#include <future>
#include <string>

struct X {
  void foo(int, std::string const&);
  std::string bar(std::string const&);
};

X x;
auto f1 = std::async(&X::foo, &x, 42, "hello");
auto f2 = std::async(&X::bar, x, "goodbye");

struct Y {
  double operator()(double);
};
Y y;
auto f3 = std::async(Y(), 3.141);
auto f4 = std::async(std::ref(y), 2.718);
X baz(X&);
auto f6 = std::async(baz, std::ref(x));
class move_only {
public:
  move_only();
  move_only(move_only&&);
  move_only(move_only const&) = delete;
  move_only& operator         =(move_only&&);
  move_only& operator=(move_only const&) = delete;
  void operator()();
};
auto f5 = std::async(move_only());