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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 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, 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 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
… …
72 selecting a working backend (which for example rules out kqueue on most 82 selecting a working backend (which for example rules out kqueue on most
73 BSDs). Modules should, unless they have "special needs" always use the 83 BSDs). Modules should, unless they have "special needs" always use the
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 cna create additional event loops dynamically. 87 For specific programs you can create additional event loops dynamically.
88
89 If you want to take avdantage 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.
78 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).
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
122 $loop = EV::default_loop [$flags]
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.
96 128
97BASIC INTERFACE 129BASIC INTERFACE
98 $EV::DIED 130 $EV::DIED
99 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
100 callback throws an exception (with $@ containing the error). The 132 callback throws an exception (with $@ containing the error). The
101 default prints an informative message and continues. 133 default prints an informative message and continues.
102 134
103 If this callback throws an exception it will be silently ignored. 135 If this callback throws an exception it will be silently ignored.
136
137 $flags = EV::supported_backends
138 $flags = EV::recommended_backends
139 $flags = EV::embeddable_backends
140 Returns the set (see "EV::BACKEND_*" flags) of backends supported by
141 this instance of EV, the set of recommended backends (supposed to be
142 good) for this platform and the set of embeddable backends (see
143 EMBED WATCHERS).
144
145 EV::sleep $seconds
146 Block the process for the given number of (fractional) seconds.
104 147
105 $time = EV::time 148 $time = EV::time
106 Returns the current time in (fractional) seconds since the epoch. 149 Returns the current time in (fractional) seconds since the epoch.
107 150
108 $time = EV::now 151 $time = EV::now
… …
172 215
173 EV::feed_signal_event ($signal) 216 EV::feed_signal_event ($signal)
174 Feed a signal event into EV. EV will react to this call as if the 217 Feed a signal event into EV. EV will react to this call as if the
175 signal specified by $signal had occured. 218 signal specified by $signal had occured.
176 219
220 EV::set_io_collect_interval $time
221 $loop->set_io_collect_interval ($time)
222 EV::set_timeout_collect_interval $time
223 $loop->set_timeout_collect_interval ($time)
224 These advanced functions set the minimum block interval when polling
225 for I/O events and the minimum wait interval for timer events. See
226 the libev documentation at
227 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT
228 ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more
229 detailed discussion.
230
177WATCHER OBJECTS 231WATCHER OBJECTS
178 A watcher is an object that gets created to record your interest in some 232 A watcher is an object that gets created to record your interest in some
179 event. For instance, if you want to wait for STDIN to become readable, 233 event. For instance, if you want to wait for STDIN to become readable,
180 you would create an EV::io watcher for that: 234 you would create an EV::io watcher for that:
181 235
182 my $watcher = EV::io *STDIN, EV::READ, sub { 236 my $watcher = EV::io *STDIN, EV::READ, sub {
183 my ($watcher, $revents) = @_; 237 my ($watcher, $revents) = @_;
184 warn "yeah, STDIN should now be readable without blocking!\n" 238 warn "yeah, STDIN should now be readable without blocking!\n"
185 }; 239 };
186 240
187 All watchers can be active (waiting for events) or inactive (paused). 241 All watchers can be active (waiting for events) or inactive (paused).
188 Only active watchers will have their callbacks invoked. All callbacks 242 Only active watchers will have their callbacks invoked. All callbacks
189 will be called with at least two arguments: the watcher and a bitmask of 243 will be called with at least two arguments: the watcher and a bitmask of
190 received events. 244 received events.
… …
292 Example: Register an I/O watcher for some UDP socket but do not keep 346 Example: Register an I/O watcher for some UDP socket but do not keep
293 the event loop from running just because of that watcher. 347 the event loop from running just because of that watcher.
294 348
295 my $udp_socket = ... 349 my $udp_socket = ...
296 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 350 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
297 $1000udp_watcher->keepalive (0); 351 $udp_watcher->keepalive (0);
298 352
299 $loop = $w->loop 353 $loop = $w->loop
300 Return the loop that this watcher is attached to. 354 Return the loop that this watcher is attached to.
301 355
302WATCHER TYPES 356WATCHER TYPES
… …
390 changed by explicit date -s or other means such as ntpd). It is also 444 changed by explicit date -s or other means such as ntpd). It is also
391 the most complex watcher type in EV. 445 the most complex watcher type in EV.
392 446
393 It has three distinct "modes": 447 It has three distinct "modes":
394 448
395 * absolute timer ($interval = $reschedule_cb = 0) 449 * absolute timer ($interval = $reschedule_cb = 0)
450
396 This time simply fires at the wallclock time $at and doesn't 451 This time simply fires at the wallclock time $at and doesn't
397 repeat. It will not adjust when a time jump occurs, that is, if 452 repeat. It will not adjust when a time jump occurs, that is, if
398 it is to be run at January 1st 2011 then it will run when the 453 it is to be run at January 1st 2011 then it will run when the
399 system time reaches or surpasses this time. 454 system time reaches or surpasses this time.
400 455
401 * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 456 * repeating interval timer ($interval > 0, $reschedule_cb = 0)
457
402 In this mode the watcher will always be scheduled to time out at 458 In this mode the watcher will always be scheduled to time out at
403 the next "$at + N * $interval" time (for some integer N) and 459 the next "$at + N * $interval" time (for some integer N) and
404 then repeat, regardless of any time jumps. 460 then repeat, regardless of any time jumps.
405 461
406 This can be used to create timers that do not drift with respect 462 This can be used to create timers that do not drift with respect
… …
415 Another way to think about it (for the mathematically inclined) 471 Another way to think about it (for the mathematically inclined)
416 is that EV::periodic will try to run the callback in this mode 472 is that EV::periodic will try to run the callback in this mode
417 at the next possible time where "$time = $at (mod $interval)", 473 at the next possible time where "$time = $at (mod $interval)",
418 regardless of any time jumps. 474 regardless of any time jumps.
419 475
420 * manual reschedule mode ($reschedule_cb = coderef) 476 * manual reschedule mode ($reschedule_cb = coderef)
477
421 In this mode $interval and $at are both being ignored. Instead, 478 In this mode $interval and $at are both being ignored. Instead,
422 each time the periodic watcher gets scheduled, the reschedule 479 each time the periodic watcher gets scheduled, the reschedule
423 callback ($reschedule_cb) will be called with the watcher as 480 callback ($reschedule_cb) will be called with the watcher as
424 first, and the current time as second argument. 481 first, and the current time as second argument.
425 482
426 *This callback MUST NOT stop or destroy this or any other 483 *This callback MUST NOT stop or destroy this or any other
484 periodic watcher, ever, and MUST NOT call any event loop
427 periodic watcher, ever*. If you need to stop it, return 1e30 and 485 functions or methods*. If you need to stop it, return 1e30 and
428 stop it afterwards. 486 stop it afterwards. You may create and start a "EV::prepare"
487 watcher for this task.
429 488
430 It must return the next time to trigger, based on the passed 489 It must return the next time to trigger, based on the passed
431 time value (that is, the lowest time value larger than to the 490 time value (that is, the lowest time value larger than or equal
432 second argument). It will usually be called just before the 491 to to the second argument). It will usually be called just
433 callback will be triggered, but might be called at other times, 492 before the callback will be triggered, but might be called at
434 too. 493 other times, too.
435 494
436 This can be used to create very complex timers, such as a timer 495 This can be used to create very complex timers, such as a timer
437 that triggers on each midnight, local time (actually 24 hours 496 that triggers on each midnight, local time (actually 24 hours
438 after the last midnight, to keep the example simple. If you know 497 after the last midnight, to keep the example simple. If you know
439 a way to do it correctly in about the same space (without 498 a way to do it correctly in about the same space (without
… …
486 $old_signum = $w->signal ($new_signal) 545 $old_signum = $w->signal ($new_signal)
487 Returns the previously set signal (always as a number not name) and 546 Returns the previously set signal (always as a number not name) and
488 optionally set a new one. 547 optionally set a new one.
489 548
490 CHILD WATCHERS - watch out for process status changes 549 CHILD WATCHERS - watch out for process status changes
491 $w = EV::child $pid, $callback 550 $w = EV::child $pid, $trace, $callback
492 $w = EV::child_ns $pid, $callback 551 $w = EV::child_ns $pid, $trace, $callback
493 $w = $loop->child ($pid, $callback) 552 $w = $loop->child ($pid, $trace, $callback)
494 $w = $loop->child_ns ($pid, $callback) 553 $w = $loop->child_ns ($pid, $trace, $callback)
495 Call the callback when a status change for pid $pid (or any pid if 554 Call the callback when a status change for pid $pid (or any pid if
496 $pid is 0) has been received. More precisely: when the process 555 $pid is 0) has been received (a status change happens when the
556 process terminates or is killed, or, when trace is true,
557 additionally when it is stopped or continued). More precisely: when
497 receives a "SIGCHLD", EV will fetch the outstanding exit/wait status 558 the process receives a "SIGCHLD", EV will fetch the outstanding
498 for all changed/zombie children and call the callback. 559 exit/wait status for all changed/zombie children and call the
560 callback.
499 561
500 It is valid (and fully supported) to install a child watcher after a 562 It is valid (and fully supported) to install a child watcher after a
501 child has exited but before the event loop has started its next 563 child has exited but before the event loop has started its next
502 iteration (for example, first you "fork", then the new child process 564 iteration (for example, first you "fork", then the new child process
503 might exit, and only then do you install a child watcher in the 565 might exit, and only then do you install a child watcher in the
… …
510 be called. 572 be called.
511 573
512 The "child_ns" variant doesn't start (activate) the newly created 574 The "child_ns" variant doesn't start (activate) the newly created
513 watcher. 575 watcher.
514 576
515 $w->set ($pid) 577 $w->set ($pid, $trace)
516 Reconfigures the watcher, see the constructor above for details. Can 578 Reconfigures the watcher, see the constructor above for details. Can
517 be called at any time. 579 be called at any time.
518 580
519 $current_pid = $w->pid 581 $current_pid = $w->pid
520 $old_pid = $w->pid ($new_pid)
521 Returns the previously set process id and optionally set a new one. 582 Returns the previously set process id and optionally set a new one.
522 583
523 $exit_status = $w->rstatus 584 $exit_status = $w->rstatus
524 Return the exit/wait status (as returned by waitpid, see the waitpid 585 Return the exit/wait status (as returned by waitpid, see the waitpid
525 entry in perlfunc). 586 entry in perlfunc).
… …
708 process after a fork. 769 process after a fork.
709 770
710 The "fork_ns" variant doesn't start (activate) the newly created 771 The "fork_ns" variant doesn't start (activate) the newly created
711 watcher. 772 watcher.
712 773
774 EMBED WATCHERS - when one backend isn't enough...
775 This is a rather advanced watcher type that lets you embed one event
776 loop into another (currently only IO events are supported in the
777 embedded loop, other types of watchers might be handled in a delayed or
778 incorrect fashion and must not be used).
779
780 See the libev documentation at
781 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code
782 _when_one_backend_> (locally installed as EV::libev) for more details.
783
784 In short, this watcher is most useful on BSD systems without working
785 kqueue to still be able to handle a large number of sockets:
786
787 my $socket_loop;
788
789 # check wether we use SELECT or POLL _and_ KQUEUE is supported
790 if (
791 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
792 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
793 ) {
794 # use kqueue for sockets
795 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
796 }
797
798 # use the default loop otherwise
799 $socket_loop ||= EV::default_loop;
800
801 $w = EV::embed $otherloop[, $callback]
802 $w = EV::embed_ns $otherloop[, $callback]
803 $w = $loop->embed ($otherloop[, $callback])
804 $w = $loop->embed_ns ($otherloop[, $callback])
805 Call the callback when the embedded event loop ($otherloop) has any
806 I/O activity. The $callback is optional: if it is missing, then the
807 embedded event loop will be managed automatically (which is
808 recommended), otherwise you have to invoke "sweep" yourself.
809
810 The "embed_ns" variant doesn't start (activate) the newly created
811 watcher.
812
813 ASYNC WATCHERS - how to wake up another event loop
814 Async watchers are provided by EV, but have little use in perl directly,
815 as perl neither supports threads nor direct access to signal handlers or
816 other contexts where they could be of value.
817
818 It is, however, possible to use them from the XS level.
819
820 Please see the libev documentation for further details.
821
822 $w = EV::async $callback
823 $w = EV::async_ns $callback
824 $w->send
825 $bool = $w->async_pending
826
713PERL SIGNALS 827PERL SIGNALS
714 While Perl signal handling (%SIG) is not affected by EV, the behaviour 828 While Perl signal handling (%SIG) is not affected by EV, the behaviour
715 with EV is as the same as any other C library: Perl-signals will only be 829 with EV is as the same as any other C library: Perl-signals will only be
716 handled when Perl runs, which means your signal handler might be invoked 830 handled when Perl runs, which means your signal handler might be invoked
717 only the next time an event callback is invoked. 831 only the next time an event callback is invoked.
… …
751 course. 865 course.
752 866
753SEE ALSO 867SEE ALSO
754 EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event 868 EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event
755 loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines 869 loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines
756 with EV), Net::SNMP::EV (asynchronous SNMP). 870 with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop
871 agnostic and portable event driven programming.
757 872
758AUTHOR 873AUTHOR
759 Marc Lehmann <schmorp@schmorp.de> 874 Marc Lehmann <schmorp@schmorp.de>
760 http://home.schmorp.de/ 875 http://home.schmorp.de/
761 876

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