What guarantees does D 'const' provide, compared to C++?

[Chris Cain]

On Friday, 17 August 2012 at 01:51:38 UTC, Mehrdad wrote:
> So you're saying casting away a const _pointer_ is undefined, 
> even if the target was originally created as mutable. 
> (Otherwise, the code would certainly be "valid", just like in 
> C++.)
>
>
> Which means you can effectively _never_ cast away constness of 
> a pointer/reference, no matter how certain you are about the 
> target object, right?
>
> If you did, then the code would be invalid, and the compiler 
> could simply format your C: drive instead of modifying the 
> object.
>
> If so, then why is such an undefined cast allowed in the first 
> place?

If you're absolutely 100% completely totally certain that the 
data is mutable (i.e., you have confirmed either through good, 
sound reasoning OR you have some method of seeing exactly where 
it is stored in your RAM and you've checked that the place it is 
stored is writable memory), then __technically__, yes you can 
cast away and modify away. Apparently, according to some, it's 
necessary for low level programming. I'd highly discourage this 
type of behavior because if you're doing something like that I'm 
nearly certain you could come up with a better design, not to 
mention you're missing the point of having something const in the 
first place.

Let's just say I wouldn't use const in a place where I'm itching 
to cast it away. If you're not going to use it to your advantage, 
there's no point.