Ruby SystemTimer gem for Windows

Posted in code, ruby on rails by mtjhax on December 23, 2010

SystemTimer is a Gem that replaces timeout.rb and fixes some potentially serious flaws when accessing system resources (e.g., when communicating with remote APIs) in Linux/Posix environments. In a nutshell, timeout.rb uses Ruby pseudo-threads (“green threads”) that are not guaranteed to be given the same equal opportunities in the CPU as real system threads, resulting in synchronization problems. Visit for all the details.

If you end up needing to use SystemTimer on your production environment and you develop on Windows, you have a problem. SystemTimer’s documentation says that it can be installed under Windows (providing the same interface for your code but not really changing anything — it just acts as a wrapper to timeout.rb). In practice, however, trying to “gem install SystemTimer” results in errors building the native extensions even if you have the RubyInstaller DevKit installed.

Solution? Simple! I don’t know who ghazel is but my hat’s off to them. They took the time to branch the SystemTimer project, patch it to install under Windows and simply provide the wrapper classes without trying to compile anything, and put it up on

Visit or just “gem install ghazel-SystemTimer” and you should be good to go on your Windows development box in about two seconds.