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Revision 1.32 by root, Tue Apr 28 00:50:57 2009 UTC vs.
Revision 1.48 by root, Fri Jan 24 13:22:22 2020 UTC

… …
2 EV - perl interface to libev, a high performance full-featured event 2 EV - perl interface to libev, a high performance full-featured event
3 loop 3 loop
4 4
5SYNOPSIS 5SYNOPSIS
6 use EV; 6 use EV;
7 7
8 # TIMERS 8 # TIMERS
9 9
10 my $w = EV::timer 2, 0, sub { 10 my $w = EV::timer 2, 0, sub {
11 warn "is called after 2s"; 11 warn "is called after 2s";
12 }; 12 };
13 13
14 my $w = EV::timer 2, 2, sub { 14 my $w = EV::timer 2, 2, sub {
15 warn "is called roughly every 2s (repeat = 2)"; 15 warn "is called roughly every 2s (repeat = 2)";
16 }; 16 };
17 17
18 undef $w; # destroy event watcher again 18 undef $w; # destroy event watcher again
19 19
20 my $w = EV::periodic 0, 60, 0, sub { 20 my $w = EV::periodic 0, 60, 0, sub {
21 warn "is called every minute, on the minute, exactly"; 21 warn "is called every minute, on the minute, exactly";
22 }; 22 };
23
23 24 # IO
24 # IO 25
25
26 my $w = EV::io *STDIN, EV::READ, sub { 26 my $w = EV::io *STDIN, EV::READ, sub {
27 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask 27 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
28 warn "stdin is readable, you entered: ", <STDIN>; 28 warn "stdin is readable, you entered: ", <STDIN>;
29 }; 29 };
30 30
31 # SIGNALS 31 # SIGNALS
32 32
33 my $w = EV::signal 'QUIT', sub { 33 my $w = EV::signal 'QUIT', sub {
34 warn "sigquit received\n"; 34 warn "sigquit received\n";
35 }; 35 };
36 36
37 # CHILD/PID STATUS CHANGES 37 # CHILD/PID STATUS CHANGES
38 38
39 my $w = EV::child 666, 0, sub { 39 my $w = EV::child 666, 0, sub {
40 my ($w, $revents) = @_; 40 my ($w, $revents) = @_;
41 my $status = $w->rstatus; 41 my $status = $w->rstatus;
42 }; 42 };
43 43
44 # STAT CHANGES 44 # STAT CHANGES
45 my $w = EV::stat "/etc/passwd", 10, sub { 45 my $w = EV::stat "/etc/passwd", 10, sub {
46 my ($w, $revents) = @_; 46 my ($w, $revents) = @_;
47 warn $w->path, " has changed somehow.\n"; 47 warn $w->path, " has changed somehow.\n";
48 }; 48 };
49 49
50 # MAINLOOP 50 # MAINLOOP
51 EV::loop; # loop until EV::unloop is called or all watchers stop 51 EV::run; # loop until EV::break is called or all watchers stop
52 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled 52 EV::run EV::RUN_ONCE; # block until at least one event could be handled
53 EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block 53 EV::run EV::RUN_NOWAIT; # try to handle same events, but do not block
54
55BEFORE YOU START USING THIS MODULE
56 If you only need timer, I/O, signal, child and idle watchers and not the
57 advanced functionality of this module, consider using AnyEvent instead,
58 specifically the simplified API described in AE.
59
60 When used with EV as backend, the AE API is as fast as the native EV
61 API, but your programs/modules will still run with many other event
62 loops.
54 63
55DESCRIPTION 64DESCRIPTION
56 This module provides an interface to libev 65 This module provides an interface to libev
57 (<http://software.schmorp.de/pkg/libev.html>). While the documentation 66 (<http://software.schmorp.de/pkg/libev.html>). While the documentation
58 below is comprehensive, one might also consult the documentation of 67 below is comprehensive, one might also consult the documentation of
… …
66 can use it through the AnyEvent module, stay portable to other event 75 can use it through the AnyEvent module, stay portable to other event
67 loops (if you don't rely on any watcher types not available through it) 76 loops (if you don't rely on any watcher types not available through it)
68 and still be faster than with any other event loop currently supported 77 and still be faster than with any other event loop currently supported
69 in Perl. 78 in Perl.
70 79
80 PORTING FROM EV 3.X to 4.X
81 EV version 4 introduces a number of incompatible changes summarised
82 here. According to the depreciation strategy used by libev, there is a
83 compatibility layer in place so programs should continue to run
84 unchanged (the XS interface lacks this layer, so programs using that one
85 need to be updated).
86
87 This compatibility layer will be switched off in some future release.
88
89 All changes relevant to Perl are renames of symbols, functions and
90 methods:
91
92 EV::loop => EV::run
93 EV::LOOP_NONBLOCK => EV::RUN_NOWAIT
94 EV::LOOP_ONESHOT => EV::RUN_ONCE
95
96 EV::unloop => EV::break
97 EV::UNLOOP_CANCEL => EV::BREAK_CANCEL
98 EV::UNLOOP_ONE => EV::BREAK_ONE
99 EV::UNLOOP_ALL => EV::BREAK_ALL
100
101 EV::TIMEOUT => EV::TIMER
102
103 EV::loop_count => EV::iteration
104 EV::loop_depth => EV::depth
105 EV::loop_verify => EV::verify
106
107 The loop object methods corresponding to the functions above have been
108 similarly renamed.
109
71 MODULE EXPORTS 110 MODULE EXPORTS
72 This module does not export any symbols. 111 This module does not export any symbols.
73 112
74EVENT LOOPS 113EVENT LOOPS
75 EV supports multiple event loops: There is a single "default event loop" 114 EV supports multiple event loops: There is a single "default event loop"
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112 Must be called after a fork in the child, before entering or 151 Must be called after a fork in the child, before entering or
113 continuing the event loop. An alternative is to use 152 continuing the event loop. An alternative is to use
114 "EV::FLAG_FORKCHECK" which calls this function automatically, at 153 "EV::FLAG_FORKCHECK" which calls this function automatically, at
115 some performance loss (refer to the libev documentation). 154 some performance loss (refer to the libev documentation).
116 155
117 $loop->loop_verify 156 $loop->verify
118 Calls "ev_verify" to make internal consistency checks (for debugging 157 Calls "ev_verify" to make internal consistency checks (for debugging
119 libev) and abort the program if any data structures were found to be 158 libev) and abort the program if any data structures were found to be
120 corrupted. 159 corrupted.
121 160
122 $loop = EV::default_loop [$flags] 161 $loop = EV::default_loop [$flags]
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156 195
157 EV::now_update 196 EV::now_update
158 $loop->now_update 197 $loop->now_update
159 Establishes the current time by querying the kernel, updating the 198 Establishes the current time by querying the kernel, updating the
160 time returned by "EV::now" in the progress. This is a costly 199 time returned by "EV::now" in the progress. This is a costly
161 operation and is usually done automatically within "EV::loop". 200 operation and is usually done automatically within "EV::run".
162 201
163 This function is rarely useful, but when some event callback runs 202 This function is rarely useful, but when some event callback runs
164 for a very long time without entering the event loop, updating 203 for a very long time without entering the event loop, updating
165 libev's idea of the current time is a good idea. 204 libev's idea of the current time is a good idea.
166 205
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194 $backend = EV::backend 233 $backend = EV::backend
195 $backend = $loop->backend 234 $backend = $loop->backend
196 Returns an integer describing the backend used by libev 235 Returns an integer describing the backend used by libev
197 (EV::BACKEND_SELECT or EV::BACKEND_EPOLL). 236 (EV::BACKEND_SELECT or EV::BACKEND_EPOLL).
198 237
199 EV::loop [$flags] 238 $active = EV::run [$flags]
200 $loop->loop ([$flags]) 239 $active = $loop->run ([$flags])
201 Begin checking for events and calling callbacks. It returns when a 240 Begin checking for events and calling callbacks. It returns when a
202 callback calls EV::unloop. 241 callback calls EV::break or the flags are nonzero (in which case the
242 return value is true) or when there are no active watchers which
243 reference the loop (keepalive is true), in which case the return
244 value will be false. The return value can generally be interpreted
245 as "if true, there is more work left to do".
203 246
204 The $flags argument can be one of the following: 247 The $flags argument can be one of the following:
205 248
206 0 as above 249 0 as above
207 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 250 EV::RUN_ONCE block at most once (wait, but do not loop)
208 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 251 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
209 252
210 EV::unloop [$how] 253 EV::break [$how]
211 $loop->unloop ([$how]) 254 $loop->break ([$how])
212 When called with no arguments or an argument of EV::UNLOOP_ONE, 255 When called with no arguments or an argument of EV::BREAK_ONE, makes
213 makes the innermost call to EV::loop return. 256 the innermost call to EV::run return.
214 257
215 When called with an argument of EV::UNLOOP_ALL, all calls to 258 When called with an argument of EV::BREAK_ALL, all calls to EV::run
216 EV::loop will return as fast as possible. 259 will return as fast as possible.
217 260
218 $count = EV::loop_count 261 When called with an argument of EV::BREAK_CANCEL, any pending break
219 $count = $loop->loop_count 262 will be cancelled.
263
264 $count = EV::iteration
265 $count = $loop->iteration
220 Return the number of times the event loop has polled for new events. 266 Return the number of times the event loop has polled for new events.
221 Sometimes useful as a generation counter. 267 Sometimes useful as a generation counter.
222 268
223 EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 269 EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
224 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 270 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
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230 "EV::READ | EV::WRITE", indicating the type of I/O event you want to 276 "EV::READ | EV::WRITE", indicating the type of I/O event you want to
231 wait for. If you do not want to wait for some I/O event, specify 277 wait for. If you do not want to wait for some I/O event, specify
232 "undef" for $fh_or_undef and 0 for $events). 278 "undef" for $fh_or_undef and 0 for $events).
233 279
234 If timeout is "undef" or negative, then there will be no timeout. 280 If timeout is "undef" or negative, then there will be no timeout.
235 Otherwise a EV::timer with this value will be started. 281 Otherwise an "EV::timer" with this value will be started.
236 282
237 When an error occurs or either the timeout or I/O watcher triggers, 283 When an error occurs or either the timeout or I/O watcher triggers,
238 then the callback will be called with the received event set (in 284 then the callback will be called with the received event set (in
239 general you can expect it to be a combination of "EV::ERROR", 285 general you can expect it to be a combination of "EV::ERROR",
240 "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). 286 "EV::READ", "EV::WRITE" and "EV::TIMER").
241 287
242 EV::once doesn't return anything: the watchers stay active till 288 EV::once doesn't return anything: the watchers stay active till
243 either of them triggers, then they will be stopped and freed, and 289 either of them triggers, then they will be stopped and freed, and
244 the callback invoked. 290 the callback invoked.
245 291
246 EV::feed_fd_event ($fd, $revents) 292 EV::feed_fd_event $fd, $revents
247 $loop->feed_fd_event ($fd, $revents) 293 $loop->feed_fd_event ($fd, $revents)
248 Feed an event on a file descriptor into EV. EV will react to this 294 Feed an event on a file descriptor into EV. EV will react to this
249 call as if the readyness notifications specified by $revents (a 295 call as if the readyness notifications specified by $revents (a
250 combination of "EV::READ" and "EV::WRITE") happened on the file 296 combination of "EV::READ" and "EV::WRITE") happened on the file
251 descriptor $fd. 297 descriptor $fd.
252 298
253 EV::feed_signal_event ($signal) 299 EV::feed_signal_event $signal
254 Feed a signal event into EV. EV will react to this call as if the 300 Feed a signal event into the default loop. EV will react to this
255 signal specified by $signal had occured. 301 call as if the signal specified by $signal had occured.
302
303 EV::feed_signal $signal
304 Feed a signal event into EV - unlike "EV::feed_signal_event", this
305 works regardless of which loop has registered the signal, and is
306 mainly useful for custom signal implementations.
256 307
257 EV::set_io_collect_interval $time 308 EV::set_io_collect_interval $time
258 $loop->set_io_collect_interval ($time) 309 $loop->set_io_collect_interval ($time)
259 EV::set_timeout_collect_interval $time 310 EV::set_timeout_collect_interval $time
260 $loop->set_timeout_collect_interval ($time) 311 $loop->set_timeout_collect_interval ($time)
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263 the libev documentation at 314 the libev documentation at
264 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT 315 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT
265 ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more 316 ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more
266 detailed discussion. 317 detailed discussion.
267 318
319 $count = EV::pending_count
320 $count = $loop->pending_count
321 Returns the number of currently pending watchers.
322
323 EV::invoke_pending
324 $loop->invoke_pending
325 Invoke all currently pending watchers.
326
268WATCHER OBJECTS 327WATCHER OBJECTS
269 A watcher is an object that gets created to record your interest in some 328 A watcher is an object that gets created to record your interest in some
270 event. For instance, if you want to wait for STDIN to become readable, 329 event. For instance, if you want to wait for STDIN to become readable,
271 you would create an EV::io watcher for that: 330 you would create an EV::io watcher for that:
272 331
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282 341
283 Each watcher type has its associated bit in revents, so you can use the 342 Each watcher type has its associated bit in revents, so you can use the
284 same callback for multiple watchers. The event mask is named after the 343 same callback for multiple watchers. The event mask is named after the
285 type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 344 type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
286 EV::periodic sets EV::PERIODIC and so on, with the exception of I/O 345 EV::periodic sets EV::PERIODIC and so on, with the exception of I/O
287 events (which can set both EV::READ and EV::WRITE bits), and EV::timer 346 events (which can set both EV::READ and EV::WRITE bits).
288 (which uses EV::TIMEOUT).
289 347
290 In the rare case where one wants to create a watcher but not start it at 348 In the rare case where one wants to create a watcher but not start it at
291 the same time, each constructor has a variant with a trailing "_ns" in 349 the same time, each constructor has a variant with a trailing "_ns" in
292 its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. 350 its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
293 351
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356 If the watcher is pending, this function clears its pending status 414 If the watcher is pending, this function clears its pending status
357 and returns its $revents bitset (as if its callback was invoked). If 415 and returns its $revents bitset (as if its callback was invoked). If
358 the watcher isn't pending it does nothing and returns 0. 416 the watcher isn't pending it does nothing and returns 0.
359 417
360 $previous_state = $w->keepalive ($bool) 418 $previous_state = $w->keepalive ($bool)
361 Normally, "EV::loop" will return when there are no active watchers 419 Normally, "EV::run" will return when there are no active watchers
362 (which is a "deadlock" because no progress can be made anymore). 420 (which is a "deadlock" because no progress can be made anymore).
363 This is convinient because it allows you to start your watchers (and 421 This is convenient because it allows you to start your watchers (and
364 your jobs), call "EV::loop" once and when it returns you know that 422 your jobs), call "EV::run" once and when it returns you know that
365 all your jobs are finished (or they forgot to register some watchers 423 all your jobs are finished (or they forgot to register some watchers
366 for their task :). 424 for their task :).
367 425
368 Sometimes, however, this gets in your way, for example when the 426 Sometimes, however, this gets in your way, for example when the
369 module that calls "EV::loop" (usually the main program) is not the 427 module that calls "EV::run" (usually the main program) is not the
370 same module as a long-living watcher (for example a DNS client 428 same module as a long-living watcher (for example a DNS client
371 module written by somebody else even). Then you might want any 429 module written by somebody else even). Then you might want any
372 outstanding requests to be handled, but you would not want to keep 430 outstanding requests to be handled, but you would not want to keep
373 "EV::loop" from returning just because you happen to have this 431 "EV::run" from returning just because you happen to have this
374 long-running UDP port watcher. 432 long-running UDP port watcher.
375 433
376 In this case you can clear the keepalive status, which means that 434 In this case you can clear the keepalive status, which means that
377 even though your watcher is active, it won't keep "EV::loop" from 435 even though your watcher is active, it won't keep "EV::run" from
378 returning. 436 returning.
379 437
380 The initial value for keepalive is true (enabled), and you can 438 The initial value for keepalive is true (enabled), and you can
381 change it any time. 439 change it any time.
382 440
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424 TIMER WATCHERS - relative and optionally repeating timeouts 482 TIMER WATCHERS - relative and optionally repeating timeouts
425 $w = EV::timer $after, $repeat, $callback 483 $w = EV::timer $after, $repeat, $callback
426 $w = EV::timer_ns $after, $repeat, $callback 484 $w = EV::timer_ns $after, $repeat, $callback
427 $w = $loop->timer ($after, $repeat, $callback) 485 $w = $loop->timer ($after, $repeat, $callback)
428 $w = $loop->timer_ns ($after, $repeat, $callback) 486 $w = $loop->timer_ns ($after, $repeat, $callback)
429 Calls the callback after $after seconds (which may be fractional). 487 Calls the callback after $after seconds (which may be fractional or
430 If $repeat is non-zero, the timer will be restarted (with the 488 negative). If $repeat is non-zero, the timer will be restarted (with
431 $repeat value as $after) after the callback returns. 489 the $repeat value as $after) after the callback returns.
432 490
433 This means that the callback would be called roughly after $after 491 This means that the callback would be called roughly after $after
434 seconds, and then every $repeat seconds. The timer does his best not 492 seconds, and then every $repeat seconds. The timer does his best not
435 to drift, but it will not invoke the timer more often then once per 493 to drift, but it will not invoke the timer more often then once per
436 event loop iteration, and might drift in other cases. If that isn't 494 event loop iteration, and might drift in other cases. If that isn't
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443 the same time. 501 the same time.
444 502
445 The "timer_ns" variant doesn't start (activate) the newly created 503 The "timer_ns" variant doesn't start (activate) the newly created
446 watcher. 504 watcher.
447 505
448 $w->set ($after, $repeat) 506 $w->set ($after, $repeat = 0)
449 Reconfigures the watcher, see the constructor above for details. Can 507 Reconfigures the watcher, see the constructor above for details. Can
450 be called at any time. 508 be called at any time.
451 509
452 $w->again 510 $w->again
511 $w->again ($repeat)
453 Similar to the "start" method, but has special semantics for 512 Similar to the "start" method, but has special semantics for
454 repeating timers: 513 repeating timers:
455 514
456 If the timer is active and non-repeating, it will be stopped. 515 If the timer is active and non-repeating, it will be stopped.
457 516
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465 524
466 This behaviour is useful when you have a timeout for some IO 525 This behaviour is useful when you have a timeout for some IO
467 operation. You create a timer object with the same value for $after 526 operation. You create a timer object with the same value for $after
468 and $repeat, and then, in the read/write watcher, run the "again" 527 and $repeat, and then, in the read/write watcher, run the "again"
469 method on the timeout. 528 method on the timeout.
529
530 If called with a $repeat argument, then it uses this a timer repeat
531 value.
532
533 $after = $w->remaining
534 Calculates and returns the remaining time till the timer will fire.
535
536 $repeat = $w->repeat
537 $old_repeat = $w->repeat ($new_repeat)
538 Returns the current value of the repeat attribute and optionally
539 sets a new one. Setting the new one will not restart the watcher -
540 if the watcher is active, the new repeat value is used whenever it
541 expires next.
470 542
471 PERIODIC WATCHERS - to cron or not to cron? 543 PERIODIC WATCHERS - to cron or not to cron?
472 $w = EV::periodic $at, $interval, $reschedule_cb, $callback 544 $w = EV::periodic $at, $interval, $reschedule_cb, $callback
473 $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 545 $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
474 $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback) 546 $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
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491 system time reaches or surpasses this time. 563 system time reaches or surpasses this time.
492 564
493 * repeating interval timer ($interval > 0, $reschedule_cb = 0) 565 * repeating interval timer ($interval > 0, $reschedule_cb = 0)
494 566
495 In this mode the watcher will always be scheduled to time out at 567 In this mode the watcher will always be scheduled to time out at
496 the next "$at + N * $interval" time (for some integer N) and 568 the next "$at + N * $interval" time (for the lowest integer N)
497 then repeat, regardless of any time jumps. 569 and then repeat, regardless of any time jumps. Note that, since
570 "N" can be negative, the first trigger can happen before $at.
498 571
499 This can be used to create timers that do not drift with respect 572 This can be used to create timers that do not drift with respect
500 to system time: 573 to system time:
501 574
502 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; 575 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
503 576
504 That doesn't mean there will always be 3600 seconds in between 577 That doesn't mean there will always be 3600 seconds in between
505 triggers, but only that the the clalback will be called when the 578 triggers, but only that the the callback will be called when the
506 system time shows a full hour (UTC). 579 system time shows a full hour (UTC).
507 580
508 Another way to think about it (for the mathematically inclined) 581 Another way to think about it (for the mathematically inclined)
509 is that EV::periodic will try to run the callback in this mode 582 is that EV::periodic will try to run the callback in this mode
510 at the next possible time where "$time = $at (mod $interval)", 583 at the next possible time where "$time = $at (mod $interval)",
… …
518 first, and the current time as second argument. 591 first, and the current time as second argument.
519 592
520 *This callback MUST NOT stop or destroy this or any other 593 *This callback MUST NOT stop or destroy this or any other
521 periodic watcher, ever, and MUST NOT call any event loop 594 periodic watcher, ever, and MUST NOT call any event loop
522 functions or methods*. If you need to stop it, return 1e30 and 595 functions or methods*. If you need to stop it, return 1e30 and
523 stop it afterwards. You may create and start a "EV::prepare" 596 stop it afterwards. You may create and start an "EV::prepare"
524 watcher for this task. 597 watcher for this task.
525 598
526 It must return the next time to trigger, based on the passed 599 It must return the next time to trigger, based on the passed
527 time value (that is, the lowest time value larger than or equal 600 time value (that is, the lowest time value larger than or equal
528 to to the second argument). It will usually be called just 601 to to the second argument). It will usually be called just
529 before the callback will be triggered, but might be called at 602 before the callback will be triggered, but might be called at
530 other times, too. 603 other times, too.
531 604
532 This can be used to create very complex timers, such as a timer 605 This can be used to create very complex timers, such as a timer
533 that triggers on each midnight, local time (actually 24 hours 606 that triggers on each midnight, local time (actually one day
534 after the last midnight, to keep the example simple. If you know 607 after the last midnight, to keep the example simple):
535 a way to do it correctly in about the same space (without
536 requiring elaborate modules), drop me a note :):
537 608
538 my $daily = EV::periodic 0, 0, sub { 609 my $daily = EV::periodic 0, 0, sub {
539 my ($w, $now) = @_; 610 my ($w, $now) = @_;
540 611
541 use Time::Local (); 612 use Time::Local ();
542 my (undef, undef, undef, $d, $m, $y) = localtime $now; 613 my (undef, undef, undef, $d, $m, $y) = localtime $now;
543 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y 614 Time::Local::timelocal_nocheck 0, 0, 0, $d + 1, $m, $y
544 }, sub { 615 }, sub {
545 print "it's midnight or likely shortly after, now\n"; 616 print "it's midnight or likely shortly after, now\n";
546 }; 617 };
547 618
548 The "periodic_ns" variant doesn't start (activate) the newly created 619 The "periodic_ns" variant doesn't start (activate) the newly created
… …
556 Simply stops and starts the watcher again. 627 Simply stops and starts the watcher again.
557 628
558 $time = $w->at 629 $time = $w->at
559 Return the time that the watcher is expected to trigger next. 630 Return the time that the watcher is expected to trigger next.
560 631
632 $offset = $w->offset
633 $old_offset = $w->offset ($new_offset)
634 Returns the current value of the offset attribute and optionally
635 sets a new one. Setting the new one will not restart the watcher -
636 if the watcher is active, the new offset value is used whenever it
637 expires next.
638
639 $interval = $w->interval
640 $old_interval = $w->interval ($new_interval)
641 See above, for the interval attribute.
642
643 $reschedule_cb = $w->reschedule_cb
644 $old_reschedule_cb = $w->reschedule_cb ($new_reschedule_cb)
645 See above, for the reschedule callback.
646
561 SIGNAL WATCHERS - signal me when a signal gets signalled! 647 SIGNAL WATCHERS - signal me when a signal gets signalled!
562 $w = EV::signal $signal, $callback 648 $w = EV::signal $signal, $callback
563 $w = EV::signal_ns $signal, $callback 649 $w = EV::signal_ns $signal, $callback
650 $w = $loop->signal ($signal, $callback)
651 $w = $loop->signal_ns ($signal, $callback)
564 Call the callback when $signal is received (the signal can be 652 Call the callback when $signal is received (the signal can be
565 specified by number or by name, just as with "kill" or %SIG). 653 specified by number or by name, just as with "kill" or %SIG).
654
655 Only one event loop can grab a given signal - attempting to grab the
656 same signal from two EV loops will crash the program immediately or
657 cause data corruption.
566 658
567 EV will grab the signal for the process (the kernel only allows one 659 EV will grab the signal for the process (the kernel only allows one
568 component to receive a signal at a time) when you start a signal 660 component to receive a signal at a time) when you start a signal
569 watcher, and removes it again when you stop it. Perl does the same 661 watcher, and removes it again when you stop it. Perl does the same
570 when you add/remove callbacks to %SIG, so watch out. 662 when you add/remove callbacks to %SIG, so watch out.
… …
744 $w = $loop->check_ns ($callback) 836 $w = $loop->check_ns ($callback)
745 Call the callback just after the process wakes up again (after it 837 Call the callback just after the process wakes up again (after it
746 has gathered events), but before any other callbacks have been 838 has gathered events), but before any other callbacks have been
747 invoked. 839 invoked.
748 840
749 This is used to integrate other event-based software into the EV 841 This can be used to integrate other event-based software into the EV
750 mainloop: You register a prepare callback and in there, you create 842 mainloop: You register a prepare callback and in there, you create
751 io and timer watchers as required by the other software. Here is a 843 io and timer watchers as required by the other software. Here is a
752 real-world example of integrating Net::SNMP (with some details left 844 real-world example of integrating Net::SNMP (with some details left
753 out): 845 out):
754 846
… …
790 watchers are destroyed before this can happen (remember EV::check 882 watchers are destroyed before this can happen (remember EV::check
791 gets called first). 883 gets called first).
792 884
793 The "check_ns" variant doesn't start (activate) the newly created 885 The "check_ns" variant doesn't start (activate) the newly created
794 watcher. 886 watcher.
887
888 EV::CHECK constant issues
889 Like all other watcher types, there is a bitmask constant for use in
890 $revents and other places. The "EV::CHECK" is special as it has the
891 same name as the "CHECK" sub called by Perl. This doesn't cause big
892 issues on newer perls (beginning with 5.8.9), but it means thatthe
893 constant must be *inlined*, i.e. runtime calls will not work. That
894 means that as long as you always "use EV" and then "EV::CHECK" you
895 are on the safe side.
795 896
796 FORK WATCHERS - the audacity to resume the event loop after a fork 897 FORK WATCHERS - the audacity to resume the event loop after a fork
797 Fork watchers are called when a "fork ()" was detected. The invocation 898 Fork watchers are called when a "fork ()" was detected. The invocation
798 is done before the event loop blocks next and before "check" watchers 899 is done before the event loop blocks next and before "check" watchers
799 are being called, and only in the child after the fork. 900 are being called, and only in the child after the fork.
… …
820 921
821 In short, this watcher is most useful on BSD systems without working 922 In short, this watcher is most useful on BSD systems without working
822 kqueue to still be able to handle a large number of sockets: 923 kqueue to still be able to handle a large number of sockets:
823 924
824 my $socket_loop; 925 my $socket_loop;
825 926
826 # check wether we use SELECT or POLL _and_ KQUEUE is supported 927 # check wether we use SELECT or POLL _and_ KQUEUE is supported
827 if ( 928 if (
828 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 929 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
829 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 930 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
830 ) { 931 ) {
831 # use kqueue for sockets 932 # use kqueue for sockets
832 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 933 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
833 } 934 }
834 935
835 # use the default loop otherwise 936 # use the default loop otherwise
836 $socket_loop ||= EV::default_loop; 937 $socket_loop ||= EV::default_loop;
837 938
838 $w = EV::embed $otherloop[, $callback] 939 $w = EV::embed $otherloop[, $callback]
839 $w = EV::embed_ns $otherloop[, $callback] 940 $w = EV::embed_ns $otherloop[, $callback]
840 $w = $loop->embed ($otherloop[, $callback]) 941 $w = $loop->embed ($otherloop[, $callback])
… …
847 The "embed_ns" variant doesn't start (activate) the newly created 948 The "embed_ns" variant doesn't start (activate) the newly created
848 watcher. 949 watcher.
849 950
850 ASYNC WATCHERS - how to wake up another event loop 951 ASYNC WATCHERS - how to wake up another event loop
851 Async watchers are provided by EV, but have little use in perl directly, 952 Async watchers are provided by EV, but have little use in perl directly,
852 as perl neither supports threads nor direct access to signal handlers or 953 as perl neither supports threads running in parallel nor direct access
853 other contexts where they could be of value. 954 to signal handlers or other contexts where they could be of value.
854 955
855 It is, however, possible to use them from the XS level. 956 It is, however, possible to use them from the XS level.
856 957
857 Please see the libev documentation for further details. 958 Please see the libev documentation for further details.
858 959
859 $w = EV::async $callback 960 $w = EV::async $callback
860 $w = EV::async_ns $callback 961 $w = EV::async_ns $callback
962 $w = $loop->async ($callback)
963 $w = $loop->async_ns ($callback)
861 $w->send 964 $w->send
862 $bool = $w->async_pending 965 $bool = $w->async_pending
966
967 CLEANUP WATCHERS - how to clean up when the event loop goes away
968 Cleanup watchers are not supported on the Perl level, they can only be
969 used via XS currently.
863 970
864PERL SIGNALS 971PERL SIGNALS
865 While Perl signal handling (%SIG) is not affected by EV, the behaviour 972 While Perl signal handling (%SIG) is not affected by EV, the behaviour
866 with EV is as the same as any other C library: Perl-signals will only be 973 with EV is as the same as any other C library: Perl-signals will only be
867 handled when Perl runs, which means your signal handler might be invoked 974 handled when Perl runs, which means your signal handler might be invoked
… …
877 my $async_check = EV::check sub { }; 984 my $async_check = EV::check sub { };
878 985
879 This ensures that perl gets into control for a short time to handle any 986 This ensures that perl gets into control for a short time to handle any
880 pending signals, and also ensures (slightly) slower overall operation. 987 pending signals, and also ensures (slightly) slower overall operation.
881 988
882THREADS 989ITHREADS
883 Threads are not supported by this module in any way. Perl pseudo-threads 990 Ithreads are not supported by this module in any way. Perl
884 is evil stuff and must die. As soon as Perl gains real threads I will 991 pseudo-threads is evil stuff and must die. Real threads as provided by
885 work on thread support for it. 992 Coro are fully supported (and enhanced support is available via
993 Coro::EV).
886 994
887FORK 995FORK
888 Most of the "improved" event delivering mechanisms of modern operating 996 Most of the "improved" event delivering mechanisms of modern operating
889 systems have quite a few problems with fork(2) (to put it bluntly: it is 997 systems have quite a few problems with fork(2) (to put it bluntly: it is
890 not supported and usually destructive). Libev makes it possible to work 998 not supported and usually destructive). Libev makes it possible to work
… …
900 1008
901 On win32, there is no notion of fork so all this doesn't apply, of 1009 On win32, there is no notion of fork so all this doesn't apply, of
902 course. 1010 course.
903 1011
904SEE ALSO 1012SEE ALSO
905 EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event 1013 EV::MakeMaker - MakeMaker interface to XS API, EV::ADNS (asynchronous
906 loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines 1014 DNS), Glib::EV (makes Glib/Gtk2 use EV as event loop), EV::Glib (embed
907 with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop 1015 Glib into EV), Coro::EV (efficient thread integration), Net::SNMP::EV
908 agnostic and portable event driven programming. 1016 (asynchronous SNMP), AnyEvent for event-loop agnostic and portable event
1017 driven programming.
909 1018
910AUTHOR 1019AUTHOR
911 Marc Lehmann <schmorp@schmorp.de> 1020 Marc Lehmann <schmorp@schmorp.de>
912 http://home.schmorp.de/ 1021 http://home.schmorp.de/
913 1022

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