Windows Directory Monitor (WDM)

Windows Directory Monitor (WDM) is a library which can be used to monitor directories for changes. It's mostly implemented in C and uses the Win32 API for a better performance.

Note: This is still a work in progress, so it's not advisable to use it yet in anything (unless you are testing it, which is very much appreciated :)).


  • Fix all the TODO's in the source.
  • ~~Enable watching subdirectories.~~
  • ~~Add options to the watch method.~~
  • ~~Provide info about the change in the callback.~~
  • ~~Convert \ to / in paths.~~
  • ~~Don't allow directories to be watched while the monitor is running.~~
  • ~~Check if the passed direcoty exists.~~
  • ~~Convert passed directories to absolute paths.~~


Add this line to your application's Gemfile:

gem 'wdm'

And then execute:

$ bundle

Or install it yourself as:

$ gem install wdm

Compiling the extension for developers

Download the source, then run the following:

$ rake compile

To get debug messages, you need to enable them in the global.h file:

#define WDM_DEBUG_ENABLED TRUE // This is disabled by default


TODO: Write usage instructions here


  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Added some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request


Maher Sallam