When should RVO kick-in?

Question

From the following code, If RVO has happened, I expect to see the 2 addresses pointing to the same location, however this is not the case (my compiler is MS VC9.0)

Answer 1

You seem to misunderstand RVO, try this example (actually NRVO):

std::string foo(const char* const s)
{
    std::string out(s);
    std::cout << "address: " << (void*)(&out) << std::endl;
    return out;
}

int main()
{
   std::string s = foo("abc");
   std::cout << "address: " << (void*)(&s) << std::endl;
}