C# string.GetHashCode() returns non int result

Question

One of my clients had an app crash and i traced it due to this bug/feature i can't really explain.
The WindowsIdentity.GetCurrent().Name.GetHashCode() returns this string: - ?2097695743
Yes, that a minus, a space, a question mark and then the actual hash numbers.

This is the code of a simple console app that show the weird behaviour.

static void Main(string[] args)
{
    Console.WriteLine("From String: string name = WindowsIdentity.GetCurrent().Name");            
    string name = WindowsIdentity.GetCurrent().Name;
    Console.WriteLine("name:                            " + name);
    Console.WriteLine("name.GetHashCode().GetType():    " + name.GetHashCode().GetType());
    Console.WriteLine("name.GetHashCode():              " + name.GetHashCode());
    Console.WriteLine("name.GetHashCode().ToString():   " + name.GetHashCode().ToString());
    Console.WriteLine();
    Console.WriteLine();
    Console.WriteLine("Direct");
    Console.WriteLine("WindowsIdentity.GetCurrent().Name:                           " + WindowsIdentity.GetCurrent().Name);
    Console.WriteLine("WindowsIdentity.GetCurrent().Name.GetHashCode().GetType():   " + WindowsIdentity.GetCurrent().Name.GetHashCode().GetType());
    Console.WriteLine("WindowsIdentity.GetCurrent().Name.GetHashCode():             " + WindowsIdentity.GetCurrent().Name.GetHashCode());
    Console.WriteLine("WindowsIdentity.GetCurrent().Name.GetHashCode().ToString():  " + WindowsIdentity.GetCurrent().Name.GetHashCode().ToString());
    Console.WriteLine();
    Console.WriteLine();
    Console.WriteLine("Press Enter to continue");
    Console.ReadLine();
}

This is the text output:

From String: string name = WindowsIdentity.GetCurrent().Name
name:                            COMMARC\tje
name.GetHashCode().GetType():    System.Int32
name.GetHashCode():              - ?2097695743
name.GetHashCode().ToString():   - ?2097695743

Direct
WindowsIdentity.GetCurrent().Name:                           COMMARC\tje
WindowsIdentity.GetCurrent().Name.GetHashCode().GetType():   System.Int32
WindowsIdentity.GetCurrent().Name.GetHashCode():             - ?2097695743
WindowsIdentity.GetCurrent().Name.GetHashCode().ToString():  - ?2097695743


Press Enter to continue

And this is a picture of the same output:

My question is: How on earth is this possible?

UPDATE: the problem was with the funky windows settings for negative numbers.

Answer 1

If that is the output on the client's computer (but not yours or ours), it's possible the user's machine has specifically configured windows to use "- ?" as the numeric negative symbol. Windows is perfectly willing to let you do that, or any other weird formats.

As a test, I just configured Windows on my machine to use "- ?", and running a simple console app like yours output goofy formatted negative numbers just like your example output. If that's the case on your client's machine, there is nothing wrong with the operation of GetHashCode, it's just an artifact of Windows formatting.