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Revision 1.69 by root, Tue Dec 11 21:04:40 2007 UTC vs.
Revision 1.99 by root, Tue Jul 8 09:37:37 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 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 = '3.42';
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";
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
116If you want to take avdantage of kqueue (which often works properly for
117sockets only) even though the default loop doesn't enable it, you can
118I<embed> a kqueue loop into the default loop: running the default loop
119will then also service the kqueue loop to some extent. See the example in
120the section about embed watchers for an example on how to achieve that.
121
122=over 4
123
124=item $loop = new EV::loop [$flags]
125
126Create a new event loop as per the specified flags. Please refer to the
127C<ev_loop_new ()> function description in the libev documentation
128(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>)
129for more info.
130
131The loop will automatically be destroyed when it is no longer referenced
132by any watcher and the loop object goes out of scope.
133
134Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop
135is protected by this module.
136
137=item $loop->loop_fork
138
139Must be called after a fork in the child, before entering or continuing
140the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
141this function automatically, at some performance loss (refer to the libev
142documentation).
143
144=item $loop->loop_verify
145
146Calls C<ev_verify> to make internal consistency checks (for debugging
147libev) and abort the program if any data structures were found to be
148corrupted.
149
150=item $loop = EV::default_loop [$flags]
151
152Return the default loop (which is a singleton object). Since this module
153already creates the default loop with default flags, specifying flags here
154will not have any effect unless you destroy the default loop first, which
155isn't supported. So in short: don't do it, and if you break it, you get to
156keep the pieces.
157
158=back
159
90 160
91=head1 BASIC INTERFACE 161=head1 BASIC INTERFACE
92 162
93=over 4 163=over 4
94 164
… …
98throws an exception (with $@ containing the error). The default prints an 168throws an exception (with $@ containing the error). The default prints an
99informative message and continues. 169informative message and continues.
100 170
101If this callback throws an exception it will be silently ignored. 171If this callback throws an exception it will be silently ignored.
102 172
173=item $flags = EV::supported_backends
174
175=item $flags = EV::recommended_backends
176
177=item $flags = EV::embeddable_backends
178
179Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
180instance of EV, the set of recommended backends (supposed to be good) for
181this platform and the set of embeddable backends (see EMBED WATCHERS).
182
183=item EV::sleep $seconds
184
185Block the process for the given number of (fractional) seconds.
186
103=item $time = EV::time 187=item $time = EV::time
104 188
105Returns the current time in (fractional) seconds since the epoch. 189Returns the current time in (fractional) seconds since the epoch.
106 190
107=item $time = EV::now 191=item $time = EV::now
192
193=item $time = $loop->now
108 194
109Returns the time the last event loop iteration has been started. This 195Returns 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 196is the time that (relative) timers are based on, and refering to it is
111usually faster then calling EV::time. 197usually faster then calling EV::time.
112 198
113=item $method = EV::method 199=item $backend = EV::backend
200
201=item $backend = $loop->backend
114 202
115Returns an integer describing the backend used by libev (EV::METHOD_SELECT 203Returns an integer describing the backend used by libev (EV::METHOD_SELECT
116or EV::METHOD_EPOLL). 204or EV::METHOD_EPOLL).
117 205
118=item EV::loop [$flags] 206=item EV::loop [$flags]
207
208=item $loop->loop ([$flags])
119 209
120Begin checking for events and calling callbacks. It returns when a 210Begin checking for events and calling callbacks. It returns when a
121callback calls EV::unloop. 211callback calls EV::unloop.
122 212
123The $flags argument can be one of the following: 213The $flags argument can be one of the following:
… …
126 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 216 EV::LOOP_ONESHOT block at most once (wait, but do not loop)
127 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 217 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
128 218
129=item EV::unloop [$how] 219=item EV::unloop [$how]
130 220
221=item $loop->unloop ([$how])
222
131When called with no arguments or an argument of EV::UNLOOP_ONE, makes the 223When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
132innermost call to EV::loop return. 224innermost call to EV::loop return.
133 225
134When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as 226When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
135fast as possible. 227fast as possible.
136 228
137=item $count = EV::loop_count 229=item $count = EV::loop_count
138 230
231=item $count = $loop->loop_count
232
139Return the number of times the event loop has polled for new 233Return the number of times the event loop has polled for new
140events. Sometiems useful as a generation counter. 234events. Sometiems useful as a generation counter.
141 235
142=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 236=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
237
238=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
143 239
144This function rolls together an I/O and a timer watcher for a single 240This function rolls together an I/O and a timer watcher for a single
145one-shot event without the need for managing a watcher object. 241one-shot event without the need for managing a watcher object.
146 242
147If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> 243If 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 249If timeout is C<undef> or negative, then there will be no
154timeout. Otherwise a EV::timer with this value will be started. 250timeout. Otherwise a EV::timer with this value will be started.
155 251
156When an error occurs or either the timeout or I/O watcher triggers, then 252When 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 253the 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>, 254you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
159C<EV::WRITE> and C<EV::TIMEOUT>). 255C<EV::WRITE> and C<EV::TIMEOUT>).
160 256
161EV::once doesn't return anything: the watchers stay active till either 257EV::once doesn't return anything: the watchers stay active till either
162of them triggers, then they will be stopped and freed, and the callback 258of them triggers, then they will be stopped and freed, and the callback
163invoked. 259invoked.
164 260
165=item EV::feed_fd_event ($fd, $revents) 261=item EV::feed_fd_event ($fd, $revents)
166 262
263=item $loop->feed_fd_event ($fd, $revents)
264
167Feed an event on a file descriptor into EV. EV will react to this call as 265Feed an event on a file descriptor into EV. EV will react to this call as
168if the readyness notifications specified by C<$revents> (a combination of 266if the readyness notifications specified by C<$revents> (a combination of
169C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. 267C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
170 268
171=item EV::feed_signal_event ($signal) 269=item EV::feed_signal_event ($signal)
172 270
173Feed a signal event into EV. EV will react to this call as if the signal 271Feed a signal event into EV. EV will react to this call as if the signal
174specified by C<$signal> had occured. 272specified by C<$signal> had occured.
175 273
176=back 274=item EV::set_io_collect_interval $time
177 275
276=item $loop->set_io_collect_interval ($time)
178 277
278=item EV::set_timeout_collect_interval $time
279
280=item $loop->set_timeout_collect_interval ($time)
281
282These advanced functions set the minimum block interval when polling for I/O events and the minimum
283wait interval for timer events. See the libev documentation at
284L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> for
285a more detailed discussion.
286
287=back
288
289
179=head2 WATCHER OBJECTS 290=head1 WATCHER OBJECTS
180 291
181A watcher is an object that gets created to record your interest in some 292A 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 293event. For instance, if you want to wait for STDIN to become readable, you
183would create an EV::io watcher for that: 294would create an EV::io watcher for that:
184 295
185 my $watcher = EV::io *STDIN, EV::READ, sub { 296 my $watcher = EV::io *STDIN, EV::READ, sub {
186 my ($watcher, $revents) = @_; 297 my ($watcher, $revents) = @_;
187 warn "yeah, STDIN should not be readable without blocking!\n" 298 warn "yeah, STDIN should now be readable without blocking!\n"
188 }; 299 };
189 300
190All watchers can be active (waiting for events) or inactive (paused). Only 301All watchers can be active (waiting for events) or inactive (paused). Only
191active watchers will have their callbacks invoked. All callbacks will be 302active watchers will have their callbacks invoked. All callbacks will be
192called with at least two arguments: the watcher and a bitmask of received 303called with at least two arguments: the watcher and a bitmask of received
193events. 304events.
… …
276Feed some events on this watcher into EV. EV will react to this call as if 387Feed some events on this watcher into EV. EV will react to this call as if
277the watcher had received the given C<$revents> mask. 388the watcher had received the given C<$revents> mask.
278 389
279=item $revents = $w->clear_pending 390=item $revents = $w->clear_pending
280 391
281If the watcher is pending, this function returns clears its pending status 392If the watcher is pending, this function clears its pending status and
282and returns its C<$revents> bitset (as if its callback was invoked). If the 393returns its C<$revents> bitset (as if its callback was invoked). If the
283watcher isn't pending it does nothing and returns C<0>. 394watcher isn't pending it does nothing and returns C<0>.
284 395
285=item $previous_state = $w->keepalive ($bool) 396=item $previous_state = $w->keepalive ($bool)
286 397
287Normally, C<EV::loop> will return when there are no active watchers 398Normally, 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 399(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), 400convinient 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 401call 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 :). 402finished (or they forgot to register some watchers for their task :).
292 403
293Sometimes, however, this gets in your way, for example when you the module 404Sometimes, 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 405that 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 406as a long-living watcher (for example a DNS client module written by
296somebody else even). Then you might want any outstanding requests to be 407somebody 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 408handled, but you would not want to keep C<EV::loop> from returning just
298because you happen to have this long-running UDP port watcher. 409because you happen to have this long-running UDP port watcher.
… …
308 419
309 my $udp_socket = ... 420 my $udp_socket = ...
310 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 421 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
311 $udp_watcher->keepalive (0); 422 $udp_watcher->keepalive (0);
312 423
313=back 424=item $loop = $w->loop
314 425
426Return the loop that this watcher is attached to.
315 427
428=back
429
430
316=head2 WATCHER TYPES 431=head1 WATCHER TYPES
317 432
318Each of the following subsections describes a single watcher type. 433Each of the following subsections describes a single watcher type.
319 434
320=head3 I/O WATCHERS - is this file descriptor readable or writable? 435=head3 I/O WATCHERS - is this file descriptor readable or writable?
321 436
322=over 4 437=over 4
323 438
324=item $w = EV::io $fileno_or_fh, $eventmask, $callback 439=item $w = EV::io $fileno_or_fh, $eventmask, $callback
325 440
326=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 441=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
442
443=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
444
445=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
327 446
328As long as the returned watcher object is alive, call the C<$callback> 447As long as the returned watcher object is alive, call the C<$callback>
329when at least one of events specified in C<$eventmask> occurs. 448when at least one of events specified in C<$eventmask> occurs.
330 449
331The $eventmask can be one or more of these constants ORed together: 450The $eventmask can be one or more of these constants ORed together:
… …
360=over 4 479=over 4
361 480
362=item $w = EV::timer $after, $repeat, $callback 481=item $w = EV::timer $after, $repeat, $callback
363 482
364=item $w = EV::timer_ns $after, $repeat, $callback 483=item $w = EV::timer_ns $after, $repeat, $callback
484
485=item $w = $loop->timer ($after, $repeat, $callback)
486
487=item $w = $loop->timer_ns ($after, $repeat, $callback)
365 488
366Calls the callback after C<$after> seconds (which may be fractional). If 489Calls the callback after C<$after> seconds (which may be fractional). If
367C<$repeat> is non-zero, the timer will be restarted (with the $repeat 490C<$repeat> is non-zero, the timer will be restarted (with the $repeat
368value as $after) after the callback returns. 491value as $after) after the callback returns.
369 492
… …
410=over 4 533=over 4
411 534
412=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback 535=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
413 536
414=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 537=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
538
539=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
540
541=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
415 542
416Similar to EV::timer, but is not based on relative timeouts but on 543Similar to EV::timer, but is not based on relative timeouts but on
417absolute times. Apart from creating "simple" timers that trigger "at" the 544absolute times. Apart from creating "simple" timers that trigger "at" the
418specified time, it can also be used for non-drifting absolute timers and 545specified time, it can also be used for non-drifting absolute timers and
419more complex, cron-like, setups that are not adversely affected by time 546more complex, cron-like, setups that are not adversely affected by time
… …
429This time simply fires at the wallclock time C<$at> and doesn't repeat. It 556This time simply fires at the wallclock time C<$at> and doesn't repeat. It
430will not adjust when a time jump occurs, that is, if it is to be run 557will not adjust when a time jump occurs, that is, if it is to be run
431at January 1st 2011 then it will run when the system time reaches or 558at January 1st 2011 then it will run when the system time reaches or
432surpasses this time. 559surpasses this time.
433 560
434=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 561=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
435 562
436In this mode the watcher will always be scheduled to time out at the 563In this mode the watcher will always be scheduled to time out at the
437next C<$at + N * $interval> time (for some integer N) and then repeat, 564next C<$at + N * $interval> time (for some integer N) and then repeat,
438regardless of any time jumps. 565regardless of any time jumps.
439 566
… …
457time the periodic watcher gets scheduled, the reschedule callback 584time the periodic watcher gets scheduled, the reschedule callback
458($reschedule_cb) will be called with the watcher as first, and the current 585($reschedule_cb) will be called with the watcher as first, and the current
459time as second argument. 586time as second argument.
460 587
461I<This callback MUST NOT stop or destroy this or any other periodic 588I<This callback MUST NOT stop or destroy this or any other periodic
462watcher, ever>. If you need to stop it, return 1e30 and stop it 589watcher, ever, and MUST NOT call any event loop functions or methods>. If
463afterwards. 590you need to stop it, return 1e30 and stop it afterwards. You may create
591and start a C<EV::prepare> watcher for this task.
464 592
465It must return the next time to trigger, based on the passed time value 593It must return the next time to trigger, based on the passed time value
466(that is, the lowest time value larger than to the second argument). It 594(that is, the lowest time value larger than or equal to to the second
467will usually be called just before the callback will be triggered, but 595argument). It will usually be called just before the callback will be
468might be called at other times, too. 596triggered, but might be called at other times, too.
469 597
470This can be used to create very complex timers, such as a timer that 598This can be used to create very complex timers, such as a timer that
471triggers on each midnight, local time (actually 24 hours after the last 599triggers on each midnight, local time (actually 24 hours after the last
472midnight, to keep the example simple. If you know a way to do it correctly 600midnight, to keep the example simple. If you know a way to do it correctly
473in about the same space (without requiring elaborate modules), drop me a 601in about the same space (without requiring elaborate modules), drop me a
… …
494 622
495=item $w->again 623=item $w->again
496 624
497Simply stops and starts the watcher again. 625Simply stops and starts the watcher again.
498 626
627=item $time = $w->at
628
629Return the time that the watcher is expected to trigger next.
630
499=back 631=back
500 632
501 633
502=head3 SIGNAL WATCHERS - signal me when a signal gets signalled! 634=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
503 635
… …
536 668
537=head3 CHILD WATCHERS - watch out for process status changes 669=head3 CHILD WATCHERS - watch out for process status changes
538 670
539=over 4 671=over 4
540 672
541=item $w = EV::child $pid, $callback 673=item $w = EV::child $pid, $trace, $callback
542 674
543=item $w = EV::child_ns $pid, $callback 675=item $w = EV::child_ns $pid, $trace, $callback
544 676
677=item $w = $loop->child ($pid, $trace, $callback)
678
679=item $w = $loop->child_ns ($pid, $trace, $callback)
680
545Call the callback when a status change for pid C<$pid> (or any pid if 681Call 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 682if C<$pid> is 0) has been received (a status change happens when the
683process terminates or is killed, or, when trace is true, additionally when
684it is stopped or continued). More precisely: when the process receives
547a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all 685a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
548changed/zombie children and call the callback. 686changed/zombie children and call the callback.
549 687
550It is valid (and fully supported) to install a child watcher after a child 688It 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 689has 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 696You can have as many pid watchers per pid as you want, they will all be
559called. 697called.
560 698
561The C<child_ns> variant doesn't start (activate) the newly created watcher. 699The C<child_ns> variant doesn't start (activate) the newly created watcher.
562 700
563=item $w->set ($pid) 701=item $w->set ($pid, $trace)
564 702
565Reconfigures the watcher, see the constructor above for details. Can be called at 703Reconfigures the watcher, see the constructor above for details. Can be called at
566any time. 704any time.
567 705
568=item $current_pid = $w->pid 706=item $current_pid = $w->pid
569 707
570=item $old_pid = $w->pid ($new_pid)
571
572Returns the previously set process id and optionally set a new one. 708Returns the previously set process id and optionally set a new one.
573 709
574=item $exit_status = $w->rstatus 710=item $exit_status = $w->rstatus
575 711
576Return the exit/wait status (as returned by waitpid, see the waitpid entry 712Return the exit/wait status (as returned by waitpid, see the waitpid entry
… …
589=over 4 725=over 4
590 726
591=item $w = EV::stat $path, $interval, $callback 727=item $w = EV::stat $path, $interval, $callback
592 728
593=item $w = EV::stat_ns $path, $interval, $callback 729=item $w = EV::stat_ns $path, $interval, $callback
730
731=item $w = $loop->stat ($path, $interval, $callback)
732
733=item $w = $loop->stat_ns ($path, $interval, $callback)
594 734
595Call the callback when a file status change has been detected on 735Call the callback when a file status change has been detected on
596C<$path>. The C<$path> does not need to exist, changing from "path exists" 736C<$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. 737to "path does not exist" is a status change like any other.
598 738
… …
668=over 4 808=over 4
669 809
670=item $w = EV::idle $callback 810=item $w = EV::idle $callback
671 811
672=item $w = EV::idle_ns $callback 812=item $w = EV::idle_ns $callback
813
814=item $w = $loop->idle ($callback)
815
816=item $w = $loop->idle_ns ($callback)
673 817
674Call the callback when there are no other pending watchers of the same or 818Call the callback when there are no other pending watchers of the same or
675higher priority (excluding check, prepare and other idle watchers of the 819higher priority (excluding check, prepare and other idle watchers of the
676same or lower priority, of course). They are called idle watchers because 820same or lower priority, of course). They are called idle watchers because
677when the watcher is the highest priority pending event in the process, the 821when the watcher is the highest priority pending event in the process, the
… …
700 844
701=item $w = EV::prepare $callback 845=item $w = EV::prepare $callback
702 846
703=item $w = EV::prepare_ns $callback 847=item $w = EV::prepare_ns $callback
704 848
849=item $w = $loop->prepare ($callback)
850
851=item $w = $loop->prepare_ns ($callback)
852
705Call the callback just before the process would block. You can still 853Call the callback just before the process would block. You can still
706create/modify any watchers at this point. 854create/modify any watchers at this point.
707 855
708See the EV::check watcher, below, for explanations and an example. 856See the EV::check watcher, below, for explanations and an example.
709 857
… …
717=over 4 865=over 4
718 866
719=item $w = EV::check $callback 867=item $w = EV::check $callback
720 868
721=item $w = EV::check_ns $callback 869=item $w = EV::check_ns $callback
870
871=item $w = $loop->check ($callback)
872
873=item $w = $loop->check_ns ($callback)
722 874
723Call the callback just after the process wakes up again (after it has 875Call the callback just after the process wakes up again (after it has
724gathered events), but before any other callbacks have been invoked. 876gathered events), but before any other callbacks have been invoked.
725 877
726This is used to integrate other event-based software into the EV 878This is used to integrate other event-based software into the EV
… …
781 933
782=item $w = EV::fork $callback 934=item $w = EV::fork $callback
783 935
784=item $w = EV::fork_ns $callback 936=item $w = EV::fork_ns $callback
785 937
938=item $w = $loop->fork ($callback)
939
940=item $w = $loop->fork_ns ($callback)
941
786Call the callback before the event loop is resumed in the child process 942Call the callback before the event loop is resumed in the child process
787after a fork. 943after a fork.
788 944
789The C<fork_ns> variant doesn't start (activate) the newly created watcher. 945The C<fork_ns> variant doesn't start (activate) the newly created watcher.
946
947=back
948
949
950=head3 EMBED WATCHERS - when one backend isn't enough...
951
952This is a rather advanced watcher type that lets you embed one event loop
953into another (currently only IO events are supported in the embedded
954loop, other types of watchers might be handled in a delayed or incorrect
955fashion and must not be used).
956
957See the libev documentation at
958L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
959for more details.
960
961In short, this watcher is most useful on BSD systems without working
962kqueue to still be able to handle a large number of sockets:
963
964 my $socket_loop;
965
966 # check wether we use SELECT or POLL _and_ KQUEUE is supported
967 if (
968 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
969 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
970 ) {
971 # use kqueue for sockets
972 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
973 }
974
975 # use the default loop otherwise
976 $socket_loop ||= EV::default_loop;
977
978=over 4
979
980=item $w = EV::embed $otherloop, $callback
981
982=item $w = EV::embed_ns $otherloop, $callback
983
984=item $w = $loop->embed ($otherloop, $callback)
985
986=item $w = $loop->embed_ns ($otherloop, $callback)
987
988Call the callback when the embedded event loop (C<$otherloop>) has any
989I/O activity. The C<$callback> should alwas be specified as C<undef> in
990this version of EV, which means the embedded event loop will be managed
991automatically.
992
993The C<embed_ns> variant doesn't start (activate) the newly created watcher.
994
995=back
996
997=head3 ASYNC WATCHERS - how to wake up another event loop
998
999Async watchers are provided by EV, but have little use in perl directly, as perl
1000neither supports threads nor direct access to signal handlers or other
1001contexts where they could be of value.
1002
1003It is, however, possible to use them from the XS level.
1004
1005Please see the libev documentation for further details.
1006
1007=over 4
1008
1009=item $w = EV::async $callback
1010
1011=item $w = EV::async_ns $callback
1012
1013=item $w->send
1014
1015=item $bool = $w->async_pending
790 1016
791=back 1017=back
792 1018
793 1019
794=head1 PERL SIGNALS 1020=head1 PERL SIGNALS
… …
805to be called on every event loop iteration by installing a C<EV::check> 1031to be called on every event loop iteration by installing a C<EV::check>
806watcher: 1032watcher:
807 1033
808 my $async_check = EV::check sub { }; 1034 my $async_check = EV::check sub { };
809 1035
810This ensures that perl shortly gets into control for a short time, and 1036This ensures that perl gets into control for a short time to handle any
811also ensures slower overall operation. 1037pending signals, and also ensures (slightly) slower overall operation.
812 1038
813=head1 THREADS 1039=head1 THREADS
814 1040
815Threads are not supported by this module in any way. Perl pseudo-threads 1041Threads 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 1042is evil stuff and must die. As soon as Perl gains real threads I will work
… …
844 1070
8451; 10711;
846 1072
847=head1 SEE ALSO 1073=head1 SEE ALSO
848 1074
849L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as 1075L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
850event loop), L<Coro::EV> (efficient coroutines with EV). 1076event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
1077coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1078event-loop agnostic and portable event driven programming.
851 1079
852=head1 AUTHOR 1080=head1 AUTHOR
853 1081
854 Marc Lehmann <schmorp@schmorp.de> 1082 Marc Lehmann <schmorp@schmorp.de>
855 http://home.schmorp.de/ 1083 http://home.schmorp.de/
856 1084
857=cut 1085=cut
858 1086

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