From: John Bob <johnbob31@...>
Date: 2009-07-26T07:18:08+09:00
Subject: C extension and Ruby threads

Hi all,
I've found something a bit weird while trying to make a C extension
wrapping a custom network library :
 - My extension creates a BaseClient class with a method 'receive' (it
basically wait a response from a server for a given period of time)
 - I created a ruby class Client that inherits from BaseClient. In the
constructor of this class, I create a thread that loops on the method
receive(). Note that in my C code, the receive function does a
WaitForSingleObject (Windows equivalent of pthread_cond_wait ) with a
timeout of 100ms

My problem is that even if my reception thread is in a wait state, my
main thread doesn't run smoothly (it freezes while the other thread
calls Client#receive).
I tried to place a Thread.pass between each iteration of the loop,
that's a little better but still far from what I expected.

Tested on Ruby 1.8.7 and ruby 1.9.1 (thought that native threads would
solve my problem, but not at all).

My code is the following :

require 'TestClientBase'
  class Client < ClientBase

      def initialize()
        @thread = Thread.new(self) {
          |client|
          fin = false
          while fin != true
           msg = client.receive(100)
           case msg
            when TIME_OUT
               puts ("Timeout")
            when SERV_CLOSED
               fin = true
           end
           Thread.pass
          end
        }
        @thread.priority = -1
      end
      def wait()
          @thread.join(10.0)
      end
  end


client = Client.new

100.times {
  puts "Time=#{Time.now}"
}

client.wait()


Thanks for you replies.
-- 
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