<!-- GENERATED by docs/sphinx/bin/02-reference from Socket.rs (xs_pack_sockaddr_in6). Do not edit. -->

```{index} single: pack_sockaddr_in6; Socket function
```
```{index} single: Socket::pack_sockaddr_in6; Perl function
```

# pack_sockaddr_in6

Build a packed `sockaddr_in6` from a port, a 16-byte IPv6 address, and optional scope and flow-info fields.

## Synopsis

```perl
my $sin6 = pack_sockaddr_in6($port, $packed_ipv6);
my $sin6 = pack_sockaddr_in6($port, $packed_ipv6, $scope_id, $flowinfo);
```

## What you get back

A fixed-size byte string matching the platform's `struct
sockaddr_in6`, ready for `bind` or `connect`.

## Examples

```perl
my $addr = inet_pton(AF_INET6, "::1");
my $sin6 = pack_sockaddr_in6(443, $addr);
connect($sock, $sin6) or die $!;
```

```perl

## Link-local address with scope index for eth0.

my $scope = scalar getsockopt(...);   # or from if_nametoindex
my $sin6  = pack_sockaddr_in6(5353, inet_pton(AF_INET6, "fe80::1"), $scope);
```

## Edge cases

- `$scope_id` and `$flowinfo` default to 0 when omitted.
- An address argument shorter than 16 bytes leaves the address
  field zeroed (i.e. `::`).
- Port and flow-info are truncated to 16 and 32 bits respectively.

## Differences from upstream

Fully compatible with upstream Socket.

## See also

- `unpack_sockaddr_in6` — reverse direction.
- `sockaddr_in6` — dual-mode shortcut that dispatches on arg count.
- `pack_sockaddr_in` — IPv4 counterpart.
- `inet_pton` — usual source of the address argument.