Notifications for file system changed?

Question

I'm implementing a free space on disk bar where while files are being copied, the free space bar updates. I need some way of being notified of file system changes. What's the best way to go about doing this?

Answer 1

The File System Events Programming Guide has all the info you need. You want to register with the File System Events API (OS X 10.5 and later).

Answer 2

To monitor operations on individual files you can use kqueue file change notifications. Uli Kusterer has a nice Obj-C wrapper called UKKQueue.

You can get it here: http://zathras.de/angelweb/sourcecode.htm

If you want to watch an entire folder, FSEvents (and the SCEvents wrapper) will probably be of more use.