of today, the same expression as used in FreeBSDs sys/cdefs.h
>> > file.
>> >
>> > Seb, any input on this?
>>
>> I added a FreeBSD bug report:
>>
>> <https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=272723>
>
> Great, thanks! Do we want to wait for a FreeBSD solution, or do
> we want to change it now and, maybe, take the FreeBSD version later?
>
> Does anybody want to provide a git compatible patch?
>
>
> Thanks,
> Corinna
>
next prev parent reply other threads:[~2023-07-25 23:48 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-24 22:23 Bruno De Fraine
2023-07-25 17:35 ` Corinna Vinschen
2023-07-25 17:46 ` Sebastian Huber
2023-07-25 18:48 ` Corinna Vinschen
2023-07-25 23:48 ` Steven J Abner [this message]
2023-07-27 9:00 ` Corinna Vinschen
2023-07-28 14:15 ` Sebastian Huber
2023-07-28 14:42 ` Joel Sherrill
2023-07-31 11:04 ` Bruno De Fraine
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