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From: "Alejandro Colomar (man-pages)" <alx.manpages@gmail.com>
To: Joseph Myers <joseph@codesourcery.com>
Cc: gcc@gcc.gnu.org, cfe-dev@lists.llvm.org
Subject: Re: ISO C3X proposal: nonnull qualifier
Date: Thu, 2 Dec 2021 21:31:42 +0100	[thread overview]
Message-ID: <03338dbf-878d-2910-c676-b0945a61a10d@gmail.com> (raw)
In-Reply-To: <3178a917-e9df-36eb-4382-f8aec7b678a2@gmail.com>

On 12/2/21 21:24, Alejandro Colomar (man-pages) wrote:
> 
>      #define nonnull_assign(nn, p)                         \
>      ({                                                    \
>          auto p_  = p;                                 \
>          auto nn_ = nn;                                \
>                                                                \
>          if (p_ == NULL)                               \
>              *nn_ = const_cast(typeof(nn_), p_);  \

D'oh, this check should be the opposite, of course :)

>                                                                \
>          p_ == NULL;                                   \
>      })
> 

And I forgot to mention, that this macro intentionally leaves the 
nonnull pointer (nn) uninitialized in the case of a NULL input pointer 
(p), so that the compiler can then warn about an uninitialized variable 
if it's used uninitialized.


Cheers,
Alex

-- 
Alejandro Colomar
Linux man-pages comaintainer; http://www.kernel.org/doc/man-pages/

  reply	other threads:[~2021-12-02 20:31 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-15 16:01 Alejandro Colomar (man-pages)
2021-11-15 16:30 ` Alejandro Colomar (man-pages)
2021-11-15 20:18 ` Joseph Myers
2021-11-15 21:09   ` Alejandro Colomar (man-pages)
2021-11-15 22:17     ` Joseph Myers
2021-11-15 22:35       ` Alejandro Colomar (man-pages)
2021-11-15 22:47         ` Joseph Myers
2021-11-16 12:34           ` Alejandro Colomar (man-pages)
2021-11-17  0:06             ` Alejandro Colomar (man-pages)
2021-11-20 16:47               ` Ping: " Alejandro Colomar (man-pages)
2021-11-23 11:32               ` [cfe-dev] " Dmitri Gribenko
2021-11-23 11:17             ` Dmitri Gribenko
2021-11-23 11:45               ` Alejandro Colomar (man-pages)
2021-11-23 12:45                 ` Dmitri Gribenko
2021-12-01 22:24                   ` Alejandro Colomar (man-pages)
2021-12-02  0:39                     ` Dmitri Gribenko
2021-12-02  1:00                       ` Alejandro Colomar (man-pages)
2021-12-02 20:24             ` Alejandro Colomar (man-pages)
2021-12-02 20:31               ` Alejandro Colomar (man-pages) [this message]
2021-12-02 20:36               ` Joseph Myers
2021-11-16  9:30     ` Jonathan Wakely
2021-11-16 17:13       ` [cfe-dev] " Arthur O'Dwyer

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