Null reference for first memory address between 0 - 65535

Question

I would like to understand a bit more about memory and I was unable to find it from Google, please forgive me if this is silly question.

How come the following code, accessing memory address 0(and up to 65535) in C# would throw NullReferenceException

byte* pointer = (byte*)0;

byte test = *pointer;

Thanks a lot in advance!

Answer 1

This is a design feature of Windows itself. In order to catch programmer mistakes early in the development cycle, the virtual addresses from 0 to 64K (- 1) are invalid in all processes.