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Revision 1.29 by root, Sat Jul 12 22:19:22 2008 UTC vs.
Revision 1.36 by root, Thu Oct 21 02:46:59 2010 UTC

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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::loop; # loop until EV::unloop is called or all watchers stop
52 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled 52 EV::loop EV::LOOP_ONESHOT; # 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::loop EV::LOOP_NONBLOCK; # 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 MODULE EXPORTS
81 This module does not export any symbols.
70 82
71EVENT LOOPS 83EVENT LOOPS
72 EV supports multiple event loops: There is a single "default event loop" 84 EV supports multiple event loops: There is a single "default event loop"
73 that can handle everything including signals and child watchers, and any 85 that can handle everything including signals and child watchers, and any
74 number of "dynamic event loops" that can use different backends (with 86 number of "dynamic event loops" that can use different backends (with
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81 default loop as this is fastest (perl-wise), best supported by other 93 default loop as this is fastest (perl-wise), best supported by other
82 modules (e.g. AnyEvent or Coro) and most portable event loop. 94 modules (e.g. AnyEvent or Coro) and most portable event loop.
83 95
84 For specific programs you can create additional event loops dynamically. 96 For specific programs you can create additional event loops dynamically.
85 97
86 If you want to take avdantage of kqueue (which often works properly for 98 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 99 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 100 *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 101 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 102 in the section about embed watchers for an example on how to achieve
91 that. 103 that.
92 104
93 $loop = new EV::loop [$flags] 105 $loop = new EV::Loop [$flags]
94 Create a new event loop as per the specified flags. Please refer to 106 Create a new event loop as per the specified flags. Please refer to
95 the "ev_loop_new ()" function description in the libev documentation 107 the "ev_loop_new ()" function description in the libev documentation
96 (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI 108 (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI
97 ONS>) for more info. 109 ONS>, or locally-installed as EV::libev manpage) for more info.
98 110
99 The loop will automatically be destroyed when it is no longer 111 The loop will automatically be destroyed when it is no longer
100 referenced by any watcher and the loop object goes out of scope. 112 referenced by any watcher and the loop object goes out of scope.
101 113
102 Using "EV::FLAG_FORKCHECK" is recommended, as only the default event 114 If you are not embedding the loop, then Using "EV::FLAG_FORKCHECK"
103 loop is protected by this module. 115 is recommended, as only the default event loop is protected by this
116 module. If you *are* embedding this loop in the default loop, this
117 is not necessary, as "EV::embed" automatically does the right thing
118 on fork.
104 119
105 $loop->loop_fork 120 $loop->loop_fork
106 Must be called after a fork in the child, before entering or 121 Must be called after a fork in the child, before entering or
107 continuing the event loop. An alternative is to use 122 continuing the event loop. An alternative is to use
108 "EV::FLAG_FORKCHECK" which calls this function automatically, at 123 "EV::FLAG_FORKCHECK" which calls this function automatically, at
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143 Returns the current time in (fractional) seconds since the epoch. 158 Returns the current time in (fractional) seconds since the epoch.
144 159
145 $time = EV::now 160 $time = EV::now
146 $time = $loop->now 161 $time = $loop->now
147 Returns the time the last event loop iteration has been started. 162 Returns the time the last event loop iteration has been started.
148 This is the time that (relative) timers are based on, and refering 163 This is the time that (relative) timers are based on, and referring
149 to it is usually faster then calling EV::time. 164 to it is usually faster then calling EV::time.
165
166 EV::now_update
167 $loop->now_update
168 Establishes the current time by querying the kernel, updating the
169 time returned by "EV::now" in the progress. This is a costly
170 operation and is usually done automatically within "EV::loop".
171
172 This function is rarely useful, but when some event callback runs
173 for a very long time without entering the event loop, updating
174 libev's idea of the current time is a good idea.
175
176 EV::suspend
177 $loop->suspend
178 EV::resume
179 $loop->resume
180 These two functions suspend and resume a loop, for use when the loop
181 is not used for a while and timeouts should not be processed.
182
183 A typical use case would be an interactive program such as a game:
184 When the user presses "^Z" to suspend the game and resumes it an
185 hour later it would be best to handle timeouts as if no time had
186 actually passed while the program was suspended. This can be
187 achieved by calling "suspend" in your "SIGTSTP" handler, sending
188 yourself a "SIGSTOP" and calling "resume" directly afterwards to
189 resume timer processing.
190
191 Effectively, all "timer" watchers will be delayed by the time spend
192 between "suspend" and "resume", and all "periodic" watchers will be
193 rescheduled (that is, they will lose any events that would have
194 occured while suspended).
195
196 After calling "suspend" you must not call *any* function on the
197 given loop other than "resume", and you must not call "resume"
198 without a previous call to "suspend".
199
200 Calling "suspend"/"resume" has the side effect of updating the event
201 loop time (see "now_update").
150 202
151 $backend = EV::backend 203 $backend = EV::backend
152 $backend = $loop->backend 204 $backend = $loop->backend
153 Returns an integer describing the backend used by libev 205 Returns an integer describing the backend used by libev
154 (EV::METHOD_SELECT or EV::METHOD_EPOLL). 206 (EV::BACKEND_SELECT or EV::BACKEND_EPOLL).
155 207
156 EV::loop [$flags] 208 EV::loop [$flags]
157 $loop->loop ([$flags]) 209 $loop->loop ([$flags])
158 Begin checking for events and calling callbacks. It returns when a 210 Begin checking for events and calling callbacks. It returns when a
159 callback calls EV::unloop. 211 callback calls EV::unloop.
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173 EV::loop will return as fast as possible. 225 EV::loop will return as fast as possible.
174 226
175 $count = EV::loop_count 227 $count = EV::loop_count
176 $count = $loop->loop_count 228 $count = $loop->loop_count
177 Return the number of times the event loop has polled for new events. 229 Return the number of times the event loop has polled for new events.
178 Sometiems useful as a generation counter. 230 Sometimes useful as a generation counter.
179 231
180 EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 232 EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
181 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 233 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
182 This function rolls together an I/O and a timer watcher for a single 234 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. 235 one-shot event without the need for managing a watcher object.
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192 Otherwise a EV::timer with this value will be started. 244 Otherwise a EV::timer with this value will be started.
193 245
194 When an error occurs or either the timeout or I/O watcher triggers, 246 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 247 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", 248 general you can expect it to be a combination of "EV::ERROR",
197 "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). 249 "EV::READ", "EV::WRITE" and "EV::TIMER").
198 250
199 EV::once doesn't return anything: the watchers stay active till 251 EV::once doesn't return anything: the watchers stay active till
200 either of them triggers, then they will be stopped and freed, and 252 either of them triggers, then they will be stopped and freed, and
201 the callback invoked. 253 the callback invoked.
202 254
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217 $loop->set_timeout_collect_interval ($time) 269 $loop->set_timeout_collect_interval ($time)
218 These advanced functions set the minimum block interval when polling 270 These advanced functions set the minimum block interval when polling
219 for I/O events and the minimum wait interval for timer events. See 271 for I/O events and the minimum wait interval for timer events. See
220 the libev documentation at 272 the libev documentation at
221 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT 273 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT
222 ROLLING_THE_EVENT_LOOP> for a more detailed discussion. 274 ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more
275 detailed discussion.
276
277 $count = EV::pending_count
278 $count = $loop->pending_count
279 Returns the number of currently pending watchers.
280
281 EV::invoke_pending
282 $loop->invoke_pending
283 Invoke all currently pending watchers.
223 284
224WATCHER OBJECTS 285WATCHER OBJECTS
225 A watcher is an object that gets created to record your interest in some 286 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, 287 event. For instance, if you want to wait for STDIN to become readable,
227 you would create an EV::io watcher for that: 288 you would create an EV::io watcher for that:
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236 will be called with at least two arguments: the watcher and a bitmask of 297 will be called with at least two arguments: the watcher and a bitmask of
237 received events. 298 received events.
238 299
239 Each watcher type has its associated bit in revents, so you can use the 300 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 301 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, 302 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 303 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 304 events (which can set both EV::READ and EV::WRITE bits).
244 (which uses EV::TIMEOUT).
245 305
246 In the rare case where one wants to create a watcher but not start it at 306 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 307 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. 308 its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
249 309
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314 the watcher isn't pending it does nothing and returns 0. 374 the watcher isn't pending it does nothing and returns 0.
315 375
316 $previous_state = $w->keepalive ($bool) 376 $previous_state = $w->keepalive ($bool)
317 Normally, "EV::loop" will return when there are no active watchers 377 Normally, "EV::loop" will return when there are no active watchers
318 (which is a "deadlock" because no progress can be made anymore). 378 (which is a "deadlock" because no progress can be made anymore).
319 This is convinient because it allows you to start your watchers (and 379 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 380 your jobs), call "EV::loop" once and when it returns you know that
321 all your jobs are finished (or they forgot to register some watchers 381 all your jobs are finished (or they forgot to register some watchers
322 for their task :). 382 for their task :).
323 383
324 Sometimes, however, this gets in your way, for example when the 384 Sometimes, however, this gets in your way, for example when the
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331 391
332 In this case you can clear the keepalive status, which means that 392 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 393 even though your watcher is active, it won't keep "EV::loop" from
334 returning. 394 returning.
335 395
336 The initial value for keepalive is true (enabled), and you cna 396 The initial value for keepalive is true (enabled), and you can
337 change it any time. 397 change it any time.
338 398
339 Example: Register an I/O watcher for some UDP socket but do not keep 399 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. 400 the event loop from running just because of that watcher.
341 401
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515 Return the time that the watcher is expected to trigger next. 575 Return the time that the watcher is expected to trigger next.
516 576
517 SIGNAL WATCHERS - signal me when a signal gets signalled! 577 SIGNAL WATCHERS - signal me when a signal gets signalled!
518 $w = EV::signal $signal, $callback 578 $w = EV::signal $signal, $callback
519 $w = EV::signal_ns $signal, $callback 579 $w = EV::signal_ns $signal, $callback
580 $w = $loop->signal ($signal, $callback)
581 $w = $loop->signal_ns ($signal, $callback)
520 Call the callback when $signal is received (the signal can be 582 Call the callback when $signal is received (the signal can be
521 specified by number or by name, just as with "kill" or %SIG). 583 specified by number or by name, just as with "kill" or %SIG).
584
585 Only one event loop can grab a given signal - attempting to grab the
586 same signal from two EV loops will crash the program immediately or
587 cause data corruption.
522 588
523 EV will grab the signal for the process (the kernel only allows one 589 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 590 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 591 watcher, and removes it again when you stop it. Perl does the same
526 when you add/remove callbacks to %SIG, so watch out. 592 when you add/remove callbacks to %SIG, so watch out.
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741 # make the dispatcher handle any new stuff 807 # make the dispatcher handle any new stuff
742 ... not shown 808 ... not shown
743 }; 809 };
744 810
745 The callbacks of the created watchers will not be called as the 811 The callbacks of the created watchers will not be called as the
746 watchers are destroyed before this cna happen (remember EV::check 812 watchers are destroyed before this can happen (remember EV::check
747 gets called first). 813 gets called first).
748 814
749 The "check_ns" variant doesn't start (activate) the newly created 815 The "check_ns" variant doesn't start (activate) the newly created
750 watcher. 816 watcher.
751 817
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770 embedded loop, other types of watchers might be handled in a delayed or 836 embedded loop, other types of watchers might be handled in a delayed or
771 incorrect fashion and must not be used). 837 incorrect fashion and must not be used).
772 838
773 See the libev documentation at 839 See the libev documentation at
774 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code 840 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code
775 _when_one_backend_> for more details. 841 _when_one_backend_> (locally installed as EV::libev) for more details.
776 842
777 In short, this watcher is most useful on BSD systems without working 843 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: 844 kqueue to still be able to handle a large number of sockets:
779 845
780 my $socket_loop; 846 my $socket_loop;
781 847
782 # check wether we use SELECT or POLL _and_ KQUEUE is supported 848 # check wether we use SELECT or POLL _and_ KQUEUE is supported
783 if ( 849 if (
784 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 850 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
785 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 851 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
786 ) { 852 ) {
787 # use kqueue for sockets 853 # use kqueue for sockets
788 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 854 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
789 } 855 }
790 856
791 # use the default loop otherwise 857 # use the default loop otherwise
792 $socket_loop ||= EV::default_loop; 858 $socket_loop ||= EV::default_loop;
793 859
794 $w = EV::embed $otherloop[, $callback] 860 $w = EV::embed $otherloop[, $callback]
795 $w = EV::embed_ns $otherloop[, $callback] 861 $w = EV::embed_ns $otherloop[, $callback]
796 $w = $loop->embed ($otherloop[, $callback]) 862 $w = $loop->embed ($otherloop[, $callback])
… …
803 The "embed_ns" variant doesn't start (activate) the newly created 869 The "embed_ns" variant doesn't start (activate) the newly created
804 watcher. 870 watcher.
805 871
806 ASYNC WATCHERS - how to wake up another event loop 872 ASYNC WATCHERS - how to wake up another event loop
807 Async watchers are provided by EV, but have little use in perl directly, 873 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 874 as perl neither supports threads running in parallel nor direct access
809 other contexts where they could be of value. 875 to signal handlers or other contexts where they could be of value.
810 876
811 It is, however, possible to use them from the XS level. 877 It is, however, possible to use them from the XS level.
812 878
813 Please see the libev documentation for further details. 879 Please see the libev documentation for further details.
814 880
… …
833 my $async_check = EV::check sub { }; 899 my $async_check = EV::check sub { };
834 900
835 This ensures that perl gets into control for a short time to handle any 901 This ensures that perl gets into control for a short time to handle any
836 pending signals, and also ensures (slightly) slower overall operation. 902 pending signals, and also ensures (slightly) slower overall operation.
837 903
838THREADS 904ITHREADS
839 Threads are not supported by this module in any way. Perl pseudo-threads 905 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 906 pseudo-threads is evil stuff and must die. Real threads as provided by
841 work on thread support for it. 907 Coro are fully supported (and enhanced support is available via
908 Coro::EV).
842 909
843FORK 910FORK
844 Most of the "improved" event delivering mechanisms of modern operating 911 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 912 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 913 not supported and usually destructive). Libev makes it possible to work

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