c++ - cannot able to create enum type as atomic -

#include <iostream> #include <atomic> using namespace std;     typedef enum day{sun =0, mon, tue}day;      int main() {     atomic<day> a(sun);     cout<<a<<endl;     return 0; } 

the above code try create enum variable atomic type. getting following error.

undefined reference std::atomic<day>::operator day() const 

does atomic have no support enum type? or mistake in syntax? using g++ compiler running on 32 bit ubuntu 12.0.4 machine. thank you.

i've compiled same code online compiler supports c++11 & c++14. didn't issues.

atomic isn't available before c++11 standards.

for reference: http://ideone.com/fork/pe4gvt