C++ std::function<>におけるmemory allocationの疑問

from_lambda_to_std_function.cpp

#include <cassert>
#include <iostream>
#include <functional>

std::function<int (int)> make_g(int x)
{
  std::cout << "Stack  var: " << &x << std::endl;
  return [x] (int y) {
    std::cout << "Lambda var: " << &x << std::endl;
    return x + y;
  };
}

int main(int argc, char ** argv)
{
  int x = (argc <= 1) ? 1 : std::atoi(argv[1]);
  std::function<int (int)> g = make_g(x);
  assert(x+5 == g(5));
  auto h = [x](int y) {
    std::cout << "unreturned var : " << &x << "\n" ;
    return x + y;
  };
  assert(x+5 == h(5));
  std::cout << "heap   var: " << &std::vector<int>(5)[0] << "\n";
}