如何在类函数内部创建线程? [英] How to create a thread inside a class function?

问题描述

我对C ++很陌生.

I am very new to C++.

我有一个类，我想在一个类的函数内创建一个线程.该线程(函数)将调用并访问类的函数和变量. 在开始时，我尝试使用Pthread，但仅在类外部工作，如果我想访问类函数/变量，则会遇到范围错误. 我看了一下Boost/thread，但这是不理想的，因为我不想将任何其他库添加到我的文件中(由于其他原因).

I have a class, and I want to create a thread inside a class's function. And that thread(function) will call and access the class function and variable as well. At the beginning I tried to use Pthread, but only work outside a class, if I want to access the class function/variable I got an out of scope error. I take a look at Boost/thread but it is not desirable because of I don't want to add any other library to my files(for other reason).

我做了一些研究，找不到任何有用的答案. 请举一些例子来指导我.非常感谢！

I did some research and cannot find any useful answers. Please give some examples to guide me. Thank you so much!

尝试使用pthread(但是我不知道如何处理我上面提到的情况):

Attempt using pthread(but I dont know how to deal with the situation I stated above):

#include <pthread.h>

void* print(void* data)
{
    std::cout << *((std::string*)data) << "\n";
    return NULL; // We could return data here if we wanted to
}

int main()
{
    std::string message = "Hello, pthreads!";
    pthread_t threadHandle;
    pthread_create(&threadHandle, NULL, &print, &message);
    // Wait for the thread to finish, then exit
    pthread_join(threadHandle, NULL);
    return 0;
}

推荐答案

您可以将静态成员函数传递给pthread，并将对象的实例作为其参数.这个成语是这样的:

You can pass a static member function to a pthread, and an instance of an object as its argument. The idiom goes something like this:

class Parallel
{
private:
    pthread_t thread;

    static void * staticEntryPoint(void * c);
    void entryPoint();

public:
    void start();
};

void Parallel::start()
{
    pthread_create(&thread, NULL, Parallel::staticEntryPoint, this);
}

void * Parallel::staticEntryPoint(void * c)
{
    ((Parallel *) c)->entryPoint();
    return NULL;
}

void Parallel::entryPoint()
{
    // thread body
}

这是一个pthread示例.您可能可以轻松地将其改编为使用std :: thread.

This is a pthread example. You can probably adapt it to use a std::thread without much difficulty.

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