C++11中std::thread线程实现暂停(挂起)功能-C/C++开发

本文主要介绍了C++11中std::thread线程实现暂停(挂起)功能，文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值，需要的朋友们下面随着小编来一起学习学习吧

一、封装Thread类

我们基于C++11中与平台无关的线程类std::thread，封装Thread类，并提供start()、stop()、pause()、resume()线程控制方法。

为了让线程在暂停期间，处于休眠，不消耗CPU，我们使用C++11提供的锁和条件变量来实现。

std::mutex
std::condition_variable

Thread.h

#ifndef THREAD_H
#define THREAD_H

#include <thread>
#include <atomic>
#include <mutex>
#include <condition_variable>

class Thread
{
public:
    Thread();
    virtual ~Thread();

    enum State
    {
        Stoped,     ///<停止状态，包括从未启动过和启动后被停止
        Running,    ///<运行状态
        Paused      ///<暂停状态
    };

    State state() const;

    void start();
    void stop();
    void pause();
    void resume();

protected:
    virtual void process() = 0;

private:
    void run();

private:
    std::thread* _thread;
    std::mutex _mutex;
    std::condition_variable _condition;
    std::atomic_bool _pauseFlag;   ///<暂停标识
    std::atomic_bool _stopFlag;   ///<停止标识
    State _state;
};

#endif // THREAD_H

Thread.cpp

#include "Thread.h"
#include <iostream>

using namespace std;

Thread::Thread()
    : _thread(nullptr),
      _pauseFlag(false),
      _stopFlag(false),
      _state(Stoped)
{

}

Thread::~Thread()
{
    stop();
}

Thread::State Thread::state() const
{
    return _state;
}

void Thread::start()
{
    if (_thread == nullptr)
    {
        _thread = new thread(&Thread::run, this);
        _pauseFlag = false;
        _stopFlag = false;
        _state = Running;
    }
}

void Thread::stop()
{
    if (_thread != nullptr)
    {
        _pauseFlag = false;
        _stopFlag = true;
        _condition.notify_all();  // Notify one waiting thread, if there is one.
        _thread->join(); // wait for thread finished
        delete _thread;
        _thread = nullptr;
        _state = Stoped;
    }
}

void Thread::pause()
{
    if (_thread != nullptr)
    {
        _pauseFlag = true;
        _state = Paused;
    }
}

void Thread::resume()
{
    if (_thread != nullptr)
    {
        _pauseFlag = false;
        _condition.notify_all();
        _state = Running;
    }
}

void Thread::run()
{
    cout << "enter thread:" << this_thread::get_id() << endl;

    while (!_stopFlag)
    {
        process();
        if (_pauseFlag)
        {
            unique_lock<mutex> locker(_mutex);
            while (_pauseFlag)
            {
                _condition.wait(locker); // Unlock _mutex and wait to be notified
            }
            locker.unlock();
        }
    }
    _pauseFlag = false;
    _stopFlag = false;

    cout << "exit thread:" << this_thread::get_id() << endl;
}

二、测试代码

main.cpp

#include <QCoreApplication>
#include <iostream>
#include "Thread.h"

using namespace std;

void mySleep(int s)
{
    std::this_thread::sleep_for(std::chrono::duration<double>(s));
}

class MyThread : public Thread
{
protected:
    virtual void process() override
    {
        cout << "do my something" << endl;
        mySleep(1);
    }
};

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    MyThread thread;

    cout << "start thread" << endl;
    thread.start();
    cout << "thread state:" << thread.state() << endl;
    mySleep(3);

    cout << "pause thread" << endl;
    thread.pause();
    cout << "thread state:" << thread.state() << endl;
    mySleep(3);

    cout << "resume thread" << endl;
    thread.resume();
    cout << "thread state:" << thread.state() << endl;
    mySleep(3);

    cout << "stop thread" << endl;
    thread.stop();
    cout << "thread state:" << thread.state() << endl;
    mySleep(3);

    return a.exec();
}

运行结果：

IiBzcmM9

到此这篇关于C++11中std::thread线程实现暂停(挂起)功能的文章就介绍到这了,更多相关C++11 std::thread线程暂停内容请搜索编程学习网以前的文章希望大家以后多多支持编程学习网！