IO::SOCKET::UNIX(3perl)

💖 IO::Socket::UNIX — bestie edition 💖

okay so you found the IO::Socket::UNIX page, which lives in the perl manual, section 3perl, of the Perl Programmers Reference Guide. it's about AF_UNIX domain sockets and it's honestly iconic. let's go 🦋

---

✨ NAME ✨

IO::Socket::UNIX — object interface for AF_UNIX domain sockets 💅

---

🌸 SYNOPSIS 🌸

use IO::Socket::UNIX;

my $SOCK_PATH = "$ENV{HOME}/unix-domain-socket-test.sock";

# Server:
my $server = IO::Socket::UNIX->new(
    Type => SOCK_STREAM(),
    Local => $SOCK_PATH,
    Listen => 1,
);

my $count = 1;
while (my $conn = $server->accept()) {
    $conn->print("Hello " . ($count++) . "\n");
}

# Client:
my $client = IO::Socket::UNIX->new(
    Type => SOCK_STREAM(),
    Peer => $SOCK_PATH,
);

# Now read and write from $client

like… a whole server AND a whole client in one code block?? we love a two-for-one 🫶

---

🎀 DESCRIPTION 🎀

so basically, IO::Socket::UNIX hands you an object interface for creating and using sockets in the AF_UNIX domain. it's built on top of the IO::Socket interface, and it inherits every single method that IO::Socket defines. no cap. 👑

---

💅 CONSTRUCTOR 💅

new ( [ARGS] )

creates an IO::Socket::UNIX object, which is a reference to a newly created symbol (peep the Symbol package for that). new optionally takes arguments, and those arguments come in key-value pairs.

on top of the key-value pairs that IO::Socket already accepts, IO::Socket::UNIX brings its own little set:

• Type — Type of socket (eg SOCK_STREAM or SOCK_DGRAM)
• Local — Path to local fifo
• Peer — Path to peer fifo
• Listen — Queue size for listen

if you pass the constructor only a single argument, it gets assumed to be a Peer specification. that's the vibe check right there ✨

if the Listen argument is given, but it's false, then the queue size gets set to 5. noted. 📝

if the constructor fails, it returns undef and sets the $IO::Socket::errstr package variable to contain an error message.

$sock = IO::Socket::UNIX->new(...)
    or die "Cannot create socket - $IO::Socket::errstr\n";

for legacy reasons the error message is also set into the global $@ variable, and you may still find older code which looks there instead. ancient. historical. still real.

$sock = IO::Socket::UNIX->new(...)
    or die "Cannot create socket - $@\n";

---

🧚 METHODS 🧚

• hostpath() — Returns the pathname to the fifo at the local end
• peerpath() — Returns the pathname to the fifo at the peer end

two methods, both serving exactly. periodt. 🔥

---

🌈 SEE ALSO 🌈

• Socket
• IO::Socket

---

👑 AUTHOR 👑

Graham Barr. Currently maintained by the Perl Porters. Please report all bugs at https://github.com/Perl/perl5/issues. 🐛

---

💜 COPYRIGHT 💜

Copyright (c) 1996-8 Graham Barr gbarr@pobox.com. All rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

---

okay that's the whole page bestie, go make some sockets 🍓

and for the sign-off — this was perl v5.44.0, dated 2026-10-17, page IO::Socket::UNIX(3perl). slay, stay hydrated, and close your file descriptors 💖✨