… | |
… | |
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"; |
|
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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 = '1.0'; |
73 | our $VERSION = '1.8'; |
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 = |
|
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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"; |
75 | |
90 | |
76 | =head1 BASIC INTERFACE |
91 | =head1 BASIC INTERFACE |
77 | |
92 | |
78 | =over 4 |
93 | =over 4 |
79 | |
94 | |
… | |
… | |
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 | |
|
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139 | Return the number of times the event loop has polled for new |
|
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140 | events. Sometiems useful as a generation counter. |
|
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141 | |
|
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142 | =item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
|
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143 | |
|
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144 | This function rolls together an I/O and a timer watcher for a single |
|
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145 | one-shot event without the need for managing a watcher object. |
|
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146 | |
|
|
147 | If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> |
|
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148 | must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ |
|
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149 | | EV::WRITE>, indicating the type of I/O event you want to wait for. If |
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150 | you do not want to wait for some I/O event, specify C<undef> for |
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151 | C<$fh_or_undef> and C<0> for C<$events>). |
|
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152 | |
|
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153 | If timeout is C<undef> or negative, then there will be no |
|
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154 | timeout. Otherwise a EV::timer with this value will be started. |
|
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155 | |
|
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156 | When an error occurs or either the timeout or I/O watcher triggers, then |
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157 | the callback will be called with the received event set (in general |
|
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158 | you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>, |
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159 | C<EV::WRITE> and C<EV::TIMEOUT>). |
|
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160 | |
|
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161 | EV::once doesn't return anything: the watchers stay active till either |
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162 | of them triggers, then they will be stopped and freed, and the callback |
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163 | invoked. |
|
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164 | |
|
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165 | =back |
|
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166 | |
124 | =head2 WATCHER |
167 | =head2 WATCHER OBJECTS |
125 | |
168 | |
126 | A watcher is an object that gets created to record your interest in some |
169 | 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 |
170 | event. For instance, if you want to wait for STDIN to become readable, you |
128 | would create an EV::io watcher for that: |
171 | would create an EV::io watcher for that: |
129 | |
172 | |
… | |
… | |
138 | events. |
181 | events. |
139 | |
182 | |
140 | Each watcher type has its associated bit in revents, so you can use the |
183 | 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 |
184 | 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, |
185 | 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 |
186 | 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 |
187 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
145 | uses EV::TIMEOUT). |
188 | uses EV::TIMEOUT). |
146 | |
189 | |
147 | In the rare case where one wants to create a watcher but not start it at |
190 | 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 |
191 | the same time, each constructor has a variant with a trailing C<_ns> in |
… | |
… | |
154 | |
197 | |
155 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
198 | 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, |
199 | ->fh and so on) automatically stop and start it again if it is active, |
157 | which means pending events get lost. |
200 | which means pending events get lost. |
158 | |
201 | |
159 | =head2 WATCHER TYPES |
202 | =head2 COMMON WATCHER METHODS |
160 | |
203 | |
161 | Now lets move to the existing watcher types and asociated methods. |
204 | This section lists methods common to all watchers. |
162 | |
|
|
163 | The following methods are available for all watchers. Then followes a |
|
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164 | description of each watcher constructor (EV::io, EV::timer, EV::periodic, |
|
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165 | EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by |
|
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166 | any type-specific methods (if any). |
|
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167 | |
205 | |
168 | =over 4 |
206 | =over 4 |
169 | |
207 | |
170 | =item $w->start |
208 | =item $w->start |
171 | |
209 | |
… | |
… | |
175 | |
213 | |
176 | =item $w->stop |
214 | =item $w->stop |
177 | |
215 | |
178 | Stop a watcher if it is active. Also clear any pending events (events that |
216 | 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), |
217 | have been received but that didn't yet result in a callback invocation), |
180 | regardless of wether the watcher was active or not. |
218 | regardless of whether the watcher was active or not. |
181 | |
219 | |
182 | =item $bool = $w->is_active |
220 | =item $bool = $w->is_active |
183 | |
221 | |
184 | Returns true if the watcher is active, false otherwise. |
222 | Returns true if the watcher is active, false otherwise. |
185 | |
223 | |
… | |
… | |
210 | watchers with higher priority will be invoked first. The valid range of |
248 | watchers with higher priority will be invoked first. The valid range of |
211 | priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default |
249 | priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default |
212 | -2). If the priority is outside this range it will automatically be |
250 | -2). If the priority is outside this range it will automatically be |
213 | normalised to the nearest valid priority. |
251 | normalised to the nearest valid priority. |
214 | |
252 | |
215 | The default priority of any newly-created weatcher is 0. |
253 | The default priority of any newly-created watcher is 0. |
|
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254 | |
|
|
255 | Note that the priority semantics have not yet been fleshed out and are |
|
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256 | subject to almost certain change. |
216 | |
257 | |
217 | =item $w->trigger ($revents) |
258 | =item $w->trigger ($revents) |
218 | |
259 | |
219 | Call the callback *now* with the given event mask. |
260 | Call the callback *now* with the given event mask. |
220 | |
261 | |
|
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262 | =item $previous_state = $w->keepalive ($bool) |
|
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263 | |
|
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264 | Normally, C<EV::loop> will return when there are no active watchers |
|
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265 | (which is a "deadlock" because no progress can be made anymore). This is |
|
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266 | convinient because it allows you to start your watchers (and your jobs), |
|
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267 | call C<EV::loop> once and when it returns you know that all your jobs are |
|
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268 | finished (or they forgot to register some watchers for their task :). |
|
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269 | |
|
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270 | Sometimes, however, this gets in your way, for example when you the module |
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271 | that calls C<EV::loop> (usually the main program) is not the same module |
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272 | as a long-living watcher (for example a DNS client module written by |
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273 | somebody else even). Then you might want any outstanding requests to be |
|
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274 | handled, but you would not want to keep C<EV::loop> from returning just |
|
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275 | because you happen to have this long-running UDP port watcher. |
|
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276 | |
|
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277 | In this case you can clear the keepalive status, which means that even |
|
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278 | though your watcher is active, it won't keep C<EV::loop> from returning. |
|
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279 | |
|
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280 | The initial value for keepalive is true (enabled), and you cna change it |
|
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281 | any time. |
|
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282 | |
|
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283 | Example: Register an I/O watcher for some UDP socket but do not keep the |
|
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284 | event loop from running just because of that watcher. |
|
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285 | |
|
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286 | my $udp_socket = ... |
|
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287 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
|
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288 | $udp_watcher->keepalive (0); |
|
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289 | |
|
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290 | =back |
|
|
291 | |
|
|
292 | |
|
|
293 | =head2 WATCHER TYPES |
|
|
294 | |
|
|
295 | Each of the following subsections describes a single watcher type. |
|
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296 | |
|
|
297 | =head3 I/O WATCHERS - is this file descriptor readable or writable? |
|
|
298 | |
|
|
299 | =over 4 |
221 | |
300 | |
222 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
301 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
223 | |
302 | |
224 | =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
303 | =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
225 | |
304 | |
226 | As long as the returned watcher object is alive, call the C<$callback> |
305 | As long as the returned watcher object is alive, call the C<$callback> |
227 | when the events specified in C<$eventmask>. |
306 | when at least one of events specified in C<$eventmask> occurs. |
228 | |
307 | |
229 | The $eventmask can be one or more of these constants ORed together: |
308 | The $eventmask can be one or more of these constants ORed together: |
230 | |
309 | |
231 | EV::READ wait until read() wouldn't block anymore |
310 | EV::READ wait until read() wouldn't block anymore |
232 | EV::WRITE wait until write() wouldn't block anymore |
311 | EV::WRITE wait until write() wouldn't block anymore |
… | |
… | |
248 | |
327 | |
249 | =item $old_eventmask = $w->events ($new_eventmask) |
328 | =item $old_eventmask = $w->events ($new_eventmask) |
250 | |
329 | |
251 | Returns the previously set event mask and optionally set a new one. |
330 | Returns the previously set event mask and optionally set a new one. |
252 | |
331 | |
|
|
332 | =back |
|
|
333 | |
|
|
334 | |
|
|
335 | =head3 TIMER WATCHERS - relative and optionally repeating timeouts |
|
|
336 | |
|
|
337 | =over 4 |
253 | |
338 | |
254 | =item $w = EV::timer $after, $repeat, $callback |
339 | =item $w = EV::timer $after, $repeat, $callback |
255 | |
340 | |
256 | =item $w = EV::timer_ns $after, $repeat, $callback |
341 | =item $w = EV::timer_ns $after, $repeat, $callback |
257 | |
342 | |
258 | Calls the callback after C<$after> seconds. If C<$repeat> is non-zero, |
343 | Calls the callback after C<$after> seconds (which may be fractional). If |
259 | the timer will be restarted (with the $repeat value as $after) after the |
344 | C<$repeat> is non-zero, the timer will be restarted (with the $repeat |
260 | callback returns. |
345 | value as $after) after the callback returns. |
261 | |
346 | |
262 | This means that the callback would be called roughly after C<$after> |
347 | 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 |
348 | 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 |
349 | 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, |
350 | loop iteration, and might drift in other cases. If that isn't acceptable, |
… | |
… | |
271 | |
356 | |
272 | The C<timer_ns> variant doesn't start (activate) the newly created watcher. |
357 | The C<timer_ns> variant doesn't start (activate) the newly created watcher. |
273 | |
358 | |
274 | =item $w->set ($after, $repeat) |
359 | =item $w->set ($after, $repeat) |
275 | |
360 | |
276 | Reconfigures the watcher, see the constructor above for details. Can be at |
361 | Reconfigures the watcher, see the constructor above for details. Can be called at |
277 | any time. |
362 | any time. |
278 | |
363 | |
279 | =item $w->again |
364 | =item $w->again |
280 | |
365 | |
281 | Similar to the C<start> method, but has special semantics for repeating timers: |
366 | Similar to the C<start> method, but has special semantics for repeating timers: |
… | |
… | |
292 | This behaviour is useful when you have a timeout for some IO |
377 | This behaviour is useful when you have a timeout for some IO |
293 | operation. You create a timer object with the same value for C<$after> and |
378 | 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 |
379 | C<$repeat>, and then, in the read/write watcher, run the C<again> method |
295 | on the timeout. |
380 | on the timeout. |
296 | |
381 | |
|
|
382 | =back |
|
|
383 | |
|
|
384 | |
|
|
385 | =head3 PERIODIC WATCHERS - to cron or not to cron? |
|
|
386 | |
|
|
387 | =over 4 |
297 | |
388 | |
298 | =item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
389 | =item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
299 | |
390 | |
300 | =item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
391 | =item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
301 | |
392 | |
… | |
… | |
373 | |
464 | |
374 | The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
465 | The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
375 | |
466 | |
376 | =item $w->set ($at, $interval, $reschedule_cb) |
467 | =item $w->set ($at, $interval, $reschedule_cb) |
377 | |
468 | |
378 | Reconfigures the watcher, see the constructor above for details. Can be at |
469 | Reconfigures the watcher, see the constructor above for details. Can be called at |
379 | any time. |
470 | any time. |
380 | |
471 | |
381 | =item $w->again |
472 | =item $w->again |
382 | |
473 | |
383 | Simply stops and starts the watcher again. |
474 | Simply stops and starts the watcher again. |
384 | |
475 | |
|
|
476 | =back |
|
|
477 | |
|
|
478 | |
|
|
479 | =head3 SIGNAL WATCHERS - signal me when a signal gets signalled! |
|
|
480 | |
|
|
481 | =over 4 |
385 | |
482 | |
386 | =item $w = EV::signal $signal, $callback |
483 | =item $w = EV::signal $signal, $callback |
387 | |
484 | |
388 | =item $w = EV::signal_ns $signal, $callback |
485 | =item $w = EV::signal_ns $signal, $callback |
389 | |
486 | |
390 | Call the callback when $signal is received (the signal can be specified |
487 | 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). |
488 | number or by name, just as with C<kill> or C<%SIG>). |
392 | |
489 | |
393 | EV will grab the signal for the process (the kernel only allows one |
490 | 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, |
491 | 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 |
492 | and removes it again when you stop it. Perl does the same when you |
396 | add/remove callbacks to %SIG, so watch out. |
493 | add/remove callbacks to C<%SIG>, so watch out. |
397 | |
494 | |
398 | You can have as many signal watchers per signal as you want. |
495 | You can have as many signal watchers per signal as you want. |
399 | |
496 | |
400 | The C<signal_ns> variant doesn't start (activate) the newly created watcher. |
497 | The C<signal_ns> variant doesn't start (activate) the newly created watcher. |
401 | |
498 | |
402 | =item $w->set ($signal) |
499 | =item $w->set ($signal) |
403 | |
500 | |
404 | Reconfigures the watcher, see the constructor above for details. Can be at |
501 | Reconfigures the watcher, see the constructor above for details. Can be |
405 | any time. |
502 | called at any time. |
406 | |
503 | |
407 | =item $current_signum = $w->signal |
504 | =item $current_signum = $w->signal |
408 | |
505 | |
409 | =item $old_signum = $w->signal ($new_signal) |
506 | =item $old_signum = $w->signal ($new_signal) |
410 | |
507 | |
411 | Returns the previously set signal (always as a number not name) and |
508 | Returns the previously set signal (always as a number not name) and |
412 | optionally set a new one. |
509 | optionally set a new one. |
413 | |
510 | |
|
|
511 | =back |
|
|
512 | |
|
|
513 | |
|
|
514 | =head3 CHILD WATCHERS - watch out for process status changes |
|
|
515 | |
|
|
516 | =over 4 |
414 | |
517 | |
415 | =item $w = EV::child $pid, $callback |
518 | =item $w = EV::child $pid, $callback |
416 | |
519 | |
417 | =item $w = EV::child_ns $pid, $callback |
520 | =item $w = EV::child_ns $pid, $callback |
418 | |
521 | |
419 | Call the callback when a status change for pid C<$pid> (or any pid |
522 | 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 |
523 | 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 |
524 | a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all |
422 | changed/zombie children and call the callback. |
525 | changed/zombie children and call the callback. |
423 | |
526 | |
424 | You can access both status and pid by using the C<rstatus> and C<rpid> |
527 | It is valid (and fully supported) to install a child watcher after a child |
425 | methods on the watcher object. |
528 | has exited but before the event loop has started its next iteration (for |
|
|
529 | example, first you C<fork>, then the new child process might exit, and |
|
|
530 | only then do you install a child watcher in the parent for the new pid). |
426 | |
531 | |
|
|
532 | You can access both exit (or tracing) status and pid by using the |
|
|
533 | C<rstatus> and C<rpid> methods on the watcher object. |
|
|
534 | |
427 | You can have as many pid watchers per pid as you want. |
535 | You can have as many pid watchers per pid as you want, they will all be |
|
|
536 | called. |
428 | |
537 | |
429 | The C<child_ns> variant doesn't start (activate) the newly created watcher. |
538 | The C<child_ns> variant doesn't start (activate) the newly created watcher. |
430 | |
539 | |
431 | =item $w->set ($pid) |
540 | =item $w->set ($pid) |
432 | |
541 | |
433 | Reconfigures the watcher, see the constructor above for details. Can be at |
542 | Reconfigures the watcher, see the constructor above for details. Can be called at |
434 | any time. |
543 | any time. |
435 | |
544 | |
436 | =item $current_pid = $w->pid |
545 | =item $current_pid = $w->pid |
437 | |
546 | |
438 | =item $old_pid = $w->pid ($new_pid) |
547 | =item $old_pid = $w->pid ($new_pid) |
… | |
… | |
447 | =item $pid = $w->rpid |
556 | =item $pid = $w->rpid |
448 | |
557 | |
449 | Return the pid of the awaited child (useful when you have installed a |
558 | Return the pid of the awaited child (useful when you have installed a |
450 | watcher for all pids). |
559 | watcher for all pids). |
451 | |
560 | |
|
|
561 | =back |
|
|
562 | |
|
|
563 | |
|
|
564 | =head3 STAT WATCHERS - did the file attributes just change? |
|
|
565 | |
|
|
566 | =over 4 |
|
|
567 | |
|
|
568 | =item $w = EV::stat $path, $interval, $callback |
|
|
569 | |
|
|
570 | =item $w = EV::stat_ns $path, $interval, $callback |
|
|
571 | |
|
|
572 | Call the callback when a file status change has been detected on |
|
|
573 | C<$path>. The C<$path> does not need to exist, changing from "path exists" |
|
|
574 | to "path does not exist" is a status change like any other. |
|
|
575 | |
|
|
576 | The C<$interval> is a recommended polling interval for systems where |
|
|
577 | OS-supported change notifications don't exist or are not supported. If |
|
|
578 | you use C<0> then an unspecified default is used (which is highly |
|
|
579 | recommended!), which is to be expected to be around five seconds usually. |
|
|
580 | |
|
|
581 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
582 | as even with OS-supported change notifications, this can be |
|
|
583 | resource-intensive. |
|
|
584 | |
|
|
585 | The C<stat_ns> variant doesn't start (activate) the newly created watcher. |
|
|
586 | |
|
|
587 | =item ... = $w->stat |
|
|
588 | |
|
|
589 | This call is very similar to the perl C<stat> built-in: It stats (using |
|
|
590 | C<lstat>) the path specified in the watcher and sets perls stat cache (as |
|
|
591 | well as EV's idea of the current stat values) to the values found. |
|
|
592 | |
|
|
593 | In scalar context, a boolean is return indicating success or failure of |
|
|
594 | the stat. In list context, the same 13-value list as with stat is returned |
|
|
595 | (except that the blksize and blocks fields are not reliable). |
|
|
596 | |
|
|
597 | In the case of an error, errno is set to C<ENOENT> (regardless of the |
|
|
598 | actual error value) and the C<nlink> value is forced to zero (if the stat |
|
|
599 | was successful then nlink is guaranteed to be non-zero). |
|
|
600 | |
|
|
601 | See also the next two entries for more info. |
|
|
602 | |
|
|
603 | =item ... = $w->attr |
|
|
604 | |
|
|
605 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
|
|
606 | the values most recently detected by EV. See the next entry for more info. |
|
|
607 | |
|
|
608 | =item ... = $w->prev |
|
|
609 | |
|
|
610 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
|
|
611 | the previous set of values, before the change. |
|
|
612 | |
|
|
613 | That is, when the watcher callback is invoked, C<< $w->prev >> will be set |
|
|
614 | to the values found I<before> a change was detected, while C<< $w->attr >> |
|
|
615 | returns the values found leading to the change detection. The difference (if any) |
|
|
616 | between C<prev> and C<attr> is what triggered the callback. |
|
|
617 | |
|
|
618 | If you did something to the filesystem object and do not want to trigger |
|
|
619 | yet another change, you can call C<stat> to update EV's idea of what the |
|
|
620 | current attributes are. |
|
|
621 | |
|
|
622 | =item $w->set ($path, $interval) |
|
|
623 | |
|
|
624 | Reconfigures the watcher, see the constructor above for details. Can be |
|
|
625 | called at any time. |
|
|
626 | |
|
|
627 | =item $current_path = $w->path |
|
|
628 | |
|
|
629 | =item $old_path = $w->path ($new_path) |
|
|
630 | |
|
|
631 | Returns the previously set path and optionally set a new one. |
|
|
632 | |
|
|
633 | =item $current_interval = $w->interval |
|
|
634 | |
|
|
635 | =item $old_interval = $w->interval ($new_interval) |
|
|
636 | |
|
|
637 | Returns the previously set interval and optionally set a new one. Can be |
|
|
638 | used to query the actual interval used. |
|
|
639 | |
|
|
640 | =back |
|
|
641 | |
|
|
642 | |
|
|
643 | =head3 IDLE WATCHERS - when you've got nothing better to do... |
|
|
644 | |
|
|
645 | =over 4 |
452 | |
646 | |
453 | =item $w = EV::idle $callback |
647 | =item $w = EV::idle $callback |
454 | |
648 | |
455 | =item $w = EV::idle_ns $callback |
649 | =item $w = EV::idle_ns $callback |
456 | |
650 | |
457 | Call the callback when there are no pending io, timer/periodic, signal or |
651 | Call the callback when there are no other pending watchers of the same or |
458 | child events, i.e. when the process is idle. |
652 | higher priority (excluding check, prepare and other idle watchers of the |
|
|
653 | same or lower priority, of course). They are called idle watchers because |
|
|
654 | when the watcher is the highest priority pending event in the process, the |
|
|
655 | process is considered to be idle at that priority. |
|
|
656 | |
|
|
657 | If you want a watcher that is only ever called when I<no> other events are |
|
|
658 | outstanding you have to set the priority to C<EV::MINPRI>. |
459 | |
659 | |
460 | The process will not block as long as any idle watchers are active, and |
660 | The process will not block as long as any idle watchers are active, and |
461 | they will be called repeatedly until stopped. |
661 | they will be called repeatedly until stopped. |
462 | |
662 | |
|
|
663 | For example, if you have idle watchers at priority C<0> and C<1>, and |
|
|
664 | an I/O watcher at priority C<0>, then the idle watcher at priority C<1> |
|
|
665 | and the I/O watcher will always run when ready. Only when the idle watcher |
|
|
666 | at priority C<1> is stopped and the I/O watcher at priority C<0> is not |
|
|
667 | pending with the C<0>-priority idle watcher be invoked. |
|
|
668 | |
463 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
669 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
464 | |
670 | |
|
|
671 | =back |
|
|
672 | |
|
|
673 | |
|
|
674 | =head3 PREPARE WATCHERS - customise your event loop! |
|
|
675 | |
|
|
676 | =over 4 |
465 | |
677 | |
466 | =item $w = EV::prepare $callback |
678 | =item $w = EV::prepare $callback |
467 | |
679 | |
468 | =item $w = EV::prepare_ns $callback |
680 | =item $w = EV::prepare_ns $callback |
469 | |
681 | |
… | |
… | |
472 | |
684 | |
473 | See the EV::check watcher, below, for explanations and an example. |
685 | See the EV::check watcher, below, for explanations and an example. |
474 | |
686 | |
475 | The C<prepare_ns> variant doesn't start (activate) the newly created watcher. |
687 | The C<prepare_ns> variant doesn't start (activate) the newly created watcher. |
476 | |
688 | |
|
|
689 | =back |
|
|
690 | |
|
|
691 | |
|
|
692 | =head3 CHECK WATCHERS - customise your event loop even more! |
|
|
693 | |
|
|
694 | =over 4 |
477 | |
695 | |
478 | =item $w = EV::check $callback |
696 | =item $w = EV::check $callback |
479 | |
697 | |
480 | =item $w = EV::check_ns $callback |
698 | =item $w = EV::check_ns $callback |
481 | |
699 | |
… | |
… | |
493 | # do nothing unless active |
711 | # do nothing unless active |
494 | $dispatcher->{_event_queue_h} |
712 | $dispatcher->{_event_queue_h} |
495 | or return; |
713 | or return; |
496 | |
714 | |
497 | # make the dispatcher handle any outstanding stuff |
715 | # make the dispatcher handle any outstanding stuff |
|
|
716 | ... not shown |
498 | |
717 | |
499 | # create an IO watcher for each and every socket |
718 | # create an I/O watcher for each and every socket |
500 | @snmp_watcher = ( |
719 | @snmp_watcher = ( |
501 | (map { EV::io $_, EV::READ, sub { } } |
720 | (map { EV::io $_, EV::READ, sub { } } |
502 | keys %{ $dispatcher->{_descriptors} }), |
721 | keys %{ $dispatcher->{_descriptors} }), |
|
|
722 | |
|
|
723 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
|
|
724 | ? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0), |
|
|
725 | 0, sub { }, |
503 | ); |
726 | ); |
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 | }; |
727 | }; |
509 | |
728 | |
510 | The callbacks are irrelevant, the only purpose of those watchers is |
729 | 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 |
730 | 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 |
731 | one of those events occurs (socket readable, or timer timed out). The |
513 | clean up: |
732 | corresponding EV::check watcher will then clean up: |
514 | |
733 | |
515 | our $snmp_check = EV::check sub { |
734 | our $snmp_check = EV::check sub { |
516 | # destroy all watchers |
735 | # destroy all watchers |
517 | @snmp_watcher = (); |
736 | @snmp_watcher = (); |
518 | |
737 | |
519 | # make the dispatcher handle any new stuff |
738 | # make the dispatcher handle any new stuff |
|
|
739 | ... not shown |
520 | }; |
740 | }; |
521 | |
741 | |
522 | The callbacks of the created watchers will not be called as the watchers |
742 | 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 |
743 | are destroyed before this cna happen (remember EV::check gets called |
524 | first). |
744 | first). |
525 | |
745 | |
526 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
746 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
527 | |
747 | |
528 | =back |
748 | =back |
529 | |
749 | |
|
|
750 | |
|
|
751 | =head3 FORK WATCHERS - the audacity to resume the event loop after a fork |
|
|
752 | |
|
|
753 | Fork watchers are called when a C<fork ()> was detected. The invocation |
|
|
754 | is done before the event loop blocks next and before C<check> watchers |
|
|
755 | are being called, and only in the child after the fork. |
|
|
756 | |
|
|
757 | =over 4 |
|
|
758 | |
|
|
759 | =item $w = EV::fork $callback |
|
|
760 | |
|
|
761 | =item $w = EV::fork_ns $callback |
|
|
762 | |
|
|
763 | Call the callback before the event loop is resumed in the child process |
|
|
764 | after a fork. |
|
|
765 | |
|
|
766 | The C<fork_ns> variant doesn't start (activate) the newly created watcher. |
|
|
767 | |
|
|
768 | =back |
|
|
769 | |
|
|
770 | |
|
|
771 | =head1 PERL SIGNALS |
|
|
772 | |
|
|
773 | While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour |
|
|
774 | with EV is as the same as any other C library: Perl-signals will only be |
|
|
775 | handled when Perl runs, which means your signal handler might be invoked |
|
|
776 | only the next time an event callback is invoked. |
|
|
777 | |
|
|
778 | The solution is to use EV signal watchers (see C<EV::signal>), which will |
|
|
779 | ensure proper operations with regards to other event watchers. |
|
|
780 | |
|
|
781 | If you cannot do this for whatever reason, you can also force a watcher |
|
|
782 | to be called on every event loop iteration by installing a C<EV::check> |
|
|
783 | watcher: |
|
|
784 | |
|
|
785 | my $async_check = EV::check sub { }; |
|
|
786 | |
|
|
787 | This ensures that perl shortly gets into control for a short time, and |
|
|
788 | also ensures slower overall operation. |
|
|
789 | |
530 | =head1 THREADS |
790 | =head1 THREADS |
531 | |
791 | |
532 | Threads are not supported by this in any way. Perl pseudo-threads is evil |
792 | Threads are not supported by this module in any way. Perl pseudo-threads |
533 | stuff and must die. |
793 | is evil stuff and must die. As soon as Perl gains real threads I will work |
|
|
794 | on thread support for it. |
|
|
795 | |
|
|
796 | =head1 FORK |
|
|
797 | |
|
|
798 | Most of the "improved" event delivering mechanisms of modern operating |
|
|
799 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
|
|
800 | not supported and usually destructive). Libev makes it possible to work |
|
|
801 | around this by having a function that recreates the kernel state after |
|
|
802 | fork in the child. |
|
|
803 | |
|
|
804 | On non-win32 platforms, this module requires the pthread_atfork |
|
|
805 | functionality to do this automatically for you. This function is quite |
|
|
806 | buggy on most BSDs, though, so YMMV. The overhead for this is quite |
|
|
807 | negligible, because everything the function currently does is set a flag |
|
|
808 | that is checked only when the event loop gets used the next time, so when |
|
|
809 | you do fork but not use EV, the overhead is minimal. |
|
|
810 | |
|
|
811 | On win32, there is no notion of fork so all this doesn't apply, of course. |
534 | |
812 | |
535 | =cut |
813 | =cut |
536 | |
814 | |
537 | our $DIED = sub { |
815 | our $DIED = sub { |
538 | warn "EV: error in callback (ignoring): $@"; |
816 | warn "EV: error in callback (ignoring): $@"; |
… | |
… | |
543 | |
821 | |
544 | 1; |
822 | 1; |
545 | |
823 | |
546 | =head1 SEE ALSO |
824 | =head1 SEE ALSO |
547 | |
825 | |
548 | L<EV::DNS>. |
826 | L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as |
|
|
827 | event loop), L<Coro::EV> (efficient coroutines with EV). |
549 | |
828 | |
550 | =head1 AUTHOR |
829 | =head1 AUTHOR |
551 | |
830 | |
552 | Marc Lehmann <schmorp@schmorp.de> |
831 | Marc Lehmann <schmorp@schmorp.de> |
553 | http://home.schmorp.de/ |
832 | http://home.schmorp.de/ |