results

--> started at 2013-06-27 19:14:48 +0800
counter1 : 367240
counter2 : 367240
difference : 0
--> end at 2013-06-27 19:14:49 +0800

thread_learn_1.rb

#!/usr/bin/ruby
require 'thread'

mutex = Mutex.new                           # 生成锁对象
counter1 = counter2 = 0
difference = 0

puts "--> started at #{Time.now}"
t1 = Thread.new do                          # new/start/fork是alias的方法，基本功能相同。
  loop do
    mutex.synchronize do                    # 同步锁
      counter1 += 1
      counter2 += 1
    end
  end
end
t2 = Thread.new do
  loop do
    mutex.synchronize do                     # 同步锁，控制读写
      difference += (counter1 - counter2).abs
    end
  end
end
sleep 1
puts "counter1 : #{counter1}"
puts "counter2 : #{counter2}"
puts "difference : #{difference}"
#t1.join                                     # 阻塞当前线程，当t1线程运行结束后，阻塞线程重新进入运行状态。相当于将线程同步执行
#t2.join
puts "--> end at #{Time.now}"