C# default value of a pointer type

Question

I have been searching through the C# language spec and I can't find anything which says whether a pointer type (e.g. int*) gets initialized with a default value. I created a simple test app and it appears to initialize them to zero but I'd like to confirm this with the spec.

I started looking for this because I noticed in reflector the IntPtr class uses this code to define its IntPtr.Zero:

public struct IntPtr : ISerializable
{
   private unsafe void* m_value;
   public static readonly IntPtr Zero;

   .......

   public static unsafe bool operator ==(IntPtr value1, IntPtr value2)
   {
       return (value1.m_value == value2.m_value);
   }

   ........
}

which means that when you compare against IntPtr.Zero it actually is comparing against the default value assigned to the m_value field which has type void*.

Thanks.

Answer 1

I believe pointers have no default value; due to a pointer's value being the address of a portion of memory containing something you assign it to. If you haven't assigned it, it could be pointing to anything in memory.

Perhaps the CLR's default behavior is to set it to IntPtr.Zero, which "represents a pointer or handle that has been initialized to zero", which looks to be likely from Carmelo Floridia's answer. This seems to be an implementation detail which the spec may not have elaborated upon.