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Revision 1.49 by root, Thu Oct 19 17:22:50 2023 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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84 default loop as this is fastest (perl-wise), best supported by other 123 default loop as this is fastest (perl-wise), best supported by other
85 modules (e.g. AnyEvent or Coro) and most portable event loop. 124 modules (e.g. AnyEvent or Coro) and most portable event loop.
86 125
87 For specific programs you can create additional event loops dynamically. 126 For specific programs you can create additional event loops dynamically.
88 127
89 If you want to take avdantage of kqueue (which often works properly for 128 If you want to take advantage of kqueue (which often works properly for
90 sockets only) even though the default loop doesn't enable it, you can 129 sockets only) even though the default loop doesn't enable it, you can
91 *embed* a kqueue loop into the default loop: running the default loop 130 *embed* a kqueue loop into the default loop: running the default loop
92 will then also service the kqueue loop to some extent. See the example 131 will then also service the kqueue loop to some extent. See the example
93 in the section about embed watchers for an example on how to achieve 132 in the section about embed watchers for an example on how to achieve
94 that. 133 that.
95 134
96 $loop = new EV::loop [$flags] 135 $loop = new EV::Loop [$flags]
97 Create a new event loop as per the specified flags. Please refer to 136 Create a new event loop as per the specified flags. Please refer to
98 the "ev_loop_new ()" function description in the libev documentation 137 the "ev_loop_new ()" function description in the libev documentation
99 (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI 138 (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI
100 ONS>, or locally-installed as EV::libev manpage) for more info. 139 ONS>, or locally-installed as EV::libev manpage) for more info.
101 140
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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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149 Returns the current time in (fractional) seconds since the epoch. 188 Returns the current time in (fractional) seconds since the epoch.
150 189
151 $time = EV::now 190 $time = EV::now
152 $time = $loop->now 191 $time = $loop->now
153 Returns the time the last event loop iteration has been started. 192 Returns the time the last event loop iteration has been started.
154 This is the time that (relative) timers are based on, and refering 193 This is the time that (relative) timers are based on, and referring
155 to it is usually faster then calling EV::time. 194 to it is usually faster then calling EV::time.
195
196 EV::now_update
197 $loop->now_update
198 Establishes the current time by querying the kernel, updating the
199 time returned by "EV::now" in the progress. This is a costly
200 operation and is usually done automatically within "EV::run".
201
202 This function is rarely useful, but when some event callback runs
203 for a very long time without entering the event loop, updating
204 libev's idea of the current time is a good idea.
205
206 EV::suspend
207 $loop->suspend
208 EV::resume
209 $loop->resume
210 These two functions suspend and resume a loop, for use when the loop
211 is not used for a while and timeouts should not be processed.
212
213 A typical use case would be an interactive program such as a game:
214 When the user presses "^Z" to suspend the game and resumes it an
215 hour later it would be best to handle timeouts as if no time had
216 actually passed while the program was suspended. This can be
217 achieved by calling "suspend" in your "SIGTSTP" handler, sending
218 yourself a "SIGSTOP" and calling "resume" directly afterwards to
219 resume timer processing.
220
221 Effectively, all "timer" watchers will be delayed by the time spend
222 between "suspend" and "resume", and all "periodic" watchers will be
223 rescheduled (that is, they will lose any events that would have
224 occured while suspended).
225
226 After calling "suspend" you must not call *any* function on the
227 given loop other than "resume", and you must not call "resume"
228 without a previous call to "suspend".
229
230 Calling "suspend"/"resume" has the side effect of updating the event
231 loop time (see "now_update").
156 232
157 $backend = EV::backend 233 $backend = EV::backend
158 $backend = $loop->backend 234 $backend = $loop->backend
159 Returns an integer describing the backend used by libev 235 Returns an integer describing the backend used by libev
160 (EV::METHOD_SELECT or EV::METHOD_EPOLL). 236 (EV::BACKEND_SELECT or EV::BACKEND_EPOLL).
161 237
162 EV::loop [$flags] 238 $active = EV::run [$flags]
163 $loop->loop ([$flags]) 239 $active = $loop->run ([$flags])
164 Begin checking for events and calling callbacks. It returns when a 240 Begin checking for events and calling callbacks. It returns when a
165 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".
166 246
167 The $flags argument can be one of the following: 247 The $flags argument can be one of the following:
168 248
169 0 as above 249 0 as above
170 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 250 EV::RUN_ONCE block at most once (wait, but do not loop)
171 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 251 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
172 252
173 EV::unloop [$how] 253 EV::break [$how]
174 $loop->unloop ([$how]) 254 $loop->break ([$how])
175 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
176 makes the innermost call to EV::loop return. 256 the innermost call to EV::run return.
177 257
178 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
179 EV::loop will return as fast as possible. 259 will return as fast as possible.
180 260
181 $count = EV::loop_count 261 When called with an argument of EV::BREAK_CANCEL, any pending break
182 $count = $loop->loop_count 262 will be cancelled.
263
264 $count = EV::iteration
265 $count = $loop->iteration
183 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.
184 Sometiems useful as a generation counter. 267 Sometimes useful as a generation counter.
185 268
186 EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 269 EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
187 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 270 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
188 This function rolls together an I/O and a timer watcher for a single 271 This function rolls together an I/O and a timer watcher for a single
189 one-shot event without the need for managing a watcher object. 272 one-shot event without the need for managing a watcher object.
… …
193 "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
194 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
195 "undef" for $fh_or_undef and 0 for $events). 278 "undef" for $fh_or_undef and 0 for $events).
196 279
197 If timeout is "undef" or negative, then there will be no timeout. 280 If timeout is "undef" or negative, then there will be no timeout.
198 Otherwise a EV::timer with this value will be started. 281 Otherwise an "EV::timer" with this value will be started.
199 282
200 When an error occurs or either the timeout or I/O watcher triggers, 283 When an error occurs or either the timeout or I/O watcher triggers,
201 then the callback will be called with the received event set (in 284 then the callback will be called with the received event set (in
202 general you can expect it to be a combination of "EV::ERROR", 285 general you can expect it to be a combination of "EV::ERROR",
203 "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). 286 "EV::READ", "EV::WRITE" and "EV::TIMER").
204 287
205 EV::once doesn't return anything: the watchers stay active till 288 EV::once doesn't return anything: the watchers stay active till
206 either of them triggers, then they will be stopped and freed, and 289 either of them triggers, then they will be stopped and freed, and
207 the callback invoked. 290 the callback invoked.
208 291
209 EV::feed_fd_event ($fd, $revents) 292 EV::feed_fd_event $fd, $revents
210 $loop->feed_fd_event ($fd, $revents) 293 $loop->feed_fd_event ($fd, $revents)
211 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
212 call as if the readyness notifications specified by $revents (a 295 call as if the readyness notifications specified by $revents (a
213 combination of "EV::READ" and "EV::WRITE") happened on the file 296 combination of "EV::READ" and "EV::WRITE") happened on the file
214 descriptor $fd. 297 descriptor $fd.
215 298
216 EV::feed_signal_event ($signal) 299 EV::feed_signal_event $signal
217 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
218 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.
219 307
220 EV::set_io_collect_interval $time 308 EV::set_io_collect_interval $time
221 $loop->set_io_collect_interval ($time) 309 $loop->set_io_collect_interval ($time)
222 EV::set_timeout_collect_interval $time 310 EV::set_timeout_collect_interval $time
223 $loop->set_timeout_collect_interval ($time) 311 $loop->set_timeout_collect_interval ($time)
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226 the libev documentation at 314 the libev documentation at
227 <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
228 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
229 detailed discussion. 317 detailed discussion.
230 318
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
231WATCHER OBJECTS 327WATCHER OBJECTS
232 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
233 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,
234 you would create an EV::io watcher for that: 330 you would create an EV::io watcher for that:
235 331
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243 will be called with at least two arguments: the watcher and a bitmask of 339 will be called with at least two arguments: the watcher and a bitmask of
244 received events. 340 received events.
245 341
246 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
247 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
248 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,
249 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
250 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).
251 (which uses EV::TIMEOUT).
252 347
253 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
254 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
255 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.
256 351
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319 If the watcher is pending, this function clears its pending status 414 If the watcher is pending, this function clears its pending status
320 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
321 the watcher isn't pending it does nothing and returns 0. 416 the watcher isn't pending it does nothing and returns 0.
322 417
323 $previous_state = $w->keepalive ($bool) 418 $previous_state = $w->keepalive ($bool)
324 Normally, "EV::loop" will return when there are no active watchers 419 Normally, "EV::run" will return when there are no active watchers
325 (which is a "deadlock" because no progress can be made anymore). 420 (which is a "deadlock" because no progress can be made anymore).
326 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
327 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
328 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
329 for their task :). 424 for their task :).
330 425
331 Sometimes, however, this gets in your way, for example when the 426 Sometimes, however, this gets in your way, for example when the
332 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
333 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
334 module written by somebody else even). Then you might want any 429 module written by somebody else even). Then you might want any
335 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
336 "EV::loop" from returning just because you happen to have this 431 "EV::run" from returning just because you happen to have this
337 long-running UDP port watcher. 432 long-running UDP port watcher.
338 433
339 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
340 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
341 returning. 436 returning.
342 437
343 The initial value for keepalive is true (enabled), and you cna 438 The initial value for keepalive is true (enabled), and you can
344 change it any time. 439 change it any time.
345 440
346 Example: Register an I/O watcher for some UDP socket but do not keep 441 Example: Register an I/O watcher for some UDP socket but do not keep
347 the event loop from running just because of that watcher. 442 the event loop from running just because of that watcher.
348 443
… …
387 TIMER WATCHERS - relative and optionally repeating timeouts 482 TIMER WATCHERS - relative and optionally repeating timeouts
388 $w = EV::timer $after, $repeat, $callback 483 $w = EV::timer $after, $repeat, $callback
389 $w = EV::timer_ns $after, $repeat, $callback 484 $w = EV::timer_ns $after, $repeat, $callback
390 $w = $loop->timer ($after, $repeat, $callback) 485 $w = $loop->timer ($after, $repeat, $callback)
391 $w = $loop->timer_ns ($after, $repeat, $callback) 486 $w = $loop->timer_ns ($after, $repeat, $callback)
392 Calls the callback after $after seconds (which may be fractional). 487 Calls the callback after $after seconds (which may be fractional or
393 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
394 $repeat value as $after) after the callback returns. 489 the $repeat value as $after) after the callback returns.
395 490
396 This means that the callback would be called roughly after $after 491 This means that the callback would be called roughly after $after
397 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
398 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
399 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
… …
406 the same time. 501 the same time.
407 502
408 The "timer_ns" variant doesn't start (activate) the newly created 503 The "timer_ns" variant doesn't start (activate) the newly created
409 watcher. 504 watcher.
410 505
411 $w->set ($after, $repeat) 506 $w->set ($after, $repeat = 0)
412 Reconfigures the watcher, see the constructor above for details. Can 507 Reconfigures the watcher, see the constructor above for details. Can
413 be called at any time. 508 be called at any time.
414 509
415 $w->again 510 $w->again
511 $w->again ($repeat)
416 Similar to the "start" method, but has special semantics for 512 Similar to the "start" method, but has special semantics for
417 repeating timers: 513 repeating timers:
418 514
419 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.
420 516
… …
428 524
429 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
430 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
431 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"
432 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.
433 542
434 PERIODIC WATCHERS - to cron or not to cron? 543 PERIODIC WATCHERS - to cron or not to cron?
435 $w = EV::periodic $at, $interval, $reschedule_cb, $callback 544 $w = EV::periodic $at, $interval, $reschedule_cb, $callback
436 $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 545 $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
437 $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback) 546 $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
… …
454 system time reaches or surpasses this time. 563 system time reaches or surpasses this time.
455 564
456 * repeating interval timer ($interval > 0, $reschedule_cb = 0) 565 * repeating interval timer ($interval > 0, $reschedule_cb = 0)
457 566
458 In this mode the watcher will always be scheduled to time out at 567 In this mode the watcher will always be scheduled to time out at
459 the next "$at + N * $interval" time (for some integer N) and 568 the next "$at + N * $interval" time (for the lowest integer N)
460 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.
461 571
462 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
463 to system time: 573 to system time:
464 574
465 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; 575 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
466 576
467 That doesn't mean there will always be 3600 seconds in between 577 That doesn't mean there will always be 3600 seconds in between
468 triggers, but only that the the clalback will be called when the 578 triggers, but only that the the callback will be called when the
469 system time shows a full hour (UTC). 579 system time shows a full hour (UTC).
470 580
471 Another way to think about it (for the mathematically inclined) 581 Another way to think about it (for the mathematically inclined)
472 is that EV::periodic will try to run the callback in this mode 582 is that EV::periodic will try to run the callback in this mode
473 at the next possible time where "$time = $at (mod $interval)", 583 at the next possible time where "$time = $at (mod $interval)",
… …
481 first, and the current time as second argument. 591 first, and the current time as second argument.
482 592
483 *This callback MUST NOT stop or destroy this or any other 593 *This callback MUST NOT stop or destroy this or any other
484 periodic watcher, ever, and MUST NOT call any event loop 594 periodic watcher, ever, and MUST NOT call any event loop
485 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
486 stop it afterwards. You may create and start a "EV::prepare" 596 stop it afterwards. You may create and start an "EV::prepare"
487 watcher for this task. 597 watcher for this task.
488 598
489 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
490 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
491 to to the second argument). It will usually be called just 601 to to the second argument). It will usually be called just
492 before the callback will be triggered, but might be called at 602 before the callback will be triggered, but might be called at
493 other times, too. 603 other times, too.
494 604
495 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
496 that triggers on each midnight, local time (actually 24 hours 606 that triggers on each midnight, local time (actually one day
497 after the last midnight, to keep the example simple. If you know 607 after the last midnight, to keep the example simple):
498 a way to do it correctly in about the same space (without
499 requiring elaborate modules), drop me a note :):
500 608
501 my $daily = EV::periodic 0, 0, sub { 609 my $daily = EV::periodic 0, 0, sub {
502 my ($w, $now) = @_; 610 my ($w, $now) = @_;
503 611
504 use Time::Local (); 612 use Time::Local ();
505 my (undef, undef, undef, $d, $m, $y) = localtime $now; 613 my (undef, undef, undef, $d, $m, $y) = localtime $now;
506 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y 614 Time::Local::timelocal_nocheck 0, 0, 0, $d + 1, $m, $y
507 }, sub { 615 }, sub {
508 print "it's midnight or likely shortly after, now\n"; 616 print "it's midnight or likely shortly after, now\n";
509 }; 617 };
510 618
511 The "periodic_ns" variant doesn't start (activate) the newly created 619 The "periodic_ns" variant doesn't start (activate) the newly created
… …
519 Simply stops and starts the watcher again. 627 Simply stops and starts the watcher again.
520 628
521 $time = $w->at 629 $time = $w->at
522 Return the time that the watcher is expected to trigger next. 630 Return the time that the watcher is expected to trigger next.
523 631
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
524 SIGNAL WATCHERS - signal me when a signal gets signalled! 647 SIGNAL WATCHERS - signal me when a signal gets signalled!
525 $w = EV::signal $signal, $callback 648 $w = EV::signal $signal, $callback
526 $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)
527 Call the callback when $signal is received (the signal can be 652 Call the callback when $signal is received (the signal can be
528 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.
529 658
530 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
531 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
532 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
533 when you add/remove callbacks to %SIG, so watch out. 662 when you add/remove callbacks to %SIG, so watch out.
… …
587 716
588 $pid = $w->rpid 717 $pid = $w->rpid
589 Return the pid of the awaited child (useful when you have installed 718 Return the pid of the awaited child (useful when you have installed
590 a watcher for all pids). 719 a watcher for all pids).
591 720
721 EV::Child::reinit [EXPERIMENTAL]
722 Internally, libev installs a signal handler for "SIGCHLD".
723 Unfortunately, a lot of Perl code does soemthing like "local
724 $SIG{CHLD}", which, unfortunately, is broken and will not restore
725 the signal handler.
726
727 If this has happened, you can call this function to stop/rrestart
728 the internal libev watcher, which will reset the signal handler.
729
730 Note that this is an experimental function, whose interface might
731 change.
732
592 STAT WATCHERS - did the file attributes just change? 733 STAT WATCHERS - did the file attributes just change?
593 $w = EV::stat $path, $interval, $callback 734 $w = EV::stat $path, $interval, $callback
594 $w = EV::stat_ns $path, $interval, $callback 735 $w = EV::stat_ns $path, $interval, $callback
595 $w = $loop->stat ($path, $interval, $callback) 736 $w = $loop->stat ($path, $interval, $callback)
596 $w = $loop->stat_ns ($path, $interval, $callback) 737 $w = $loop->stat_ns ($path, $interval, $callback)
… …
707 $w = $loop->check_ns ($callback) 848 $w = $loop->check_ns ($callback)
708 Call the callback just after the process wakes up again (after it 849 Call the callback just after the process wakes up again (after it
709 has gathered events), but before any other callbacks have been 850 has gathered events), but before any other callbacks have been
710 invoked. 851 invoked.
711 852
712 This is used to integrate other event-based software into the EV 853 This can be used to integrate other event-based software into the EV
713 mainloop: You register a prepare callback and in there, you create 854 mainloop: You register a prepare callback and in there, you create
714 io and timer watchers as required by the other software. Here is a 855 io and timer watchers as required by the other software. Here is a
715 real-world example of integrating Net::SNMP (with some details left 856 real-world example of integrating Net::SNMP (with some details left
716 out): 857 out):
717 858
… …
748 # make the dispatcher handle any new stuff 889 # make the dispatcher handle any new stuff
749 ... not shown 890 ... not shown
750 }; 891 };
751 892
752 The callbacks of the created watchers will not be called as the 893 The callbacks of the created watchers will not be called as the
753 watchers are destroyed before this cna happen (remember EV::check 894 watchers are destroyed before this can happen (remember EV::check
754 gets called first). 895 gets called first).
755 896
756 The "check_ns" variant doesn't start (activate) the newly created 897 The "check_ns" variant doesn't start (activate) the newly created
757 watcher. 898 watcher.
899
900 EV::CHECK constant issues
901 Like all other watcher types, there is a bitmask constant for use in
902 $revents and other places. The "EV::CHECK" is special as it has the
903 same name as the "CHECK" sub called by Perl. This doesn't cause big
904 issues on newer perls (beginning with 5.8.9), but it means thatthe
905 constant must be *inlined*, i.e. runtime calls will not work. That
906 means that as long as you always "use EV" and then "EV::CHECK" you
907 are on the safe side.
758 908
759 FORK WATCHERS - the audacity to resume the event loop after a fork 909 FORK WATCHERS - the audacity to resume the event loop after a fork
760 Fork watchers are called when a "fork ()" was detected. The invocation 910 Fork watchers are called when a "fork ()" was detected. The invocation
761 is done before the event loop blocks next and before "check" watchers 911 is done before the event loop blocks next and before "check" watchers
762 are being called, and only in the child after the fork. 912 are being called, and only in the child after the fork.
… …
783 933
784 In short, this watcher is most useful on BSD systems without working 934 In short, this watcher is most useful on BSD systems without working
785 kqueue to still be able to handle a large number of sockets: 935 kqueue to still be able to handle a large number of sockets:
786 936
787 my $socket_loop; 937 my $socket_loop;
788 938
789 # check wether we use SELECT or POLL _and_ KQUEUE is supported 939 # check wether we use SELECT or POLL _and_ KQUEUE is supported
790 if ( 940 if (
791 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 941 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
792 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 942 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
793 ) { 943 ) {
794 # use kqueue for sockets 944 # use kqueue for sockets
795 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 945 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
796 } 946 }
797 947
798 # use the default loop otherwise 948 # use the default loop otherwise
799 $socket_loop ||= EV::default_loop; 949 $socket_loop ||= EV::default_loop;
800 950
801 $w = EV::embed $otherloop[, $callback] 951 $w = EV::embed $otherloop[, $callback]
802 $w = EV::embed_ns $otherloop[, $callback] 952 $w = EV::embed_ns $otherloop[, $callback]
803 $w = $loop->embed ($otherloop[, $callback]) 953 $w = $loop->embed ($otherloop[, $callback])
… …
810 The "embed_ns" variant doesn't start (activate) the newly created 960 The "embed_ns" variant doesn't start (activate) the newly created
811 watcher. 961 watcher.
812 962
813 ASYNC WATCHERS - how to wake up another event loop 963 ASYNC WATCHERS - how to wake up another event loop
814 Async watchers are provided by EV, but have little use in perl directly, 964 Async watchers are provided by EV, but have little use in perl directly,
815 as perl neither supports threads nor direct access to signal handlers or 965 as perl neither supports threads running in parallel nor direct access
816 other contexts where they could be of value. 966 to signal handlers or other contexts where they could be of value.
817 967
818 It is, however, possible to use them from the XS level. 968 It is, however, possible to use them from the XS level.
819 969
820 Please see the libev documentation for further details. 970 Please see the libev documentation for further details.
821 971
822 $w = EV::async $callback 972 $w = EV::async $callback
823 $w = EV::async_ns $callback 973 $w = EV::async_ns $callback
974 $w = $loop->async ($callback)
975 $w = $loop->async_ns ($callback)
824 $w->send 976 $w->send
825 $bool = $w->async_pending 977 $bool = $w->async_pending
978
979 CLEANUP WATCHERS - how to clean up when the event loop goes away
980 Cleanup watchers are not supported on the Perl level, they can only be
981 used via XS currently.
826 982
827PERL SIGNALS 983PERL SIGNALS
828 While Perl signal handling (%SIG) is not affected by EV, the behaviour 984 While Perl signal handling (%SIG) is not affected by EV, the behaviour
829 with EV is as the same as any other C library: Perl-signals will only be 985 with EV is as the same as any other C library: Perl-signals will only be
830 handled when Perl runs, which means your signal handler might be invoked 986 handled when Perl runs, which means your signal handler might be invoked
… …
840 my $async_check = EV::check sub { }; 996 my $async_check = EV::check sub { };
841 997
842 This ensures that perl gets into control for a short time to handle any 998 This ensures that perl gets into control for a short time to handle any
843 pending signals, and also ensures (slightly) slower overall operation. 999 pending signals, and also ensures (slightly) slower overall operation.
844 1000
845THREADS 1001ITHREADS
846 Threads are not supported by this module in any way. Perl pseudo-threads 1002 Ithreads are not supported by this module in any way. Perl
847 is evil stuff and must die. As soon as Perl gains real threads I will 1003 pseudo-threads is evil stuff and must die. Real threads as provided by
848 work on thread support for it. 1004 Coro are fully supported (and enhanced support is available via
1005 Coro::EV).
849 1006
850FORK 1007FORK
851 Most of the "improved" event delivering mechanisms of modern operating 1008 Most of the "improved" event delivering mechanisms of modern operating
852 systems have quite a few problems with fork(2) (to put it bluntly: it is 1009 systems have quite a few problems with fork(2) (to put it bluntly: it is
853 not supported and usually destructive). Libev makes it possible to work 1010 not supported and usually destructive). Libev makes it possible to work
… …
863 1020
864 On win32, there is no notion of fork so all this doesn't apply, of 1021 On win32, there is no notion of fork so all this doesn't apply, of
865 course. 1022 course.
866 1023
867SEE ALSO 1024SEE ALSO
868 EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event 1025 EV::MakeMaker - MakeMaker interface to XS API, EV::ADNS (asynchronous
869 loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines 1026 DNS), Glib::EV (makes Glib/Gtk2 use EV as event loop), EV::Glib (embed
870 with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop 1027 Glib into EV), Coro::EV (efficient thread integration), Net::SNMP::EV
871 agnostic and portable event driven programming. 1028 (asynchronous SNMP), AnyEvent for event-loop agnostic and portable event
1029 driven programming.
872 1030
873AUTHOR 1031AUTHOR
874 Marc Lehmann <schmorp@schmorp.de> 1032 Marc Lehmann <schmorp@schmorp.de>
875 http://home.schmorp.de/ 1033 http://home.schmorp.de/
876 1034

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