Bitwise XOR the value of the specified rhs array with the value of this array (retaining the results), and return a non-const reference to this object. If length() > rhs.length(), the unmatched most-significant bits in this array are left unchanged; otherwise, any unmatched most-significant bits in rhs are propagated to the result without modification. Note that a ^= b; will result in the same value of a as a = a ^ b;.