On Fri, Dec 18, 2009 at 6:19 PM, Emil Dotchevski <emildotchevski@gmail.com> wrote:
On Fri, Dec 18, 2009 at 11:07 AM, Felipe Magno de Almeida <felipe.m.almeida@gmail.com> wrote:
[snip]
It is not portable if we dereference it, which optional does.
I am going off of what Giovanni said earlier in this thread about how optional works, which seems to contradict your statement above.
I re-read what Giovanni said. And it seems to me it still dereferences it. Indirectly, but does it. If a perfectly valid implementation negates the bits in a a pointer for a reintepret_cast and you pass it to placement new it will probably fail. [snip]
Casting to a pointer of unrelated type doesn't suite static_cast, reinterpret_cast is a better choice.
I don't understand why. How is reinterpret_cast better than static_cast?
In this case reinterpret_cast is a better choice because even with static_cast, the cast is just as unsafe, but may appear safer because static_cast is perceived as safer than reinterpret_cast.
It is not just as unsafe. static_cast is guaranteed to do what is needed. reinterpret_cast doesn't. It is implementation-defined and can do whatever it wants, as long as a reinterpret_cast back results in the same pointer as before.
You don't want to make it harder for the programmer to see that the operation is potentially dangerous, do you?
It is if you do reintepret_cast. Not if you do static_cast.
Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode
[snip] -- Felipe Magno de Almeida