C++ Thread taking reference argument failed compile

Question

#include
#include
using namespace std;

void f1(double& ret) {
   ret=5.;
}

int main() {
   double ret=0.;
   thread t1(f1, ret);
         


        

Answer 1

Jonathan's answer is definitive. Time spent studying it would be time well spent.

In the meantime, modifying the code thus will do what you want - namely send a reference into the thread function:

thread t1(f1, std::ref(ret));