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Net::UDP(3pm) User Contributed Perl Documentation Net::UDP(3pm)
NAME
Net::UDP - UDP sockets interface module
SYNOPSIS
use Net::Gen; # optional
use Net::Inet; # optional
use Net::UDP;
DESCRIPTION
The "Net::UDP" module provides services for UDP 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::UDP" module itself, rather than just being
inherited from "Net::Inet" or "Net::Gen".
new Usage:
$obj = new Net::UDP;
$obj = new Net::UDP $desthost, $destservice;
$obj = new Net::UDP \%parameters;
$obj = new Net::UDP $desthost, $destservice, \%parameters;
$obj = 'Net::UDP'->new();
$obj = 'Net::UDP'->new($desthost);
$obj = 'Net::UDP'->new($desthost, $destservice);
$obj = 'Net::UDP'->new(\%parameters);
$obj = 'Net::UDP'->new($desthost, $destservice, \%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::UDP" 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.
The examples above show the indirect object syntax which many prefer, as well as the
guaranteed-to-be-safe static method call. There are occasional problems with the
indirect object syntax, which tend to be rather obscure when encountered. See
http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-01/msg01674.html for
details.
PRINT
Usage:
$ok = $obj->PRINT(@args);
$ok = print $tied_fh @args;
This method, intended to be used with tied filehandles, behaves like one of two
inherited methods from the "Net::Gen" class, depending on the setting of the object
parameter "unbuffered_output". If that parameter is false (the default), then the
normal print() builtin is used. If the "unbuffered_output" parameter is true, then
each print() operation will actually result in a call to the "send" method, requiring
that the object be connected or that its message is in response to its last normal
recv() (with a "flags" parameter of 0). The value of the $\ variable is ignored in
that case, but the $, variable is still used if the @args array has multiple elements.
READLINE
Usage:
$line_or_datagram = $obj->READLINE;
$line_or_datagram = <TIED_FH>;
$line_or_datagram = readline(TIED_FH);
@lines_or_datagrams = $obj->READLINE;
@lines_or_datagrams = <TIED_FH>;
@lines_or_datagrams = readline(TIED_FH);
This method, intended to be used with tied filehandles, behaves like one of two
inherited methods from the "Net::Gen" class, depending on the setting of the object
parameter "unbuffered_input". If that parameter is false (the default), then this
method does line-buffering of its input as defined by the current setting of the $/
variable. If the <unbuffered_input> parameter is true, then the input records will be
exact recv() datagrams, disregarding the setting of the $/ variable. Note that
invoking the "READLINE" method in list context is likely to hang, since UDP sockets
typically don't return EOF.
Protected Methods
none.
Known Socket Options
There are no object parameters registered by the "Net::UDP" module itself.
Known Object Parameters
The following object parameters are registered by the "Net::UDP" module (as distinct from
being inherited from "Net::Gen" or "Net::Inet"):
unbuffered_input
If true, the "READLINE" operation on tied filehandles will return each recv() buffer
as though it were a single separate line, independently of the setting of the $/
variable. The default is false, which causes the "READLINE" interface to return lines
split at boundaries as appropriate for $/. (The "READLINE" method for tied
filehandles is the "<FH>" operation.) Note that calling the "READLINE" method in list
context is likely to hang for UDP sockets.
unbuffered_output
If true, the "PRINT" operation on tied filehandles will result in calls to the send()
builtin rather than the print() builtin, as described in "PRINT" above. The default
is false, which causes the "PRINT" method to use the print() builtin.
unbuffered_IO
This object parameter's value is unreliable on "getparam" or "getparams" method calls.
It is provided as a handy way to set both the "unbuffered_output" and
"unbuffered_input" object parameters to the same value at the same time during "new"
calls.
TIESCALAR support
Tieing of scalars to a UDP 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 regard to
this module.
Example:
tie $x,'Net::UDP',0,'daytime' or die "tie to Net::UDP: $!";
$x = "\n"; $x = "\n";
print $y if defined($y = $x);
untie $x;
This is an expensive re-implementation of "date" 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 "READLINE" method (via
the "FETCH" method).
TIEHANDLE support
As inherited from "Net::Inet" and "Net::Gen", with the addition of unbuffered I/O options
for the "READLINE" and "PRINT" methods.
Example:
tie *FH,'Net::UDP',{unbuffered_IO => 1, thisport => $n, thishost => 0}
or die;
while (<FH>) {
last if is_shutdown_msg($_);
print FH response($_);
}
untie *FH;
This shows how to make a UDP-based filehandle return (and send) datagrams even when used
in the usual perlish paradigm. For some applications, this can be helpful to avoid
cluttering the message processing code with the details of handling datagrams. In
particular, this example relies on the underlying support for replying to the last address
in a recvfrom() for datagram sockets, thus hiding the details of tracking and using that
information.
Exports
none
THREADING STATUS
This module has been tested with threaded perls, and should be as thread-safe as perl
itself. (As of 5.005_03 and 5.005_57, that's not all that safe just yet.) It also works
with interpreter-based threads ('ithreads') in more recent perl releases.
SEE ALSO
Net::Inet(3), Net::Gen(3)
AUTHOR
Spider Boardman <spidb AT cpan.org>
perl v5.10.0 2009-03-05 Net::UDP(3pm)
Generated by $Id: phpMan.php,v 4.49 2006/02/26 13:18:18 chedong Exp $ Author: Che Dong
On Apache
Under GNU General Public License
2012-05-24 21:52 @38.107.179.240 Crawled by CCBot/1.0 (+http://www.commoncrawl.org/bot.html)