Bitwise AND 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. The length of the result will be the maximum of the lengths of this object and rhs, where any most-significant bits that are represented in one of the two but not the other will be set to 0. Note that a &= b; will result in the same value of a as a = a & b;.