1Sys::Virt::EventImpl(3pUms)er Contributed Perl DocumentatSiyosn::Virt::EventImpl(3pm)
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6 Sys::Virt::EventImpl - Event loop implementation parent class
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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.
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17 package YourImpl;
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19 use strict;
20 use warnings;
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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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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.
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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.
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67 Returns 0 on success or -1 on failure.
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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.
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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.
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90 IMPORTANT This helper must be called outside of any callbacks; that
91 is after the "remove_handle" or "remove_timeout" callbacks
92 complete.
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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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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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109 Sys::Virt, "http://libvirt.org"
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113perl v5.38.0 2023-09-08 Sys::Virt::EventImpl(3pm)