(PECL inotify >= 0.1.2)
inotify_add_watch — Add a watch to an initialized inotify instance
$inotify_instance, string $pathname, int $mask): int
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.
inotify_instanceinotify_init()返回的資源
pathnameFile or directory to watch
maskEvents to watch for. See 預定義常量.
The return value is a unique (inotify instance wide) watch descriptor.