… | |
… | |
46 | EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled |
46 | EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled |
47 | EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block |
47 | EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block |
48 | |
48 | |
49 | DESCRIPTION |
49 | DESCRIPTION |
50 | This module provides an interface to libev |
50 | This module provides an interface to libev |
51 | (<http://software.schmorp.de/pkg/libev.html>). |
51 | (<http://software.schmorp.de/pkg/libev.html>). While the documentation |
|
|
52 | below is comprehensive, one might also consult the documentation of |
|
|
53 | libev itself (<http://cvs.schmorp.de/libev/ev.html>) for more subtle |
|
|
54 | details on watcher semantics or some discussion on the available |
|
|
55 | backends, or how to force a specific backend with "LIBEV_FLAGS". |
52 | |
56 | |
53 | BASIC INTERFACE |
57 | BASIC INTERFACE |
54 | $EV::DIED |
58 | $EV::DIED |
55 | Must contain a reference to a function that is called when a |
59 | Must contain a reference to a function that is called when a |
56 | callback throws an exception (with $@ containing thr error). The |
60 | callback throws an exception (with $@ containing thr error). The |
… | |
… | |
84 | When called with no arguments or an argument of EV::UNLOOP_ONE, |
88 | When called with no arguments or an argument of EV::UNLOOP_ONE, |
85 | makes the innermost call to EV::loop return. |
89 | makes the innermost call to EV::loop return. |
86 | |
90 | |
87 | When called with an argument of EV::UNLOOP_ALL, all calls to |
91 | When called with an argument of EV::UNLOOP_ALL, all calls to |
88 | EV::loop will return as fast as possible. |
92 | EV::loop will return as fast as possible. |
|
|
93 | |
|
|
94 | EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
|
|
95 | This function rolls together an I/O and a timer watcher for a single |
|
|
96 | one-shot event without the need for managing a watcher object. |
|
|
97 | |
|
|
98 | If $fh_or_undef is a filehandle or file descriptor, then $events |
|
|
99 | must be a bitset containing either "EV::READ", "EV::WRITE" or |
|
|
100 | "EV::READ | EV::WRITE", indicating the type of I/O event you want to |
|
|
101 | wait for. If you do not want to wait for some I/O event, specify |
|
|
102 | "undef" for $fh_or_undef and 0 for $events). |
|
|
103 | |
|
|
104 | If timeout is "undef" or negative, then there will be no timeout. |
|
|
105 | Otherwise a EV::timer with this value will be started. |
|
|
106 | |
|
|
107 | When an error occurs or either the timeout or I/O watcher triggers, |
|
|
108 | then the callback will be called with the received event set (in |
|
|
109 | general you can expect it to be a combination of "EV:ERROR", |
|
|
110 | "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). |
|
|
111 | |
|
|
112 | EV::once doesn't return anything: the watchers stay active till |
|
|
113 | either of them triggers, then they will be stopped and freed, and |
|
|
114 | the callback invoked. |
89 | |
115 | |
90 | WATCHER |
116 | WATCHER |
91 | A watcher is an object that gets created to record your interest in some |
117 | A watcher is an object that gets created to record your interest in some |
92 | event. For instance, if you want to wait for STDIN to become readable, |
118 | event. For instance, if you want to wait for STDIN to become readable, |
93 | you would create an EV::io watcher for that: |
119 | you would create an EV::io watcher for that: |
… | |
… | |
165 | Pending watchers with higher priority will be invoked first. The |
191 | Pending watchers with higher priority will be invoked first. The |
166 | valid range of priorities lies between EV::MAXPRI (default 2) and |
192 | valid range of priorities lies between EV::MAXPRI (default 2) and |
167 | EV::MINPRI (default -2). If the priority is outside this range it |
193 | EV::MINPRI (default -2). If the priority is outside this range it |
168 | will automatically be normalised to the nearest valid priority. |
194 | will automatically be normalised to the nearest valid priority. |
169 | |
195 | |
170 | The default priority of any newly-created weatcher is 0. |
196 | The default priority of any newly-created watcher is 0. |
|
|
197 | |
|
|
198 | Note that the priority semantics have not yet been fleshed out and |
|
|
199 | are subject to almost certain change. |
171 | |
200 | |
172 | $w->trigger ($revents) |
201 | $w->trigger ($revents) |
173 | Call the callback *now* with the given event mask. |
202 | Call the callback *now* with the given event mask. |
|
|
203 | |
|
|
204 | $previous_state = $w->keepalive ($bool) |
|
|
205 | Normally, "EV::loop" will return when there are no active watchers |
|
|
206 | (which is a "deadlock" because no progress can be made anymore). |
|
|
207 | This is convinient because it allows you to start your watchers (and |
|
|
208 | your jobs), call "EV::loop" once and when it returns you know that |
|
|
209 | all your jobs are finished (or they forgot to register some watchers |
|
|
210 | for their task :). |
|
|
211 | |
|
|
212 | Sometimes, however, this gets in your way, for example when you the |
|
|
213 | module that calls "EV::loop" (usually the main program) is not the |
|
|
214 | same module as a long-living watcher (for example a DNS client |
|
|
215 | module written by somebody else even). Then you might want any |
|
|
216 | outstanding requests to be handled, but you would not want to keep |
|
|
217 | "EV::loop" from returning just because you happen to have this |
|
|
218 | long-running UDP port watcher. |
|
|
219 | |
|
|
220 | In this case you can clear the keepalive status, which means that |
|
|
221 | even though your watcher is active, it won't keep "EV::loop" from |
|
|
222 | returning. |
|
|
223 | |
|
|
224 | The initial value for keepalive is true (enabled), and you cna |
|
|
225 | change it any time. |
|
|
226 | |
|
|
227 | Example: Register an IO watcher for some UDP socket but do not keep |
|
|
228 | the event loop from running just because of that watcher. |
|
|
229 | |
|
|
230 | my $udp_socket = ... |
|
|
231 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
|
|
232 | $udp_watcher->keepalive (0); |
174 | |
233 | |
175 | $w = EV::io $fileno_or_fh, $eventmask, $callback |
234 | $w = EV::io $fileno_or_fh, $eventmask, $callback |
176 | $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
235 | $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
177 | As long as the returned watcher object is alive, call the $callback |
236 | As long as the returned watcher object is alive, call the $callback |
178 | when the events specified in $eventmask. |
237 | when the events specified in $eventmask. |
… | |
… | |
197 | $old_eventmask = $w->events ($new_eventmask) |
256 | $old_eventmask = $w->events ($new_eventmask) |
198 | Returns the previously set event mask and optionally set a new one. |
257 | Returns the previously set event mask and optionally set a new one. |
199 | |
258 | |
200 | $w = EV::timer $after, $repeat, $callback |
259 | $w = EV::timer $after, $repeat, $callback |
201 | $w = EV::timer_ns $after, $repeat, $callback |
260 | $w = EV::timer_ns $after, $repeat, $callback |
202 | Calls the callback after $after seconds. If $repeat is non-zero, the |
261 | Calls the callback after $after seconds (which may be fractional). |
203 | timer will be restarted (with the $repeat value as $after) after the |
262 | If $repeat is non-zero, the timer will be restarted (with the |
204 | callback returns. |
263 | $repeat value as $after) after the callback returns. |
205 | |
264 | |
206 | This means that the callback would be called roughly after $after |
265 | This means that the callback would be called roughly after $after |
207 | seconds, and then every $repeat seconds. The timer does his best not |
266 | seconds, and then every $repeat seconds. The timer does his best not |
208 | to drift, but it will not invoke the timer more often then once per |
267 | to drift, but it will not invoke the timer more often then once per |
209 | event loop iteration, and might drift in other cases. If that isn't |
268 | event loop iteration, and might drift in other cases. If that isn't |
… | |
… | |
414 | # do nothing unless active |
473 | # do nothing unless active |
415 | $dispatcher->{_event_queue_h} |
474 | $dispatcher->{_event_queue_h} |
416 | or return; |
475 | or return; |
417 | |
476 | |
418 | # make the dispatcher handle any outstanding stuff |
477 | # make the dispatcher handle any outstanding stuff |
|
|
478 | ... not shown |
419 | |
479 | |
420 | # create an IO watcher for each and every socket |
480 | # create an IO watcher for each and every socket |
421 | @snmp_watcher = ( |
481 | @snmp_watcher = ( |
422 | (map { EV::io $_, EV::READ, sub { } } |
482 | (map { EV::io $_, EV::READ, sub { } } |
423 | keys %{ $dispatcher->{_descriptors} }), |
483 | keys %{ $dispatcher->{_descriptors} }), |
|
|
484 | |
|
|
485 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
|
|
486 | ? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0), |
|
|
487 | 0, sub { }, |
424 | ); |
488 | ); |
425 | |
|
|
426 | # if there are any timeouts, also create a timer |
|
|
427 | push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { } |
|
|
428 | if $event->[Net::SNMP::Dispatcher::_ACTIVE]; |
|
|
429 | }; |
489 | }; |
430 | |
490 | |
431 | The callbacks are irrelevant, the only purpose of those watchers is |
491 | The callbacks are irrelevant (and are not even being called), the |
432 | to wake up the process as soon as one of those events occurs (socket |
492 | only purpose of those watchers is to wake up the process as soon as |
433 | readable, or timer timed out). The corresponding EV::check watcher |
493 | one of those events occurs (socket readable, or timer timed out). |
434 | will then clean up: |
494 | The corresponding EV::check watcher will then clean up: |
435 | |
495 | |
436 | our $snmp_check = EV::check sub { |
496 | our $snmp_check = EV::check sub { |
437 | # destroy all watchers |
497 | # destroy all watchers |
438 | @snmp_watcher = (); |
498 | @snmp_watcher = (); |
439 | |
499 | |
440 | # make the dispatcher handle any new stuff |
500 | # make the dispatcher handle any new stuff |
|
|
501 | ... not shown |
441 | }; |
502 | }; |
442 | |
503 | |
443 | The callbacks of the created watchers will not be called as the |
504 | The callbacks of the created watchers will not be called as the |
444 | watchers are destroyed before this cna happen (remember EV::check |
505 | watchers are destroyed before this cna happen (remember EV::check |
445 | gets called first). |
506 | gets called first). |
446 | |
507 | |
447 | The "check_ns" variant doesn't start (activate) the newly created |
508 | The "check_ns" variant doesn't start (activate) the newly created |
448 | watcher. |
509 | watcher. |
449 | |
510 | |
450 | THREADS |
511 | THREADS |
451 | Threads are not supported by this in any way. Perl pseudo-threads is |
512 | Threads are not supported by this module in any way. Perl pseudo-threads |
452 | evil stuff and must die. |
513 | is evil stuff and must die. As soon as Perl gains real threads I will |
|
|
514 | work on thread support for it. |
|
|
515 | |
|
|
516 | FORK |
|
|
517 | Most of the "improved" event delivering mechanisms of modern operating |
|
|
518 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
|
|
519 | not supported and usually destructive). Libev makes it possible to work |
|
|
520 | around this by having a function that recreates the kernel state after |
|
|
521 | fork in the child. |
|
|
522 | |
|
|
523 | On non-win32 platforms, this module requires the pthread_atfork |
|
|
524 | functionality to do this automatically for you. This function is quite |
|
|
525 | buggy on most BSDs, though, so YMMV. The overhead for this is quite |
|
|
526 | negligible, because everything the function currently does is set a flag |
|
|
527 | that is checked only when the event loop gets used the next time, so |
|
|
528 | when you do fork but not use EV, the overhead is minimal. |
|
|
529 | |
|
|
530 | On win32, there is no notion of fork so all this doesn't apply, of |
|
|
531 | course. |
453 | |
532 | |
454 | SEE ALSO |
533 | SEE ALSO |
455 | L<EV::DNS>. |
534 | L<EV::DNS>. |
456 | |
535 | |
457 | AUTHOR |
536 | AUTHOR |