C++中Qt中使用WINAPI线程的问题

问题描述

我被指派创建一个程序，该程序处理三个 WINAPI 线程并反映进度条中的工作流程.我决定将 Qt Widgets 用于这些目的.我使用 CREATE_SUSPENDED 创建标志创建处于挂起状态的线程，然后在单击按钮时使用 ResumeThread 函数恢复它.当我单击它时，程序因未处理的异常 win32 而崩溃.为什么会发生这种情况?

I was assigned to create a program that handles three WINAPI threads and reflects the workflow of those in progress bars. I decided to use Qt Widgets for these purposes. I create those threads in suspended state, using CREATE_SUSPENDED creation flag, then i resume it with ResumeThread function upon clicking the button. When I click it, the program crashes with an unhandled exception win32. Why could this happen?

我的创建"按钮点击槽

void MainWindow::on_pb_create_clicked()
{
    hThread[0] = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)&ThreadFunc1, NULL, CREATE_SUSPENDED, &thID[0]);
    hThread[1] = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)&ThreadFunc2, NULL, CREATE_SUSPENDED, &thID[1]);
    hThread[2] = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)&ThreadFunc3, NULL, CREATE_SUSPENDED, &thID[2]);
    threadsCreated = true;
}

我的开始"按钮点击槽

void MainWindow::on_pb_start_clicked()
{
    if(threadsCreated)
    {
       for(int i = 0; i = 2; i++)
       {
           ResumeThread(hThread[i]);
       }
    }
    else
    {
        QMessageBox msg;
        msg.setWindowTitle("Error");
        msg.setText("Threads are not created");
        msg.exec();
    }
}

我的线程函数

DWORD WINAPI MainWindow::ThreadFunc1(LPVOID lpParams)
{
    for(int i = 0; i < 100; i++)
    {
        ui->progressBar->setValue(i);
        sleep(500);
    }
    return 0;
}

其他2个线程功能相同，只是进度条不同.

Other 2 thread functions are the same, only using different progress bar.

推荐答案

看来您正在传递一个成员函数指针作为应该执行的函数.请记住，除非静态成员函数，否则您不能在没有执行"函数调用的对象实例的情况下调用成员函数.

It seems you are passing a member function pointer as the function that should be executed.Remember that you can't call a member function without an object instance that "performs" the function call, except for static member functions.

请参阅此线程以获取解决方法:您如何将 CreateThread 用于属于类成员的函数?

See this thread for a workaround: How do you use CreateThread for functions which are class members?

底线是您调用一个静态成员函数，将应该执行某些成员函数调用的对象(在本例中为您的 MainWindow 实例)传递给它，然后该实例执行调用.

Bottom line is you call a static member function, pass it the object that should perform some member function call (your MainWindow instance in this case), then the instance performs the call.

请参阅返回值"下的 CreateThread 的 Microsoft 文档:

See the Microsoft Documentation for CreateThread under "Return value":

请注意，即使 lpStartAddress 指向数据、代码或不可访问，CreateThread 也可能成功.如果线程运行时起始地址无效，则发生异常，线程终止.由于起始地址无效而终止的线程将作为线程进程的错误退出来处理.

https://docs.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-createthread

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