C #, multi-thread deadlock is easy.

Original article: 2008-02-04

In the past few days, it is difficult to check C # multi-thread Dongdong to ensure that multiple threads do not die lock, but it is easy to deadlock. I tried to write a deadlock code. See the following. Environment :. NET 2.0 basic idea: Classic problem when learning OS, two threads seize two resources, thread 1 grab resource A, and resource B; thread 2 grab resource B, resource A is also required; the result is a deadlock.

 1  using System;
 2  using System.Collections.Generic;
 3  using System.Text;
 4  using System.Threading;
 5     
 6  namespace MultiThreadTest
 7  {
 8        class Program
 9     {
10            static void Main(string[] args)
11        {
12      Deadlock#region Deadlock
13                Deadlock DL = new Deadlock();
14                Thread DL1 = new Thread(DL.StartFromLocker1);
15                Thread DL2 = new Thread(DL.StartFromLocker2);
16     
17                DL1.Start();
18                DL2.Start();
19                #endregion
20            }
21     
23        }
24    
25        class Deadlock
26       {
27            object locker1 = new object();
28            object locker2 = new object();
29            string s1="StartFromLocker1", s2="StartFromLocker2";
30            string l1 = "locker1", l2 = "locker2";
31     
32            public void StartFromLocker1()
33           {
34                lock(locker1)
35               {
36                    Console.WriteLine("{0} got {1}", s1, l1);
37                    Thread.Sleep(500);
38                    Console.WriteLine("{0} waiting for {1}", s1, l2);
39                    lock(locker2)
40                    {
41                        Console.WriteLine("{0} got {1}", s1, l2);
42                        Thread.Sleep(500);
43                    }
44                }
45                Console.WriteLine("leaving {0}", s1); 
46            }
47     
48            public void StartFromLocker2()
49           {
50                lock (locker2)
51               {
52                    Console.WriteLine("{0} got {1}", s2, l2);
53                   Thread.Sleep(500);
54                    Console.WriteLine("{0} waiting for {1}", s2, l1);
55                    lock (locker1)
56                   {
57                        Console.WriteLine("{0} got {1}", s2, l1);
58                        Thread.Sleep(500);
59                    }
60                }
61                Console.WriteLine("leaving {0}", s2); 
62            }
63        };
64   }

Running result:

StartFromLocker1 got locker1StartFromLocker2 got locker2StartFromLocker1 waiting for locker2StartFromLocker2 waiting for locker1