Hello Steven,
On Mon, 09 Aug 2010 10:24:56 -0400, BCS <[email protected]> wrote:
Hello Steven,
On Sun, 08 Aug 2010 17:56:25 -0400, simendsjo
<[email protected]> 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?
I think you are right re the meaning of those terms but I think what
you thought it to be is more along the lines of what is correct. I
/think/ the situation is that there are things that will work
reliably and things that result in undefined behavior and you're on
your own figuring out what is what.
I'm sort of interpreting what you're saying is:
In some cases, you can cast away const and modify the variable with no
adverse effects, but we can't tell you which cases those are.
Yes and no. Yes, sometimes casting away const and then writing to the pointer
doesn't crash your program (or do anything else) but no that's not what I
was saying. It's still undefined behavior even if it "works". What "your
on your own" with is making sure you don't write to the pointer. Once you
cast, the compiler won't check your work.
Which is kind of like saying "yes, casting away const is allowed, but
only people who wrote the compiler can do it".
-Steve
--
... <IXOYE><
