1 | NAME |
1 | NAME |
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 | |
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 | |
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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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 | |
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86 | If you want to take avdantage of kqueue (which often works properly for |
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87 | sockets only) even though the default loop doesn't enable it, you can |
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88 | *embed* a kqueue loop into the default loop: running the default loop |
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89 | will then also service the kqueue loop to some extent. See the example |
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90 | in the section about embed watchers for an example on how to achieve |
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91 | that. |
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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. |
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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). |
96 | |
110 | |
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111 | $loop->loop_verify |
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112 | Calls "ev_verify" to make internal consistency checks (for debugging |
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113 | libev) and abort the program if any data structures were found to be |
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114 | corrupted. |
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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 |
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118 | module already creates the default loop with default flags, |
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119 | specifying flags here will not have any effect unless you destroy |
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120 | the default loop first, which isn't supported. So in short: don't do |
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121 | it, and if you break it, you get to keep the pieces. |
99 | |
122 | |
100 | BASIC INTERFACE |
123 | BASIC 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 |
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201 | WATCHER OBJECTS |
224 | WATCHER 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. |
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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 = $w->loop |
324 | Return the loop that this watcher is attached to. |
347 | Return the loop that this watcher is attached to. |
325 | |
348 | |
326 | WATCHER TYPES |
349 | WATCHER TYPES |
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414 | changed by explicit date -s or other means such as ntpd). It is also |
437 | changed by explicit date -s or other means such as ntpd). It is also |
415 | the most complex watcher type in EV. |
438 | the most complex watcher type in EV. |
416 | |
439 | |
417 | It has three distinct "modes": |
440 | It has three distinct "modes": |
418 | |
441 | |
419 | * absolute timer ($interval = $reschedule_cb = 0) |
442 | * absolute timer ($interval = $reschedule_cb = 0) |
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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, $reschedule_cb = 0) |
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450 | |
426 | In this mode the watcher will always be scheduled to time out at |
451 | In this mode the watcher will always be scheduled to time out at |
427 | the next "$at + N * $interval" time (for some integer N) and |
452 | the next "$at + N * $interval" time (for some integer N) and |
428 | then repeat, regardless of any time jumps. |
453 | then repeat, regardless of any time jumps. |
429 | |
454 | |
430 | This can be used to create timers that do not drift with respect |
455 | This can be used to create timers that do not drift with respect |
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439 | Another way to think about it (for the mathematically inclined) |
464 | Another way to think about it (for the mathematically inclined) |
440 | is that EV::periodic will try to run the callback in this mode |
465 | is that EV::periodic will try to run the callback in this mode |
441 | at the next possible time where "$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) |
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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 |
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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" |
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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 |
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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 |
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549 | process terminates or is killed, or, when trace is true, |
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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 |
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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 |
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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) |
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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). |
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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) |
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771 | managed automatically. |
801 | managed automatically. |
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. |
775 | |
805 | |
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806 | ASYNC WATCHERS - how to wake up another event loop |
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807 | Async watchers are provided by EV, but have little use in perl directly, |
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808 | as perl neither supports threads nor direct access to signal handlers or |
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809 | other contexts where they could be of value. |
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810 | |
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811 | It is, however, possible to use them from the XS level. |
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812 | |
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813 | Please see the libev documentation for further details. |
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814 | |
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815 | $w = EV::async $callback |
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816 | $w = EV::async_ns $callback |
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817 | $w->send |
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818 | $bool = $w->async_pending |
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819 | |
776 | PERL SIGNALS |
820 | PERL 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 |
780 | only the next time an event callback is invoked. |
824 | only the next time an event callback is invoked. |
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814 | course. |
858 | course. |
815 | |
859 | |
816 | SEE ALSO |
860 | SEE 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 |
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864 | agnostic and portable event driven programming. |
820 | |
865 | |
821 | AUTHOR |
866 | AUTHOR |
822 | Marc Lehmann <schmorp@schmorp.de> |
867 | Marc Lehmann <schmorp@schmorp.de> |
823 | http://home.schmorp.de/ |
868 | http://home.schmorp.de/ |
824 | |
869 | |