FindFirstChangeNotificationA function (fileapi.h)
Creates a change notification handle and sets up initial change notification filter conditions. A wait on a notification handle succeeds when a change matching the filter conditions occurs in the specified directory or subtree. The function does not report changes to the specified directory itself.
This function does not indicate the change that satisfied the wait condition. To retrieve information about the specific change as part of the notification, use the
HANDLE FindFirstChangeNotificationA( [in] LPCSTR lpPathName, [in] BOOL bWatchSubtree, [in] DWORD dwNotifyFilter );
The full path of the directory to be watched.
This cannot be a relative path or an empty string.
By default, the name is limited to MAX_PATH characters. To extend this limit to 32,767 wide characters, prepend "\\?\" to the path. For more information, see Naming Files, Paths, and Namespaces.
Starting with Windows 10, Version 1607, you can opt-in to remove the MAX_PATH limitation without prepending "\\?\". See the "Maximum Path Length Limitation" section of Naming Files, Paths, and Namespaces for details.
If this parameter is TRUE, the function monitors the directory tree rooted at the specified directory; if it is FALSE, it monitors only the specified directory.
The filter conditions that satisfy a change notification wait. This parameter can be one or more of the following values.
If the function succeeds, the return value is a handle to a find change notification object.
If the function fails, the return value is INVALID_HANDLE_VALUE. To get extended error information, call GetLastError.
The wait functions can monitor the specified directory or subtree by using the handle returned by the FindFirstChangeNotification function. A wait is satisfied when one of the filter conditions occurs in the monitored directory or subtree.
After the wait has been satisfied, the application can respond to this condition and continue monitoring the directory by calling the FindNextChangeNotification function and the appropriate wait function. When the handle is no longer needed, it can be closed by using the FindCloseChangeNotification function.
Notifications may not be returned when calling FindFirstChangeNotification for a remote file system.
Symbolic link behavior—If the path points to a symbolic link, the notification handle is created for the target.
If an application has registered to receive change notifications for a directory that contains symbolic links, the application is only notified when the symbolic links have been changed, not the target files.
In Windows 8 and Windows Server 2012, this function is supported by the following technologies.
|Server Message Block (SMB) 3.0 protocol||Yes|
|SMB 3.0 Transparent Failover (TFO)||Yes|
|SMB 3.0 with Scale-out File Shares (SO)||Yes|
|Cluster Shared Volume File System (CsvFS)||See remark|
|Resilient File System (ReFS)||Yes|
Application might experience false positives on CsvFs pause/resume.
For an example, see Obtaining Directory Change_Notifications.
The fileapi.h header defines FindFirstChangeNotification as an alias which automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes.
|Minimum supported client||Windows XP [desktop apps only]|
|Minimum supported server||Windows Server 2003 [desktop apps only]|
|Header||fileapi.h (include Windows.h)|