c++11的多线程支持一（线程启动）

支持多线程编程，是c++11的一个新特性。在语言层面编写多线程程序，程序的可移植性得到很大提高。

新的线程库通过std::thread管理线程的执行，启动线程的方式有两种:

1、以一个函数地址为参数，实例化一个std::thread对象;

2、通过一个类的实例构造一个std::thread对象，用于构建std::thread的类必须实现了operator()方法。

一旦传入的函数返回，线程终止。下面以一个实例说明：

#include <iostream>
#include <thread>

void fun()
{
std::cout << "method one: thread start" << std::endl;
std::cout << "method one: thread stop" << std::endl;
}

class run
{
public:
void operator()()
{
std::cout << "method two: thread start" << std::endl;
std::cout << "method two: thread stop" << std::endl;
}
};

int32_t main()
{
// one method of launching thread
std::thread t_1(fun);
std::cout << "method one: start test thread" << std::endl;
t_1.join();
std::cout << "method one: over" << std::endl;

// the other method of launching thread
run r;
//std::thread t_2(r);  // 1. this actually copies the supplied object into the thread.
std::thread t_2(std::ref(r));  // 2. if you want to use the object you supplied, you can do so by wrapping it in std::ref.
std::cout << "method two: start test thread" << std::endl;
t_2.join();
std::cout << "method two: over" << std::endl;
return 0;
}

执行后，这段代码的输出为：

method one: start test thread

method one: thread start

method one: thread stop

method one: over

method two: start test thread

method two: thread start

method two: thread stop

method two: over