WaitForMultipleObjects , threads and blocking function

mosfet <john.doe@anonymous.org>
Wed, 02 Apr 2008 14:32:02 +0200

I would like some help about a problem about Threading and blocking
We have developped a c++ wrapper around wininet to post some specific data.

Here is the architecture :

A thread always running and waiting on two events, when the event
m_hStartRequest is signaled the HTTP request is written to server and
once it has finished it send an event to inform the caller that the
request is done.

DWORD WINAPI CHttpAdapter::ThrRequestAction( IN LPVOID lpvThreadParam )
      HANDLE WaitHnd[2] = {0};

      CHttpAdapter* pThis = (CHttpAdapter*) lpvThreadParam;
      if ( pThis == NULL ) {
        return -1;

      WaitHnd[0] = pThis->m_hStartRequest;
      WaitHnd[1] = pThis->m_hExitThread;

      while (1)

      DWORD dwRet = WaitForMultipleObjects( 2, WaitHnd, FALSE, INFINITE);
      if ((dwRet == WAIT_OBJECT_0)) {
    // Start our http request
    BOOL bSend = FALSE;
    do {
    NetStream& stream = pThis->m_pRequest->GetRequestStream();
    DWORD dwWrite = stream.Write( pThis->m_pBufferIn, pThis->m_ulSizeIn );
                    ATLTRACE(_T("CHttpAdapter::ThrRequestAction: Sent %d bytes.\n"),
    bSend = stream.Close();
    while( !bSend );

       pThis->m_pWebResp = (HttpWebResponse*)

      ::SetEvent( pThis->m_hRequestDone );

Ret_t CHttpAdapter::SendDataAndParseResponse()
    Ret_t nRet = TP_ERR_OK;
    EHttpErrorKind eHttpErrKind;


    // Inform thread to send the request
    ::SetEvent( m_hStartRequest );

    DWORD dwRetType=::WaitForSingleObject(m_hRequestDone, 60000 );
    if (dwRetType == WAIT_OBJECT_0)
        eHttpErrKind = eHttpErr;
    else if (dwRetType == WAIT_TIMEOUT)
        eHttpErrKind = eTimeoutErr;

    nRet = CheckResponse( eHttpErrKind );

return nRet

The problem arises when the thread is trying to write to server and
server do not respond.
In this case the stream.Write stay blocked and after 1 min the
caller(SendDataAndParseResponse) falls in timeout and in this case
I am trying to release it by calling the HttpEndRequest but it doen't
work ...

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