1.future线程通信

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

 //全局通信变量
 promise<string> val;

 void main()
 {
     auto fun1 = []()
     {
         //一直等待,获取全局变量的值
         future<string> fu = val.get_future();
         cout << "Waitting" << endl;
         cout <<"获取线程消息" << fu.get() << endl;
     };

     auto fun2 = []()
     {
         system("pause");
         //val.set_value("hello");
         string str1;
         cin >> str1;
         val.set_value(str1);
         system("pause");
     };

     thread t1(fun1);
     thread t2(fun2);

     t1.join();
     t2.join();
     system("pause");
 }