… | |
… | |
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 |
|
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46 | my $w = EV::stat "/etc/passwd", 10, sub { |
|
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47 | my ($w, $revents) = @_; |
|
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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 |
|
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60 | below is comprehensive, one might also consult the documentation of libev |
|
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61 | itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on |
|
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62 | watcher semantics or some discussion on the available backends, or how to |
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63 | force a specific backend with C<LIBEV_FLAGS>, or just about in any case |
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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 = '1.2'; |
73 | our $VERSION = '2.0'; |
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 = |
|
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88 | @EV::Fork::ISA = |
|
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89 | "EV::Watcher"; |
|
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90 | |
|
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91 | @EV::Loop::Default::ISA = "EV::Loop"; |
75 | |
92 | |
76 | =head1 BASIC INTERFACE |
93 | =head1 BASIC INTERFACE |
77 | |
94 | |
78 | =over 4 |
95 | =over 4 |
79 | |
96 | |
80 | =item $EV::DIED |
97 | =item $EV::DIED |
81 | |
98 | |
82 | Must contain a reference to a function that is called when a callback |
99 | 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 |
100 | throws an exception (with $@ containing the error). The default prints an |
84 | informative message and continues. |
101 | informative message and continues. |
85 | |
102 | |
86 | If this callback throws an exception it will be silently ignored. |
103 | If this callback throws an exception it will be silently ignored. |
87 | |
104 | |
88 | =item $time = EV::time |
105 | =item $time = EV::time |
… | |
… | |
116 | When called with no arguments or an argument of EV::UNLOOP_ONE, makes the |
133 | When called with no arguments or an argument of EV::UNLOOP_ONE, makes the |
117 | innermost call to EV::loop return. |
134 | innermost call to EV::loop return. |
118 | |
135 | |
119 | When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as |
136 | When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as |
120 | fast as possible. |
137 | fast as possible. |
|
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138 | |
|
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139 | =item $count = EV::loop_count |
|
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140 | |
|
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141 | Return the number of times the event loop has polled for new |
|
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142 | events. Sometiems useful as a generation counter. |
121 | |
143 | |
122 | =item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
144 | =item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
123 | |
145 | |
124 | This function rolls together an I/O and a timer watcher for a single |
146 | This function rolls together an I/O and a timer watcher for a single |
125 | one-shot event without the need for managing a watcher object. |
147 | one-shot event without the need for managing a watcher object. |
… | |
… | |
140 | |
162 | |
141 | EV::once doesn't return anything: the watchers stay active till either |
163 | EV::once doesn't return anything: the watchers stay active till either |
142 | of them triggers, then they will be stopped and freed, and the callback |
164 | of them triggers, then they will be stopped and freed, and the callback |
143 | invoked. |
165 | invoked. |
144 | |
166 | |
145 | =back |
167 | =item EV::feed_fd_event ($fd, $revents) |
146 | |
168 | |
|
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169 | Feed an event on a file descriptor into EV. EV will react to this call as |
|
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170 | if the readyness notifications specified by C<$revents> (a combination of |
|
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171 | C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. |
|
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172 | |
|
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173 | =item EV::feed_signal_event ($signal) |
|
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174 | |
|
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175 | Feed a signal event into EV. EV will react to this call as if the signal |
|
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176 | specified by C<$signal> had occured. |
|
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177 | |
|
|
178 | =back |
|
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179 | |
|
|
180 | |
147 | =head2 WATCHER |
181 | =head2 WATCHER OBJECTS |
148 | |
182 | |
149 | A watcher is an object that gets created to record your interest in some |
183 | A watcher is an object that gets created to record your interest in some |
150 | event. For instance, if you want to wait for STDIN to become readable, you |
184 | event. For instance, if you want to wait for STDIN to become readable, you |
151 | would create an EV::io watcher for that: |
185 | would create an EV::io watcher for that: |
152 | |
186 | |
… | |
… | |
161 | events. |
195 | events. |
162 | |
196 | |
163 | Each watcher type has its associated bit in revents, so you can use the |
197 | Each watcher type has its associated bit in revents, so you can use the |
164 | same callback for multiple watchers. The event mask is named after the |
198 | same callback for multiple watchers. The event mask is named after the |
165 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
199 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
166 | EV::periodic sets EV::PERIODIC and so on, with the exception of IO events |
200 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events |
167 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
201 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
168 | uses EV::TIMEOUT). |
202 | uses EV::TIMEOUT). |
169 | |
203 | |
170 | In the rare case where one wants to create a watcher but not start it at |
204 | In the rare case where one wants to create a watcher but not start it at |
171 | the same time, each constructor has a variant with a trailing C<_ns> in |
205 | the same time, each constructor has a variant with a trailing C<_ns> in |
… | |
… | |
177 | |
211 | |
178 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
212 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
179 | ->fh and so on) automatically stop and start it again if it is active, |
213 | ->fh and so on) automatically stop and start it again if it is active, |
180 | which means pending events get lost. |
214 | which means pending events get lost. |
181 | |
215 | |
182 | =head2 WATCHER TYPES |
216 | =head2 COMMON WATCHER METHODS |
183 | |
217 | |
184 | Now lets move to the existing watcher types and asociated methods. |
218 | This section lists methods common to all watchers. |
185 | |
|
|
186 | The following methods are available for all watchers. Then followes a |
|
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187 | description of each watcher constructor (EV::io, EV::timer, EV::periodic, |
|
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188 | EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by |
|
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189 | any type-specific methods (if any). |
|
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190 | |
219 | |
191 | =over 4 |
220 | =over 4 |
192 | |
221 | |
193 | =item $w->start |
222 | =item $w->start |
194 | |
223 | |
… | |
… | |
198 | |
227 | |
199 | =item $w->stop |
228 | =item $w->stop |
200 | |
229 | |
201 | Stop a watcher if it is active. Also clear any pending events (events that |
230 | Stop a watcher if it is active. Also clear any pending events (events that |
202 | have been received but that didn't yet result in a callback invocation), |
231 | have been received but that didn't yet result in a callback invocation), |
203 | regardless of wether the watcher was active or not. |
232 | regardless of whether the watcher was active or not. |
204 | |
233 | |
205 | =item $bool = $w->is_active |
234 | =item $bool = $w->is_active |
206 | |
235 | |
207 | Returns true if the watcher is active, false otherwise. |
236 | Returns true if the watcher is active, false otherwise. |
208 | |
237 | |
… | |
… | |
233 | watchers with higher priority will be invoked first. The valid range of |
262 | watchers with higher priority will be invoked first. The valid range of |
234 | priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default |
263 | priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default |
235 | -2). If the priority is outside this range it will automatically be |
264 | -2). If the priority is outside this range it will automatically be |
236 | normalised to the nearest valid priority. |
265 | normalised to the nearest valid priority. |
237 | |
266 | |
238 | The default priority of any newly-created weatcher is 0. |
267 | The default priority of any newly-created watcher is 0. |
239 | |
268 | |
|
|
269 | Note that the priority semantics have not yet been fleshed out and are |
|
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270 | subject to almost certain change. |
|
|
271 | |
240 | =item $w->trigger ($revents) |
272 | =item $w->invoke ($revents) |
241 | |
273 | |
242 | Call the callback *now* with the given event mask. |
274 | Call the callback *now* with the given event mask. |
243 | |
275 | |
|
|
276 | =item $w->feed_event ($revents) |
|
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277 | |
|
|
278 | Feed some events on this watcher into EV. EV will react to this call as if |
|
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279 | the watcher had received the given C<$revents> mask. |
|
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280 | |
|
|
281 | =item $revents = $w->clear_pending |
|
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282 | |
|
|
283 | If the watcher is pending, this function returns clears its pending status |
|
|
284 | and returns its C<$revents> bitset (as if its callback was invoked). If the |
|
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285 | watcher isn't pending it does nothing and returns C<0>. |
|
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286 | |
|
|
287 | =item $previous_state = $w->keepalive ($bool) |
|
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288 | |
|
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289 | Normally, C<EV::loop> will return when there are no active watchers |
|
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290 | (which is a "deadlock" because no progress can be made anymore). This is |
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291 | convinient because it allows you to start your watchers (and your jobs), |
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292 | call C<EV::loop> once and when it returns you know that all your jobs are |
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293 | finished (or they forgot to register some watchers for their task :). |
|
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294 | |
|
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295 | Sometimes, however, this gets in your way, for example when you the module |
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296 | that calls C<EV::loop> (usually the main program) is not the same module |
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297 | as a long-living watcher (for example a DNS client module written by |
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298 | somebody else even). Then you might want any outstanding requests to be |
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299 | handled, but you would not want to keep C<EV::loop> from returning just |
|
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300 | because you happen to have this long-running UDP port watcher. |
|
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301 | |
|
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302 | In this case you can clear the keepalive status, which means that even |
|
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303 | though your watcher is active, it won't keep C<EV::loop> from returning. |
|
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304 | |
|
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305 | The initial value for keepalive is true (enabled), and you cna change it |
|
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306 | any time. |
|
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307 | |
|
|
308 | Example: Register an I/O watcher for some UDP socket but do not keep the |
|
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309 | event loop from running just because of that watcher. |
|
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310 | |
|
|
311 | my $udp_socket = ... |
|
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312 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
|
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313 | $udp_watcher->keepalive (0); |
|
|
314 | |
|
|
315 | =back |
|
|
316 | |
|
|
317 | |
|
|
318 | =head2 WATCHER TYPES |
|
|
319 | |
|
|
320 | Each of the following subsections describes a single watcher type. |
|
|
321 | |
|
|
322 | =head3 I/O WATCHERS - is this file descriptor readable or writable? |
|
|
323 | |
|
|
324 | =over 4 |
244 | |
325 | |
245 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
326 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
246 | |
327 | |
247 | =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
328 | =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
248 | |
329 | |
249 | As long as the returned watcher object is alive, call the C<$callback> |
330 | As long as the returned watcher object is alive, call the C<$callback> |
250 | when the events specified in C<$eventmask>. |
331 | when at least one of events specified in C<$eventmask> occurs. |
251 | |
332 | |
252 | The $eventmask can be one or more of these constants ORed together: |
333 | The $eventmask can be one or more of these constants ORed together: |
253 | |
334 | |
254 | EV::READ wait until read() wouldn't block anymore |
335 | EV::READ wait until read() wouldn't block anymore |
255 | EV::WRITE wait until write() wouldn't block anymore |
336 | EV::WRITE wait until write() wouldn't block anymore |
… | |
… | |
271 | |
352 | |
272 | =item $old_eventmask = $w->events ($new_eventmask) |
353 | =item $old_eventmask = $w->events ($new_eventmask) |
273 | |
354 | |
274 | Returns the previously set event mask and optionally set a new one. |
355 | Returns the previously set event mask and optionally set a new one. |
275 | |
356 | |
|
|
357 | =back |
|
|
358 | |
|
|
359 | |
|
|
360 | =head3 TIMER WATCHERS - relative and optionally repeating timeouts |
|
|
361 | |
|
|
362 | =over 4 |
276 | |
363 | |
277 | =item $w = EV::timer $after, $repeat, $callback |
364 | =item $w = EV::timer $after, $repeat, $callback |
278 | |
365 | |
279 | =item $w = EV::timer_ns $after, $repeat, $callback |
366 | =item $w = EV::timer_ns $after, $repeat, $callback |
280 | |
367 | |
281 | Calls the callback after C<$after> seconds. If C<$repeat> is non-zero, |
368 | Calls the callback after C<$after> seconds (which may be fractional). If |
282 | the timer will be restarted (with the $repeat value as $after) after the |
369 | C<$repeat> is non-zero, the timer will be restarted (with the $repeat |
283 | callback returns. |
370 | value as $after) after the callback returns. |
284 | |
371 | |
285 | This means that the callback would be called roughly after C<$after> |
372 | This means that the callback would be called roughly after C<$after> |
286 | seconds, and then every C<$repeat> seconds. The timer does his best not |
373 | seconds, and then every C<$repeat> seconds. The timer does his best not |
287 | to drift, but it will not invoke the timer more often then once per event |
374 | to drift, but it will not invoke the timer more often then once per event |
288 | loop iteration, and might drift in other cases. If that isn't acceptable, |
375 | loop iteration, and might drift in other cases. If that isn't acceptable, |
… | |
… | |
294 | |
381 | |
295 | The C<timer_ns> variant doesn't start (activate) the newly created watcher. |
382 | The C<timer_ns> variant doesn't start (activate) the newly created watcher. |
296 | |
383 | |
297 | =item $w->set ($after, $repeat) |
384 | =item $w->set ($after, $repeat) |
298 | |
385 | |
299 | Reconfigures the watcher, see the constructor above for details. Can be at |
386 | Reconfigures the watcher, see the constructor above for details. Can be called at |
300 | any time. |
387 | any time. |
301 | |
388 | |
302 | =item $w->again |
389 | =item $w->again |
303 | |
390 | |
304 | Similar to the C<start> method, but has special semantics for repeating timers: |
391 | Similar to the C<start> method, but has special semantics for repeating timers: |
… | |
… | |
315 | This behaviour is useful when you have a timeout for some IO |
402 | This behaviour is useful when you have a timeout for some IO |
316 | operation. You create a timer object with the same value for C<$after> and |
403 | operation. You create a timer object with the same value for C<$after> and |
317 | C<$repeat>, and then, in the read/write watcher, run the C<again> method |
404 | C<$repeat>, and then, in the read/write watcher, run the C<again> method |
318 | on the timeout. |
405 | on the timeout. |
319 | |
406 | |
|
|
407 | =back |
|
|
408 | |
|
|
409 | |
|
|
410 | =head3 PERIODIC WATCHERS - to cron or not to cron? |
|
|
411 | |
|
|
412 | =over 4 |
320 | |
413 | |
321 | =item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
414 | =item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
322 | |
415 | |
323 | =item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
416 | =item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
324 | |
417 | |
… | |
… | |
396 | |
489 | |
397 | The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
490 | The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
398 | |
491 | |
399 | =item $w->set ($at, $interval, $reschedule_cb) |
492 | =item $w->set ($at, $interval, $reschedule_cb) |
400 | |
493 | |
401 | Reconfigures the watcher, see the constructor above for details. Can be at |
494 | Reconfigures the watcher, see the constructor above for details. Can be called at |
402 | any time. |
495 | any time. |
403 | |
496 | |
404 | =item $w->again |
497 | =item $w->again |
405 | |
498 | |
406 | Simply stops and starts the watcher again. |
499 | Simply stops and starts the watcher again. |
407 | |
500 | |
|
|
501 | =item $time = $w->at |
|
|
502 | |
|
|
503 | Return the time that the watcher is expected to trigger next. |
|
|
504 | |
|
|
505 | =back |
|
|
506 | |
|
|
507 | |
|
|
508 | =head3 SIGNAL WATCHERS - signal me when a signal gets signalled! |
|
|
509 | |
|
|
510 | =over 4 |
408 | |
511 | |
409 | =item $w = EV::signal $signal, $callback |
512 | =item $w = EV::signal $signal, $callback |
410 | |
513 | |
411 | =item $w = EV::signal_ns $signal, $callback |
514 | =item $w = EV::signal_ns $signal, $callback |
412 | |
515 | |
413 | Call the callback when $signal is received (the signal can be specified |
516 | Call the callback when $signal is received (the signal can be specified by |
414 | by number or by name, just as with kill or %SIG). |
517 | number or by name, just as with C<kill> or C<%SIG>). |
415 | |
518 | |
416 | EV will grab the signal for the process (the kernel only allows one |
519 | EV will grab the signal for the process (the kernel only allows one |
417 | component to receive a signal at a time) when you start a signal watcher, |
520 | component to receive a signal at a time) when you start a signal watcher, |
418 | and removes it again when you stop it. Perl does the same when you |
521 | and removes it again when you stop it. Perl does the same when you |
419 | add/remove callbacks to %SIG, so watch out. |
522 | add/remove callbacks to C<%SIG>, so watch out. |
420 | |
523 | |
421 | You can have as many signal watchers per signal as you want. |
524 | You can have as many signal watchers per signal as you want. |
422 | |
525 | |
423 | The C<signal_ns> variant doesn't start (activate) the newly created watcher. |
526 | The C<signal_ns> variant doesn't start (activate) the newly created watcher. |
424 | |
527 | |
425 | =item $w->set ($signal) |
528 | =item $w->set ($signal) |
426 | |
529 | |
427 | Reconfigures the watcher, see the constructor above for details. Can be at |
530 | Reconfigures the watcher, see the constructor above for details. Can be |
428 | any time. |
531 | called at any time. |
429 | |
532 | |
430 | =item $current_signum = $w->signal |
533 | =item $current_signum = $w->signal |
431 | |
534 | |
432 | =item $old_signum = $w->signal ($new_signal) |
535 | =item $old_signum = $w->signal ($new_signal) |
433 | |
536 | |
434 | Returns the previously set signal (always as a number not name) and |
537 | Returns the previously set signal (always as a number not name) and |
435 | optionally set a new one. |
538 | optionally set a new one. |
436 | |
539 | |
|
|
540 | =back |
|
|
541 | |
|
|
542 | |
|
|
543 | =head3 CHILD WATCHERS - watch out for process status changes |
|
|
544 | |
|
|
545 | =over 4 |
437 | |
546 | |
438 | =item $w = EV::child $pid, $callback |
547 | =item $w = EV::child $pid, $callback |
439 | |
548 | |
440 | =item $w = EV::child_ns $pid, $callback |
549 | =item $w = EV::child_ns $pid, $callback |
441 | |
550 | |
442 | Call the callback when a status change for pid C<$pid> (or any pid |
551 | Call the callback when a status change for pid C<$pid> (or any pid if |
443 | if C<$pid> is 0) has been received. More precisely: when the process |
552 | C<$pid> is 0) has been received. More precisely: when the process receives |
444 | receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all |
553 | a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all |
445 | changed/zombie children and call the callback. |
554 | changed/zombie children and call the callback. |
446 | |
555 | |
447 | You can access both status and pid by using the C<rstatus> and C<rpid> |
556 | It is valid (and fully supported) to install a child watcher after a child |
448 | methods on the watcher object. |
557 | has exited but before the event loop has started its next iteration (for |
|
|
558 | example, first you C<fork>, then the new child process might exit, and |
|
|
559 | only then do you install a child watcher in the parent for the new pid). |
449 | |
560 | |
|
|
561 | You can access both exit (or tracing) status and pid by using the |
|
|
562 | C<rstatus> and C<rpid> methods on the watcher object. |
|
|
563 | |
450 | You can have as many pid watchers per pid as you want. |
564 | You can have as many pid watchers per pid as you want, they will all be |
|
|
565 | called. |
451 | |
566 | |
452 | The C<child_ns> variant doesn't start (activate) the newly created watcher. |
567 | The C<child_ns> variant doesn't start (activate) the newly created watcher. |
453 | |
568 | |
454 | =item $w->set ($pid) |
569 | =item $w->set ($pid) |
455 | |
570 | |
456 | Reconfigures the watcher, see the constructor above for details. Can be at |
571 | Reconfigures the watcher, see the constructor above for details. Can be called at |
457 | any time. |
572 | any time. |
458 | |
573 | |
459 | =item $current_pid = $w->pid |
574 | =item $current_pid = $w->pid |
460 | |
575 | |
461 | =item $old_pid = $w->pid ($new_pid) |
576 | =item $old_pid = $w->pid ($new_pid) |
… | |
… | |
470 | =item $pid = $w->rpid |
585 | =item $pid = $w->rpid |
471 | |
586 | |
472 | Return the pid of the awaited child (useful when you have installed a |
587 | Return the pid of the awaited child (useful when you have installed a |
473 | watcher for all pids). |
588 | watcher for all pids). |
474 | |
589 | |
|
|
590 | =back |
|
|
591 | |
|
|
592 | |
|
|
593 | =head3 STAT WATCHERS - did the file attributes just change? |
|
|
594 | |
|
|
595 | =over 4 |
|
|
596 | |
|
|
597 | =item $w = EV::stat $path, $interval, $callback |
|
|
598 | |
|
|
599 | =item $w = EV::stat_ns $path, $interval, $callback |
|
|
600 | |
|
|
601 | Call the callback when a file status change has been detected on |
|
|
602 | C<$path>. The C<$path> does not need to exist, changing from "path exists" |
|
|
603 | to "path does not exist" is a status change like any other. |
|
|
604 | |
|
|
605 | The C<$interval> is a recommended polling interval for systems where |
|
|
606 | OS-supported change notifications don't exist or are not supported. If |
|
|
607 | you use C<0> then an unspecified default is used (which is highly |
|
|
608 | recommended!), which is to be expected to be around five seconds usually. |
|
|
609 | |
|
|
610 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
611 | as even with OS-supported change notifications, this can be |
|
|
612 | resource-intensive. |
|
|
613 | |
|
|
614 | The C<stat_ns> variant doesn't start (activate) the newly created watcher. |
|
|
615 | |
|
|
616 | =item ... = $w->stat |
|
|
617 | |
|
|
618 | This call is very similar to the perl C<stat> built-in: It stats (using |
|
|
619 | C<lstat>) the path specified in the watcher and sets perls stat cache (as |
|
|
620 | well as EV's idea of the current stat values) to the values found. |
|
|
621 | |
|
|
622 | In scalar context, a boolean is return indicating success or failure of |
|
|
623 | the stat. In list context, the same 13-value list as with stat is returned |
|
|
624 | (except that the blksize and blocks fields are not reliable). |
|
|
625 | |
|
|
626 | In the case of an error, errno is set to C<ENOENT> (regardless of the |
|
|
627 | actual error value) and the C<nlink> value is forced to zero (if the stat |
|
|
628 | was successful then nlink is guaranteed to be non-zero). |
|
|
629 | |
|
|
630 | See also the next two entries for more info. |
|
|
631 | |
|
|
632 | =item ... = $w->attr |
|
|
633 | |
|
|
634 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
|
|
635 | the values most recently detected by EV. See the next entry for more info. |
|
|
636 | |
|
|
637 | =item ... = $w->prev |
|
|
638 | |
|
|
639 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
|
|
640 | the previous set of values, before the change. |
|
|
641 | |
|
|
642 | That is, when the watcher callback is invoked, C<< $w->prev >> will be set |
|
|
643 | to the values found I<before> a change was detected, while C<< $w->attr >> |
|
|
644 | returns the values found leading to the change detection. The difference (if any) |
|
|
645 | between C<prev> and C<attr> is what triggered the callback. |
|
|
646 | |
|
|
647 | If you did something to the filesystem object and do not want to trigger |
|
|
648 | yet another change, you can call C<stat> to update EV's idea of what the |
|
|
649 | current attributes are. |
|
|
650 | |
|
|
651 | =item $w->set ($path, $interval) |
|
|
652 | |
|
|
653 | Reconfigures the watcher, see the constructor above for details. Can be |
|
|
654 | called at any time. |
|
|
655 | |
|
|
656 | =item $current_path = $w->path |
|
|
657 | |
|
|
658 | =item $old_path = $w->path ($new_path) |
|
|
659 | |
|
|
660 | Returns the previously set path and optionally set a new one. |
|
|
661 | |
|
|
662 | =item $current_interval = $w->interval |
|
|
663 | |
|
|
664 | =item $old_interval = $w->interval ($new_interval) |
|
|
665 | |
|
|
666 | Returns the previously set interval and optionally set a new one. Can be |
|
|
667 | used to query the actual interval used. |
|
|
668 | |
|
|
669 | =back |
|
|
670 | |
|
|
671 | |
|
|
672 | =head3 IDLE WATCHERS - when you've got nothing better to do... |
|
|
673 | |
|
|
674 | =over 4 |
475 | |
675 | |
476 | =item $w = EV::idle $callback |
676 | =item $w = EV::idle $callback |
477 | |
677 | |
478 | =item $w = EV::idle_ns $callback |
678 | =item $w = EV::idle_ns $callback |
479 | |
679 | |
480 | Call the callback when there are no pending io, timer/periodic, signal or |
680 | Call the callback when there are no other pending watchers of the same or |
481 | child events, i.e. when the process is idle. |
681 | higher priority (excluding check, prepare and other idle watchers of the |
|
|
682 | same or lower priority, of course). They are called idle watchers because |
|
|
683 | when the watcher is the highest priority pending event in the process, the |
|
|
684 | process is considered to be idle at that priority. |
|
|
685 | |
|
|
686 | If you want a watcher that is only ever called when I<no> other events are |
|
|
687 | outstanding you have to set the priority to C<EV::MINPRI>. |
482 | |
688 | |
483 | The process will not block as long as any idle watchers are active, and |
689 | The process will not block as long as any idle watchers are active, and |
484 | they will be called repeatedly until stopped. |
690 | they will be called repeatedly until stopped. |
485 | |
691 | |
|
|
692 | For example, if you have idle watchers at priority C<0> and C<1>, and |
|
|
693 | an I/O watcher at priority C<0>, then the idle watcher at priority C<1> |
|
|
694 | and the I/O watcher will always run when ready. Only when the idle watcher |
|
|
695 | at priority C<1> is stopped and the I/O watcher at priority C<0> is not |
|
|
696 | pending with the C<0>-priority idle watcher be invoked. |
|
|
697 | |
486 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
698 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
487 | |
699 | |
|
|
700 | =back |
|
|
701 | |
|
|
702 | |
|
|
703 | =head3 PREPARE WATCHERS - customise your event loop! |
|
|
704 | |
|
|
705 | =over 4 |
488 | |
706 | |
489 | =item $w = EV::prepare $callback |
707 | =item $w = EV::prepare $callback |
490 | |
708 | |
491 | =item $w = EV::prepare_ns $callback |
709 | =item $w = EV::prepare_ns $callback |
492 | |
710 | |
… | |
… | |
495 | |
713 | |
496 | See the EV::check watcher, below, for explanations and an example. |
714 | See the EV::check watcher, below, for explanations and an example. |
497 | |
715 | |
498 | The C<prepare_ns> variant doesn't start (activate) the newly created watcher. |
716 | The C<prepare_ns> variant doesn't start (activate) the newly created watcher. |
499 | |
717 | |
|
|
718 | =back |
|
|
719 | |
|
|
720 | |
|
|
721 | =head3 CHECK WATCHERS - customise your event loop even more! |
|
|
722 | |
|
|
723 | =over 4 |
500 | |
724 | |
501 | =item $w = EV::check $callback |
725 | =item $w = EV::check $callback |
502 | |
726 | |
503 | =item $w = EV::check_ns $callback |
727 | =item $w = EV::check_ns $callback |
504 | |
728 | |
… | |
… | |
518 | or return; |
742 | or return; |
519 | |
743 | |
520 | # make the dispatcher handle any outstanding stuff |
744 | # make the dispatcher handle any outstanding stuff |
521 | ... not shown |
745 | ... not shown |
522 | |
746 | |
523 | # create an IO watcher for each and every socket |
747 | # create an I/O watcher for each and every socket |
524 | @snmp_watcher = ( |
748 | @snmp_watcher = ( |
525 | (map { EV::io $_, EV::READ, sub { } } |
749 | (map { EV::io $_, EV::READ, sub { } } |
526 | keys %{ $dispatcher->{_descriptors} }), |
750 | keys %{ $dispatcher->{_descriptors} }), |
527 | |
751 | |
528 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
752 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
… | |
… | |
549 | first). |
773 | first). |
550 | |
774 | |
551 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
775 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
552 | |
776 | |
553 | =back |
777 | =back |
|
|
778 | |
|
|
779 | |
|
|
780 | =head3 FORK WATCHERS - the audacity to resume the event loop after a fork |
|
|
781 | |
|
|
782 | Fork watchers are called when a C<fork ()> was detected. The invocation |
|
|
783 | is done before the event loop blocks next and before C<check> watchers |
|
|
784 | are being called, and only in the child after the fork. |
|
|
785 | |
|
|
786 | =over 4 |
|
|
787 | |
|
|
788 | =item $w = EV::fork $callback |
|
|
789 | |
|
|
790 | =item $w = EV::fork_ns $callback |
|
|
791 | |
|
|
792 | Call the callback before the event loop is resumed in the child process |
|
|
793 | after a fork. |
|
|
794 | |
|
|
795 | The C<fork_ns> variant doesn't start (activate) the newly created watcher. |
|
|
796 | |
|
|
797 | =back |
|
|
798 | |
|
|
799 | |
|
|
800 | =head1 PERL SIGNALS |
|
|
801 | |
|
|
802 | While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour |
|
|
803 | with EV is as the same as any other C library: Perl-signals will only be |
|
|
804 | handled when Perl runs, which means your signal handler might be invoked |
|
|
805 | only the next time an event callback is invoked. |
|
|
806 | |
|
|
807 | The solution is to use EV signal watchers (see C<EV::signal>), which will |
|
|
808 | ensure proper operations with regards to other event watchers. |
|
|
809 | |
|
|
810 | If you cannot do this for whatever reason, you can also force a watcher |
|
|
811 | to be called on every event loop iteration by installing a C<EV::check> |
|
|
812 | watcher: |
|
|
813 | |
|
|
814 | my $async_check = EV::check sub { }; |
|
|
815 | |
|
|
816 | This ensures that perl shortly gets into control for a short time, and |
|
|
817 | also ensures slower overall operation. |
554 | |
818 | |
555 | =head1 THREADS |
819 | =head1 THREADS |
556 | |
820 | |
557 | Threads are not supported by this module in any way. Perl pseudo-threads |
821 | Threads are not supported by this module in any way. Perl pseudo-threads |
558 | is evil stuff and must die. As soon as Perl gains real threads I will work |
822 | is evil stuff and must die. As soon as Perl gains real threads I will work |
… | |
… | |
580 | our $DIED = sub { |
844 | our $DIED = sub { |
581 | warn "EV: error in callback (ignoring): $@"; |
845 | warn "EV: error in callback (ignoring): $@"; |
582 | }; |
846 | }; |
583 | |
847 | |
584 | default_loop |
848 | default_loop |
585 | or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; |
849 | or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?'; |
586 | |
850 | |
587 | 1; |
851 | 1; |
588 | |
852 | |
589 | =head1 SEE ALSO |
853 | =head1 SEE ALSO |
590 | |
854 | |
591 | L<EV::DNS>. |
855 | L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as |
|
|
856 | event loop), L<Coro::EV> (efficient coroutines with EV). |
592 | |
857 | |
593 | =head1 AUTHOR |
858 | =head1 AUTHOR |
594 | |
859 | |
595 | Marc Lehmann <schmorp@schmorp.de> |
860 | Marc Lehmann <schmorp@schmorp.de> |
596 | http://home.schmorp.de/ |
861 | http://home.schmorp.de/ |