Messages in this thread | | | Date | Fri, 15 Apr 2011 19:28:24 +0300 | From | Phil Carmody <> | Subject | Re: [PATCH 0/1] mm: make read-only accessors take const pointer parameters |
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On 15/04/11 18:12 +0200, ext Michal Nazarewicz wrote: > On Fri, 15 Apr 2011 17:59:16 +0200, Phil Carmody wrote: >> I'm just glad this wasn't an insta-nack, as I am quite a fan of >> consts, and hopefully something can be worked out. > > I feel you man. Unfortunately, I think that const, since it's an > after-thought, is not very usable in C. > > For instance, as you've pointed in your patch, the "_ro" suffix > is sort of dumb, but without it compound_head would have to take > const and return non-const (like strchr() does) which is kinda > stupid as well. > > What's more, because of lack of encapsulation, “const struct page” > only means that the object is const but thighs it points to aren't. > As such, const does not really play that well with structs anyway.
I'm very glad you've mentioned that point, I forgot to. I've taken the view that in the absense of inside knowledge, const should be inherited down all pointers. So not only will I not change you, but I will not change anything you point to. No hidden side effects of any kind. That reduces where it can be used, but is a much stronger statement when it can be made.
> const is, in my opinion, one of those things C++ actually got > right (or close to right).
I shouldn't be seen to agree with you on that, lest any fellow Nokians notice that I've implied something positive about C++ after my rant on our core chat channel a few days back. ;-)
Cheers, Phil -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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