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… …
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
59 libev itself (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>) 68 libev itself (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
60 for more subtle details on watcher semantics or some discussion on the 69 perldoc EV::libev) for more subtle details on watcher semantics or some
61 available backends, or how to force a specific backend with 70 discussion on the available backends, or how to force a specific backend
62 "LIBEV_FLAGS", or just about in any case because it has much more 71 with "LIBEV_FLAGS", or just about in any case because it has much more
63 detailed information. 72 detailed information.
64 73
65 This module is very fast and scalable. It is actually so fast that you 74 This module is very fast and scalable. It is actually so fast that you
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.
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
110 MODULE EXPORTS
111 This module does not export any symbols.
70 112
71EVENT LOOPS 113EVENT LOOPS
72 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"
73 that can handle everything including signals and child watchers, and any 115 that can handle everything including signals and child watchers, and any
74 number of "dynamic event loops" that can use different backends (with 116 number of "dynamic event loops" that can use different backends (with
… …
81 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
82 modules (e.g. AnyEvent or Coro) and most portable event loop. 124 modules (e.g. AnyEvent or Coro) and most portable event loop.
83 125
84 For specific programs you can create additional event loops dynamically. 126 For specific programs you can create additional event loops dynamically.
85 127
86 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
87 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
88 *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
89 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
90 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
91 that. 133 that.
92 134
93 $loop = new EV::loop [$flags] 135 $loop = new EV::Loop [$flags]
94 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
95 the "ev_loop_new ()" function description in the libev documentation 137 the "ev_loop_new ()" function description in the libev documentation
96 (<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
97 ONS>) for more info. 139 ONS>, or locally-installed as EV::libev manpage) for more info.
98 140
99 The loop will automatically be destroyed when it is no longer 141 The loop will automatically be destroyed when it is no longer
100 referenced by any watcher and the loop object goes out of scope. 142 referenced by any watcher and the loop object goes out of scope.
101 143
102 Using "EV::FLAG_FORKCHECK" is recommended, as only the default event 144 If you are not embedding the loop, then Using "EV::FLAG_FORKCHECK"
103 loop is protected by this module. 145 is recommended, as only the default event loop is protected by this
146 module. If you *are* embedding this loop in the default loop, this
147 is not necessary, as "EV::embed" automatically does the right thing
148 on fork.
104 149
105 $loop->loop_fork 150 $loop->loop_fork
106 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
107 continuing the event loop. An alternative is to use 152 continuing the event loop. An alternative is to use
108 "EV::FLAG_FORKCHECK" which calls this function automatically, at 153 "EV::FLAG_FORKCHECK" which calls this function automatically, at
109 some performance loss (refer to the libev documentation). 154 some performance loss (refer to the libev documentation).
110 155
111 $loop->loop_verify 156 $loop->verify
112 Calls "ev_verify" to make internal consistency checks (for debugging 157 Calls "ev_verify" to make internal consistency checks (for debugging
113 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
114 corrupted. 159 corrupted.
115 160
116 $loop = EV::default_loop [$flags] 161 $loop = EV::default_loop [$flags]
… …
143 Returns the current time in (fractional) seconds since the epoch. 188 Returns the current time in (fractional) seconds since the epoch.
144 189
145 $time = EV::now 190 $time = EV::now
146 $time = $loop->now 191 $time = $loop->now
147 Returns the time the last event loop iteration has been started. 192 Returns the time the last event loop iteration has been started.
148 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
149 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").
150 232
151 $backend = EV::backend 233 $backend = EV::backend
152 $backend = $loop->backend 234 $backend = $loop->backend
153 Returns an integer describing the backend used by libev 235 Returns an integer describing the backend used by libev
154 (EV::METHOD_SELECT or EV::METHOD_EPOLL). 236 (EV::BACKEND_SELECT or EV::BACKEND_EPOLL).
155 237
156 EV::loop [$flags] 238 $active = EV::run [$flags]
157 $loop->loop ([$flags]) 239 $active = $loop->run ([$flags])
158 Begin checking for events and calling callbacks. It returns when a 240 Begin checking for events and calling callbacks. It returns when a
159 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".
160 246
161 The $flags argument can be one of the following: 247 The $flags argument can be one of the following:
162 248
163 0 as above 249 0 as above
164 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 250 EV::RUN_ONCE block at most once (wait, but do not loop)
165 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 251 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
166 252
167 EV::unloop [$how] 253 EV::break [$how]
168 $loop->unloop ([$how]) 254 $loop->break ([$how])
169 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
170 makes the innermost call to EV::loop return. 256 the innermost call to EV::run return.
171 257
172 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
173 EV::loop will return as fast as possible. 259 will return as fast as possible.
174 260
175 $count = EV::loop_count 261 When called with an argument of EV::BREAK_CANCEL, any pending break
176 $count = $loop->loop_count 262 will be cancelled.
263
264 $count = EV::iteration
265 $count = $loop->iteration
177 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.
178 Sometiems useful as a generation counter. 267 Sometimes useful as a generation counter.
179 268
180 EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 269 EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
181 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 270 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
182 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
183 one-shot event without the need for managing a watcher object. 272 one-shot event without the need for managing a watcher object.
… …
187 "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
188 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
189 "undef" for $fh_or_undef and 0 for $events). 278 "undef" for $fh_or_undef and 0 for $events).
190 279
191 If timeout is "undef" or negative, then there will be no timeout. 280 If timeout is "undef" or negative, then there will be no timeout.
192 Otherwise a EV::timer with this value will be started. 281 Otherwise an "EV::timer" with this value will be started.
193 282
194 When an error occurs or either the timeout or I/O watcher triggers, 283 When an error occurs or either the timeout or I/O watcher triggers,
195 then the callback will be called with the received event set (in 284 then the callback will be called with the received event set (in
196 general you can expect it to be a combination of "EV::ERROR", 285 general you can expect it to be a combination of "EV::ERROR",
197 "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). 286 "EV::READ", "EV::WRITE" and "EV::TIMER").
198 287
199 EV::once doesn't return anything: the watchers stay active till 288 EV::once doesn't return anything: the watchers stay active till
200 either of them triggers, then they will be stopped and freed, and 289 either of them triggers, then they will be stopped and freed, and
201 the callback invoked. 290 the callback invoked.
202 291
203 EV::feed_fd_event ($fd, $revents) 292 EV::feed_fd_event $fd, $revents
204 $loop->feed_fd_event ($fd, $revents) 293 $loop->feed_fd_event ($fd, $revents)
205 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
206 call as if the readyness notifications specified by $revents (a 295 call as if the readyness notifications specified by $revents (a
207 combination of "EV::READ" and "EV::WRITE") happened on the file 296 combination of "EV::READ" and "EV::WRITE") happened on the file
208 descriptor $fd. 297 descriptor $fd.
209 298
210 EV::feed_signal_event ($signal) 299 EV::feed_signal_event $signal
211 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
212 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.
213 307
214 EV::set_io_collect_interval $time 308 EV::set_io_collect_interval $time
215 $loop->set_io_collect_interval ($time) 309 $loop->set_io_collect_interval ($time)
216 EV::set_timeout_collect_interval $time 310 EV::set_timeout_collect_interval $time
217 $loop->set_timeout_collect_interval ($time) 311 $loop->set_timeout_collect_interval ($time)
218 These advanced functions set the minimum block interval when polling 312 These advanced functions set the minimum block interval when polling
219 for I/O events and the minimum wait interval for timer events. See 313 for I/O events and the minimum wait interval for timer events. See
220 the libev documentation at 314 the libev documentation at
221 <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
222 ROLLING_THE_EVENT_LOOP> for a more detailed discussion. 316 ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more
317 detailed discussion.
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.
223 326
224WATCHER OBJECTS 327WATCHER OBJECTS
225 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
226 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,
227 you would create an EV::io watcher for that: 330 you would create an EV::io watcher for that:
… …
236 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
237 received events. 340 received events.
238 341
239 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
240 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
241 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,
242 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
243 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).
244 (which uses EV::TIMEOUT).
245 347
246 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
247 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
248 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.
249 351
… …
312 If the watcher is pending, this function clears its pending status 414 If the watcher is pending, this function clears its pending status
313 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
314 the watcher isn't pending it does nothing and returns 0. 416 the watcher isn't pending it does nothing and returns 0.
315 417
316 $previous_state = $w->keepalive ($bool) 418 $previous_state = $w->keepalive ($bool)
317 Normally, "EV::loop" will return when there are no active watchers 419 Normally, "EV::run" will return when there are no active watchers
318 (which is a "deadlock" because no progress can be made anymore). 420 (which is a "deadlock" because no progress can be made anymore).
319 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
320 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
321 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
322 for their task :). 424 for their task :).
323 425
324 Sometimes, however, this gets in your way, for example when the 426 Sometimes, however, this gets in your way, for example when the
325 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
326 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
327 module written by somebody else even). Then you might want any 429 module written by somebody else even). Then you might want any
328 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
329 "EV::loop" from returning just because you happen to have this 431 "EV::run" from returning just because you happen to have this
330 long-running UDP port watcher. 432 long-running UDP port watcher.
331 433
332 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
333 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
334 returning. 436 returning.
335 437
336 The initial value for keepalive is true (enabled), and you cna 438 The initial value for keepalive is true (enabled), and you can
337 change it any time. 439 change it any time.
338 440
339 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
340 the event loop from running just because of that watcher. 442 the event loop from running just because of that watcher.
341 443
… …
380 TIMER WATCHERS - relative and optionally repeating timeouts 482 TIMER WATCHERS - relative and optionally repeating timeouts
381 $w = EV::timer $after, $repeat, $callback 483 $w = EV::timer $after, $repeat, $callback
382 $w = EV::timer_ns $after, $repeat, $callback 484 $w = EV::timer_ns $after, $repeat, $callback
383 $w = $loop->timer ($after, $repeat, $callback) 485 $w = $loop->timer ($after, $repeat, $callback)
384 $w = $loop->timer_ns ($after, $repeat, $callback) 486 $w = $loop->timer_ns ($after, $repeat, $callback)
385 Calls the callback after $after seconds (which may be fractional). 487 Calls the callback after $after seconds (which may be fractional or
386 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
387 $repeat value as $after) after the callback returns. 489 the $repeat value as $after) after the callback returns.
388 490
389 This means that the callback would be called roughly after $after 491 This means that the callback would be called roughly after $after
390 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
391 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
392 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
… …
399 the same time. 501 the same time.
400 502
401 The "timer_ns" variant doesn't start (activate) the newly created 503 The "timer_ns" variant doesn't start (activate) the newly created
402 watcher. 504 watcher.
403 505
404 $w->set ($after, $repeat) 506 $w->set ($after, $repeat = 0)
405 Reconfigures the watcher, see the constructor above for details. Can 507 Reconfigures the watcher, see the constructor above for details. Can
406 be called at any time. 508 be called at any time.
407 509
408 $w->again 510 $w->again
511 $w->again ($repeat)
409 Similar to the "start" method, but has special semantics for 512 Similar to the "start" method, but has special semantics for
410 repeating timers: 513 repeating timers:
411 514
412 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.
413 516
… …
421 524
422 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
423 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
424 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"
425 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.
426 542
427 PERIODIC WATCHERS - to cron or not to cron? 543 PERIODIC WATCHERS - to cron or not to cron?
428 $w = EV::periodic $at, $interval, $reschedule_cb, $callback 544 $w = EV::periodic $at, $interval, $reschedule_cb, $callback
429 $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 545 $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
430 $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback) 546 $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
… …
447 system time reaches or surpasses this time. 563 system time reaches or surpasses this time.
448 564
449 * repeating interval timer ($interval > 0, $reschedule_cb = 0) 565 * repeating interval timer ($interval > 0, $reschedule_cb = 0)
450 566
451 In this mode the watcher will always be scheduled to time out at 567 In this mode the watcher will always be scheduled to time out at
452 the next "$at + N * $interval" time (for some integer N) and 568 the next "$at + N * $interval" time (for the lowest integer N)
453 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.
454 571
455 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
456 to system time: 573 to system time:
457 574
458 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; 575 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
459 576
460 That doesn't mean there will always be 3600 seconds in between 577 That doesn't mean there will always be 3600 seconds in between
461 triggers, but only that the the clalback will be called when the 578 triggers, but only that the the callback will be called when the
462 system time shows a full hour (UTC). 579 system time shows a full hour (UTC).
463 580
464 Another way to think about it (for the mathematically inclined) 581 Another way to think about it (for the mathematically inclined)
465 is that EV::periodic will try to run the callback in this mode 582 is that EV::periodic will try to run the callback in this mode
466 at the next possible time where "$time = $at (mod $interval)", 583 at the next possible time where "$time = $at (mod $interval)",
… …
474 first, and the current time as second argument. 591 first, and the current time as second argument.
475 592
476 *This callback MUST NOT stop or destroy this or any other 593 *This callback MUST NOT stop or destroy this or any other
477 periodic watcher, ever, and MUST NOT call any event loop 594 periodic watcher, ever, and MUST NOT call any event loop
478 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
479 stop it afterwards. You may create and start a "EV::prepare" 596 stop it afterwards. You may create and start an "EV::prepare"
480 watcher for this task. 597 watcher for this task.
481 598
482 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
483 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
484 to to the second argument). It will usually be called just 601 to to the second argument). It will usually be called just
485 before the callback will be triggered, but might be called at 602 before the callback will be triggered, but might be called at
486 other times, too. 603 other times, too.
487 604
488 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
489 that triggers on each midnight, local time (actually 24 hours 606 that triggers on each midnight, local time (actually one day
490 after the last midnight, to keep the example simple. If you know 607 after the last midnight, to keep the example simple):
491 a way to do it correctly in about the same space (without
492 requiring elaborate modules), drop me a note :):
493 608
494 my $daily = EV::periodic 0, 0, sub { 609 my $daily = EV::periodic 0, 0, sub {
495 my ($w, $now) = @_; 610 my ($w, $now) = @_;
496 611
497 use Time::Local (); 612 use Time::Local ();
498 my (undef, undef, undef, $d, $m, $y) = localtime $now; 613 my (undef, undef, undef, $d, $m, $y) = localtime $now;
499 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y 614 Time::Local::timelocal_nocheck 0, 0, 0, $d + 1, $m, $y
500 }, sub { 615 }, sub {
501 print "it's midnight or likely shortly after, now\n"; 616 print "it's midnight or likely shortly after, now\n";
502 }; 617 };
503 618
504 The "periodic_ns" variant doesn't start (activate) the newly created 619 The "periodic_ns" variant doesn't start (activate) the newly created
… …
512 Simply stops and starts the watcher again. 627 Simply stops and starts the watcher again.
513 628
514 $time = $w->at 629 $time = $w->at
515 Return the time that the watcher is expected to trigger next. 630 Return the time that the watcher is expected to trigger next.
516 631
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
517 SIGNAL WATCHERS - signal me when a signal gets signalled! 647 SIGNAL WATCHERS - signal me when a signal gets signalled!
518 $w = EV::signal $signal, $callback 648 $w = EV::signal $signal, $callback
519 $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)
520 Call the callback when $signal is received (the signal can be 652 Call the callback when $signal is received (the signal can be
521 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.
522 658
523 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
524 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
525 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
526 when you add/remove callbacks to %SIG, so watch out. 662 when you add/remove callbacks to %SIG, so watch out.
… …
700 $w = $loop->check_ns ($callback) 836 $w = $loop->check_ns ($callback)
701 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
702 has gathered events), but before any other callbacks have been 838 has gathered events), but before any other callbacks have been
703 invoked. 839 invoked.
704 840
705 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
706 mainloop: You register a prepare callback and in there, you create 842 mainloop: You register a prepare callback and in there, you create
707 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
708 real-world example of integrating Net::SNMP (with some details left 844 real-world example of integrating Net::SNMP (with some details left
709 out): 845 out):
710 846
… …
741 # make the dispatcher handle any new stuff 877 # make the dispatcher handle any new stuff
742 ... not shown 878 ... not shown
743 }; 879 };
744 880
745 The callbacks of the created watchers will not be called as the 881 The callbacks of the created watchers will not be called as the
746 watchers are destroyed before this cna happen (remember EV::check 882 watchers are destroyed before this can happen (remember EV::check
747 gets called first). 883 gets called first).
748 884
749 The "check_ns" variant doesn't start (activate) the newly created 885 The "check_ns" variant doesn't start (activate) the newly created
750 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.
751 896
752 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
753 Fork watchers are called when a "fork ()" was detected. The invocation 898 Fork watchers are called when a "fork ()" was detected. The invocation
754 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
755 are being called, and only in the child after the fork. 900 are being called, and only in the child after the fork.
… …
770 embedded loop, other types of watchers might be handled in a delayed or 915 embedded loop, other types of watchers might be handled in a delayed or
771 incorrect fashion and must not be used). 916 incorrect fashion and must not be used).
772 917
773 See the libev documentation at 918 See the libev documentation at
774 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code 919 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code
775 _when_one_backend_> for more details. 920 _when_one_backend_> (locally installed as EV::libev) for more details.
776 921
777 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
778 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:
779 924
780 my $socket_loop; 925 my $socket_loop;
781 926
782 # check wether we use SELECT or POLL _and_ KQUEUE is supported 927 # check wether we use SELECT or POLL _and_ KQUEUE is supported
783 if ( 928 if (
784 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 929 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
785 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 930 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
786 ) { 931 ) {
787 # use kqueue for sockets 932 # use kqueue for sockets
788 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 933 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
789 } 934 }
790 935
791 # use the default loop otherwise 936 # use the default loop otherwise
792 $socket_loop ||= EV::default_loop; 937 $socket_loop ||= EV::default_loop;
793 938
794 $w = EV::embed $otherloop, $callback 939 $w = EV::embed $otherloop[, $callback]
795 $w = EV::embed_ns $otherloop, $callback 940 $w = EV::embed_ns $otherloop[, $callback]
796 $w = $loop->embed ($otherloop, $callback) 941 $w = $loop->embed ($otherloop[, $callback])
797 $w = $loop->embed_ns ($otherloop, $callback) 942 $w = $loop->embed_ns ($otherloop[, $callback])
798 Call the callback when the embedded event loop ($otherloop) has any 943 Call the callback when the embedded event loop ($otherloop) has any
799 I/O activity. The $callback should alwas be specified as "undef" in 944 I/O activity. The $callback is optional: if it is missing, then the
800 this version of EV, which means the embedded event loop will be 945 embedded event loop will be managed automatically (which is
801 managed automatically. 946 recommended), otherwise you have to invoke "sweep" yourself.
802 947
803 The "embed_ns" variant doesn't start (activate) the newly created 948 The "embed_ns" variant doesn't start (activate) the newly created
804 watcher. 949 watcher.
805 950
806 ASYNC WATCHERS - how to wake up another event loop 951 ASYNC WATCHERS - how to wake up another event loop
807 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,
808 as perl neither supports threads nor direct access to signal handlers or 953 as perl neither supports threads running in parallel nor direct access
809 other contexts where they could be of value. 954 to signal handlers or other contexts where they could be of value.
810 955
811 It is, however, possible to use them from the XS level. 956 It is, however, possible to use them from the XS level.
812 957
813 Please see the libev documentation for further details. 958 Please see the libev documentation for further details.
814 959
815 $w = EV::async $callback 960 $w = EV::async $callback
816 $w = EV::async_ns $callback 961 $w = EV::async_ns $callback
962 $w = $loop->async ($callback)
963 $w = $loop->async_ns ($callback)
817 $w->send 964 $w->send
818 $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.
819 970
820PERL SIGNALS 971PERL SIGNALS
821 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
822 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
823 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
… …
833 my $async_check = EV::check sub { }; 984 my $async_check = EV::check sub { };
834 985
835 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
836 pending signals, and also ensures (slightly) slower overall operation. 987 pending signals, and also ensures (slightly) slower overall operation.
837 988
838THREADS 989ITHREADS
839 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
840 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
841 work on thread support for it. 992 Coro are fully supported (and enhanced support is available via
993 Coro::EV).
842 994
843FORK 995FORK
844 Most of the "improved" event delivering mechanisms of modern operating 996 Most of the "improved" event delivering mechanisms of modern operating
845 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
846 not supported and usually destructive). Libev makes it possible to work 998 not supported and usually destructive). Libev makes it possible to work
… …
856 1008
857 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
858 course. 1010 course.
859 1011
860SEE ALSO 1012SEE ALSO
861 EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event 1013 EV::MakeMaker - MakeMaker interface to XS API, EV::ADNS (asynchronous
862 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
863 with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop 1015 Glib into EV), Coro::EV (efficient thread integration), Net::SNMP::EV
864 agnostic and portable event driven programming. 1016 (asynchronous SNMP), AnyEvent for event-loop agnostic and portable event
1017 driven programming.
865 1018
866AUTHOR 1019AUTHOR
867 Marc Lehmann <schmorp@schmorp.de> 1020 Marc Lehmann <schmorp@schmorp.de>
868 http://home.schmorp.de/ 1021 http://home.schmorp.de/
869 1022

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