C++ keyword: and_eq - cppreference.com From cppreference.com Usage alternative operators: as an alternative for &= Example #include <bitset> #include <iostream> int main() { std::bitset<4> mask("1100"); std::bitset<4> val("0111"); val and_eq mask; std::cout << val << '\n'; } Output: See also and bitand, bitor not, not_eq or, or_eq xor, xor_eq