c++11 - Passing by reference to std::thread c++0x in VS2012 -

void threadfn(int& i) {     cout<<"hi thread "<<i<<endl; } int x = 0; void createthreads(vector<thread>& workers) {     for(int = 0; i< 10; i++)     {         workers.push_back(thread(&threadfn, x));     } } 

i expecting compilation error in thread creation (workers.push_back(thread(&threadfn, x));) since x should passed ref. though right syntax should've been:

workers.push_back(thread(&threadfn, std::ref(x))); 

of course, code compiles fine , behaves properly. using vc11. idea why isn't being flagged?

this vc11 bug, thread object makes internal copies of arguments (as should) doesn't forward them threadfn function correctly, happens reference binds thread object's internal int member.

gcc's std::thread used have similar bug because used std::bind implement it, replaced use of std::bind different implementation detail forwards captured arguments function value.