help on monitor the folder

[VC123start]

Hi, guru,

I'm a VC beginner and now building a FTP client.

I want to build a programme to monitor the folder like "d:\temp". If a new file is created on the folder, the ftp it to the server.

My question is:

what event or function I need to check there is a new file created on the folder?

rgds,

[Kheun]

Look out for FindFirstChangeNotification(), FindNextChangeNotification(), FindCloseChangeNotification() and WaitForSingleObject().

[VC123start]

Hi, friend,

Thanks for the reply.

I look up some sample of MS and try to use it. But there is a dead loop.

I build the function:
OnButtonClick()
{
function1();
function2();
}

The function1() is OK. For function2():
void function2()
{
DWORD dwWaitStatus;
HANDLE dwChangeHandles;

// Watch the m_strMonitorFolderName directory for file creation
dwChangeHandles = FindFirstChangeNotification(
m_strMonitorFolderName, // directory to watch
FALSE, // do not watch the subtree
FILE_NOTIFY_CHANGE_FILE_NAME); // watch file name changes

if (dwChangeHandles == INVALID_HANDLE_VALUE)
ExitProcess(GetLastError());

while (TRUE)
{

// Wait for notification.
dwWaitStatus = WaitForSingleObject( dwChangeHandles, 0);

if(dwWaitStatus==WAIT_OBJECT_0)
{
function3();
if ( FindNextChangeNotification( dwChangeHandles) == FALSE )
ExitProcess(GetLastError());
}
}

Question:
1. Because I want the programme monitor the folder after strat up, so I use while(true) in function2. But there seems the programme is dead lock after call function2.
2. I want to monitor whether there is a new file created, is that right to use
dwChangeHandles = FindFirstChangeNotification(
m_strMonitorFolderName, // directory to watch
FALSE, // do not watch the subtree
FILE_NOTIFY_CHANGE_FILE_NAME); // watch file name changes
3. I want to programme react immediatly, so whether it is right to use
dwWaitStatus = WaitForSingleObject( dwChangeHandles, 0);

cheers!

[Kheun]

Normally, when WaitForSingleObject() is being used, the current thread will be suspend until timeout or the event occurs. So, to prevent the program from being frozen, it is quite common to spawn-off a thread for the monitoring purpose. This is the reason why your program dead lock.

I am not sure if FILE_NOTIFY_CHANGE_FILE_NAME works but I had tried FILE_NOTIFY_CHANGE_LAST_WRITE before.

AfxBeginThread(NotifyThreadProc, 0)

UINT NotifyThreadProc(LPVOID pParam)
{
	BOOL bKill = FALSE;
	HANDLE hMonitor = NULL;


	// First time for tracking change notification.
	hMonitor = FindFirstChangeNotification(path, FALSE, FILE_NOTIFY_CHANGE_LAST_WRITE );

	while(!bKill)
	{

		//
		// Wait for the change notification.
		//
		DWORD dwWait = WaitForSingleObject(hMonitor, INFINITE);
	
		// Handles the return result.
		switch(dwWait)
		{
		case WAIT_OBJECT_0:
			// Detected a change in the folder.
			// Do something. 

			break;

		case WAIT_ABANDONED:
			// Perform error handling.
			break;

		case WAIT_TIMEOUT:
			// Perform error handling.
			break;

		case WAIT_FAILED:
			// Perform error handling.
			break;

		default:
			break;
		}

		// Subsequent change notification tracking.
		FindNextChangeNotification(hMonitor );
	}

	return 0;	
}

[VC123start]

Cheers! I know a lot because I'm a beginer of VC.

[Kheun]

I'm glad it helps.

[Valentin Rozescu]

hi
i found that thread interesting but i need some advice now

it is possible to know the file that notify me?
i want to know what file was opened from a folder and when

can you help me regarding this problem?
thank you in advance for your help

[Kheun]

ReadDirectoryChangesW().

I had never use this API before but I believe this is what you are looking for. Please tell me if it works. Thanks.

[Kheun]

Hi, I just found a sample from MSDN.

http://msdn.microsoft.com/library/de...hangeswapi.asp