Mac::FSEvents - Monitor a directory structure for changes


  use Mac::FSEvents;

  my $fs = Mac::FSEvents->new( {
      path    => '/',       # required, the path to watch
      latency => 2.0,       # optional, time to delay before returning events
      since   => 451349510, # optional, return events from this eventId
  } );

  my $fh = $fs->watch;

  # Select on this filehandle, or use an event loop:
  my $sel = IO::Select->new($fh);
  while ( $sel->can_read ) {
      my @events = $fs->read_events;
      for my $event ( @events ) {
          printf "Directory %s changed\n", $event->path;

  # or use blocking polling:
  while ( my @events = $fs->read_events ) {

  # stop watching


This module implements the FSEvents API present in Mac OSX 10.5 and later. It enables you to watch a large directory tree and receive events when any changes are made to directories or files within the tree.

Event monitoring occurs in a separate C thread from the rest of your application.


new ( { ARGUMENTS } )

Create a new watcher. A hash reference containing arguments is required:


Required. The full path to the directory to watch. All subdirectories beneath this directory are watched.


Optional. The number of seconds the FSEvents service should wait after hearing about an event from the kernel before passing it along. Specifying a larger value may result in fewer callbacks and greater efficiency on a busy filesystem. Fractional seconds are allowed.

Default: 2.0


Optional. A previously obtained event ID may be passed as the since argument. A notification will be sent for every event that has happened since that ID. This can be useful for seeing what has changed while your program was not running.


Begin watching. Returns a filehandle that may be used with select() or the event loop of your choice.


Returns an array of pending events. If using an event loop, this method should be called when the filehandle becomes ready for reading. If not using an event loop, this method will block until an event is available.

Events are returned as Mac::FSEvents::Event objects.


Stop watching.



Andy Grundman, <>


Copyright (C) 2009 by Andy Grundman

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.8 or, at your option, any later version of Perl 5 you may have available.