编写一个肯定会进入死锁的程序 [英] Write a program that will surely go into deadlock

问题描述

我最近在面试中遇到了这个问题。

我回答说，如果交错错误，就会发生死锁，但是访问者坚持认为程序总是会进入死锁而不管交织是否可以写。

我们可以写这样的程序吗？你能指点我这样的示例程序吗？

解决方案

更新：这个问题是我的博客在2013年1月的主题。非常感谢您提出的问题！

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我们如何编写一个程序

这是C＃中的一个例子。请注意，该程序似乎不包含锁定和共享数据。它只有一个局部变量和三个语句，但它的死锁有100％的确定性。

练习读者＃1：解释一下死锁。 （答案在注释中。）

练习读者＃2：在Java中演示同样的死锁。 （答案在这里： http://stackoverflow.com/a/9286697/88656 ）

class MyClass
{
static MyClass（）
{
//让我们在另一个线！
var thread = new System.Threading.Thread（Initialize）;
thread.Start（）;
thread.Join（）;
}

static void Initialize（）
{/ * TODO：添加初始化代码* /}

static void Main（）
{}
}


I recently got this questions asked in an interview.

I answered that deadlock occurs if the interleaving goes wrong, but the interviewer insisted that a program that will always go into deadlock regardless of interleaving can be written .

Can we write such a program ? Can you point me to some example program like that ?

解决方案

UPDATE: This question was the subject of my blog in January 2013. Thanks for the great question!

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How can we write a program that will always go into deadlock no matter how the threads are scheduled?

Here's an example in C#. Note that the program appears to contain no locks and no shared data. It has only a single local variable and three statements, and yet it deadlocks with 100% certainty. One would be hard-pressed to come up with a simpler program that deadlocks with certainty.

Exercise to the reader #1: explain how this deadlocks. (An answer is in the comments.)

Exercise to the reader #2: demonstrate the same deadlock in Java. (An answer is here: http://stackoverflow.com/a/9286697/88656)

class MyClass
{
  static MyClass() 
  {
    // Let's run the initialization on another thread!
    var thread = new System.Threading.Thread(Initialize);
    thread.Start();
    thread.Join();
  }

  static void Initialize() 
  { /* TODO: Add initialization code */ }

  static void Main() 
  { }
}

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