Thread Join

A thread runs work independently, and join waits for it to finish.

thread_join.rb

work_units = 
result = 0

worker = Thread.new do
  subtotal = work_units * 10
  result = subtotal + 1
end

worker.join

puts "work_units=#{work_units}"
puts "result=#{result}"
puts "worker_done=#{!worker.alive?}"

work_units = 
result = 0

worker = Thread.new do
  subtotal = work_units * 10
  result = subtotal + 1
end

worker.join

puts "work_units=#{work_units}"
puts "result=#{result}"
puts "worker_done=#{!worker.alive?}"

work_units = 
result = 0

worker = Thread.new do
  subtotal = work_units * 10
  result = subtotal + 1
end

worker.join

puts "work_units=#{work_units}"
puts "result=#{result}"
puts "worker_done=#{!worker.alive?}"

thread join `Thread.new` starts a block on another Ruby thread. `join` keeps the main code from reading the result too early.