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Revision 1.21 by root, Sat Dec 22 16:48:33 2007 UTC vs.
Revision 1.29 by root, Sat Jul 12 22:19:22 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
… …
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 can create additional event loops dynamically. 84 For specific programs you can create additional event loops dynamically.
78 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.
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
83 ONS>) for more info. 97 ONS>) for more info.
… …
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).
96 110
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
97 $loop = EV::default_loop [$flags] 116 $loop = EV::default_loop [$flags]
98 Return the default loop (which is a singleton object). 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.
99 122
100BASIC INTERFACE 123BASIC INTERFACE
101 $EV::DIED 124 $EV::DIED
102 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
103 callback throws an exception (with $@ containing the error). The 126 callback throws an exception (with $@ containing the error). The
… …
201WATCHER OBJECTS 224WATCHER OBJECTS
202 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
203 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,
204 you would create an EV::io watcher for that: 227 you would create an EV::io watcher for that:
205 228
206 my $watcher = EV::io *STDIN, EV::READ, sub { 229 my $watcher = EV::io *STDIN, EV::READ, sub {
207 my ($watcher, $revents) = @_; 230 my ($watcher, $revents) = @_;
208 warn "yeah, STDIN should now be readable without blocking!\n" 231 warn "yeah, STDIN should now be readable without blocking!\n"
209 }; 232 };
210 233
211 All watchers can be active (waiting for events) or inactive (paused). 234 All watchers can be active (waiting for events) or inactive (paused).
212 Only active watchers will have their callbacks invoked. All callbacks 235 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 236 will be called with at least two arguments: the watcher and a bitmask of
214 received events. 237 received events.
… …
316 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
317 the event loop from running just because of that watcher. 340 the event loop from running just because of that watcher.
318 341
319 my $udp_socket = ... 342 my $udp_socket = ...
320 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 343 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
321 $1000udp_watcher->keepalive (0); 344 $udp_watcher->keepalive (0);
322 345
323 $loop = $w->loop 346 $loop = $w->loop
324 Return the loop that this watcher is attached to. 347 Return the loop that this watcher is attached to.
325 348
326WATCHER TYPES 349WATCHER TYPES
… …
414 changed by explicit date -s or other means such as ntpd). It is also 437 changed by explicit date -s or other means such as ntpd). It is also
415 the most complex watcher type in EV. 438 the most complex watcher type in EV.
416 439
417 It has three distinct "modes": 440 It has three distinct "modes":
418 441
419 * absolute timer ($interval = $reschedule_cb = 0) 442 * absolute timer ($interval = $reschedule_cb = 0)
443
420 This time simply fires at the wallclock time $at and doesn't 444 This time simply fires at the wallclock time $at and doesn't
421 repeat. It will not adjust when a time jump occurs, that is, if 445 repeat. It will not adjust when a time jump occurs, that is, if
422 it is to be run at January 1st 2011 then it will run when the 446 it is to be run at January 1st 2011 then it will run when the
423 system time reaches or surpasses this time. 447 system time reaches or surpasses this time.
424 448
425 * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 449 * repeating interval timer ($interval > 0, $reschedule_cb = 0)
450
426 In this mode the watcher will always be scheduled to time out at 451 In this mode the watcher will always be scheduled to time out at
427 the next "$at + N * $interval" time (for some integer N) and 452 the next "$at + N * $interval" time (for some integer N) and
428 then repeat, regardless of any time jumps. 453 then repeat, regardless of any time jumps.
429 454
430 This can be used to create timers that do not drift with respect 455 This can be used to create timers that do not drift with respect
… …
439 Another way to think about it (for the mathematically inclined) 464 Another way to think about it (for the mathematically inclined)
440 is that EV::periodic will try to run the callback in this mode 465 is that EV::periodic will try to run the callback in this mode
441 at the next possible time where "$time = $at (mod $interval)", 466 at the next possible time where "$time = $at (mod $interval)",
442 regardless of any time jumps. 467 regardless of any time jumps.
443 468
444 * manual reschedule mode ($reschedule_cb = coderef) 469 * manual reschedule mode ($reschedule_cb = coderef)
470
445 In this mode $interval and $at are both being ignored. Instead, 471 In this mode $interval and $at are both being ignored. Instead,
446 each time the periodic watcher gets scheduled, the reschedule 472 each time the periodic watcher gets scheduled, the reschedule
447 callback ($reschedule_cb) will be called with the watcher as 473 callback ($reschedule_cb) will be called with the watcher as
448 first, and the current time as second argument. 474 first, and the current time as second argument.
449 475
450 *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
451 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
452 stop it afterwards. 479 stop it afterwards. You may create and start a "EV::prepare"
480 watcher for this task.
453 481
454 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
455 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
456 second argument). It will usually be called just before the 484 to to the second argument). It will usually be called just
457 callback will be triggered, but might be called at other times, 485 before the callback will be triggered, but might be called at
458 too. 486 other times, too.
459 487
460 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
461 that triggers on each midnight, local time (actually 24 hours 489 that triggers on each midnight, local time (actually 24 hours
462 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
463 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
… …
510 $old_signum = $w->signal ($new_signal) 538 $old_signum = $w->signal ($new_signal)
511 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
512 optionally set a new one. 540 optionally set a new one.
513 541
514 CHILD WATCHERS - watch out for process status changes 542 CHILD WATCHERS - watch out for process status changes
515 $w = EV::child $pid, $callback 543 $w = EV::child $pid, $trace, $callback
516 $w = EV::child_ns $pid, $callback 544 $w = EV::child_ns $pid, $trace, $callback
517 $w = $loop->child ($pid, $callback) 545 $w = $loop->child ($pid, $trace, $callback)
518 $w = $loop->child_ns ($pid, $callback) 546 $w = $loop->child_ns ($pid, $trace, $callback)
519 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
520 $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
521 receives a "SIGCHLD", EV will fetch the outstanding exit/wait status 551 the process receives a "SIGCHLD", EV will fetch the outstanding
522 for all changed/zombie children and call the callback. 552 exit/wait status for all changed/zombie children and call the
553 callback.
523 554
524 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
525 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
526 iteration (for example, first you "fork", then the new child process 557 iteration (for example, first you "fork", then the new child process
527 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
… …
534 be called. 565 be called.
535 566
536 The "child_ns" variant doesn't start (activate) the newly created 567 The "child_ns" variant doesn't start (activate) the newly created
537 watcher. 568 watcher.
538 569
539 $w->set ($pid) 570 $w->set ($pid, $trace)
540 Reconfigures the watcher, see the constructor above for details. Can 571 Reconfigures the watcher, see the constructor above for details. Can
541 be called at any time. 572 be called at any time.
542 573
543 $current_pid = $w->pid 574 $current_pid = $w->pid
544 $old_pid = $w->pid ($new_pid)
545 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.
546 576
547 $exit_status = $w->rstatus 577 $exit_status = $w->rstatus
548 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
549 entry in perlfunc). 579 entry in perlfunc).
… …
745 _when_one_backend_> for more details. 775 _when_one_backend_> for more details.
746 776
747 In short, this watcher is most useful on BSD systems without working 777 In short, this watcher is most useful on BSD systems without working
748 kqueue to still be able to handle a large number of sockets: 778 kqueue to still be able to handle a large number of sockets:
749 779
750 my $socket_loop; 780 my $socket_loop;
751 781
752 # check wether we use SELECT or POLL _and_ KQUEUE is supported 782 # check wether we use SELECT or POLL _and_ KQUEUE is supported
753 if ( 783 if (
754 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 784 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
755 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 785 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
756 ) { 786 ) {
757 # use kqueue for sockets 787 # use kqueue for sockets
758 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 788 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
759 } 789 }
760 790
761 # use the default loop otherwise 791 # use the default loop otherwise
762 $socket_loop ||= EV::default_loop; 792 $socket_loop ||= EV::default_loop;
763 793
764 $w = EV::embed $otherloop, $callback 794 $w = EV::embed $otherloop[, $callback]
765 $w = EV::embed_ns $otherloop, $callback 795 $w = EV::embed_ns $otherloop[, $callback]
766 $w = $loop->embed ($otherloop, $callback) 796 $w = $loop->embed ($otherloop[, $callback])
767 $w = $loop->embed_ns ($otherloop, $callback) 797 $w = $loop->embed_ns ($otherloop[, $callback])
768 Call the callback when the embedded event loop ($otherloop) has any 798 Call the callback when the embedded event loop ($otherloop) has any
769 I/O activity. The $callback should alwas be specified as "undef" in 799 I/O activity. The $callback is optional: if it is missing, then the
770 this version of EV, which means the embedded event loop will be 800 embedded event loop will be managed automatically (which is
771 managed automatically. 801 recommended), otherwise you have to invoke "sweep" yourself.
772 802
773 The "embed_ns" variant doesn't start (activate) the newly created 803 The "embed_ns" variant doesn't start (activate) the newly created
774 watcher. 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
775 819
776PERL SIGNALS 820PERL SIGNALS
777 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
778 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
779 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
… …
814 course. 858 course.
815 859
816SEE ALSO 860SEE ALSO
817 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
818 loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines 862 loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines
819 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.
820 865
821AUTHOR 866AUTHOR
822 Marc Lehmann <schmorp@schmorp.de> 867 Marc Lehmann <schmorp@schmorp.de>
823 http://home.schmorp.de/ 868 http://home.schmorp.de/
824 869

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