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“A wrapper class around the kqueue(2) file change notification mechanism.

Simply create a General/UKKQueue, add a few paths to it and listen to the change notifications via General/NSWorkspace’s notification center.”

See also: General/FileSystemNotifications

How can I subscribe a directory situated in a removable media?

The file system has to support the change notifications. Things like NFS and FAT32 don’t have the necessary support to do that (as far as I know)

If the file system does not support kqueues, you can use the traditional General/NSWorkspace notifyFileSystemChanged and corresponding notifications to make things work more or less right. You can also do polling if needed. – General/EmanueleVulcano aka l0ne

General/UKKQueue works quietly, politely, and as advertised. I used it in a recent project and was very pleased to have done so! – General/RobRix

I’m trying to use this, but don’t seem to be getting any notifications. Could anyone help?

I’m setting up the General/UKKQueue as follows.

General/UKKQueue* kqueue = General/[UKKQueue sharedFileWatcher]; General/NSLog(@”adding dir=%@”, [Preferences tvShowDirectory]); [kqueue addPathToQueue:[Preferences tvShowDirectory]]; General/NSWorkspace* workspace = General/[NSWorkspace sharedWorkspace]; General/NSNotificationCenter* notificationCenter = [workspace notificationCenter]; General/NSArray* notifications = General/[NSArray arrayWithObjects: General/NSWorkspaceDidPerformFileOperationNotification, General/NSWorkspaceMoveOperation, General/NSWorkspaceCopyOperation, General/NSWorkspaceLinkOperation, General/NSWorkspaceCompressOperation, General/NSWorkspaceDecompressOperation, General/NSWorkspaceEncryptOperation, General/NSWorkspaceDecryptOperation, General/NSWorkspaceDestroyOperation, General/NSWorkspaceRecycleOperation, General/NSWorkspaceDuplicateOperation, nil];

int i;
for (i=0; i<[notifications count]; i++) {
    General/NSLog(@"Adding notification=%@", [notifications objectAtIndex:i]);
    [notificationCenter addObserver:self selector:@selector(fsHandler:) name:[notifications objectAtIndex:i] object:nil];

General/FsHandler never gets called when I create/touch/delete files within the added file structure. Any suggestions? Thanks!

General/UKFileWatcher/General/UKKQueue doesn’t use those constants as its notification names. See for appropriate notification names.

Yes it always helps to subscribe to the proper notifications. ;) Thanks! Worked like a charm.

General/UKKQueue was written in 2003 and is a bit long in the tooth. There is now a modern, faster, more efficient class that you might consider: General/VDKQueue. You can find it here: