C++語法小記---自己實現Thread類

自己實現Thread類

• 在C++的類中，普通成員函數不能作為pthread_create的線程函數，如果要作為pthread_create中的線程函數，必須是static !

• 參考：https://blog.csdn.net/ksn13/article/details/40538083

//方式1：使用類的static函數做轉換，配合this指針
class Thread
{
private:
    pthread_t id;
    
    static void * start_thread(void *arg)
    {
        Thread* thread = (Thread*)arg;
        thread->run();
    }

public:
    
    virtual void run()
    {
        cout << "success" <<endl;
    }
    
    virtual void start()
    {
        pthread_create(&id, NULL, start_thread, (void *)this);//傳入this指針是關鍵
    }
}; 

class MyThead: public Thread
{
public:
    virtual void run()
    {
        cout << "MyThead::run()" << endl;
    }
};


int main()
{
    MyThead t;
    t.start();
    
    sleep(2);
    
    return 0;
}

 

//方式2：直接使用強制類型轉換，因為this->xxx() 本質上等同於 xxx(this)
//方式2比當時1更安全，因為沒有使用static
class Thread
{
private:
    pthread_t id;
    
    void* threadFunc(void* arg)
    {
        this->run();
    }

public:
    
    typedef void* (*FUNC)(void*);
    
    virtual void run()
    {
        cout << "success" <<endl;
    }
    
    virtual void start()
    {
        FUNC callback = (FUNC)&Thread::threadFunc;
        pthread_create(&id, NULL, callback, this); //此處傳入this是必須的，且在callback中arg不可用，因為為NULL
    }
}; 

class MyThead1: public Thread
{
public:
    virtual void run()
    {
        sleep(1);
        cout << "MyThead1::run()" << endl;
        
    }
};

class MyThead2: public Thread
{
public:
    virtual void run()
    {
        cout << "MyThead2::run()" << endl;
    }
};

int main()
{
    MyThead1 t1;
    t1.start();
    
    MyThead2 t2;
    t2.start();
    
    sleep(2);
    
    return 0;
}