Re: CWinThread, CFrameWnd and memory leak???

From:

"Ian Semmel" <anyone@rocketcomp.com.au>

Newsgroups:

microsoft.public.vc.mfc

Date:

Sat, 9 Feb 2008 18:10:45 +0000

Message-ID:

<eaK2nb0aIHA.1208@TK2MSFTNGP03.phx.gbl>

"ole.tetzschner@gmail.com" <ole.tetzschner@gmail.com> wrote in message
news:205d9ae8-4e3e-4eb6-95d7-6265933c60c6@l16g2000hsh.googlegroups.com:

On Feb 9, 5:25 pm, Joseph M. Newcomer <newco...@flounder.com> wrote:

If you are leaking from a "CFrameWnd" object, it is unlikely that it

is a CWinThread

object. Could you show the message?

Normally, when you create a CWinThread-derived thread, the

m_bAutoDelete flag is TRUE, and

therefore the CWinThread object will be automatically deleted when the

thread terminates.

This would be verified by the fact that an attempt to delete it a

second time results in a

catastrophic failure. So it is unlikely that it is your CmyUIthread

object. But make

sure the destructors for that object delete anything it had allocated;

for example, if it

had a CWhatever* pointer in it, its destructor had better delete that

object (unless

someone else has responsibility for deleting it)
joe

On Sat, 9 Feb 2008 07:21:14 -0800 (PST), ole.tetzsch...@gmail.com

wrote:

Hi

I guess it's just me being stupid, but I been googling and trying for
hours now and can't solve this problem myself.

The Problem is I have created a class (CmyUIthread) derived from
CWinThread, but when my test-app exit the compiler reports a memory
leak from a CFrameWnd object.

My test-app is just a dialog-app with 2 buttons. The first button

just

create and starts the ui-thread:

   m_p_thread = new CmyUIthread;
   m_p_thread->CreateThread();

And the tread starts perfect :)

The second button stops the thread:

   m_p_thread->PostThreadMessage( WM_QUIT,0,0);

And the thread stops :)

But when i quit my dlg-test-app the compiler reports the memory
leak???

I tried adding a third button that:

   delete m_p_thread;

but this results in access violations.

CmyUIthread looks like this:

CmyUIthread::CmyUIthread()
{
}

CmyUIthread::~CmyUIthread()
{
}

BOOL CmyUIthread::InitInstance()
{
   // TODO: perform and per-thread initialization here
   CFrameWnd *wnd = new CFrameWnd;
   wnd->Create( NULL, "myUIthread Window");
   wnd->ShowWindow( SW_SHOW);
   wnd->UpdateWindow();
   m_pMainWnd = wnd;

   return TRUE;
}

int CmyUIthread::ExitInstance()
{
   // TODO: perform any per-thread cleanup here
   return CWinThread::ExitInstance();
}

BEGIN_MESSAGE_MAP(CmyUIthread, CWinThread)
END_MESSAGE_MAP()

What is wrong??? do I miss some cleanup???

With kind regards.. Ole

Joseph M. Newcomer [MVP]
email: newco...@flounder.com
Web:http://www.flounder.com
MVP Tips:http://www.flounder.com/mvp_tips.htm

Hi Joseph

Thanks for you quick reply :)

The messages is:

The thread 'Win32 Thread' (0x6c0) has exited with code 0 (0x0).
Detected memory leaks!
Dumping objects ->
f:\sp\vctools\vc7libs\ship\atlmfc\src\mfc\strcore.cpp(141) : {105}
normal block at 0x003A74D0, 34 bytes long.
Data: <, ?x > 2C 08 3F 78 11 00 00 00 11 00 00 00 01 00 00
00
{104} client block at 0x003A98B0, subtype c0, 212 bytes long.
a CFrameWnd object at $003A98B0, 212 bytes long

Seems pretty obvious what hasn't been cleaned up. What you create you
are reponsible for removing.

You have to close or Destroy your CFrameWnd. It would be easier to
derive a new class from CFrameWnd so you can handle messages for it.
But, as said, it is easier to have your window in the main thread and
pass a reference to it across to your thread.

Object dump complete.
The program '[3232] myThreadTest.exe: Native' has exited with code 2
(0x2).

This is a fresh wizard-generated dialog project where I add the
CWinThread derived class also by the wizard. The only code I added to
CmyUIthread is in the InitInstance... and changed the destructor and
constructor to public (so I could use the "new" to generate the object
in my dialog-test-app).

What is it I need to clean-up ???

With kind regards... Ole