Re: Monitor a directory using WaitForMultipleObjects

Thanks for your prompt reply Igor.
I am sorry for not having put the whole code snippet, probably thats why my
problem is not clear.
My code does some what the same as what you have suggested i.e.
FindFirstChangeNotification before the while(wait), then the FindNext for
each directory after the Wait. Basically the FindNext function is a part of
another function of a different class , I have included it for your
reference this time.
My problem is a bit more complex as I am not monitoring a single directory
but a list of directories, so I believe there will definitely be a lapse
between the directories.
I am not sure whether there could be anything wrong in what is being done
......any pointers would be of great help.
Please let me know if you think it could be bettered or some other option
could be used.
I am including the whole code below

Thanks and Regards
Ganga

int CABIEventWorkThread::Run()

{

ASSERT_VALID(GetWork());

CDirEventReceiverWork* dirWrk =
dynamic_cast<CDirEventReceiverWork*>(GetWork());

try

{

COMMINFOCON con;

dirWrk->GetEventDirectoryList(con);

dirWrk->RunOnce();

HANDLE* dwChangeHandles;

DWORD timeout = GetCycleTime();

BOOL waitAll = FALSE;

DWORD dwWaitStatus;

while (TRUE)

{

try

{

dirWrk->GetEventDirectoryList(con);

m_pDirEventServer.WatchDirectories(con);

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;

}

try

{

CCommInfo ci = m_pDirEventServer.SetNextChangeNotification

(dwWaitStatus , dwChangeHandles);

dirWrk->SetCommInfo(ci);

//Process the directory

dirWrk->DoWork(GetWork());

}

catch(CABIException e)

{

ostringstream ost;

ost << e.ReportError();

CABIException(PROGRAM_ERROR, ost.str(), __FILE__, __LINE__);

continue;

}

}

catch(CABIException e)

{

ostringstream ost;

ost << e.ReportError();

CABIException(PROGRAM_ERROR, ost.str(), __FILE__, __LINE__);

continue;

}

}

}

catch(...)

{

ostringstream ost;

ost << "Caught Unknown Exception while doing Directory receiver Work";

CABIException(PROGRAM_ERROR, ost.str(), __FILE__, __LINE__);

}

try

{

//signalled externally for killing myself

EndWork(); //do derived shutdown

}

catch(CABIException& e)

{

ASSERT(false);

}

catch(CException* e)

{

ASSERT(false);

char szErr[1024];

e->GetErrorMessage(szErr, 1024);

e->Delete();

ostringstream ost;

ost << "Caught CException while executing EndWork(), with error [" << szErr
<< "]. Rebulidng ABI Exception";

CABIException(PROGRAM_ERROR, ost.str(), __FILE__, __LINE__);

}

catch(exception& e)

{

ASSERT(false);

ostringstream ost;

ost << "Caught exception while executing EndWork(), with error [" <<
e.what() << "]. Rebulidng ABI Exception";

CABIException(PROGRAM_ERROR, ost.str(), __FILE__, __LINE__);

}

catch(...)

{

//this should never happen unless there is problem destroying

//work object (bad pointer)

ASSERT(false);

ostringstream ost;

ost << "Caught unknown exception while executing EndWork(). Rebulidng ABI
Exception";

CABIException(PROGRAM_ERROR, ost.str(), __FILE__, __LINE__);

}

SetEvent(GetEventDead()); //signal to calling thread that i am done

SetEvent(GetEventAnotherDead()); //signal to calling thread that i am done

AfxEndThread(0,m_bAutoDelete);

return 0;

}

void CDirEventServer::WatchDirectories(const COMMINFOCON& con)

{

HANDLE dwChangeHandle;

TCHAR lpDrive[4];

TCHAR lpFile[_MAX_FNAME];

TCHAR lpExt[_MAX_EXT];

StopWatch();

for(COMMINFOCON::const_iterator It = con.begin(); It != con.end(); It++)

{

const CCommInfo& ci =(*It);

string strPath = ci.GetRemoteDir();

const TCHAR* lpDir = strPath.c_str();

bool subDirState = ci.IsSubDirectory();

_tsplitpath(lpDir, lpDrive, NULL, lpFile, lpExt);

lpDrive[2] = (TCHAR)'\\';

lpDrive[3] = (TCHAR)'\0';

// Watch the directory for file creation and deletion.

dwChangeHandle= FindFirstChangeNotification(

lpDir, // directory to watch

subDirState, // do not watch subtree

FILE_NOTIFY_CHANGE_CREATION |

FILE_NOTIFY_CHANGE_LAST_WRITE); // watch file name changes

if (dwChangeHandle == INVALID_HANDLE_VALUE)

{

ostringstream ost;

ost << "FindFirstChangeNotification returned an INVALID_HANDLE_VALUE";

throw CABIException(PROGRAM_ERROR,ost.str(),__FILE__,__LINE__);

}

AddToHandleMap(dwChangeHandle, &ci);

}

}

CCommInfo CDirEventServer::SetNextChangeNotification(long lWait, HANDLE*
dwChangeHandles)

{

HANDLECOMMINFOMAP::iterator It =
GetHandleMap().find(dwChangeHandles[lWait]);

if (lWait >= 0 && It != GetHandleMap().end())

{

const CCommInfo* ci = (*It).second;

ASSERT(lWait < GetHandleMap().size()+2);

if (FindNextChangeNotification(

dwChangeHandles[lWait]) == FALSE)

{

ostringstream ost;

ost << "FindNextChangeNotification returned an INVALID_HANDLE_VALUE";

throw CABIException(PROGRAM_ERROR,ost.str(),__FILE__,__LINE__);

}

return *ci;

}

else

{

ostringstream ost;

ost << "Invalid Handle Wait state";

throw CABIException(PROGRAM_ERROR, ost.str(), __FILE__, __LINE__);

}

}

"Igor Tandetnik" <itandetnik@mvps.org> wrote in message
news:OOJySP7kGHA.1640@TK2MSFTNGP02.phx.gbl...