Why doesn't the OS crash if I dereference a null pointer?

Question

Dereferencing a null pointer results in undefined behavior. In practice it usually means that my program will crash. But why doesn\'t the OS crash? Because if my progra

Answer 1

Sorry, what rules of 'logical transitivity'? One of the things an operating system is designed to do is to protect programs from the misbehaviour of other programs. In particular, the O/S should not crash just because your program tries to do something silly.

On operating systems without memory protection, accessing via a null (or any invalid) pointer could indeed cause the O/S to crash (if the O/S happened to use location 0 for something interesting).

But that has nothing to do with logical transitivity. That has to do with your program accessing memory that belongs to another program. Either programs could crash in those circumstances.