c++多线程使用

1.c++ thread

点击查看代码

#include <iostream>
#include <thread>
void M_threadFun()
{
    std::cout<<"now thread begin running"<<std::endl;
    for(int i=0;i<10;++i)
    {
        std::this_thread::sleep_for(std::chrono::milliseconds(100));
    }
    std::cout<<"now thread should quit"<<std::endl;
}
int main()
{
    //this is main thread
    std::cout<<"this is in main"<<std::endl;
    auto th  = new std::thread(M_threadFun);
    th->join();
    std::cout<<"now in main"<<std::endl;
}

2.#pragma omp parallel关键字
该关键字也可以实现多线程的功能，但是需要注意：#pragma omp parallel关键字创建多线程必须在编译时加上-fopenmp选项

点击查看代码

（1）#pragma omp parallel for

         for()

（2）#pragma omp parallel

        {//注意：大括号必须要另起一行

         #pragma omp for

          for()

        }