26.多线程join detach

 #include <iostream>
 #include <thread>
 #include <array>
 #include <Windows.h>
 using namespace std;

 void show()
 {
     MessageBoxA(, "", "", );
 }

 void main()
 {
     //获取CPU核心的个数
     auto n = thread::hardware_concurrency();
     cout << "CPU核心个数:" << n << endl;
     array<thread, > threads{thread(show), thread(show), thread(show)};

     for (int i=;i<;i++)
     {
         //使用join后主线程等待执行完之后才结束
         //threads[i].join();
         //脱离主线程,主线程结束不报错,自动退出
         threads[i].detach();
     }

     Sleep();
 }