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Revision 1.82 by root, Fri Jan 25 15:45:08 2008 UTC vs.
Revision 1.141 by root, Tue Oct 22 10:43:05 2013 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 $w = EV::child 666, 0, sub {
41 my ($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::run; # 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::run EV::RUN_ONCE; # 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::run EV::RUN_NOWAIT; # try to handle same events, but do not block
55
56=head1 BEFORE YOU START USING THIS MODULE
57
58If you only need timer, I/O, signal, child and idle watchers and not the
59advanced functionality of this module, consider using L<AnyEvent> instead,
60specifically the simplified API described in L<AE>.
61
62When used with EV as backend, the L<AE> API is as fast as the native L<EV>
63API, but your programs/modules will still run with many other event loops.
55 64
56=head1 DESCRIPTION 65=head1 DESCRIPTION
57 66
58This module provides an interface to libev 67This module provides an interface to libev
59(L<http://software.schmorp.de/pkg/libev.html>). While the documentation 68(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
60below is comprehensive, one might also consult the documentation of libev 69below is comprehensive, one might also consult the documentation of
61itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on 70libev 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 71F<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 72discussion on the available backends, or how to force a specific backend
64because it has much more detailed information. 73with C<LIBEV_FLAGS>, or just about in any case because it has much more
74detailed information.
75
76This module is very fast and scalable. It is actually so fast that you
77can use it through the L<AnyEvent> module, stay portable to other event
78loops (if you don't rely on any watcher types not available through it)
79and still be faster than with any other event loop currently supported in
80Perl.
81
82=head2 PORTING FROM EV 3.X to 4.X
83
84EV version 4 introduces a number of incompatible changes summarised
85here. According to the depreciation strategy used by libev, there is a
86compatibility layer in place so programs should continue to run unchanged
87(the XS interface lacks this layer, so programs using that one need to be
88updated).
89
90This compatibility layer will be switched off in some future release.
91
92All changes relevant to Perl are renames of symbols, functions and
93methods:
94
95 EV::loop => EV::run
96 EV::LOOP_NONBLOCK => EV::RUN_NOWAIT
97 EV::LOOP_ONESHOT => EV::RUN_ONCE
98
99 EV::unloop => EV::break
100 EV::UNLOOP_CANCEL => EV::BREAK_CANCEL
101 EV::UNLOOP_ONE => EV::BREAK_ONE
102 EV::UNLOOP_ALL => EV::BREAK_ALL
103
104 EV::TIMEOUT => EV::TIMER
105
106 EV::loop_count => EV::iteration
107 EV::loop_depth => EV::depth
108 EV::loop_verify => EV::verify
109
110The loop object methods corresponding to the functions above have been
111similarly renamed.
112
113=head2 MODULE EXPORTS
114
115This module does not export any symbols.
65 116
66=cut 117=cut
67 118
68package EV; 119package EV;
69 120
70use strict; 121use common::sense;
71 122
72BEGIN { 123BEGIN {
73 our $VERSION = '2.01'; 124 our $VERSION = '4.15';
74 use XSLoader; 125 use XSLoader;
126 local $^W = 0; # avoid spurious warning
75 XSLoader::load "EV", $VERSION; 127 XSLoader::load "EV", $VERSION;
76} 128}
77 129
78@EV::IO::ISA = 130@EV::IO::ISA =
79@EV::Timer::ISA = 131@EV::Timer::ISA =
… …
84@EV::Idle::ISA = 136@EV::Idle::ISA =
85@EV::Prepare::ISA = 137@EV::Prepare::ISA =
86@EV::Check::ISA = 138@EV::Check::ISA =
87@EV::Embed::ISA = 139@EV::Embed::ISA =
88@EV::Fork::ISA = 140@EV::Fork::ISA =
141@EV::Async::ISA =
89 "EV::Watcher"; 142 "EV::Watcher";
90 143
91@EV::Loop::Default::ISA = "EV::Loop"; 144@EV::Loop::Default::ISA = "EV::Loop";
92 145
93=head1 EVENT LOOPS 146=head1 EVENT LOOPS
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104default loop as this is fastest (perl-wise), best supported by other 157default loop as this is fastest (perl-wise), best supported by other
105modules (e.g. AnyEvent or Coro) and most portable event loop. 158modules (e.g. AnyEvent or Coro) and most portable event loop.
106 159
107For specific programs you can create additional event loops dynamically. 160For specific programs you can create additional event loops dynamically.
108 161
109=over 4 162If you want to take advantage of kqueue (which often works properly for
163sockets only) even though the default loop doesn't enable it, you can
164I<embed> a kqueue loop into the default loop: running the default loop
165will then also service the kqueue loop to some extent. See the example in
166the section about embed watchers for an example on how to achieve that.
110 167
168=over 4
169
111=item $loop = new EV::loop [$flags] 170=item $loop = new EV::Loop [$flags]
112 171
113Create a new event loop as per the specified flags. Please refer to the 172Create a new event loop as per the specified flags. Please refer to
114C<ev_loop_new ()> function description in the libev documentation 173the C<ev_loop_new ()> function description in the libev documentation
115(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>) 174(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
116for more info. 175or locally-installed as F<EV::libev> manpage) for more info.
117 176
118The loop will automatically be destroyed when it is no longer referenced 177The loop will automatically be destroyed when it is no longer referenced
119by any watcher and the loop object goes out of scope. 178by any watcher and the loop object goes out of scope.
120 179
121Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop 180If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
122is protected by this module. 181is recommended, as only the default event loop is protected by this
182module. If you I<are> embedding this loop in the default loop, this is not
183necessary, as C<EV::embed> automatically does the right thing on fork.
123 184
124=item $loop->loop_fork 185=item $loop->loop_fork
125 186
126Must be called after a fork in the child, before entering or continuing 187Must be called after a fork in the child, before entering or continuing
127the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls 188the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
128this fucntion automatically, at some performance loss (refer to the libev 189this function automatically, at some performance loss (refer to the libev
129documentation). 190documentation).
130 191
192=item $loop->verify
193
194Calls C<ev_verify> to make internal consistency checks (for debugging
195libev) and abort the program if any data structures were found to be
196corrupted.
197
131=item $loop = EV::default_loop [$flags] 198=item $loop = EV::default_loop [$flags]
132 199
133Return the default loop (which is a singleton object). 200Return the default loop (which is a singleton object). Since this module
201already creates the default loop with default flags, specifying flags here
202will not have any effect unless you destroy the default loop first, which
203isn't supported. So in short: don't do it, and if you break it, you get to
204keep the pieces.
134 205
135=back 206=back
136 207
137 208
138=head1 BASIC INTERFACE 209=head1 BASIC INTERFACE
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168=item $time = EV::now 239=item $time = EV::now
169 240
170=item $time = $loop->now 241=item $time = $loop->now
171 242
172Returns the time the last event loop iteration has been started. This 243Returns the time the last event loop iteration has been started. This
173is the time that (relative) timers are based on, and refering to it is 244is the time that (relative) timers are based on, and referring to it is
174usually faster then calling EV::time. 245usually faster then calling EV::time.
175 246
247=item EV::now_update
248
249=item $loop->now_update
250
251Establishes the current time by querying the kernel, updating the time
252returned by C<EV::now> in the progress. This is a costly operation and
253is usually done automatically within C<EV::loop>.
254
255This function is rarely useful, but when some event callback runs for a
256very long time without entering the event loop, updating libev's idea of
257the current time is a good idea.
258
259=item EV::suspend
260
261=item $loop->suspend
262
263=item EV::resume
264
265=item $loop->resume
266
267These two functions suspend and resume a loop, for use when the loop is
268not used for a while and timeouts should not be processed.
269
270A typical use case would be an interactive program such as a game: When
271the user presses C<^Z> to suspend the game and resumes it an hour later it
272would be best to handle timeouts as if no time had actually passed while
273the program was suspended. This can be achieved by calling C<suspend>
274in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
275C<resume> directly afterwards to resume timer processing.
276
277Effectively, all C<timer> watchers will be delayed by the time spend
278between C<suspend> and C<resume>, and all C<periodic> watchers
279will be rescheduled (that is, they will lose any events that would have
280occured while suspended).
281
282After calling C<suspend> you B<must not> call I<any> function on the given
283loop other than C<resume>, and you B<must not> call C<resume>
284without a previous call to C<suspend>.
285
286Calling C<suspend>/C<resume> has the side effect of updating the event
287loop time (see C<now_update>).
288
176=item $backend = EV::backend 289=item $backend = EV::backend
177 290
178=item $backend = $loop->backend 291=item $backend = $loop->backend
179 292
180Returns an integer describing the backend used by libev (EV::METHOD_SELECT 293Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
181or EV::METHOD_EPOLL). 294or EV::BACKEND_EPOLL).
182 295
183=item EV::loop [$flags] 296=item $active = EV::run [$flags]
184 297
185=item $loop->loop ([$flags]) 298=item $active = $loop->run ([$flags])
186 299
187Begin checking for events and calling callbacks. It returns when a 300Begin checking for events and calling callbacks. It returns when a
188callback calls EV::unloop. 301callback calls EV::unloop or the flasg are nonzero (in which case the
302return value is true) or when there are no active watchers which reference
303the loop (keepalive is true), in which case the return value will be
304false. The returnv alue can generally be interpreted as "if true, there is
305more work left to do".
189 306
190The $flags argument can be one of the following: 307The $flags argument can be one of the following:
191 308
192 0 as above 309 0 as above
193 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 310 EV::RUN_ONCE block at most once (wait, but do not loop)
194 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 311 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
195 312
196=item EV::unloop [$how] 313=item EV::break [$how]
197 314
198=item $loop->unloop ([$how]) 315=item $loop->break ([$how])
199 316
200When called with no arguments or an argument of EV::UNLOOP_ONE, makes the 317When called with no arguments or an argument of EV::BREAK_ONE, makes the
201innermost call to EV::loop return. 318innermost call to EV::loop return.
202 319
203When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as 320When called with an argument of EV::BREAK_ALL, all calls to EV::loop will
204fast as possible. 321return as fast as possible.
205 322
206=item $count = EV::loop_count 323When called with an argument of EV::BREAK_CANCEL, any pending break will
324be cancelled.
207 325
326=item $count = EV::iteration
327
208=item $count = $loop->loop_count 328=item $count = $loop->iteration
209 329
210Return the number of times the event loop has polled for new 330Return the number of times the event loop has polled for new
211events. Sometiems useful as a generation counter. 331events. Sometimes useful as a generation counter.
212 332
213=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 333=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
214 334
215=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 335=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
216 336
… …
227timeout. Otherwise a EV::timer with this value will be started. 347timeout. Otherwise a EV::timer with this value will be started.
228 348
229When an error occurs or either the timeout or I/O watcher triggers, then 349When an error occurs or either the timeout or I/O watcher triggers, then
230the callback will be called with the received event set (in general 350the callback will be called with the received event set (in general
231you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>, 351you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
232C<EV::WRITE> and C<EV::TIMEOUT>). 352C<EV::WRITE> and C<EV::TIMER>).
233 353
234EV::once doesn't return anything: the watchers stay active till either 354EV::once doesn't return anything: the watchers stay active till either
235of them triggers, then they will be stopped and freed, and the callback 355of them triggers, then they will be stopped and freed, and the callback
236invoked. 356invoked.
237 357
238=item EV::feed_fd_event ($fd, $revents) 358=item EV::feed_fd_event $fd, $revents
239 359
240=item $loop->feed_fd_event ($fd, $revents) 360=item $loop->feed_fd_event ($fd, $revents)
241 361
242Feed an event on a file descriptor into EV. EV will react to this call as 362Feed an event on a file descriptor into EV. EV will react to this call as
243if the readyness notifications specified by C<$revents> (a combination of 363if the readyness notifications specified by C<$revents> (a combination of
244C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. 364C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
245 365
246=item EV::feed_signal_event ($signal) 366=item EV::feed_signal_event $signal
247 367
248Feed a signal event into EV. EV will react to this call as if the signal 368Feed a signal event into the default loop. EV will react to this call as
249specified by C<$signal> had occured. 369if the signal specified by C<$signal> had occured.
370
371=item EV::feed_signal $signal
372
373Feed a signal event into EV - unlike C<EV::feed_signal_event>, this works
374regardless of which loop has registered the signal, and is mainly useful
375fro custom signal implementations.
250 376
251=item EV::set_io_collect_interval $time 377=item EV::set_io_collect_interval $time
252 378
253=item $loop->set_io_collect_interval ($time) 379=item $loop->set_io_collect_interval ($time)
254 380
… …
256 382
257=item $loop->set_timeout_collect_interval ($time) 383=item $loop->set_timeout_collect_interval ($time)
258 384
259These advanced functions set the minimum block interval when polling for I/O events and the minimum 385These advanced functions set the minimum block interval when polling for I/O events and the minimum
260wait interval for timer events. See the libev documentation at 386wait interval for timer events. See the libev documentation at
261L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> for 387L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
262a more detailed discussion. 388(locally installed as F<EV::libev>) for a more detailed discussion.
389
390=item $count = EV::pending_count
391
392=item $count = $loop->pending_count
393
394Returns the number of currently pending watchers.
395
396=item EV::invoke_pending
397
398=item $loop->invoke_pending
399
400Invoke all currently pending watchers.
263 401
264=back 402=back
265 403
266 404
267=head1 WATCHER OBJECTS 405=head1 WATCHER OBJECTS
268 406
269A watcher is an object that gets created to record your interest in some 407A watcher is an object that gets created to record your interest in some
270event. For instance, if you want to wait for STDIN to become readable, you 408event. For instance, if you want to wait for STDIN to become readable, you
271would create an EV::io watcher for that: 409would create an EV::io watcher for that:
272 410
273 my $watcher = EV::io *STDIN, EV::READ, sub { 411 my $watcher = EV::io *STDIN, EV::READ, sub {
274 my ($watcher, $revents) = @_; 412 my ($watcher, $revents) = @_;
275 warn "yeah, STDIN should now be readable without blocking!\n" 413 warn "yeah, STDIN should now be readable without blocking!\n"
276 }; 414 };
277 415
278All watchers can be active (waiting for events) or inactive (paused). Only 416All watchers can be active (waiting for events) or inactive (paused). Only
279active watchers will have their callbacks invoked. All callbacks will be 417active watchers will have their callbacks invoked. All callbacks will be
280called with at least two arguments: the watcher and a bitmask of received 418called with at least two arguments: the watcher and a bitmask of received
281events. 419events.
282 420
283Each watcher type has its associated bit in revents, so you can use the 421Each watcher type has its associated bit in revents, so you can use the
284same callback for multiple watchers. The event mask is named after the 422same callback for multiple watchers. The event mask is named after the
285type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 423type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
286EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events 424EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
287(which can set both EV::READ and EV::WRITE bits), and EV::timer (which 425(which can set both EV::READ and EV::WRITE bits).
288uses EV::TIMEOUT).
289 426
290In the rare case where one wants to create a watcher but not start it at 427In the rare case where one wants to create a watcher but not start it at
291the same time, each constructor has a variant with a trailing C<_ns> in 428the same time, each constructor has a variant with a trailing C<_ns> in
292its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. 429its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
293 430
… …
372 509
373=item $previous_state = $w->keepalive ($bool) 510=item $previous_state = $w->keepalive ($bool)
374 511
375Normally, C<EV::loop> will return when there are no active watchers 512Normally, C<EV::loop> will return when there are no active watchers
376(which is a "deadlock" because no progress can be made anymore). This is 513(which is a "deadlock" because no progress can be made anymore). This is
377convinient because it allows you to start your watchers (and your jobs), 514convenient because it allows you to start your watchers (and your jobs),
378call C<EV::loop> once and when it returns you know that all your jobs are 515call C<EV::loop> once and when it returns you know that all your jobs are
379finished (or they forgot to register some watchers for their task :). 516finished (or they forgot to register some watchers for their task :).
380 517
381Sometimes, however, this gets in your way, for example when the module 518Sometimes, however, this gets in your way, for example when the module
382that calls C<EV::loop> (usually the main program) is not the same module 519that calls C<EV::loop> (usually the main program) is not the same module
… …
386because you happen to have this long-running UDP port watcher. 523because you happen to have this long-running UDP port watcher.
387 524
388In this case you can clear the keepalive status, which means that even 525In this case you can clear the keepalive status, which means that even
389though your watcher is active, it won't keep C<EV::loop> from returning. 526though your watcher is active, it won't keep C<EV::loop> from returning.
390 527
391The initial value for keepalive is true (enabled), and you cna change it 528The initial value for keepalive is true (enabled), and you can change it
392any time. 529any time.
393 530
394Example: Register an I/O watcher for some UDP socket but do not keep the 531Example: Register an I/O watcher for some UDP socket but do not keep the
395event loop from running just because of that watcher. 532event loop from running just because of that watcher.
396 533
397 my $udp_socket = ... 534 my $udp_socket = ...
398 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 535 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
399 $1000udp_watcher->keepalive (0); 536 $udp_watcher->keepalive (0);
400 537
401=item $loop = $w->loop 538=item $loop = $w->loop
402 539
403Return the loop that this watcher is attached to. 540Return the loop that this watcher is attached to.
404 541
… …
533This time simply fires at the wallclock time C<$at> and doesn't repeat. It 670This time simply fires at the wallclock time C<$at> and doesn't repeat. It
534will not adjust when a time jump occurs, that is, if it is to be run 671will not adjust when a time jump occurs, that is, if it is to be run
535at January 1st 2011 then it will run when the system time reaches or 672at January 1st 2011 then it will run when the system time reaches or
536surpasses this time. 673surpasses this time.
537 674
538=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 675=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
539 676
540In this mode the watcher will always be scheduled to time out at the 677In this mode the watcher will always be scheduled to time out at the
541next C<$at + N * $interval> time (for some integer N) and then repeat, 678next C<$at + N * $interval> time (for some integer N) and then repeat,
542regardless of any time jumps. 679regardless of any time jumps.
543 680
… …
545time: 682time:
546 683
547 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; 684 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
548 685
549That doesn't mean there will always be 3600 seconds in between triggers, 686That doesn't mean there will always be 3600 seconds in between triggers,
550but only that the the clalback will be called when the system time shows a 687but only that the the callback will be called when the system time shows a
551full hour (UTC). 688full hour (UTC).
552 689
553Another way to think about it (for the mathematically inclined) is that 690Another way to think about it (for the mathematically inclined) is that
554EV::periodic will try to run the callback in this mode at the next 691EV::periodic will try to run the callback in this mode at the next
555possible time where C<$time = $at (mod $interval)>, regardless of any time 692possible time where C<$time = $at (mod $interval)>, regardless of any time
… …
561time the periodic watcher gets scheduled, the reschedule callback 698time the periodic watcher gets scheduled, the reschedule callback
562($reschedule_cb) will be called with the watcher as first, and the current 699($reschedule_cb) will be called with the watcher as first, and the current
563time as second argument. 700time as second argument.
564 701
565I<This callback MUST NOT stop or destroy this or any other periodic 702I<This callback MUST NOT stop or destroy this or any other periodic
566watcher, ever>. If you need to stop it, return 1e30 and stop it 703watcher, ever, and MUST NOT call any event loop functions or methods>. If
567afterwards. 704you need to stop it, return 1e30 and stop it afterwards. You may create
705and start a C<EV::prepare> watcher for this task.
568 706
569It must return the next time to trigger, based on the passed time value 707It must return the next time to trigger, based on the passed time value
570(that is, the lowest time value larger than to the second argument). It 708(that is, the lowest time value larger than or equal to to the second
571will usually be called just before the callback will be triggered, but 709argument). It will usually be called just before the callback will be
572might be called at other times, too. 710triggered, but might be called at other times, too.
573 711
574This can be used to create very complex timers, such as a timer that 712This can be used to create very complex timers, such as a timer that
575triggers on each midnight, local time (actually 24 hours after the last 713triggers on each midnight, local time (actually 24 hours after the last
576midnight, to keep the example simple. If you know a way to do it correctly 714midnight, to keep the example simple. If you know a way to do it correctly
577in about the same space (without requiring elaborate modules), drop me a 715in about the same space (without requiring elaborate modules), drop me a
… …
613 751
614=item $w = EV::signal $signal, $callback 752=item $w = EV::signal $signal, $callback
615 753
616=item $w = EV::signal_ns $signal, $callback 754=item $w = EV::signal_ns $signal, $callback
617 755
756=item $w = $loop->signal ($signal, $callback)
757
758=item $w = $loop->signal_ns ($signal, $callback)
759
618Call the callback when $signal is received (the signal can be specified by 760Call the callback when $signal is received (the signal can be specified by
619number or by name, just as with C<kill> or C<%SIG>). 761number or by name, just as with C<kill> or C<%SIG>).
762
763Only one event loop can grab a given signal - attempting to grab the same
764signal from two EV loops will crash the program immediately or cause data
765corruption.
620 766
621EV will grab the signal for the process (the kernel only allows one 767EV will grab the signal for the process (the kernel only allows one
622component to receive a signal at a time) when you start a signal watcher, 768component to receive a signal at a time) when you start a signal watcher,
623and removes it again when you stop it. Perl does the same when you 769and removes it again when you stop it. Perl does the same when you
624add/remove callbacks to C<%SIG>, so watch out. 770add/remove callbacks to C<%SIG>, so watch out.
… …
849=item $w = $loop->check_ns ($callback) 995=item $w = $loop->check_ns ($callback)
850 996
851Call the callback just after the process wakes up again (after it has 997Call the callback just after the process wakes up again (after it has
852gathered events), but before any other callbacks have been invoked. 998gathered events), but before any other callbacks have been invoked.
853 999
854This is used to integrate other event-based software into the EV 1000This can be used to integrate other event-based software into the EV
855mainloop: You register a prepare callback and in there, you create io and 1001mainloop: You register a prepare callback and in there, you create io and
856timer watchers as required by the other software. Here is a real-world 1002timer watchers as required by the other software. Here is a real-world
857example of integrating Net::SNMP (with some details left out): 1003example of integrating Net::SNMP (with some details left out):
858 1004
859 our @snmp_watcher; 1005 our @snmp_watcher;
… …
889 # make the dispatcher handle any new stuff 1035 # make the dispatcher handle any new stuff
890 ... not shown 1036 ... not shown
891 }; 1037 };
892 1038
893The callbacks of the created watchers will not be called as the watchers 1039The callbacks of the created watchers will not be called as the watchers
894are destroyed before this cna happen (remember EV::check gets called 1040are destroyed before this can happen (remember EV::check gets called
895first). 1041first).
896 1042
897The C<check_ns> variant doesn't start (activate) the newly created watcher. 1043The C<check_ns> variant doesn't start (activate) the newly created watcher.
1044
1045=item EV::CHECK constant issues
1046
1047Like all other watcher types, there is a bitmask constant for use in
1048C<$revents> and other places. The C<EV::CHECK> is special as it has
1049the same name as the C<CHECK> sub called by Perl. This doesn't cause
1050big issues on newer perls (beginning with 5.8.9), but it means thatthe
1051constant must be I<inlined>, i.e. runtime calls will not work. That means
1052that as long as you always C<use EV> and then C<EV::CHECK> you are on the
1053safe side.
898 1054
899=back 1055=back
900 1056
901 1057
902=head3 FORK WATCHERS - the audacity to resume the event loop after a fork 1058=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
… …
930loop, other types of watchers might be handled in a delayed or incorrect 1086loop, other types of watchers might be handled in a delayed or incorrect
931fashion and must not be used). 1087fashion and must not be used).
932 1088
933See the libev documentation at 1089See the libev documentation at
934L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> 1090L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
935for more details. 1091(locally installed as F<EV::libev>) for more details.
936 1092
937In short, this watcher is most useful on BSD systems without working 1093In short, this watcher is most useful on BSD systems without working
938kqueue to still be able to handle a large number of sockets: 1094kqueue to still be able to handle a large number of sockets:
939 1095
940 my $socket_loop; 1096 my $socket_loop;
941 1097
942 # check wether we use SELECT or POLL _and_ KQUEUE is supported 1098 # check wether we use SELECT or POLL _and_ KQUEUE is supported
943 if ( 1099 if (
944 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 1100 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
945 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 1101 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
946 ) { 1102 ) {
947 # use kqueue for sockets 1103 # use kqueue for sockets
948 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 1104 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
949 } 1105 }
950 1106
951 # use the default loop otherwise 1107 # use the default loop otherwise
952 $socket_loop ||= EV::default_loop; 1108 $socket_loop ||= EV::default_loop;
953 1109
954=over 4 1110=over 4
955 1111
956=item $w = EV::embed $otherloop, $callback 1112=item $w = EV::embed $otherloop[, $callback]
957 1113
958=item $w = EV::embed_ns $otherloop, $callback 1114=item $w = EV::embed_ns $otherloop[, $callback]
959 1115
960=item $w = $loop->embed ($otherloop, $callback) 1116=item $w = $loop->embed ($otherloop[, $callback])
961 1117
962=item $w = $loop->embed_ns ($otherloop, $callback) 1118=item $w = $loop->embed_ns ($otherloop[, $callback])
963 1119
964Call the callback when the embedded event loop (C<$otherloop>) has any 1120Call the callback when the embedded event loop (C<$otherloop>) has any
965I/O activity. The C<$callback> should alwas be specified as C<undef> in 1121I/O activity. The C<$callback> is optional: if it is missing, then the
966this version of EV, which means the embedded event loop will be managed 1122embedded event loop will be managed automatically (which is recommended),
967automatically. 1123otherwise you have to invoke C<sweep> yourself.
968 1124
969The C<embed_ns> variant doesn't start (activate) the newly created watcher. 1125The C<embed_ns> variant doesn't start (activate) the newly created watcher.
970 1126
971=back 1127=back
1128
1129=head3 ASYNC WATCHERS - how to wake up another event loop
1130
1131Async watchers are provided by EV, but have little use in perl directly,
1132as perl neither supports threads running in parallel nor direct access to
1133signal handlers or other contexts where they could be of value.
1134
1135It is, however, possible to use them from the XS level.
1136
1137Please see the libev documentation for further details.
1138
1139=over 4
1140
1141=item $w = EV::async $callback
1142
1143=item $w = EV::async_ns $callback
1144
1145=item $w = $loop->async ($callback)
1146
1147=item $w = $loop->async_ns ($callback)
1148
1149=item $w->send
1150
1151=item $bool = $w->async_pending
1152
1153=back
1154
1155=head3 CLEANUP WATCHERS - how to clean up when the event loop goes away
1156
1157Cleanup watchers are not supported on the Perl level, they can only be
1158used via XS currently.
972 1159
973 1160
974=head1 PERL SIGNALS 1161=head1 PERL SIGNALS
975 1162
976While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour 1163While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
… …
988 my $async_check = EV::check sub { }; 1175 my $async_check = EV::check sub { };
989 1176
990This ensures that perl gets into control for a short time to handle any 1177This ensures that perl gets into control for a short time to handle any
991pending signals, and also ensures (slightly) slower overall operation. 1178pending signals, and also ensures (slightly) slower overall operation.
992 1179
993=head1 THREADS 1180=head1 ITHREADS
994 1181
995Threads are not supported by this module in any way. Perl pseudo-threads 1182Ithreads are not supported by this module in any way. Perl pseudo-threads
996is evil stuff and must die. As soon as Perl gains real threads I will work 1183is evil stuff and must die. Real threads as provided by Coro are fully
997on thread support for it. 1184supported (and enhanced support is available via L<Coro::EV>).
998 1185
999=head1 FORK 1186=head1 FORK
1000 1187
1001Most of the "improved" event delivering mechanisms of modern operating 1188Most of the "improved" event delivering mechanisms of modern operating
1002systems have quite a few problems with fork(2) (to put it bluntly: it is 1189systems have quite a few problems with fork(2) (to put it bluntly: it is
… …
1024 1211
10251; 12121;
1026 1213
1027=head1 SEE ALSO 1214=head1 SEE ALSO
1028 1215
1216L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS>
1029L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as 1217(asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as event
1030event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient 1218loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient thread
1031coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP). 1219integration), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1220event-loop agnostic and portable event driven programming.
1032 1221
1033=head1 AUTHOR 1222=head1 AUTHOR
1034 1223
1035 Marc Lehmann <schmorp@schmorp.de> 1224 Marc Lehmann <schmorp@schmorp.de>
1036 http://home.schmorp.de/ 1225 http://home.schmorp.de/
1037 1226
1038=cut 1227=cut
1039 1228

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