… | |
… | |
37 | # CHILD/PID STATUS CHANGES |
37 | # CHILD/PID STATUS CHANGES |
38 | |
38 | |
39 | my $w = EV::child 666, sub { |
39 | my $w = EV::child 666, sub { |
40 | my ($w, $revents) = @_; |
40 | my ($w, $revents) = @_; |
41 | my $status = $w->rstatus; |
41 | my $status = $w->rstatus; |
|
|
42 | }; |
|
|
43 | |
|
|
44 | # STAT CHANGES |
|
|
45 | my $w = EV::stat "/etc/passwd", 10, sub { |
|
|
46 | my ($w, $revents) = @_; |
|
|
47 | warn $w->path, " has changed somehow.\n"; |
42 | }; |
48 | }; |
43 | |
49 | |
44 | # MAINLOOP |
50 | # MAINLOOP |
45 | EV::loop; # loop until EV::unloop is called or all watchers stop |
51 | EV::loop; # loop until EV::unloop is called or all watchers stop |
46 | EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled |
52 | EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled |
… | |
… | |
50 | This module provides an interface to libev |
56 | This module provides an interface to libev |
51 | (<http://software.schmorp.de/pkg/libev.html>). While the documentation |
57 | (<http://software.schmorp.de/pkg/libev.html>). While the documentation |
52 | below is comprehensive, one might also consult the documentation of |
58 | below is comprehensive, one might also consult the documentation of |
53 | libev itself (<http://cvs.schmorp.de/libev/ev.html>) for more subtle |
59 | libev itself (<http://cvs.schmorp.de/libev/ev.html>) for more subtle |
54 | details on watcher semantics or some discussion on the available |
60 | details on watcher semantics or some discussion on the available |
55 | backends, or how to force a specific backend with "LIBEV_FLAGS". |
61 | backends, or how to force a specific backend with "LIBEV_FLAGS", or just |
|
|
62 | about in any case because it has much more detailed information. |
56 | |
63 | |
57 | BASIC INTERFACE |
64 | BASIC INTERFACE |
58 | $EV::DIED |
65 | $EV::DIED |
59 | Must contain a reference to a function that is called when a |
66 | Must contain a reference to a function that is called when a |
60 | callback throws an exception (with $@ containing thr error). The |
67 | callback throws an exception (with $@ containing the error). The |
61 | default prints an informative message and continues. |
68 | default prints an informative message and continues. |
62 | |
69 | |
63 | If this callback throws an exception it will be silently ignored. |
70 | If this callback throws an exception it will be silently ignored. |
64 | |
71 | |
65 | $time = EV::time |
72 | $time = EV::time |
… | |
… | |
88 | When called with no arguments or an argument of EV::UNLOOP_ONE, |
95 | When called with no arguments or an argument of EV::UNLOOP_ONE, |
89 | makes the innermost call to EV::loop return. |
96 | makes the innermost call to EV::loop return. |
90 | |
97 | |
91 | When called with an argument of EV::UNLOOP_ALL, all calls to |
98 | When called with an argument of EV::UNLOOP_ALL, all calls to |
92 | EV::loop will return as fast as possible. |
99 | EV::loop will return as fast as possible. |
|
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100 | |
|
|
101 | $count = EV::loop_count |
|
|
102 | Return the number of times the event loop has polled for new events. |
|
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103 | Sometiems useful as a generation counter. |
93 | |
104 | |
94 | EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
105 | EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
95 | This function rolls together an I/O and a timer watcher for a single |
106 | This function rolls together an I/O and a timer watcher for a single |
96 | one-shot event without the need for managing a watcher object. |
107 | one-shot event without the need for managing a watcher object. |
97 | |
108 | |
… | |
… | |
111 | |
122 | |
112 | EV::once doesn't return anything: the watchers stay active till |
123 | EV::once doesn't return anything: the watchers stay active till |
113 | either of them triggers, then they will be stopped and freed, and |
124 | either of them triggers, then they will be stopped and freed, and |
114 | the callback invoked. |
125 | the callback invoked. |
115 | |
126 | |
116 | WATCHER |
127 | EV::feed_fd_event ($fd, $revents) |
|
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128 | Feed an event on a file descriptor into EV. EV will react to this |
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129 | call as if the readyness notifications specified by $revents (a |
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130 | combination of "EV::READ" and "EV::WRITE") happened on the file |
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131 | descriptor $fd. |
|
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132 | |
|
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133 | EV::feed_signal_event ($signal) |
|
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134 | Feed a signal event into EV. EV will react to this call as if the |
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135 | signal specified by $signal had occured. |
|
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136 | |
|
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137 | WATCHER OBJECTS |
117 | A watcher is an object that gets created to record your interest in some |
138 | A watcher is an object that gets created to record your interest in some |
118 | event. For instance, if you want to wait for STDIN to become readable, |
139 | event. For instance, if you want to wait for STDIN to become readable, |
119 | you would create an EV::io watcher for that: |
140 | you would create an EV::io watcher for that: |
120 | |
141 | |
121 | my $watcher = EV::io *STDIN, EV::READ, sub { |
142 | my $watcher = EV::io *STDIN, EV::READ, sub { |
… | |
… | |
129 | received events. |
150 | received events. |
130 | |
151 | |
131 | Each watcher type has its associated bit in revents, so you can use the |
152 | Each watcher type has its associated bit in revents, so you can use the |
132 | same callback for multiple watchers. The event mask is named after the |
153 | same callback for multiple watchers. The event mask is named after the |
133 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
154 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
134 | EV::periodic sets EV::PERIODIC and so on, with the exception of IO |
155 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O |
135 | events (which can set both EV::READ and EV::WRITE bits), and EV::timer |
156 | events (which can set both EV::READ and EV::WRITE bits), and EV::timer |
136 | (which uses EV::TIMEOUT). |
157 | (which uses EV::TIMEOUT). |
137 | |
158 | |
138 | In the rare case where one wants to create a watcher but not start it at |
159 | In the rare case where one wants to create a watcher but not start it at |
139 | the same time, each constructor has a variant with a trailing "_ns" in |
160 | the same time, each constructor has a variant with a trailing "_ns" in |
… | |
… | |
145 | |
166 | |
146 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
167 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
147 | ->fh and so on) automatically stop and start it again if it is active, |
168 | ->fh and so on) automatically stop and start it again if it is active, |
148 | which means pending events get lost. |
169 | which means pending events get lost. |
149 | |
170 | |
150 | WATCHER TYPES |
171 | COMMON WATCHER METHODS |
151 | Now lets move to the existing watcher types and asociated methods. |
172 | This section lists methods common to all watchers. |
152 | |
|
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153 | The following methods are available for all watchers. Then followes a |
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154 | description of each watcher constructor (EV::io, EV::timer, |
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155 | EV::periodic, EV::signal, EV::child, EV::idle, EV::prepare and |
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156 | EV::check), followed by any type-specific methods (if any). |
|
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157 | |
173 | |
158 | $w->start |
174 | $w->start |
159 | Starts a watcher if it isn't active already. Does nothing to an |
175 | Starts a watcher if it isn't active already. Does nothing to an |
160 | already active watcher. By default, all watchers start out in the |
176 | already active watcher. By default, all watchers start out in the |
161 | active state (see the description of the "_ns" variants if you need |
177 | active state (see the description of the "_ns" variants if you need |
162 | stopped watchers). |
178 | stopped watchers). |
163 | |
179 | |
164 | $w->stop |
180 | $w->stop |
165 | Stop a watcher if it is active. Also clear any pending events |
181 | Stop a watcher if it is active. Also clear any pending events |
166 | (events that have been received but that didn't yet result in a |
182 | (events that have been received but that didn't yet result in a |
167 | callback invocation), regardless of wether the watcher was active or |
183 | callback invocation), regardless of whether the watcher was active |
168 | not. |
184 | or not. |
169 | |
185 | |
170 | $bool = $w->is_active |
186 | $bool = $w->is_active |
171 | Returns true if the watcher is active, false otherwise. |
187 | Returns true if the watcher is active, false otherwise. |
172 | |
188 | |
173 | $current_data = $w->data |
189 | $current_data = $w->data |
… | |
… | |
196 | The default priority of any newly-created watcher is 0. |
212 | The default priority of any newly-created watcher is 0. |
197 | |
213 | |
198 | Note that the priority semantics have not yet been fleshed out and |
214 | Note that the priority semantics have not yet been fleshed out and |
199 | are subject to almost certain change. |
215 | are subject to almost certain change. |
200 | |
216 | |
201 | $w->trigger ($revents) |
217 | $w->invoke ($revents) |
202 | Call the callback *now* with the given event mask. |
218 | Call the callback *now* with the given event mask. |
|
|
219 | |
|
|
220 | $w->feed_event ($revents) |
|
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221 | Feed some events on this watcher into EV. EV will react to this call |
|
|
222 | as if the watcher had received the given $revents mask. |
|
|
223 | |
|
|
224 | $revents = $w->clear_pending |
|
|
225 | If the watcher is pending, this function returns clears its pending |
|
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226 | status and returns its $revents bitset (as if its callback was |
|
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227 | invoked). If the watcher isn't pending it does nothing and returns |
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228 | 0. |
203 | |
229 | |
204 | $previous_state = $w->keepalive ($bool) |
230 | $previous_state = $w->keepalive ($bool) |
205 | Normally, "EV::loop" will return when there are no active watchers |
231 | Normally, "EV::loop" will return when there are no active watchers |
206 | (which is a "deadlock" because no progress can be made anymore). |
232 | (which is a "deadlock" because no progress can be made anymore). |
207 | This is convinient because it allows you to start your watchers (and |
233 | This is convinient because it allows you to start your watchers (and |
… | |
… | |
222 | returning. |
248 | returning. |
223 | |
249 | |
224 | The initial value for keepalive is true (enabled), and you cna |
250 | The initial value for keepalive is true (enabled), and you cna |
225 | change it any time. |
251 | change it any time. |
226 | |
252 | |
227 | Example: Register an IO watcher for some UDP socket but do not keep |
253 | Example: Register an I/O watcher for some UDP socket but do not keep |
228 | the event loop from running just because of that watcher. |
254 | the event loop from running just because of that watcher. |
229 | |
255 | |
230 | my $udp_socket = ... |
256 | my $udp_socket = ... |
231 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
257 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
232 | $udp_watcher->keepalive (0); |
258 | $udp_watcher->keepalive (0); |
233 | |
259 | |
|
|
260 | WATCHER TYPES |
|
|
261 | Each of the following subsections describes a single watcher type. |
|
|
262 | |
|
|
263 | I/O WATCHERS - is this file descriptor readable or writable? |
234 | $w = EV::io $fileno_or_fh, $eventmask, $callback |
264 | $w = EV::io $fileno_or_fh, $eventmask, $callback |
235 | $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
265 | $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
236 | As long as the returned watcher object is alive, call the $callback |
266 | As long as the returned watcher object is alive, call the $callback |
237 | when the events specified in $eventmask. |
267 | when at least one of events specified in $eventmask occurs. |
238 | |
268 | |
239 | The $eventmask can be one or more of these constants ORed together: |
269 | The $eventmask can be one or more of these constants ORed together: |
240 | |
270 | |
241 | EV::READ wait until read() wouldn't block anymore |
271 | EV::READ wait until read() wouldn't block anymore |
242 | EV::WRITE wait until write() wouldn't block anymore |
272 | EV::WRITE wait until write() wouldn't block anymore |
… | |
… | |
254 | |
284 | |
255 | $current_eventmask = $w->events |
285 | $current_eventmask = $w->events |
256 | $old_eventmask = $w->events ($new_eventmask) |
286 | $old_eventmask = $w->events ($new_eventmask) |
257 | Returns the previously set event mask and optionally set a new one. |
287 | Returns the previously set event mask and optionally set a new one. |
258 | |
288 | |
|
|
289 | TIMER WATCHERS - relative and optionally repeating timeouts |
259 | $w = EV::timer $after, $repeat, $callback |
290 | $w = EV::timer $after, $repeat, $callback |
260 | $w = EV::timer_ns $after, $repeat, $callback |
291 | $w = EV::timer_ns $after, $repeat, $callback |
261 | Calls the callback after $after seconds (which may be fractional). |
292 | Calls the callback after $after seconds (which may be fractional). |
262 | If $repeat is non-zero, the timer will be restarted (with the |
293 | If $repeat is non-zero, the timer will be restarted (with the |
263 | $repeat value as $after) after the callback returns. |
294 | $repeat value as $after) after the callback returns. |
… | |
… | |
277 | The "timer_ns" variant doesn't start (activate) the newly created |
308 | The "timer_ns" variant doesn't start (activate) the newly created |
278 | watcher. |
309 | watcher. |
279 | |
310 | |
280 | $w->set ($after, $repeat) |
311 | $w->set ($after, $repeat) |
281 | Reconfigures the watcher, see the constructor above for details. Can |
312 | Reconfigures the watcher, see the constructor above for details. Can |
282 | be at any time. |
313 | be called at any time. |
283 | |
314 | |
284 | $w->again |
315 | $w->again |
285 | Similar to the "start" method, but has special semantics for |
316 | Similar to the "start" method, but has special semantics for |
286 | repeating timers: |
317 | repeating timers: |
287 | |
318 | |
… | |
… | |
298 | This behaviour is useful when you have a timeout for some IO |
329 | This behaviour is useful when you have a timeout for some IO |
299 | operation. You create a timer object with the same value for $after |
330 | operation. You create a timer object with the same value for $after |
300 | and $repeat, and then, in the read/write watcher, run the "again" |
331 | and $repeat, and then, in the read/write watcher, run the "again" |
301 | method on the timeout. |
332 | method on the timeout. |
302 | |
333 | |
|
|
334 | PERIODIC WATCHERS - to cron or not to cron? |
303 | $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
335 | $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
304 | $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
336 | $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
305 | Similar to EV::timer, but is not based on relative timeouts but on |
337 | Similar to EV::timer, but is not based on relative timeouts but on |
306 | absolute times. Apart from creating "simple" timers that trigger |
338 | absolute times. Apart from creating "simple" timers that trigger |
307 | "at" the specified time, it can also be used for non-drifting |
339 | "at" the specified time, it can also be used for non-drifting |
… | |
… | |
372 | The "periodic_ns" variant doesn't start (activate) the newly created |
404 | The "periodic_ns" variant doesn't start (activate) the newly created |
373 | watcher. |
405 | watcher. |
374 | |
406 | |
375 | $w->set ($at, $interval, $reschedule_cb) |
407 | $w->set ($at, $interval, $reschedule_cb) |
376 | Reconfigures the watcher, see the constructor above for details. Can |
408 | Reconfigures the watcher, see the constructor above for details. Can |
377 | be at any time. |
409 | be called at any time. |
378 | |
410 | |
379 | $w->again |
411 | $w->again |
380 | Simply stops and starts the watcher again. |
412 | Simply stops and starts the watcher again. |
381 | |
413 | |
|
|
414 | SIGNAL WATCHERS - signal me when a signal gets signalled! |
382 | $w = EV::signal $signal, $callback |
415 | $w = EV::signal $signal, $callback |
383 | $w = EV::signal_ns $signal, $callback |
416 | $w = EV::signal_ns $signal, $callback |
384 | Call the callback when $signal is received (the signal can be |
417 | Call the callback when $signal is received (the signal can be |
385 | specified by number or by name, just as with kill or %SIG). |
418 | specified by number or by name, just as with "kill" or %SIG). |
386 | |
419 | |
387 | EV will grab the signal for the process (the kernel only allows one |
420 | EV will grab the signal for the process (the kernel only allows one |
388 | component to receive a signal at a time) when you start a signal |
421 | component to receive a signal at a time) when you start a signal |
389 | watcher, and removes it again when you stop it. Perl does the same |
422 | watcher, and removes it again when you stop it. Perl does the same |
390 | when you add/remove callbacks to %SIG, so watch out. |
423 | when you add/remove callbacks to %SIG, so watch out. |
… | |
… | |
394 | The "signal_ns" variant doesn't start (activate) the newly created |
427 | The "signal_ns" variant doesn't start (activate) the newly created |
395 | watcher. |
428 | watcher. |
396 | |
429 | |
397 | $w->set ($signal) |
430 | $w->set ($signal) |
398 | Reconfigures the watcher, see the constructor above for details. Can |
431 | Reconfigures the watcher, see the constructor above for details. Can |
399 | be at any time. |
432 | be called at any time. |
400 | |
433 | |
401 | $current_signum = $w->signal |
434 | $current_signum = $w->signal |
402 | $old_signum = $w->signal ($new_signal) |
435 | $old_signum = $w->signal ($new_signal) |
403 | Returns the previously set signal (always as a number not name) and |
436 | Returns the previously set signal (always as a number not name) and |
404 | optionally set a new one. |
437 | optionally set a new one. |
405 | |
438 | |
|
|
439 | CHILD WATCHERS - watch out for process status changes |
406 | $w = EV::child $pid, $callback |
440 | $w = EV::child $pid, $callback |
407 | $w = EV::child_ns $pid, $callback |
441 | $w = EV::child_ns $pid, $callback |
408 | Call the callback when a status change for pid $pid (or any pid if |
442 | Call the callback when a status change for pid $pid (or any pid if |
409 | $pid is 0) has been received. More precisely: when the process |
443 | $pid is 0) has been received. More precisely: when the process |
410 | receives a SIGCHLD, EV will fetch the outstanding exit/wait status |
444 | receives a "SIGCHLD", EV will fetch the outstanding exit/wait status |
411 | for all changed/zombie children and call the callback. |
445 | for all changed/zombie children and call the callback. |
412 | |
446 | |
413 | You can access both status and pid by using the "rstatus" and "rpid" |
447 | It is valid (and fully supported) to install a child watcher after a |
|
|
448 | child has exited but before the event loop has started its next |
|
|
449 | iteration (for example, first you "fork", then the new child process |
|
|
450 | might exit, and only then do you install a child watcher in the |
|
|
451 | parent for the new pid). |
|
|
452 | |
|
|
453 | You can access both exit (or tracing) status and pid by using the |
414 | methods on the watcher object. |
454 | "rstatus" and "rpid" methods on the watcher object. |
415 | |
455 | |
416 | You can have as many pid watchers per pid as you want. |
456 | You can have as many pid watchers per pid as you want, they will all |
|
|
457 | be called. |
417 | |
458 | |
418 | The "child_ns" variant doesn't start (activate) the newly created |
459 | The "child_ns" variant doesn't start (activate) the newly created |
419 | watcher. |
460 | watcher. |
420 | |
461 | |
421 | $w->set ($pid) |
462 | $w->set ($pid) |
422 | Reconfigures the watcher, see the constructor above for details. Can |
463 | Reconfigures the watcher, see the constructor above for details. Can |
423 | be at any time. |
464 | be called at any time. |
424 | |
465 | |
425 | $current_pid = $w->pid |
466 | $current_pid = $w->pid |
426 | $old_pid = $w->pid ($new_pid) |
467 | $old_pid = $w->pid ($new_pid) |
427 | Returns the previously set process id and optionally set a new one. |
468 | Returns the previously set process id and optionally set a new one. |
428 | |
469 | |
… | |
… | |
432 | |
473 | |
433 | $pid = $w->rpid |
474 | $pid = $w->rpid |
434 | Return the pid of the awaited child (useful when you have installed |
475 | Return the pid of the awaited child (useful when you have installed |
435 | a watcher for all pids). |
476 | a watcher for all pids). |
436 | |
477 | |
|
|
478 | STAT WATCHERS - did the file attributes just change? |
|
|
479 | $w = EV::stat $path, $interval, $callback |
|
|
480 | $w = EV::stat_ns $path, $interval, $callback |
|
|
481 | Call the callback when a file status change has been detected on |
|
|
482 | $path. The $path does not need to exist, changing from "path exists" |
|
|
483 | to "path does not exist" is a status change like any other. |
|
|
484 | |
|
|
485 | The $interval is a recommended polling interval for systems where |
|
|
486 | OS-supported change notifications don't exist or are not supported. |
|
|
487 | If you use 0 then an unspecified default is used (which is highly |
|
|
488 | recommended!), which is to be expected to be around five seconds |
|
|
489 | usually. |
|
|
490 | |
|
|
491 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
492 | as even with OS-supported change notifications, this can be |
|
|
493 | resource-intensive. |
|
|
494 | |
|
|
495 | The "stat_ns" variant doesn't start (activate) the newly created |
|
|
496 | watcher. |
|
|
497 | |
|
|
498 | ... = $w->stat |
|
|
499 | This call is very similar to the perl "stat" built-in: It stats |
|
|
500 | (using "lstat") the path specified in the watcher and sets perls |
|
|
501 | stat cache (as well as EV's idea of the current stat values) to the |
|
|
502 | values found. |
|
|
503 | |
|
|
504 | In scalar context, a boolean is return indicating success or failure |
|
|
505 | of the stat. In list context, the same 13-value list as with stat is |
|
|
506 | returned (except that the blksize and blocks fields are not |
|
|
507 | reliable). |
|
|
508 | |
|
|
509 | In the case of an error, errno is set to "ENOENT" (regardless of the |
|
|
510 | actual error value) and the "nlink" value is forced to zero (if the |
|
|
511 | stat was successful then nlink is guaranteed to be non-zero). |
|
|
512 | |
|
|
513 | See also the next two entries for more info. |
|
|
514 | |
|
|
515 | ... = $w->attr |
|
|
516 | Just like "$w->stat", but without the initial stat'ing: this returns |
|
|
517 | the values most recently detected by EV. See the next entry for more |
|
|
518 | info. |
|
|
519 | |
|
|
520 | ... = $w->prev |
|
|
521 | Just like "$w->stat", but without the initial stat'ing: this returns |
|
|
522 | the previous set of values, before the change. |
|
|
523 | |
|
|
524 | That is, when the watcher callback is invoked, "$w->prev" will be |
|
|
525 | set to the values found *before* a change was detected, while |
|
|
526 | "$w->attr" returns the values found leading to the change detection. |
|
|
527 | The difference (if any) between "prev" and "attr" is what triggered |
|
|
528 | the callback. |
|
|
529 | |
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530 | If you did something to the filesystem object and do not want to |
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531 | trigger yet another change, you can call "stat" to update EV's idea |
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532 | of what the current attributes are. |
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533 | |
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534 | $w->set ($path, $interval) |
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535 | Reconfigures the watcher, see the constructor above for details. Can |
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536 | be called at any time. |
|
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537 | |
|
|
538 | $current_path = $w->path |
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539 | $old_path = $w->path ($new_path) |
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540 | Returns the previously set path and optionally set a new one. |
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541 | |
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542 | $current_interval = $w->interval |
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543 | $old_interval = $w->interval ($new_interval) |
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544 | Returns the previously set interval and optionally set a new one. |
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545 | Can be used to query the actual interval used. |
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546 | |
|
|
547 | IDLE WATCHERS - when you've got nothing better to do... |
437 | $w = EV::idle $callback |
548 | $w = EV::idle $callback |
438 | $w = EV::idle_ns $callback |
549 | $w = EV::idle_ns $callback |
439 | Call the callback when there are no pending io, timer/periodic, |
550 | Call the callback when there are no other pending watchers of the |
440 | signal or child events, i.e. when the process is idle. |
551 | same or higher priority (excluding check, prepare and other idle |
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552 | watchers of the same or lower priority, of course). They are called |
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553 | idle watchers because when the watcher is the highest priority |
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554 | pending event in the process, the process is considered to be idle |
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555 | at that priority. |
|
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556 | |
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557 | If you want a watcher that is only ever called when *no* other |
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558 | events are outstanding you have to set the priority to "EV::MINPRI". |
441 | |
559 | |
442 | The process will not block as long as any idle watchers are active, |
560 | The process will not block as long as any idle watchers are active, |
443 | and they will be called repeatedly until stopped. |
561 | and they will be called repeatedly until stopped. |
444 | |
562 | |
|
|
563 | For example, if you have idle watchers at priority 0 and 1, and an |
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564 | I/O watcher at priority 0, then the idle watcher at priority 1 and |
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565 | the I/O watcher will always run when ready. Only when the idle |
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566 | watcher at priority 1 is stopped and the I/O watcher at priority 0 |
|
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567 | is not pending with the 0-priority idle watcher be invoked. |
|
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568 | |
445 | The "idle_ns" variant doesn't start (activate) the newly created |
569 | The "idle_ns" variant doesn't start (activate) the newly created |
446 | watcher. |
570 | watcher. |
447 | |
571 | |
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572 | PREPARE WATCHERS - customise your event loop! |
448 | $w = EV::prepare $callback |
573 | $w = EV::prepare $callback |
449 | $w = EV::prepare_ns $callback |
574 | $w = EV::prepare_ns $callback |
450 | Call the callback just before the process would block. You can still |
575 | Call the callback just before the process would block. You can still |
451 | create/modify any watchers at this point. |
576 | create/modify any watchers at this point. |
452 | |
577 | |
453 | See the EV::check watcher, below, for explanations and an example. |
578 | See the EV::check watcher, below, for explanations and an example. |
454 | |
579 | |
455 | The "prepare_ns" variant doesn't start (activate) the newly created |
580 | The "prepare_ns" variant doesn't start (activate) the newly created |
456 | watcher. |
581 | watcher. |
457 | |
582 | |
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583 | CHECK WATCHERS - customise your event loop even more! |
458 | $w = EV::check $callback |
584 | $w = EV::check $callback |
459 | $w = EV::check_ns $callback |
585 | $w = EV::check_ns $callback |
460 | Call the callback just after the process wakes up again (after it |
586 | Call the callback just after the process wakes up again (after it |
461 | has gathered events), but before any other callbacks have been |
587 | has gathered events), but before any other callbacks have been |
462 | invoked. |
588 | invoked. |
… | |
… | |
475 | or return; |
601 | or return; |
476 | |
602 | |
477 | # make the dispatcher handle any outstanding stuff |
603 | # make the dispatcher handle any outstanding stuff |
478 | ... not shown |
604 | ... not shown |
479 | |
605 | |
480 | # create an IO watcher for each and every socket |
606 | # create an I/O watcher for each and every socket |
481 | @snmp_watcher = ( |
607 | @snmp_watcher = ( |
482 | (map { EV::io $_, EV::READ, sub { } } |
608 | (map { EV::io $_, EV::READ, sub { } } |
483 | keys %{ $dispatcher->{_descriptors} }), |
609 | keys %{ $dispatcher->{_descriptors} }), |
484 | |
610 | |
485 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
611 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
… | |
… | |
505 | watchers are destroyed before this cna happen (remember EV::check |
631 | watchers are destroyed before this cna happen (remember EV::check |
506 | gets called first). |
632 | gets called first). |
507 | |
633 | |
508 | The "check_ns" variant doesn't start (activate) the newly created |
634 | The "check_ns" variant doesn't start (activate) the newly created |
509 | watcher. |
635 | watcher. |
|
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636 | |
|
|
637 | FORK WATCHERS - the audacity to resume the event loop after a fork |
|
|
638 | Fork watchers are called when a "fork ()" was detected. The invocation |
|
|
639 | is done before the event loop blocks next and before "check" watchers |
|
|
640 | are being called, and only in the child after the fork. |
|
|
641 | |
|
|
642 | $w = EV::fork $callback |
|
|
643 | $w = EV::fork_ns $callback |
|
|
644 | Call the callback before the event loop is resumed in the child |
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645 | process after a fork. |
|
|
646 | |
|
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647 | The "fork_ns" variant doesn't start (activate) the newly created |
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648 | watcher. |
|
|
649 | |
|
|
650 | PERL SIGNALS |
|
|
651 | While Perl signal handling (%SIG) is not affected by EV, the behaviour |
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|
652 | with EV is as the same as any other C library: Perl-signals will only be |
|
|
653 | handled when Perl runs, which means your signal handler might be invoked |
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654 | only the next time an event callback is invoked. |
|
|
655 | |
|
|
656 | The solution is to use EV signal watchers (see "EV::signal"), which will |
|
|
657 | ensure proper operations with regards to other event watchers. |
|
|
658 | |
|
|
659 | If you cannot do this for whatever reason, you can also force a watcher |
|
|
660 | to be called on every event loop iteration by installing a "EV::check" |
|
|
661 | watcher: |
|
|
662 | |
|
|
663 | my $async_check = EV::check sub { }; |
|
|
664 | |
|
|
665 | This ensures that perl shortly gets into control for a short time, and |
|
|
666 | also ensures slower overall operation. |
510 | |
667 | |
511 | THREADS |
668 | THREADS |
512 | Threads are not supported by this module in any way. Perl pseudo-threads |
669 | Threads are not supported by this module in any way. Perl pseudo-threads |
513 | is evil stuff and must die. As soon as Perl gains real threads I will |
670 | is evil stuff and must die. As soon as Perl gains real threads I will |
514 | work on thread support for it. |
671 | work on thread support for it. |
… | |
… | |
529 | |
686 | |
530 | On win32, there is no notion of fork so all this doesn't apply, of |
687 | On win32, there is no notion of fork so all this doesn't apply, of |
531 | course. |
688 | course. |
532 | |
689 | |
533 | SEE ALSO |
690 | SEE ALSO |
534 | L<EV::DNS>. |
691 | EV::ADNS (asynchronous dns), Glib::EV (makes Glib/Gtk2 use EV as event |
|
|
692 | loop), Coro::EV (efficient coroutines with EV). |
535 | |
693 | |
536 | AUTHOR |
694 | AUTHOR |
537 | Marc Lehmann <schmorp@schmorp.de> |
695 | Marc Lehmann <schmorp@schmorp.de> |
538 | http://home.schmorp.de/ |
696 | http://home.schmorp.de/ |
539 | |
697 | |