线程异步和通信（promise和future）

#include <thread>
#include <iostream>
#include <future>
#include <string>
using namespace std;void TestFuture(promise<string> p)//线程函数
{cout << "begin TestFuture" << endl;this_thread::sleep_for(3s);cout << "begin set value" << endl;p.set_value("TestFuture value");this_thread::sleep_for(3s);cout << "end TestFuture" << endl;
}int main(int argc, char* argv[])
{//异步传输变量存储promise<string> p;//用来获取线程异步值获取auto future = p.get_future();auto th = thread(TestFuture, move(p));//启动线程cout << "begin future.get()" << endl;cout <<  "future get() = " << future.get() << endl;cout << "end future.get()" << endl;th.join();//等待线程的退出getchar();return 0;
}