scan_ip6if man page
scan_ip6 — parse an IPv6 number and interface in ASCII representation
int scan_ip6if(const char *src,char ip,uint32* scope_id);
scan_ip6if parses an IPv6 number in RFC1884 ASCII representation from src and writes the result into ip. If the IPv6 number is followed by the percent sign, scan_ip6if takes the word following that, tries to parse it as network interface and writes the result to scope_id.
It returns the number of bytes read from src or 0 if the parsing failed.
scan_ip6if accepts upper and lower case hex letters, it understands "::" compression and partial IPv4 addresses as in "::FFFF:22.214.171.124".
To allow transparent usage of IPv4 in IPv6 applications, scan_ip6if also understands IPv4 addresses in dotted-decimal notation and will return an IPv4-mapped IPv6 address (i.e. "127.0.0.1" will be parsed as "::FFFF:127.0.0.1".
Unlike many other IP parsing routines, scan_ip6if does not recognize octal (like 0126.96.36.199) or hexadecimal numbers (like 0x7f000001) in the IPv4 part.
if (scan_ip6if(buf,ip,&scope_id) != str_len(buf))
fmt_ip6(3), scan_ip4(3), fmt_ip6if(3)