<html><head><meta name="color-scheme" content="light dark"></head><body><pre style="word-wrap: break-word; white-space: pre-wrap;">#!/usr/bin/perl

package X11::Protocol::Connection;

# Copyright (C) 1997 Stephen McCamant. All rights reserved. This program
# is free software; you can redistribute and/or modify it under the same
# terms as Perl itself.

use Carp;
use strict;
use vars '$VERSION';

$VERSION = 0.01;

sub give {
    croak "X11 connection object doesn't support output";
}

sub get {
    croak "X11 connection object doesn't support input";
}

sub fh {
    croak "X11 connection object is incompatible with perl filehandles";
}

sub open {
    croak "X11 connection object can't open itself";
}

1;
__END__

=head1 NAME

X11::Protocol::Connection - Perl module abstract base class for X11 client to server connections

=head1 SYNOPSIS

  # In connection object module
  package X11::Protocol::Connection::CarrierPigeon;
  use X11::Protocol::Connection;
  @ISA = ('X11::Protocol::Connection');
  sub open { ... }
  sub give { ... }
  sub get { ... }
  sub fh { ... }
  ...

  # In program
  $connection = X11::Protocol::Connection::CarrierPigeon
    -&gt;open($host, $display_number);
  $x = X11::Protocol-&gt;new($connection);

  $connection-&gt;give($data);

  $reply = unpack("I", $connection-&gt;get(4));

  use IO::Select;
  $sel = IO::select-&gt;new($connection-&gt;fh);
  if ($sel-&gt;can_read == $connection-&gt;fh) ...

=head1 DESCRIPTION

This module is an abstract base class for the various
X11::Protocol::Connection::* modules that provide connections to X
servers for the X11::Protocol module. It provides stubs for the
following methods:

=head2 open

  $conn = X11::Protocol::Connection::Foo-&gt;open($host, $display_num)

Open a connection to the specified display (numbered from 0) on the
specified $host.

=head2 give

  $conn-&gt;give($data)

Send the given data to the server. Normally, this method is used only
by the protocol module itself.

=head2 get

  $data = $conn-&gt;get($n)

Read $n bytes of data from the server. Normally, this method is used
only by the protocol module itself.

=head2 fh

  $filehandle = $conn-&gt;fh

Return an object suitable for use as a filehandle. This is mainly
useful for doing select() and other such system calls.

=head1 AUTHOR

Stephen McCamant &lt;SMCCAM@cpan.org&gt;.

=head1 SEE ALSO

L&lt;perl(1)&gt;,
L&lt;X11::Protocol&gt;,
L&lt;X11::Protocol::Connection::Socket&gt;,
L&lt;X11::Protocol::Connection::FileHandle&gt;,
L&lt;X11::Protocol::Connection::INETSocket&gt;,
L&lt;X11::Protocol::Connection::UNIXSocket&gt;,
L&lt;X11::Protocol::Connection::INETFH&gt;,
L&lt;X11::Protocol::Connection::UNIXFH&gt;.

=cut
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