Why AccessViolationException cannot be caught by .NET4.0

Question

It is really interesting that the following C# code will crash on .NET4.0 but work fine on .NET2.0.

C# code

class Program
{
    stat         


        

Answer 1

    [HandleProcessCorruptedStateExceptions]
    public static unsafe int LenghtPoint(this IntPtr point)
    {
        //por optimizar
        byte* bytePoint = (byte*)point.ToPointer();
        byte auxByte;
        int length = 1;
        bool encontrado = false;
        while (!encontrado)
        {

            try
            {

                auxByte = bytePoint[length];
                length++;
            }
            catch (System.AccessViolationException)
            {
                length--;
                encontrado = true;

            }
        }
        return length;
    }

Answer 2

Yes, it changed in .NET 4. You cannot catch exceptions that indicate a corrupted state. This is because there's pretty much no guarantee that you can do anything at all when a corrupted state exception is thrown. There is practically no reason to want a process with corrupted state to continue executing.

For compatibility with older code, you can change this behaviour by adding the legacyCorruptedStateExceptionsPolicy element to app.config.

You can also do it on a case-by-case basis by marking methods where you want to catch these exceptions with the HandleProcessCorruptedStateExceptions attribute.