#### ip::address_v4::netmask

(Deprecated: Use `ip::network_v4` class.) Obtain the netmask that corresponds to the address, based on its address class.

    static address_v4 netmask(
        const address_v4 & addr);

| Copyright © 2003-2020 Christopher M. Kohlhoff Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)