Re: Why is the kfree() argument const?
From: Jakob Oestergaard
Date: Fri Jan 18 2008 - 09:53:59 EST
On Fri, Jan 18, 2008 at 02:31:16PM +0100, Björn Steinbrink wrote:
...
>
> Do you see anything that casts the const away? No? Me neither. Still,
> the memory that p points to was changed, because there was another
> pointer and that was not const.
*another* being key here.
>
> > *That* is the purpose of const pointers.
>
> The only thing that const can tell you is that you should not modify the
> value _yourself_, using that pointer _directly_.
Which is pretty damn useful.
Think about it. Don't you ever use const? Is it ever only in the way?
...
{snip long explanation about how one can avoid the benefits of const, without
using casts}
...
> If you want to restrict the set of pointers that can be invalidated by
> an other pointer, you'll have to use something else because const does
> not talk about invalidating aliasing pointers.
Precisely, so why are we discussing this?
I claim that const is useful. You claim that it can't solve all the worlds
problems. I agree with that, but I maintain it is still useful.
But, in order for it to be useful, it requires that people do not circumvent it
in the wrong places (such as kfree).
--
/ jakob
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