Can a C++ class determine whether it’s on the stack or heap?

A hacky way to do it:

struct Detect {
   Detect() {
      int i;
      check(&i);
   }

private:
   void check(int *i) {
      int j;
      if ((i < &j) == ((void*)this < (void*)&j))
         std::cout << "Stack" << std::endl;
      else
         std::cout << "Heap" << std::endl;
   }
};

If the object was created on the stack it must live somewhere in the direction of the outer functions stack variables. The heap usually grows from the other side, so that stack and heap would meet somewhere in the middle.

(There are for sure systems where this wouldn’t work)