If I'm not totally confused, that second line will do two things. It will call ~std::string() on *str, then it will assign the new string "something" to *str.
Is there a way to opt out of that ~? Say I really need, never mind if it's a good idea I just need, to store a str in a buffer created outside C++. When I'm done with it I'll call the destructor by hand. How do I initially populate it?
