icmp6_errmap
int icmp6_errmap(const struct icmp6_hdr *);
errno = icmp6_errmap(icmp6);
if ((errno = icmp6_errmap(ip6cp->ip6c_icmp6)) != 0)
if (icmp6_errmap(ip6cp->ip6c_icmp6) == 0) {
if ((errno = icmp6_errmap(ip6cp->ip6c_icmp6)) == 0)