26 ms·

I am a bit confused, in another post you mentioned The C spec only requires that integer constant expressions that have zero value are nullptrs. The moment y

I am a bit confused, in another post you mentioned The C spec only requires that integer constant expressions that have zero value are nullptrs. The moment you assign it to an int variable, it's no longer a constant expression as far as the language is concerned, so if you then cast that int variable to a pointer, the result is indeterminate It is not an integer constant that gets assigned to a pointer so this is not a null pointer in that case? It is just a pointer with address of 0 (which very well might be the implementation of nullptr but from my understanding that is not required?) so shouldn't nullptr dereferencing rule not apply here?

int_19h 2y ago
Indeed, it's UB not because it's dereferencing a nullptr; it's UB because it's dereferencing an invalid pointer (i.e. a pointer that does not point to any C object). An implementation could declare that there is a valid object at address 0, I suppose, but strictly conforming code cannot rely on this. As far as I remember, the only ints you can cast to a pointer and then safely use are those that were cast from (valid) pointers in the first place.