fork(2) download

#include <functional>
#include <vector>
 
int main()
{
	auto x = std::cref(&std::vector<int>::empty);
}

prog.cpp: In function ‘int main()’:
prog.cpp:6:45: error: use of deleted function ‘void std::cref(const _Tp&&) [with _Tp = bool (std::vector<int>::*)()const noexcept (true)]’
  auto x = std::cref(&std::vector<int>::empty);
                                             ^
In file included from prog.cpp:1:0:
/usr/include/c++/4.8/functional:488:10: error: declared here
     void cref(const _Tp&&) = delete;
          ^
prog.cpp:6:45: error: ‘void x’ has incomplete type
  auto x = std::cref(&std::vector<int>::empty);
                                             ^

Standard output is empty