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Revision 1.65 by root, Sat Dec 8 14:12:03 2007 UTC vs.
Revision 1.93 by root, Tue May 20 19:52:12 2008 UTC

35 warn "sigquit received\n"; 35 warn "sigquit received\n";
36 }; 36 };
37 37
38 # CHILD/PID STATUS CHANGES 38 # CHILD/PID STATUS CHANGES
39 39
40 my $w = EV::child 666, sub { 40 my $w = EV::child 666, 0, sub {
41 my ($w, $revents) = @_; 41 my ($w, $revents) = @_;
42 my $status = $w->rstatus; 42 my $status = $w->rstatus;
43 }; 43 };
44 44
45 # STAT CHANGES 45 # STAT CHANGES
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 libev
61itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on 61itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>) for more
62watcher semantics or some discussion on the available backends, or how to 62subtle details on watcher semantics or some discussion on the available
63force a specific backend with C<LIBEV_FLAGS>, or just about in any case 63backends, or how to force a specific backend with C<LIBEV_FLAGS>, or just
64because it has much more detailed information. 64about in any case because it has much more detailed information.
65
66This module is very fast and scalable. It is actually so fast that you
67can use it through the L<AnyEvent> module, stay portable to other event
68loops (if you don't rely on any watcher types not available through it)
69and still be faster than with any other event loop currently supported in
70Perl.
65 71
66=cut 72=cut
67 73
68package EV; 74package EV;
69 75
70use strict; 76use strict;
71 77
72BEGIN { 78BEGIN {
73 our $VERSION = '1.8'; 79 our $VERSION = '3.4';
74 use XSLoader; 80 use XSLoader;
75 XSLoader::load "EV", $VERSION; 81 XSLoader::load "EV", $VERSION;
76} 82}
77 83
78@EV::IO::ISA = 84@EV::IO::ISA =
84@EV::Idle::ISA = 90@EV::Idle::ISA =
85@EV::Prepare::ISA = 91@EV::Prepare::ISA =
86@EV::Check::ISA = 92@EV::Check::ISA =
87@EV::Embed::ISA = 93@EV::Embed::ISA =
88@EV::Fork::ISA = 94@EV::Fork::ISA =
95@EV::Async::ISA =
89 "EV::Watcher"; 96 "EV::Watcher";
90 97
98@EV::Loop::Default::ISA = "EV::Loop";
99
100=head1 EVENT LOOPS
101
102EV supports multiple event loops: There is a single "default event loop"
103that can handle everything including signals and child watchers, and any
104number of "dynamic event loops" that can use different backends (with
105various limitations), but no child and signal watchers.
106
107You do not have to do anything to create the default event loop: When
108the module is loaded a suitable backend is selected on the premise of
109selecting a working backend (which for example rules out kqueue on most
110BSDs). Modules should, unless they have "special needs" always use the
111default loop as this is fastest (perl-wise), best supported by other
112modules (e.g. AnyEvent or Coro) and most portable event loop.
113
114For specific programs you can create additional event loops dynamically.
115
116=over 4
117
118=item $loop = new EV::loop [$flags]
119
120Create a new event loop as per the specified flags. Please refer to the
121C<ev_loop_new ()> function description in the libev documentation
122(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>)
123for more info.
124
125The loop will automatically be destroyed when it is no longer referenced
126by any watcher and the loop object goes out of scope.
127
128Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop
129is protected by this module.
130
131=item $loop->loop_fork
132
133Must be called after a fork in the child, before entering or continuing
134the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
135this fucntion automatically, at some performance loss (refer to the libev
136documentation).
137
138=item $loop = EV::default_loop [$flags]
139
140Return the default loop (which is a singleton object).
141
142=back
143
144
91=head1 BASIC INTERFACE 145=head1 BASIC INTERFACE
92 146
93=over 4 147=over 4
94 148
95=item $EV::DIED 149=item $EV::DIED
96 150
97Must contain a reference to a function that is called when a callback 151Must contain a reference to a function that is called when a callback
98throws an exception (with $@ containing thr error). The default prints an 152throws an exception (with $@ containing the error). The default prints an
99informative message and continues. 153informative message and continues.
100 154
101If this callback throws an exception it will be silently ignored. 155If this callback throws an exception it will be silently ignored.
102 156
157=item $flags = EV::supported_backends
158
159=item $flags = EV::recommended_backends
160
161=item $flags = EV::embeddable_backends
162
163Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
164instance of EV, the set of recommended backends (supposed to be good) for
165this platform and the set of embeddable backends (see EMBED WATCHERS).
166
167=item EV::sleep $seconds
168
169Block the process for the given number of (fractional) seconds.
170
103=item $time = EV::time 171=item $time = EV::time
104 172
105Returns the current time in (fractional) seconds since the epoch. 173Returns the current time in (fractional) seconds since the epoch.
106 174
107=item $time = EV::now 175=item $time = EV::now
176
177=item $time = $loop->now
108 178
109Returns the time the last event loop iteration has been started. This 179Returns the time the last event loop iteration has been started. This
110is the time that (relative) timers are based on, and refering to it is 180is the time that (relative) timers are based on, and refering to it is
111usually faster then calling EV::time. 181usually faster then calling EV::time.
112 182
113=item $method = EV::method 183=item $backend = EV::backend
184
185=item $backend = $loop->backend
114 186
115Returns an integer describing the backend used by libev (EV::METHOD_SELECT 187Returns an integer describing the backend used by libev (EV::METHOD_SELECT
116or EV::METHOD_EPOLL). 188or EV::METHOD_EPOLL).
117 189
118=item EV::loop [$flags] 190=item EV::loop [$flags]
191
192=item $loop->loop ([$flags])
119 193
120Begin checking for events and calling callbacks. It returns when a 194Begin checking for events and calling callbacks. It returns when a
121callback calls EV::unloop. 195callback calls EV::unloop.
122 196
123The $flags argument can be one of the following: 197The $flags argument can be one of the following:
126 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 200 EV::LOOP_ONESHOT block at most once (wait, but do not loop)
127 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 201 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
128 202
129=item EV::unloop [$how] 203=item EV::unloop [$how]
130 204
205=item $loop->unloop ([$how])
206
131When called with no arguments or an argument of EV::UNLOOP_ONE, makes the 207When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
132innermost call to EV::loop return. 208innermost call to EV::loop return.
133 209
134When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as 210When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
135fast as possible. 211fast as possible.
136 212
137=item $count = EV::loop_count 213=item $count = EV::loop_count
138 214
215=item $count = $loop->loop_count
216
139Return the number of times the event loop has polled for new 217Return the number of times the event loop has polled for new
140events. Sometiems useful as a generation counter. 218events. Sometiems useful as a generation counter.
141 219
142=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 220=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
221
222=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
143 223
144This function rolls together an I/O and a timer watcher for a single 224This function rolls together an I/O and a timer watcher for a single
145one-shot event without the need for managing a watcher object. 225one-shot event without the need for managing a watcher object.
146 226
147If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> 227If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
153If timeout is C<undef> or negative, then there will be no 233If timeout is C<undef> or negative, then there will be no
154timeout. Otherwise a EV::timer with this value will be started. 234timeout. Otherwise a EV::timer with this value will be started.
155 235
156When an error occurs or either the timeout or I/O watcher triggers, then 236When an error occurs or either the timeout or I/O watcher triggers, then
157the callback will be called with the received event set (in general 237the callback will be called with the received event set (in general
158you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>, 238you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
159C<EV::WRITE> and C<EV::TIMEOUT>). 239C<EV::WRITE> and C<EV::TIMEOUT>).
160 240
161EV::once doesn't return anything: the watchers stay active till either 241EV::once doesn't return anything: the watchers stay active till either
162of them triggers, then they will be stopped and freed, and the callback 242of them triggers, then they will be stopped and freed, and the callback
163invoked. 243invoked.
164 244
165=item EV::feed_fd_event ($fd, $revents) 245=item EV::feed_fd_event ($fd, $revents)
166 246
247=item $loop->feed_fd_event ($fd, $revents)
248
167Feed an event on a file descriptor into EV. EV will react to this call as 249Feed an event on a file descriptor into EV. EV will react to this call as
168if the readyness notifications specified by C<$revents> (a combination of 250if the readyness notifications specified by C<$revents> (a combination of
169C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. 251C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
170 252
171=item EV::feed_signal_event ($signal) 253=item EV::feed_signal_event ($signal)
172 254
173Feed a signal event into EV. EV will react to this call as if the signal 255Feed a signal event into EV. EV will react to this call as if the signal
174specified by C<$signal> had occured. 256specified by C<$signal> had occured.
175 257
176=back 258=item EV::set_io_collect_interval $time
177 259
260=item $loop->set_io_collect_interval ($time)
178 261
262=item EV::set_timeout_collect_interval $time
263
264=item $loop->set_timeout_collect_interval ($time)
265
266These advanced functions set the minimum block interval when polling for I/O events and the minimum
267wait interval for timer events. See the libev documentation at
268L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> for
269a more detailed discussion.
270
271=back
272
273
179=head2 WATCHER OBJECTS 274=head1 WATCHER OBJECTS
180 275
181A watcher is an object that gets created to record your interest in some 276A watcher is an object that gets created to record your interest in some
182event. For instance, if you want to wait for STDIN to become readable, you 277event. For instance, if you want to wait for STDIN to become readable, you
183would create an EV::io watcher for that: 278would create an EV::io watcher for that:
184 279
185 my $watcher = EV::io *STDIN, EV::READ, sub { 280 my $watcher = EV::io *STDIN, EV::READ, sub {
186 my ($watcher, $revents) = @_; 281 my ($watcher, $revents) = @_;
187 warn "yeah, STDIN should not be readable without blocking!\n" 282 warn "yeah, STDIN should now be readable without blocking!\n"
188 }; 283 };
189 284
190All watchers can be active (waiting for events) or inactive (paused). Only 285All watchers can be active (waiting for events) or inactive (paused). Only
191active watchers will have their callbacks invoked. All callbacks will be 286active watchers will have their callbacks invoked. All callbacks will be
192called with at least two arguments: the watcher and a bitmask of received 287called with at least two arguments: the watcher and a bitmask of received
276Feed some events on this watcher into EV. EV will react to this call as if 371Feed some events on this watcher into EV. EV will react to this call as if
277the watcher had received the given C<$revents> mask. 372the watcher had received the given C<$revents> mask.
278 373
279=item $revents = $w->clear_pending 374=item $revents = $w->clear_pending
280 375
281If the watcher is pending, this function returns clears its pending status 376If the watcher is pending, this function clears its pending status and
282and returns its C<$revents> bitset (as if its callback was invoked). If the 377returns its C<$revents> bitset (as if its callback was invoked). If the
283watcher isn't pending it does nothing and returns C<0>. 378watcher isn't pending it does nothing and returns C<0>.
284 379
285=item $previous_state = $w->keepalive ($bool) 380=item $previous_state = $w->keepalive ($bool)
286 381
287Normally, C<EV::loop> will return when there are no active watchers 382Normally, C<EV::loop> will return when there are no active watchers
288(which is a "deadlock" because no progress can be made anymore). This is 383(which is a "deadlock" because no progress can be made anymore). This is
289convinient because it allows you to start your watchers (and your jobs), 384convinient because it allows you to start your watchers (and your jobs),
290call C<EV::loop> once and when it returns you know that all your jobs are 385call C<EV::loop> once and when it returns you know that all your jobs are
291finished (or they forgot to register some watchers for their task :). 386finished (or they forgot to register some watchers for their task :).
292 387
293Sometimes, however, this gets in your way, for example when you the module 388Sometimes, however, this gets in your way, for example when the module
294that calls C<EV::loop> (usually the main program) is not the same module 389that calls C<EV::loop> (usually the main program) is not the same module
295as a long-living watcher (for example a DNS client module written by 390as a long-living watcher (for example a DNS client module written by
296somebody else even). Then you might want any outstanding requests to be 391somebody else even). Then you might want any outstanding requests to be
297handled, but you would not want to keep C<EV::loop> from returning just 392handled, but you would not want to keep C<EV::loop> from returning just
298because you happen to have this long-running UDP port watcher. 393because you happen to have this long-running UDP port watcher.
306Example: Register an I/O watcher for some UDP socket but do not keep the 401Example: Register an I/O watcher for some UDP socket but do not keep the
307event loop from running just because of that watcher. 402event loop from running just because of that watcher.
308 403
309 my $udp_socket = ... 404 my $udp_socket = ...
310 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 405 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
311 $udp_watcher->keepalive (0); 406 $1000udp_watcher->keepalive (0);
312 407
313=back 408=item $loop = $w->loop
314 409
410Return the loop that this watcher is attached to.
315 411
412=back
413
414
316=head2 WATCHER TYPES 415=head1 WATCHER TYPES
317 416
318Each of the following subsections describes a single watcher type. 417Each of the following subsections describes a single watcher type.
319 418
320=head3 I/O WATCHERS - is this file descriptor readable or writable? 419=head3 I/O WATCHERS - is this file descriptor readable or writable?
321 420
322=over 4 421=over 4
323 422
324=item $w = EV::io $fileno_or_fh, $eventmask, $callback 423=item $w = EV::io $fileno_or_fh, $eventmask, $callback
325 424
326=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 425=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
426
427=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
428
429=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
327 430
328As long as the returned watcher object is alive, call the C<$callback> 431As long as the returned watcher object is alive, call the C<$callback>
329when at least one of events specified in C<$eventmask> occurs. 432when at least one of events specified in C<$eventmask> occurs.
330 433
331The $eventmask can be one or more of these constants ORed together: 434The $eventmask can be one or more of these constants ORed together:
360=over 4 463=over 4
361 464
362=item $w = EV::timer $after, $repeat, $callback 465=item $w = EV::timer $after, $repeat, $callback
363 466
364=item $w = EV::timer_ns $after, $repeat, $callback 467=item $w = EV::timer_ns $after, $repeat, $callback
468
469=item $w = $loop->timer ($after, $repeat, $callback)
470
471=item $w = $loop->timer_ns ($after, $repeat, $callback)
365 472
366Calls the callback after C<$after> seconds (which may be fractional). If 473Calls the callback after C<$after> seconds (which may be fractional). If
367C<$repeat> is non-zero, the timer will be restarted (with the $repeat 474C<$repeat> is non-zero, the timer will be restarted (with the $repeat
368value as $after) after the callback returns. 475value as $after) after the callback returns.
369 476
410=over 4 517=over 4
411 518
412=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback 519=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
413 520
414=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 521=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
522
523=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
524
525=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
415 526
416Similar to EV::timer, but is not based on relative timeouts but on 527Similar to EV::timer, but is not based on relative timeouts but on
417absolute times. Apart from creating "simple" timers that trigger "at" the 528absolute times. Apart from creating "simple" timers that trigger "at" the
418specified time, it can also be used for non-drifting absolute timers and 529specified time, it can also be used for non-drifting absolute timers and
419more complex, cron-like, setups that are not adversely affected by time 530more complex, cron-like, setups that are not adversely affected by time
429This time simply fires at the wallclock time C<$at> and doesn't repeat. It 540This time simply fires at the wallclock time C<$at> and doesn't repeat. It
430will not adjust when a time jump occurs, that is, if it is to be run 541will not adjust when a time jump occurs, that is, if it is to be run
431at January 1st 2011 then it will run when the system time reaches or 542at January 1st 2011 then it will run when the system time reaches or
432surpasses this time. 543surpasses this time.
433 544
434=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 545=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
435 546
436In this mode the watcher will always be scheduled to time out at the 547In this mode the watcher will always be scheduled to time out at the
437next C<$at + N * $interval> time (for some integer N) and then repeat, 548next C<$at + N * $interval> time (for some integer N) and then repeat,
438regardless of any time jumps. 549regardless of any time jumps.
439 550
494 605
495=item $w->again 606=item $w->again
496 607
497Simply stops and starts the watcher again. 608Simply stops and starts the watcher again.
498 609
610=item $time = $w->at
611
612Return the time that the watcher is expected to trigger next.
613
499=back 614=back
500 615
501 616
502=head3 SIGNAL WATCHERS - signal me when a signal gets signalled! 617=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
503 618
536 651
537=head3 CHILD WATCHERS - watch out for process status changes 652=head3 CHILD WATCHERS - watch out for process status changes
538 653
539=over 4 654=over 4
540 655
541=item $w = EV::child $pid, $callback 656=item $w = EV::child $pid, $trace, $callback
542 657
543=item $w = EV::child_ns $pid, $callback 658=item $w = EV::child_ns $pid, $trace, $callback
544 659
660=item $w = $loop->child ($pid, $trace, $callback)
661
662=item $w = $loop->child_ns ($pid, $trace, $callback)
663
545Call the callback when a status change for pid C<$pid> (or any pid if 664Call the callback when a status change for pid C<$pid> (or any pid
546C<$pid> is 0) has been received. More precisely: when the process receives 665if C<$pid> is 0) has been received (a status change happens when the
666process terminates or is killed, or, when trace is true, additionally when
667it is stopped or continued). More precisely: when the process receives
547a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all 668a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
548changed/zombie children and call the callback. 669changed/zombie children and call the callback.
549 670
550It is valid (and fully supported) to install a child watcher after a child 671It is valid (and fully supported) to install a child watcher after a child
551has exited but before the event loop has started its next iteration (for 672has exited but before the event loop has started its next iteration (for
558You can have as many pid watchers per pid as you want, they will all be 679You can have as many pid watchers per pid as you want, they will all be
559called. 680called.
560 681
561The C<child_ns> variant doesn't start (activate) the newly created watcher. 682The C<child_ns> variant doesn't start (activate) the newly created watcher.
562 683
563=item $w->set ($pid) 684=item $w->set ($pid, $trace)
564 685
565Reconfigures the watcher, see the constructor above for details. Can be called at 686Reconfigures the watcher, see the constructor above for details. Can be called at
566any time. 687any time.
567 688
568=item $current_pid = $w->pid 689=item $current_pid = $w->pid
569 690
570=item $old_pid = $w->pid ($new_pid)
571
572Returns the previously set process id and optionally set a new one. 691Returns the previously set process id and optionally set a new one.
573 692
574=item $exit_status = $w->rstatus 693=item $exit_status = $w->rstatus
575 694
576Return the exit/wait status (as returned by waitpid, see the waitpid entry 695Return the exit/wait status (as returned by waitpid, see the waitpid entry
589=over 4 708=over 4
590 709
591=item $w = EV::stat $path, $interval, $callback 710=item $w = EV::stat $path, $interval, $callback
592 711
593=item $w = EV::stat_ns $path, $interval, $callback 712=item $w = EV::stat_ns $path, $interval, $callback
713
714=item $w = $loop->stat ($path, $interval, $callback)
715
716=item $w = $loop->stat_ns ($path, $interval, $callback)
594 717
595Call the callback when a file status change has been detected on 718Call the callback when a file status change has been detected on
596C<$path>. The C<$path> does not need to exist, changing from "path exists" 719C<$path>. The C<$path> does not need to exist, changing from "path exists"
597to "path does not exist" is a status change like any other. 720to "path does not exist" is a status change like any other.
598 721
668=over 4 791=over 4
669 792
670=item $w = EV::idle $callback 793=item $w = EV::idle $callback
671 794
672=item $w = EV::idle_ns $callback 795=item $w = EV::idle_ns $callback
796
797=item $w = $loop->idle ($callback)
798
799=item $w = $loop->idle_ns ($callback)
673 800
674Call the callback when there are no other pending watchers of the same or 801Call the callback when there are no other pending watchers of the same or
675higher priority (excluding check, prepare and other idle watchers of the 802higher priority (excluding check, prepare and other idle watchers of the
676same or lower priority, of course). They are called idle watchers because 803same or lower priority, of course). They are called idle watchers because
677when the watcher is the highest priority pending event in the process, the 804when the watcher is the highest priority pending event in the process, the
700 827
701=item $w = EV::prepare $callback 828=item $w = EV::prepare $callback
702 829
703=item $w = EV::prepare_ns $callback 830=item $w = EV::prepare_ns $callback
704 831
832=item $w = $loop->prepare ($callback)
833
834=item $w = $loop->prepare_ns ($callback)
835
705Call the callback just before the process would block. You can still 836Call the callback just before the process would block. You can still
706create/modify any watchers at this point. 837create/modify any watchers at this point.
707 838
708See the EV::check watcher, below, for explanations and an example. 839See the EV::check watcher, below, for explanations and an example.
709 840
717=over 4 848=over 4
718 849
719=item $w = EV::check $callback 850=item $w = EV::check $callback
720 851
721=item $w = EV::check_ns $callback 852=item $w = EV::check_ns $callback
853
854=item $w = $loop->check ($callback)
855
856=item $w = $loop->check_ns ($callback)
722 857
723Call the callback just after the process wakes up again (after it has 858Call the callback just after the process wakes up again (after it has
724gathered events), but before any other callbacks have been invoked. 859gathered events), but before any other callbacks have been invoked.
725 860
726This is used to integrate other event-based software into the EV 861This is used to integrate other event-based software into the EV
781 916
782=item $w = EV::fork $callback 917=item $w = EV::fork $callback
783 918
784=item $w = EV::fork_ns $callback 919=item $w = EV::fork_ns $callback
785 920
921=item $w = $loop->fork ($callback)
922
923=item $w = $loop->fork_ns ($callback)
924
786Call the callback before the event loop is resumed in the child process 925Call the callback before the event loop is resumed in the child process
787after a fork. 926after a fork.
788 927
789The C<fork_ns> variant doesn't start (activate) the newly created watcher. 928The C<fork_ns> variant doesn't start (activate) the newly created watcher.
929
930=back
931
932
933=head3 EMBED WATCHERS - when one backend isn't enough...
934
935This is a rather advanced watcher type that lets you embed one event loop
936into another (currently only IO events are supported in the embedded
937loop, other types of watchers might be handled in a delayed or incorrect
938fashion and must not be used).
939
940See the libev documentation at
941L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
942for more details.
943
944In short, this watcher is most useful on BSD systems without working
945kqueue to still be able to handle a large number of sockets:
946
947 my $socket_loop;
948
949 # check wether we use SELECT or POLL _and_ KQUEUE is supported
950 if (
951 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
952 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
953 ) {
954 # use kqueue for sockets
955 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
956 }
957
958 # use the default loop otherwise
959 $socket_loop ||= EV::default_loop;
960
961=over 4
962
963=item $w = EV::embed $otherloop, $callback
964
965=item $w = EV::embed_ns $otherloop, $callback
966
967=item $w = $loop->embed ($otherloop, $callback)
968
969=item $w = $loop->embed_ns ($otherloop, $callback)
970
971Call the callback when the embedded event loop (C<$otherloop>) has any
972I/O activity. The C<$callback> should alwas be specified as C<undef> in
973this version of EV, which means the embedded event loop will be managed
974automatically.
975
976The C<embed_ns> variant doesn't start (activate) the newly created watcher.
977
978=back
979
980=head3 ASYNC WATCHERS - how to wake up another event loop
981
982Async watchers are provided by EV, but have little use in perl directly, as perl
983neither supports threads nor direct access to signal handlers or other
984contexts where they could be of value.
985
986It is, however, possible to use them from the XS level.
987
988Please see the libev documentation for further details.
989
990=over 4
991
992=item $w = EV::async $callback
993
994=item $w = EV::async_ns $callback
995
996=item $w->send
997
998=item $bool = $w->async_pending
790 999
791=back 1000=back
792 1001
793 1002
794=head1 PERL SIGNALS 1003=head1 PERL SIGNALS
805to be called on every event loop iteration by installing a C<EV::check> 1014to be called on every event loop iteration by installing a C<EV::check>
806watcher: 1015watcher:
807 1016
808 my $async_check = EV::check sub { }; 1017 my $async_check = EV::check sub { };
809 1018
810This ensures that perl shortly gets into control for a short time, and 1019This ensures that perl gets into control for a short time to handle any
811also ensures slower overall operation. 1020pending signals, and also ensures (slightly) slower overall operation.
812 1021
813=head1 THREADS 1022=head1 THREADS
814 1023
815Threads are not supported by this module in any way. Perl pseudo-threads 1024Threads are not supported by this module in any way. Perl pseudo-threads
816is evil stuff and must die. As soon as Perl gains real threads I will work 1025is evil stuff and must die. As soon as Perl gains real threads I will work
838our $DIED = sub { 1047our $DIED = sub {
839 warn "EV: error in callback (ignoring): $@"; 1048 warn "EV: error in callback (ignoring): $@";
840}; 1049};
841 1050
842default_loop 1051default_loop
843 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; 1052 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
844 1053
8451; 10541;
846 1055
847=head1 SEE ALSO 1056=head1 SEE ALSO
848 1057
849L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as 1058L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
850event loop), L<Coro::EV> (efficient coroutines with EV). 1059event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
1060coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1061event-loop agnostic and portable event driven programming.
851 1062
852=head1 AUTHOR 1063=head1 AUTHOR
853 1064
854 Marc Lehmann <schmorp@schmorp.de> 1065 Marc Lehmann <schmorp@schmorp.de>
855 http://home.schmorp.de/ 1066 http://home.schmorp.de/

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