# Thread #1 is running here
Thread.new {
 # Thread #2 runs this code
}
# Thread #1 runs this code

#!/usr/bin/ruby

def func1
  i=0
  while i<=2
   puts "func1 at: #{Time.now}"
   sleep(2)
   i=i+1
  end
end

def func2
  j=0
  while j<=2
   puts "func2 at: #{Time.now}"
   sleep(1)
   j=j+1
  end
end

puts "Started At #{Time.now}"
t1=Thread.new{func1()}
t2=Thread.new{func2()}
t1.join
t2.join
puts "End at #{Time.now}"

Started At Wed May 14 08:21:54 -0700 2008
func1 at: Wed May 14 08:21:54 -0700 2008
func2 at: Wed May 14 08:21:54 -0700 2008
func2 at: Wed May 14 08:21:55 -0700 2008
func1 at: Wed May 14 08:21:56 -0700 2008
func2 at: Wed May 14 08:21:56 -0700 2008
func1 at: Wed May 14 08:21:58 -0700 2008
End at Wed May 14 08:22:00 -0700 2008

t = Thread.new { ... }
t.abort_on_exception = true

#!/usr/bin/ruby

count = 0
arr = []

10.times do |i|
  arr[i] = Thread.new {
   sleep(rand(0)/10.0)
   Thread.current["mycount"] = count
   count += 1
  }
end

arr.each {|t| t.join; print t["mycount"], ", " }
puts "count = #{count}"

8, 0, 3, 7, 2, 1, 6, 5, 4, 9, count = 10

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

count1 = count2 = 0
difference = 0
counter = Thread.new do
  loop do
   count1 += 1
   count2 += 1
  end
end
spy = Thread.new do
  loop do
   difference += (count1 - count2).abs
  end
end
sleep 1
puts "count1 : #{count1}"
puts "count2 : #{count2}"
puts "difference : #{difference}"

count1 : 1583766
count2 : 1583766
difference : 637992

#!/usr/bin/ruby
require 'thread'
mutex = Mutex.new

count1 = count2 = 0
difference = 0
counter = Thread.new do
  loop do
   mutex.synchronize do
     count1 += 1
     count2 += 1
   end
  end
end
spy = Thread.new do
  loop do
    mutex.synchronize do
     difference += (count1 - count2).abs
    end
  end
end
sleep 1
mutex.lock
puts "count1 : #{count1}"
puts "count2 : #{count2}"
puts "difference : #{difference}"

count1 : 696591
count2 : 696591
difference : 0

#!/usr/bin/ruby
require 'thread'
mutex = Mutex.new

cv = ConditionVariable.new
a = Thread.new {
  mutex.synchronize {
   puts "A: I have critical section, but will wait for cv"
   cv.wait(mutex)
   puts "A: I have critical section again! I rule!"
  }
}

puts "(Later, back at the ranch...)"

b = Thread.new {
  mutex.synchronize {
   puts "B: Now I am critical, but am done with cv"
   cv.signal
   puts "B: I am still critical, finishing up"
  }
}
a.join
b.join

A: I have critical section, but will wait for cv
(Later, back at the ranch...)
B: Now I am critical, but am done with cv
B: I am still critical, finishing up
A: I have critical section again! I rule!

Thread.abort_on_exception = true

#!/usr/bin/ruby

thr = Thread.new do  # Calling a class method new
  puts "In second thread"
  raise "Raise exception"
end
thr.join  # Calling an instance method join