Re: CEvent & WaitForSingleObject (auto-reset)

From:
"Alexander Grigoriev" <alegr@earthlink.net>
Newsgroups:
microsoft.public.vc.mfc
Date:
Thu, 2 Jul 2009 07:24:16 -0700
Message-ID:
<uSuBJDy#JHA.1336@TK2MSFTNGP05.phx.gbl>
You can't use your CEvent pointer as an argument of WaitForSingleObject.
It's not an event handle.

And first of all, DON'T USE CEvent. Use ATL::CEvent, which is more sane.
MFC::CEvent is braindead.

"Jimbo_Jimbob_Jiminator" <JimboJimbobJiminator@discussions.microsoft.com>
wrote in message news:17FE98C0-D85E-4BF4-B154-7C303795B479@microsoft.com...

Haven't been here in a while. Haven't been doing any Windows programming
for
some time.

I have an issue with CEvent & WaitForSingleObject. The likely issue is
that
I have no idea what I'm doing but, if we put that aside and pretend that I
have a clue, it goes like this:

The default implementation for CEvent is auto-reset. That is how I want to
use it. I have only a main tread and a second thread so I do not have
several
threads waiting.

I have looked in books and all over the web and all of the examples seem
to
show how to start a thread or stop a thread with an event. In this case,
auto-reset is not that useful if you only have one worker thread anyway.

I am trying to control when a loop runs with the event. The issue is that
once the user clicks the button to allow the progress bar to be updated
once,
it just keeps updating through completion. I figure that the state of the
CEvent should auto-reset and it should not run another iteration until the
user intiates it.

Regards,
Jim

Here are some code snips that show it:

//This is primarily from an example I found on the web. I added the
//WaitForSingleObject as a test case.
UINT TestThread(LPVOID lParam)
{
AfxMessageBox("Bite Me");

PTHREADINFOSTRUCT pTis = (PTHREADINFOSTRUCT)lParam;
pTis->pEvent->Lock();
for(int i=0;i<100;i++)
{
::WaitForSingleObject(pTis->pEvent, INFINITE) == WAIT_OBJECT_0;
//This sends a message to the main thread to update the status bar
PostMessage(pTis->hWnd,UWM_USER_THRD_UPPRG,i,100);
Sleep(100);
}
PostMessage(pTis->hWnd,UWM_USER_THRD_FIN,0,0);
delete pTis;
return 0;
}

void CPPage1::OnBnClickedButton1()
{
//Testing Wait Single Object. Sends message to main dlg that user clicked
//the button
LRESULT Rslt = ::SendMessage(m_pMainWnd->m_hWnd , UWM_TEST_WSO, 0, 0);
}

LRESULT CMainDlg::OnWSO(WPARAM wParam, LPARAM lParam)
{
//User clicked the button set event to allow progress bar another tick.
pTis->pEvent->SetEvent();
return 0;
}

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