returning a struct/class, and destructors

If a function returns a class (not as a reference/pointer), are destructors called for the stuff on the stack?

Code:

---

class Bwah{
  public:
      int x;
      Bwah():
        x(0) {}
       
      ~Bwah(){
        cout << "x : " << x << endl;
      }
};

class Assigner{
  public:
      static Bwah boo(){
        Bwah bwah;
        return bwah;
      }
};

int main () {

  {
      Bwah boo = Assigner::boo();
     
      cout << "got here.." << endl;
     
  }
 
}

---

In that example, the destructor only gets called once, after "got here". Where can I read more about this stuff?

You are observing the effects of return value optimisation, where the copy construction is elided in order to avoid what would normally be unnecessary copying.

The short answer is yes.

The reason you are seeing only one object being destroyed is that only one object is being created.

The C++ standard has a rule that explicitly allows a compiler to avoid creating/destroying any temporary object, if the only way to detect existence of such an object is by tracking constructor and destructor calls. Your compiler is presumably taking advantage of that rule (as it allows performance optimisations). Look up topics like "return value optimisation".

Thanks, understood :D