Re: Monitor a directory using WaitForMultipleObjects

From:

"Ben Voigt" <rbv@nospam.nospam>

Newsgroups:

microsoft.public.vc.language

Date:

Wed, 21 Mar 2007 11:06:00 -0500

Message-ID:

<OCsszJ9aHHA.4000@TK2MSFTNGP02.phx.gbl>

<alokmahto2007@gmail.com> wrote in message
news:1174491590.597406.231050@e1g2000hsg.googlegroups.com...

Platform : Windows2000, XP,

Microsoft Visual C++ .NET (Version 7.1)

I need to process the files in a directory immediately the moment it
gets
deposited in a directory.
I am trying to achieve this by running WaitForMultipleObjects ,
FindFirstChangeNotificationAPI, FindNextChangeNotification in a
While
loop

When I use dos command copy in batch file for copying file from
one folder to other

then my application reads from the destination directory smoothly.

But when I use move command, file moved from one directory to another
but my aplication does not read the file from the directory.

Move doesn't create a new file.... you need to watch for
FILE_NOTIFY_CHANGE_FILE_NAME as well.

(Please see excerpts of code below:)
int CMyWorkThread::Run()
{
ASSERT_VALID(GetWork());
CDirEventReceiverWork* dirWrk =
dynamic_cast<CDirEventReceiverWork*>(GetWork());
try
{
DWORD timeout = GetCycleTime();
BOOL waitAll = FALSE;
DWORD dwWaitStatus;
while (TRUE)
{
try
{
dirWrk->GetEventDirectoryList(con);
dwChangeHandle= FindFirstChangeNotification ( lpDir, // directory to
watch
subDirState, // do not watch subtree
FILE_NOTIFY_CHANGE_CREATION |FILE_NOTIFY_CHANGE_LAST_WRITE); //
watch file name changes

AddToHandleMap(dwChangeHandle, &ci);

dwChangeHandles = GetHandleList();

int nHandles = m_pDirEventServer.GetHandleMap().size()+ 2;

dwWaitStatus = WaitForMultipleObjects(nHandles, dwChangeHandles,

waitAll, timeout);

if(dwWaitStatus == WAIT_TIMEOUT )

{
//Refresh receiver list
continue;
}
if((dwWaitStatus == WAIT_OBJECT_0 + 0) || (dwWaitStatus ==
WAIT_OBJECT_0
+ 1) )
{
//signalled kill event
break;
}

if((dwWaitStatus <= (WAIT_OBJECT_0 +1)) || (dwWaitStatus >=
nHandles))

{
ASSERT(false);
ostringstream ost;
ost << "Invalid wait return value [" << dwWaitStatus << "]";
CABIException(PROGRAM_ERROR, ost.str(), __FILE__, __LINE__);
continue;
}

if(dwWaitStatus == m_pDirEventServer.GetHandleMap().size())
{
//signalled kill event
break;
}

//Process the files
}

Any suggestion or solution will be the great help for me.
Regards

Alok Mahto