c++ - Is it OK to reference an out-of-scope local variable within the same function?

Question

In this code, I reference the local variable b even though it is out of scope. But I do it from within the same function so it's probably still on the stack, right? I ran the program and it worked but I'd like to know if it's guaranteed to work on all implementations.

#include <iostream>

void main()
{
    int* a;
    {
        int b = 5;
        a = &b;
    }
    std::cout << *a;
}

Answer 1

No, that's not guaranteed to work. a is dangling once the inner scope is exited, so any dereference of it results in Undefined Behaviour and nothing whatsoever is guaranteed.