Thread Safety

gistfile1.cs

for (int i = 0; i < 100; i++)
            {
                ManualResetEvent allGo = new ManualResetEvent(false);
                var model = new MyClass();
                object starter = new object();
                int waiting = 20;
                int failures = 0;
                Exception firstException = null;
                Thread[] threads = new Thread[20];
                for (int j = 0; j < 10; j++)
                {
                    threads[2 * j] = new Thread(() =>
                    {
                        try
                        {
                            if (Interlocked.Decrement(ref waiting) == 0) allGo.Set();
                            allGo.WaitOne();
                            model.Add(i.ToString());
                        }
                        catch (Exception ex)
                        {
                            Interlocked.CompareExchange(ref firstException, ex, null);
                            Interlocked.Increment(ref failures);
                        }
                    });
                    threads[(2 * j) + 1] = new Thread(() =>
                    {
                        try
                        {
                            if (Interlocked.Decrement(ref waiting) == 0) allGo.Set();
                            allGo.WaitOne();
                            model.Add(i.ToString());
                        }
                        catch (Exception ex)
                        {
                            Interlocked.CompareExchange(ref firstException, ex, null);
                            Interlocked.Increment(ref failures);
                        }
                    });
                }

                for (int j = 0; j < threads.Length; j++) threads[j].Start();
                for (int j = 0; j < threads.Length; j++) threads[j].Join();

                Assert.IsNull(firstException);
                Assert.AreEqual(0, Interlocked.CompareExchange(ref failures, 0, 0));

            }
        }