… | |
… | |
39 | |
39 | |
40 | my $w = EV::child 666, sub { |
40 | my $w = EV::child 666, sub { |
41 | my ($w, $revents) = @_; |
41 | my ($w, $revents) = @_; |
42 | my $status = $w->rstatus; |
42 | my $status = $w->rstatus; |
43 | }; |
43 | }; |
|
|
44 | |
|
|
45 | # STAT CHANGES |
|
|
46 | my $w = EV::stat "/etc/passwd", 10, sub { |
|
|
47 | my ($w, $revents) = @_; |
|
|
48 | warn $w->path, " has changed somehow.\n"; |
|
|
49 | }; |
44 | |
50 | |
45 | # MAINLOOP |
51 | # MAINLOOP |
46 | EV::loop; # loop until EV::unloop is called or all watchers stop |
52 | EV::loop; # loop until EV::unloop is called or all watchers stop |
47 | EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled |
53 | EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled |
48 | EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block |
54 | EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block |
49 | |
55 | |
50 | =head1 DESCRIPTION |
56 | =head1 DESCRIPTION |
51 | |
57 | |
52 | This module provides an interface to libev |
58 | This module provides an interface to libev |
53 | (L<http://software.schmorp.de/pkg/libev.html>). |
59 | (L<http://software.schmorp.de/pkg/libev.html>). While the documentation |
|
|
60 | below is comprehensive, one might also consult the documentation of libev |
|
|
61 | itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on |
|
|
62 | watcher semantics or some discussion on the available backends, or how to |
|
|
63 | force a specific backend with C<LIBEV_FLAGS>, or just about in any case |
|
|
64 | because it has much more detailed information. |
54 | |
65 | |
55 | =cut |
66 | =cut |
56 | |
67 | |
57 | package EV; |
68 | package EV; |
58 | |
69 | |
59 | use strict; |
70 | use strict; |
60 | |
71 | |
61 | BEGIN { |
72 | BEGIN { |
62 | our $VERSION = '0.9'; |
73 | our $VERSION = '1.85'; |
63 | use XSLoader; |
74 | use XSLoader; |
64 | XSLoader::load "EV", $VERSION; |
75 | XSLoader::load "EV", $VERSION; |
65 | } |
76 | } |
66 | |
77 | |
67 | @EV::Io::ISA = |
78 | @EV::IO::ISA = |
68 | @EV::Timer::ISA = |
79 | @EV::Timer::ISA = |
69 | @EV::Periodic::ISA = |
80 | @EV::Periodic::ISA = |
70 | @EV::Signal::ISA = |
81 | @EV::Signal::ISA = |
|
|
82 | @EV::Child::ISA = |
|
|
83 | @EV::Stat::ISA = |
71 | @EV::Idle::ISA = |
84 | @EV::Idle::ISA = |
72 | @EV::Prepare::ISA = |
85 | @EV::Prepare::ISA = |
73 | @EV::Check::ISA = |
86 | @EV::Check::ISA = |
74 | @EV::Child::ISA = "EV::Watcher"; |
87 | @EV::Embed::ISA = |
|
|
88 | @EV::Fork::ISA = |
|
|
89 | "EV::Watcher"; |
75 | |
90 | |
76 | =head1 BASIC INTERFACE |
91 | =head1 BASIC INTERFACE |
77 | |
92 | |
78 | =over 4 |
93 | =over 4 |
79 | |
94 | |
80 | =item $EV::DIED |
95 | =item $EV::DIED |
81 | |
96 | |
82 | Must contain a reference to a function that is called when a callback |
97 | Must contain a reference to a function that is called when a callback |
83 | throws an exception (with $@ containing thr error). The default prints an |
98 | throws an exception (with $@ containing the error). The default prints an |
84 | informative message and continues. |
99 | informative message and continues. |
85 | |
100 | |
86 | If this callback throws an exception it will be silently ignored. |
101 | If this callback throws an exception it will be silently ignored. |
87 | |
102 | |
88 | =item $time = EV::time |
103 | =item $time = EV::time |
… | |
… | |
117 | innermost call to EV::loop return. |
132 | innermost call to EV::loop return. |
118 | |
133 | |
119 | When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as |
134 | When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as |
120 | fast as possible. |
135 | fast as possible. |
121 | |
136 | |
122 | =back |
137 | =item $count = EV::loop_count |
123 | |
138 | |
|
|
139 | Return the number of times the event loop has polled for new |
|
|
140 | events. Sometiems useful as a generation counter. |
|
|
141 | |
|
|
142 | =item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
|
|
143 | |
|
|
144 | This function rolls together an I/O and a timer watcher for a single |
|
|
145 | one-shot event without the need for managing a watcher object. |
|
|
146 | |
|
|
147 | If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> |
|
|
148 | must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ |
|
|
149 | | EV::WRITE>, indicating the type of I/O event you want to wait for. If |
|
|
150 | you do not want to wait for some I/O event, specify C<undef> for |
|
|
151 | C<$fh_or_undef> and C<0> for C<$events>). |
|
|
152 | |
|
|
153 | If timeout is C<undef> or negative, then there will be no |
|
|
154 | timeout. Otherwise a EV::timer with this value will be started. |
|
|
155 | |
|
|
156 | When an error occurs or either the timeout or I/O watcher triggers, then |
|
|
157 | the callback will be called with the received event set (in general |
|
|
158 | you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>, |
|
|
159 | C<EV::WRITE> and C<EV::TIMEOUT>). |
|
|
160 | |
|
|
161 | EV::once doesn't return anything: the watchers stay active till either |
|
|
162 | of them triggers, then they will be stopped and freed, and the callback |
|
|
163 | invoked. |
|
|
164 | |
|
|
165 | =item EV::feed_fd_event ($fd, $revents) |
|
|
166 | |
|
|
167 | Feed an event on a file descriptor into EV. EV will react to this call as |
|
|
168 | if the readyness notifications specified by C<$revents> (a combination of |
|
|
169 | C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. |
|
|
170 | |
|
|
171 | =item EV::feed_signal_event ($signal) |
|
|
172 | |
|
|
173 | Feed a signal event into EV. EV will react to this call as if the signal |
|
|
174 | specified by C<$signal> had occured. |
|
|
175 | |
|
|
176 | =back |
|
|
177 | |
|
|
178 | |
124 | =head2 WATCHER |
179 | =head2 WATCHER OBJECTS |
125 | |
180 | |
126 | A watcher is an object that gets created to record your interest in some |
181 | A watcher is an object that gets created to record your interest in some |
127 | event. For instance, if you want to wait for STDIN to become readable, you |
182 | event. For instance, if you want to wait for STDIN to become readable, you |
128 | would create an EV::io watcher for that: |
183 | would create an EV::io watcher for that: |
129 | |
184 | |
… | |
… | |
138 | events. |
193 | events. |
139 | |
194 | |
140 | Each watcher type has its associated bit in revents, so you can use the |
195 | Each watcher type has its associated bit in revents, so you can use the |
141 | same callback for multiple watchers. The event mask is named after the |
196 | same callback for multiple watchers. The event mask is named after the |
142 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
197 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
143 | EV::periodic sets EV::PERIODIC and so on, with the exception of IO events |
198 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events |
144 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
199 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
145 | uses EV::TIMEOUT). |
200 | uses EV::TIMEOUT). |
146 | |
201 | |
147 | In the rare case where one wants to create a watcher but not start it at |
202 | In the rare case where one wants to create a watcher but not start it at |
148 | the same time, each constructor has a variant with a trailing C<_ns> in |
203 | the same time, each constructor has a variant with a trailing C<_ns> in |
… | |
… | |
154 | |
209 | |
155 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
210 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
156 | ->fh and so on) automatically stop and start it again if it is active, |
211 | ->fh and so on) automatically stop and start it again if it is active, |
157 | which means pending events get lost. |
212 | which means pending events get lost. |
158 | |
213 | |
159 | =head2 WATCHER TYPES |
214 | =head2 COMMON WATCHER METHODS |
160 | |
215 | |
161 | Now lets move to the existing watcher types and asociated methods. |
216 | This section lists methods common to all watchers. |
162 | |
|
|
163 | The following methods are available for all watchers. Then followes a |
|
|
164 | description of each watcher constructor (EV::io, EV::timer, EV::periodic, |
|
|
165 | EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by |
|
|
166 | any type-specific methods (if any). |
|
|
167 | |
217 | |
168 | =over 4 |
218 | =over 4 |
169 | |
219 | |
170 | =item $w->start |
220 | =item $w->start |
171 | |
221 | |
… | |
… | |
175 | |
225 | |
176 | =item $w->stop |
226 | =item $w->stop |
177 | |
227 | |
178 | Stop a watcher if it is active. Also clear any pending events (events that |
228 | Stop a watcher if it is active. Also clear any pending events (events that |
179 | have been received but that didn't yet result in a callback invocation), |
229 | have been received but that didn't yet result in a callback invocation), |
180 | regardless of wether the watcher was active or not. |
230 | regardless of whether the watcher was active or not. |
181 | |
231 | |
182 | =item $bool = $w->is_active |
232 | =item $bool = $w->is_active |
183 | |
233 | |
184 | Returns true if the watcher is active, false otherwise. |
234 | Returns true if the watcher is active, false otherwise. |
185 | |
235 | |
… | |
… | |
210 | watchers with higher priority will be invoked first. The valid range of |
260 | watchers with higher priority will be invoked first. The valid range of |
211 | priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default |
261 | priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default |
212 | -2). If the priority is outside this range it will automatically be |
262 | -2). If the priority is outside this range it will automatically be |
213 | normalised to the nearest valid priority. |
263 | normalised to the nearest valid priority. |
214 | |
264 | |
215 | The default priority of any newly-created weatcher is 0. |
265 | The default priority of any newly-created watcher is 0. |
216 | |
266 | |
|
|
267 | Note that the priority semantics have not yet been fleshed out and are |
|
|
268 | subject to almost certain change. |
|
|
269 | |
217 | =item $w->trigger ($revents) |
270 | =item $w->invoke ($revents) |
218 | |
271 | |
219 | Call the callback *now* with the given event mask. |
272 | Call the callback *now* with the given event mask. |
220 | |
273 | |
|
|
274 | =item $w->feed_event ($revents) |
|
|
275 | |
|
|
276 | Feed some events on this watcher into EV. EV will react to this call as if |
|
|
277 | the watcher had received the given C<$revents> mask. |
|
|
278 | |
|
|
279 | =item $revents = $w->clear_pending |
|
|
280 | |
|
|
281 | If the watcher is pending, this function returns clears its pending status |
|
|
282 | and returns its C<$revents> bitset (as if its callback was invoked). If the |
|
|
283 | watcher isn't pending it does nothing and returns C<0>. |
|
|
284 | |
|
|
285 | =item $previous_state = $w->keepalive ($bool) |
|
|
286 | |
|
|
287 | Normally, C<EV::loop> will return when there are no active watchers |
|
|
288 | (which is a "deadlock" because no progress can be made anymore). This is |
|
|
289 | convinient because it allows you to start your watchers (and your jobs), |
|
|
290 | call C<EV::loop> once and when it returns you know that all your jobs are |
|
|
291 | finished (or they forgot to register some watchers for their task :). |
|
|
292 | |
|
|
293 | Sometimes, however, this gets in your way, for example when you the module |
|
|
294 | that calls C<EV::loop> (usually the main program) is not the same module |
|
|
295 | as a long-living watcher (for example a DNS client module written by |
|
|
296 | somebody else even). Then you might want any outstanding requests to be |
|
|
297 | handled, but you would not want to keep C<EV::loop> from returning just |
|
|
298 | because you happen to have this long-running UDP port watcher. |
|
|
299 | |
|
|
300 | In this case you can clear the keepalive status, which means that even |
|
|
301 | though your watcher is active, it won't keep C<EV::loop> from returning. |
|
|
302 | |
|
|
303 | The initial value for keepalive is true (enabled), and you cna change it |
|
|
304 | any time. |
|
|
305 | |
|
|
306 | Example: Register an I/O watcher for some UDP socket but do not keep the |
|
|
307 | event loop from running just because of that watcher. |
|
|
308 | |
|
|
309 | my $udp_socket = ... |
|
|
310 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
|
|
311 | $udp_watcher->keepalive (0); |
|
|
312 | |
|
|
313 | =back |
|
|
314 | |
|
|
315 | |
|
|
316 | =head2 WATCHER TYPES |
|
|
317 | |
|
|
318 | Each of the following subsections describes a single watcher type. |
|
|
319 | |
|
|
320 | =head3 I/O WATCHERS - is this file descriptor readable or writable? |
|
|
321 | |
|
|
322 | =over 4 |
221 | |
323 | |
222 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
324 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
223 | |
325 | |
224 | =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
326 | =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
225 | |
327 | |
226 | As long as the returned watcher object is alive, call the C<$callback> |
328 | As long as the returned watcher object is alive, call the C<$callback> |
227 | when the events specified in C<$eventmask>. |
329 | when at least one of events specified in C<$eventmask> occurs. |
228 | |
330 | |
229 | The $eventmask can be one or more of these constants ORed together: |
331 | The $eventmask can be one or more of these constants ORed together: |
230 | |
332 | |
231 | EV::READ wait until read() wouldn't block anymore |
333 | EV::READ wait until read() wouldn't block anymore |
232 | EV::WRITE wait until write() wouldn't block anymore |
334 | EV::WRITE wait until write() wouldn't block anymore |
… | |
… | |
248 | |
350 | |
249 | =item $old_eventmask = $w->events ($new_eventmask) |
351 | =item $old_eventmask = $w->events ($new_eventmask) |
250 | |
352 | |
251 | Returns the previously set event mask and optionally set a new one. |
353 | Returns the previously set event mask and optionally set a new one. |
252 | |
354 | |
|
|
355 | =back |
|
|
356 | |
|
|
357 | |
|
|
358 | =head3 TIMER WATCHERS - relative and optionally repeating timeouts |
|
|
359 | |
|
|
360 | =over 4 |
253 | |
361 | |
254 | =item $w = EV::timer $after, $repeat, $callback |
362 | =item $w = EV::timer $after, $repeat, $callback |
255 | |
363 | |
256 | =item $w = EV::timer_ns $after, $repeat, $callback |
364 | =item $w = EV::timer_ns $after, $repeat, $callback |
257 | |
365 | |
258 | Calls the callback after C<$after> seconds. If C<$repeat> is non-zero, |
366 | Calls the callback after C<$after> seconds (which may be fractional). If |
259 | the timer will be restarted (with the $repeat value as $after) after the |
367 | C<$repeat> is non-zero, the timer will be restarted (with the $repeat |
260 | callback returns. |
368 | value as $after) after the callback returns. |
261 | |
369 | |
262 | This means that the callback would be called roughly after C<$after> |
370 | This means that the callback would be called roughly after C<$after> |
263 | seconds, and then every C<$repeat> seconds. The timer does his best not |
371 | seconds, and then every C<$repeat> seconds. The timer does his best not |
264 | to drift, but it will not invoke the timer more often then once per event |
372 | to drift, but it will not invoke the timer more often then once per event |
265 | loop iteration, and might drift in other cases. If that isn't acceptable, |
373 | loop iteration, and might drift in other cases. If that isn't acceptable, |
… | |
… | |
271 | |
379 | |
272 | The C<timer_ns> variant doesn't start (activate) the newly created watcher. |
380 | The C<timer_ns> variant doesn't start (activate) the newly created watcher. |
273 | |
381 | |
274 | =item $w->set ($after, $repeat) |
382 | =item $w->set ($after, $repeat) |
275 | |
383 | |
276 | Reconfigures the watcher, see the constructor above for details. Can be at |
384 | Reconfigures the watcher, see the constructor above for details. Can be called at |
277 | any time. |
385 | any time. |
278 | |
386 | |
279 | =item $w->again |
387 | =item $w->again |
280 | |
388 | |
281 | Similar to the C<start> method, but has special semantics for repeating timers: |
389 | Similar to the C<start> method, but has special semantics for repeating timers: |
… | |
… | |
292 | This behaviour is useful when you have a timeout for some IO |
400 | This behaviour is useful when you have a timeout for some IO |
293 | operation. You create a timer object with the same value for C<$after> and |
401 | operation. You create a timer object with the same value for C<$after> and |
294 | C<$repeat>, and then, in the read/write watcher, run the C<again> method |
402 | C<$repeat>, and then, in the read/write watcher, run the C<again> method |
295 | on the timeout. |
403 | on the timeout. |
296 | |
404 | |
|
|
405 | =back |
|
|
406 | |
|
|
407 | |
|
|
408 | =head3 PERIODIC WATCHERS - to cron or not to cron? |
|
|
409 | |
|
|
410 | =over 4 |
297 | |
411 | |
298 | =item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
412 | =item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
299 | |
413 | |
300 | =item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
414 | =item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
301 | |
415 | |
… | |
… | |
373 | |
487 | |
374 | The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
488 | The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
375 | |
489 | |
376 | =item $w->set ($at, $interval, $reschedule_cb) |
490 | =item $w->set ($at, $interval, $reschedule_cb) |
377 | |
491 | |
378 | Reconfigures the watcher, see the constructor above for details. Can be at |
492 | Reconfigures the watcher, see the constructor above for details. Can be called at |
379 | any time. |
493 | any time. |
380 | |
494 | |
381 | =item $w->again |
495 | =item $w->again |
382 | |
496 | |
383 | Simply stops and starts the watcher again. |
497 | Simply stops and starts the watcher again. |
384 | |
498 | |
|
|
499 | =back |
|
|
500 | |
|
|
501 | |
|
|
502 | =head3 SIGNAL WATCHERS - signal me when a signal gets signalled! |
|
|
503 | |
|
|
504 | =over 4 |
385 | |
505 | |
386 | =item $w = EV::signal $signal, $callback |
506 | =item $w = EV::signal $signal, $callback |
387 | |
507 | |
388 | =item $w = EV::signal_ns $signal, $callback |
508 | =item $w = EV::signal_ns $signal, $callback |
389 | |
509 | |
390 | Call the callback when $signal is received (the signal can be specified |
510 | Call the callback when $signal is received (the signal can be specified by |
391 | by number or by name, just as with kill or %SIG). |
511 | number or by name, just as with C<kill> or C<%SIG>). |
392 | |
512 | |
393 | EV will grab the signal for the process (the kernel only allows one |
513 | EV will grab the signal for the process (the kernel only allows one |
394 | component to receive a signal at a time) when you start a signal watcher, |
514 | component to receive a signal at a time) when you start a signal watcher, |
395 | and removes it again when you stop it. Perl does the same when you |
515 | and removes it again when you stop it. Perl does the same when you |
396 | add/remove callbacks to %SIG, so watch out. |
516 | add/remove callbacks to C<%SIG>, so watch out. |
397 | |
517 | |
398 | You can have as many signal watchers per signal as you want. |
518 | You can have as many signal watchers per signal as you want. |
399 | |
519 | |
400 | The C<signal_ns> variant doesn't start (activate) the newly created watcher. |
520 | The C<signal_ns> variant doesn't start (activate) the newly created watcher. |
401 | |
521 | |
402 | =item $w->set ($signal) |
522 | =item $w->set ($signal) |
403 | |
523 | |
404 | Reconfigures the watcher, see the constructor above for details. Can be at |
524 | Reconfigures the watcher, see the constructor above for details. Can be |
405 | any time. |
525 | called at any time. |
406 | |
526 | |
407 | =item $current_signum = $w->signal |
527 | =item $current_signum = $w->signal |
408 | |
528 | |
409 | =item $old_signum = $w->signal ($new_signal) |
529 | =item $old_signum = $w->signal ($new_signal) |
410 | |
530 | |
411 | Returns the previously set signal (always as a number not name) and |
531 | Returns the previously set signal (always as a number not name) and |
412 | optionally set a new one. |
532 | optionally set a new one. |
413 | |
533 | |
|
|
534 | =back |
|
|
535 | |
|
|
536 | |
|
|
537 | =head3 CHILD WATCHERS - watch out for process status changes |
|
|
538 | |
|
|
539 | =over 4 |
414 | |
540 | |
415 | =item $w = EV::child $pid, $callback |
541 | =item $w = EV::child $pid, $callback |
416 | |
542 | |
417 | =item $w = EV::child_ns $pid, $callback |
543 | =item $w = EV::child_ns $pid, $callback |
418 | |
544 | |
419 | Call the callback when a status change for pid C<$pid> (or any pid |
545 | Call the callback when a status change for pid C<$pid> (or any pid if |
420 | if C<$pid> is 0) has been received. More precisely: when the process |
546 | C<$pid> is 0) has been received. More precisely: when the process receives |
421 | receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all |
547 | a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all |
422 | changed/zombie children and call the callback. |
548 | changed/zombie children and call the callback. |
423 | |
549 | |
424 | You can access both status and pid by using the C<rstatus> and C<rpid> |
550 | It is valid (and fully supported) to install a child watcher after a child |
425 | methods on the watcher object. |
551 | has exited but before the event loop has started its next iteration (for |
|
|
552 | example, first you C<fork>, then the new child process might exit, and |
|
|
553 | only then do you install a child watcher in the parent for the new pid). |
426 | |
554 | |
|
|
555 | You can access both exit (or tracing) status and pid by using the |
|
|
556 | C<rstatus> and C<rpid> methods on the watcher object. |
|
|
557 | |
427 | You can have as many pid watchers per pid as you want. |
558 | You can have as many pid watchers per pid as you want, they will all be |
|
|
559 | called. |
428 | |
560 | |
429 | The C<child_ns> variant doesn't start (activate) the newly created watcher. |
561 | The C<child_ns> variant doesn't start (activate) the newly created watcher. |
430 | |
562 | |
431 | =item $w->set ($pid) |
563 | =item $w->set ($pid) |
432 | |
564 | |
433 | Reconfigures the watcher, see the constructor above for details. Can be at |
565 | Reconfigures the watcher, see the constructor above for details. Can be called at |
434 | any time. |
566 | any time. |
435 | |
567 | |
436 | =item $current_pid = $w->pid |
568 | =item $current_pid = $w->pid |
437 | |
569 | |
438 | =item $old_pid = $w->pid ($new_pid) |
570 | =item $old_pid = $w->pid ($new_pid) |
… | |
… | |
447 | =item $pid = $w->rpid |
579 | =item $pid = $w->rpid |
448 | |
580 | |
449 | Return the pid of the awaited child (useful when you have installed a |
581 | Return the pid of the awaited child (useful when you have installed a |
450 | watcher for all pids). |
582 | watcher for all pids). |
451 | |
583 | |
|
|
584 | =back |
|
|
585 | |
|
|
586 | |
|
|
587 | =head3 STAT WATCHERS - did the file attributes just change? |
|
|
588 | |
|
|
589 | =over 4 |
|
|
590 | |
|
|
591 | =item $w = EV::stat $path, $interval, $callback |
|
|
592 | |
|
|
593 | =item $w = EV::stat_ns $path, $interval, $callback |
|
|
594 | |
|
|
595 | Call the callback when a file status change has been detected on |
|
|
596 | C<$path>. The C<$path> does not need to exist, changing from "path exists" |
|
|
597 | to "path does not exist" is a status change like any other. |
|
|
598 | |
|
|
599 | The C<$interval> is a recommended polling interval for systems where |
|
|
600 | OS-supported change notifications don't exist or are not supported. If |
|
|
601 | you use C<0> then an unspecified default is used (which is highly |
|
|
602 | recommended!), which is to be expected to be around five seconds usually. |
|
|
603 | |
|
|
604 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
605 | as even with OS-supported change notifications, this can be |
|
|
606 | resource-intensive. |
|
|
607 | |
|
|
608 | The C<stat_ns> variant doesn't start (activate) the newly created watcher. |
|
|
609 | |
|
|
610 | =item ... = $w->stat |
|
|
611 | |
|
|
612 | This call is very similar to the perl C<stat> built-in: It stats (using |
|
|
613 | C<lstat>) the path specified in the watcher and sets perls stat cache (as |
|
|
614 | well as EV's idea of the current stat values) to the values found. |
|
|
615 | |
|
|
616 | In scalar context, a boolean is return indicating success or failure of |
|
|
617 | the stat. In list context, the same 13-value list as with stat is returned |
|
|
618 | (except that the blksize and blocks fields are not reliable). |
|
|
619 | |
|
|
620 | In the case of an error, errno is set to C<ENOENT> (regardless of the |
|
|
621 | actual error value) and the C<nlink> value is forced to zero (if the stat |
|
|
622 | was successful then nlink is guaranteed to be non-zero). |
|
|
623 | |
|
|
624 | See also the next two entries for more info. |
|
|
625 | |
|
|
626 | =item ... = $w->attr |
|
|
627 | |
|
|
628 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
|
|
629 | the values most recently detected by EV. See the next entry for more info. |
|
|
630 | |
|
|
631 | =item ... = $w->prev |
|
|
632 | |
|
|
633 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
|
|
634 | the previous set of values, before the change. |
|
|
635 | |
|
|
636 | That is, when the watcher callback is invoked, C<< $w->prev >> will be set |
|
|
637 | to the values found I<before> a change was detected, while C<< $w->attr >> |
|
|
638 | returns the values found leading to the change detection. The difference (if any) |
|
|
639 | between C<prev> and C<attr> is what triggered the callback. |
|
|
640 | |
|
|
641 | If you did something to the filesystem object and do not want to trigger |
|
|
642 | yet another change, you can call C<stat> to update EV's idea of what the |
|
|
643 | current attributes are. |
|
|
644 | |
|
|
645 | =item $w->set ($path, $interval) |
|
|
646 | |
|
|
647 | Reconfigures the watcher, see the constructor above for details. Can be |
|
|
648 | called at any time. |
|
|
649 | |
|
|
650 | =item $current_path = $w->path |
|
|
651 | |
|
|
652 | =item $old_path = $w->path ($new_path) |
|
|
653 | |
|
|
654 | Returns the previously set path and optionally set a new one. |
|
|
655 | |
|
|
656 | =item $current_interval = $w->interval |
|
|
657 | |
|
|
658 | =item $old_interval = $w->interval ($new_interval) |
|
|
659 | |
|
|
660 | Returns the previously set interval and optionally set a new one. Can be |
|
|
661 | used to query the actual interval used. |
|
|
662 | |
|
|
663 | =back |
|
|
664 | |
|
|
665 | |
|
|
666 | =head3 IDLE WATCHERS - when you've got nothing better to do... |
|
|
667 | |
|
|
668 | =over 4 |
452 | |
669 | |
453 | =item $w = EV::idle $callback |
670 | =item $w = EV::idle $callback |
454 | |
671 | |
455 | =item $w = EV::idle_ns $callback |
672 | =item $w = EV::idle_ns $callback |
456 | |
673 | |
457 | Call the callback when there are no pending io, timer/periodic, signal or |
674 | Call the callback when there are no other pending watchers of the same or |
458 | child events, i.e. when the process is idle. |
675 | higher priority (excluding check, prepare and other idle watchers of the |
|
|
676 | same or lower priority, of course). They are called idle watchers because |
|
|
677 | when the watcher is the highest priority pending event in the process, the |
|
|
678 | process is considered to be idle at that priority. |
|
|
679 | |
|
|
680 | If you want a watcher that is only ever called when I<no> other events are |
|
|
681 | outstanding you have to set the priority to C<EV::MINPRI>. |
459 | |
682 | |
460 | The process will not block as long as any idle watchers are active, and |
683 | The process will not block as long as any idle watchers are active, and |
461 | they will be called repeatedly until stopped. |
684 | they will be called repeatedly until stopped. |
462 | |
685 | |
|
|
686 | For example, if you have idle watchers at priority C<0> and C<1>, and |
|
|
687 | an I/O watcher at priority C<0>, then the idle watcher at priority C<1> |
|
|
688 | and the I/O watcher will always run when ready. Only when the idle watcher |
|
|
689 | at priority C<1> is stopped and the I/O watcher at priority C<0> is not |
|
|
690 | pending with the C<0>-priority idle watcher be invoked. |
|
|
691 | |
463 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
692 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
464 | |
693 | |
|
|
694 | =back |
|
|
695 | |
|
|
696 | |
|
|
697 | =head3 PREPARE WATCHERS - customise your event loop! |
|
|
698 | |
|
|
699 | =over 4 |
465 | |
700 | |
466 | =item $w = EV::prepare $callback |
701 | =item $w = EV::prepare $callback |
467 | |
702 | |
468 | =item $w = EV::prepare_ns $callback |
703 | =item $w = EV::prepare_ns $callback |
469 | |
704 | |
… | |
… | |
472 | |
707 | |
473 | See the EV::check watcher, below, for explanations and an example. |
708 | See the EV::check watcher, below, for explanations and an example. |
474 | |
709 | |
475 | The C<prepare_ns> variant doesn't start (activate) the newly created watcher. |
710 | The C<prepare_ns> variant doesn't start (activate) the newly created watcher. |
476 | |
711 | |
|
|
712 | =back |
|
|
713 | |
|
|
714 | |
|
|
715 | =head3 CHECK WATCHERS - customise your event loop even more! |
|
|
716 | |
|
|
717 | =over 4 |
477 | |
718 | |
478 | =item $w = EV::check $callback |
719 | =item $w = EV::check $callback |
479 | |
720 | |
480 | =item $w = EV::check_ns $callback |
721 | =item $w = EV::check_ns $callback |
481 | |
722 | |
… | |
… | |
493 | # do nothing unless active |
734 | # do nothing unless active |
494 | $dispatcher->{_event_queue_h} |
735 | $dispatcher->{_event_queue_h} |
495 | or return; |
736 | or return; |
496 | |
737 | |
497 | # make the dispatcher handle any outstanding stuff |
738 | # make the dispatcher handle any outstanding stuff |
|
|
739 | ... not shown |
498 | |
740 | |
499 | # create an IO watcher for each and every socket |
741 | # create an I/O watcher for each and every socket |
500 | @snmp_watcher = ( |
742 | @snmp_watcher = ( |
501 | (map { EV::io $_, EV::READ, sub { } } |
743 | (map { EV::io $_, EV::READ, sub { } } |
502 | keys %{ $dispatcher->{_descriptors} }), |
744 | keys %{ $dispatcher->{_descriptors} }), |
|
|
745 | |
|
|
746 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
|
|
747 | ? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0), |
|
|
748 | 0, sub { }, |
503 | ); |
749 | ); |
504 | |
|
|
505 | # if there are any timeouts, also create a timer |
|
|
506 | push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { } |
|
|
507 | if $event->[Net::SNMP::Dispatcher::_ACTIVE]; |
|
|
508 | }; |
750 | }; |
509 | |
751 | |
510 | The callbacks are irrelevant, the only purpose of those watchers is |
752 | The callbacks are irrelevant (and are not even being called), the |
511 | to wake up the process as soon as one of those events occurs (socket |
753 | only purpose of those watchers is to wake up the process as soon as |
512 | readable, or timer timed out). The corresponding EV::check watcher will then |
754 | one of those events occurs (socket readable, or timer timed out). The |
513 | clean up: |
755 | corresponding EV::check watcher will then clean up: |
514 | |
756 | |
515 | our $snmp_check = EV::check sub { |
757 | our $snmp_check = EV::check sub { |
516 | # destroy all watchers |
758 | # destroy all watchers |
517 | @snmp_watcher = (); |
759 | @snmp_watcher = (); |
518 | |
760 | |
519 | # make the dispatcher handle any new stuff |
761 | # make the dispatcher handle any new stuff |
|
|
762 | ... not shown |
520 | }; |
763 | }; |
521 | |
764 | |
522 | The callbacks of the created watchers will not be called as the watchers |
765 | The callbacks of the created watchers will not be called as the watchers |
523 | are destroyed before this cna happen (remember EV::check gets called |
766 | are destroyed before this cna happen (remember EV::check gets called |
524 | first). |
767 | first). |
525 | |
768 | |
526 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
769 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
527 | |
770 | |
528 | =back |
771 | =back |
529 | |
772 | |
|
|
773 | |
|
|
774 | =head3 FORK WATCHERS - the audacity to resume the event loop after a fork |
|
|
775 | |
|
|
776 | Fork watchers are called when a C<fork ()> was detected. The invocation |
|
|
777 | is done before the event loop blocks next and before C<check> watchers |
|
|
778 | are being called, and only in the child after the fork. |
|
|
779 | |
|
|
780 | =over 4 |
|
|
781 | |
|
|
782 | =item $w = EV::fork $callback |
|
|
783 | |
|
|
784 | =item $w = EV::fork_ns $callback |
|
|
785 | |
|
|
786 | Call the callback before the event loop is resumed in the child process |
|
|
787 | after a fork. |
|
|
788 | |
|
|
789 | The C<fork_ns> variant doesn't start (activate) the newly created watcher. |
|
|
790 | |
|
|
791 | =back |
|
|
792 | |
|
|
793 | |
|
|
794 | =head1 PERL SIGNALS |
|
|
795 | |
|
|
796 | While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour |
|
|
797 | with EV is as the same as any other C library: Perl-signals will only be |
|
|
798 | handled when Perl runs, which means your signal handler might be invoked |
|
|
799 | only the next time an event callback is invoked. |
|
|
800 | |
|
|
801 | The solution is to use EV signal watchers (see C<EV::signal>), which will |
|
|
802 | ensure proper operations with regards to other event watchers. |
|
|
803 | |
|
|
804 | If you cannot do this for whatever reason, you can also force a watcher |
|
|
805 | to be called on every event loop iteration by installing a C<EV::check> |
|
|
806 | watcher: |
|
|
807 | |
|
|
808 | my $async_check = EV::check sub { }; |
|
|
809 | |
|
|
810 | This ensures that perl shortly gets into control for a short time, and |
|
|
811 | also ensures slower overall operation. |
|
|
812 | |
530 | =head1 THREADS |
813 | =head1 THREADS |
531 | |
814 | |
532 | Threads are not supported by this in any way. Perl pseudo-threads is evil |
815 | Threads are not supported by this module in any way. Perl pseudo-threads |
533 | stuff and must die. |
816 | is evil stuff and must die. As soon as Perl gains real threads I will work |
|
|
817 | on thread support for it. |
|
|
818 | |
|
|
819 | =head1 FORK |
|
|
820 | |
|
|
821 | Most of the "improved" event delivering mechanisms of modern operating |
|
|
822 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
|
|
823 | not supported and usually destructive). Libev makes it possible to work |
|
|
824 | around this by having a function that recreates the kernel state after |
|
|
825 | fork in the child. |
|
|
826 | |
|
|
827 | On non-win32 platforms, this module requires the pthread_atfork |
|
|
828 | functionality to do this automatically for you. This function is quite |
|
|
829 | buggy on most BSDs, though, so YMMV. The overhead for this is quite |
|
|
830 | negligible, because everything the function currently does is set a flag |
|
|
831 | that is checked only when the event loop gets used the next time, so when |
|
|
832 | you do fork but not use EV, the overhead is minimal. |
|
|
833 | |
|
|
834 | On win32, there is no notion of fork so all this doesn't apply, of course. |
534 | |
835 | |
535 | =cut |
836 | =cut |
536 | |
837 | |
537 | our $DIED = sub { |
838 | our $DIED = sub { |
538 | warn "EV: error in callback (ignoring): $@"; |
839 | warn "EV: error in callback (ignoring): $@"; |
539 | }; |
840 | }; |
540 | |
841 | |
541 | default_loop |
842 | default_loop |
542 | or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; |
843 | or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?'; |
543 | |
844 | |
544 | 1; |
845 | 1; |
545 | |
846 | |
546 | =head1 SEE ALSO |
847 | =head1 SEE ALSO |
547 | |
848 | |
548 | L<EV::DNS>. |
849 | L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as |
|
|
850 | event loop), L<Coro::EV> (efficient coroutines with EV). |
549 | |
851 | |
550 | =head1 AUTHOR |
852 | =head1 AUTHOR |
551 | |
853 | |
552 | Marc Lehmann <schmorp@schmorp.de> |
854 | Marc Lehmann <schmorp@schmorp.de> |
553 | http://home.schmorp.de/ |
855 | http://home.schmorp.de/ |