--- name: "IO::Socket" section: "3pm" platform: "linux" package: "perl-5.004-doc" version: "5.004.05-6" release: "Debian 2.2 (Potato)" platforms: ["linux"] url: "https://new.carta.tech/IO::Socket/3pm" --- # IO::Socket(3pm) IO::Socket - Object interface to socket communications ``` use IO::Socket; ``` `IO::Socket` provides an object interface to creating and using sockets. It is built upon the the *IO::Handle* manpage interface and inherits all the methods defined by the *IO::Handle* manpage. `IO::Socket` only defines methods for those operations which are common to all types of socket. Operations which are specified to a socket in a particular domain have methods defined in sub classes of `IO::Socket` `IO::Socket` will export all functions (and constants) defined by the *Socket* manpage.\ Creates an `IO::Socket`, which is a reference to a newly created symbol (see the `Symbol` package). `new` optionally takes arguments, these arguments are in key-value pairs. `new` only looks for one key `Domain` which tells new which domain the socket will be in. All other arguments will be passed to the configuration method of the package for that domain, See below. `IO::Socket`s will be in autoflush mode after creation. Note that versions of IO::Socket prior to 1.1603 (as shipped with Perl 5.004\_04) did not do this. So if you need backward compatibility, you should set autoflush explicitly. See the *perlfunc* manpage for complete descriptions of each of the following supported `IO::Socket` methods, which are just front ends for the corresponding built-in functions: ``` socket socketpair bind listen accept send recv peername (getpeername) sockname (getsockname) ``` Some methods take slightly different arguments to those defined in the *perlfunc* manpage in attempt to make the interface more flexible. These are\ perform the system call `accept` on the socket and return a new object. The new object will be created in the same class as the listen socket, unless `PKG` is specified. This object can be used to communicate with the client that was trying to connect. In a scalar context the new socket is returned, or undef upon failure. In an array context a two-element array is returned containing the new socket and the peer address, the list will be empty upon failure. Additional methods that are provided are\ Set or get the timeout value associated with this socket. If called without any arguments then the current setting is returned. If called with an argument the current setting is changed and the previous value returned.\ Unified method to both set and get options in the SOL\_SOCKET level. If called with one argument then getsockopt is called, otherwise setsockopt is called.\ Returns the numerical number for the socket domain type. For example, for a AF\_INET socket the value of &AF\_INET will be returned.\ Returns the numerical number for the socket type. For example, for a SOCK\_STREAM socket the value of &SOCK\_STREAM will be returned.\ Returns the numerical number for the protocol being used on the socket, if known. If the protocol is unknown, as with an AF\_UNIX socket, zero is returned.\ **IO::Socket::INET** `IO::Socket::INET` provides a constructor to create an AF\_INET domain socket and some related methods. The constructor can take the following options ``` PeerAddr Remote host address [:] PeerPort Remote port or service [()] ⎪ LocalAddr Local host bind address hostname[:port] LocalPort Local host bind port [()] ⎪ Proto Protocol name (or number) "tcp" ⎪ "udp" ⎪ ... Type Socket type SOCK_STREAM ⎪ SOCK_DGRAM ⎪ ... Listen Queue size for listen Reuse Set SO_REUSEADDR before binding Timeout Timeout value for various operations ``` If `Listen` is defined then a listen socket is created, else if the socket type, which is derived from the protocol, is SOCK\_STREAM then *connect()* is called. The `PeerAddr` can be a hostname or the IP-address on the "xx.xx.xx.xx" form. The `PeerPort` can be a number or a symbolic service name. The service name might be followed by a number in parenthesis which is used if the service is not known by the system. The `PeerPort` specification can also be embedded in the `PeerAddr` by preceding it with a ":". If `Proto` is not given and you specify a symbolic `PeerPort` port, then the constructor will try to derive `Proto` from the service name. As a last resort `Proto` "tcp" is assumed. The `Type` parameter will be deduced from `Proto` if not specified. If the constructor is only passed a single argument, it is assumed to be a `PeerAddr` specification. Examples: ``` $sock = IO::Socket::INET->new(PeerAddr => 'www.perl.org', PeerPort => 'http(80)', Proto => 'tcp'); ``` ``` $sock = IO::Socket::INET->new(PeerAddr => 'localhost:smtp(25)'); ``` ``` $sock = IO::Socket::INET->new(Listen => 5, LocalAddr => 'localhost', LocalPort => 9000, Proto => 'tcp'); ``` ``` $sock = IO::Socket::INET->new('127.0.0.1:25'); ``` **METHODS**\ Return the address part of the sockaddr structure for the socket\ Return the port number that the socket is using on the local host\ Return the address part of the sockaddr structure for the socket in a text form xx.xx.xx.xx\ Return the address part of the sockaddr structure for the socket on the peer host\ Return the port number for the socket on the peer host.\ Return the address part of the sockaddr structure for the socket on the peer host in a text form xx.xx.xx.xx\ **IO::Socket::UNIX** `IO::Socket::UNIX` provides a constructor to create an AF\_UNIX domain socket and some related methods. The constructor can take the following options ``` Type Type of socket (eg SOCK_STREAM or SOCK_DGRAM) Local Path to local fifo Peer Path to peer fifo Listen Create a listen socket ``` **METHODS**\ Returns the pathname to the fifo at the local end\ Returns the pathanme to the fifo at the peer end the *Socket* manpage, the *IO::Handle* manpage Graham Barr \<*Graham.Barr@tiuk.ti.com*\> Copyright (c) 1996 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.