


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


NAME
       IO::Socket - Object interface to socket communications

SYNOPSIS
           use IO::Socket;

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

       "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 Socket.

CONSTRUCTOR
       new ( [ARGS] )
           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.

            NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE

           As of VERSION 1.18 all IO::Socket objects have
           autoflush turned on by default. This was not the case
           with earlier releases.

            NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE

METHODS
       See perlfunc 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)
           shutdown




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


       Some methods take slightly different arguments to those
       defined in perlfunc in attempt to make the interface more
       flexible. These are

       accept([PKG])
           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 a list context a two-element
           array is returned containing the new socket and the
           peer address; the list will be empty upon failure.

           The timeout in the [PKG] can be specified as zero to
           effect a "poll", but you shouldn't do that because a
           new IO::Select object will be created behind the
           scenes just to do the single poll.  This is
           horrendously inefficient.  Use rather true select()
           with a zero timeout on the handle, or non-blocking IO.

       socketpair(DOMAIN, TYPE, PROTOCOL)
           Call "socketpair" and return a list of two sockets
           created, or an empty list on failure.

       Additional methods that are provided are:

       atmark
           True if the socket is currently positioned at the
           urgent data mark, false otherwise.

               use IO::Socket;

               my $sock = IO::Socket::INET->new('some_server');
               $sock->read($data, 1024) until $sock->atmark;

           Note: this is a reasonably new addition to the family
           of socket functions, so all systems may not support
           this yet.  If it is unsupported by the system, an
           attempt to use this method will abort the program.

           The atmark() functionality is also exportable as
           sockatmark() function:

                   use IO::Socket 'sockatmark';

           This allows for a more traditional use of sockatmark()
           as a procedural socket function.  If your system does
           not support sockatmark(), the "use" declaration will
           fail at compile time.





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


       connected
           If the socket is in a connected state the peer address
           is returned.  If the socket is not in a connected
           state then undef will be returned.

       protocol
           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.

       sockdomain
           Returns the numerical number for the socket domain
           type. For example, for an AF_INET socket the value of
           &AF_INET will be returned.

       sockopt(OPT [, VAL])
           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.

       socktype
           Returns the numerical number for the socket type. For
           example, for a SOCK_STREAM socket the value of
           &SOCK_STREAM will be returned.

       timeout([VAL])
           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.

SEE ALSO
       Socket, IO::Handle, IO::Socket::INET, IO::Socket::UNIX

AUTHOR
       Graham Barr.  atmark() by Lincoln Stein.  Currently
       maintained by the Perl Porters.  Please report all bugs to
       <perl5-porters@perl.org>.

COPYRIGHT
       Copyright (c) 1997-8 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.

       The atmark() implementation: Copyright 2001, Lincoln Stein
       <lstein@cshl.org>.  This module is distributed under the
       same terms as Perl itself.  Feel free to use, modify and
       redistribute it as long as you retain the correct
       attribution.






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