Casting away const

[BCS]

Hello Steven,

> On Mon, 09 Aug 2010 10:11:39 -0400, Don <nospam at nospam.com> wrote:
> 
>> Steven Schveighoffer wrote:
>> 
>>> On Sun, 08 Aug 2010 17:56:25 -0400, simendsjo
>>> <simen.endsjo at pandavre.com> wrote:
>>> 
>>>> I'm totally new to the const/immutable thing, so this might be a
>>>> naive  question..
>>>> 
>>>> The spec says:
>>>> "modification after casting away const" => "undefined behavior"
>>> I thought it was "you're on your own", not undefined behavior.  The
>>> former implies there is some "right" way to do this if you know more
>>> about the data than the compiler, the latter implies that there is
>>> no
>>> right way to cast away const.  Am I wrong?
>>> -Steve
>> I think you're wrong. It's OK to cast away const, as long as you
>> don't
>> modify the thing which is supposed to be const.
>> But if you modify it, there's no way the compiler can guarantee that
>> your code will work. Anything could happen.
>
> But then what is the point of casting away const?  If you are not
> going to  modify it, then there is no reason to cast it away.

There are some cases where non-const pointers are used but never modified 
(C api's for instance) cast as always is just a way subvert the type system 
where it gets in your way.

-- 
... <IXOYE><