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Revision 1.86 by root, Wed Apr 2 11:00:58 2008 UTC vs.
Revision 1.152 by root, Sun Oct 28 23:40:32 2018 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::break 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 = '3.2'; 124 our $VERSION = 4.22;
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 =
… …
105default loop as this is fastest (perl-wise), best supported by other 157default loop as this is fastest (perl-wise), best supported by other
106modules (e.g. AnyEvent or Coro) and most portable event loop. 158modules (e.g. AnyEvent or Coro) and most portable event loop.
107 159
108For specific programs you can create additional event loops dynamically. 160For specific programs you can create additional event loops dynamically.
109 161
110=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.
111 167
168=over 4
169
112=item $loop = new EV::loop [$flags] 170=item $loop = new EV::Loop [$flags]
113 171
114Create 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
115C<ev_loop_new ()> function description in the libev documentation 173the C<ev_loop_new ()> function description in the libev documentation
116(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>,
117for more info. 175or locally-installed as F<EV::libev> manpage) for more info.
118 176
119The loop will automatically be destroyed when it is no longer referenced 177The loop will automatically be destroyed when it is no longer referenced
120by any watcher and the loop object goes out of scope. 178by any watcher and the loop object goes out of scope.
121 179
122Using 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>
123is 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.
124 184
125=item $loop->loop_fork 185=item $loop->loop_fork
126 186
127Must 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
128the 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
129this fucntion automatically, at some performance loss (refer to the libev 189this function automatically, at some performance loss (refer to the libev
130documentation). 190documentation).
131 191
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
132=item $loop = EV::default_loop [$flags] 198=item $loop = EV::default_loop [$flags]
133 199
134Return 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.
135 205
136=back 206=back
137 207
138 208
139=head1 BASIC INTERFACE 209=head1 BASIC INTERFACE
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169=item $time = EV::now 239=item $time = EV::now
170 240
171=item $time = $loop->now 241=item $time = $loop->now
172 242
173Returns the time the last event loop iteration has been started. This 243Returns the time the last event loop iteration has been started. This
174is 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
175usually faster then calling EV::time. 245usually faster then calling EV::time.
176 246
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
177=item $backend = EV::backend 289=item $backend = EV::backend
178 290
179=item $backend = $loop->backend 291=item $backend = $loop->backend
180 292
181Returns an integer describing the backend used by libev (EV::METHOD_SELECT 293Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
182or EV::METHOD_EPOLL). 294or EV::BACKEND_EPOLL).
183 295
184=item EV::loop [$flags] 296=item $active = EV::run [$flags]
185 297
186=item $loop->loop ([$flags]) 298=item $active = $loop->run ([$flags])
187 299
188Begin checking for events and calling callbacks. It returns when a 300Begin checking for events and calling callbacks. It returns when a
189callback calls EV::unloop. 301callback calls EV::break or the flags 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 return value can generally be interpreted as "if true, there is
305more work left to do".
190 306
191The $flags argument can be one of the following: 307The $flags argument can be one of the following:
192 308
193 0 as above 309 0 as above
194 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 310 EV::RUN_ONCE block at most once (wait, but do not loop)
195 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 311 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
196 312
197=item EV::unloop [$how] 313=item EV::break [$how]
198 314
199=item $loop->unloop ([$how]) 315=item $loop->break ([$how])
200 316
201When 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
202innermost call to EV::loop return. 318innermost call to EV::loop return.
203 319
204When 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
205fast as possible. 321return as fast as possible.
206 322
207=item $count = EV::loop_count 323When called with an argument of EV::BREAK_CANCEL, any pending break will
324be cancelled.
208 325
326=item $count = EV::iteration
327
209=item $count = $loop->loop_count 328=item $count = $loop->iteration
210 329
211Return the number of times the event loop has polled for new 330Return the number of times the event loop has polled for new
212events. Sometiems useful as a generation counter. 331events. Sometimes useful as a generation counter.
213 332
214=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 333=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
215 334
216=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 335=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
217 336
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228timeout. Otherwise a EV::timer with this value will be started. 347timeout. Otherwise a EV::timer with this value will be started.
229 348
230When 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
231the callback will be called with the received event set (in general 350the callback will be called with the received event set (in general
232you 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>,
233C<EV::WRITE> and C<EV::TIMEOUT>). 352C<EV::WRITE> and C<EV::TIMER>).
234 353
235EV::once doesn't return anything: the watchers stay active till either 354EV::once doesn't return anything: the watchers stay active till either
236of 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
237invoked. 356invoked.
238 357
239=item EV::feed_fd_event ($fd, $revents) 358=item EV::feed_fd_event $fd, $revents
240 359
241=item $loop->feed_fd_event ($fd, $revents) 360=item $loop->feed_fd_event ($fd, $revents)
242 361
243Feed an event on a file descriptor into EV. EV will react to this call as 362Feed an event on a file descriptor into EV. EV will react to this call as
244if the readyness notifications specified by C<$revents> (a combination of 363if the readyness notifications specified by C<$revents> (a combination of
245C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. 364C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
246 365
247=item EV::feed_signal_event ($signal) 366=item EV::feed_signal_event $signal
248 367
249Feed a signal event into EV. EV will react to this call as if the signal 368Feed a signal event into the default loop. EV will react to this call as
250specified by C<$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.
251 376
252=item EV::set_io_collect_interval $time 377=item EV::set_io_collect_interval $time
253 378
254=item $loop->set_io_collect_interval ($time) 379=item $loop->set_io_collect_interval ($time)
255 380
… …
257 382
258=item $loop->set_timeout_collect_interval ($time) 383=item $loop->set_timeout_collect_interval ($time)
259 384
260These 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
261wait interval for timer events. See the libev documentation at 386wait interval for timer events. See the libev documentation at
262L<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>
263a 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.
264 401
265=back 402=back
266 403
267 404
268=head1 WATCHER OBJECTS 405=head1 WATCHER OBJECTS
269 406
270A 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
271event. 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
272would create an EV::io watcher for that: 409would create an EV::io watcher for that:
273 410
274 my $watcher = EV::io *STDIN, EV::READ, sub { 411 my $watcher = EV::io *STDIN, EV::READ, sub {
275 my ($watcher, $revents) = @_; 412 my ($watcher, $revents) = @_;
276 warn "yeah, STDIN should now be readable without blocking!\n" 413 warn "yeah, STDIN should now be readable without blocking!\n"
277 }; 414 };
278 415
279All watchers can be active (waiting for events) or inactive (paused). Only 416All watchers can be active (waiting for events) or inactive (paused). Only
280active watchers will have their callbacks invoked. All callbacks will be 417active watchers will have their callbacks invoked. All callbacks will be
281called 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
282events. 419events.
283 420
284Each 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
285same callback for multiple watchers. The event mask is named after the 422same callback for multiple watchers. The event mask is named after the
286type, 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,
287EV::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
288(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).
289uses EV::TIMEOUT).
290 426
291In 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
292the 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
293its 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.
294 430
… …
373 509
374=item $previous_state = $w->keepalive ($bool) 510=item $previous_state = $w->keepalive ($bool)
375 511
376Normally, C<EV::loop> will return when there are no active watchers 512Normally, C<EV::loop> will return when there are no active watchers
377(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
378convinient because it allows you to start your watchers (and your jobs), 514convenient because it allows you to start your watchers (and your jobs),
379call 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
380finished (or they forgot to register some watchers for their task :). 516finished (or they forgot to register some watchers for their task :).
381 517
382Sometimes, however, this gets in your way, for example when the module 518Sometimes, however, this gets in your way, for example when the module
383that 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
… …
387because you happen to have this long-running UDP port watcher. 523because you happen to have this long-running UDP port watcher.
388 524
389In 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
390though 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.
391 527
392The 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
393any time. 529any time.
394 530
395Example: 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
396event loop from running just because of that watcher. 532event loop from running just because of that watcher.
397 533
398 my $udp_socket = ... 534 my $udp_socket = ...
399 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 535 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
400 $1000udp_watcher->keepalive (0); 536 $udp_watcher->keepalive (0);
401 537
402=item $loop = $w->loop 538=item $loop = $w->loop
403 539
404Return the loop that this watcher is attached to. 540Return the loop that this watcher is attached to.
405 541
… …
462 598
463=item $w = $loop->timer ($after, $repeat, $callback) 599=item $w = $loop->timer ($after, $repeat, $callback)
464 600
465=item $w = $loop->timer_ns ($after, $repeat, $callback) 601=item $w = $loop->timer_ns ($after, $repeat, $callback)
466 602
467Calls the callback after C<$after> seconds (which may be fractional). If 603Calls the callback after C<$after> seconds (which may be fractional or
468C<$repeat> is non-zero, the timer will be restarted (with the $repeat 604negative). If C<$repeat> is non-zero, the timer will be restarted (with
469value as $after) after the callback returns. 605the $repeat value as $after) after the callback returns.
470 606
471This means that the callback would be called roughly after C<$after> 607This means that the callback would be called roughly after C<$after>
472seconds, and then every C<$repeat> seconds. The timer does his best not 608seconds, and then every C<$repeat> seconds. The timer does his best not
473to drift, but it will not invoke the timer more often then once per event 609to drift, but it will not invoke the timer more often then once per event
474loop iteration, and might drift in other cases. If that isn't acceptable, 610loop iteration, and might drift in other cases. If that isn't acceptable,
… …
478in front of the machine while the timer is running and changes the system 614in front of the machine while the timer is running and changes the system
479clock, the timer will nevertheless run (roughly) the same time. 615clock, the timer will nevertheless run (roughly) the same time.
480 616
481The C<timer_ns> variant doesn't start (activate) the newly created watcher. 617The C<timer_ns> variant doesn't start (activate) the newly created watcher.
482 618
483=item $w->set ($after, $repeat) 619=item $w->set ($after, $repeat = 0)
484 620
485Reconfigures the watcher, see the constructor above for details. Can be called at 621Reconfigures the watcher, see the constructor above for details. Can be called at
486any time. 622any time.
487 623
488=item $w->again 624=item $w->again
625
626=item $w->again ($repeat)
489 627
490Similar to the C<start> method, but has special semantics for repeating timers: 628Similar to the C<start> method, but has special semantics for repeating timers:
491 629
492If the timer is active and non-repeating, it will be stopped. 630If the timer is active and non-repeating, it will be stopped.
493 631
… …
500 638
501This behaviour is useful when you have a timeout for some IO 639This behaviour is useful when you have a timeout for some IO
502operation. You create a timer object with the same value for C<$after> and 640operation. You create a timer object with the same value for C<$after> and
503C<$repeat>, and then, in the read/write watcher, run the C<again> method 641C<$repeat>, and then, in the read/write watcher, run the C<again> method
504on the timeout. 642on the timeout.
643
644If called with a C<$repeat> argument, then it uses this a timer repeat
645value.
646
647=item $after = $w->remaining
648
649Calculates and returns the remaining time till the timer will fire.
505 650
506=back 651=back
507 652
508 653
509=head3 PERIODIC WATCHERS - to cron or not to cron? 654=head3 PERIODIC WATCHERS - to cron or not to cron?
… …
537surpasses this time. 682surpasses this time.
538 683
539=item * repeating interval timer ($interval > 0, $reschedule_cb = 0) 684=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
540 685
541In this mode the watcher will always be scheduled to time out at the 686In this mode the watcher will always be scheduled to time out at the
542next C<$at + N * $interval> time (for some integer N) and then repeat, 687next C<$at + N * $interval> time (for the lowest integer N) and then repeat,
543regardless of any time jumps. 688regardless of any time jumps. Note that, since C<N> can be negative, the
689first trigger can happen before C<$at>.
544 690
545This can be used to create timers that do not drift with respect to system 691This can be used to create timers that do not drift with respect to system
546time: 692time:
547 693
548 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; 694 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
549 695
550That doesn't mean there will always be 3600 seconds in between triggers, 696That doesn't mean there will always be 3600 seconds in between triggers,
551but only that the the clalback will be called when the system time shows a 697but only that the the callback will be called when the system time shows a
552full hour (UTC). 698full hour (UTC).
553 699
554Another way to think about it (for the mathematically inclined) is that 700Another way to think about it (for the mathematically inclined) is that
555EV::periodic will try to run the callback in this mode at the next 701EV::periodic will try to run the callback in this mode at the next
556possible time where C<$time = $at (mod $interval)>, regardless of any time 702possible time where C<$time = $at (mod $interval)>, regardless of any time
… …
562time the periodic watcher gets scheduled, the reschedule callback 708time the periodic watcher gets scheduled, the reschedule callback
563($reschedule_cb) will be called with the watcher as first, and the current 709($reschedule_cb) will be called with the watcher as first, and the current
564time as second argument. 710time as second argument.
565 711
566I<This callback MUST NOT stop or destroy this or any other periodic 712I<This callback MUST NOT stop or destroy this or any other periodic
567watcher, ever>. If you need to stop it, return 1e30 and stop it 713watcher, ever, and MUST NOT call any event loop functions or methods>. If
568afterwards. 714you need to stop it, return 1e30 and stop it afterwards. You may create
715and start a C<EV::prepare> watcher for this task.
569 716
570It must return the next time to trigger, based on the passed time value 717It must return the next time to trigger, based on the passed time value
571(that is, the lowest time value larger than to the second argument). It 718(that is, the lowest time value larger than or equal to to the second
572will usually be called just before the callback will be triggered, but 719argument). It will usually be called just before the callback will be
573might be called at other times, too. 720triggered, but might be called at other times, too.
574 721
575This can be used to create very complex timers, such as a timer that 722This can be used to create very complex timers, such as a timer that
576triggers on each midnight, local time (actually 24 hours after the last 723triggers on each midnight, local time (actually one day after the last
577midnight, to keep the example simple. If you know a way to do it correctly 724midnight, to keep the example simple):
578in about the same space (without requiring elaborate modules), drop me a
579note :):
580 725
581 my $daily = EV::periodic 0, 0, sub { 726 my $daily = EV::periodic 0, 0, sub {
582 my ($w, $now) = @_; 727 my ($w, $now) = @_;
583 728
584 use Time::Local (); 729 use Time::Local ();
585 my (undef, undef, undef, $d, $m, $y) = localtime $now; 730 my (undef, undef, undef, $d, $m, $y) = localtime $now;
586 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y 731 Time::Local::timelocal_nocheck 0, 0, 0, $d + 1, $m, $y
587 }, sub { 732 }, sub {
588 print "it's midnight or likely shortly after, now\n"; 733 print "it's midnight or likely shortly after, now\n";
589 }; 734 };
590 735
591=back 736=back
… …
614 759
615=item $w = EV::signal $signal, $callback 760=item $w = EV::signal $signal, $callback
616 761
617=item $w = EV::signal_ns $signal, $callback 762=item $w = EV::signal_ns $signal, $callback
618 763
764=item $w = $loop->signal ($signal, $callback)
765
766=item $w = $loop->signal_ns ($signal, $callback)
767
619Call the callback when $signal is received (the signal can be specified by 768Call the callback when $signal is received (the signal can be specified by
620number or by name, just as with C<kill> or C<%SIG>). 769number or by name, just as with C<kill> or C<%SIG>).
770
771Only one event loop can grab a given signal - attempting to grab the same
772signal from two EV loops will crash the program immediately or cause data
773corruption.
621 774
622EV will grab the signal for the process (the kernel only allows one 775EV will grab the signal for the process (the kernel only allows one
623component to receive a signal at a time) when you start a signal watcher, 776component to receive a signal at a time) when you start a signal watcher,
624and removes it again when you stop it. Perl does the same when you 777and removes it again when you stop it. Perl does the same when you
625add/remove callbacks to C<%SIG>, so watch out. 778add/remove callbacks to C<%SIG>, so watch out.
… …
850=item $w = $loop->check_ns ($callback) 1003=item $w = $loop->check_ns ($callback)
851 1004
852Call the callback just after the process wakes up again (after it has 1005Call the callback just after the process wakes up again (after it has
853gathered events), but before any other callbacks have been invoked. 1006gathered events), but before any other callbacks have been invoked.
854 1007
855This is used to integrate other event-based software into the EV 1008This can be used to integrate other event-based software into the EV
856mainloop: You register a prepare callback and in there, you create io and 1009mainloop: You register a prepare callback and in there, you create io and
857timer watchers as required by the other software. Here is a real-world 1010timer watchers as required by the other software. Here is a real-world
858example of integrating Net::SNMP (with some details left out): 1011example of integrating Net::SNMP (with some details left out):
859 1012
860 our @snmp_watcher; 1013 our @snmp_watcher;
… …
890 # make the dispatcher handle any new stuff 1043 # make the dispatcher handle any new stuff
891 ... not shown 1044 ... not shown
892 }; 1045 };
893 1046
894The callbacks of the created watchers will not be called as the watchers 1047The callbacks of the created watchers will not be called as the watchers
895are destroyed before this cna happen (remember EV::check gets called 1048are destroyed before this can happen (remember EV::check gets called
896first). 1049first).
897 1050
898The C<check_ns> variant doesn't start (activate) the newly created watcher. 1051The C<check_ns> variant doesn't start (activate) the newly created watcher.
1052
1053=item EV::CHECK constant issues
1054
1055Like all other watcher types, there is a bitmask constant for use in
1056C<$revents> and other places. The C<EV::CHECK> is special as it has
1057the same name as the C<CHECK> sub called by Perl. This doesn't cause
1058big issues on newer perls (beginning with 5.8.9), but it means thatthe
1059constant must be I<inlined>, i.e. runtime calls will not work. That means
1060that as long as you always C<use EV> and then C<EV::CHECK> you are on the
1061safe side.
899 1062
900=back 1063=back
901 1064
902 1065
903=head3 FORK WATCHERS - the audacity to resume the event loop after a fork 1066=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
… …
931loop, other types of watchers might be handled in a delayed or incorrect 1094loop, other types of watchers might be handled in a delayed or incorrect
932fashion and must not be used). 1095fashion and must not be used).
933 1096
934See the libev documentation at 1097See the libev documentation at
935L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> 1098L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
936for more details. 1099(locally installed as F<EV::libev>) for more details.
937 1100
938In short, this watcher is most useful on BSD systems without working 1101In short, this watcher is most useful on BSD systems without working
939kqueue to still be able to handle a large number of sockets: 1102kqueue to still be able to handle a large number of sockets:
940 1103
941 my $socket_loop; 1104 my $socket_loop;
942 1105
943 # check wether we use SELECT or POLL _and_ KQUEUE is supported 1106 # check wether we use SELECT or POLL _and_ KQUEUE is supported
944 if ( 1107 if (
945 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 1108 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
946 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 1109 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
947 ) { 1110 ) {
948 # use kqueue for sockets 1111 # use kqueue for sockets
949 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 1112 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
950 } 1113 }
951 1114
952 # use the default loop otherwise 1115 # use the default loop otherwise
953 $socket_loop ||= EV::default_loop; 1116 $socket_loop ||= EV::default_loop;
954 1117
955=over 4 1118=over 4
956 1119
957=item $w = EV::embed $otherloop, $callback 1120=item $w = EV::embed $otherloop[, $callback]
958 1121
959=item $w = EV::embed_ns $otherloop, $callback 1122=item $w = EV::embed_ns $otherloop[, $callback]
960 1123
961=item $w = $loop->embed ($otherloop, $callback) 1124=item $w = $loop->embed ($otherloop[, $callback])
962 1125
963=item $w = $loop->embed_ns ($otherloop, $callback) 1126=item $w = $loop->embed_ns ($otherloop[, $callback])
964 1127
965Call the callback when the embedded event loop (C<$otherloop>) has any 1128Call the callback when the embedded event loop (C<$otherloop>) has any
966I/O activity. The C<$callback> should alwas be specified as C<undef> in 1129I/O activity. The C<$callback> is optional: if it is missing, then the
967this version of EV, which means the embedded event loop will be managed 1130embedded event loop will be managed automatically (which is recommended),
968automatically. 1131otherwise you have to invoke C<sweep> yourself.
969 1132
970The C<embed_ns> variant doesn't start (activate) the newly created watcher. 1133The C<embed_ns> variant doesn't start (activate) the newly created watcher.
971 1134
972=back 1135=back
973 1136
974=head3 ASYNC WATCHERS - how to wake up another event loop 1137=head3 ASYNC WATCHERS - how to wake up another event loop
975 1138
976Async watchers are provided by EV, but have little use in perl directly, as perl 1139Async watchers are provided by EV, but have little use in perl directly,
977neither supports threads nor direct access to signal handlers or other 1140as perl neither supports threads running in parallel nor direct access to
978contexts where they could be of value. 1141signal handlers or other contexts where they could be of value.
979 1142
980It is, however, possible to use them from the XS level. 1143It is, however, possible to use them from the XS level.
981 1144
982Please see the libev documentation for further details. 1145Please see the libev documentation for further details.
1146
1147=over 4
1148
1149=item $w = EV::async $callback
1150
1151=item $w = EV::async_ns $callback
1152
1153=item $w = $loop->async ($callback)
1154
1155=item $w = $loop->async_ns ($callback)
1156
1157=item $w->send
1158
1159=item $bool = $w->async_pending
1160
1161=back
1162
1163=head3 CLEANUP WATCHERS - how to clean up when the event loop goes away
1164
1165Cleanup watchers are not supported on the Perl level, they can only be
1166used via XS currently.
983 1167
984 1168
985=head1 PERL SIGNALS 1169=head1 PERL SIGNALS
986 1170
987While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour 1171While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
… …
999 my $async_check = EV::check sub { }; 1183 my $async_check = EV::check sub { };
1000 1184
1001This ensures that perl gets into control for a short time to handle any 1185This ensures that perl gets into control for a short time to handle any
1002pending signals, and also ensures (slightly) slower overall operation. 1186pending signals, and also ensures (slightly) slower overall operation.
1003 1187
1004=head1 THREADS 1188=head1 ITHREADS
1005 1189
1006Threads are not supported by this module in any way. Perl pseudo-threads 1190Ithreads are not supported by this module in any way. Perl pseudo-threads
1007is evil stuff and must die. As soon as Perl gains real threads I will work 1191is evil stuff and must die. Real threads as provided by Coro are fully
1008on thread support for it. 1192supported (and enhanced support is available via L<Coro::EV>).
1009 1193
1010=head1 FORK 1194=head1 FORK
1011 1195
1012Most of the "improved" event delivering mechanisms of modern operating 1196Most of the "improved" event delivering mechanisms of modern operating
1013systems have quite a few problems with fork(2) (to put it bluntly: it is 1197systems have quite a few problems with fork(2) (to put it bluntly: it is
… …
1035 1219
10361; 12201;
1037 1221
1038=head1 SEE ALSO 1222=head1 SEE ALSO
1039 1223
1224L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS>
1040L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as 1225(asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as event
1041event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient 1226loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient thread
1042coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP). 1227integration), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1228event-loop agnostic and portable event driven programming.
1043 1229
1044=head1 AUTHOR 1230=head1 AUTHOR
1045 1231
1046 Marc Lehmann <schmorp@schmorp.de> 1232 Marc Lehmann <schmorp@schmorp.de>
1047 http://home.schmorp.de/ 1233 http://home.schmorp.de/
1048 1234
1049=cut 1235=cut
1050 1236

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