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SubjectRe: Patch to remove undefined C code
On Tue, 17 Oct 2000, Richard Guenther wrote:

> On Mon, 16 Oct 2000, Bernd Schmidt wrote:
>
> > I've been playing with some gcc patches to detect code with undefined
> > behaviour of the i = i++ variety. The patch below fixes all places in
> > the kernel that I could find. Note that in some cases, it wasn't
> > entirely clear what the code intended, so I had to guess.
> >
> > I haven't tested this patch at all other than to make sure it compiles.
>
> The following one is wrong, tho - should be rather
> str[i] = dn[i]; i++;

Nope. (Well, at least you need to add extra braces.) The comma is a
sequence point.

> > diff -x log.build -x .* -dru linux-2.4/drivers/isdn/sc/debug.c linux-2.4-fixed/drivers/isdn/sc/debug.c
> > --- linux-2.4/drivers/isdn/sc/debug.c Thu Apr 2 01:21:04 1998
> > +++ linux-2.4-fixed/drivers/isdn/sc/debug.c Mon Oct 16 14:53:49 2000
> > @@ -70,6 +70,6 @@
> > int i = 0;
> >
> > while(dn[i] != ',')
> > - str[i] = dn[i++];
> > + str[i] = dn[i], i++;
> > str[i] = 0x0;
> > }


Bernd

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