NAME

Net::TCP - TCP sockets interface module

SYNOPSIS

use Socket;			# optional
use Net::Gen;		# optional
use Net::Inet;		# optional
use Net::TCP;

DESCRIPTION

The Net::TCP module provides services for TCP communications over sockets. It is layered atop the Net::Inet and Net::Gen modules, which are part of the same distribution.

Public Methods

The following methods are provided by the Net::TCP module itself, rather than just being inherited from Net::Inet or Net::Gen.

new

Usage:

$obj = new Net::TCP;
$obj = new Net::TCP $host, $service;
$obj = new Net::TCP \%parameters;
$obj = new Net::TCP $host, $service, \%parameters;

Returns a newly-initialised object of the given class. If called for a derived class, no validation of the supplied parameters will be performed. (This is so that the derived class can add the parameter validation it needs to the object before allowing the validation.) Otherwise, it will cause the parameters to be validated by calling its init method, which Net::TCP inherits from Net::Inet. In particular, this means that if both a host and a service are given, that an object will only be returned if a connect() call was successful.

Server::new

Usage:

$obj = new Net::TCP::Server $service;
$obj = new Net::TCP::Server $service, \%parameters;
$obj = new Net::TCP::Server $lcladdr, $service, \%parameters;

Returns a newly-initialised object of the given class. This is much like the regular new method, except that it makes it easier to specify just a service name or port number, and it automatically does a setsockopt() call to set SO_REUSEADDR to make the bind() more likely to succeed.

Simple example for server setup:

    $lh = new Net::TCP::Server 7788 or die;
    while ($sh = $lh->accept) {
	defined($pid=fork) or die "fork: $!\n";
	if ($pid) {		# parent doesn't need client fh
	    $sh->stopio;
	    next;
	}
	# child doesn't need listener fh
	$lh->stopio;
	# do per-connection stuff here
	exit;
    }

Note that signal-handling for the child processes is not included in this example. A sample server will be included in the final kit which will show how to manage the subprocesses.

accept

Usage:

$newobj = $obj->accept;

Returns a new object in the same class as the given object if an accept() call succeeds, and undef otherwise.

Protected Methods

none.

Known Socket Options

These are the socket options known to the Net::TCP module itself:

TCP_NODELAY, TCP_MAXSEG, TCP_RPTR2RXT

Known Object Parameters

There are no object parameters registered by the Net::TCP module itself.

TIESCALAR

Tieing of scalars to a TCP handle is supported by inheritance from the TIESCALAR method of Net::Gen. That method only succeeds if a call to a new method results in an object for which the isconnected method returns true, which is why it is mentioned in connection with this module.

Example:

tie $x,Net::TCP,0,'finger' or die;
$x = "-s\n";
print $y while defined($y = $x);
untie $x;

This is an expensive re-implementation of finger -s on many machines.

Each assignment to the tied scalar is really a call to the put method (via the STORE method), and each read from the tied scalar is really a call to the getline method (via the FETCH method).

Exports

default

none

exportable

TCPOPT_EOL, TCPOPT_MAXSEG, TCPOPT_NOP, TCPOPT_WINDOW, TCP_MAXSEG, TCP_MAXWIN, TCP_MAX_WINSHIFT, TCP_MSS, TCP_NODELAY, TCP_RPTR2RXT, TH_ACK, TH_FIN, TH_PUSH, TH_RST, TH_SYN, TH_URG

tags

:sockopts

This tag gets you the known socket options, TCP_MAXSEG, TCP_NODELAY, and TCP_RPTR2RXT.

AUTHOR

Spider Boardman <spider@Orb.Nashua.NH.US>