#include <unistd.h>

#include <cstdlib>
#include <iostream>
#include <thread>
#include <memory>

using namespace std;

//---------------------------------------------------------------
// This method mimics the thread doing some actual work.
// It is extremely rare that calling sleep() is the right
// thing to do -- extremely rare.  You should basically never
// do it, as there's some better way in code that actually
// does something.
//---------------------------------------------------------------
void sleep_spin(int delay) {
  for (int i = 0; i < 4; i++) {
    cout << "  sleep_spin(" << delay << ") sleeping..." << endl;
    sleep(delay);
    cout << "  sleep_spin(" << delay << ") done sleeping." << endl;
  }
}

//---------------------------------------------------------------
// New threads start executing here.  They terminate when
// they return from this method.
//---------------------------------------------------------------
void thread_start(int delay) {
  cout << "[child thread] I'm alive!" << endl;
  cout << "[child thread] calling sleep_spin(" << delay << ")" << endl;
  sleep_spin(delay);
  cout << "[child thread] done." << endl;
}

//---------------------------------------------------------------
// The (single) main thread starts executing here.
//---------------------------------------------------------------
int main(int argc, char **argv) {

  // Create a child thread, passing it 1 as its argument.
  cout << "[parent thread] about to create thread..." << endl;
  thread tr = thread(thread_start, 1);

  // wait for that thread to finish
  cout << "[parent thread] joining child thread" << endl;
  tr.join();
  cout << "[parent thread] joined child thread" << endl;

  // do it again, but this time detach from thread
  cout << "[parent thread] creating second thread" << endl;
  thread tr2 = thread(thread_start, 60);
  tr2.detach();

  cout << "[parent thread] done." << endl;

  return EXIT_SUCCESS;
}