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Revision 1.67 by root, Sun Dec 9 02:14:23 2007 UTC vs.
Revision 1.114 by root, Wed Apr 15 19:35:53 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
81no warnings;
70use strict; 82use strict;
71 83
72BEGIN { 84BEGIN {
73 our $VERSION = '1.72'; 85 our $VERSION = '3.53';
74 use XSLoader; 86 use XSLoader;
75 XSLoader::load "EV", $VERSION; 87 XSLoader::load "EV", $VERSION;
76} 88}
77 89
78@EV::IO::ISA = 90@EV::IO::ISA =
… …
84@EV::Idle::ISA = 96@EV::Idle::ISA =
85@EV::Prepare::ISA = 97@EV::Prepare::ISA =
86@EV::Check::ISA = 98@EV::Check::ISA =
87@EV::Embed::ISA = 99@EV::Embed::ISA =
88@EV::Fork::ISA = 100@EV::Fork::ISA =
101@EV::Async::ISA =
89 "EV::Watcher"; 102 "EV::Watcher";
103
104@EV::Loop::Default::ISA = "EV::Loop";
105
106=head1 EVENT LOOPS
107
108EV supports multiple event loops: There is a single "default event loop"
109that can handle everything including signals and child watchers, and any
110number of "dynamic event loops" that can use different backends (with
111various limitations), but no child and signal watchers.
112
113You do not have to do anything to create the default event loop: When
114the module is loaded a suitable backend is selected on the premise of
115selecting a working backend (which for example rules out kqueue on most
116BSDs). Modules should, unless they have "special needs" always use the
117default loop as this is fastest (perl-wise), best supported by other
118modules (e.g. AnyEvent or Coro) and most portable event loop.
119
120For specific programs you can create additional event loops dynamically.
121
122If you want to take advantage of kqueue (which often works properly for
123sockets only) even though the default loop doesn't enable it, you can
124I<embed> a kqueue loop into the default loop: running the default loop
125will then also service the kqueue loop to some extent. See the example in
126the section about embed watchers for an example on how to achieve that.
127
128=over 4
129
130=item $loop = new EV::Loop [$flags]
131
132Create a new event loop as per the specified flags. Please refer to
133the C<ev_loop_new ()> function description in the libev documentation
134(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
135or locally-installed as F<EV::libev> manpage) for more info.
136
137The loop will automatically be destroyed when it is no longer referenced
138by any watcher and the loop object goes out of scope.
139
140If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
141is recommended, as only the default event loop is protected by this
142module. If you I<are> embedding this loop in the default loop, this is not
143necessary, as C<EV::embed> automatically does the right thing on fork.
144
145=item $loop->loop_fork
146
147Must be called after a fork in the child, before entering or continuing
148the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
149this function automatically, at some performance loss (refer to the libev
150documentation).
151
152=item $loop->loop_verify
153
154Calls C<ev_verify> to make internal consistency checks (for debugging
155libev) and abort the program if any data structures were found to be
156corrupted.
157
158=item $loop = EV::default_loop [$flags]
159
160Return the default loop (which is a singleton object). Since this module
161already creates the default loop with default flags, specifying flags here
162will not have any effect unless you destroy the default loop first, which
163isn't supported. So in short: don't do it, and if you break it, you get to
164keep the pieces.
165
166=back
167
90 168
91=head1 BASIC INTERFACE 169=head1 BASIC INTERFACE
92 170
93=over 4 171=over 4
94 172
… …
98throws an exception (with $@ containing the error). The default prints an 176throws an exception (with $@ containing the error). The default prints an
99informative message and continues. 177informative message and continues.
100 178
101If this callback throws an exception it will be silently ignored. 179If this callback throws an exception it will be silently ignored.
102 180
181=item $flags = EV::supported_backends
182
183=item $flags = EV::recommended_backends
184
185=item $flags = EV::embeddable_backends
186
187Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
188instance of EV, the set of recommended backends (supposed to be good) for
189this platform and the set of embeddable backends (see EMBED WATCHERS).
190
191=item EV::sleep $seconds
192
193Block the process for the given number of (fractional) seconds.
194
103=item $time = EV::time 195=item $time = EV::time
104 196
105Returns the current time in (fractional) seconds since the epoch. 197Returns the current time in (fractional) seconds since the epoch.
106 198
107=item $time = EV::now 199=item $time = EV::now
108 200
201=item $time = $loop->now
202
109Returns the time the last event loop iteration has been started. This 203Returns 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 204is the time that (relative) timers are based on, and referring to it is
111usually faster then calling EV::time. 205usually faster then calling EV::time.
112 206
113=item $method = EV::method 207=item EV::now_update
114 208
209=item $loop->now_update
210
211Establishes the current time by querying the kernel, updating the time
212returned by C<EV::now> in the progress. This is a costly operation and
213is usually done automatically within C<EV::loop>.
214
215This function is rarely useful, but when some event callback runs for a
216very long time without entering the event loop, updating libev's idea of
217the current time is a good idea.
218
219=item EV::suspend
220
221=item $loop->suspend
222
223=item EV::resume
224
225=item $loop->resume
226
227These two functions suspend and resume a loop, for use when the loop is
228not used for a while and timeouts should not be processed.
229
230A typical use case would be an interactive program such as a game: When
231the user presses C<^Z> to suspend the game and resumes it an hour later it
232would be best to handle timeouts as if no time had actually passed while
233the program was suspended. This can be achieved by calling C<suspend>
234in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
235C<resume> directly afterwards to resume timer processing.
236
237Effectively, all C<timer> watchers will be delayed by the time spend
238between C<suspend> and C<resume>, and all C<periodic> watchers
239will be rescheduled (that is, they will lose any events that would have
240occured while suspended).
241
242After calling C<suspend> you B<must not> call I<any> function on the given
243loop other than C<resume>, and you B<must not> call C<resume>
244without a previous call to C<suspend>.
245
246Calling C<suspend>/C<resume> has the side effect of updating the event
247loop time (see C<now_update>).
248
249=item $backend = EV::backend
250
251=item $backend = $loop->backend
252
115Returns an integer describing the backend used by libev (EV::METHOD_SELECT 253Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
116or EV::METHOD_EPOLL). 254or EV::BACKEND_EPOLL).
117 255
118=item EV::loop [$flags] 256=item EV::loop [$flags]
257
258=item $loop->loop ([$flags])
119 259
120Begin checking for events and calling callbacks. It returns when a 260Begin checking for events and calling callbacks. It returns when a
121callback calls EV::unloop. 261callback calls EV::unloop.
122 262
123The $flags argument can be one of the following: 263The $flags argument can be one of the following:
… …
126 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 266 EV::LOOP_ONESHOT block at most once (wait, but do not loop)
127 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 267 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
128 268
129=item EV::unloop [$how] 269=item EV::unloop [$how]
130 270
271=item $loop->unloop ([$how])
272
131When called with no arguments or an argument of EV::UNLOOP_ONE, makes the 273When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
132innermost call to EV::loop return. 274innermost call to EV::loop return.
133 275
134When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as 276When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
135fast as possible. 277fast as possible.
136 278
137=item $count = EV::loop_count 279=item $count = EV::loop_count
138 280
281=item $count = $loop->loop_count
282
139Return the number of times the event loop has polled for new 283Return the number of times the event loop has polled for new
140events. Sometiems useful as a generation counter. 284events. Sometimes useful as a generation counter.
141 285
142=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 286=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
287
288=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
143 289
144This function rolls together an I/O and a timer watcher for a single 290This function rolls together an I/O and a timer watcher for a single
145one-shot event without the need for managing a watcher object. 291one-shot event without the need for managing a watcher object.
146 292
147If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> 293If 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 299If timeout is C<undef> or negative, then there will be no
154timeout. Otherwise a EV::timer with this value will be started. 300timeout. Otherwise a EV::timer with this value will be started.
155 301
156When an error occurs or either the timeout or I/O watcher triggers, then 302When 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 303the 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>, 304you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
159C<EV::WRITE> and C<EV::TIMEOUT>). 305C<EV::WRITE> and C<EV::TIMEOUT>).
160 306
161EV::once doesn't return anything: the watchers stay active till either 307EV::once doesn't return anything: the watchers stay active till either
162of them triggers, then they will be stopped and freed, and the callback 308of them triggers, then they will be stopped and freed, and the callback
163invoked. 309invoked.
164 310
165=item EV::feed_fd_event ($fd, $revents) 311=item EV::feed_fd_event ($fd, $revents)
166 312
313=item $loop->feed_fd_event ($fd, $revents)
314
167Feed an event on a file descriptor into EV. EV will react to this call as 315Feed an event on a file descriptor into EV. EV will react to this call as
168if the readyness notifications specified by C<$revents> (a combination of 316if the readyness notifications specified by C<$revents> (a combination of
169C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. 317C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
170 318
171=item EV::feed_signal_event ($signal) 319=item EV::feed_signal_event ($signal)
172 320
173Feed a signal event into EV. EV will react to this call as if the signal 321Feed a signal event into EV. EV will react to this call as if the signal
174specified by C<$signal> had occured. 322specified by C<$signal> had occured.
175 323
176=back 324=item EV::set_io_collect_interval $time
177 325
326=item $loop->set_io_collect_interval ($time)
178 327
328=item EV::set_timeout_collect_interval $time
329
330=item $loop->set_timeout_collect_interval ($time)
331
332These advanced functions set the minimum block interval when polling for I/O events and the minimum
333wait interval for timer events. See the libev documentation at
334L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
335(locally installed as F<EV::libev>) for a more detailed discussion.
336
337=back
338
339
179=head2 WATCHER OBJECTS 340=head1 WATCHER OBJECTS
180 341
181A watcher is an object that gets created to record your interest in some 342A 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 343event. For instance, if you want to wait for STDIN to become readable, you
183would create an EV::io watcher for that: 344would create an EV::io watcher for that:
184 345
185 my $watcher = EV::io *STDIN, EV::READ, sub { 346 my $watcher = EV::io *STDIN, EV::READ, sub {
186 my ($watcher, $revents) = @_; 347 my ($watcher, $revents) = @_;
187 warn "yeah, STDIN should not be readable without blocking!\n" 348 warn "yeah, STDIN should now be readable without blocking!\n"
188 }; 349 };
189 350
190All watchers can be active (waiting for events) or inactive (paused). Only 351All watchers can be active (waiting for events) or inactive (paused). Only
191active watchers will have their callbacks invoked. All callbacks will be 352active watchers will have their callbacks invoked. All callbacks will be
192called with at least two arguments: the watcher and a bitmask of received 353called with at least two arguments: the watcher and a bitmask of received
193events. 354events.
194 355
195Each watcher type has its associated bit in revents, so you can use the 356Each watcher type has its associated bit in revents, so you can use the
196same callback for multiple watchers. The event mask is named after the 357same callback for multiple watchers. The event mask is named after the
197type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 358type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
198EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events 359EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
199(which can set both EV::READ and EV::WRITE bits), and EV::timer (which 360(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
200uses EV::TIMEOUT). 361uses EV::TIMEOUT).
201 362
202In the rare case where one wants to create a watcher but not start it at 363In the rare case where one wants to create a watcher but not start it at
… …
276Feed some events on this watcher into EV. EV will react to this call as if 437Feed some events on this watcher into EV. EV will react to this call as if
277the watcher had received the given C<$revents> mask. 438the watcher had received the given C<$revents> mask.
278 439
279=item $revents = $w->clear_pending 440=item $revents = $w->clear_pending
280 441
281If the watcher is pending, this function returns clears its pending status 442If the watcher is pending, this function clears its pending status and
282and returns its C<$revents> bitset (as if its callback was invoked). If the 443returns its C<$revents> bitset (as if its callback was invoked). If the
283watcher isn't pending it does nothing and returns C<0>. 444watcher isn't pending it does nothing and returns C<0>.
284 445
285=item $previous_state = $w->keepalive ($bool) 446=item $previous_state = $w->keepalive ($bool)
286 447
287Normally, C<EV::loop> will return when there are no active watchers 448Normally, 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 449(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), 450convinient 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 451call 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 :). 452finished (or they forgot to register some watchers for their task :).
292 453
293Sometimes, however, this gets in your way, for example when you the module 454Sometimes, 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 455that 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 456as a long-living watcher (for example a DNS client module written by
296somebody else even). Then you might want any outstanding requests to be 457somebody 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 458handled, but you would not want to keep C<EV::loop> from returning just
298because you happen to have this long-running UDP port watcher. 459because you happen to have this long-running UDP port watcher.
299 460
300In this case you can clear the keepalive status, which means that even 461In this case you can clear the keepalive status, which means that even
301though your watcher is active, it won't keep C<EV::loop> from returning. 462though your watcher is active, it won't keep C<EV::loop> from returning.
302 463
303The initial value for keepalive is true (enabled), and you cna change it 464The initial value for keepalive is true (enabled), and you can change it
304any time. 465any time.
305 466
306Example: Register an I/O watcher for some UDP socket but do not keep the 467Example: Register an I/O watcher for some UDP socket but do not keep the
307event loop from running just because of that watcher. 468event loop from running just because of that watcher.
308 469
309 my $udp_socket = ... 470 my $udp_socket = ...
310 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 471 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
311 $udp_watcher->keepalive (0); 472 $udp_watcher->keepalive (0);
312 473
313=back 474=item $loop = $w->loop
314 475
476Return the loop that this watcher is attached to.
315 477
478=back
479
480
316=head2 WATCHER TYPES 481=head1 WATCHER TYPES
317 482
318Each of the following subsections describes a single watcher type. 483Each of the following subsections describes a single watcher type.
319 484
320=head3 I/O WATCHERS - is this file descriptor readable or writable? 485=head3 I/O WATCHERS - is this file descriptor readable or writable?
321 486
322=over 4 487=over 4
323 488
324=item $w = EV::io $fileno_or_fh, $eventmask, $callback 489=item $w = EV::io $fileno_or_fh, $eventmask, $callback
325 490
326=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 491=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
492
493=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
494
495=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
327 496
328As long as the returned watcher object is alive, call the C<$callback> 497As long as the returned watcher object is alive, call the C<$callback>
329when at least one of events specified in C<$eventmask> occurs. 498when at least one of events specified in C<$eventmask> occurs.
330 499
331The $eventmask can be one or more of these constants ORed together: 500The $eventmask can be one or more of these constants ORed together:
… …
360=over 4 529=over 4
361 530
362=item $w = EV::timer $after, $repeat, $callback 531=item $w = EV::timer $after, $repeat, $callback
363 532
364=item $w = EV::timer_ns $after, $repeat, $callback 533=item $w = EV::timer_ns $after, $repeat, $callback
534
535=item $w = $loop->timer ($after, $repeat, $callback)
536
537=item $w = $loop->timer_ns ($after, $repeat, $callback)
365 538
366Calls the callback after C<$after> seconds (which may be fractional). If 539Calls the callback after C<$after> seconds (which may be fractional). If
367C<$repeat> is non-zero, the timer will be restarted (with the $repeat 540C<$repeat> is non-zero, the timer will be restarted (with the $repeat
368value as $after) after the callback returns. 541value as $after) after the callback returns.
369 542
… …
410=over 4 583=over 4
411 584
412=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback 585=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
413 586
414=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 587=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
588
589=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
590
591=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
415 592
416Similar to EV::timer, but is not based on relative timeouts but on 593Similar to EV::timer, but is not based on relative timeouts but on
417absolute times. Apart from creating "simple" timers that trigger "at" the 594absolute times. Apart from creating "simple" timers that trigger "at" the
418specified time, it can also be used for non-drifting absolute timers and 595specified time, it can also be used for non-drifting absolute timers and
419more complex, cron-like, setups that are not adversely affected by time 596more complex, cron-like, setups that are not adversely affected by time
… …
429This time simply fires at the wallclock time C<$at> and doesn't repeat. It 606This time simply fires at the wallclock time C<$at> and doesn't repeat. It
430will not adjust when a time jump occurs, that is, if it is to be run 607will not adjust when a time jump occurs, that is, if it is to be run
431at January 1st 2011 then it will run when the system time reaches or 608at January 1st 2011 then it will run when the system time reaches or
432surpasses this time. 609surpasses this time.
433 610
434=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 611=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
435 612
436In this mode the watcher will always be scheduled to time out at the 613In this mode the watcher will always be scheduled to time out at the
437next C<$at + N * $interval> time (for some integer N) and then repeat, 614next C<$at + N * $interval> time (for some integer N) and then repeat,
438regardless of any time jumps. 615regardless of any time jumps.
439 616
… …
457time the periodic watcher gets scheduled, the reschedule callback 634time the periodic watcher gets scheduled, the reschedule callback
458($reschedule_cb) will be called with the watcher as first, and the current 635($reschedule_cb) will be called with the watcher as first, and the current
459time as second argument. 636time as second argument.
460 637
461I<This callback MUST NOT stop or destroy this or any other periodic 638I<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 639watcher, ever, and MUST NOT call any event loop functions or methods>. If
463afterwards. 640you need to stop it, return 1e30 and stop it afterwards. You may create
641and start a C<EV::prepare> watcher for this task.
464 642
465It must return the next time to trigger, based on the passed time value 643It 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 644(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 645argument). It will usually be called just before the callback will be
468might be called at other times, too. 646triggered, but might be called at other times, too.
469 647
470This can be used to create very complex timers, such as a timer that 648This 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 649triggers 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 650midnight, 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 651in about the same space (without requiring elaborate modules), drop me a
… …
494 672
495=item $w->again 673=item $w->again
496 674
497Simply stops and starts the watcher again. 675Simply stops and starts the watcher again.
498 676
677=item $time = $w->at
678
679Return the time that the watcher is expected to trigger next.
680
499=back 681=back
500 682
501 683
502=head3 SIGNAL WATCHERS - signal me when a signal gets signalled! 684=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
503 685
… …
536 718
537=head3 CHILD WATCHERS - watch out for process status changes 719=head3 CHILD WATCHERS - watch out for process status changes
538 720
539=over 4 721=over 4
540 722
541=item $w = EV::child $pid, $callback 723=item $w = EV::child $pid, $trace, $callback
542 724
543=item $w = EV::child_ns $pid, $callback 725=item $w = EV::child_ns $pid, $trace, $callback
544 726
727=item $w = $loop->child ($pid, $trace, $callback)
728
729=item $w = $loop->child_ns ($pid, $trace, $callback)
730
545Call the callback when a status change for pid C<$pid> (or any pid if 731Call 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 732if C<$pid> is 0) has been received (a status change happens when the
733process terminates or is killed, or, when trace is true, additionally when
734it is stopped or continued). More precisely: when the process receives
547a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all 735a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
548changed/zombie children and call the callback. 736changed/zombie children and call the callback.
549 737
550It is valid (and fully supported) to install a child watcher after a child 738It 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 739has 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 746You can have as many pid watchers per pid as you want, they will all be
559called. 747called.
560 748
561The C<child_ns> variant doesn't start (activate) the newly created watcher. 749The C<child_ns> variant doesn't start (activate) the newly created watcher.
562 750
563=item $w->set ($pid) 751=item $w->set ($pid, $trace)
564 752
565Reconfigures the watcher, see the constructor above for details. Can be called at 753Reconfigures the watcher, see the constructor above for details. Can be called at
566any time. 754any time.
567 755
568=item $current_pid = $w->pid 756=item $current_pid = $w->pid
569 757
570=item $old_pid = $w->pid ($new_pid)
571
572Returns the previously set process id and optionally set a new one. 758Returns the previously set process id and optionally set a new one.
573 759
574=item $exit_status = $w->rstatus 760=item $exit_status = $w->rstatus
575 761
576Return the exit/wait status (as returned by waitpid, see the waitpid entry 762Return the exit/wait status (as returned by waitpid, see the waitpid entry
… …
589=over 4 775=over 4
590 776
591=item $w = EV::stat $path, $interval, $callback 777=item $w = EV::stat $path, $interval, $callback
592 778
593=item $w = EV::stat_ns $path, $interval, $callback 779=item $w = EV::stat_ns $path, $interval, $callback
780
781=item $w = $loop->stat ($path, $interval, $callback)
782
783=item $w = $loop->stat_ns ($path, $interval, $callback)
594 784
595Call the callback when a file status change has been detected on 785Call the callback when a file status change has been detected on
596C<$path>. The C<$path> does not need to exist, changing from "path exists" 786C<$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. 787to "path does not exist" is a status change like any other.
598 788
… …
668=over 4 858=over 4
669 859
670=item $w = EV::idle $callback 860=item $w = EV::idle $callback
671 861
672=item $w = EV::idle_ns $callback 862=item $w = EV::idle_ns $callback
863
864=item $w = $loop->idle ($callback)
865
866=item $w = $loop->idle_ns ($callback)
673 867
674Call the callback when there are no other pending watchers of the same or 868Call the callback when there are no other pending watchers of the same or
675higher priority (excluding check, prepare and other idle watchers of the 869higher priority (excluding check, prepare and other idle watchers of the
676same or lower priority, of course). They are called idle watchers because 870same or lower priority, of course). They are called idle watchers because
677when the watcher is the highest priority pending event in the process, the 871when the watcher is the highest priority pending event in the process, the
… …
700 894
701=item $w = EV::prepare $callback 895=item $w = EV::prepare $callback
702 896
703=item $w = EV::prepare_ns $callback 897=item $w = EV::prepare_ns $callback
704 898
899=item $w = $loop->prepare ($callback)
900
901=item $w = $loop->prepare_ns ($callback)
902
705Call the callback just before the process would block. You can still 903Call the callback just before the process would block. You can still
706create/modify any watchers at this point. 904create/modify any watchers at this point.
707 905
708See the EV::check watcher, below, for explanations and an example. 906See the EV::check watcher, below, for explanations and an example.
709 907
… …
717=over 4 915=over 4
718 916
719=item $w = EV::check $callback 917=item $w = EV::check $callback
720 918
721=item $w = EV::check_ns $callback 919=item $w = EV::check_ns $callback
920
921=item $w = $loop->check ($callback)
922
923=item $w = $loop->check_ns ($callback)
722 924
723Call the callback just after the process wakes up again (after it has 925Call the callback just after the process wakes up again (after it has
724gathered events), but before any other callbacks have been invoked. 926gathered events), but before any other callbacks have been invoked.
725 927
726This is used to integrate other event-based software into the EV 928This is used to integrate other event-based software into the EV
… …
761 # make the dispatcher handle any new stuff 963 # make the dispatcher handle any new stuff
762 ... not shown 964 ... not shown
763 }; 965 };
764 966
765The callbacks of the created watchers will not be called as the watchers 967The callbacks of the created watchers will not be called as the watchers
766are destroyed before this cna happen (remember EV::check gets called 968are destroyed before this can happen (remember EV::check gets called
767first). 969first).
768 970
769The C<check_ns> variant doesn't start (activate) the newly created watcher. 971The C<check_ns> variant doesn't start (activate) the newly created watcher.
770 972
771=back 973=back
… …
781 983
782=item $w = EV::fork $callback 984=item $w = EV::fork $callback
783 985
784=item $w = EV::fork_ns $callback 986=item $w = EV::fork_ns $callback
785 987
988=item $w = $loop->fork ($callback)
989
990=item $w = $loop->fork_ns ($callback)
991
786Call the callback before the event loop is resumed in the child process 992Call the callback before the event loop is resumed in the child process
787after a fork. 993after a fork.
788 994
789The C<fork_ns> variant doesn't start (activate) the newly created watcher. 995The C<fork_ns> variant doesn't start (activate) the newly created watcher.
996
997=back
998
999
1000=head3 EMBED WATCHERS - when one backend isn't enough...
1001
1002This is a rather advanced watcher type that lets you embed one event loop
1003into another (currently only IO events are supported in the embedded
1004loop, other types of watchers might be handled in a delayed or incorrect
1005fashion and must not be used).
1006
1007See the libev documentation at
1008L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
1009(locally installed as F<EV::libev>) for more details.
1010
1011In short, this watcher is most useful on BSD systems without working
1012kqueue to still be able to handle a large number of sockets:
1013
1014 my $socket_loop;
1015
1016 # check wether we use SELECT or POLL _and_ KQUEUE is supported
1017 if (
1018 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
1019 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
1020 ) {
1021 # use kqueue for sockets
1022 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
1023 }
1024
1025 # use the default loop otherwise
1026 $socket_loop ||= EV::default_loop;
1027
1028=over 4
1029
1030=item $w = EV::embed $otherloop[, $callback]
1031
1032=item $w = EV::embed_ns $otherloop[, $callback]
1033
1034=item $w = $loop->embed ($otherloop[, $callback])
1035
1036=item $w = $loop->embed_ns ($otherloop[, $callback])
1037
1038Call the callback when the embedded event loop (C<$otherloop>) has any
1039I/O activity. The C<$callback> is optional: if it is missing, then the
1040embedded event loop will be managed automatically (which is recommended),
1041otherwise you have to invoke C<sweep> yourself.
1042
1043The C<embed_ns> variant doesn't start (activate) the newly created watcher.
1044
1045=back
1046
1047=head3 ASYNC WATCHERS - how to wake up another event loop
1048
1049Async watchers are provided by EV, but have little use in perl directly, as perl
1050neither supports threads nor direct access to signal handlers or other
1051contexts where they could be of value.
1052
1053It is, however, possible to use them from the XS level.
1054
1055Please see the libev documentation for further details.
1056
1057=over 4
1058
1059=item $w = EV::async $callback
1060
1061=item $w = EV::async_ns $callback
1062
1063=item $w->send
1064
1065=item $bool = $w->async_pending
790 1066
791=back 1067=back
792 1068
793 1069
794=head1 PERL SIGNALS 1070=head1 PERL SIGNALS
… …
805to be called on every event loop iteration by installing a C<EV::check> 1081to be called on every event loop iteration by installing a C<EV::check>
806watcher: 1082watcher:
807 1083
808 my $async_check = EV::check sub { }; 1084 my $async_check = EV::check sub { };
809 1085
810This ensures that perl shortly gets into control for a short time, and 1086This ensures that perl gets into control for a short time to handle any
811also ensures slower overall operation. 1087pending signals, and also ensures (slightly) slower overall operation.
812 1088
813=head1 THREADS 1089=head1 THREADS
814 1090
815Threads are not supported by this module in any way. Perl pseudo-threads 1091Threads 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 1092is evil stuff and must die. As soon as Perl gains real threads I will work
… …
838our $DIED = sub { 1114our $DIED = sub {
839 warn "EV: error in callback (ignoring): $@"; 1115 warn "EV: error in callback (ignoring): $@";
840}; 1116};
841 1117
842default_loop 1118default_loop
843 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; 1119 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
844 1120
8451; 11211;
846 1122
847=head1 SEE ALSO 1123=head1 SEE ALSO
848 1124
849L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as 1125L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
850event loop), L<Coro::EV> (efficient coroutines with EV). 1126event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
1127coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1128event-loop agnostic and portable event driven programming.
851 1129
852=head1 AUTHOR 1130=head1 AUTHOR
853 1131
854 Marc Lehmann <schmorp@schmorp.de> 1132 Marc Lehmann <schmorp@schmorp.de>
855 http://home.schmorp.de/ 1133 http://home.schmorp.de/
856 1134
857=cut 1135=cut
858 1136

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