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From: Al Viro <viro@ftp.linux.org.uk>
To: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: gcc fixed size char array initialization bug - known?
Date: Thu, 2 Aug 2007 21:08:56 +0100	[thread overview]
Message-ID: <20070802200856.GO21089@ftp.linux.org.uk> (raw)
In-Reply-To: <Pine.LNX.4.60.0708022141420.6774@poirot.grange>

On Thu, Aug 02, 2007 at 09:55:51PM +0200, Guennadi Liakhovetski wrote:
> But do a
> 
> 	char c[4] = "0123";
> 
> and - a wonder - no warning.

And this is a correct behaviour.  You get a valid initialier for array;
see 6.7.8[14] for details.  Moreover, that kind of code is often
quite deliberate.

>No warning with gcc 3.3.2, 3.3.5, 3.4.5, 
> 4.1.2. I was told 4.2.x does produce a warning. Now do a
> 
> 	struct {
> 		char c[4];
> 		int i;
> 	} t;
> 	t.i = 0x12345678;
> 	strcpy(t.c, c);
> 
> and t.i is silently corrupted. Just wanted to ask if this is known, 
> really...

strcpy() from array that doesn't contain 0 is an undefined behaviour,
nothing new about that...

  parent reply	other threads:[~2007-08-02 20:09 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-08-02 19:55 gcc fixed size char array initialization bug - known? Guennadi Liakhovetski
2007-08-02 19:59 ` Jan Engelhardt
2007-08-02 20:03   ` Jesper Juhl
2007-08-02 20:10     ` Al Viro
2007-08-02 20:12       ` Jesper Juhl
2007-08-02 20:15     ` Guennadi Liakhovetski
2007-08-03  3:17   ` Satyam Sharma
2007-08-03  3:40     ` WANG Cong
2007-08-03  7:32       ` Bernd Petrovitsch
2007-08-02 20:08 ` Al Viro [this message]
2007-08-02 20:21   ` Guennadi Liakhovetski
2007-08-02 20:26   ` Guennadi Liakhovetski
2007-08-02 21:09     ` Al Viro
2007-08-02 21:26       ` Guennadi Liakhovetski
2007-08-02 20:18 ` Jan Engelhardt
2007-08-02 21:06 ` Andi Kleen
2007-08-02 20:36   ` Guennadi Liakhovetski
2007-08-02 22:15     ` Stefan Richter
2007-08-02 22:36       ` Guennadi Liakhovetski
2007-08-02 22:42         ` (off-topic) " Stefan Richter
2007-08-02 22:54         ` Randy Dunlap
2007-08-02 23:03           ` Al Viro
2007-08-02 23:26           ` Guennadi Liakhovetski
2007-08-02 23:34             ` Rene Herman
2007-08-03  5:00             ` Carlo Florendo
2007-08-02 23:02         ` Al Viro
2007-08-03  4:57         ` Carlo Florendo
2007-08-02 22:31     ` Stefan Richter
2007-08-02 22:51       ` Guennadi Liakhovetski
2007-08-02 23:09         ` Al Viro
2007-08-02 23:27           ` Stefan Richter
2007-08-02 23:30           ` Guennadi Liakhovetski
2007-08-03  7:56             ` Jan Engelhardt
2007-08-03 14:04           ` Alexander van Heukelum
2007-08-02 23:42 ` Jakub Jelinek
2007-08-03 15:16   ` Stefan Richter
     [not found] <fa.LxMYkBaN628VuktB9CFi9SC3LTA@ifi.uio.no>
     [not found] ` <fa.6wYNfcIjXc+jXzdUGE5gFFOal1g@ifi.uio.no>
     [not found]   ` <fa.cjPWb5ZShF43DhggNXkMKMadPYY@ifi.uio.no>
2007-08-02 21:42     ` Robert Hancock

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