The FindFirstChangeNotification function 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.
HANDLE FindFirstChangeNotification(
| LPCTSTR lpPathName, | // pointer to name of directory to watch |
| BOOL bWatchSubtree, | // flag for monitoring directory or directory tree |
| DWORD dwNotifyFilter | // filter conditions to watch for |
| ); |
Parameters
lpPathName
Points to a null-terminated string that specifies the path of the directory to watch.
bWatchSubtree
Specifies whether the function will monitor the directory or the directory tree. 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.
dwNotifyFilter
Specifies the filter conditions that satisfy a change notification wait. This parameter can be one or more of the following values:
| Value | Meaning | ||||
| FILE_NOTIFY_CHANGE_FILE_NAME | |||||
| Any filename change in the watched directory or subtree causes a change notification wait operation to return. Changes include renaming, creating, or deleting a filename. | |||||
| FILE_NOTIFY_CHANGE_DIR_NAME | |||||
| Any directory-name change in the watched directory or subtree causes a change notification wait operation to return. Changes include creating or deleting a directory. | |||||
| FILE_NOTIFY_CHANGE_ATTRIBUTES | |||||
| Any attribute change in the watched directory or subtree causes a change notification wait operation to return. | |||||
| FILE_NOTIFY_CHANGE_SIZE | |||||
| Any file-size change in the watched directory or subtree causes a change notification wait operation to return. The operating system detects a change in file size only when the file is written to the disk. For operating systems that use extensive caching, detection occurs only when the cache is sufficiently flushed. | |||||
| FILE_NOTIFY_CHANGE_LAST_WRITE | |||||
| Any change to the last write-time of files in the watched directory or subtree causes a change notification wait operation to return. The operating system detects a change to the last write-time only when the file is written to the disk. For operating systems that use extensive caching, detection occurs only when the cache is sufficiently flushed. | |||||
| FILE_NOTIFY_CHANGE_SECURITY | |||||
| Any security-descriptor change in the watched directory or subtree causes a change notification wait operation to return. | |||||
Return 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.
Remarks
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.
See Also