1Sys::Virt::EventImpl(3pUms)er Contributed Perl DocumentatSiyosn::Virt::EventImpl(3pm)
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NAME

6       Sys::Virt::EventImpl - Event loop implementation parent class
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DESCRIPTION

9       The "Sys::Virt::EventImpl" module represents the contract for
10       integrating libvirt with an event loop. This package is abstract and
11       intended to be subclassed to provide an actual implementation.
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13       This module is new in 9.5.0. To use this module while also supporting
14       pre-9.5.0 versions, could may consider the code below to set up
15       inheritance.
16
17         package YourImpl;
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19         use strict;
20         use warnings;
21
22         BEGIN {
23           if (require Sys::Virt::EventImpl) {
24              eval "use parent 'Sys::Virt::EventImpl';";
25           }
26           else {
27              eval "use parent 'Sys::Virt::Event';";
28           }
29         }
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EVENT LOOP IMPLEMENTATION

32       When implementing an event loop, the implementation must be a sub-class
33       of the "Sys::Virt::EventImpl" class.  It must override these functions:
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35       my $watch_id = $self->add_handle( $fd, $events, $callback, $opaque, $ff
36       )
37           Registers $callback to be invoked for $events on $fd. Use
38           "_run_handle_callback" to do the actual invocation from the event
39           loop (see "Callback helpers" below).
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41           Next to the events explicitly indicated by $events,
42           "Sys::Virt::Event::HANDLE_ERROR" and
43           "Sys::Virt::Event::HANDLE_HANGUP" should always trigger the
44           callback.
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46           Returns a positive integer $watch_id or -1 on error.
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48       $self->update_handle($watch_id, $events)
49           Replaces the events currencly triggering $watch_id with $events.
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51       my $ret = $self->remove_handle($watch_id)
52           Removes the $callback from the $fd.
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54           Returns 0 on success or -1 on failure.
55
56           IMPORTANT This should also make sure that "_free_callback_opaque"
57           is called after this function has been executed: not doing so will
58           prevent the connection from being garbage collected.
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60       my $timer_id = $self->add_timeout($frequency, $callback, $opaque, $ff)
61       $self->update_timeout($timer_id, $frequency)
62           Replaces the interval on the timer with $frequency.
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64       my $ret = $self->remove_timeout($timer_id)
65           Discards the timer.
66
67           Returns 0 on success or -1 on failure.
68
69           IMPORTANT This should also make sure that "_free_callback_opaque"
70           is called after this function has been executed: not doing so will
71           prevent the connection from being garbage collected.
72
73   Callback helpers
74       $self->_run_handle_callback($watch_id, $fd, $events, $cb, $opaque)
75           A helper method for executing a callback in response to one of more
76           $events on the file handle $fd. The $watch number is the unique
77           identifier associated with the file descriptor. The $cb and $opaque
78           parameters are the callback and data registered for the handle.
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80       $self->_run_timeout_callback($timer_id, $cb, $opaque)
81           A helper method for executing a callback in response to the expiry
82           of a timeout identified by $timer. The $cb and $opaque parameters
83           are the callback and data registered for the timeout.
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85       $self->_free_callback_opaque($ff, $opaque)
86           A helper method for freeing the data associated with a callback.
87           The $ff and $opaque parameters are the callback and data registered
88           for the handle/timeout.
89
90           IMPORTANT This helper must be called outside of any callbacks; that
91           is after the "remove_handle" or "remove_timeout" callbacks
92           complete.
93

AUTHORS

95       Daniel P. Berrange <berrange@redhat.com>
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98       Copyright (C) 2006-2009 Red Hat Copyright (C) 2006-2009 Daniel P.
99       Berrange
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LICENSE

102       This program is free software; you can redistribute it and/or modify it
103       under the terms of either the GNU General Public License as published
104       by the Free Software Foundation (either version 2 of the License, or at
105       your option any later version), or, the Artistic License, as specified
106       in the Perl README file.
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SEE ALSO

109       Sys::Virt,  "http://libvirt.org"
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113perl v5.38.0                      2023-09-08         Sys::Virt::EventImpl(3pm)
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