ID0write
if (ID0write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0 &&
extern int ID0write(int, const void *, size_t);
wb = ID0write(s, &rtmes, nb);
if ((wb = ID0write(s, &rtmes, nb)) < 0)
wb = ID0write(s, &rtmes, rtmes.m_rtm.rtm_msglen);