interlocked.cs

using NUnit.Framework;
using System.Threading;
using System;

public class Test {
	public static void CompareExchange_Generic ()
	{
		object a = null;
		Assert.IsNull (Interlocked.CompareExchange<object> (ref a, a, a), "null,null,null");
		/*
		object b = new object ();
		Assert.IsNull (Interlocked.CompareExchange<object> (ref a, a, b), "null,non-null,non-null");
		Assert.IsNull (Interlocked.CompareExchange<object> (ref a, b, a), "null,non-null,null");
		Assert.AreSame (b, Interlocked.CompareExchange<object> (ref a, b, b), "null,null,non-null");

		Assert.AreSame (b, Interlocked.CompareExchange<object> (ref b, a, a), "non-null,null,null");
		Assert.AreSame (b, Interlocked.CompareExchange<object> (ref b, a, b), "non-null,null,non-null");
		Assert.AreSame (b, Interlocked.CompareExchange<object> (ref b, b, a), "non-null,non-null,null");
		Assert.AreSame (b, Interlocked.CompareExchange<object> (ref b, b, b), "non-null,non-null,non-null");
		*/
	}

	public static object Null2 (int i) {
		if (i == 0)
			return null;
		return Null2 (i - 1);
	}

	/* force non-inline */
	public static object Null () {
		return Null2 (123);
	}

	public static bool Correctness () {
		object a = "abc";
		object b = a;
		object c = Null ();
		Interlocked.CompareExchange<object> (ref a, b, c);
		if (c != null) {
			Console.WriteLine ("error");
			return false;
		}
		return true;
	}

	public static object Ident (object x) {
		return x;
	}

	public static void Dummy (object a, object b, object c) {
	}

	public static object Crash () {
		object a = "abc";
		object b = Ident (a);
		object c = Null ();
		object d = Interlocked.CompareExchange<object> (ref a, b, c);
		a = Interlocked.CompareExchange<object> (ref b, c, d);
		b = Interlocked.CompareExchange<object> (ref c, d, a);
		c = Interlocked.CompareExchange<object> (ref d, a, b);
		return c;
	}

	public static int Main () {
		CompareExchange_Generic ();
		//if (!Correctness ())
		//return 1;
		//Crash ();

		/*
		object a = null;
		Interlocked.CompareExchange<object> (ref a, a, a);
		object b = new object ();
		Interlocked.CompareExchange<object> (ref a, a, b);
		Interlocked.CompareExchange<object> (ref a, b, a);
		Interlocked.CompareExchange<object> (ref a, b, b);

		Interlocked.CompareExchange<object> (ref b, a, a);
		Interlocked.CompareExchange<object> (ref b, a, b);
		Interlocked.CompareExchange<object> (ref b, b, a);
		Interlocked.CompareExchange<object> (ref b, b, b);
		*/


		return 0;
	}
}