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| 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 | |
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|
| 24 | # IO |
23 | |
| 25 | |
24 | # IO |
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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 |
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63 | detailed information. |
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64 | |
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65 | This module is very fast and scalable. It is actually so fast that you |
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66 | can use it through the AnyEvent module, stay portable to other event |
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67 | loops (if you don't rely on any watcher types not available through it) |
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68 | and still be faster than with any other event loop currently supported |
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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 |
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| 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) |
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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, $reschedule_cb = 0) |
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434 | |
| 426 | In this mode the watcher will always be scheduled to time out at |
435 | In this mode the watcher will always be scheduled to time out at |
| 427 | the next "$at + N * $interval" time (for some integer N) and |
436 | the next "$at + N * $interval" time (for some integer N) and |
| 428 | then repeat, regardless of any time jumps. |
437 | then repeat, regardless of any time jumps. |
| 429 | |
438 | |
| 430 | This can be used to create timers that do not drift with respect |
439 | This can be used to create timers that do not drift with respect |
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… | |
| 439 | Another way to think about it (for the mathematically inclined) |
448 | Another way to think about it (for the mathematically inclined) |
| 440 | is that EV::periodic will try to run the callback in this mode |
449 | is that EV::periodic will try to run the callback in this mode |
| 441 | at the next possible time where "$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) |
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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 | |
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| 510 | $old_signum = $w->signal ($new_signal) |
520 | $old_signum = $w->signal ($new_signal) |
| 511 | Returns the previously set signal (always as a number not name) and |
521 | Returns the previously set signal (always as a number not name) and |
| 512 | optionally set a new one. |
522 | optionally set a new one. |
| 513 | |
523 | |
| 514 | CHILD WATCHERS - watch out for process status changes |
524 | CHILD WATCHERS - watch out for process status changes |
| 515 | $w = EV::child $pid, $callback |
525 | $w = EV::child $pid, $trace, $callback |
| 516 | $w = EV::child_ns $pid, $callback |
526 | $w = EV::child_ns $pid, $trace, $callback |
| 517 | $w = $loop->child ($pid, $callback) |
527 | $w = $loop->child ($pid, $trace, $callback) |
| 518 | $w = $loop->child_ns ($pid, $callback) |
528 | $w = $loop->child_ns ($pid, $trace, $callback) |
| 519 | Call the callback when a status change for pid $pid (or any pid if |
529 | 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 |
530 | $pid is 0) has been received (a status change happens when the |
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531 | process terminates or is killed, or, when trace is true, |
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532 | additionally when it is stopped or continued). More precisely: when |
| 521 | receives a "SIGCHLD", EV will fetch the outstanding exit/wait status |
533 | the process receives a "SIGCHLD", EV will fetch the outstanding |
| 522 | for all changed/zombie children and call the callback. |
534 | exit/wait status for all changed/zombie children and call the |
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535 | callback. |
| 523 | |
536 | |
| 524 | It is valid (and fully supported) to install a child watcher after a |
537 | 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 |
538 | child has exited but before the event loop has started its next |
| 526 | iteration (for example, first you "fork", then the new child process |
539 | 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 |
540 | might exit, and only then do you install a child watcher in the |
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| 534 | be called. |
547 | be called. |
| 535 | |
548 | |
| 536 | The "child_ns" variant doesn't start (activate) the newly created |
549 | The "child_ns" variant doesn't start (activate) the newly created |
| 537 | watcher. |
550 | watcher. |
| 538 | |
551 | |
| 539 | $w->set ($pid) |
552 | $w->set ($pid, $trace) |
| 540 | Reconfigures the watcher, see the constructor above for details. Can |
553 | Reconfigures the watcher, see the constructor above for details. Can |
| 541 | be called at any time. |
554 | be called at any time. |
| 542 | |
555 | |
| 543 | $current_pid = $w->pid |
556 | $current_pid = $w->pid |
| 544 | $old_pid = $w->pid ($new_pid) |
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| 545 | Returns the previously set process id and optionally set a new one. |
557 | Returns the previously set process id and optionally set a new one. |
| 546 | |
558 | |
| 547 | $exit_status = $w->rstatus |
559 | $exit_status = $w->rstatus |
| 548 | Return the exit/wait status (as returned by waitpid, see the waitpid |
560 | Return the exit/wait status (as returned by waitpid, see the waitpid |
| 549 | entry in perlfunc). |
561 | entry in perlfunc). |
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| 771 | managed automatically. |
783 | managed automatically. |
| 772 | |
784 | |
| 773 | The "embed_ns" variant doesn't start (activate) the newly created |
785 | The "embed_ns" variant doesn't start (activate) the newly created |
| 774 | watcher. |
786 | watcher. |
| 775 | |
787 | |
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788 | ASYNC WATCHERS - how to wake up another event loop |
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789 | Async watchers are provided by EV, but have little use in perl directly, |
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790 | as perl neither supports threads nor direct access to signal handlers or |
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791 | other contexts where they could be of value. |
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792 | |
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793 | It is, however, possible to use them from the XS level. |
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794 | |
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795 | Please see the libev documentation for further details. |
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796 | |
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797 | $w = EV::async $callback |
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798 | $w = EV::async_ns $callback |
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799 | $w->send |
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800 | $bool = $w->async_pending |
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801 | |
| 776 | PERL SIGNALS |
802 | PERL SIGNALS |
| 777 | While Perl signal handling (%SIG) is not affected by EV, the behaviour |
803 | 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 |
804 | 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 |
805 | handled when Perl runs, which means your signal handler might be invoked |
| 780 | only the next time an event callback is invoked. |
806 | only the next time an event callback is invoked. |
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| 814 | course. |
840 | course. |
| 815 | |
841 | |
| 816 | SEE ALSO |
842 | SEE ALSO |
| 817 | EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event |
843 | 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 |
844 | loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines |
| 819 | with EV), Net::SNMP::EV (asynchronous SNMP). |
845 | with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop |
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846 | agnostic and portable event driven programming. |
| 820 | |
847 | |
| 821 | AUTHOR |
848 | AUTHOR |
| 822 | Marc Lehmann <schmorp@schmorp.de> |
849 | Marc Lehmann <schmorp@schmorp.de> |
| 823 | http://home.schmorp.de/ |
850 | http://home.schmorp.de/ |
| 824 | |
851 | |
