ReadDirectoryChangesW double notification

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C++

Windows

Visual-Studio

MFC

, +

I'm trying to cerate an simple application that is listening to a folder, and everytime a new file is created, moved or copyed to that folder i want to get a notification.
So i created a simple application that creates a seperate thread where i call ReadDirectoryChangesW.
To do this infinitely i have done it into a while(true) loop.

The code is pretty simple (i use ReadDirectoryChangesW in synchronus mode)

while(TRUE)
{
	BYTE						byBuffer[32 * 1024]; // 32 kB
	DWORD						dwOffset = 0;
	TCHAR						cFile[MAX_PATH];
	DWORD						dwBytesRet;
	PFILE_NOTIFY_INFORMATION	pNotify;

	ReadDirectoryChangesW(pWatcher->m_hDir, byBuffer, sizeof(byBuffer), 0, pWatcher->m_dwNotifyFilter, &dwBytesRet, NULL, NULL);

	do
	{
		pNotify = (PFILE_NOTIFY_INFORMATION) &byBuffer[dwOffset];
		dwOffset += pNotify->NextEntryOffset;

		INT nCount = WideCharToMultiByte(CP_ACP, 0, pNotify->FileName, pNotify->FileNameLength / sizeof(WCHAR), cFile, MAX_PATH - 1, NULL, NULL);
		cFile[nCount] = TEXT('\0');

		// Notify me
	}
	while(pNotify->NextEntryOffset != 0);
}

The problem is now, that for every new created file i get two notifications.

It do it in the following order:

1. ReadDirectoryChangesW returns with the new created file
2. move into the do-while loop
3. get the pNotify-pointer
4. calculate the offset
5. Copy the buffer into a TCHAR-array
6. Notify me

up to this point everything is ok



7. NextEntryOffset == 0, so jump outside the do-while loop
8. now loop begins again and run to ReadDirectoryChangesW
9. ReadDirectoryChangesW returns immediately
10. Steps 2-8 again
11. Execution hold on ReadDirectoryChangesW until a new file is created

I have searched at the internet and found this looks lika a common bug. So i have tried to work around the bug with a second string. I compare the second string to the string stored in cFile[] and if they are different, i save cFile to my second string and notify.
That work's fine if only one file is created at a time. But if i copy a bundle of files (for example 4) the solution won't work, because the files doesn't come ordered (if i say ordered i mean File 1, File 1, File 2, File 2, ... they come more like File 1, File 2, File 3, File 4, File 3, File 1, File 4).

So i hope you guys from CodeProject could help me; is there any usable (and pretty) solution for this problem out there?

I' so happy to hear some solutions or ideas from you!
Thank you so much in advance!