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Revision 1.62 by root, Fri Dec 7 18:09:38 2007 UTC vs.
Revision 1.126 by root, Tue Mar 16 17:11:48 2010 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 = '1.7'; 84 our $VERSION = '4.00';
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
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
167
91=head1 BASIC INTERFACE 168=head1 BASIC INTERFACE
92 169
93=over 4 170=over 4
94 171
95=item $EV::DIED 172=item $EV::DIED
96 173
97Must contain a reference to a function that is called when a callback 174Must contain a reference to a function that is called when a callback
98throws an exception (with $@ containing thr error). The default prints an 175throws an exception (with $@ containing the error). The default prints an
99informative message and continues. 176informative message and continues.
100 177
101If this callback throws an exception it will be silently ignored. 178If this callback throws an exception it will be silently ignored.
102 179
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
103=item $time = EV::time 194=item $time = EV::time
104 195
105Returns the current time in (fractional) seconds since the epoch. 196Returns the current time in (fractional) seconds since the epoch.
106 197
107=item $time = EV::now 198=item $time = EV::now
108 199
200=item $time = $loop->now
201
109Returns the time the last event loop iteration has been started. This 202Returns 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 203is the time that (relative) timers are based on, and referring to it is
111usually faster then calling EV::time. 204usually faster then calling EV::time.
112 205
113=item $method = EV::method 206=item EV::now_update
114 207
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 = $loop->backend
251
115Returns an integer describing the backend used by libev (EV::METHOD_SELECT 252Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
116or EV::METHOD_EPOLL). 253or EV::BACKEND_EPOLL).
117 254
118=item EV::loop [$flags] 255=item EV::loop [$flags]
256
257=item $loop->loop ([$flags])
119 258
120Begin checking for events and calling callbacks. It returns when a 259Begin checking for events and calling callbacks. It returns when a
121callback calls EV::unloop. 260callback calls EV::unloop.
122 261
123The $flags argument can be one of the following: 262The $flags argument can be one of the following:
… …
126 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 265 EV::LOOP_ONESHOT block at most once (wait, but do not loop)
127 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 266 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
128 267
129=item EV::unloop [$how] 268=item EV::unloop [$how]
130 269
270=item $loop->unloop ([$how])
271
131When 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
132innermost call to EV::loop return. 273innermost call to EV::loop return.
133 274
134When 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
135fast as possible. 276fast as possible.
136 277
137=item $count = EV::loop_count 278=item $count = EV::loop_count
138 279
280=item $count = $loop->loop_count
281
139Return the number of times the event loop has polled for new 282Return the number of times the event loop has polled for new
140events. Sometiems useful as a generation counter. 283events. Sometimes useful as a generation counter.
141 284
142=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))
143 288
144This 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
145one-shot event without the need for managing a watcher object. 290one-shot event without the need for managing a watcher object.
146 291
147If 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>
… …
153If timeout is C<undef> or negative, then there will be no 298If timeout is C<undef> or negative, then there will be no
154timeout. Otherwise a EV::timer with this value will be started. 299timeout. Otherwise a EV::timer with this value will be started.
155 300
156When 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
157the callback will be called with the received event set (in general 302the 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>, 303you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
159C<EV::WRITE> and C<EV::TIMEOUT>). 304C<EV::WRITE> and C<EV::TIMER>).
160 305
161EV::once doesn't return anything: the watchers stay active till either 306EV::once doesn't return anything: the watchers stay active till either
162of 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
163invoked. 308invoked.
164 309
165=back 310=item EV::feed_fd_event ($fd, $revents)
166 311
312=item $loop->feed_fd_event ($fd, $revents)
313
314Feed an event on a file descriptor into EV. EV will react to this call as
315if the readyness notifications specified by C<$revents> (a combination of
316C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
317
318=item EV::feed_signal_event ($signal)
319
320Feed a signal event into EV. EV will react to this call as if the signal
321specified by C<$signal> had occured.
322
323=item EV::set_io_collect_interval $time
324
325=item $loop->set_io_collect_interval ($time)
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
167=head2 WATCHER OBJECTS 351=head1 WATCHER OBJECTS
168 352
169A 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
170event. 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
171would create an EV::io watcher for that: 355would create an EV::io watcher for that:
172 356
173 my $watcher = EV::io *STDIN, EV::READ, sub { 357 my $watcher = EV::io *STDIN, EV::READ, sub {
174 my ($watcher, $revents) = @_; 358 my ($watcher, $revents) = @_;
175 warn "yeah, STDIN should not be readable without blocking!\n" 359 warn "yeah, STDIN should now be readable without blocking!\n"
176 }; 360 };
177 361
178All watchers can be active (waiting for events) or inactive (paused). Only 362All watchers can be active (waiting for events) or inactive (paused). Only
179active watchers will have their callbacks invoked. All callbacks will be 363active watchers will have their callbacks invoked. All callbacks will be
180called 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
181events. 365events.
182 366
183Each 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
184same callback for multiple watchers. The event mask is named after the 368same callback for multiple watchers. The event mask is named after the
185type, 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,
186EV::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
187(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).
188uses EV::TIMEOUT).
189 372
190In the rare case where one wants to create a watcher but not start it at 373In the rare case where one wants to create a watcher but not start it at
191the same time, each constructor has a variant with a trailing C<_ns> in 374the same time, each constructor has a variant with a trailing C<_ns> in
192its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. 375its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
193 376
… …
253The default priority of any newly-created watcher is 0. 436The default priority of any newly-created watcher is 0.
254 437
255Note that the priority semantics have not yet been fleshed out and are 438Note that the priority semantics have not yet been fleshed out and are
256subject to almost certain change. 439subject to almost certain change.
257 440
258=item $w->trigger ($revents) 441=item $w->invoke ($revents)
259 442
260Call the callback *now* with the given event mask. 443Call the callback *now* with the given event mask.
444
445=item $w->feed_event ($revents)
446
447Feed some events on this watcher into EV. EV will react to this call as if
448the watcher had received the given C<$revents> mask.
449
450=item $revents = $w->clear_pending
451
452If the watcher is pending, this function clears its pending status and
453returns its C<$revents> bitset (as if its callback was invoked). If the
454watcher isn't pending it does nothing and returns C<0>.
261 455
262=item $previous_state = $w->keepalive ($bool) 456=item $previous_state = $w->keepalive ($bool)
263 457
264Normally, C<EV::loop> will return when there are no active watchers 458Normally, C<EV::loop> will return when there are no active watchers
265(which is a "deadlock" because no progress can be made anymore). This is 459(which is a "deadlock" because no progress can be made anymore). This is
266convinient because it allows you to start your watchers (and your jobs), 460convenient because it allows you to start your watchers (and your jobs),
267call C<EV::loop> once and when it returns you know that all your jobs are 461call C<EV::loop> once and when it returns you know that all your jobs are
268finished (or they forgot to register some watchers for their task :). 462finished (or they forgot to register some watchers for their task :).
269 463
270Sometimes, however, this gets in your way, for example when you the module 464Sometimes, however, this gets in your way, for example when the module
271that calls C<EV::loop> (usually the main program) is not the same module 465that calls C<EV::loop> (usually the main program) is not the same module
272as a long-living watcher (for example a DNS client module written by 466as a long-living watcher (for example a DNS client module written by
273somebody else even). Then you might want any outstanding requests to be 467somebody else even). Then you might want any outstanding requests to be
274handled, but you would not want to keep C<EV::loop> from returning just 468handled, but you would not want to keep C<EV::loop> from returning just
275because you happen to have this long-running UDP port watcher. 469because you happen to have this long-running UDP port watcher.
276 470
277In this case you can clear the keepalive status, which means that even 471In this case you can clear the keepalive status, which means that even
278though your watcher is active, it won't keep C<EV::loop> from returning. 472though your watcher is active, it won't keep C<EV::loop> from returning.
279 473
280The initial value for keepalive is true (enabled), and you cna change it 474The initial value for keepalive is true (enabled), and you can change it
281any time. 475any time.
282 476
283Example: Register an I/O watcher for some UDP socket but do not keep the 477Example: Register an I/O watcher for some UDP socket but do not keep the
284event loop from running just because of that watcher. 478event loop from running just because of that watcher.
285 479
286 my $udp_socket = ... 480 my $udp_socket = ...
287 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 481 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
288 $udp_watcher->keepalive (0); 482 $udp_watcher->keepalive (0);
289 483
290=back 484=item $loop = $w->loop
291 485
486Return the loop that this watcher is attached to.
292 487
488=back
489
490
293=head2 WATCHER TYPES 491=head1 WATCHER TYPES
294 492
295Each of the following subsections describes a single watcher type. 493Each of the following subsections describes a single watcher type.
296 494
297=head3 I/O WATCHERS - is this file descriptor readable or writable? 495=head3 I/O WATCHERS - is this file descriptor readable or writable?
298 496
299=over 4 497=over 4
300 498
301=item $w = EV::io $fileno_or_fh, $eventmask, $callback 499=item $w = EV::io $fileno_or_fh, $eventmask, $callback
302 500
303=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 501=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
502
503=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
504
505=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
304 506
305As long as the returned watcher object is alive, call the C<$callback> 507As long as the returned watcher object is alive, call the C<$callback>
306when at least one of events specified in C<$eventmask> occurs. 508when at least one of events specified in C<$eventmask> occurs.
307 509
308The $eventmask can be one or more of these constants ORed together: 510The $eventmask can be one or more of these constants ORed together:
… …
337=over 4 539=over 4
338 540
339=item $w = EV::timer $after, $repeat, $callback 541=item $w = EV::timer $after, $repeat, $callback
340 542
341=item $w = EV::timer_ns $after, $repeat, $callback 543=item $w = EV::timer_ns $after, $repeat, $callback
544
545=item $w = $loop->timer ($after, $repeat, $callback)
546
547=item $w = $loop->timer_ns ($after, $repeat, $callback)
342 548
343Calls the callback after C<$after> seconds (which may be fractional). If 549Calls the callback after C<$after> seconds (which may be fractional). If
344C<$repeat> is non-zero, the timer will be restarted (with the $repeat 550C<$repeat> is non-zero, the timer will be restarted (with the $repeat
345value as $after) after the callback returns. 551value as $after) after the callback returns.
346 552
… …
387=over 4 593=over 4
388 594
389=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback 595=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
390 596
391=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 597=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
598
599=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
600
601=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
392 602
393Similar to EV::timer, but is not based on relative timeouts but on 603Similar to EV::timer, but is not based on relative timeouts but on
394absolute times. Apart from creating "simple" timers that trigger "at" the 604absolute times. Apart from creating "simple" timers that trigger "at" the
395specified time, it can also be used for non-drifting absolute timers and 605specified time, it can also be used for non-drifting absolute timers and
396more complex, cron-like, setups that are not adversely affected by time 606more complex, cron-like, setups that are not adversely affected by time
… …
406This time simply fires at the wallclock time C<$at> and doesn't repeat. It 616This time simply fires at the wallclock time C<$at> and doesn't repeat. It
407will not adjust when a time jump occurs, that is, if it is to be run 617will not adjust when a time jump occurs, that is, if it is to be run
408at January 1st 2011 then it will run when the system time reaches or 618at January 1st 2011 then it will run when the system time reaches or
409surpasses this time. 619surpasses this time.
410 620
411=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 621=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
412 622
413In this mode the watcher will always be scheduled to time out at the 623In this mode the watcher will always be scheduled to time out at the
414next C<$at + N * $interval> time (for some integer N) and then repeat, 624next C<$at + N * $interval> time (for some integer N) and then repeat,
415regardless of any time jumps. 625regardless of any time jumps.
416 626
… …
434time the periodic watcher gets scheduled, the reschedule callback 644time the periodic watcher gets scheduled, the reschedule callback
435($reschedule_cb) will be called with the watcher as first, and the current 645($reschedule_cb) will be called with the watcher as first, and the current
436time as second argument. 646time as second argument.
437 647
438I<This callback MUST NOT stop or destroy this or any other periodic 648I<This callback MUST NOT stop or destroy this or any other periodic
439watcher, ever>. If you need to stop it, return 1e30 and stop it 649watcher, ever, and MUST NOT call any event loop functions or methods>. If
440afterwards. 650you need to stop it, return 1e30 and stop it afterwards. You may create
651and start a C<EV::prepare> watcher for this task.
441 652
442It must return the next time to trigger, based on the passed time value 653It must return the next time to trigger, based on the passed time value
443(that is, the lowest time value larger than to the second argument). It 654(that is, the lowest time value larger than or equal to to the second
444will usually be called just before the callback will be triggered, but 655argument). It will usually be called just before the callback will be
445might be called at other times, too. 656triggered, but might be called at other times, too.
446 657
447This can be used to create very complex timers, such as a timer that 658This can be used to create very complex timers, such as a timer that
448triggers on each midnight, local time (actually 24 hours after the last 659triggers on each midnight, local time (actually 24 hours after the last
449midnight, to keep the example simple. If you know a way to do it correctly 660midnight, to keep the example simple. If you know a way to do it correctly
450in about the same space (without requiring elaborate modules), drop me a 661in about the same space (without requiring elaborate modules), drop me a
… …
471 682
472=item $w->again 683=item $w->again
473 684
474Simply stops and starts the watcher again. 685Simply stops and starts the watcher again.
475 686
687=item $time = $w->at
688
689Return the time that the watcher is expected to trigger next.
690
476=back 691=back
477 692
478 693
479=head3 SIGNAL WATCHERS - signal me when a signal gets signalled! 694=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
480 695
481=over 4 696=over 4
482 697
483=item $w = EV::signal $signal, $callback 698=item $w = EV::signal $signal, $callback
484 699
485=item $w = EV::signal_ns $signal, $callback 700=item $w = EV::signal_ns $signal, $callback
701
702=item $w = $loop->signal ($signal, $callback)
703
704=item $w = $loop->signal_ns ($signal, $callback)
486 705
487Call the callback when $signal is received (the signal can be specified by 706Call the callback when $signal is received (the signal can be specified by
488number or by name, just as with C<kill> or C<%SIG>). 707number or by name, just as with C<kill> or C<%SIG>).
708
709Only one event loop can grab a given signal - attempting to grab the same
710signal from two EV loops will crash the program immediately or cause data
711corruption.
489 712
490EV will grab the signal for the process (the kernel only allows one 713EV will grab the signal for the process (the kernel only allows one
491component to receive a signal at a time) when you start a signal watcher, 714component to receive a signal at a time) when you start a signal watcher,
492and removes it again when you stop it. Perl does the same when you 715and removes it again when you stop it. Perl does the same when you
493add/remove callbacks to C<%SIG>, so watch out. 716add/remove callbacks to C<%SIG>, so watch out.
… …
513 736
514=head3 CHILD WATCHERS - watch out for process status changes 737=head3 CHILD WATCHERS - watch out for process status changes
515 738
516=over 4 739=over 4
517 740
518=item $w = EV::child $pid, $callback 741=item $w = EV::child $pid, $trace, $callback
519 742
520=item $w = EV::child_ns $pid, $callback 743=item $w = EV::child_ns $pid, $trace, $callback
521 744
745=item $w = $loop->child ($pid, $trace, $callback)
746
747=item $w = $loop->child_ns ($pid, $trace, $callback)
748
522Call the callback when a status change for pid C<$pid> (or any pid if 749Call the callback when a status change for pid C<$pid> (or any pid
523C<$pid> is 0) has been received. More precisely: when the process receives 750if C<$pid> is 0) has been received (a status change happens when the
751process terminates or is killed, or, when trace is true, additionally when
752it is stopped or continued). More precisely: when the process receives
524a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all 753a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
525changed/zombie children and call the callback. 754changed/zombie children and call the callback.
526 755
527It is valid (and fully supported) to install a child watcher after a child 756It is valid (and fully supported) to install a child watcher after a child
528has exited but before the event loop has started its next iteration (for 757has exited but before the event loop has started its next iteration (for
… …
535You can have as many pid watchers per pid as you want, they will all be 764You can have as many pid watchers per pid as you want, they will all be
536called. 765called.
537 766
538The C<child_ns> variant doesn't start (activate) the newly created watcher. 767The C<child_ns> variant doesn't start (activate) the newly created watcher.
539 768
540=item $w->set ($pid) 769=item $w->set ($pid, $trace)
541 770
542Reconfigures the watcher, see the constructor above for details. Can be called at 771Reconfigures the watcher, see the constructor above for details. Can be called at
543any time. 772any time.
544 773
545=item $current_pid = $w->pid 774=item $current_pid = $w->pid
546 775
547=item $old_pid = $w->pid ($new_pid)
548
549Returns the previously set process id and optionally set a new one. 776Returns the previously set process id and optionally set a new one.
550 777
551=item $exit_status = $w->rstatus 778=item $exit_status = $w->rstatus
552 779
553Return the exit/wait status (as returned by waitpid, see the waitpid entry 780Return the exit/wait status (as returned by waitpid, see the waitpid entry
… …
566=over 4 793=over 4
567 794
568=item $w = EV::stat $path, $interval, $callback 795=item $w = EV::stat $path, $interval, $callback
569 796
570=item $w = EV::stat_ns $path, $interval, $callback 797=item $w = EV::stat_ns $path, $interval, $callback
798
799=item $w = $loop->stat ($path, $interval, $callback)
800
801=item $w = $loop->stat_ns ($path, $interval, $callback)
571 802
572Call the callback when a file status change has been detected on 803Call the callback when a file status change has been detected on
573C<$path>. The C<$path> does not need to exist, changing from "path exists" 804C<$path>. The C<$path> does not need to exist, changing from "path exists"
574to "path does not exist" is a status change like any other. 805to "path does not exist" is a status change like any other.
575 806
… …
645=over 4 876=over 4
646 877
647=item $w = EV::idle $callback 878=item $w = EV::idle $callback
648 879
649=item $w = EV::idle_ns $callback 880=item $w = EV::idle_ns $callback
881
882=item $w = $loop->idle ($callback)
883
884=item $w = $loop->idle_ns ($callback)
650 885
651Call the callback when there are no other pending watchers of the same or 886Call the callback when there are no other pending watchers of the same or
652higher priority (excluding check, prepare and other idle watchers of the 887higher priority (excluding check, prepare and other idle watchers of the
653same or lower priority, of course). They are called idle watchers because 888same or lower priority, of course). They are called idle watchers because
654when the watcher is the highest priority pending event in the process, the 889when the watcher is the highest priority pending event in the process, the
… …
677 912
678=item $w = EV::prepare $callback 913=item $w = EV::prepare $callback
679 914
680=item $w = EV::prepare_ns $callback 915=item $w = EV::prepare_ns $callback
681 916
917=item $w = $loop->prepare ($callback)
918
919=item $w = $loop->prepare_ns ($callback)
920
682Call the callback just before the process would block. You can still 921Call the callback just before the process would block. You can still
683create/modify any watchers at this point. 922create/modify any watchers at this point.
684 923
685See the EV::check watcher, below, for explanations and an example. 924See the EV::check watcher, below, for explanations and an example.
686 925
… …
694=over 4 933=over 4
695 934
696=item $w = EV::check $callback 935=item $w = EV::check $callback
697 936
698=item $w = EV::check_ns $callback 937=item $w = EV::check_ns $callback
938
939=item $w = $loop->check ($callback)
940
941=item $w = $loop->check_ns ($callback)
699 942
700Call the callback just after the process wakes up again (after it has 943Call the callback just after the process wakes up again (after it has
701gathered events), but before any other callbacks have been invoked. 944gathered events), but before any other callbacks have been invoked.
702 945
703This is used to integrate other event-based software into the EV 946This is used to integrate other event-based software into the EV
… …
738 # make the dispatcher handle any new stuff 981 # make the dispatcher handle any new stuff
739 ... not shown 982 ... not shown
740 }; 983 };
741 984
742The callbacks of the created watchers will not be called as the watchers 985The callbacks of the created watchers will not be called as the watchers
743are destroyed before this cna happen (remember EV::check gets called 986are destroyed before this can happen (remember EV::check gets called
744first). 987first).
745 988
746The C<check_ns> variant doesn't start (activate) the newly created watcher. 989The C<check_ns> variant doesn't start (activate) the newly created watcher.
747 990
748=back 991=back
… …
758 1001
759=item $w = EV::fork $callback 1002=item $w = EV::fork $callback
760 1003
761=item $w = EV::fork_ns $callback 1004=item $w = EV::fork_ns $callback
762 1005
1006=item $w = $loop->fork ($callback)
1007
1008=item $w = $loop->fork_ns ($callback)
1009
763Call the callback before the event loop is resumed in the child process 1010Call the callback before the event loop is resumed in the child process
764after a fork. 1011after a fork.
765 1012
766The C<fork_ns> variant doesn't start (activate) the newly created watcher. 1013The C<fork_ns> variant doesn't start (activate) the newly created watcher.
1014
1015=back
1016
1017
1018=head3 EMBED WATCHERS - when one backend isn't enough...
1019
1020This is a rather advanced watcher type that lets you embed one event loop
1021into another (currently only IO events are supported in the embedded
1022loop, other types of watchers might be handled in a delayed or incorrect
1023fashion and must not be used).
1024
1025See the libev documentation at
1026L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
1027(locally installed as F<EV::libev>) for more details.
1028
1029In short, this watcher is most useful on BSD systems without working
1030kqueue to still be able to handle a large number of sockets:
1031
1032 my $socket_loop;
1033
1034 # check wether we use SELECT or POLL _and_ KQUEUE is supported
1035 if (
1036 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
1037 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
1038 ) {
1039 # use kqueue for sockets
1040 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
1041 }
1042
1043 # use the default loop otherwise
1044 $socket_loop ||= EV::default_loop;
1045
1046=over 4
1047
1048=item $w = EV::embed $otherloop[, $callback]
1049
1050=item $w = EV::embed_ns $otherloop[, $callback]
1051
1052=item $w = $loop->embed ($otherloop[, $callback])
1053
1054=item $w = $loop->embed_ns ($otherloop[, $callback])
1055
1056Call the callback when the embedded event loop (C<$otherloop>) has any
1057I/O activity. The C<$callback> is optional: if it is missing, then the
1058embedded event loop will be managed automatically (which is recommended),
1059otherwise you have to invoke C<sweep> yourself.
1060
1061The C<embed_ns> variant doesn't start (activate) the newly created watcher.
1062
1063=back
1064
1065=head3 ASYNC WATCHERS - how to wake up another event loop
1066
1067Async watchers are provided by EV, but have little use in perl directly,
1068as perl neither supports threads running in parallel nor direct access to
1069signal handlers or other contexts where they could be of value.
1070
1071It is, however, possible to use them from the XS level.
1072
1073Please see the libev documentation for further details.
1074
1075=over 4
1076
1077=item $w = EV::async $callback
1078
1079=item $w = EV::async_ns $callback
1080
1081=item $w->send
1082
1083=item $bool = $w->async_pending
767 1084
768=back 1085=back
769 1086
770 1087
771=head1 PERL SIGNALS 1088=head1 PERL SIGNALS
… …
782to be called on every event loop iteration by installing a C<EV::check> 1099to be called on every event loop iteration by installing a C<EV::check>
783watcher: 1100watcher:
784 1101
785 my $async_check = EV::check sub { }; 1102 my $async_check = EV::check sub { };
786 1103
787This ensures that perl shortly gets into control for a short time, and 1104This ensures that perl gets into control for a short time to handle any
788also ensures slower overall operation. 1105pending signals, and also ensures (slightly) slower overall operation.
789 1106
790=head1 THREADS 1107=head1 ITHREADS
791 1108
792Threads are not supported by this module in any way. Perl pseudo-threads 1109Ithreads are not supported by this module in any way. Perl pseudo-threads
793is evil stuff and must die. As soon as Perl gains real threads I will work 1110is evil stuff and must die. Real threads as provided by Coro are fully
794on thread support for it. 1111supported (and enhanced support is available via L<Coro::EV>).
795 1112
796=head1 FORK 1113=head1 FORK
797 1114
798Most of the "improved" event delivering mechanisms of modern operating 1115Most of the "improved" event delivering mechanisms of modern operating
799systems have quite a few problems with fork(2) (to put it bluntly: it is 1116systems have quite a few problems with fork(2) (to put it bluntly: it is
… …
815our $DIED = sub { 1132our $DIED = sub {
816 warn "EV: error in callback (ignoring): $@"; 1133 warn "EV: error in callback (ignoring): $@";
817}; 1134};
818 1135
819default_loop 1136default_loop
820 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; 1137 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
821 1138
8221; 11391;
823 1140
824=head1 SEE ALSO 1141=head1 SEE ALSO
825 1142
826L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as 1143L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
827event loop), L<Coro::EV> (efficient coroutines with EV). 1144event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
1145coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1146event-loop agnostic and portable event driven programming.
828 1147
829=head1 AUTHOR 1148=head1 AUTHOR
830 1149
831 Marc Lehmann <schmorp@schmorp.de> 1150 Marc Lehmann <schmorp@schmorp.de>
832 http://home.schmorp.de/ 1151 http://home.schmorp.de/
833 1152
834=cut 1153=cut
835 1154

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