EventMachine gem workaround causes missing dll file ruby error, Windows 7

Question

Upon cloning my first Rails 3.1.1 app, my first bundle install choked on the eventmachine 0.12.10 gem. (I'm running Windows 7 32 bit)

I'm also using gem 'thin' as well.

I found this post that had the same problem.

Which version of eventmachine is able to work in windows?

Which I integrated with this line in my gemfile:

gem "eventmachine", ">= 1.0.0.beta"

That allowed the bundle install to run but when I start the rails server I get a Ruby popup with the header ruby.exe - System Error and the text

The program can't start because libgcc_s_sjlj-1.dll is missing from your computer.  Try reinstalling the program to fix this problem.

After I click OK I get this message in the console

Unable to load the EventMachine C extension; To use the pure-ruby reactor, require 'em/pure_ruby'

followed by a long stack trace (request to see if you think this will help).

I see that EventMachine gem requires a C++ compiler. I reinstalled MinGW on my 32 bit Windows 7 machine and I added MinGW\bin to my PATH variable.

But when I look into that bin folder, the file libgcc_s_sjlj-1.dll isn't there and the same error message persists. I found this thread about the lack of that folder from 2009 but I'm not really sure what to do about it.

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=539033

Thanks for any help you can give me.

Answer 1

I solved this problem by adding

require "em/pure_ruby"

in the config/application.rb

Hope this could help.

Answer 2

This is probably because eventmachine is dynamically linked to the mingw dlls.

You can:

require 'devkit'

on the top of your script. This will temporarily enhance your path with the path to the mingw devkit.

Source

Answer 3

Add this to your gem file

gem 'eventmachine', '1.0.0.beta.4.1'

Also note that if you switch back to a unix based OS, you will have to use 1.0.0.beta.4.