<!-- GENERATED by docs/sphinx/bin/20-reference (p5) from Socket.rs. Do not edit. -->


# Socket

<div class="pperl-badges"><span class="pperl-badge pperl-tier-std" title="Minimum feature tier: std. Available in all builds from \`--features native-std\` upward.">📦 std</span></div>

BSD socket constants and address pack/unpack helpers that feed Perl’s
built-in `socket`, `bind`, `connect`, `accept`, `send`, `recv`,
`setsockopt`, and `shutdown`.

Typical flow: import a constant, pack it into a sockaddr, hand the
result to the built-in.

```perl
use Socket;
socket(my $sock, PF_INET, SOCK_STREAM, IPPROTO_TCP) or die $!;
my $addr = pack_sockaddr_in(80, inet_aton("127.0.0.1"));
connect($sock, $addr) or die $!;
```

## What lives here

- **Address families**: `AF_INET`, `AF_INET6`, `AF_UNIX`, `AF_LOCAL`,
  `AF_UNSPEC`, plus the matching `PF_*` protocol families.
- **Socket types**: `SOCK_STREAM`, `SOCK_DGRAM`, `SOCK_RAW`,
  `SOCK_SEQPACKET`.
- **Well-known addresses**: `INADDR_ANY`, `INADDR_LOOPBACK`,
  `INADDR_BROADCAST`, `INADDR_NONE`, `IN6ADDR_ANY`, `IN6ADDR_LOOPBACK`
  (packed binary, ready for `pack_sockaddr_in` / `pack_sockaddr_in6`).
- **Protocol numbers**: `IPPROTO_IP`, `IPPROTO_TCP`, `IPPROTO_UDP`,
  `IPPROTO_IPV6`, `IPPROTO_ICMP`, `IPPROTO_RAW`.
- **Socket-option levels and names**: `SOL_SOCKET`, `SO_REUSEADDR`,
  `SO_KEEPALIVE`, `SO_BROADCAST`, `SO_LINGER`, `SO_SNDBUF`, `SO_RCVBUF`,
  `SO_ERROR`, `SO_TYPE`, and the rest of the `SO_*` family.
- **TCP options**: `TCP_NODELAY`.
- **IP options**: `IP_TOS`, `IP_TTL`, `IP_MULTICAST_TTL`,
  `IP_MULTICAST_LOOP`, `IP_ADD_MEMBERSHIP`, `IP_DROP_MEMBERSHIP`,
  plus the `IPV6_*` counterparts.
- **Message flags**: `MSG_OOB`, `MSG_PEEK`, `MSG_DONTWAIT`,
  `MSG_WAITALL`, `MSG_NOSIGNAL`.
- **Shutdown modes**: `SHUT_RD`, `SHUT_WR`, `SHUT_RDWR`.
- **Address packing**: `pack_sockaddr_in`, `unpack_sockaddr_in`,
  `pack_sockaddr_in6`, `unpack_sockaddr_in6`, `pack_sockaddr_un`,
  `unpack_sockaddr_un`, plus the dual-mode `sockaddr_in` /
  `sockaddr_in6` shortcuts and the `sockaddr_family` extractor.
- **Address parsing**: `inet_aton`, `inet_ntoa`, `inet_pton`,
  `inet_ntop`.
- **Name resolution**: `getaddrinfo`, `getnameinfo`, plus the
  `AI_*`, `NI_*`, and `EAI_*` flag and error constants.

## Functions

### Address packing

#### [`pack_sockaddr_in`](Socket/pack_sockaddr_in.md)

Build a packed `sockaddr_in` from a port number and a 4-byte IPv4 address, ready to hand to `bind` or `connect`.

#### [`unpack_sockaddr_in`](Socket/unpack_sockaddr_in.md)

Split a packed `sockaddr_in` back into its port and 4-byte address.

#### [`pack_sockaddr_in6`](Socket/pack_sockaddr_in6.md)

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

#### [`unpack_sockaddr_in6`](Socket/unpack_sockaddr_in6.md)

Split a packed `sockaddr_in6` into port, 16-byte address, scope id, and flow-info.

#### [`pack_sockaddr_un`](Socket/pack_sockaddr_un.md)

Build a packed `sockaddr_un` from a filesystem path, for use with Unix-domain sockets.

#### [`unpack_sockaddr_un`](Socket/unpack_sockaddr_un.md)

Extract the filesystem path from a packed `sockaddr_un`.

#### [`sockaddr_family`](Socket/sockaddr_family.md)

Read the address-family byte from any packed sockaddr without committing to one unpacking shape.

#### [`sockaddr_in`](Socket/sockaddr_in.md)

Dual-mode shortcut: with two arguments it behaves like `pack_sockaddr_in`; with one argument it behaves like `unpack_sockaddr_in`.

#### [`sockaddr_in6`](Socket/sockaddr_in6.md)

Dual-mode IPv6 shortcut: with two or more arguments it behaves like `pack_sockaddr_in6`; with a single argument it behaves like `unpack_sockaddr_in6`.

### Address parsing

#### [`inet_aton`](Socket/inet_aton.md)

Turn a dotted-quad string or a hostname into a 4-byte packed IPv4 address, or `undef` if the name cannot be resolved.

#### [`inet_ntoa`](Socket/inet_ntoa.md)

Turn a 4-byte packed IPv4 address back into a dotted-quad string.

#### [`inet_pton`](Socket/inet_pton.md)

Parse an address string into its packed binary form for either IPv4 or IPv6, selected by the first argument.

#### [`inet_ntop`](Socket/inet_ntop.md)

Turn a packed IPv4 or IPv6 address back into its printable string form, selected by the first argument.

### Name resolution

#### [`getaddrinfo`](Socket/getaddrinfo.md)

Resolve a host name and/or service name into a list of ready-to-use address records, honouring IPv4/IPv6 and protocol preferences carried through a hints hash.

#### [`getnameinfo`](Socket/getnameinfo.md)

Turn a packed sockaddr into a host name and service name, with optional flags to force numeric output or demand a successful DNS lookup.