(PECL inotify >= 0.1.2)
inotify_add_watch — Add a watch to an initialized inotify instance
inotify_add_watch() adds a new watch or modify an existing watch for the file or directory specified in pathname .
Using inotify_add_watch() on a watched object replaces the existing watch. Using the IN_MASK_ADD constant adds (OR) events to the existing watch.
Resource returned by inotify_init()
File or directory to watch
Events to watch for. See Predefined Constants.
The return value is a unique (inotify instance wide) watch descriptor.