What is a canonical way to produce a segmentation fault in C#?

Question

I am interested in the shortest, neatest piece of C# code around that will reliably produce a segfault - ideally without directly calling any unmanaged code.

Answer 1

Compile with csc with the /unsafe option:

class Program
{
    static void Main(string[] args)
    {
        unsafe
        {
            int *p = null;
            *p = 5;
        }
    }
}

Answer 2

As noted in the comments above, there's no such thing as a segfault in Windows, and you didn't say anything about mono on Linux. So I'm going to assume you actually meant an access violation.

Here's a way to get one:

unsafe {
    int* a = (int*) -4;
    *a = 0;
}

(Must be compiled with the /unsafe option.)

My first try used 0 as the address, but that turned out to throw a plain old NullReferenceException, which you can get without unsafe code. But the negative address gets an AccessViolationException on my Vista x64 box.

Answer 3

What you're after is somewhat unclear but I suppose this is as good as any answer so far, and it is about as minimal as you can get.

System.Runtime.InteropServices.Marshal.ReadInt32(IntPtr.Zero);