c++11 thread類的簡單使用

一個thread對象就表明一個線程執行，當對象建立完成後，線程函數就開始執行，下面這段話是c++11的thread類介紹。

An initialized thread object represents an active thread of execution; Such a thread object is joinable, and has a unique thread id.

A default-constructed (non-initialized) thread object is not joinable, and its thread id is common for all non-joinable threads.

A joinable thread becomes not joinable if moved from, or if either join or detach are called on them.

須要注意的是：當一個線程對象是joinable狀態時，對象在析構前須要使用detach或者jion函數。

如今寫代碼證明這段話，加深c++11 thread類的使用，具體代碼以下：

#include "stdafx.h"
#include <memory>
#include <string>
#include <iostream>
#include <thread>

void pause_thread(int nSleepTime)
{
    //std::cout << "pause for: " << nSleepTime << "\n";
    std::this_thread::sleep_for(std::chrono::seconds(nSleepTime));
}

int main()
{
    //thread1和thread2 是初始化的線程對象，它是joinable狀態而且有惟一的id;
    std::thread thread1(pause_thread, 1);
    std::thread thread2(pause_thread, 2);

    //thread3是未初始化的線程對象，它是非joinable狀態，id不惟一
    std::thread thread3;

    //驗證代碼
    if (thread1.joinable())
    {
        std::cout <<"thread1 is joinable" << std::endl;
    }
    if (thread2.joinable())
    {
        std::cout << "thread2 is joinable" << std::endl;
    }

    if (!thread3.joinable())
    {
        std::cout << "thread3 is not joinable" << std::endl;
    }

    std::cout << "***********分割線*****************\n\n" << std::endl;

    std::cout << "thread1: " << thread1.get_id() << std::endl;
    std::cout << "thread2: " << thread2.get_id() << std::endl;
    std::cout << "thread3: " << thread3.get_id() << std::endl;

    //thread objects that are joinable shall either be joined
    // or detached before they are destroyed.
    thread1.join();
    thread2.detach();

    std::cout << "*************分割線****************\n\n" << std::endl;

    //A joinable thread becomes not joinable if moved from, 
    //or if either join or detach are called on them.

    if (!thread1.joinable())
    {
        std::cout << "thread1 becomes not joinable" << std::endl;
    }
    if (!thread2.joinable())
    {
        std::cout << "thread2 becomes not joinable" << std::endl;
    }

    return 0;
}

運行結果：

參考資料：http://www.cplusplus.com/reference/thread/thread/