C / C++ / MFC

1-Apr-10 11:06

I have read through www.flounder.com Asynchronous Process Notification/Worker Thread and Arjay thread articles but I can't figure out how to get the two work together

From Asynchronous Process Notification, I understand to use Afxbeginthread to create a thread to wait for the process to end and post a message.
From Worker Thread and Arjay thread articles, I understand that I can use SuspendThread() and ResumeThread().

void CProcessManagerDlg::OnBnRun()
{
       ptrThread = AfxBeginThread(WaitThread, this, THREAD_PRIORITY_NORMAL,0,CREATE_SUSPENDED);
	ptrThread->m_bAutoDelete = FALSE;
	ptrThread->ResumeThread();
}

void CProcessManagerDlg::OnPause()
{
      ptrThread->SuspendThread(); 
}

UINT WaitThread(void *pParam)
{
   CProcessManagerDlg* pThis= (CProcessManagerDlg*)pParam;	
   HANDLE hProcess = Launch(_T("notepad"));  // Or cmd.exe
  ::WaitForSingleObject(hProcess, INFINITE);
   pThis->PostMessage(UWM_DONE, 0, (LPARAM)hProcess);
}

Press Pause wouldn't do anything. I am guessing WaitForSingleObject is preventing the thread from receiving suspend or resume(which would explain why TerminateThread and PostMessage(WM_QUIT) do not work either). So how would I go about suspending a thread that needs to waitforsingleobject on external process?

Richard Andrew x641-Apr-10 11:13

1-Apr-10 11:13

Why do you need to suspend the thread if it's already waiting for the external process?

Orion Star2-Apr-10 4:12

2-Apr-10 4:12

I want the ability to pause/resume the external process.

Richard Andrew x642-Apr-10 4:53

2-Apr-10 4:53

The thread that launches the process is not the thread inside that process. Each process has its own threads.

If you want to pause the external process, you'll need to use the information in this article:

http://msdn.microsoft.com/en-us/library/ms686701(VS.85).aspx[^]

Specifically, see Traversing the thread list.

Orion Star2-Apr-10 5:12

2-Apr-10 5:12

Ah so I can't use the thread that spawn the process to pause it. This is going to be a lot more complicated Dead | X|

Thanks for the link I am looking into it. I don't suppose there is an article with demo on here or CodeGuru for me to fiddle with it.

Richard Andrew x642-Apr-10 5:15

2-Apr-10 5:15

There very well might be an article here.

The idea is that you enumerate all the processes until you find the one you just launched, then enumerate all the threads in the process and pause each one.

Richard Andrew x642-Apr-10 5:35

Re: Suspend ShellExcuteExd

2-Apr-10 5:35

I forgot to mention that if you want to start the external process in a suspended state, you can call CreateProcess() with a special flag called CREATE_SUSPENDED, and the process will be loaded, but will not run until you resume each of its threads.

Orion Star2-Apr-10 9:53

Re: Suspend ShellExcuteExd

2-Apr-10 9:53

I have to look into that. With Pause and Resume I noticed how much I could have used PROCESS_INFORMATION. I could have skipped thread list traverse with SuspendThread(pi.dwThreadId),if I am not mistaken

Richard Andrew x642-Apr-10 9:56

Re: Suspend ShellExcuteExd

2-Apr-10 9:56

Yes, you could have. But if the remote process spawns any new threads, you would still have to enumerate them to see what they are.

Orion Star2-Apr-10 10:09

2-Apr-10 10:09

Thanks again. Thumbs Up | :thumbsup:

You have no idea how long I have been racking over my brain over this problem. WTF | :WTF:

Orion Star2-Apr-10 9:45

2-Apr-10 9:45

Thanks it worked

Combine Traversing the thread with this
http://www.woodmann.com/forum/showthread.php?t=12353[^] I was able to pause and resume.

Adam Roderick J1-Apr-10 19:58

Adam Roderick J

1-Apr-10 19:58

Did u used ShellExecute to create the process?

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Orion Star2-Apr-10 4:13

2-Apr-10 4:13

Sorry if I wasn't clear my Launch() = ShellExecuteEx

Adam Roderick J2-Apr-10 5:11

Adam Roderick J

2-Apr-10 5:11

Can you show the code inside Launch()?
Well i prefer to use CreateProcess. Smile | :)

Величие не Бога может быть недооценена.

Orion Star2-Apr-10 9:35