Ruby 1.9.3-p140 - 使用线程 - 如何等待所有结果从线程中出来？

Question

我正在尝试找出一种好方法来等待主线程完成之前执行所有线程。

如何在下面的代码中做到这一点？

    threads = []

    counter = 1000

    lines = 0

    counter.times do |i|
      puts "This is index number #{i}."
    end

    puts "You've just seen the normal printing and serial programming.\n\n"

    counter.times do |i|
      Thread.new do
        some_number = Random.rand(counter)
        sleep 1
        puts "I'm thread number #{i}. My random number is #{some_number}.\n"
        lines += 1
      end
    end

    messaged = false
    while lines < 1000
      puts "\nWaiting to finish.\n" unless messaged
      print '.'
      puts "\n" if lines == 1000
      messaged = true
    end

    puts "\nI've printed #{lines} lines.\n"
    puts "This is end of the program."

程序将我是线程号 XXX。我的随机数是 YYY 与几乎在主线程末尾的 while 循环中的点混合在一起。如果我不使用 while 循环，程序将在线程完成之前完成。

Answer 1

要让父级等待子级完成，请使用 join

 threads = []
 counter.times do |i|
    thr = Thread.new do
            some_number = Random.rand(counter)
            sleep 1
            puts "I'm thread number #{i}. My random number is #{some_number}.\n"
            lines += 1
    end
    threads << thr
  end
  threads.each {|thread| thread.join }