返回WaitForMultipleObject() [英] return of WaitForMultipleObject()

问题描述

在基于MFC对话框的应用程序中，有一个父线程，并且在这个父线程中，我有多个(不是固定数量的)子线程.
子线程指针被声明为CWinThread *Thread[2];，并在类似以下的循环中使用:

In my MFC dialog-based application there is one parent thread and inside this parent thread I am having multiple (not a fixed number) of child threads.
The child thread pointers are declared as CWinThread *Thread[2]; and used in a loop like:

while(codn==true)
{
  Thread[0]=AfxBeginThread(Thread1,LPVOID(NULL));
  Thread[1]=AfxBeginThread(Thread2,LPVOID(NULL));
}

上面的while循环没有迭代.时代.
我正在使用WaitForMultipleObject()等待所有子线程发出信号，然后终止父线程.
WaitForMultipleObjects的返回始终为-1.


子线程变量会被覆盖吗?
是否还有其他方法可以分配不固定的子线程变量，这些变量将取决于运行时...

请帮忙！

The above while loop iterates no. of times.
I m using WaitForMultipleObject() to wait for all child thread to signal before the termination of the parent thread.
The return of WaitForMultipleObjects is always -1.


The child thread variables gets overwritten?
Is there any other method to assign the child thread variables that are not fixed and will depends on runtime...

Please help! How can I wait for all the child threads to complete their tasks before terminating the parent thread?

推荐答案

AfxBeginThread返回一个CWinThread对象，该对象在线程过程返回时删除自身.

来自MSDN:
dwCreateFlags
指定一个控制线程创建的附加标志.该标志可以包含两个值之一:

CREATE_SUSPENDED以挂起计数1启动线程.如果要在线程开始运行之前初始化CWinThread对象的任何成员数据(例如m_bAutoDelete或派生类的任何成员)，请使用CREATE_SUSPENDED.初始化完成后，使用CWinThread :: ResumeThread启动线程运行.在调用CWinThread :: ResumeThread之前，线程不会执行.

AfxBeginThread returns a CWinThread object, which deletes itself when the thread procedure returns.

From MSDN:
dwCreateFlags
Specifies an additional flag that controls the creation of the thread. This flag can contain one of two values:

CREATE_SUSPENDED Start the thread with a suspend count of one. Use CREATE_SUSPENDED if you want to initialize any member data of the CWinThread object, such as m_bAutoDelete or any members of your derived class, before the thread starts running. Once your initialization is complete, use CWinThread::ResumeThread to start the thread running. The thread will not execute until CWinThread::ResumeThread is called.

上面的循环会覆盖您的vars，
因此您将无法引用创建的线程...

您如何确切使用功能WaitForMultipleObjects(..)? :)

The loop above does overwrite your vars,
so you will not can to reference the created threads...

How do you use the function WaitForMultipleObjects(..) exactly ? :)

sksksksksksksks写道:

sksksksksksksks wrote:

是否还有其他方法可以分配不固定的子线程变量，这些变量将取决于运行时...

Is there any other method to assign the child thread variables that are not fixed and will depends on runtime...

您需要多少个线程?
如果它们只有两个，则不需要循环:)

假设您的var有效:

How many threads do you need ?
If they are two only then you do not need the loop :)

Assumed your vars are valid:

void CYourDialog::EndWorkers()
{
  /*volatile bool*/ m_bExitThreads = true; // signal the threads
                                           // about the exiting
  if (m_Thread[0] && m_Thread[1]) {
    HANDLE hThreads[2] = {
      m_Thread[0]->m_hThread,
      m_Thread[1]->m_hThread
    };
 
    WaitForMultipleObjects(2,
                           hThreads,
                           TRUE,
                           INFINITE);
 
    m_Thread[0] = m_Thread[1] = NULL;
  }
}

实际上不考虑线程的子父关系. :)
主线程和辅助线程是一个更好的描述.
好吧，WaitForMultipleObjects本身就足够了，但是您已经提到了线程数，以便等待所有线程退出:)
但是只需遍历以下链接中提到的此代码段即可，该示例代码等待所有线程终止 ^ ]

Actually dont consider child parent relation for a thread. :)
Main Thread and worker thread is a better description.
Well WaitForMultipleObjects itself it enough but you have mention the Thread count so that waits for the all threads to exit :)
But just go through this code snippet mentioned in below link, a sample code that waits for the all thread to terminate [^]

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