How to create timer using C++11?

Here we will see how to make timer using C++. Here we are creating one class called later. This class has following properties.

• int (milliseconds to wait until to run code)
• bool (If this is true, it returns instantly, and run the code after specified time on another thread)
• The variable arguments (exactly we want to feed to std::bind)

We can change the chrono::milliseconds to nanoseconds or microseconds etc. to change the precision.

Example Code

#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;
}
void test2(int a) {
   printf("result of test 2: %d\n", a);
   return;
}
int main() {
   later later_test1(3000, false, &test1);
   later later_test2(1000, false, &test2, 75);
   later later_test3(3000, false, &test2, 101);
}

Output

$ g++ test.cpp -lpthread
$ ./a.out
result of test 2: 75
result of test 2: 101
$

first result after 4 seconds. The second result after three seconds from the first one