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Revision 1.61 by root, Thu Dec 6 03:13:07 2007 UTC vs.
Revision 1.90 by root, Sat Apr 26 03:34:24 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
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://cvs.schmorp.de/libev/ev.html>) for more subtle details on
62watcher semantics or some discussion on the available backends, or how to 62watcher semantics or some discussion on the available backends, or how to
63force a specific backend with C<LIBEV_FLAGS>. 63force a specific backend with C<LIBEV_FLAGS>, or just about in any case
64because 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.
64 71
65=cut 72=cut
66 73
67package EV; 74package EV;
68 75
69use strict; 76use strict;
70 77
71BEGIN { 78BEGIN {
72 our $VERSION = '1.6'; 79 our $VERSION = '3.31';
73 use XSLoader; 80 use XSLoader;
74 XSLoader::load "EV", $VERSION; 81 XSLoader::load "EV", $VERSION;
75} 82}
76 83
77@EV::IO::ISA = 84@EV::IO::ISA =
83@EV::Idle::ISA = 90@EV::Idle::ISA =
84@EV::Prepare::ISA = 91@EV::Prepare::ISA =
85@EV::Check::ISA = 92@EV::Check::ISA =
86@EV::Embed::ISA = 93@EV::Embed::ISA =
87@EV::Fork::ISA = 94@EV::Fork::ISA =
95@EV::Async::ISA =
88 "EV::Watcher"; 96 "EV::Watcher";
89 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
90=head1 BASIC INTERFACE 145=head1 BASIC INTERFACE
91 146
92=over 4 147=over 4
93 148
94=item $EV::DIED 149=item $EV::DIED
95 150
96Must 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
97throws an exception (with $@ containing thr error). The default prints an 152throws an exception (with $@ containing the error). The default prints an
98informative message and continues. 153informative message and continues.
99 154
100If this callback throws an exception it will be silently ignored. 155If this callback throws an exception it will be silently ignored.
101 156
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
102=item $time = EV::time 171=item $time = EV::time
103 172
104Returns the current time in (fractional) seconds since the epoch. 173Returns the current time in (fractional) seconds since the epoch.
105 174
106=item $time = EV::now 175=item $time = EV::now
176
177=item $time = $loop->now
107 178
108Returns the time the last event loop iteration has been started. This 179Returns 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 180is the time that (relative) timers are based on, and refering to it is
110usually faster then calling EV::time. 181usually faster then calling EV::time.
111 182
112=item $method = EV::method 183=item $backend = EV::backend
184
185=item $backend = $loop->backend
113 186
114Returns an integer describing the backend used by libev (EV::METHOD_SELECT 187Returns an integer describing the backend used by libev (EV::METHOD_SELECT
115or EV::METHOD_EPOLL). 188or EV::METHOD_EPOLL).
116 189
117=item EV::loop [$flags] 190=item EV::loop [$flags]
191
192=item $loop->loop ([$flags])
118 193
119Begin checking for events and calling callbacks. It returns when a 194Begin checking for events and calling callbacks. It returns when a
120callback calls EV::unloop. 195callback calls EV::unloop.
121 196
122The $flags argument can be one of the following: 197The $flags argument can be one of the following:
125 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 200 EV::LOOP_ONESHOT block at most once (wait, but do not loop)
126 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 201 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
127 202
128=item EV::unloop [$how] 203=item EV::unloop [$how]
129 204
205=item $loop->unloop ([$how])
206
130When 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
131innermost call to EV::loop return. 208innermost call to EV::loop return.
132 209
133When 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
134fast as possible. 211fast as possible.
135 212
136=item $count = EV::loop_count 213=item $count = EV::loop_count
137 214
215=item $count = $loop->loop_count
216
138Return the number of times the event loop has polled for new 217Return the number of times the event loop has polled for new
139events. Sometiems useful as a generation counter. 218events. Sometiems useful as a generation counter.
140 219
141=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))
142 223
143This 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
144one-shot event without the need for managing a watcher object. 225one-shot event without the need for managing a watcher object.
145 226
146If 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>
152If timeout is C<undef> or negative, then there will be no 233If timeout is C<undef> or negative, then there will be no
153timeout. Otherwise a EV::timer with this value will be started. 234timeout. Otherwise a EV::timer with this value will be started.
154 235
155When 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
156the callback will be called with the received event set (in general 237the 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>, 238you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
158C<EV::WRITE> and C<EV::TIMEOUT>). 239C<EV::WRITE> and C<EV::TIMEOUT>).
159 240
160EV::once doesn't return anything: the watchers stay active till either 241EV::once doesn't return anything: the watchers stay active till either
161of 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
162invoked. 243invoked.
163 244
164=back 245=item EV::feed_fd_event ($fd, $revents)
165 246
247=item $loop->feed_fd_event ($fd, $revents)
248
249Feed an event on a file descriptor into EV. EV will react to this call as
250if the readyness notifications specified by C<$revents> (a combination of
251C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
252
253=item EV::feed_signal_event ($signal)
254
255Feed a signal event into EV. EV will react to this call as if the signal
256specified by C<$signal> had occured.
257
258=item EV::set_io_collect_interval $time
259
260=item $loop->set_io_collect_interval ($time)
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
166=head2 WATCHER OBJECTS 274=head1 WATCHER OBJECTS
167 275
168A 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
169event. 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
170would create an EV::io watcher for that: 278would create an EV::io watcher for that:
171 279
172 my $watcher = EV::io *STDIN, EV::READ, sub { 280 my $watcher = EV::io *STDIN, EV::READ, sub {
173 my ($watcher, $revents) = @_; 281 my ($watcher, $revents) = @_;
174 warn "yeah, STDIN should not be readable without blocking!\n" 282 warn "yeah, STDIN should now be readable without blocking!\n"
175 }; 283 };
176 284
177All watchers can be active (waiting for events) or inactive (paused). Only 285All watchers can be active (waiting for events) or inactive (paused). Only
178active watchers will have their callbacks invoked. All callbacks will be 286active watchers will have their callbacks invoked. All callbacks will be
179called 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
180events. 288events.
181 289
182Each watcher type has its associated bit in revents, so you can use the 290Each 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 291same callback for multiple watchers. The event mask is named after the
184type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 292type, 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 293EV::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 294(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
187uses EV::TIMEOUT). 295uses EV::TIMEOUT).
188 296
189In the rare case where one wants to create a watcher but not start it at 297In 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 298the same time, each constructor has a variant with a trailing C<_ns> in
212 320
213=item $w->stop 321=item $w->stop
214 322
215Stop a watcher if it is active. Also clear any pending events (events that 323Stop 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), 324have been received but that didn't yet result in a callback invocation),
217regardless of wether the watcher was active or not. 325regardless of whether the watcher was active or not.
218 326
219=item $bool = $w->is_active 327=item $bool = $w->is_active
220 328
221Returns true if the watcher is active, false otherwise. 329Returns true if the watcher is active, false otherwise.
222 330
252The default priority of any newly-created watcher is 0. 360The default priority of any newly-created watcher is 0.
253 361
254Note that the priority semantics have not yet been fleshed out and are 362Note that the priority semantics have not yet been fleshed out and are
255subject to almost certain change. 363subject to almost certain change.
256 364
257=item $w->trigger ($revents) 365=item $w->invoke ($revents)
258 366
259Call the callback *now* with the given event mask. 367Call the callback *now* with the given event mask.
368
369=item $w->feed_event ($revents)
370
371Feed some events on this watcher into EV. EV will react to this call as if
372the watcher had received the given C<$revents> mask.
373
374=item $revents = $w->clear_pending
375
376If the watcher is pending, this function clears its pending status and
377returns its C<$revents> bitset (as if its callback was invoked). If the
378watcher isn't pending it does nothing and returns C<0>.
260 379
261=item $previous_state = $w->keepalive ($bool) 380=item $previous_state = $w->keepalive ($bool)
262 381
263Normally, C<EV::loop> will return when there are no active watchers 382Normally, 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 383(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), 384convinient 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 385call 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 :). 386finished (or they forgot to register some watchers for their task :).
268 387
269Sometimes, however, this gets in your way, for example when you the module 388Sometimes, 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 389that 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 390as a long-living watcher (for example a DNS client module written by
272somebody else even). Then you might want any outstanding requests to be 391somebody 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 392handled, but you would not want to keep C<EV::loop> from returning just
274because you happen to have this long-running UDP port watcher. 393because you happen to have this long-running UDP port watcher.
277though your watcher is active, it won't keep C<EV::loop> from returning. 396though your watcher is active, it won't keep C<EV::loop> from returning.
278 397
279The initial value for keepalive is true (enabled), and you cna change it 398The initial value for keepalive is true (enabled), and you cna change it
280any time. 399any time.
281 400
282Example: Register an IO 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
283event loop from running just because of that watcher. 402event loop from running just because of that watcher.
284 403
285 my $udp_socket = ... 404 my $udp_socket = ...
286 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 405 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
287 $udp_watcher->keepalive (0); 406 $1000udp_watcher->keepalive (0);
288 407
289=back 408=item $loop = $w->loop
290 409
410Return the loop that this watcher is attached to.
291 411
412=back
413
414
292=head2 WATCHER TYPES 415=head1 WATCHER TYPES
293 416
294Each of the following subsections describes a single watcher type. 417Each of the following subsections describes a single watcher type.
295 418
296=head3 IO WATCHERS - is this file descriptor readable or writable? 419=head3 I/O WATCHERS - is this file descriptor readable or writable?
297 420
298=over 4 421=over 4
299 422
300=item $w = EV::io $fileno_or_fh, $eventmask, $callback 423=item $w = EV::io $fileno_or_fh, $eventmask, $callback
301 424
302=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, $callback)
303 430
304As long as the returned watcher object is alive, call the C<$callback> 431As long as the returned watcher object is alive, call the C<$callback>
305when at least one of events specified in C<$eventmask> occurs. 432when at least one of events specified in C<$eventmask> occurs.
306 433
307The $eventmask can be one or more of these constants ORed together: 434The $eventmask can be one or more of these constants ORed together:
336=over 4 463=over 4
337 464
338=item $w = EV::timer $after, $repeat, $callback 465=item $w = EV::timer $after, $repeat, $callback
339 466
340=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, $callback)
341 472
342Calls the callback after C<$after> seconds (which may be fractional). If 473Calls the callback after C<$after> seconds (which may be fractional). If
343C<$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
344value as $after) after the callback returns. 475value as $after) after the callback returns.
345 476
386=over 4 517=over 4
387 518
388=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback 519=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
389 520
390=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, $callback)
391 526
392Similar to EV::timer, but is not based on relative timeouts but on 527Similar to EV::timer, but is not based on relative timeouts but on
393absolute times. Apart from creating "simple" timers that trigger "at" the 528absolute times. Apart from creating "simple" timers that trigger "at" the
394specified time, it can also be used for non-drifting absolute timers and 529specified time, it can also be used for non-drifting absolute timers and
395more complex, cron-like, setups that are not adversely affected by time 530more complex, cron-like, setups that are not adversely affected by time
405This time simply fires at the wallclock time C<$at> and doesn't repeat. It 540This time simply fires at the wallclock time C<$at> and doesn't repeat. It
406will not adjust when a time jump occurs, that is, if it is to be run 541will not adjust when a time jump occurs, that is, if it is to be run
407at January 1st 2011 then it will run when the system time reaches or 542at January 1st 2011 then it will run when the system time reaches or
408surpasses this time. 543surpasses this time.
409 544
410=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 545=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
411 546
412In this mode the watcher will always be scheduled to time out at the 547In this mode the watcher will always be scheduled to time out at the
413next C<$at + N * $interval> time (for some integer N) and then repeat, 548next C<$at + N * $interval> time (for some integer N) and then repeat,
414regardless of any time jumps. 549regardless of any time jumps.
415 550
470 605
471=item $w->again 606=item $w->again
472 607
473Simply stops and starts the watcher again. 608Simply stops and starts the watcher again.
474 609
610=item $time = $w->at
611
612Return the time that the watcher is expected to trigger next.
613
475=back 614=back
476 615
477 616
478=head3 SIGNAL WATCHERS - signal me when a signal gets signalled! 617=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
479 618
512 651
513=head3 CHILD WATCHERS - watch out for process status changes 652=head3 CHILD WATCHERS - watch out for process status changes
514 653
515=over 4 654=over 4
516 655
517=item $w = EV::child $pid, $callback 656=item $w = EV::child $pid, $trace, $callback
518 657
519=item $w = EV::child_ns $pid, $callback 658=item $w = EV::child_ns $pid, $trace, $callback
520 659
660=item $w = $loop->child ($pid, $trace, $callback)
661
662=item $w = $loop->child_ns ($pid, $trace, $callback)
663
521Call the callback when a status change for pid C<$pid> (or any pid if 664Call the callback when a status change for pid C<$pid> (or any pid
522C<$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
523a 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
524changed/zombie children and call the callback. 669changed/zombie children and call the callback.
525 670
526It 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
527has 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
534You 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
535called. 680called.
536 681
537The 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.
538 683
539=item $w->set ($pid) 684=item $w->set ($pid, $trace)
540 685
541Reconfigures 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
542any time. 687any time.
543 688
544=item $current_pid = $w->pid 689=item $current_pid = $w->pid
545 690
546=item $old_pid = $w->pid ($new_pid)
547
548Returns the previously set process id and optionally set a new one. 691Returns the previously set process id and optionally set a new one.
549 692
550=item $exit_status = $w->rstatus 693=item $exit_status = $w->rstatus
551 694
552Return 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
565=over 4 708=over 4
566 709
567=item $w = EV::stat $path, $interval, $callback 710=item $w = EV::stat $path, $interval, $callback
568 711
569=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, $callback)
570 717
571Call the callback when a file status change has been detected on 718Call the callback when a file status change has been detected on
572C<$path>. The C<$path> does not need to exist, changing from "path exists" 719C<$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. 720to "path does not exist" is a status change like any other.
574 721
645 792
646=item $w = EV::idle $callback 793=item $w = EV::idle $callback
647 794
648=item $w = EV::idle_ns $callback 795=item $w = EV::idle_ns $callback
649 796
650Call the callback when there are no pending io, timer/periodic, signal or 797=item $w = $loop->idle ($callback)
651child events, i.e. when the process is idle. 798
799=item $w = $loop->idle_ns ($callback)
800
801Call the callback when there are no other pending watchers of the same or
802higher priority (excluding check, prepare and other idle watchers of the
803same or lower priority, of course). They are called idle watchers because
804when the watcher is the highest priority pending event in the process, the
805process is considered to be idle at that priority.
806
807If you want a watcher that is only ever called when I<no> other events are
808outstanding you have to set the priority to C<EV::MINPRI>.
652 809
653The process will not block as long as any idle watchers are active, and 810The process will not block as long as any idle watchers are active, and
654they will be called repeatedly until stopped. 811they will be called repeatedly until stopped.
655 812
813For example, if you have idle watchers at priority C<0> and C<1>, and
814an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
815and the I/O watcher will always run when ready. Only when the idle watcher
816at priority C<1> is stopped and the I/O watcher at priority C<0> is not
817pending with the C<0>-priority idle watcher be invoked.
818
656The C<idle_ns> variant doesn't start (activate) the newly created watcher. 819The C<idle_ns> variant doesn't start (activate) the newly created watcher.
657 820
658=back 821=back
659 822
660 823
663=over 4 826=over 4
664 827
665=item $w = EV::prepare $callback 828=item $w = EV::prepare $callback
666 829
667=item $w = EV::prepare_ns $callback 830=item $w = EV::prepare_ns $callback
831
832=item $w = $loop->prepare ($callback)
833
834=item $w = $loop->prepare_ns ($callback)
668 835
669Call the callback just before the process would block. You can still 836Call the callback just before the process would block. You can still
670create/modify any watchers at this point. 837create/modify any watchers at this point.
671 838
672See the EV::check watcher, below, for explanations and an example. 839See the EV::check watcher, below, for explanations and an example.
681=over 4 848=over 4
682 849
683=item $w = EV::check $callback 850=item $w = EV::check $callback
684 851
685=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)
686 857
687Call 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
688gathered events), but before any other callbacks have been invoked. 859gathered events), but before any other callbacks have been invoked.
689 860
690This is used to integrate other event-based software into the EV 861This is used to integrate other event-based software into the EV
700 or return; 871 or return;
701 872
702 # make the dispatcher handle any outstanding stuff 873 # make the dispatcher handle any outstanding stuff
703 ... not shown 874 ... not shown
704 875
705 # create an IO watcher for each and every socket 876 # create an I/O watcher for each and every socket
706 @snmp_watcher = ( 877 @snmp_watcher = (
707 (map { EV::io $_, EV::READ, sub { } } 878 (map { EV::io $_, EV::READ, sub { } }
708 keys %{ $dispatcher->{_descriptors} }), 879 keys %{ $dispatcher->{_descriptors} }),
709 880
710 EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] 881 EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
745 916
746=item $w = EV::fork $callback 917=item $w = EV::fork $callback
747 918
748=item $w = EV::fork_ns $callback 919=item $w = EV::fork_ns $callback
749 920
921=item $w = $loop->fork ($callback)
922
923=item $w = $loop->fork_ns ($callback)
924
750Call 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
751after a fork. 926after a fork.
752 927
753The 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
754 999
755=back 1000=back
756 1001
757 1002
758=head1 PERL SIGNALS 1003=head1 PERL SIGNALS
769to 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>
770watcher: 1015watcher:
771 1016
772 my $async_check = EV::check sub { }; 1017 my $async_check = EV::check sub { };
773 1018
774This 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
775also ensures slower overall operation. 1020pending signals, and also ensures (slightly) slower overall operation.
776 1021
777=head1 THREADS 1022=head1 THREADS
778 1023
779Threads 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
780is 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
802our $DIED = sub { 1047our $DIED = sub {
803 warn "EV: error in callback (ignoring): $@"; 1048 warn "EV: error in callback (ignoring): $@";
804}; 1049};
805 1050
806default_loop 1051default_loop
807 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; 1052 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
808 1053
8091; 10541;
810 1055
811=head1 SEE ALSO 1056=head1 SEE ALSO
812 1057
813L<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
814event 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.
815 1062
816=head1 AUTHOR 1063=head1 AUTHOR
817 1064
818 Marc Lehmann <schmorp@schmorp.de> 1065 Marc Lehmann <schmorp@schmorp.de>
819 http://home.schmorp.de/ 1066 http://home.schmorp.de/

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