Does using AfxBeginThread() require AfxEndThread()?

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Re: Does using AfxBeginThread() require AfxEndThread()?

Postby Scott McPhillips [MVP] » Thu, 02 Sep 2004 08:11:06 GMT




The call to AfxEndThread is not needed and is considered harmfull.  The 
reason it is not needed is that the return 0 returns to MFC code that 
closes the thread handle.  The reason it is considered harmfull is that 
it never returns.  The thread ceases to exist during the call, and 
therefore the destructors of any objects created on the stack never get 
invoked.

-- 
Scott McPhillips [VC++ MVP]


Re: Does using AfxBeginThread() require AfxEndThread()?

Postby Joseph M. Newcomer » Thu, 02 Sep 2004 23:33:06 GMT

No, and I consider using AfxEndThread to be poor programming practice. A thread should
terminate solely by returning from its top-level function. The place where you showed
AfxEndThread is pointless, because if you look at the code in MFC, you see that it will be
called almost immediately upon return anyway, but I believe that the return should never
be short-circuited.
					joe





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Re: Does using AfxBeginThread() require AfxEndThread()?

Postby Joseph M. Newcomer » Thu, 02 Sep 2004 23:34:29 GMT

You missed the part where I set m_bAutoDelete to FALSE before doing the ResumeThread.
				joe






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Re: Does using AfxBeginThread() require AfxEndThread()?

Postby Joseph M. Newcomer » Thu, 02 Sep 2004 23:35:50 GMT

ust make sure that the m_bAutoDelete is set before the ResumeThread.
joe

On Tue, 31 Aug 2004 15:09:04 -0700, RNEELY < XXXX@XXXXX.COM > wrote:


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Similar Threads:

1.Using AfxBeginThread to create a worker thread...

Code that creates the thread...

m_pListenerThread = (CWinThread*)AfxBeginThread(
(AFX_THREADPROC)ListeningThreadFunction, (LPVOID)this );
ASSERT( m_pListenerThread );


Function that the thread is to run (code stripped out)...


UINT ListeningThreadFunction( LPVOID in_pParam )
{
    while(1)
    {}
}

In both Debug and Release builds, the call to AfxBeginThread hangs
infinitely in thrdcore.cpp, specifically at the function:

BOOL CWinThread::CreateThread(DWORD dwCreateFlags, UINT nStackSize,
LPSECURITY_ATTRIBUTES lpSecurityAttrs)

at the WaitForSingleObject line:

VERIFY(ResumeThread() != (DWORD)-1);
VERIFY(::WaitForSingleObject(startup.hEvent, INFINITE) == WAIT_OBJECT_0);

Now, it has been a long time since I've used a worker thread as opposed to a
GUI thread and I remember that they were trivial to use...

Any suggestions why AfxBeginThread would hang itself?

BTW, the overview of how this all gets called is:

    Application calls an exposed DLL function, the DLL instantiates and
creates a series of classes to use internally, eventually the class which
needs this worker thread to 'listen' gets created.  After the class is
created, an initialization function is called on the class which creates
this thread as you see above.

    Any glaringly stupid things I'm doing/forgetting?

    WTH


2.Using Afxbeginthread

Hi
I have used AfxbeginThread with ThreadProc as first argument. i wantd to ask
what is the use of second type of AfxBeginThread that takes CRunTimeClass *
as parameter..also how to use it..i mean in the first type we just have to
write our code to be executed in the thread with in that Thread function
that is passes as first argument to AfxBeginthread, but what about the other
type..where do we write our code in the second type of this API. could
someone please give me an example coz i cud'nt understand whats written in
msdn..also i didnt find any good example clearly indicating API usage with
CRunTime argument.

Thanx and Regards

Usman Jamil


3.Not understanding 'AfxEndThread'

Hello all,

   I have an app that creates a UI thread, and a worker thread to wait for 
the handle of the UI thread.   But, in the UI thread when I do a 
'AfxEndThread(0,0)'
I get an Assert error:

In the app's view:
void CJunkThreadView::OnButton1() 
{
    pAnyThread = (CAnyThread*)AfxBeginThread(RUNTIME_CLASS(CAnyThread),
	         THREAD_PRIORITY_NORMAL, 0, CREATE_SUSPENDED);
    ASSERT_VALID(pAnyThread);

     //fire off a worker thread to wait for the UI's handle
     if(!(pWrkThd_1 = AfxBeginThread(WrkThread_1,this)))
       return;

    //Let the UI go
     RunUIThread();
}
void CJunkThreadView::RunUIThread()
{
  pAnyThread->m_bAutoDelete = FALSE;
  pAnyThread->ResumeThread();
  Sleep(1000);
  pAnyThread->RunIt();

}
UINT WrkThread_1(LPVOID lParam)
{
    CJunkThreadView* pMe = (CJunkThreadView*)lParam;

    switch(WaitForSingleObject(pMe->pAnyThread->m_hThread,10000))
       {
          case WAIT_OBJECT_0:
		 AfxMessageBox("0");
		 break;
          case WAIT_TIMEOUT:
		 AfxMessageBox("1");
		 break;
       }
   return 1;
}

///---------------------------------------------------------------------------
 'CAnyThread' is the UI thread whose base class is CWinThread and for testing
it has only one function:
void CAnyThread::RunIt()
{
    Sleep(2000);
    AfxMessageBox("Ending Any Thread");

   /*causes assert */
   AfxEndThread(0,0);
}


   I've tried just returning from 'RunIt', which doesn't cause an assert, 
but I
don't get a ' pMe->pAnyThread->m_hThread' handle signalled in the waiting
worker thread.

   Obviously, I don't understand something? Any help appreciated.

TIA,

Ray K.

 

4.Is there any difference between AfxEndThread and TerminateThread ?

Hi,

Is there any difference between AfxEndThread and TerminateThread ? I
know we can use AfxEndThread from within the thread only but any other
difference like, cleaning up or so.. ??

Jigar

5.thread never calls AfxEndThread

Hi,

I have made a simple app with only one button that starts or stop a loop.
This loop is actually a thread.
In my OnInitDialog I create the thread in a suspended state and when I 
click on Start I resume the thread and when it's stop I suspend it.
Here is the code

CTestDlg* pThis;

BOOL CTestDlg::OnInitDialog()
{
...
if (!(m_pThread = AfxBeginThread(
		thScanCarte,
		this,
		THREAD_PRIORITY_NORMAL,
		0,
		CREATE_SUSPENDED,
		NULL)))
	{
		AfxMessageBox(_T("Cannot create thread"));
		return false;
	}
...
}

/* static */
UINT CTestDlg::thScanCarte( LPVOID pParam )
{
	  pThis = (CTestDlg*) pParam;
	  return pThis->thScanCarte();
}

UINT CTestDlg::thScanCarte()
{
	USHORT status;
	CString s;
	bool bFlag = true;

	while(1)
	{
		if (m_bExitThread){
			TRACE(_T("exit thread"));
			AfxEndThread(1);
		}
		
		TRACE(_T("scanthread\n"));
		Sleep(800);
	}
	return 0;
}


void CTestDlg::OnClose()
{
	USHORT status;

	StopThread();
	m_bExitThread = TRUE;
	m_card.Close();

	CDialog::OnClose();
}


The problem is when my app exitI cannot see the trace 'exit thread'.
I think this code never called but why ?
When the app exits I suspend the thread so I suppose this is why
it is never called.

6. AfxEndThread problem

7. Can this be done using C#

8. Can this be done using a Data adapter??



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