Re: gcc fixed size char array initialization bug - known?

From: Al Viro
Date: Thu Aug 02 2007 - 16:09:12 EST


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...
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