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Revision 1.23 by root, Sat Mar 8 16:00:07 2008 UTC vs.
Revision 1.32 by root, Tue Apr 28 00:50:57 2009 UTC

1NAME 1NAME
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
8 # TIMERS
9
10 my $w = EV::timer 2, 0, sub {
11 warn "is called after 2s";
12 };
13
14 my $w = EV::timer 2, 2, sub {
15 warn "is called roughly every 2s (repeat = 2)";
16 };
17
18 undef $w; # destroy event watcher again
19
20 my $w = EV::periodic 0, 60, 0, sub {
21 warn "is called every minute, on the minute, exactly";
22 };
23
24 # IO
25
26 my $w = EV::io *STDIN, EV::READ, sub {
27 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
28 warn "stdin is readable, you entered: ", <STDIN>;
29 };
30
31 # SIGNALS
32
33 my $w = EV::signal 'QUIT', sub {
34 warn "sigquit received\n";
35 };
36
37 # CHILD/PID STATUS CHANGES
7 38
8 # TIMERS 39 my $w = EV::child 666, 0, sub {
40 my ($w, $revents) = @_;
41 my $status = $w->rstatus;
42 };
9 43
10 my $w = EV::timer 2, 0, sub {
11 warn "is called after 2s";
12 };
13
14 my $w = EV::timer 2, 2, sub {
15 warn "is called roughly every 2s (repeat = 2)";
16 };
17
18 undef $w; # destroy event watcher again
19
20 my $w = EV::periodic 0, 60, 0, sub {
21 warn "is called every minute, on the minute, exactly";
22 };
23
24 # IO
25
26 my $w = EV::io *STDIN, EV::READ, sub {
27 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
28 warn "stdin is readable, you entered: ", <STDIN>;
29 };
30
31 # SIGNALS
32
33 my $w = EV::signal 'QUIT', sub {
34 warn "sigquit received\n";
35 };
36
37 # CHILD/PID STATUS CHANGES
38
39 my $w = EV::child 666, 0, sub {
40 my ($w, $revents) = @_;
41 my $status = $w->rstatus;
42 };
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 54
55DESCRIPTION 55DESCRIPTION
56 This module provides an interface to libev 56 This module provides an interface to libev
57 (<http://software.schmorp.de/pkg/libev.html>). While the documentation 57 (<http://software.schmorp.de/pkg/libev.html>). While the documentation
58 below is comprehensive, one might also consult the documentation of 58 below is comprehensive, one might also consult the documentation of
59 libev itself (<http://cvs.schmorp.de/libev/ev.html>) for more subtle 59 libev itself (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
60 details on watcher semantics or some discussion on the available 60 perldoc EV::libev) for more subtle details on watcher semantics or some
61 backends, or how to force a specific backend with "LIBEV_FLAGS", or just 61 discussion on the available backends, or how to force a specific backend
62 about in any case because it has much more detailed information. 62 with "LIBEV_FLAGS", or just about in any case because it has much more
63 detailed information.
64
65 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
67 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
69 in Perl.
70
71 MODULE EXPORTS
72 This module does not export any symbols.
63 73
64EVENT LOOPS 74EVENT LOOPS
65 EV supports multiple event loops: There is a single "default event loop" 75 EV supports multiple event loops: There is a single "default event loop"
66 that can handle everything including signals and child watchers, and any 76 that can handle everything including signals and child watchers, and any
67 number of "dynamic event loops" that can use different backends (with 77 number of "dynamic event loops" that can use different backends (with
… …
74 default loop as this is fastest (perl-wise), best supported by other 84 default loop as this is fastest (perl-wise), best supported by other
75 modules (e.g. AnyEvent or Coro) and most portable event loop. 85 modules (e.g. AnyEvent or Coro) and most portable event loop.
76 86
77 For specific programs you can create additional event loops dynamically. 87 For specific programs you can create additional event loops dynamically.
78 88
89 If you want to take advantage of kqueue (which often works properly for
90 sockets only) even though the default loop doesn't enable it, you can
91 *embed* a kqueue loop into the default loop: running the default loop
92 will then also service the kqueue loop to some extent. See the example
93 in the section about embed watchers for an example on how to achieve
94 that.
95
79 $loop = new EV::loop [$flags] 96 $loop = new EV::Loop [$flags]
80 Create a new event loop as per the specified flags. Please refer to 97 Create a new event loop as per the specified flags. Please refer to
81 the "ev_loop_new ()" function description in the libev documentation 98 the "ev_loop_new ()" function description in the libev documentation
82 (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI 99 (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI
83 ONS>) for more info. 100 ONS>, or locally-installed as EV::libev manpage) for more info.
84 101
85 The loop will automatically be destroyed when it is no longer 102 The loop will automatically be destroyed when it is no longer
86 referenced by any watcher and the loop object goes out of scope. 103 referenced by any watcher and the loop object goes out of scope.
87 104
88 Using "EV::FLAG_FORKCHECK" is recommended, as only the default event 105 If you are not embedding the loop, then Using "EV::FLAG_FORKCHECK"
89 loop is protected by this module. 106 is recommended, as only the default event loop is protected by this
107 module. If you *are* embedding this loop in the default loop, this
108 is not necessary, as "EV::embed" automatically does the right thing
109 on fork.
90 110
91 $loop->loop_fork 111 $loop->loop_fork
92 Must be called after a fork in the child, before entering or 112 Must be called after a fork in the child, before entering or
93 continuing the event loop. An alternative is to use 113 continuing the event loop. An alternative is to use
94 "EV::FLAG_FORKCHECK" which calls this fucntion automatically, at 114 "EV::FLAG_FORKCHECK" which calls this function automatically, at
95 some performance loss (refer to the libev documentation). 115 some performance loss (refer to the libev documentation).
96 116
117 $loop->loop_verify
118 Calls "ev_verify" to make internal consistency checks (for debugging
119 libev) and abort the program if any data structures were found to be
120 corrupted.
121
97 $loop = EV::default_loop [$flags] 122 $loop = EV::default_loop [$flags]
98 Return the default loop (which is a singleton object). 123 Return the default loop (which is a singleton object). Since this
124 module already creates the default loop with default flags,
125 specifying flags here will not have any effect unless you destroy
126 the default loop first, which isn't supported. So in short: don't do
127 it, and if you break it, you get to keep the pieces.
99 128
100BASIC INTERFACE 129BASIC INTERFACE
101 $EV::DIED 130 $EV::DIED
102 Must contain a reference to a function that is called when a 131 Must contain a reference to a function that is called when a
103 callback throws an exception (with $@ containing the error). The 132 callback throws an exception (with $@ containing the error). The
… …
120 Returns the current time in (fractional) seconds since the epoch. 149 Returns the current time in (fractional) seconds since the epoch.
121 150
122 $time = EV::now 151 $time = EV::now
123 $time = $loop->now 152 $time = $loop->now
124 Returns the time the last event loop iteration has been started. 153 Returns the time the last event loop iteration has been started.
125 This is the time that (relative) timers are based on, and refering 154 This is the time that (relative) timers are based on, and referring
126 to it is usually faster then calling EV::time. 155 to it is usually faster then calling EV::time.
156
157 EV::now_update
158 $loop->now_update
159 Establishes the current time by querying the kernel, updating the
160 time returned by "EV::now" in the progress. This is a costly
161 operation and is usually done automatically within "EV::loop".
162
163 This function is rarely useful, but when some event callback runs
164 for a very long time without entering the event loop, updating
165 libev's idea of the current time is a good idea.
166
167 EV::suspend
168 $loop->suspend
169 EV::resume
170 $loop->resume
171 These two functions suspend and resume a loop, for use when the loop
172 is not used for a while and timeouts should not be processed.
173
174 A typical use case would be an interactive program such as a game:
175 When the user presses "^Z" to suspend the game and resumes it an
176 hour later it would be best to handle timeouts as if no time had
177 actually passed while the program was suspended. This can be
178 achieved by calling "suspend" in your "SIGTSTP" handler, sending
179 yourself a "SIGSTOP" and calling "resume" directly afterwards to
180 resume timer processing.
181
182 Effectively, all "timer" watchers will be delayed by the time spend
183 between "suspend" and "resume", and all "periodic" watchers will be
184 rescheduled (that is, they will lose any events that would have
185 occured while suspended).
186
187 After calling "suspend" you must not call *any* function on the
188 given loop other than "resume", and you must not call "resume"
189 without a previous call to "suspend".
190
191 Calling "suspend"/"resume" has the side effect of updating the event
192 loop time (see "now_update").
127 193
128 $backend = EV::backend 194 $backend = EV::backend
129 $backend = $loop->backend 195 $backend = $loop->backend
130 Returns an integer describing the backend used by libev 196 Returns an integer describing the backend used by libev
131 (EV::METHOD_SELECT or EV::METHOD_EPOLL). 197 (EV::BACKEND_SELECT or EV::BACKEND_EPOLL).
132 198
133 EV::loop [$flags] 199 EV::loop [$flags]
134 $loop->loop ([$flags]) 200 $loop->loop ([$flags])
135 Begin checking for events and calling callbacks. It returns when a 201 Begin checking for events and calling callbacks. It returns when a
136 callback calls EV::unloop. 202 callback calls EV::unloop.
… …
150 EV::loop will return as fast as possible. 216 EV::loop will return as fast as possible.
151 217
152 $count = EV::loop_count 218 $count = EV::loop_count
153 $count = $loop->loop_count 219 $count = $loop->loop_count
154 Return the number of times the event loop has polled for new events. 220 Return the number of times the event loop has polled for new events.
155 Sometiems useful as a generation counter. 221 Sometimes useful as a generation counter.
156 222
157 EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 223 EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
158 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 224 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
159 This function rolls together an I/O and a timer watcher for a single 225 This function rolls together an I/O and a timer watcher for a single
160 one-shot event without the need for managing a watcher object. 226 one-shot event without the need for managing a watcher object.
… …
194 $loop->set_timeout_collect_interval ($time) 260 $loop->set_timeout_collect_interval ($time)
195 These advanced functions set the minimum block interval when polling 261 These advanced functions set the minimum block interval when polling
196 for I/O events and the minimum wait interval for timer events. See 262 for I/O events and the minimum wait interval for timer events. See
197 the libev documentation at 263 the libev documentation at
198 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT 264 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT
199 ROLLING_THE_EVENT_LOOP> for a more detailed discussion. 265 ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more
266 detailed discussion.
200 267
201WATCHER OBJECTS 268WATCHER OBJECTS
202 A watcher is an object that gets created to record your interest in some 269 A watcher is an object that gets created to record your interest in some
203 event. For instance, if you want to wait for STDIN to become readable, 270 event. For instance, if you want to wait for STDIN to become readable,
204 you would create an EV::io watcher for that: 271 you would create an EV::io watcher for that:
205 272
206 my $watcher = EV::io *STDIN, EV::READ, sub { 273 my $watcher = EV::io *STDIN, EV::READ, sub {
207 my ($watcher, $revents) = @_; 274 my ($watcher, $revents) = @_;
208 warn "yeah, STDIN should now be readable without blocking!\n" 275 warn "yeah, STDIN should now be readable without blocking!\n"
209 }; 276 };
210 277
211 All watchers can be active (waiting for events) or inactive (paused). 278 All watchers can be active (waiting for events) or inactive (paused).
212 Only active watchers will have their callbacks invoked. All callbacks 279 Only active watchers will have their callbacks invoked. All callbacks
213 will be called with at least two arguments: the watcher and a bitmask of 280 will be called with at least two arguments: the watcher and a bitmask of
214 received events. 281 received events.
215 282
216 Each watcher type has its associated bit in revents, so you can use the 283 Each watcher type has its associated bit in revents, so you can use the
217 same callback for multiple watchers. The event mask is named after the 284 same callback for multiple watchers. The event mask is named after the
218 type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 285 type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
219 EV::periodic sets EV::PERIODIC and so on, with the exception of I/O 286 EV::periodic sets EV::PERIODIC and so on, with the exception of I/O
220 events (which can set both EV::READ and EV::WRITE bits), and EV::timer 287 events (which can set both EV::READ and EV::WRITE bits), and EV::timer
221 (which uses EV::TIMEOUT). 288 (which uses EV::TIMEOUT).
222 289
223 In the rare case where one wants to create a watcher but not start it at 290 In the rare case where one wants to create a watcher but not start it at
… …
308 375
309 In this case you can clear the keepalive status, which means that 376 In this case you can clear the keepalive status, which means that
310 even though your watcher is active, it won't keep "EV::loop" from 377 even though your watcher is active, it won't keep "EV::loop" from
311 returning. 378 returning.
312 379
313 The initial value for keepalive is true (enabled), and you cna 380 The initial value for keepalive is true (enabled), and you can
314 change it any time. 381 change it any time.
315 382
316 Example: Register an I/O watcher for some UDP socket but do not keep 383 Example: Register an I/O watcher for some UDP socket but do not keep
317 the event loop from running just because of that watcher. 384 the event loop from running just because of that watcher.
318 385
319 my $udp_socket = ... 386 my $udp_socket = ...
320 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 387 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
321 $1000udp_watcher->keepalive (0); 388 $udp_watcher->keepalive (0);
322 389
323 $loop = $w->loop 390 $loop = $w->loop
324 Return the loop that this watcher is attached to. 391 Return the loop that this watcher is attached to.
325 392
326WATCHER TYPES 393WATCHER TYPES
… …
449 each time the periodic watcher gets scheduled, the reschedule 516 each time the periodic watcher gets scheduled, the reschedule
450 callback ($reschedule_cb) will be called with the watcher as 517 callback ($reschedule_cb) will be called with the watcher as
451 first, and the current time as second argument. 518 first, and the current time as second argument.
452 519
453 *This callback MUST NOT stop or destroy this or any other 520 *This callback MUST NOT stop or destroy this or any other
521 periodic watcher, ever, and MUST NOT call any event loop
454 periodic watcher, ever*. If you need to stop it, return 1e30 and 522 functions or methods*. If you need to stop it, return 1e30 and
455 stop it afterwards. 523 stop it afterwards. You may create and start a "EV::prepare"
524 watcher for this task.
456 525
457 It must return the next time to trigger, based on the passed 526 It must return the next time to trigger, based on the passed
458 time value (that is, the lowest time value larger than to the 527 time value (that is, the lowest time value larger than or equal
459 second argument). It will usually be called just before the 528 to to the second argument). It will usually be called just
460 callback will be triggered, but might be called at other times, 529 before the callback will be triggered, but might be called at
461 too. 530 other times, too.
462 531
463 This can be used to create very complex timers, such as a timer 532 This can be used to create very complex timers, such as a timer
464 that triggers on each midnight, local time (actually 24 hours 533 that triggers on each midnight, local time (actually 24 hours
465 after the last midnight, to keep the example simple. If you know 534 after the last midnight, to keep the example simple. If you know
466 a way to do it correctly in about the same space (without 535 a way to do it correctly in about the same space (without
… …
716 # make the dispatcher handle any new stuff 785 # make the dispatcher handle any new stuff
717 ... not shown 786 ... not shown
718 }; 787 };
719 788
720 The callbacks of the created watchers will not be called as the 789 The callbacks of the created watchers will not be called as the
721 watchers are destroyed before this cna happen (remember EV::check 790 watchers are destroyed before this can happen (remember EV::check
722 gets called first). 791 gets called first).
723 792
724 The "check_ns" variant doesn't start (activate) the newly created 793 The "check_ns" variant doesn't start (activate) the newly created
725 watcher. 794 watcher.
726 795
… …
745 embedded loop, other types of watchers might be handled in a delayed or 814 embedded loop, other types of watchers might be handled in a delayed or
746 incorrect fashion and must not be used). 815 incorrect fashion and must not be used).
747 816
748 See the libev documentation at 817 See the libev documentation at
749 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code 818 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code
750 _when_one_backend_> for more details. 819 _when_one_backend_> (locally installed as EV::libev) for more details.
751 820
752 In short, this watcher is most useful on BSD systems without working 821 In short, this watcher is most useful on BSD systems without working
753 kqueue to still be able to handle a large number of sockets: 822 kqueue to still be able to handle a large number of sockets:
754 823
755 my $socket_loop; 824 my $socket_loop;
756 825
757 # check wether we use SELECT or POLL _and_ KQUEUE is supported 826 # check wether we use SELECT or POLL _and_ KQUEUE is supported
758 if ( 827 if (
759 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 828 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
760 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 829 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
761 ) { 830 ) {
762 # use kqueue for sockets 831 # use kqueue for sockets
763 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 832 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
764 } 833 }
765 834
766 # use the default loop otherwise 835 # use the default loop otherwise
767 $socket_loop ||= EV::default_loop; 836 $socket_loop ||= EV::default_loop;
768 837
769 $w = EV::embed $otherloop, $callback 838 $w = EV::embed $otherloop[, $callback]
770 $w = EV::embed_ns $otherloop, $callback 839 $w = EV::embed_ns $otherloop[, $callback]
771 $w = $loop->embed ($otherloop, $callback) 840 $w = $loop->embed ($otherloop[, $callback])
772 $w = $loop->embed_ns ($otherloop, $callback) 841 $w = $loop->embed_ns ($otherloop[, $callback])
773 Call the callback when the embedded event loop ($otherloop) has any 842 Call the callback when the embedded event loop ($otherloop) has any
774 I/O activity. The $callback should alwas be specified as "undef" in 843 I/O activity. The $callback is optional: if it is missing, then the
775 this version of EV, which means the embedded event loop will be 844 embedded event loop will be managed automatically (which is
776 managed automatically. 845 recommended), otherwise you have to invoke "sweep" yourself.
777 846
778 The "embed_ns" variant doesn't start (activate) the newly created 847 The "embed_ns" variant doesn't start (activate) the newly created
779 watcher. 848 watcher.
780 849
781 ASYNC WATCHERS - how to wake up another event loop 850 ASYNC WATCHERS - how to wake up another event loop
… …
784 other contexts where they could be of value. 853 other contexts where they could be of value.
785 854
786 It is, however, possible to use them from the XS level. 855 It is, however, possible to use them from the XS level.
787 856
788 Please see the libev documentation for further details. 857 Please see the libev documentation for further details.
858
859 $w = EV::async $callback
860 $w = EV::async_ns $callback
861 $w->send
862 $bool = $w->async_pending
789 863
790PERL SIGNALS 864PERL SIGNALS
791 While Perl signal handling (%SIG) is not affected by EV, the behaviour 865 While Perl signal handling (%SIG) is not affected by EV, the behaviour
792 with EV is as the same as any other C library: Perl-signals will only be 866 with EV is as the same as any other C library: Perl-signals will only be
793 handled when Perl runs, which means your signal handler might be invoked 867 handled when Perl runs, which means your signal handler might be invoked
… …
828 course. 902 course.
829 903
830SEE ALSO 904SEE ALSO
831 EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event 905 EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event
832 loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines 906 loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines
833 with EV), Net::SNMP::EV (asynchronous SNMP). 907 with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop
908 agnostic and portable event driven programming.
834 909
835AUTHOR 910AUTHOR
836 Marc Lehmann <schmorp@schmorp.de> 911 Marc Lehmann <schmorp@schmorp.de>
837 http://home.schmorp.de/ 912 http://home.schmorp.de/
838 913

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