Question

Is the following code safe?

class B {
  public:
    int& b;
    B (int& _b) :
      b(_b) {}
};

B* foo() {
  int a;
  return new B(a);
}

Will the reference in the object returned by foo point to nothing (since int a is going out of scope) or does the compile figure this out?

Answer 1

The compiler might warn you, but the newly created object definitely contains a dangling, invalid reference, as the object a stops existing at the end of the scope of foo.