扩展一个IPv6地址，以便我可以将其打印到stdout

扩展一个IPv6地址，以便我可以将其打印到stdout

void ipv6_to_str_unexpanded(char * str, const struct in6_addr * addr) {   sprintf(str, "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x",      (int)addr->s6_addr[0], (int)addr->s6_addr[1],      (int)addr->s6_addr[2], (int)addr->s6_addr[3],      (int)addr->s6_addr[4], (int)addr->s6_addr[5],      (int)addr->s6_addr[6], (int)addr->s6_addr[7],      (int)addr->s6_addr[8], (int)addr->s6_addr[9],      (int)addr->s6_addr[10], (int)addr->s6_addr[11],      (int)addr->s6_addr[12], (int)addr->s6_addr[13],      (int)addr->s6_addr[14], (int)addr->s6_addr[15]);}