… | |
… | |
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 | |
5 | SYNOPSIS |
5 | SYNOPSIS |
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 | |
|
|
24 | # IO |
23 | |
25 | |
24 | # IO |
|
|
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 | |
55 | DESCRIPTION |
55 | DESCRIPTION |
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 | |
64 | EVENT LOOPS |
71 | EVENT 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 |
… | |
… | |
414 | changed by explicit date -s or other means such as ntpd). It is also |
421 | changed by explicit date -s or other means such as ntpd). It is also |
415 | the most complex watcher type in EV. |
422 | the most complex watcher type in EV. |
416 | |
423 | |
417 | It has three distinct "modes": |
424 | It has three distinct "modes": |
418 | |
425 | |
419 | * absolute timer ($interval = $reschedule_cb = 0) |
426 | * absolute timer ($interval = $reschedule_cb = 0) |
|
|
427 | |
420 | This time simply fires at the wallclock time $at and doesn't |
428 | This time simply fires at the wallclock time $at and doesn't |
421 | repeat. It will not adjust when a time jump occurs, that is, if |
429 | repeat. It will not adjust when a time jump occurs, that is, if |
422 | it is to be run at January 1st 2011 then it will run when the |
430 | it is to be run at January 1st 2011 then it will run when the |
423 | system time reaches or surpasses this time. |
431 | system time reaches or surpasses this time. |
424 | |
432 | |
425 | * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) |
433 | * repeating interval timer ($interval > 0, $reschedule_cb = 0) |
|
|
434 | |
426 | In this mode the watcher will always be scheduled to time out at |
435 | In this mode the watcher will always be scheduled to time out at |
427 | the next "$at + N * $interval" time (for some integer N) and |
436 | the next "$at + N * $interval" time (for some integer N) and |
428 | then repeat, regardless of any time jumps. |
437 | then repeat, regardless of any time jumps. |
429 | |
438 | |
430 | This can be used to create timers that do not drift with respect |
439 | This can be used to create timers that do not drift with respect |
… | |
… | |
439 | Another way to think about it (for the mathematically inclined) |
448 | Another way to think about it (for the mathematically inclined) |
440 | is that EV::periodic will try to run the callback in this mode |
449 | is that EV::periodic will try to run the callback in this mode |
441 | at the next possible time where "$time = $at (mod $interval)", |
450 | at the next possible time where "$time = $at (mod $interval)", |
442 | regardless of any time jumps. |
451 | regardless of any time jumps. |
443 | |
452 | |
444 | * manual reschedule mode ($reschedule_cb = coderef) |
453 | * manual reschedule mode ($reschedule_cb = coderef) |
|
|
454 | |
445 | In this mode $interval and $at are both being ignored. Instead, |
455 | In this mode $interval and $at are both being ignored. Instead, |
446 | each time the periodic watcher gets scheduled, the reschedule |
456 | each time the periodic watcher gets scheduled, the reschedule |
447 | callback ($reschedule_cb) will be called with the watcher as |
457 | callback ($reschedule_cb) will be called with the watcher as |
448 | first, and the current time as second argument. |
458 | first, and the current time as second argument. |
449 | |
459 | |
450 | *This callback MUST NOT stop or destroy this or any other |
460 | *This callback MUST NOT stop or destroy this or any other |
|
|
461 | periodic watcher, ever, and MUST NOT call any event loop |
451 | periodic watcher, ever*. If you need to stop it, return 1e30 and |
462 | functions or methods*. If you need to stop it, return 1e30 and |
452 | stop it afterwards. |
463 | stop it afterwards. You may create and start a "EV::prepare" |
|
|
464 | watcher for this task. |
453 | |
465 | |
454 | It must return the next time to trigger, based on the passed |
466 | 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 |
467 | time value (that is, the lowest time value larger than or equal |
456 | second argument). It will usually be called just before the |
468 | to to the second argument). It will usually be called just |
457 | callback will be triggered, but might be called at other times, |
469 | before the callback will be triggered, but might be called at |
458 | too. |
470 | other times, too. |
459 | |
471 | |
460 | This can be used to create very complex timers, such as a timer |
472 | This can be used to create very complex timers, such as a timer |
461 | that triggers on each midnight, local time (actually 24 hours |
473 | that triggers on each midnight, local time (actually 24 hours |
462 | after the last midnight, to keep the example simple. If you know |
474 | 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 |
475 | a way to do it correctly in about the same space (without |
… | |
… | |
510 | $old_signum = $w->signal ($new_signal) |
522 | $old_signum = $w->signal ($new_signal) |
511 | Returns the previously set signal (always as a number not name) and |
523 | Returns the previously set signal (always as a number not name) and |
512 | optionally set a new one. |
524 | optionally set a new one. |
513 | |
525 | |
514 | CHILD WATCHERS - watch out for process status changes |
526 | CHILD WATCHERS - watch out for process status changes |
515 | $w = EV::child $pid, $callback |
527 | $w = EV::child $pid, $trace, $callback |
516 | $w = EV::child_ns $pid, $callback |
528 | $w = EV::child_ns $pid, $trace, $callback |
517 | $w = $loop->child ($pid, $callback) |
529 | $w = $loop->child ($pid, $trace, $callback) |
518 | $w = $loop->child_ns ($pid, $callback) |
530 | $w = $loop->child_ns ($pid, $trace, $callback) |
519 | Call the callback when a status change for pid $pid (or any pid if |
531 | 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 |
532 | $pid is 0) has been received (a status change happens when the |
|
|
533 | process terminates or is killed, or, when trace is true, |
|
|
534 | additionally when it is stopped or continued). More precisely: when |
521 | receives a "SIGCHLD", EV will fetch the outstanding exit/wait status |
535 | the process receives a "SIGCHLD", EV will fetch the outstanding |
522 | for all changed/zombie children and call the callback. |
536 | exit/wait status for all changed/zombie children and call the |
|
|
537 | callback. |
523 | |
538 | |
524 | It is valid (and fully supported) to install a child watcher after a |
539 | 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 |
540 | child has exited but before the event loop has started its next |
526 | iteration (for example, first you "fork", then the new child process |
541 | 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 |
542 | might exit, and only then do you install a child watcher in the |
… | |
… | |
534 | be called. |
549 | be called. |
535 | |
550 | |
536 | The "child_ns" variant doesn't start (activate) the newly created |
551 | The "child_ns" variant doesn't start (activate) the newly created |
537 | watcher. |
552 | watcher. |
538 | |
553 | |
539 | $w->set ($pid) |
554 | $w->set ($pid, $trace) |
540 | Reconfigures the watcher, see the constructor above for details. Can |
555 | Reconfigures the watcher, see the constructor above for details. Can |
541 | be called at any time. |
556 | be called at any time. |
542 | |
557 | |
543 | $current_pid = $w->pid |
558 | $current_pid = $w->pid |
544 | $old_pid = $w->pid ($new_pid) |
|
|
545 | Returns the previously set process id and optionally set a new one. |
559 | Returns the previously set process id and optionally set a new one. |
546 | |
560 | |
547 | $exit_status = $w->rstatus |
561 | $exit_status = $w->rstatus |
548 | Return the exit/wait status (as returned by waitpid, see the waitpid |
562 | Return the exit/wait status (as returned by waitpid, see the waitpid |
549 | entry in perlfunc). |
563 | entry in perlfunc). |
… | |
… | |
771 | managed automatically. |
785 | managed automatically. |
772 | |
786 | |
773 | The "embed_ns" variant doesn't start (activate) the newly created |
787 | The "embed_ns" variant doesn't start (activate) the newly created |
774 | watcher. |
788 | watcher. |
775 | |
789 | |
|
|
790 | ASYNC WATCHERS - how to wake up another event loop |
|
|
791 | Async watchers are provided by EV, but have little use in perl directly, |
|
|
792 | as perl neither supports threads nor direct access to signal handlers or |
|
|
793 | other contexts where they could be of value. |
|
|
794 | |
|
|
795 | It is, however, possible to use them from the XS level. |
|
|
796 | |
|
|
797 | Please see the libev documentation for further details. |
|
|
798 | |
|
|
799 | $w = EV::async $callback |
|
|
800 | $w = EV::async_ns $callback |
|
|
801 | $w->send |
|
|
802 | $bool = $w->async_pending |
|
|
803 | |
776 | PERL SIGNALS |
804 | PERL SIGNALS |
777 | While Perl signal handling (%SIG) is not affected by EV, the behaviour |
805 | 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 |
806 | 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 |
807 | handled when Perl runs, which means your signal handler might be invoked |
780 | only the next time an event callback is invoked. |
808 | only the next time an event callback is invoked. |
… | |
… | |
814 | course. |
842 | course. |
815 | |
843 | |
816 | SEE ALSO |
844 | SEE ALSO |
817 | EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event |
845 | 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 |
846 | loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines |
819 | with EV), Net::SNMP::EV (asynchronous SNMP). |
847 | with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop |
|
|
848 | agnostic and portable event driven programming. |
820 | |
849 | |
821 | AUTHOR |
850 | AUTHOR |
822 | Marc Lehmann <schmorp@schmorp.de> |
851 | Marc Lehmann <schmorp@schmorp.de> |
823 | http://home.schmorp.de/ |
852 | http://home.schmorp.de/ |
824 | |
853 | |