1.启动线程

(1)使用对象

“小试牛刀”中thread构造时传入的是函数，还可以传入对象。

#include <thread>
#include <iostream>

void func()
{
    std::cout<<"worker thread ID:"<<std::this_thread::get_id()<<std::endl;
    std::cout<<"Hello Word"<<std::endl;

}

class MyFunc
{
public:
    //重载的函数操作符,对象使用起来就像对象是一个函数一样
    void operator()()//无参数无返回值
    {
        func();
    }
};

int main()
{
    std::cout<<"main thread ID:"<<std::this_thread::get_id()<<std::endl;
    MyFunc myFunc;//需先定义类的对象
    std::thread workerThread(myFunc);
    workerThread.join();
    return 0;
}

(2)使用参数

#include <thread>
#include <iostream>
#include <string>

void func(int i,std::string const &s)
{
    std::cout<<"worker thread ID:"<<std::this_thread::get_id()<<std::endl;
    std::cout<<"Hello Word"<<" "<<s<<" "<<i<<std::endl;
}

int main()
{
    std::cout<<"main thread ID:"<<std::this_thread::get_id()<<std::endl;
    std::string str="at";
    //注意这里第二个参数的写法
    //为何不直接传str:虽然函数func的第二个参数期待传入一个引用，但是std::thread得构造函数
    //并不知晓；构造函数无视函数期待的数据类型，并盲目的拷贝已提供的变量。当线程调用func函数
    //时，传递给函数的参数是str拷贝的引用，而非数据本身的引用。使用std::ref可以解决
    //这个问题，将参数转换成引用的形式。
    std::thread workerThread(func,20161016,std::ref(str));
    workerThread.join();

    return 0;
}

(3)使用move

#include <thread>
#include <iostream>
#include <string>

void func(int i,std::string const &s)
{
    std::cout<<"worker thread ID:"<<std::this_thread::get_id()<<std::endl;
    std::cout<<"Hello Word"<<" "<<s<<" "<<i<<std::endl;
}

void func_other(int i,std::string const &s)
{
    std::cout<<"worker thread ID:"<<std::this_thread::get_id()<<std::endl;
    std::cout<<"C++11"<<" "<<s<<" "<<i<<std::endl;
}

int main()
{
    std::cout<<"main thread ID:"<<std::this_thread::get_id()<<std::endl;
    std::string str="at";
    std::thread workerThread1(func,20161016,std::ref(str));
    std::thread workerThread2=std::move(workerThread1);
    workerThread1=std::thread(func_other,20161016,std::ref(str));
    std::thread workerThread3;
    std::thread workerThread4;
    //此句崩溃，workerThread4并未启动
//  workerThread4.join();
    workerThread3=std::move(workerThread2);
    //此句崩溃，因为workerThread1已经关联一个线程
//  workerThread1=std::move(workerThread3);
    workerThread1.join();
    //此句崩溃，因为workerThread2没有关联一个线程
//  workerThread2.join();
    workerThread3.join();

    return 0;
}

2.后台运行线程

#include <thread>
#include <iostream>
#include <string>
#include <chrono>
#include <assert.h>

void func(int i,std::string const &s)
{
    std::cout<<"worker thread ID:"<<std::this_thread::get_id()<<std::endl;
    std::cout<<"Hello Word"<<" "<<s<<" "<<i<<std::endl;
}

int main()
{
    std::cout<<"main thread ID:"<<std::this_thread::get_id()<<std::endl;
    std::string str="at";
    std::thread workerThread(func,20161016,std::ref(str));
    //使用detach()会让线程在后台运行，也就是说主线程不会等待workerThread结束。如果线程detach(),
    //不可能有std::thread对象能引用它，而且不能再调用该线程的join()方法。
    workerThread.detach();
    //workerThread.joinable()为false
    assert(!workerThread.joinable());
    //延时10秒，否则然函数func函数还未执行，main函数就退出了
    std::this_thread::sleep_for(std::chrono::seconds(10));

    return 0;
}