memcpy(change.addr, addr, sizeof(change.addr));
memcpy(change.netmask, netmask, sizeof(change.netmask));
n = os_write_file(fd, &change, sizeof(change));
memcpy(change.addr, addr, sizeof(change.addr));
memcpy(change.netmask, netmask, sizeof(change.netmask));
n = os_write_file(fd, &change, sizeof(change));