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Revision 1.61 by root, Thu Dec 6 03:13:07 2007 UTC vs.
Revision 1.110 by root, Wed Dec 24 22:05:58 2008 UTC

2 2
3EV - perl interface to libev, a high performance full-featured event loop 3EV - perl interface to libev, a high performance full-featured event loop
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use EV; 7 use EV;
8
9 # TIMERS
10
11 my $w = EV::timer 2, 0, sub {
12 warn "is called after 2s";
13 };
14
15 my $w = EV::timer 2, 2, sub {
16 warn "is called roughly every 2s (repeat = 2)";
17 };
18
19 undef $w; # destroy event watcher again
20
21 my $w = EV::periodic 0, 60, 0, sub {
22 warn "is called every minute, on the minute, exactly";
23 };
24
25 # IO
26
27 my $w = EV::io *STDIN, EV::READ, sub {
28 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29 warn "stdin is readable, you entered: ", <STDIN>;
30 };
31
32 # SIGNALS
33
34 my $w = EV::signal 'QUIT', sub {
35 warn "sigquit received\n";
36 };
37
38 # CHILD/PID STATUS CHANGES
8 39
9 # TIMERS 40 my $w = EV::child 666, 0, sub {
41 my ($w, $revents) = @_;
42 my $status = $w->rstatus;
43 };
10 44
11 my $w = EV::timer 2, 0, sub {
12 warn "is called after 2s";
13 };
14
15 my $w = EV::timer 2, 2, sub {
16 warn "is called roughly every 2s (repeat = 2)";
17 };
18
19 undef $w; # destroy event watcher again
20
21 my $w = EV::periodic 0, 60, 0, sub {
22 warn "is called every minute, on the minute, exactly";
23 };
24
25 # IO
26
27 my $w = EV::io *STDIN, EV::READ, sub {
28 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29 warn "stdin is readable, you entered: ", <STDIN>;
30 };
31
32 # SIGNALS
33
34 my $w = EV::signal 'QUIT', sub {
35 warn "sigquit received\n";
36 };
37
38 # CHILD/PID STATUS CHANGES
39
40 my $w = EV::child 666, sub {
41 my ($w, $revents) = @_;
42 my $status = $w->rstatus;
43 };
44
45 # STAT CHANGES 45 # STAT CHANGES
46 my $w = EV::stat "/etc/passwd", 10, sub { 46 my $w = EV::stat "/etc/passwd", 10, sub {
47 my ($w, $revents) = @_; 47 my ($w, $revents) = @_;
48 warn $w->path, " has changed somehow.\n"; 48 warn $w->path, " has changed somehow.\n";
49 }; 49 };
50 50
51 # MAINLOOP 51 # MAINLOOP
52 EV::loop; # loop until EV::unloop is called or all watchers stop 52 EV::loop; # loop until EV::unloop is called or all watchers stop
53 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled 53 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
54 EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block 54 EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
55 55
56=head1 DESCRIPTION 56=head1 DESCRIPTION
57 57
58This module provides an interface to libev 58This module provides an interface to libev
59(L<http://software.schmorp.de/pkg/libev.html>). While the documentation 59(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
60below is comprehensive, one might also consult the documentation of libev 60below is comprehensive, one might also consult the documentation of
61itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on 61libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
62watcher semantics or some discussion on the available backends, or how to 62F<perldoc EV::libev>) for more subtle details on watcher semantics or some
63force a specific backend with C<LIBEV_FLAGS>. 63discussion on the available backends, or how to force a specific backend
64with C<LIBEV_FLAGS>, or just about in any case because it has much more
65detailed information.
66
67This module is very fast and scalable. It is actually so fast that you
68can use it through the L<AnyEvent> module, stay portable to other event
69loops (if you don't rely on any watcher types not available through it)
70and still be faster than with any other event loop currently supported in
71Perl.
72
73=head2 MODULE EXPORTS
74
75This module does not export any symbols.
64 76
65=cut 77=cut
66 78
67package EV; 79package EV;
68 80
81no warnings;
69use strict; 82use strict;
70 83
71BEGIN { 84BEGIN {
72 our $VERSION = '1.6'; 85 our $VERSION = '3.51';
73 use XSLoader; 86 use XSLoader;
74 XSLoader::load "EV", $VERSION; 87 XSLoader::load "EV", $VERSION;
75} 88}
76 89
77@EV::IO::ISA = 90@EV::IO::ISA =
83@EV::Idle::ISA = 96@EV::Idle::ISA =
84@EV::Prepare::ISA = 97@EV::Prepare::ISA =
85@EV::Check::ISA = 98@EV::Check::ISA =
86@EV::Embed::ISA = 99@EV::Embed::ISA =
87@EV::Fork::ISA = 100@EV::Fork::ISA =
101@EV::Async::ISA =
88 "EV::Watcher"; 102 "EV::Watcher";
89 103
104@EV::Loop::Default::ISA = "EV::Loop";
105
106=head1 EVENT LOOPS
107
108EV supports multiple event loops: There is a single "default event loop"
109that can handle everything including signals and child watchers, and any
110number of "dynamic event loops" that can use different backends (with
111various limitations), but no child and signal watchers.
112
113You do not have to do anything to create the default event loop: When
114the module is loaded a suitable backend is selected on the premise of
115selecting a working backend (which for example rules out kqueue on most
116BSDs). Modules should, unless they have "special needs" always use the
117default loop as this is fastest (perl-wise), best supported by other
118modules (e.g. AnyEvent or Coro) and most portable event loop.
119
120For specific programs you can create additional event loops dynamically.
121
122If you want to take advantage of kqueue (which often works properly for
123sockets only) even though the default loop doesn't enable it, you can
124I<embed> a kqueue loop into the default loop: running the default loop
125will then also service the kqueue loop to some extent. See the example in
126the section about embed watchers for an example on how to achieve that.
127
128=over 4
129
130=item $loop = new EV::loop [$flags]
131
132Create a new event loop as per the specified flags. Please refer to
133the C<ev_loop_new ()> function description in the libev documentation
134(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
135or locally-installed as F<EV::libev> manpage) for more info.
136
137The loop will automatically be destroyed when it is no longer referenced
138by any watcher and the loop object goes out of scope.
139
140If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
141is recommended, as only the default event loop is protected by this
142module. If you I<are> embedding this loop in the default loop, this is not
143necessary, as C<EV::embed> automatically does the right thing on fork.
144
145=item $loop->loop_fork
146
147Must be called after a fork in the child, before entering or continuing
148the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
149this function automatically, at some performance loss (refer to the libev
150documentation).
151
152=item $loop->loop_verify
153
154Calls C<ev_verify> to make internal consistency checks (for debugging
155libev) and abort the program if any data structures were found to be
156corrupted.
157
158=item $loop = EV::default_loop [$flags]
159
160Return the default loop (which is a singleton object). Since this module
161already creates the default loop with default flags, specifying flags here
162will not have any effect unless you destroy the default loop first, which
163isn't supported. So in short: don't do it, and if you break it, you get to
164keep the pieces.
165
166=back
167
168
90=head1 BASIC INTERFACE 169=head1 BASIC INTERFACE
91 170
92=over 4 171=over 4
93 172
94=item $EV::DIED 173=item $EV::DIED
95 174
96Must contain a reference to a function that is called when a callback 175Must contain a reference to a function that is called when a callback
97throws an exception (with $@ containing thr error). The default prints an 176throws an exception (with $@ containing the error). The default prints an
98informative message and continues. 177informative message and continues.
99 178
100If this callback throws an exception it will be silently ignored. 179If this callback throws an exception it will be silently ignored.
101 180
181=item $flags = EV::supported_backends
182
183=item $flags = EV::recommended_backends
184
185=item $flags = EV::embeddable_backends
186
187Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
188instance of EV, the set of recommended backends (supposed to be good) for
189this platform and the set of embeddable backends (see EMBED WATCHERS).
190
191=item EV::sleep $seconds
192
193Block the process for the given number of (fractional) seconds.
194
102=item $time = EV::time 195=item $time = EV::time
103 196
104Returns the current time in (fractional) seconds since the epoch. 197Returns the current time in (fractional) seconds since the epoch.
105 198
106=item $time = EV::now 199=item $time = EV::now
107 200
201=item $time = $loop->now
202
108Returns the time the last event loop iteration has been started. This 203Returns the time the last event loop iteration has been started. This
109is the time that (relative) timers are based on, and refering to it is 204is the time that (relative) timers are based on, and referring to it is
110usually faster then calling EV::time. 205usually faster then calling EV::time.
111 206
112=item $method = EV::method 207=item $backend = EV::backend
113 208
209=item $backend = $loop->backend
210
114Returns an integer describing the backend used by libev (EV::METHOD_SELECT 211Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
115or EV::METHOD_EPOLL). 212or EV::BACKEND_EPOLL).
116 213
117=item EV::loop [$flags] 214=item EV::loop [$flags]
215
216=item $loop->loop ([$flags])
118 217
119Begin checking for events and calling callbacks. It returns when a 218Begin checking for events and calling callbacks. It returns when a
120callback calls EV::unloop. 219callback calls EV::unloop.
121 220
122The $flags argument can be one of the following: 221The $flags argument can be one of the following:
125 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 224 EV::LOOP_ONESHOT block at most once (wait, but do not loop)
126 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 225 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
127 226
128=item EV::unloop [$how] 227=item EV::unloop [$how]
129 228
229=item $loop->unloop ([$how])
230
130When called with no arguments or an argument of EV::UNLOOP_ONE, makes the 231When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
131innermost call to EV::loop return. 232innermost call to EV::loop return.
132 233
133When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as 234When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
134fast as possible. 235fast as possible.
135 236
136=item $count = EV::loop_count 237=item $count = EV::loop_count
137 238
239=item $count = $loop->loop_count
240
138Return the number of times the event loop has polled for new 241Return the number of times the event loop has polled for new
139events. Sometiems useful as a generation counter. 242events. Sometimes useful as a generation counter.
140 243
141=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 244=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
245
246=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
142 247
143This function rolls together an I/O and a timer watcher for a single 248This function rolls together an I/O and a timer watcher for a single
144one-shot event without the need for managing a watcher object. 249one-shot event without the need for managing a watcher object.
145 250
146If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> 251If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
152If timeout is C<undef> or negative, then there will be no 257If timeout is C<undef> or negative, then there will be no
153timeout. Otherwise a EV::timer with this value will be started. 258timeout. Otherwise a EV::timer with this value will be started.
154 259
155When an error occurs or either the timeout or I/O watcher triggers, then 260When an error occurs or either the timeout or I/O watcher triggers, then
156the callback will be called with the received event set (in general 261the callback will be called with the received event set (in general
157you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>, 262you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
158C<EV::WRITE> and C<EV::TIMEOUT>). 263C<EV::WRITE> and C<EV::TIMEOUT>).
159 264
160EV::once doesn't return anything: the watchers stay active till either 265EV::once doesn't return anything: the watchers stay active till either
161of them triggers, then they will be stopped and freed, and the callback 266of them triggers, then they will be stopped and freed, and the callback
162invoked. 267invoked.
163 268
164=back 269=item EV::feed_fd_event ($fd, $revents)
165 270
271=item $loop->feed_fd_event ($fd, $revents)
272
273Feed an event on a file descriptor into EV. EV will react to this call as
274if the readyness notifications specified by C<$revents> (a combination of
275C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
276
277=item EV::feed_signal_event ($signal)
278
279Feed a signal event into EV. EV will react to this call as if the signal
280specified by C<$signal> had occured.
281
282=item EV::set_io_collect_interval $time
283
284=item $loop->set_io_collect_interval ($time)
285
286=item EV::set_timeout_collect_interval $time
287
288=item $loop->set_timeout_collect_interval ($time)
289
290These advanced functions set the minimum block interval when polling for I/O events and the minimum
291wait interval for timer events. See the libev documentation at
292L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
293(locally installed as F<EV::libev>) for a more detailed discussion.
294
295=back
296
297
166=head2 WATCHER OBJECTS 298=head1 WATCHER OBJECTS
167 299
168A watcher is an object that gets created to record your interest in some 300A watcher is an object that gets created to record your interest in some
169event. For instance, if you want to wait for STDIN to become readable, you 301event. For instance, if you want to wait for STDIN to become readable, you
170would create an EV::io watcher for that: 302would create an EV::io watcher for that:
171 303
172 my $watcher = EV::io *STDIN, EV::READ, sub { 304 my $watcher = EV::io *STDIN, EV::READ, sub {
173 my ($watcher, $revents) = @_; 305 my ($watcher, $revents) = @_;
174 warn "yeah, STDIN should not be readable without blocking!\n" 306 warn "yeah, STDIN should now be readable without blocking!\n"
175 }; 307 };
176 308
177All watchers can be active (waiting for events) or inactive (paused). Only 309All watchers can be active (waiting for events) or inactive (paused). Only
178active watchers will have their callbacks invoked. All callbacks will be 310active watchers will have their callbacks invoked. All callbacks will be
179called with at least two arguments: the watcher and a bitmask of received 311called with at least two arguments: the watcher and a bitmask of received
180events. 312events.
181 313
182Each watcher type has its associated bit in revents, so you can use the 314Each watcher type has its associated bit in revents, so you can use the
183same callback for multiple watchers. The event mask is named after the 315same callback for multiple watchers. The event mask is named after the
184type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 316type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
185EV::periodic sets EV::PERIODIC and so on, with the exception of IO events 317EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
186(which can set both EV::READ and EV::WRITE bits), and EV::timer (which 318(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
187uses EV::TIMEOUT). 319uses EV::TIMEOUT).
188 320
189In the rare case where one wants to create a watcher but not start it at 321In the rare case where one wants to create a watcher but not start it at
190the same time, each constructor has a variant with a trailing C<_ns> in 322the same time, each constructor has a variant with a trailing C<_ns> in
212 344
213=item $w->stop 345=item $w->stop
214 346
215Stop a watcher if it is active. Also clear any pending events (events that 347Stop a watcher if it is active. Also clear any pending events (events that
216have been received but that didn't yet result in a callback invocation), 348have been received but that didn't yet result in a callback invocation),
217regardless of wether the watcher was active or not. 349regardless of whether the watcher was active or not.
218 350
219=item $bool = $w->is_active 351=item $bool = $w->is_active
220 352
221Returns true if the watcher is active, false otherwise. 353Returns true if the watcher is active, false otherwise.
222 354
252The default priority of any newly-created watcher is 0. 384The default priority of any newly-created watcher is 0.
253 385
254Note that the priority semantics have not yet been fleshed out and are 386Note that the priority semantics have not yet been fleshed out and are
255subject to almost certain change. 387subject to almost certain change.
256 388
257=item $w->trigger ($revents) 389=item $w->invoke ($revents)
258 390
259Call the callback *now* with the given event mask. 391Call the callback *now* with the given event mask.
392
393=item $w->feed_event ($revents)
394
395Feed some events on this watcher into EV. EV will react to this call as if
396the watcher had received the given C<$revents> mask.
397
398=item $revents = $w->clear_pending
399
400If the watcher is pending, this function clears its pending status and
401returns its C<$revents> bitset (as if its callback was invoked). If the
402watcher isn't pending it does nothing and returns C<0>.
260 403
261=item $previous_state = $w->keepalive ($bool) 404=item $previous_state = $w->keepalive ($bool)
262 405
263Normally, C<EV::loop> will return when there are no active watchers 406Normally, C<EV::loop> will return when there are no active watchers
264(which is a "deadlock" because no progress can be made anymore). This is 407(which is a "deadlock" because no progress can be made anymore). This is
265convinient because it allows you to start your watchers (and your jobs), 408convinient because it allows you to start your watchers (and your jobs),
266call C<EV::loop> once and when it returns you know that all your jobs are 409call C<EV::loop> once and when it returns you know that all your jobs are
267finished (or they forgot to register some watchers for their task :). 410finished (or they forgot to register some watchers for their task :).
268 411
269Sometimes, however, this gets in your way, for example when you the module 412Sometimes, however, this gets in your way, for example when the module
270that calls C<EV::loop> (usually the main program) is not the same module 413that calls C<EV::loop> (usually the main program) is not the same module
271as a long-living watcher (for example a DNS client module written by 414as a long-living watcher (for example a DNS client module written by
272somebody else even). Then you might want any outstanding requests to be 415somebody else even). Then you might want any outstanding requests to be
273handled, but you would not want to keep C<EV::loop> from returning just 416handled, but you would not want to keep C<EV::loop> from returning just
274because you happen to have this long-running UDP port watcher. 417because you happen to have this long-running UDP port watcher.
275 418
276In this case you can clear the keepalive status, which means that even 419In this case you can clear the keepalive status, which means that even
277though your watcher is active, it won't keep C<EV::loop> from returning. 420though your watcher is active, it won't keep C<EV::loop> from returning.
278 421
279The initial value for keepalive is true (enabled), and you cna change it 422The initial value for keepalive is true (enabled), and you can change it
280any time. 423any time.
281 424
282Example: Register an IO watcher for some UDP socket but do not keep the 425Example: Register an I/O watcher for some UDP socket but do not keep the
283event loop from running just because of that watcher. 426event loop from running just because of that watcher.
284 427
285 my $udp_socket = ... 428 my $udp_socket = ...
286 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 429 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
287 $udp_watcher->keepalive (0); 430 $udp_watcher->keepalive (0);
288 431
289=back 432=item $loop = $w->loop
290 433
434Return the loop that this watcher is attached to.
291 435
436=back
437
438
292=head2 WATCHER TYPES 439=head1 WATCHER TYPES
293 440
294Each of the following subsections describes a single watcher type. 441Each of the following subsections describes a single watcher type.
295 442
296=head3 IO WATCHERS - is this file descriptor readable or writable? 443=head3 I/O WATCHERS - is this file descriptor readable or writable?
297 444
298=over 4 445=over 4
299 446
300=item $w = EV::io $fileno_or_fh, $eventmask, $callback 447=item $w = EV::io $fileno_or_fh, $eventmask, $callback
301 448
302=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 449=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
450
451=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
452
453=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
303 454
304As long as the returned watcher object is alive, call the C<$callback> 455As long as the returned watcher object is alive, call the C<$callback>
305when at least one of events specified in C<$eventmask> occurs. 456when at least one of events specified in C<$eventmask> occurs.
306 457
307The $eventmask can be one or more of these constants ORed together: 458The $eventmask can be one or more of these constants ORed together:
336=over 4 487=over 4
337 488
338=item $w = EV::timer $after, $repeat, $callback 489=item $w = EV::timer $after, $repeat, $callback
339 490
340=item $w = EV::timer_ns $after, $repeat, $callback 491=item $w = EV::timer_ns $after, $repeat, $callback
492
493=item $w = $loop->timer ($after, $repeat, $callback)
494
495=item $w = $loop->timer_ns ($after, $repeat, $callback)
341 496
342Calls the callback after C<$after> seconds (which may be fractional). If 497Calls the callback after C<$after> seconds (which may be fractional). If
343C<$repeat> is non-zero, the timer will be restarted (with the $repeat 498C<$repeat> is non-zero, the timer will be restarted (with the $repeat
344value as $after) after the callback returns. 499value as $after) after the callback returns.
345 500
386=over 4 541=over 4
387 542
388=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback 543=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
389 544
390=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 545=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
546
547=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
548
549=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
391 550
392Similar to EV::timer, but is not based on relative timeouts but on 551Similar to EV::timer, but is not based on relative timeouts but on
393absolute times. Apart from creating "simple" timers that trigger "at" the 552absolute times. Apart from creating "simple" timers that trigger "at" the
394specified time, it can also be used for non-drifting absolute timers and 553specified time, it can also be used for non-drifting absolute timers and
395more complex, cron-like, setups that are not adversely affected by time 554more complex, cron-like, setups that are not adversely affected by time
405This time simply fires at the wallclock time C<$at> and doesn't repeat. It 564This time simply fires at the wallclock time C<$at> and doesn't repeat. It
406will not adjust when a time jump occurs, that is, if it is to be run 565will not adjust when a time jump occurs, that is, if it is to be run
407at January 1st 2011 then it will run when the system time reaches or 566at January 1st 2011 then it will run when the system time reaches or
408surpasses this time. 567surpasses this time.
409 568
410=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 569=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
411 570
412In this mode the watcher will always be scheduled to time out at the 571In this mode the watcher will always be scheduled to time out at the
413next C<$at + N * $interval> time (for some integer N) and then repeat, 572next C<$at + N * $interval> time (for some integer N) and then repeat,
414regardless of any time jumps. 573regardless of any time jumps.
415 574
433time the periodic watcher gets scheduled, the reschedule callback 592time the periodic watcher gets scheduled, the reschedule callback
434($reschedule_cb) will be called with the watcher as first, and the current 593($reschedule_cb) will be called with the watcher as first, and the current
435time as second argument. 594time as second argument.
436 595
437I<This callback MUST NOT stop or destroy this or any other periodic 596I<This callback MUST NOT stop or destroy this or any other periodic
438watcher, ever>. If you need to stop it, return 1e30 and stop it 597watcher, ever, and MUST NOT call any event loop functions or methods>. If
439afterwards. 598you need to stop it, return 1e30 and stop it afterwards. You may create
599and start a C<EV::prepare> watcher for this task.
440 600
441It must return the next time to trigger, based on the passed time value 601It must return the next time to trigger, based on the passed time value
442(that is, the lowest time value larger than to the second argument). It 602(that is, the lowest time value larger than or equal to to the second
443will usually be called just before the callback will be triggered, but 603argument). It will usually be called just before the callback will be
444might be called at other times, too. 604triggered, but might be called at other times, too.
445 605
446This can be used to create very complex timers, such as a timer that 606This can be used to create very complex timers, such as a timer that
447triggers on each midnight, local time (actually 24 hours after the last 607triggers on each midnight, local time (actually 24 hours after the last
448midnight, to keep the example simple. If you know a way to do it correctly 608midnight, to keep the example simple. If you know a way to do it correctly
449in about the same space (without requiring elaborate modules), drop me a 609in about the same space (without requiring elaborate modules), drop me a
470 630
471=item $w->again 631=item $w->again
472 632
473Simply stops and starts the watcher again. 633Simply stops and starts the watcher again.
474 634
635=item $time = $w->at
636
637Return the time that the watcher is expected to trigger next.
638
475=back 639=back
476 640
477 641
478=head3 SIGNAL WATCHERS - signal me when a signal gets signalled! 642=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
479 643
512 676
513=head3 CHILD WATCHERS - watch out for process status changes 677=head3 CHILD WATCHERS - watch out for process status changes
514 678
515=over 4 679=over 4
516 680
517=item $w = EV::child $pid, $callback 681=item $w = EV::child $pid, $trace, $callback
518 682
519=item $w = EV::child_ns $pid, $callback 683=item $w = EV::child_ns $pid, $trace, $callback
520 684
685=item $w = $loop->child ($pid, $trace, $callback)
686
687=item $w = $loop->child_ns ($pid, $trace, $callback)
688
521Call the callback when a status change for pid C<$pid> (or any pid if 689Call the callback when a status change for pid C<$pid> (or any pid
522C<$pid> is 0) has been received. More precisely: when the process receives 690if C<$pid> is 0) has been received (a status change happens when the
691process terminates or is killed, or, when trace is true, additionally when
692it is stopped or continued). More precisely: when the process receives
523a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all 693a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
524changed/zombie children and call the callback. 694changed/zombie children and call the callback.
525 695
526It is valid (and fully supported) to install a child watcher after a child 696It is valid (and fully supported) to install a child watcher after a child
527has exited but before the event loop has started its next iteration (for 697has exited but before the event loop has started its next iteration (for
534You can have as many pid watchers per pid as you want, they will all be 704You can have as many pid watchers per pid as you want, they will all be
535called. 705called.
536 706
537The C<child_ns> variant doesn't start (activate) the newly created watcher. 707The C<child_ns> variant doesn't start (activate) the newly created watcher.
538 708
539=item $w->set ($pid) 709=item $w->set ($pid, $trace)
540 710
541Reconfigures the watcher, see the constructor above for details. Can be called at 711Reconfigures the watcher, see the constructor above for details. Can be called at
542any time. 712any time.
543 713
544=item $current_pid = $w->pid 714=item $current_pid = $w->pid
545 715
546=item $old_pid = $w->pid ($new_pid)
547
548Returns the previously set process id and optionally set a new one. 716Returns the previously set process id and optionally set a new one.
549 717
550=item $exit_status = $w->rstatus 718=item $exit_status = $w->rstatus
551 719
552Return the exit/wait status (as returned by waitpid, see the waitpid entry 720Return the exit/wait status (as returned by waitpid, see the waitpid entry
565=over 4 733=over 4
566 734
567=item $w = EV::stat $path, $interval, $callback 735=item $w = EV::stat $path, $interval, $callback
568 736
569=item $w = EV::stat_ns $path, $interval, $callback 737=item $w = EV::stat_ns $path, $interval, $callback
738
739=item $w = $loop->stat ($path, $interval, $callback)
740
741=item $w = $loop->stat_ns ($path, $interval, $callback)
570 742
571Call the callback when a file status change has been detected on 743Call the callback when a file status change has been detected on
572C<$path>. The C<$path> does not need to exist, changing from "path exists" 744C<$path>. The C<$path> does not need to exist, changing from "path exists"
573to "path does not exist" is a status change like any other. 745to "path does not exist" is a status change like any other.
574 746
645 817
646=item $w = EV::idle $callback 818=item $w = EV::idle $callback
647 819
648=item $w = EV::idle_ns $callback 820=item $w = EV::idle_ns $callback
649 821
650Call the callback when there are no pending io, timer/periodic, signal or 822=item $w = $loop->idle ($callback)
651child events, i.e. when the process is idle. 823
824=item $w = $loop->idle_ns ($callback)
825
826Call the callback when there are no other pending watchers of the same or
827higher priority (excluding check, prepare and other idle watchers of the
828same or lower priority, of course). They are called idle watchers because
829when the watcher is the highest priority pending event in the process, the
830process is considered to be idle at that priority.
831
832If you want a watcher that is only ever called when I<no> other events are
833outstanding you have to set the priority to C<EV::MINPRI>.
652 834
653The process will not block as long as any idle watchers are active, and 835The process will not block as long as any idle watchers are active, and
654they will be called repeatedly until stopped. 836they will be called repeatedly until stopped.
655 837
838For example, if you have idle watchers at priority C<0> and C<1>, and
839an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
840and the I/O watcher will always run when ready. Only when the idle watcher
841at priority C<1> is stopped and the I/O watcher at priority C<0> is not
842pending with the C<0>-priority idle watcher be invoked.
843
656The C<idle_ns> variant doesn't start (activate) the newly created watcher. 844The C<idle_ns> variant doesn't start (activate) the newly created watcher.
657 845
658=back 846=back
659 847
660 848
663=over 4 851=over 4
664 852
665=item $w = EV::prepare $callback 853=item $w = EV::prepare $callback
666 854
667=item $w = EV::prepare_ns $callback 855=item $w = EV::prepare_ns $callback
856
857=item $w = $loop->prepare ($callback)
858
859=item $w = $loop->prepare_ns ($callback)
668 860
669Call the callback just before the process would block. You can still 861Call the callback just before the process would block. You can still
670create/modify any watchers at this point. 862create/modify any watchers at this point.
671 863
672See the EV::check watcher, below, for explanations and an example. 864See the EV::check watcher, below, for explanations and an example.
681=over 4 873=over 4
682 874
683=item $w = EV::check $callback 875=item $w = EV::check $callback
684 876
685=item $w = EV::check_ns $callback 877=item $w = EV::check_ns $callback
878
879=item $w = $loop->check ($callback)
880
881=item $w = $loop->check_ns ($callback)
686 882
687Call the callback just after the process wakes up again (after it has 883Call the callback just after the process wakes up again (after it has
688gathered events), but before any other callbacks have been invoked. 884gathered events), but before any other callbacks have been invoked.
689 885
690This is used to integrate other event-based software into the EV 886This is used to integrate other event-based software into the EV
700 or return; 896 or return;
701 897
702 # make the dispatcher handle any outstanding stuff 898 # make the dispatcher handle any outstanding stuff
703 ... not shown 899 ... not shown
704 900
705 # create an IO watcher for each and every socket 901 # create an I/O watcher for each and every socket
706 @snmp_watcher = ( 902 @snmp_watcher = (
707 (map { EV::io $_, EV::READ, sub { } } 903 (map { EV::io $_, EV::READ, sub { } }
708 keys %{ $dispatcher->{_descriptors} }), 904 keys %{ $dispatcher->{_descriptors} }),
709 905
710 EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] 906 EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
725 # make the dispatcher handle any new stuff 921 # make the dispatcher handle any new stuff
726 ... not shown 922 ... not shown
727 }; 923 };
728 924
729The callbacks of the created watchers will not be called as the watchers 925The callbacks of the created watchers will not be called as the watchers
730are destroyed before this cna happen (remember EV::check gets called 926are destroyed before this can happen (remember EV::check gets called
731first). 927first).
732 928
733The C<check_ns> variant doesn't start (activate) the newly created watcher. 929The C<check_ns> variant doesn't start (activate) the newly created watcher.
734 930
735=back 931=back
745 941
746=item $w = EV::fork $callback 942=item $w = EV::fork $callback
747 943
748=item $w = EV::fork_ns $callback 944=item $w = EV::fork_ns $callback
749 945
946=item $w = $loop->fork ($callback)
947
948=item $w = $loop->fork_ns ($callback)
949
750Call the callback before the event loop is resumed in the child process 950Call the callback before the event loop is resumed in the child process
751after a fork. 951after a fork.
752 952
753The C<fork_ns> variant doesn't start (activate) the newly created watcher. 953The C<fork_ns> variant doesn't start (activate) the newly created watcher.
954
955=back
956
957
958=head3 EMBED WATCHERS - when one backend isn't enough...
959
960This is a rather advanced watcher type that lets you embed one event loop
961into another (currently only IO events are supported in the embedded
962loop, other types of watchers might be handled in a delayed or incorrect
963fashion and must not be used).
964
965See the libev documentation at
966L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
967(locally installed as F<EV::libev>) for more details.
968
969In short, this watcher is most useful on BSD systems without working
970kqueue to still be able to handle a large number of sockets:
971
972 my $socket_loop;
973
974 # check wether we use SELECT or POLL _and_ KQUEUE is supported
975 if (
976 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
977 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
978 ) {
979 # use kqueue for sockets
980 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
981 }
982
983 # use the default loop otherwise
984 $socket_loop ||= EV::default_loop;
985
986=over 4
987
988=item $w = EV::embed $otherloop[, $callback]
989
990=item $w = EV::embed_ns $otherloop[, $callback]
991
992=item $w = $loop->embed ($otherloop[, $callback])
993
994=item $w = $loop->embed_ns ($otherloop[, $callback])
995
996Call the callback when the embedded event loop (C<$otherloop>) has any
997I/O activity. The C<$callback> is optional: if it is missing, then the
998embedded event loop will be managed automatically (which is recommended),
999otherwise you have to invoke C<sweep> yourself.
1000
1001The C<embed_ns> variant doesn't start (activate) the newly created watcher.
1002
1003=back
1004
1005=head3 ASYNC WATCHERS - how to wake up another event loop
1006
1007Async watchers are provided by EV, but have little use in perl directly, as perl
1008neither supports threads nor direct access to signal handlers or other
1009contexts where they could be of value.
1010
1011It is, however, possible to use them from the XS level.
1012
1013Please see the libev documentation for further details.
1014
1015=over 4
1016
1017=item $w = EV::async $callback
1018
1019=item $w = EV::async_ns $callback
1020
1021=item $w->send
1022
1023=item $bool = $w->async_pending
754 1024
755=back 1025=back
756 1026
757 1027
758=head1 PERL SIGNALS 1028=head1 PERL SIGNALS
769to be called on every event loop iteration by installing a C<EV::check> 1039to be called on every event loop iteration by installing a C<EV::check>
770watcher: 1040watcher:
771 1041
772 my $async_check = EV::check sub { }; 1042 my $async_check = EV::check sub { };
773 1043
774This ensures that perl shortly gets into control for a short time, and 1044This ensures that perl gets into control for a short time to handle any
775also ensures slower overall operation. 1045pending signals, and also ensures (slightly) slower overall operation.
776 1046
777=head1 THREADS 1047=head1 THREADS
778 1048
779Threads are not supported by this module in any way. Perl pseudo-threads 1049Threads are not supported by this module in any way. Perl pseudo-threads
780is evil stuff and must die. As soon as Perl gains real threads I will work 1050is evil stuff and must die. As soon as Perl gains real threads I will work
802our $DIED = sub { 1072our $DIED = sub {
803 warn "EV: error in callback (ignoring): $@"; 1073 warn "EV: error in callback (ignoring): $@";
804}; 1074};
805 1075
806default_loop 1076default_loop
807 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; 1077 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
808 1078
8091; 10791;
810 1080
811=head1 SEE ALSO 1081=head1 SEE ALSO
812 1082
813L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as 1083L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
814event loop), L<Coro::EV> (efficient coroutines with EV). 1084event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
1085coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1086event-loop agnostic and portable event driven programming.
815 1087
816=head1 AUTHOR 1088=head1 AUTHOR
817 1089
818 Marc Lehmann <schmorp@schmorp.de> 1090 Marc Lehmann <schmorp@schmorp.de>
819 http://home.schmorp.de/ 1091 http://home.schmorp.de/
820 1092
821=cut 1093=cut
822 1094

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