std::make_tuple doesn't make references

Question

I've been experimenting with std::tuple in combination with references:

#include <iostream>
#include <tuple>

int main() {
  int a,b;
  std::tuple<int&,int&> test(a,b);
  std::get<0>(test) = 1;
  std::get<1>(test) = 2;
  std::cout << a << ":" << b << std::endl;

  // doesn't make ref, not expected
  auto test2 = std::make_tuple(a,b);
  std::get<0>(test2) = -1;
  std::get<1>(test2) = -2;
  std::cout << a << ":" << b << std::endl;

  int &ar=a;
  int &br=b;
  // why does this not make a tuple of int& references? can we force it to notice?
  auto test3 = std::make_tuple(ar,br);
  std::get<0>(test3) = -1;
  std::get<1>(test3) = -2;
  std::cout << a << ":" << b << std::endl;
}

Of the three examples here the first two work as expected. The third one however does not. I was expecting the auto type (test3) to be the same as the type of test (i.e. std::tuple<int&,int&>).

It seems that std::make_tuple can't automatically make tuples of references. Why not? What can I do to make this the case, other than explicitly constructing something of that type myself?

(Compiler was g++ 4.4.5, using 4.5 doesn't change it)

Answer 1

Try forward_as_tuple:

auto test3 = std::forward_as_tuple(ar,br);