IO::Socket::UNIX(3p) Perl Programmers Reference Guide IO::Socket::UNIX(3p)

IO::Socket::UNIX - Object interface for AF_UNIX domain sockets

    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

"IO::Socket::UNIX" provides an object interface to creating and using sockets in the AF_UNIX domain. It is built upon the IO::Socket interface and inherits all the methods defined by IO::Socket.

Creates an "IO::Socket::UNIX" object, which is a reference to a newly created symbol (see the "Symbol" package). "new" optionally takes arguments, these arguments are in key-value pairs.

In addition to the key-value pairs accepted by IO::Socket, "IO::Socket::UNIX" provides.

    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 the constructor is only passed a single argument, it is assumed to be a "Peer" specification.

If the "Listen" argument is given, but false, the queue size will be set to 5.

If the constructor fails it will return "undef" and set 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 here instead.

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

Returns the pathname to the fifo at the local end
Returns the pathanme to the fifo at the peer end

Socket, IO::Socket

Graham Barr. Currently maintained by the Perl Porters. Please report all bugs at <>.

Copyright (c) 1996-8 Graham Barr <>. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

2023-02-15 perl v5.36.3