1Glib::MainLoop(3) User Contributed Perl Documentation Glib::MainLoop(3)
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6 Glib::MainLoop - An event source manager
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9 Event-driven programs need some sort of loop which watches for events
10 and launches the appropriate actions. Glib::MainLoop provides this
11 functionality.
12 Mainloops have context, provided by the MainContext object. For the
14 most part you can use the default context (see "default"), but if you
15 want to create a subcontext for a nested loop which doesn't have the
16 same event sources, etc, you can.
17 Event sources, attached to main contexts, watch for events to happen,
19 and launch appropriate actions. Glib provides a few ready-made event
20 sources, the Glib::Timeout, Glib::Idle, and io watch
21 ("Glib::IO->add_watch").
22 Under the hood, Gtk+ adds event sources for GdkEvents to dispatch
24 events to your widgets. In fact, Gtk2 provides an abstraction of
25 Glib::MainLoop (See "Gtk2->main" and friends), so you may rarely have
26 cause to use Glib::MainLoop directly.
27 Note: As of version 1.080, the Glib module uses a custom event source
29 to ensure that perl's safe signal handling and the glib polling event
30 loop play nicely together. It is no longer necessary to install a
31 timeout to ensure that async signals get handled in a timely manner.
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34 "SOURCE_REMOVE" and "SOURCE_CONTINUE" are designed for use as the
35 return values from timeout, idle and I/O watch source functions. They
36 return true to keep running or false to remove themselves. These
37 constants can help you get that the right way around.
38 Glib::SOURCE_CONTINUE # true
40 Glib::SOURCE_REMOVE # false
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43 maincontext thingamabob = Glib::MainContext->new
44 mainloop = Glib::MainLoop->new ($context=undef, $is_running=FALSE)
45 · $context (Glib::MainContext thingamabob)
46 · $is_running (boolean)
48 integer = Glib::Timeout->add ($interval, $callback, $data=undef,
50 $priority=G_PRIORITY_DEFAULT)
51 · $interval (integer) number of milliseconds
52 · $callback (subroutine)
54 · $data (scalar)
56 · $priority (integer)
58 Run $callback every $interval milliseconds until $callback returns
60 false. Returns a source id which may be used with
61 "Glib::Source->remove". Note that a mainloop must be active for the
62 timeout to execute.
63 integer = Glib::Idle->add ($callback, $data=undef,
65 $priority=G_PRIORITY_DEFAULT_IDLE)
66 · $callback (subroutine)
67 · $data (scalar)
69 · $priority (integer)
71 Run $callback when the mainloop is idle. If $callback returns false,
73 it will uninstall itself, otherwise, it will run again at the next idle
74 iteration. Returns a source id which may be used with
75 "Glib::Source->remove".
76 integer = Glib::Timeout->add_seconds ($interval, $callback, $data=undef,
78 $priority=G_PRIORITY_DEFAULT)
79 · $interval (integer)
80 · $callback (scalar)
82 · $data (scalar)
84 · $priority (integer)
86 Since: glib 2.14
88 integer = Glib::IO->add_watch ($fd, $condition, $callback, $data=undef,
90 $priority=G_PRIORITY_DEFAULT)
91 · $fd (integer) file descriptor, e.g. fileno($filehandle)
92 · $condition (Glib::IOCondition)
94 · $callback (subroutine)
96 · $data (scalar)
98 · $priority (integer)
100 Run $callback when there is an event on $fd that matches $condition.
102 The watch uninstalls itself if $callback returns false. Returns a
103 source id that may be used with "Glib::Source->remove".
104 Glib's IO channels serve the same basic purpose as Perl's file handles,
106 so for the most part you don't see GIOChannels in Perl. The IO watch
107 integrates IO operations with the main loop, which Perl file handles
108 don't do. For various reasons, this function requires raw file
109 descriptors, not full file handles. See "fileno" in perlfunc.
110 maincontext thingamabob = $loop->get_context
112 maincontext thingamabob = Glib::MainContext->default
113 boolean = $context->is_owner
114 Since: glib 2.12
115 boolean = $loop->is_running
117 boolean = $context->iteration ($may_block)
118 · $may_block (boolean)
119 integer = Glib::main_depth
121 Find the current main loop recursion level. This is handy in fringe
122 situations, but those are very rare; see the C API reference for a more
123 in-depth discussion.
124 Since: glib 2.4
126 boolean = $context->pending
128 $loop->quit
129 boolean = Glib::Source->remove ($tag)
130 · $tag (integer)
131 Remove an event source. $tag is the number returned by things like
133 "Glib::Timeout->add", "Glib::Idle->add", and "Glib::IO->add_watch".
134 $loop->run
136 integer = Glib::Child->watch_add ($pid, $callback, $data=undef,
137 $priority=G_PRIORITY_DEFAULT)
138 · $pid (integer) child process ID
139 · $callback (subroutine)
141 · $data (scalar)
143 · $priority (integer)
145 Add a source to the default main context which will call
147 &$callback ($pid, $waitstatus, $data)
149 when child process $pid terminates. The return value is a source id
151 which can be used with "Glib::Source->remove". When the callback is
152 made the source is removed automatically.
153 In a non-threaded program Glib implements this source by installing a
155 SIGCHLD handler. Don't change $SIG{CHLD} in Perl or the callback will
156 never run.
157 Since: glib 2.4
159
161 flags Glib::IOCondition
162 · 'in' / 'G_IO_IN'
163 · 'out' / 'G_IO_OUT'
165 · 'pri' / 'G_IO_PRI'
167 · 'err' / 'G_IO_ERR'
169 · 'hup' / 'G_IO_HUP'
171 · 'nval' / 'G_IO_NVAL'
173
175 Glib
176
178 Copyright (C) 2003-2011 by the gtk2-perl team.
179 This software is licensed under the LGPL. See Glib for a full notice.
181perl v5.30.0 2019-07-29 Glib::MainLoop(3)