C# volatile array items?

Question

I need an array with volatile items, and can't find a way to do that.

private volatile T[] _arr;

This means that the _arr reference is volatile, however it does not guarantee anything about the items inside the _arr object itself.

Is there any way to mark the _arr's Items as volatile?

Thanks.

EDIT:

The following code built according to binarycoder's answer. Is this code thread-safe to use?

public class VolatileArray<T>
{
    private T[] _arr;

    public VolatileArray(int length)
    {
        _arr = new T[length];
    }

    public VolatileArray(T[] arr)
    {
        _arr = arr;
    }

    public T this[int index]
    {
        get
        {
            T value = _arr[index];
            Thread.MemoryBarrier();
            return value;
        }

        set
        {
            Thread.MemoryBarrier();
            _arr[index] = value;
        }
    }

    public int Length
    {
        get { return _arr.Length; }
    }
}

Answer 1

Since it is possible to pass array elements by reference, you can use Thread.VolatileRead and Thread.VolatileWrite .

It is useful to understand that the volatile keyword works behind the scenes by using Thread.MemoryBarrier . You could write:

// Read
x = _arr[i];
Thread.MemoryBarrier();

// Write
Thread.MemoryBarrier();
_arr[i] = x;

Note that volatile and MemoryBarrier are advanced techniques that are both easy to get wrong. For example, see How do I Understand Read Memory Barriers and Volatile . Usually you are better off with higher level constructs such as lock , Monitor , ReaderWriterLockSlim , and others.

Answer 2

Use Volatile.Read(ref array[index]) and Volatile.Write(ref array[index], value) .

Class Volatile is available since .NET 4.5. It allows to read/write from/to fields, array elements, ref parameters, pointers.

Answer 3

I made a little struct that helps keep things clean and OO

struct VolatileBoolean {
    public volatile Boolean Value;
}

VolatileBoolean[] arrayOfVolatileBooleans;
public void SomeMethod() {
    if (arrayOfVolatileBooleans[4].Value)
        DoSomething();
}

Answer 4

I don't think that you can

You can't, volatile is defined as a field-modifier (ECMA 334).

And I don't think it will accomplish what you want either.
Consider:

 private T[] _arr;

 volatile T v;
 ....  v = _arr[x];
 ....  _arr[x] = v;