ruby - Ruby 多线程的奇怪行为

Question

我正在尝试了解 Ruby 多线程，但它看起来很困惑。这是我尝试过的几个例子:

1. 线程永远不会被执行并且程序结束

Thread.new do
  puts "thread"
end

puts "main"

线程已执行但从未终止

thread = Thread.new do
  puts "thread"
end

sleep while thread.alive?

puts "main"

一切都出乎意料地按预期进行:

thread = Thread.new do
  puts "thread"
end

puts thread.status while thread.alive?

puts "main"

Matz 到底是怎么回事？!

Answer 1

Thread never gets executed and program ends

Thread.new do
  puts "thread"
end

puts "main"

线程并行运行。 Ruby 主进程不会自动等待所有线程完成后再退出。

您缺少的是 join 。这将等待线程完成。

thread = Thread.new do
  puts "thread"
end

puts "main"

thread.join

---

Thread is executed but never terminates

thread = Thread.new do
  puts "thread"
end

sleep while thread.alive?

puts "main"

sleep没有争论就永远沉睡。给它一个短暂的 sleep 时间，它就会起作用。

thread = Thread.new do
  puts "thread"
end

sleep(0.1) while thread.alive?

puts "main"

---

Everything unexpectedly works as expected:

thread = Thread.new do
  puts "thread"
end

puts thread.status while thread.alive?

puts "main"

既然您没有永远 sleep ，它就会按预期工作。