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Revision 1.28 by root, Tue Jul 8 18:56:48 2008 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 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>)
60 details on watcher semantics or some discussion on the available 60 for more subtle details on watcher semantics or some discussion on the
61 backends, or how to force a specific backend with "LIBEV_FLAGS", or just 61 available backends, or how to force a specific backend with
62 about in any case because it has much more detailed information. 62 "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.
63 70
64EVENT LOOPS 71EVENT LOOPS
65 EV supports multiple event loops: There is a single "default event loop" 72 EV supports multiple event loops: There is a single "default event loop"
66 that can handle everything including signals and child watchers, and any 73 that can handle everything including signals and child watchers, and any
67 number of "dynamic event loops" that can use different backends (with 74 number of "dynamic event loops" that can use different backends (with
… …
72 selecting a working backend (which for example rules out kqueue on most 79 selecting a working backend (which for example rules out kqueue on most
73 BSDs). Modules should, unless they have "special needs" always use the 80 BSDs). Modules should, unless they have "special needs" always use the
74 default loop as this is fastest (perl-wise), best supported by other 81 default loop as this is fastest (perl-wise), best supported by other
75 modules (e.g. AnyEvent or Coro) and most portable event loop. 82 modules (e.g. AnyEvent or Coro) and most portable event loop.
76 83
77 For specific programs you cna create additional event loops dynamically. 84 For specific programs you can create additional event loops dynamically.
85
86 If you want to take avdantage of kqueue (which often works properly for
87 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
89 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
91 that.
78 92
79 $loop = new EV::loop [$flags] 93 $loop = new EV::loop [$flags]
80 Create a new event loop as per the specified flags. Please refer to 94 Create a new event loop as per the specified flags. Please refer to
81 the "ev_loop_new ()" function description in the libev documentation 95 the "ev_loop_new ()" function description in the libev documentation
82 (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI 96 (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI
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89 loop is protected by this module. 103 loop is protected by this module.
90 104
91 $loop->loop_fork 105 $loop->loop_fork
92 Must be called after a fork in the child, before entering or 106 Must be called after a fork in the child, before entering or
93 continuing the event loop. An alternative is to use 107 continuing the event loop. An alternative is to use
94 "EV::FLAG_FORKCHECK" which calls this fucntion automatically, at 108 "EV::FLAG_FORKCHECK" which calls this function automatically, at
95 some performance loss (refer to the libev documentation). 109 some performance loss (refer to the libev documentation).
110
111 $loop->loop_verify
112 Calls "ev_verify" to make internal consistency checks (for debugging
113 libev) and abort the program if any data structures were found to be
114 corrupted.
115
116 $loop = EV::default_loop [$flags]
117 Return the default loop (which is a singleton object). Since this
118 module already creates the default loop with default flags,
119 specifying flags here will not have any effect unless you destroy
120 the default loop first, which isn't supported. So in short: don't do
121 it, and if you break it, you get to keep the pieces.
96 122
97BASIC INTERFACE 123BASIC INTERFACE
98 $EV::DIED 124 $EV::DIED
99 Must contain a reference to a function that is called when a 125 Must contain a reference to a function that is called when a
100 callback throws an exception (with $@ containing the error). The 126 callback throws an exception (with $@ containing the error). The
101 default prints an informative message and continues. 127 default prints an informative message and continues.
102 128
103 If this callback throws an exception it will be silently ignored. 129 If this callback throws an exception it will be silently ignored.
130
131 $flags = EV::supported_backends
132 $flags = EV::recommended_backends
133 $flags = EV::embeddable_backends
134 Returns the set (see "EV::BACKEND_*" flags) of backends supported by
135 this instance of EV, the set of recommended backends (supposed to be
136 good) for this platform and the set of embeddable backends (see
137 EMBED WATCHERS).
138
139 EV::sleep $seconds
140 Block the process for the given number of (fractional) seconds.
104 141
105 $time = EV::time 142 $time = EV::time
106 Returns the current time in (fractional) seconds since the epoch. 143 Returns the current time in (fractional) seconds since the epoch.
107 144
108 $time = EV::now 145 $time = EV::now
… …
172 209
173 EV::feed_signal_event ($signal) 210 EV::feed_signal_event ($signal)
174 Feed a signal event into EV. EV will react to this call as if the 211 Feed a signal event into EV. EV will react to this call as if the
175 signal specified by $signal had occured. 212 signal specified by $signal had occured.
176 213
214 EV::set_io_collect_interval $time
215 $loop->set_io_collect_interval ($time)
216 EV::set_timeout_collect_interval $time
217 $loop->set_timeout_collect_interval ($time)
218 These advanced functions set the minimum block interval when polling
219 for I/O events and the minimum wait interval for timer events. See
220 the libev documentation at
221 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT
222 ROLLING_THE_EVENT_LOOP> for a more detailed discussion.
223
177WATCHER OBJECTS 224WATCHER OBJECTS
178 A watcher is an object that gets created to record your interest in some 225 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, 226 event. For instance, if you want to wait for STDIN to become readable,
180 you would create an EV::io watcher for that: 227 you would create an EV::io watcher for that:
181 228
182 my $watcher = EV::io *STDIN, EV::READ, sub { 229 my $watcher = EV::io *STDIN, EV::READ, sub {
183 my ($watcher, $revents) = @_; 230 my ($watcher, $revents) = @_;
184 warn "yeah, STDIN should now be readable without blocking!\n" 231 warn "yeah, STDIN should now be readable without blocking!\n"
185 }; 232 };
186 233
187 All watchers can be active (waiting for events) or inactive (paused). 234 All watchers can be active (waiting for events) or inactive (paused).
188 Only active watchers will have their callbacks invoked. All callbacks 235 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 236 will be called with at least two arguments: the watcher and a bitmask of
190 received events. 237 received events.
… …
292 Example: Register an I/O watcher for some UDP socket but do not keep 339 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. 340 the event loop from running just because of that watcher.
294 341
295 my $udp_socket = ... 342 my $udp_socket = ...
296 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 343 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
297 $1000udp_watcher->keepalive (0); 344 $udp_watcher->keepalive (0);
298 345
299 $loop = $w->loop 346 $loop = $w->loop
300 Return the loop that this watcher is attached to. 347 Return the loop that this watcher is attached to.
301 348
302WATCHER TYPES 349WATCHER TYPES
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390 changed by explicit date -s or other means such as ntpd). It is also 437 changed by explicit date -s or other means such as ntpd). It is also
391 the most complex watcher type in EV. 438 the most complex watcher type in EV.
392 439
393 It has three distinct "modes": 440 It has three distinct "modes":
394 441
395 * absolute timer ($interval = $reschedule_cb = 0) 442 * absolute timer ($interval = $reschedule_cb = 0)
443
396 This time simply fires at the wallclock time $at and doesn't 444 This time simply fires at the wallclock time $at and doesn't
397 repeat. It will not adjust when a time jump occurs, that is, if 445 repeat. It will not adjust when a time jump occurs, that is, if
398 it is to be run at January 1st 2011 then it will run when the 446 it is to be run at January 1st 2011 then it will run when the
399 system time reaches or surpasses this time. 447 system time reaches or surpasses this time.
400 448
401 * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 449 * repeating interval timer ($interval > 0, $reschedule_cb = 0)
450
402 In this mode the watcher will always be scheduled to time out at 451 In this mode the watcher will always be scheduled to time out at
403 the next "$at + N * $interval" time (for some integer N) and 452 the next "$at + N * $interval" time (for some integer N) and
404 then repeat, regardless of any time jumps. 453 then repeat, regardless of any time jumps.
405 454
406 This can be used to create timers that do not drift with respect 455 This can be used to create timers that do not drift with respect
… …
415 Another way to think about it (for the mathematically inclined) 464 Another way to think about it (for the mathematically inclined)
416 is that EV::periodic will try to run the callback in this mode 465 is that EV::periodic will try to run the callback in this mode
417 at the next possible time where "$time = $at (mod $interval)", 466 at the next possible time where "$time = $at (mod $interval)",
418 regardless of any time jumps. 467 regardless of any time jumps.
419 468
420 * manual reschedule mode ($reschedule_cb = coderef) 469 * manual reschedule mode ($reschedule_cb = coderef)
470
421 In this mode $interval and $at are both being ignored. Instead, 471 In this mode $interval and $at are both being ignored. Instead,
422 each time the periodic watcher gets scheduled, the reschedule 472 each time the periodic watcher gets scheduled, the reschedule
423 callback ($reschedule_cb) will be called with the watcher as 473 callback ($reschedule_cb) will be called with the watcher as
424 first, and the current time as second argument. 474 first, and the current time as second argument.
425 475
426 *This callback MUST NOT stop or destroy this or any other 476 *This callback MUST NOT stop or destroy this or any other
477 periodic watcher, ever, and MUST NOT call any event loop
427 periodic watcher, ever*. If you need to stop it, return 1e30 and 478 functions or methods*. If you need to stop it, return 1e30 and
428 stop it afterwards. 479 stop it afterwards. You may create and start a "EV::prepare"
480 watcher for this task.
429 481
430 It must return the next time to trigger, based on the passed 482 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 483 time value (that is, the lowest time value larger than or equal
432 second argument). It will usually be called just before the 484 to to the second argument). It will usually be called just
433 callback will be triggered, but might be called at other times, 485 before the callback will be triggered, but might be called at
434 too. 486 other times, too.
435 487
436 This can be used to create very complex timers, such as a timer 488 This can be used to create very complex timers, such as a timer
437 that triggers on each midnight, local time (actually 24 hours 489 that triggers on each midnight, local time (actually 24 hours
438 after the last midnight, to keep the example simple. If you know 490 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 491 a way to do it correctly in about the same space (without
… …
486 $old_signum = $w->signal ($new_signal) 538 $old_signum = $w->signal ($new_signal)
487 Returns the previously set signal (always as a number not name) and 539 Returns the previously set signal (always as a number not name) and
488 optionally set a new one. 540 optionally set a new one.
489 541
490 CHILD WATCHERS - watch out for process status changes 542 CHILD WATCHERS - watch out for process status changes
491 $w = EV::child $pid, $callback 543 $w = EV::child $pid, $trace, $callback
492 $w = EV::child_ns $pid, $callback 544 $w = EV::child_ns $pid, $trace, $callback
493 $w = $loop->child ($pid, $callback) 545 $w = $loop->child ($pid, $trace, $callback)
494 $w = $loop->child_ns ($pid, $callback) 546 $w = $loop->child_ns ($pid, $trace, $callback)
495 Call the callback when a status change for pid $pid (or any pid if 547 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 548 $pid is 0) has been received (a status change happens when the
549 process terminates or is killed, or, when trace is true,
550 additionally when it is stopped or continued). More precisely: when
497 receives a "SIGCHLD", EV will fetch the outstanding exit/wait status 551 the process receives a "SIGCHLD", EV will fetch the outstanding
498 for all changed/zombie children and call the callback. 552 exit/wait status for all changed/zombie children and call the
553 callback.
499 554
500 It is valid (and fully supported) to install a child watcher after a 555 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 556 child has exited but before the event loop has started its next
502 iteration (for example, first you "fork", then the new child process 557 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 558 might exit, and only then do you install a child watcher in the
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510 be called. 565 be called.
511 566
512 The "child_ns" variant doesn't start (activate) the newly created 567 The "child_ns" variant doesn't start (activate) the newly created
513 watcher. 568 watcher.
514 569
515 $w->set ($pid) 570 $w->set ($pid, $trace)
516 Reconfigures the watcher, see the constructor above for details. Can 571 Reconfigures the watcher, see the constructor above for details. Can
517 be called at any time. 572 be called at any time.
518 573
519 $current_pid = $w->pid 574 $current_pid = $w->pid
520 $old_pid = $w->pid ($new_pid)
521 Returns the previously set process id and optionally set a new one. 575 Returns the previously set process id and optionally set a new one.
522 576
523 $exit_status = $w->rstatus 577 $exit_status = $w->rstatus
524 Return the exit/wait status (as returned by waitpid, see the waitpid 578 Return the exit/wait status (as returned by waitpid, see the waitpid
525 entry in perlfunc). 579 entry in perlfunc).
… …
708 process after a fork. 762 process after a fork.
709 763
710 The "fork_ns" variant doesn't start (activate) the newly created 764 The "fork_ns" variant doesn't start (activate) the newly created
711 watcher. 765 watcher.
712 766
767 EMBED WATCHERS - when one backend isn't enough...
768 This is a rather advanced watcher type that lets you embed one event
769 loop into another (currently only IO events are supported in the
770 embedded loop, other types of watchers might be handled in a delayed or
771 incorrect fashion and must not be used).
772
773 See the libev documentation at
774 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code
775 _when_one_backend_> for more details.
776
777 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:
779
780 my $socket_loop;
781
782 # check wether we use SELECT or POLL _and_ KQUEUE is supported
783 if (
784 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
785 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
786 ) {
787 # use kqueue for sockets
788 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
789 }
790
791 # use the default loop otherwise
792 $socket_loop ||= EV::default_loop;
793
794 $w = EV::embed $otherloop, $callback
795 $w = EV::embed_ns $otherloop, $callback
796 $w = $loop->embed ($otherloop, $callback)
797 $w = $loop->embed_ns ($otherloop, $callback)
798 Call the callback when the embedded event loop ($otherloop) has any
799 I/O activity. The $callback should alwas be specified as "undef" in
800 this version of EV, which means the embedded event loop will be
801 managed automatically.
802
803 The "embed_ns" variant doesn't start (activate) the newly created
804 watcher.
805
806 ASYNC WATCHERS - how to wake up another event loop
807 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
809 other contexts where they could be of value.
810
811 It is, however, possible to use them from the XS level.
812
813 Please see the libev documentation for further details.
814
815 $w = EV::async $callback
816 $w = EV::async_ns $callback
817 $w->send
818 $bool = $w->async_pending
819
713PERL SIGNALS 820PERL SIGNALS
714 While Perl signal handling (%SIG) is not affected by EV, the behaviour 821 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 822 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 823 handled when Perl runs, which means your signal handler might be invoked
717 only the next time an event callback is invoked. 824 only the next time an event callback is invoked.
… …
751 course. 858 course.
752 859
753SEE ALSO 860SEE ALSO
754 EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event 861 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 862 loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines
756 with EV), Net::SNMP::EV (asynchronous SNMP). 863 with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop
864 agnostic and portable event driven programming.
757 865
758AUTHOR 866AUTHOR
759 Marc Lehmann <schmorp@schmorp.de> 867 Marc Lehmann <schmorp@schmorp.de>
760 http://home.schmorp.de/ 868 http://home.schmorp.de/
761 869

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