.net: Is assigning an object reference atomic (i.e. thread-safe)?

Question

Let's say I have some variable x (of type myClass), which is initially null and some assignment

x = myObject

occuring exactly once in some background thread.

Is it guaranteed that x always contains either null or myObject when accessed from the main thread? Or is it possible that x contains some invalid data shortly?

Answer 1

Provided the size of the type reference is the same size as the native word size of the CPU, then the assignment will be atomic (and safe in your described scenario).

In fact, (don't have the reference to hand) I'm fairly certain that a type ref will always be the same size as the native CPU word size.

Answer 2

From this (although it deals with somewhat different topic) I conclude that assignments are atomc.