1IO::Socket(3pm) Perl Programmers Reference Guide IO::Socket(3pm)
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6 IO::Socket - Object interface to socket communications
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9 use IO::Socket;
10
12 "IO::Socket" provides an object interface to creating and using sock‐
13 ets. It is built upon the IO::Handle interface and inherits all the
14 methods defined by IO::Handle.
15 "IO::Socket" only defines methods for those operations which are common
17 to all types of socket. Operations which are specified to a socket in a
18 particular domain have methods defined in sub classes of "IO::Socket"
19 "IO::Socket" will export all functions (and constants) defined by
21 Socket.
22
24 new ( [ARGS] )
25 Creates an "IO::Socket", which is a reference to a newly created
26 symbol (see the "Symbol" package). "new" optionally takes argu‐
27 ments, these arguments are in key-value pairs. "new" only looks
28 for one key "Domain" which tells new which domain the socket will
29 be in. All other arguments will be passed to the configuration
30 method of the package for that domain, See below.
31 NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE
33 As of VERSION 1.18 all IO::Socket objects have autoflush turned on
35 by default. This was not the case with earlier releases.
36 NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE
38
40 See perlfunc for complete descriptions of each of the following sup‐
41 ported "IO::Socket" methods, which are just front ends for the corre‐
42 sponding built-in functions:
43 socket
45 socketpair
46 bind
47 listen
48 accept
49 send
50 recv
51 peername (getpeername)
52 sockname (getsockname)
53 shutdown
54 Some methods take slightly different arguments to those defined in
56 perlfunc in attempt to make the interface more flexible. These are
57 accept([PKG])
59 perform the system call "accept" on the socket and return a new
60 object. The new object will be created in the same class as the
61 listen socket, unless "PKG" is specified. This object can be used
62 to communicate with the client that was trying to connect.
63 In a scalar context the new socket is returned, or undef upon fail‐
65 ure. In a list context a two-element array is returned containing
66 the new socket and the peer address; the list will be empty upon
67 failure.
68 The timeout in the [PKG] can be specified as zero to effect a
70 "poll", but you shouldn't do that because a new IO::Select object
71 will be created behind the scenes just to do the single poll. This
72 is horrendously inefficient. Use rather true select() with a zero
73 timeout on the handle, or non-blocking IO.
74 socketpair(DOMAIN, TYPE, PROTOCOL)
76 Call "socketpair" and return a list of two sockets created, or an
77 empty list on failure.
78 Additional methods that are provided are:
80 atmark
82 True if the socket is currently positioned at the urgent data mark,
83 false otherwise.
84 use IO::Socket;
86 my $sock = IO::Socket::INET->new('some_server');
88 $sock->read($data, 1024) until $sock->atmark;
89 Note: this is a reasonably new addition to the family of socket
91 functions, so all systems may not support this yet. If it is
92 unsupported by the system, an attempt to use this method will abort
93 the program.
94 The atmark() functionality is also exportable as sockatmark() func‐
96 tion:
97 use IO::Socket 'sockatmark';
99 This allows for a more traditional use of sockatmark() as a proce‐
101 dural socket function. If your system does not support sockat‐
102 mark(), the "use" declaration will fail at compile time.
103 connected
105 If the socket is in a connected state the peer address is returned.
106 If the socket is not in a connected state then undef will be
107 returned.
108 protocol
110 Returns the numerical number for the protocol being used on the
111 socket, if known. If the protocol is unknown, as with an AF_UNIX
112 socket, zero is returned.
113 sockdomain
115 Returns the numerical number for the socket domain type. For exam‐
116 ple, for an AF_INET socket the value of &AF_INET will be returned.
117 sockopt(OPT [, VAL])
119 Unified method to both set and get options in the SOL_SOCKET level.
120 If called with one argument then getsockopt is called, otherwise
121 setsockopt is called.
122 socktype
124 Returns the numerical number for the socket type. For example, for
125 a SOCK_STREAM socket the value of &SOCK_STREAM will be returned.
126 timeout([VAL])
128 Set or get the timeout value associated with this socket. If called
129 without any arguments then the current setting is returned. If
130 called with an argument the current setting is changed and the pre‐
131 vious value returned.
132
134 Socket, IO::Handle, IO::Socket::INET, IO::Socket::UNIX
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137 Graham Barr. atmark() by Lincoln Stein. Currently maintained by the
138 Perl Porters. Please report all bugs to <perl5-porters@perl.org>.
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141 Copyright (c) 1997-8 Graham Barr <gbarr@pobox.com>. All rights
142 reserved. This program is free software; you can redistribute it
143 and/or modify it under the same terms as Perl itself.
144 The atmark() implementation: Copyright 2001, Lincoln Stein
146 <lstein@cshl.org>. This module is distributed under the same terms as
147 Perl itself. Feel free to use, modify and redistribute it as long as
148 you retain the correct attribution.
149perl v5.8.8 2001-09-21 IO::Socket(3pm)