Chrono timer class pass method from class not function

Question

I am trying to make use of the code from tutorialspoint but I am facing a problem when I want to put the function in a class.

#include <functional>
#include <chrono>
#include <future>
#include <cstdio>
class later {
   public:
      template <class callable, class... arguments>
      later(int after, bool async, callable&& f, arguments&&... args){
      std::function<typename std::result_of<callable(arguments...)>::type()> task(std::bind(std::forward<callable>(f), std::forward<arguments>(args)...));
      if (async) {
         std::thread([after, task]() {
            std::this_thread::sleep_for(std::chrono::milliseconds(after));
            task();
         }).detach();
      } else {
         std::this_thread::sleep_for(std::chrono::milliseconds(after));
         task();
      }
   }
};
void test1(void) {
   return;
}

int main() {
   later later_test1(3000, false, &test1);
   later later_test2(1000, false, &test2, 75);
   later later_test3(3000, false, &test2, 101);
}

I would like to put the function test1, whether in the same class or to define a new one.The problem is that code won't compile.

 #include <functional>
    #include <chrono>
    #include <future>
    #include <cstdio>
    class later {
       public:
          template <class callable, class... arguments>
          later(int after, bool async, callable&& f, arguments&&... args){
          std::function<typename std::result_of<callable(arguments...)>::type()> task(std::bind(std::forward<callable>(f), std::forward<arguments>(args)...));
          if (async) {
             std::thread([after, task]() {
                std::this_thread::sleep_for(std::chrono::milliseconds(after));
                task();
             }).detach();
          } else {
             std::this_thread::sleep_for(std::chrono::milliseconds(after));
             task();
          }
       }

    void test1(void) {
       return;
    }
    };
int main() {
   later later_test1(3000, false, &later::test1);
   later later_test2(1000, false, &test2, 75);
   later later_test3(3000, false, &test2, 101);
}    

Answer 1

In your second bit of code, test1 is a non-static member function of later. That means that it needs an object in order to be called.

Make it static:

    static void test1(void) {
       return;
    }