#include <iostream>
#include <string>
#include <thread>
using namespace std;

void func(string m) {
  cout << "&m:" << &m;
  cout << endl;
}

int main() {
  string s = "xxxx";
  cout << "&s:" << &s << endl;
  thread t(func, s);
  t.join();
  return 0;
}

#include <iostream>
#include <string>
#include <thread>
using namespace std;

void func(const string& m) {
  cout << "&m:" << &m;
  cout << endl;
}

int main() {
  string s = "xxxx";
  cout << "&s:" << &s << endl;
  thread t(func, s);
  t.join();
  return 0;
}

#include <iostream>
#include <string>
#include <thread>
using namespace std;

void func(string& m) {
  cout << "&m:" << &m;
  cout << endl;
}

int main() {
  string s = "xxxx";
  cout << "&s:" << &s << endl;
  thread t(func, ref(s));
  t.join();
  return 0;
}

#include <iostream>
#include <string>
#include <thread>
using namespace std;

void func(string* m) {
  cout << "m:" << m;
  cout << endl;
  *m = "yyy";
}

int main() {
  string* s = new string("xxx");
  cout << "s:" << s << endl;
  thread t(func, s);
  t.join();
  cout << "s:" << *s << endl;
  return 0;
}