如何停止运行永久阻塞循环的QThread? [英] How to Stop a QThread That Runs a Blocking Forever Loop?

问题描述

我已经尝试了一些粗糙的代码:

I have some rough code that I've been experimenting with:

someserver.cpp(GUI)

someserver.cpp (a GUI)

#include "server.h"
#include "ui_server.h"

Server::Server(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::Server)
{
    ui->setupUi(this);
}

Server::~Server()
{
    delete ui;
}

void Server::onBtnStartClicked()
{
    QThread worker; 
    worker.start(); // Start worker thread that goes into an infinite loop with a blocking call
}

void Server::onBtnExitClicked()
{
    // How do I cleanly stop worker from running?
    QApplication::quit();
}

worker.cpp

worker.cpp

#include "worker.h"

Worker::Worker(QObject *parent) :
    QThread(parent)
{
}

void Worker::run()
{
    for (;;)
    {
        // a blocking IO call here like pipe, or msgrcv
        // process data received
    }
}

由于工作线程以阻塞的IO调用在永久循环中运行，我将如何构造它，以便在GUI线程中按下停止"按钮时，工作线程会干净地停止?

Since the worker thread runs in a forever loop with a blocking IO call, how will I be able to structure this so that when the Stop button is pressed in the GUI thread, the worker thread is stopped cleanly?

推荐答案

您当然可以在每次迭代检查的Worker::run()中的for循环中放入一个布尔值，该值在== true处中断，由gui Stop设置.按钮.当然，这在执行被阻止时不会退出线程.

You could of course put a boolean value within the for loop in Worker::run() checked every iteration, which breaks on ==true and is set by the gui Stop button. Of course, this won't quit the thread while execution is blocked.

可能更好的方法是摆脱for循环，并使用Qt的信号和插槽来设置回调函数，该回调函数连接到类似于QIODevice::readyRead()的信号.仅当套接字/管道中有可用信息时，才调用它们.在任何其他时间，您都可以使用QThread::exit()退出线程.您还需要在某个时刻调用QThread::exec()，以使事件循环继续进行.

Probably better is to get rid of the for loop and use Qt's signals and slots to setup a callback function, connected to a signal like QIODevice::readyRead(). These will be called only when there is information available in the socket/pipe whatever. Any other time you'll be able to quit the thread with QThread::exit(). You'll need to call QThread::exec() at some point as well to get the event loop going.

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