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Revision 1.16 by root, Fri Dec 7 18:11:23 2007 UTC vs.
Revision 1.20 by root, Sat Dec 22 12:05:42 2007 UTC

59 libev itself (<http://cvs.schmorp.de/libev/ev.html>) for more subtle 59 libev itself (<http://cvs.schmorp.de/libev/ev.html>) for more subtle
60 details on watcher semantics or some discussion on the available 60 details on watcher semantics or some discussion on the available
61 backends, or how to force a specific backend with "LIBEV_FLAGS", or just 61 backends, or how to force a specific backend with "LIBEV_FLAGS", or just
62 about in any case because it has much more detailed information. 62 about in any case because it has much more detailed information.
63 63
64EVENT LOOPS
65 EV supports multiple event loops: There is a single "default event loop"
66 that can handle everything including signals and child watchers, and any
67 number of "dynamic event loops" that can use different backends (with
68 various limitations), but no child and signal watchers.
69
70 You do not have to do anything to create the default event loop: When
71 the module is loaded a suitable backend is selected on the premise of
72 selecting a working backend (which for example rules out kqueue on most
73 BSDs). Modules should, unless they have "special needs" always use the
74 default loop as this is fastest (perl-wise), best supported by other
75 modules (e.g. AnyEvent or Coro) and most portable event loop.
76
77 For specific programs you cna create additional event loops dynamically.
78
79 $loop = new EV::loop [$flags]
80 Create a new event loop as per the specified flags. Please refer to
81 the "ev_loop_new ()" function description in the libev documentation
82 (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI
83 ONS>) for more info.
84
85 The loop will automatically be destroyed when it is no longer
86 referenced by any watcher and the loop object goes out of scope.
87
88 Using "EV::FLAG_FORKCHECK" is recommended, as only the default event
89 loop is protected by this module.
90
91 $loop->loop_fork
92 Must be called after a fork in the child, before entering or
93 continuing the event loop. An alternative is to use
94 "EV::FLAG_FORKCHECK" which calls this fucntion automatically, at
95 some performance loss (refer to the libev documentation).
96
64BASIC INTERFACE 97BASIC INTERFACE
65 $EV::DIED 98 $EV::DIED
66 Must contain a reference to a function that is called when a 99 Must contain a reference to a function that is called when a
67 callback throws an exception (with $@ containing thr error). The 100 callback throws an exception (with $@ containing the error). The
68 default prints an informative message and continues. 101 default prints an informative message and continues.
69 102
70 If this callback throws an exception it will be silently ignored. 103 If this callback throws an exception it will be silently ignored.
71 104
72 $time = EV::time 105 $time = EV::time
73 Returns the current time in (fractional) seconds since the epoch. 106 Returns the current time in (fractional) seconds since the epoch.
74 107
75 $time = EV::now 108 $time = EV::now
109 $time = $loop->now
76 Returns the time the last event loop iteration has been started. 110 Returns the time the last event loop iteration has been started.
77 This is the time that (relative) timers are based on, and refering 111 This is the time that (relative) timers are based on, and refering
78 to it is usually faster then calling EV::time. 112 to it is usually faster then calling EV::time.
79 113
80 $method = EV::method 114 $backend = EV::backend
115 $backend = $loop->backend
81 Returns an integer describing the backend used by libev 116 Returns an integer describing the backend used by libev
82 (EV::METHOD_SELECT or EV::METHOD_EPOLL). 117 (EV::METHOD_SELECT or EV::METHOD_EPOLL).
83 118
84 EV::loop [$flags] 119 EV::loop [$flags]
120 $loop->loop ([$flags])
85 Begin checking for events and calling callbacks. It returns when a 121 Begin checking for events and calling callbacks. It returns when a
86 callback calls EV::unloop. 122 callback calls EV::unloop.
87 123
88 The $flags argument can be one of the following: 124 The $flags argument can be one of the following:
89 125
90 0 as above 126 0 as above
91 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 127 EV::LOOP_ONESHOT block at most once (wait, but do not loop)
92 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 128 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
93 129
94 EV::unloop [$how] 130 EV::unloop [$how]
131 $loop->unloop ([$how])
95 When called with no arguments or an argument of EV::UNLOOP_ONE, 132 When called with no arguments or an argument of EV::UNLOOP_ONE,
96 makes the innermost call to EV::loop return. 133 makes the innermost call to EV::loop return.
97 134
98 When called with an argument of EV::UNLOOP_ALL, all calls to 135 When called with an argument of EV::UNLOOP_ALL, all calls to
99 EV::loop will return as fast as possible. 136 EV::loop will return as fast as possible.
100 137
101 $count = EV::loop_count 138 $count = EV::loop_count
139 $count = $loop->loop_count
102 Return the number of times the event loop has polled for new events. 140 Return the number of times the event loop has polled for new events.
103 Sometiems useful as a generation counter. 141 Sometiems useful as a generation counter.
104 142
105 EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 143 EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
144 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
106 This function rolls together an I/O and a timer watcher for a single 145 This function rolls together an I/O and a timer watcher for a single
107 one-shot event without the need for managing a watcher object. 146 one-shot event without the need for managing a watcher object.
108 147
109 If $fh_or_undef is a filehandle or file descriptor, then $events 148 If $fh_or_undef is a filehandle or file descriptor, then $events
110 must be a bitset containing either "EV::READ", "EV::WRITE" or 149 must be a bitset containing either "EV::READ", "EV::WRITE" or
115 If timeout is "undef" or negative, then there will be no timeout. 154 If timeout is "undef" or negative, then there will be no timeout.
116 Otherwise a EV::timer with this value will be started. 155 Otherwise a EV::timer with this value will be started.
117 156
118 When an error occurs or either the timeout or I/O watcher triggers, 157 When an error occurs or either the timeout or I/O watcher triggers,
119 then the callback will be called with the received event set (in 158 then the callback will be called with the received event set (in
120 general you can expect it to be a combination of "EV:ERROR", 159 general you can expect it to be a combination of "EV::ERROR",
121 "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). 160 "EV::READ", "EV::WRITE" and "EV::TIMEOUT").
122 161
123 EV::once doesn't return anything: the watchers stay active till 162 EV::once doesn't return anything: the watchers stay active till
124 either of them triggers, then they will be stopped and freed, and 163 either of them triggers, then they will be stopped and freed, and
125 the callback invoked. 164 the callback invoked.
126 165
166 EV::feed_fd_event ($fd, $revents)
167 $loop->feed_fd_event ($fd, $revents)
168 Feed an event on a file descriptor into EV. EV will react to this
169 call as if the readyness notifications specified by $revents (a
170 combination of "EV::READ" and "EV::WRITE") happened on the file
171 descriptor $fd.
172
173 EV::feed_signal_event ($signal)
174 Feed a signal event into EV. EV will react to this call as if the
175 signal specified by $signal had occured.
176
127 WATCHER OBJECTS 177WATCHER OBJECTS
128 A watcher is an object that gets created to record your interest in some 178 A watcher is an object that gets created to record your interest in some
129 event. For instance, if you want to wait for STDIN to become readable, 179 event. For instance, if you want to wait for STDIN to become readable,
130 you would create an EV::io watcher for that: 180 you would create an EV::io watcher for that:
131 181
132 my $watcher = EV::io *STDIN, EV::READ, sub { 182 my $watcher = EV::io *STDIN, EV::READ, sub {
133 my ($watcher, $revents) = @_; 183 my ($watcher, $revents) = @_;
134 warn "yeah, STDIN should not be readable without blocking!\n" 184 warn "yeah, STDIN should now be readable without blocking!\n"
135 }; 185 };
136 186
137 All watchers can be active (waiting for events) or inactive (paused). 187 All watchers can be active (waiting for events) or inactive (paused).
138 Only active watchers will have their callbacks invoked. All callbacks 188 Only active watchers will have their callbacks invoked. All callbacks
139 will be called with at least two arguments: the watcher and a bitmask of 189 will be called with at least two arguments: the watcher and a bitmask of
202 The default priority of any newly-created watcher is 0. 252 The default priority of any newly-created watcher is 0.
203 253
204 Note that the priority semantics have not yet been fleshed out and 254 Note that the priority semantics have not yet been fleshed out and
205 are subject to almost certain change. 255 are subject to almost certain change.
206 256
207 $w->trigger ($revents) 257 $w->invoke ($revents)
208 Call the callback *now* with the given event mask. 258 Call the callback *now* with the given event mask.
259
260 $w->feed_event ($revents)
261 Feed some events on this watcher into EV. EV will react to this call
262 as if the watcher had received the given $revents mask.
263
264 $revents = $w->clear_pending
265 If the watcher is pending, this function clears its pending status
266 and returns its $revents bitset (as if its callback was invoked). If
267 the watcher isn't pending it does nothing and returns 0.
209 268
210 $previous_state = $w->keepalive ($bool) 269 $previous_state = $w->keepalive ($bool)
211 Normally, "EV::loop" will return when there are no active watchers 270 Normally, "EV::loop" will return when there are no active watchers
212 (which is a "deadlock" because no progress can be made anymore). 271 (which is a "deadlock" because no progress can be made anymore).
213 This is convinient because it allows you to start your watchers (and 272 This is convinient because it allows you to start your watchers (and
214 your jobs), call "EV::loop" once and when it returns you know that 273 your jobs), call "EV::loop" once and when it returns you know that
215 all your jobs are finished (or they forgot to register some watchers 274 all your jobs are finished (or they forgot to register some watchers
216 for their task :). 275 for their task :).
217 276
218 Sometimes, however, this gets in your way, for example when you the 277 Sometimes, however, this gets in your way, for example when the
219 module that calls "EV::loop" (usually the main program) is not the 278 module that calls "EV::loop" (usually the main program) is not the
220 same module as a long-living watcher (for example a DNS client 279 same module as a long-living watcher (for example a DNS client
221 module written by somebody else even). Then you might want any 280 module written by somebody else even). Then you might want any
222 outstanding requests to be handled, but you would not want to keep 281 outstanding requests to be handled, but you would not want to keep
223 "EV::loop" from returning just because you happen to have this 282 "EV::loop" from returning just because you happen to have this
233 Example: Register an I/O watcher for some UDP socket but do not keep 292 Example: Register an I/O watcher for some UDP socket but do not keep
234 the event loop from running just because of that watcher. 293 the event loop from running just because of that watcher.
235 294
236 my $udp_socket = ... 295 my $udp_socket = ...
237 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 296 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
238 $udp_watcher->keepalive (0); 297 $1000udp_watcher->keepalive (0);
239 298
299 $loop = $w->loop
300 Return the loop that this watcher is attached to.
301
240 WATCHER TYPES 302WATCHER TYPES
241 Each of the following subsections describes a single watcher type. 303 Each of the following subsections describes a single watcher type.
242 304
243 I/O WATCHERS - is this file descriptor readable or writable? 305 I/O WATCHERS - is this file descriptor readable or writable?
244 $w = EV::io $fileno_or_fh, $eventmask, $callback 306 $w = EV::io $fileno_or_fh, $eventmask, $callback
245 $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 307 $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
308 $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
309 $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
246 As long as the returned watcher object is alive, call the $callback 310 As long as the returned watcher object is alive, call the $callback
247 when at least one of events specified in $eventmask occurs. 311 when at least one of events specified in $eventmask occurs.
248 312
249 The $eventmask can be one or more of these constants ORed together: 313 The $eventmask can be one or more of these constants ORed together:
250 314
267 Returns the previously set event mask and optionally set a new one. 331 Returns the previously set event mask and optionally set a new one.
268 332
269 TIMER WATCHERS - relative and optionally repeating timeouts 333 TIMER WATCHERS - relative and optionally repeating timeouts
270 $w = EV::timer $after, $repeat, $callback 334 $w = EV::timer $after, $repeat, $callback
271 $w = EV::timer_ns $after, $repeat, $callback 335 $w = EV::timer_ns $after, $repeat, $callback
336 $w = $loop->timer ($after, $repeat, $callback)
337 $w = $loop->timer_ns ($after, $repeat, $callback)
272 Calls the callback after $after seconds (which may be fractional). 338 Calls the callback after $after seconds (which may be fractional).
273 If $repeat is non-zero, the timer will be restarted (with the 339 If $repeat is non-zero, the timer will be restarted (with the
274 $repeat value as $after) after the callback returns. 340 $repeat value as $after) after the callback returns.
275 341
276 This means that the callback would be called roughly after $after 342 This means that the callback would be called roughly after $after
312 method on the timeout. 378 method on the timeout.
313 379
314 PERIODIC WATCHERS - to cron or not to cron? 380 PERIODIC WATCHERS - to cron or not to cron?
315 $w = EV::periodic $at, $interval, $reschedule_cb, $callback 381 $w = EV::periodic $at, $interval, $reschedule_cb, $callback
316 $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 382 $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
383 $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
384 $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
317 Similar to EV::timer, but is not based on relative timeouts but on 385 Similar to EV::timer, but is not based on relative timeouts but on
318 absolute times. Apart from creating "simple" timers that trigger 386 absolute times. Apart from creating "simple" timers that trigger
319 "at" the specified time, it can also be used for non-drifting 387 "at" the specified time, it can also be used for non-drifting
320 absolute timers and more complex, cron-like, setups that are not 388 absolute timers and more complex, cron-like, setups that are not
321 adversely affected by time jumps (i.e. when the system clock is 389 adversely affected by time jumps (i.e. when the system clock is
389 be called at any time. 457 be called at any time.
390 458
391 $w->again 459 $w->again
392 Simply stops and starts the watcher again. 460 Simply stops and starts the watcher again.
393 461
462 $time = $w->at
463 Return the time that the watcher is expected to trigger next.
464
394 SIGNAL WATCHERS - signal me when a signal gets signalled! 465 SIGNAL WATCHERS - signal me when a signal gets signalled!
395 $w = EV::signal $signal, $callback 466 $w = EV::signal $signal, $callback
396 $w = EV::signal_ns $signal, $callback 467 $w = EV::signal_ns $signal, $callback
397 Call the callback when $signal is received (the signal can be 468 Call the callback when $signal is received (the signal can be
398 specified by number or by name, just as with "kill" or %SIG). 469 specified by number or by name, just as with "kill" or %SIG).
417 optionally set a new one. 488 optionally set a new one.
418 489
419 CHILD WATCHERS - watch out for process status changes 490 CHILD WATCHERS - watch out for process status changes
420 $w = EV::child $pid, $callback 491 $w = EV::child $pid, $callback
421 $w = EV::child_ns $pid, $callback 492 $w = EV::child_ns $pid, $callback
493 $w = $loop->child ($pid, $callback)
494 $w = $loop->child_ns ($pid, $callback)
422 Call the callback when a status change for pid $pid (or any pid if 495 Call the callback when a status change for pid $pid (or any pid if
423 $pid is 0) has been received. More precisely: when the process 496 $pid is 0) has been received. More precisely: when the process
424 receives a "SIGCHLD", EV will fetch the outstanding exit/wait status 497 receives a "SIGCHLD", EV will fetch the outstanding exit/wait status
425 for all changed/zombie children and call the callback. 498 for all changed/zombie children and call the callback.
426 499
456 a watcher for all pids). 529 a watcher for all pids).
457 530
458 STAT WATCHERS - did the file attributes just change? 531 STAT WATCHERS - did the file attributes just change?
459 $w = EV::stat $path, $interval, $callback 532 $w = EV::stat $path, $interval, $callback
460 $w = EV::stat_ns $path, $interval, $callback 533 $w = EV::stat_ns $path, $interval, $callback
534 $w = $loop->stat ($path, $interval, $callback)
535 $w = $loop->stat_ns ($path, $interval, $callback)
461 Call the callback when a file status change has been detected on 536 Call the callback when a file status change has been detected on
462 $path. The $path does not need to exist, changing from "path exists" 537 $path. The $path does not need to exist, changing from "path exists"
463 to "path does not exist" is a status change like any other. 538 to "path does not exist" is a status change like any other.
464 539
465 The $interval is a recommended polling interval for systems where 540 The $interval is a recommended polling interval for systems where
525 Can be used to query the actual interval used. 600 Can be used to query the actual interval used.
526 601
527 IDLE WATCHERS - when you've got nothing better to do... 602 IDLE WATCHERS - when you've got nothing better to do...
528 $w = EV::idle $callback 603 $w = EV::idle $callback
529 $w = EV::idle_ns $callback 604 $w = EV::idle_ns $callback
605 $w = $loop->idle ($callback)
606 $w = $loop->idle_ns ($callback)
530 Call the callback when there are no other pending watchers of the 607 Call the callback when there are no other pending watchers of the
531 same or higher priority (excluding check, prepare and other idle 608 same or higher priority (excluding check, prepare and other idle
532 watchers of the same or lower priority, of course). They are called 609 watchers of the same or lower priority, of course). They are called
533 idle watchers because when the watcher is the highest priority 610 idle watchers because when the watcher is the highest priority
534 pending event in the process, the process is considered to be idle 611 pending event in the process, the process is considered to be idle
550 watcher. 627 watcher.
551 628
552 PREPARE WATCHERS - customise your event loop! 629 PREPARE WATCHERS - customise your event loop!
553 $w = EV::prepare $callback 630 $w = EV::prepare $callback
554 $w = EV::prepare_ns $callback 631 $w = EV::prepare_ns $callback
632 $w = $loop->prepare ($callback)
633 $w = $loop->prepare_ns ($callback)
555 Call the callback just before the process would block. You can still 634 Call the callback just before the process would block. You can still
556 create/modify any watchers at this point. 635 create/modify any watchers at this point.
557 636
558 See the EV::check watcher, below, for explanations and an example. 637 See the EV::check watcher, below, for explanations and an example.
559 638
561 watcher. 640 watcher.
562 641
563 CHECK WATCHERS - customise your event loop even more! 642 CHECK WATCHERS - customise your event loop even more!
564 $w = EV::check $callback 643 $w = EV::check $callback
565 $w = EV::check_ns $callback 644 $w = EV::check_ns $callback
645 $w = $loop->check ($callback)
646 $w = $loop->check_ns ($callback)
566 Call the callback just after the process wakes up again (after it 647 Call the callback just after the process wakes up again (after it
567 has gathered events), but before any other callbacks have been 648 has gathered events), but before any other callbacks have been
568 invoked. 649 invoked.
569 650
570 This is used to integrate other event-based software into the EV 651 This is used to integrate other event-based software into the EV
619 is done before the event loop blocks next and before "check" watchers 700 is done before the event loop blocks next and before "check" watchers
620 are being called, and only in the child after the fork. 701 are being called, and only in the child after the fork.
621 702
622 $w = EV::fork $callback 703 $w = EV::fork $callback
623 $w = EV::fork_ns $callback 704 $w = EV::fork_ns $callback
705 $w = $loop->fork ($callback)
706 $w = $loop->fork_ns ($callback)
624 Call the callback before the event loop is resumed in the child 707 Call the callback before the event loop is resumed in the child
625 process after a fork. 708 process after a fork.
626 709
627 The "fork_ns" variant doesn't start (activate) the newly created 710 The "fork_ns" variant doesn't start (activate) the newly created
628 watcher. 711 watcher.
640 to be called on every event loop iteration by installing a "EV::check" 723 to be called on every event loop iteration by installing a "EV::check"
641 watcher: 724 watcher:
642 725
643 my $async_check = EV::check sub { }; 726 my $async_check = EV::check sub { };
644 727
645 This ensures that perl shortly gets into control for a short time, and 728 This ensures that perl gets into control for a short time to handle any
646 also ensures slower overall operation. 729 pending signals, and also ensures (slightly) slower overall operation.
647 730
648THREADS 731THREADS
649 Threads are not supported by this module in any way. Perl pseudo-threads 732 Threads are not supported by this module in any way. Perl pseudo-threads
650 is evil stuff and must die. As soon as Perl gains real threads I will 733 is evil stuff and must die. As soon as Perl gains real threads I will
651 work on thread support for it. 734 work on thread support for it.
666 749
667 On win32, there is no notion of fork so all this doesn't apply, of 750 On win32, there is no notion of fork so all this doesn't apply, of
668 course. 751 course.
669 752
670SEE ALSO 753SEE ALSO
671 EV::ADNS (asynchronous dns), Glib::EV (makes Glib/Gtk2 use EV as event 754 EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event
672 loop), Coro::EV (efficient coroutines with EV). 755 loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines
756 with EV), Net::SNMP::EV (asynchronous SNMP).
673 757
674AUTHOR 758AUTHOR
675 Marc Lehmann <schmorp@schmorp.de> 759 Marc Lehmann <schmorp@schmorp.de>
676 http://home.schmorp.de/ 760 http://home.schmorp.de/
677 761

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