NULL and nullptr comparison

Question

Is it safe to compare pointers where one is NULL and other is nullptr? Will that comparison always give true?

Answer 1

Yes.

Both NULL and nullptr are "null pointer constants" and

A null pointer constant can be converted to a pointer type; the result is the null pointer value of that type and is distinguishable from every other value of object pointer or function pointer type.

Lastly,

Two null pointer values of the same type shall compare equal.

(Both quotes 4.10/1 in N4140)

Answer 2

Assuming that NULL is 0 (either through a #define or an integral type definition) then, yes.