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Revision 1.72 by root, Thu Dec 20 07:12:57 2007 UTC vs.
Revision 1.121 by root, Sun Jul 19 03:12:28 2009 UTC

2 2
3EV - perl interface to libev, a high performance full-featured event loop 3EV - perl interface to libev, a high performance full-featured event loop
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use EV; 7 use EV;
8
9 # TIMERS
10
11 my $w = EV::timer 2, 0, sub {
12 warn "is called after 2s";
13 };
14
15 my $w = EV::timer 2, 2, sub {
16 warn "is called roughly every 2s (repeat = 2)";
17 };
18
19 undef $w; # destroy event watcher again
20
21 my $w = EV::periodic 0, 60, 0, sub {
22 warn "is called every minute, on the minute, exactly";
23 };
24
25 # IO
26
27 my $w = EV::io *STDIN, EV::READ, sub {
28 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29 warn "stdin is readable, you entered: ", <STDIN>;
30 };
31
32 # SIGNALS
33
34 my $w = EV::signal 'QUIT', sub {
35 warn "sigquit received\n";
36 };
37
38 # CHILD/PID STATUS CHANGES
8 39
9 # TIMERS 40 my $w = EV::child 666, 0, sub {
41 my ($w, $revents) = @_;
42 my $status = $w->rstatus;
43 };
10 44
11 my $w = EV::timer 2, 0, sub {
12 warn "is called after 2s";
13 };
14
15 my $w = EV::timer 2, 2, sub {
16 warn "is called roughly every 2s (repeat = 2)";
17 };
18
19 undef $w; # destroy event watcher again
20
21 my $w = EV::periodic 0, 60, 0, sub {
22 warn "is called every minute, on the minute, exactly";
23 };
24
25 # IO
26
27 my $w = EV::io *STDIN, EV::READ, sub {
28 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29 warn "stdin is readable, you entered: ", <STDIN>;
30 };
31
32 # SIGNALS
33
34 my $w = EV::signal 'QUIT', sub {
35 warn "sigquit received\n";
36 };
37
38 # CHILD/PID STATUS CHANGES
39
40 my $w = EV::child 666, sub {
41 my ($w, $revents) = @_;
42 my $status = $w->rstatus;
43 };
44
45 # STAT CHANGES 45 # STAT CHANGES
46 my $w = EV::stat "/etc/passwd", 10, sub { 46 my $w = EV::stat "/etc/passwd", 10, sub {
47 my ($w, $revents) = @_; 47 my ($w, $revents) = @_;
48 warn $w->path, " has changed somehow.\n"; 48 warn $w->path, " has changed somehow.\n";
49 }; 49 };
50 50
51 # MAINLOOP 51 # MAINLOOP
52 EV::loop; # loop until EV::unloop is called or all watchers stop 52 EV::loop; # loop until EV::unloop is called or all watchers stop
53 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled 53 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
54 EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block 54 EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
55 55
56=head1 DESCRIPTION 56=head1 DESCRIPTION
57 57
58This module provides an interface to libev 58This module provides an interface to libev
59(L<http://software.schmorp.de/pkg/libev.html>). While the documentation 59(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
60below is comprehensive, one might also consult the documentation of libev 60below is comprehensive, one might also consult the documentation of
61itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on 61libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
62watcher semantics or some discussion on the available backends, or how to 62F<perldoc EV::libev>) for more subtle details on watcher semantics or some
63force a specific backend with C<LIBEV_FLAGS>, or just about in any case 63discussion on the available backends, or how to force a specific backend
64because it has much more detailed information. 64with C<LIBEV_FLAGS>, or just about in any case because it has much more
65detailed information.
66
67This module is very fast and scalable. It is actually so fast that you
68can use it through the L<AnyEvent> module, stay portable to other event
69loops (if you don't rely on any watcher types not available through it)
70and still be faster than with any other event loop currently supported in
71Perl.
72
73=head2 MODULE EXPORTS
74
75This module does not export any symbols.
65 76
66=cut 77=cut
67 78
68package EV; 79package EV;
69 80
70use strict; 81use common::sense;
71 82
72BEGIN { 83BEGIN {
73 our $VERSION = '2.0'; 84 our $VERSION = '3.7001';
74 use XSLoader; 85 use XSLoader;
75 XSLoader::load "EV", $VERSION; 86 XSLoader::load "EV", $VERSION;
76} 87}
77 88
78@EV::IO::ISA = 89@EV::IO::ISA =
84@EV::Idle::ISA = 95@EV::Idle::ISA =
85@EV::Prepare::ISA = 96@EV::Prepare::ISA =
86@EV::Check::ISA = 97@EV::Check::ISA =
87@EV::Embed::ISA = 98@EV::Embed::ISA =
88@EV::Fork::ISA = 99@EV::Fork::ISA =
100@EV::Async::ISA =
89 "EV::Watcher"; 101 "EV::Watcher";
90 102
91@EV::Loop::Default::ISA = "EV::Loop"; 103@EV::Loop::Default::ISA = "EV::Loop";
104
105=head1 EVENT LOOPS
106
107EV supports multiple event loops: There is a single "default event loop"
108that can handle everything including signals and child watchers, and any
109number of "dynamic event loops" that can use different backends (with
110various limitations), but no child and signal watchers.
111
112You do not have to do anything to create the default event loop: When
113the module is loaded a suitable backend is selected on the premise of
114selecting a working backend (which for example rules out kqueue on most
115BSDs). Modules should, unless they have "special needs" always use the
116default loop as this is fastest (perl-wise), best supported by other
117modules (e.g. AnyEvent or Coro) and most portable event loop.
118
119For specific programs you can create additional event loops dynamically.
120
121If you want to take advantage of kqueue (which often works properly for
122sockets only) even though the default loop doesn't enable it, you can
123I<embed> a kqueue loop into the default loop: running the default loop
124will then also service the kqueue loop to some extent. See the example in
125the section about embed watchers for an example on how to achieve that.
126
127=over 4
128
129=item $loop = new EV::Loop [$flags]
130
131Create a new event loop as per the specified flags. Please refer to
132the C<ev_loop_new ()> function description in the libev documentation
133(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
134or locally-installed as F<EV::libev> manpage) for more info.
135
136The loop will automatically be destroyed when it is no longer referenced
137by any watcher and the loop object goes out of scope.
138
139If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
140is recommended, as only the default event loop is protected by this
141module. If you I<are> embedding this loop in the default loop, this is not
142necessary, as C<EV::embed> automatically does the right thing on fork.
143
144=item $loop->loop_fork
145
146Must be called after a fork in the child, before entering or continuing
147the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
148this function automatically, at some performance loss (refer to the libev
149documentation).
150
151=item $loop->loop_verify
152
153Calls C<ev_verify> to make internal consistency checks (for debugging
154libev) and abort the program if any data structures were found to be
155corrupted.
156
157=item $loop = EV::default_loop [$flags]
158
159Return the default loop (which is a singleton object). Since this module
160already creates the default loop with default flags, specifying flags here
161will not have any effect unless you destroy the default loop first, which
162isn't supported. So in short: don't do it, and if you break it, you get to
163keep the pieces.
164
165=back
166
92 167
93=head1 BASIC INTERFACE 168=head1 BASIC INTERFACE
94 169
95=over 4 170=over 4
96 171
100throws an exception (with $@ containing the error). The default prints an 175throws an exception (with $@ containing the error). The default prints an
101informative message and continues. 176informative message and continues.
102 177
103If this callback throws an exception it will be silently ignored. 178If this callback throws an exception it will be silently ignored.
104 179
180=item $flags = EV::supported_backends
181
182=item $flags = EV::recommended_backends
183
184=item $flags = EV::embeddable_backends
185
186Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
187instance of EV, the set of recommended backends (supposed to be good) for
188this platform and the set of embeddable backends (see EMBED WATCHERS).
189
190=item EV::sleep $seconds
191
192Block the process for the given number of (fractional) seconds.
193
105=item $time = EV::time 194=item $time = EV::time
106 195
107Returns the current time in (fractional) seconds since the epoch. 196Returns the current time in (fractional) seconds since the epoch.
108 197
109=item $time = EV::now 198=item $time = EV::now
110 199
200=item $time = $loop->now
201
111Returns the time the last event loop iteration has been started. This 202Returns the time the last event loop iteration has been started. This
112is the time that (relative) timers are based on, and refering to it is 203is the time that (relative) timers are based on, and referring to it is
113usually faster then calling EV::time. 204usually faster then calling EV::time.
114 205
115=item $method = EV::method 206=item EV::now_update
116 207
208=item $loop->now_update
209
210Establishes the current time by querying the kernel, updating the time
211returned by C<EV::now> in the progress. This is a costly operation and
212is usually done automatically within C<EV::loop>.
213
214This function is rarely useful, but when some event callback runs for a
215very long time without entering the event loop, updating libev's idea of
216the current time is a good idea.
217
218=item EV::suspend
219
220=item $loop->suspend
221
222=item EV::resume
223
224=item $loop->resume
225
226These two functions suspend and resume a loop, for use when the loop is
227not used for a while and timeouts should not be processed.
228
229A typical use case would be an interactive program such as a game: When
230the user presses C<^Z> to suspend the game and resumes it an hour later it
231would be best to handle timeouts as if no time had actually passed while
232the program was suspended. This can be achieved by calling C<suspend>
233in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
234C<resume> directly afterwards to resume timer processing.
235
236Effectively, all C<timer> watchers will be delayed by the time spend
237between C<suspend> and C<resume>, and all C<periodic> watchers
238will be rescheduled (that is, they will lose any events that would have
239occured while suspended).
240
241After calling C<suspend> you B<must not> call I<any> function on the given
242loop other than C<resume>, and you B<must not> call C<resume>
243without a previous call to C<suspend>.
244
245Calling C<suspend>/C<resume> has the side effect of updating the event
246loop time (see C<now_update>).
247
248=item $backend = EV::backend
249
250=item $backend = $loop->backend
251
117Returns an integer describing the backend used by libev (EV::METHOD_SELECT 252Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
118or EV::METHOD_EPOLL). 253or EV::BACKEND_EPOLL).
119 254
120=item EV::loop [$flags] 255=item EV::loop [$flags]
256
257=item $loop->loop ([$flags])
121 258
122Begin checking for events and calling callbacks. It returns when a 259Begin checking for events and calling callbacks. It returns when a
123callback calls EV::unloop. 260callback calls EV::unloop.
124 261
125The $flags argument can be one of the following: 262The $flags argument can be one of the following:
128 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 265 EV::LOOP_ONESHOT block at most once (wait, but do not loop)
129 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 266 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
130 267
131=item EV::unloop [$how] 268=item EV::unloop [$how]
132 269
270=item $loop->unloop ([$how])
271
133When called with no arguments or an argument of EV::UNLOOP_ONE, makes the 272When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
134innermost call to EV::loop return. 273innermost call to EV::loop return.
135 274
136When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as 275When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
137fast as possible. 276fast as possible.
138 277
139=item $count = EV::loop_count 278=item $count = EV::loop_count
140 279
280=item $count = $loop->loop_count
281
141Return the number of times the event loop has polled for new 282Return the number of times the event loop has polled for new
142events. Sometiems useful as a generation counter. 283events. Sometimes useful as a generation counter.
143 284
144=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 285=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
286
287=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
145 288
146This function rolls together an I/O and a timer watcher for a single 289This function rolls together an I/O and a timer watcher for a single
147one-shot event without the need for managing a watcher object. 290one-shot event without the need for managing a watcher object.
148 291
149If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> 292If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
155If timeout is C<undef> or negative, then there will be no 298If timeout is C<undef> or negative, then there will be no
156timeout. Otherwise a EV::timer with this value will be started. 299timeout. Otherwise a EV::timer with this value will be started.
157 300
158When an error occurs or either the timeout or I/O watcher triggers, then 301When an error occurs or either the timeout or I/O watcher triggers, then
159the callback will be called with the received event set (in general 302the callback will be called with the received event set (in general
160you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>, 303you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
161C<EV::WRITE> and C<EV::TIMEOUT>). 304C<EV::WRITE> and C<EV::TIMEOUT>).
162 305
163EV::once doesn't return anything: the watchers stay active till either 306EV::once doesn't return anything: the watchers stay active till either
164of them triggers, then they will be stopped and freed, and the callback 307of them triggers, then they will be stopped and freed, and the callback
165invoked. 308invoked.
166 309
167=item EV::feed_fd_event ($fd, $revents) 310=item EV::feed_fd_event ($fd, $revents)
168 311
312=item $loop->feed_fd_event ($fd, $revents)
313
169Feed an event on a file descriptor into EV. EV will react to this call as 314Feed an event on a file descriptor into EV. EV will react to this call as
170if the readyness notifications specified by C<$revents> (a combination of 315if the readyness notifications specified by C<$revents> (a combination of
171C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. 316C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
172 317
173=item EV::feed_signal_event ($signal) 318=item EV::feed_signal_event ($signal)
174 319
175Feed a signal event into EV. EV will react to this call as if the signal 320Feed a signal event into EV. EV will react to this call as if the signal
176specified by C<$signal> had occured. 321specified by C<$signal> had occured.
177 322
178=back 323=item EV::set_io_collect_interval $time
179 324
325=item $loop->set_io_collect_interval ($time)
180 326
327=item EV::set_timeout_collect_interval $time
328
329=item $loop->set_timeout_collect_interval ($time)
330
331These advanced functions set the minimum block interval when polling for I/O events and the minimum
332wait interval for timer events. See the libev documentation at
333L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
334(locally installed as F<EV::libev>) for a more detailed discussion.
335
336=item $count = EV::pending_count
337
338=item $count = $loop->pending_count
339
340Returns the number of currently pending watchers.
341
342=item EV::invoke_pending
343
344=item $loop->invoke_pending
345
346Invoke all currently pending watchers.
347
348=back
349
350
181=head2 WATCHER OBJECTS 351=head1 WATCHER OBJECTS
182 352
183A watcher is an object that gets created to record your interest in some 353A watcher is an object that gets created to record your interest in some
184event. For instance, if you want to wait for STDIN to become readable, you 354event. For instance, if you want to wait for STDIN to become readable, you
185would create an EV::io watcher for that: 355would create an EV::io watcher for that:
186 356
187 my $watcher = EV::io *STDIN, EV::READ, sub { 357 my $watcher = EV::io *STDIN, EV::READ, sub {
188 my ($watcher, $revents) = @_; 358 my ($watcher, $revents) = @_;
189 warn "yeah, STDIN should not be readable without blocking!\n" 359 warn "yeah, STDIN should now be readable without blocking!\n"
190 }; 360 };
191 361
192All watchers can be active (waiting for events) or inactive (paused). Only 362All watchers can be active (waiting for events) or inactive (paused). Only
193active watchers will have their callbacks invoked. All callbacks will be 363active watchers will have their callbacks invoked. All callbacks will be
194called with at least two arguments: the watcher and a bitmask of received 364called with at least two arguments: the watcher and a bitmask of received
195events. 365events.
196 366
197Each watcher type has its associated bit in revents, so you can use the 367Each watcher type has its associated bit in revents, so you can use the
198same callback for multiple watchers. The event mask is named after the 368same callback for multiple watchers. The event mask is named after the
199type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 369type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
200EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events 370EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
201(which can set both EV::READ and EV::WRITE bits), and EV::timer (which 371(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
202uses EV::TIMEOUT). 372uses EV::TIMEOUT).
203 373
204In the rare case where one wants to create a watcher but not start it at 374In the rare case where one wants to create a watcher but not start it at
278Feed some events on this watcher into EV. EV will react to this call as if 448Feed some events on this watcher into EV. EV will react to this call as if
279the watcher had received the given C<$revents> mask. 449the watcher had received the given C<$revents> mask.
280 450
281=item $revents = $w->clear_pending 451=item $revents = $w->clear_pending
282 452
283If the watcher is pending, this function returns clears its pending status 453If the watcher is pending, this function clears its pending status and
284and returns its C<$revents> bitset (as if its callback was invoked). If the 454returns its C<$revents> bitset (as if its callback was invoked). If the
285watcher isn't pending it does nothing and returns C<0>. 455watcher isn't pending it does nothing and returns C<0>.
286 456
287=item $previous_state = $w->keepalive ($bool) 457=item $previous_state = $w->keepalive ($bool)
288 458
289Normally, C<EV::loop> will return when there are no active watchers 459Normally, C<EV::loop> will return when there are no active watchers
290(which is a "deadlock" because no progress can be made anymore). This is 460(which is a "deadlock" because no progress can be made anymore). This is
291convinient because it allows you to start your watchers (and your jobs), 461convinient because it allows you to start your watchers (and your jobs),
292call C<EV::loop> once and when it returns you know that all your jobs are 462call C<EV::loop> once and when it returns you know that all your jobs are
293finished (or they forgot to register some watchers for their task :). 463finished (or they forgot to register some watchers for their task :).
294 464
295Sometimes, however, this gets in your way, for example when you the module 465Sometimes, however, this gets in your way, for example when the module
296that calls C<EV::loop> (usually the main program) is not the same module 466that calls C<EV::loop> (usually the main program) is not the same module
297as a long-living watcher (for example a DNS client module written by 467as a long-living watcher (for example a DNS client module written by
298somebody else even). Then you might want any outstanding requests to be 468somebody else even). Then you might want any outstanding requests to be
299handled, but you would not want to keep C<EV::loop> from returning just 469handled, but you would not want to keep C<EV::loop> from returning just
300because you happen to have this long-running UDP port watcher. 470because you happen to have this long-running UDP port watcher.
301 471
302In this case you can clear the keepalive status, which means that even 472In this case you can clear the keepalive status, which means that even
303though your watcher is active, it won't keep C<EV::loop> from returning. 473though your watcher is active, it won't keep C<EV::loop> from returning.
304 474
305The initial value for keepalive is true (enabled), and you cna change it 475The initial value for keepalive is true (enabled), and you can change it
306any time. 476any time.
307 477
308Example: Register an I/O watcher for some UDP socket but do not keep the 478Example: Register an I/O watcher for some UDP socket but do not keep the
309event loop from running just because of that watcher. 479event loop from running just because of that watcher.
310 480
311 my $udp_socket = ... 481 my $udp_socket = ...
312 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 482 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
313 $udp_watcher->keepalive (0); 483 $udp_watcher->keepalive (0);
314 484
315=back 485=item $loop = $w->loop
316 486
487Return the loop that this watcher is attached to.
317 488
489=back
490
491
318=head2 WATCHER TYPES 492=head1 WATCHER TYPES
319 493
320Each of the following subsections describes a single watcher type. 494Each of the following subsections describes a single watcher type.
321 495
322=head3 I/O WATCHERS - is this file descriptor readable or writable? 496=head3 I/O WATCHERS - is this file descriptor readable or writable?
323 497
324=over 4 498=over 4
325 499
326=item $w = EV::io $fileno_or_fh, $eventmask, $callback 500=item $w = EV::io $fileno_or_fh, $eventmask, $callback
327 501
328=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 502=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
503
504=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
505
506=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
329 507
330As long as the returned watcher object is alive, call the C<$callback> 508As long as the returned watcher object is alive, call the C<$callback>
331when at least one of events specified in C<$eventmask> occurs. 509when at least one of events specified in C<$eventmask> occurs.
332 510
333The $eventmask can be one or more of these constants ORed together: 511The $eventmask can be one or more of these constants ORed together:
362=over 4 540=over 4
363 541
364=item $w = EV::timer $after, $repeat, $callback 542=item $w = EV::timer $after, $repeat, $callback
365 543
366=item $w = EV::timer_ns $after, $repeat, $callback 544=item $w = EV::timer_ns $after, $repeat, $callback
545
546=item $w = $loop->timer ($after, $repeat, $callback)
547
548=item $w = $loop->timer_ns ($after, $repeat, $callback)
367 549
368Calls the callback after C<$after> seconds (which may be fractional). If 550Calls the callback after C<$after> seconds (which may be fractional). If
369C<$repeat> is non-zero, the timer will be restarted (with the $repeat 551C<$repeat> is non-zero, the timer will be restarted (with the $repeat
370value as $after) after the callback returns. 552value as $after) after the callback returns.
371 553
412=over 4 594=over 4
413 595
414=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback 596=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
415 597
416=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 598=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
599
600=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
601
602=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
417 603
418Similar to EV::timer, but is not based on relative timeouts but on 604Similar to EV::timer, but is not based on relative timeouts but on
419absolute times. Apart from creating "simple" timers that trigger "at" the 605absolute times. Apart from creating "simple" timers that trigger "at" the
420specified time, it can also be used for non-drifting absolute timers and 606specified time, it can also be used for non-drifting absolute timers and
421more complex, cron-like, setups that are not adversely affected by time 607more complex, cron-like, setups that are not adversely affected by time
431This time simply fires at the wallclock time C<$at> and doesn't repeat. It 617This time simply fires at the wallclock time C<$at> and doesn't repeat. It
432will not adjust when a time jump occurs, that is, if it is to be run 618will not adjust when a time jump occurs, that is, if it is to be run
433at January 1st 2011 then it will run when the system time reaches or 619at January 1st 2011 then it will run when the system time reaches or
434surpasses this time. 620surpasses this time.
435 621
436=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 622=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
437 623
438In this mode the watcher will always be scheduled to time out at the 624In this mode the watcher will always be scheduled to time out at the
439next C<$at + N * $interval> time (for some integer N) and then repeat, 625next C<$at + N * $interval> time (for some integer N) and then repeat,
440regardless of any time jumps. 626regardless of any time jumps.
441 627
459time the periodic watcher gets scheduled, the reschedule callback 645time the periodic watcher gets scheduled, the reschedule callback
460($reschedule_cb) will be called with the watcher as first, and the current 646($reschedule_cb) will be called with the watcher as first, and the current
461time as second argument. 647time as second argument.
462 648
463I<This callback MUST NOT stop or destroy this or any other periodic 649I<This callback MUST NOT stop or destroy this or any other periodic
464watcher, ever>. If you need to stop it, return 1e30 and stop it 650watcher, ever, and MUST NOT call any event loop functions or methods>. If
465afterwards. 651you need to stop it, return 1e30 and stop it afterwards. You may create
652and start a C<EV::prepare> watcher for this task.
466 653
467It must return the next time to trigger, based on the passed time value 654It must return the next time to trigger, based on the passed time value
468(that is, the lowest time value larger than to the second argument). It 655(that is, the lowest time value larger than or equal to to the second
469will usually be called just before the callback will be triggered, but 656argument). It will usually be called just before the callback will be
470might be called at other times, too. 657triggered, but might be called at other times, too.
471 658
472This can be used to create very complex timers, such as a timer that 659This can be used to create very complex timers, such as a timer that
473triggers on each midnight, local time (actually 24 hours after the last 660triggers on each midnight, local time (actually 24 hours after the last
474midnight, to keep the example simple. If you know a way to do it correctly 661midnight, to keep the example simple. If you know a way to do it correctly
475in about the same space (without requiring elaborate modules), drop me a 662in about the same space (without requiring elaborate modules), drop me a
542 729
543=head3 CHILD WATCHERS - watch out for process status changes 730=head3 CHILD WATCHERS - watch out for process status changes
544 731
545=over 4 732=over 4
546 733
547=item $w = EV::child $pid, $callback 734=item $w = EV::child $pid, $trace, $callback
548 735
549=item $w = EV::child_ns $pid, $callback 736=item $w = EV::child_ns $pid, $trace, $callback
550 737
738=item $w = $loop->child ($pid, $trace, $callback)
739
740=item $w = $loop->child_ns ($pid, $trace, $callback)
741
551Call the callback when a status change for pid C<$pid> (or any pid if 742Call the callback when a status change for pid C<$pid> (or any pid
552C<$pid> is 0) has been received. More precisely: when the process receives 743if C<$pid> is 0) has been received (a status change happens when the
744process terminates or is killed, or, when trace is true, additionally when
745it is stopped or continued). More precisely: when the process receives
553a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all 746a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
554changed/zombie children and call the callback. 747changed/zombie children and call the callback.
555 748
556It is valid (and fully supported) to install a child watcher after a child 749It is valid (and fully supported) to install a child watcher after a child
557has exited but before the event loop has started its next iteration (for 750has exited but before the event loop has started its next iteration (for
564You can have as many pid watchers per pid as you want, they will all be 757You can have as many pid watchers per pid as you want, they will all be
565called. 758called.
566 759
567The C<child_ns> variant doesn't start (activate) the newly created watcher. 760The C<child_ns> variant doesn't start (activate) the newly created watcher.
568 761
569=item $w->set ($pid) 762=item $w->set ($pid, $trace)
570 763
571Reconfigures the watcher, see the constructor above for details. Can be called at 764Reconfigures the watcher, see the constructor above for details. Can be called at
572any time. 765any time.
573 766
574=item $current_pid = $w->pid 767=item $current_pid = $w->pid
575 768
576=item $old_pid = $w->pid ($new_pid)
577
578Returns the previously set process id and optionally set a new one. 769Returns the previously set process id and optionally set a new one.
579 770
580=item $exit_status = $w->rstatus 771=item $exit_status = $w->rstatus
581 772
582Return the exit/wait status (as returned by waitpid, see the waitpid entry 773Return the exit/wait status (as returned by waitpid, see the waitpid entry
595=over 4 786=over 4
596 787
597=item $w = EV::stat $path, $interval, $callback 788=item $w = EV::stat $path, $interval, $callback
598 789
599=item $w = EV::stat_ns $path, $interval, $callback 790=item $w = EV::stat_ns $path, $interval, $callback
791
792=item $w = $loop->stat ($path, $interval, $callback)
793
794=item $w = $loop->stat_ns ($path, $interval, $callback)
600 795
601Call the callback when a file status change has been detected on 796Call the callback when a file status change has been detected on
602C<$path>. The C<$path> does not need to exist, changing from "path exists" 797C<$path>. The C<$path> does not need to exist, changing from "path exists"
603to "path does not exist" is a status change like any other. 798to "path does not exist" is a status change like any other.
604 799
674=over 4 869=over 4
675 870
676=item $w = EV::idle $callback 871=item $w = EV::idle $callback
677 872
678=item $w = EV::idle_ns $callback 873=item $w = EV::idle_ns $callback
874
875=item $w = $loop->idle ($callback)
876
877=item $w = $loop->idle_ns ($callback)
679 878
680Call the callback when there are no other pending watchers of the same or 879Call the callback when there are no other pending watchers of the same or
681higher priority (excluding check, prepare and other idle watchers of the 880higher priority (excluding check, prepare and other idle watchers of the
682same or lower priority, of course). They are called idle watchers because 881same or lower priority, of course). They are called idle watchers because
683when the watcher is the highest priority pending event in the process, the 882when the watcher is the highest priority pending event in the process, the
706 905
707=item $w = EV::prepare $callback 906=item $w = EV::prepare $callback
708 907
709=item $w = EV::prepare_ns $callback 908=item $w = EV::prepare_ns $callback
710 909
910=item $w = $loop->prepare ($callback)
911
912=item $w = $loop->prepare_ns ($callback)
913
711Call the callback just before the process would block. You can still 914Call the callback just before the process would block. You can still
712create/modify any watchers at this point. 915create/modify any watchers at this point.
713 916
714See the EV::check watcher, below, for explanations and an example. 917See the EV::check watcher, below, for explanations and an example.
715 918
723=over 4 926=over 4
724 927
725=item $w = EV::check $callback 928=item $w = EV::check $callback
726 929
727=item $w = EV::check_ns $callback 930=item $w = EV::check_ns $callback
931
932=item $w = $loop->check ($callback)
933
934=item $w = $loop->check_ns ($callback)
728 935
729Call the callback just after the process wakes up again (after it has 936Call the callback just after the process wakes up again (after it has
730gathered events), but before any other callbacks have been invoked. 937gathered events), but before any other callbacks have been invoked.
731 938
732This is used to integrate other event-based software into the EV 939This is used to integrate other event-based software into the EV
767 # make the dispatcher handle any new stuff 974 # make the dispatcher handle any new stuff
768 ... not shown 975 ... not shown
769 }; 976 };
770 977
771The callbacks of the created watchers will not be called as the watchers 978The callbacks of the created watchers will not be called as the watchers
772are destroyed before this cna happen (remember EV::check gets called 979are destroyed before this can happen (remember EV::check gets called
773first). 980first).
774 981
775The C<check_ns> variant doesn't start (activate) the newly created watcher. 982The C<check_ns> variant doesn't start (activate) the newly created watcher.
776 983
777=back 984=back
787 994
788=item $w = EV::fork $callback 995=item $w = EV::fork $callback
789 996
790=item $w = EV::fork_ns $callback 997=item $w = EV::fork_ns $callback
791 998
999=item $w = $loop->fork ($callback)
1000
1001=item $w = $loop->fork_ns ($callback)
1002
792Call the callback before the event loop is resumed in the child process 1003Call the callback before the event loop is resumed in the child process
793after a fork. 1004after a fork.
794 1005
795The C<fork_ns> variant doesn't start (activate) the newly created watcher. 1006The C<fork_ns> variant doesn't start (activate) the newly created watcher.
1007
1008=back
1009
1010
1011=head3 EMBED WATCHERS - when one backend isn't enough...
1012
1013This is a rather advanced watcher type that lets you embed one event loop
1014into another (currently only IO events are supported in the embedded
1015loop, other types of watchers might be handled in a delayed or incorrect
1016fashion and must not be used).
1017
1018See the libev documentation at
1019L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
1020(locally installed as F<EV::libev>) for more details.
1021
1022In short, this watcher is most useful on BSD systems without working
1023kqueue to still be able to handle a large number of sockets:
1024
1025 my $socket_loop;
1026
1027 # check wether we use SELECT or POLL _and_ KQUEUE is supported
1028 if (
1029 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
1030 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
1031 ) {
1032 # use kqueue for sockets
1033 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
1034 }
1035
1036 # use the default loop otherwise
1037 $socket_loop ||= EV::default_loop;
1038
1039=over 4
1040
1041=item $w = EV::embed $otherloop[, $callback]
1042
1043=item $w = EV::embed_ns $otherloop[, $callback]
1044
1045=item $w = $loop->embed ($otherloop[, $callback])
1046
1047=item $w = $loop->embed_ns ($otherloop[, $callback])
1048
1049Call the callback when the embedded event loop (C<$otherloop>) has any
1050I/O activity. The C<$callback> is optional: if it is missing, then the
1051embedded event loop will be managed automatically (which is recommended),
1052otherwise you have to invoke C<sweep> yourself.
1053
1054The C<embed_ns> variant doesn't start (activate) the newly created watcher.
1055
1056=back
1057
1058=head3 ASYNC WATCHERS - how to wake up another event loop
1059
1060Async watchers are provided by EV, but have little use in perl directly,
1061as perl neither supports threads running in parallel nor direct access to
1062signal handlers or other contexts where they could be of value.
1063
1064It is, however, possible to use them from the XS level.
1065
1066Please see the libev documentation for further details.
1067
1068=over 4
1069
1070=item $w = EV::async $callback
1071
1072=item $w = EV::async_ns $callback
1073
1074=item $w->send
1075
1076=item $bool = $w->async_pending
796 1077
797=back 1078=back
798 1079
799 1080
800=head1 PERL SIGNALS 1081=head1 PERL SIGNALS
811to be called on every event loop iteration by installing a C<EV::check> 1092to be called on every event loop iteration by installing a C<EV::check>
812watcher: 1093watcher:
813 1094
814 my $async_check = EV::check sub { }; 1095 my $async_check = EV::check sub { };
815 1096
816This ensures that perl shortly gets into control for a short time, and 1097This ensures that perl gets into control for a short time to handle any
817also ensures slower overall operation. 1098pending signals, and also ensures (slightly) slower overall operation.
818 1099
819=head1 THREADS 1100=head1 ITHREADS
820 1101
821Threads are not supported by this module in any way. Perl pseudo-threads 1102Ithreads are not supported by this module in any way. Perl pseudo-threads
822is evil stuff and must die. As soon as Perl gains real threads I will work 1103is evil stuff and must die. Real threads as provided by Coro are fully
823on thread support for it. 1104supported (and enhanced support is available via L<Coro::EV>).
824 1105
825=head1 FORK 1106=head1 FORK
826 1107
827Most of the "improved" event delivering mechanisms of modern operating 1108Most of the "improved" event delivering mechanisms of modern operating
828systems have quite a few problems with fork(2) (to put it bluntly: it is 1109systems have quite a few problems with fork(2) (to put it bluntly: it is
850 1131
8511; 11321;
852 1133
853=head1 SEE ALSO 1134=head1 SEE ALSO
854 1135
855L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as 1136L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
856event loop), L<Coro::EV> (efficient coroutines with EV). 1137event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
1138coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1139event-loop agnostic and portable event driven programming.
857 1140
858=head1 AUTHOR 1141=head1 AUTHOR
859 1142
860 Marc Lehmann <schmorp@schmorp.de> 1143 Marc Lehmann <schmorp@schmorp.de>
861 http://home.schmorp.de/ 1144 http://home.schmorp.de/
862 1145
863=cut 1146=cut
864 1147

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