linux-kernel - Re: gcc fixed size char array initialization bug

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Message-ID: <Pine.LNX.4.64.0708022157310.9319@fbirervta.pbzchgretzou.qr>
Date:	Thu, 2 Aug 2007 21:59:55 +0200 (CEST)
From:	Jan Engelhardt <jengelh@...putergmbh.de>
To:	Guennadi Liakhovetski <g.liakhovetski@....de>
cc:	linux-kernel@...r.kernel.org
Subject: Re: gcc fixed size char array initialization bug - known?

On Aug 2 2007 21:55, Guennadi Liakhovetski wrote:
>Hi
>
>I've run across the following gcc "feature":
>
>	char c[4] = "01234";
>
>gcc emits a nice warning
>
>warning: initializer-string for array of chars is too long
>
>But do a
>
>	char c[4] = "0123";
>
>and - a wonder - no warning. 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...

What does this have to do with the kernel? The string "0123" is
generally _five_ characters long, so c[4] is not enough.
Or use strncpy.

	Jan
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