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2 | EV - perl interface to libev, a high performance full-featured event |
2 | EV - perl interface to libev, a high performance full-featured event |
3 | loop |
3 | loop |
4 | |
4 | |
5 | SYNOPSIS |
5 | SYNOPSIS |
6 | use EV; |
6 | use EV; |
7 | |
7 | |
8 | # TIMERS |
8 | # TIMERS |
9 | |
9 | |
10 | my $w = EV::timer 2, 0, sub { |
10 | my $w = EV::timer 2, 0, sub { |
11 | warn "is called after 2s"; |
11 | warn "is called after 2s"; |
12 | }; |
12 | }; |
13 | |
13 | |
14 | my $w = EV::timer 2, 2, sub { |
14 | my $w = EV::timer 2, 2, sub { |
15 | warn "is called roughly every 2s (repeat = 2)"; |
15 | warn "is called roughly every 2s (repeat = 2)"; |
16 | }; |
16 | }; |
17 | |
17 | |
18 | undef $w; # destroy event watcher again |
18 | undef $w; # destroy event watcher again |
19 | |
19 | |
20 | my $w = EV::periodic 0, 60, 0, sub { |
20 | my $w = EV::periodic 0, 60, 0, sub { |
21 | warn "is called every minute, on the minute, exactly"; |
21 | warn "is called every minute, on the minute, exactly"; |
22 | }; |
22 | }; |
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23 | |
23 | |
24 | # IO |
24 | # IO |
25 | |
25 | |
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26 | my $w = EV::io *STDIN, EV::READ, sub { |
26 | my $w = EV::io *STDIN, EV::READ, sub { |
27 | my ($w, $revents) = @_; # all callbacks receive the watcher and event mask |
27 | my ($w, $revents) = @_; # all callbacks receive the watcher and event mask |
28 | warn "stdin is readable, you entered: ", <STDIN>; |
28 | warn "stdin is readable, you entered: ", <STDIN>; |
29 | }; |
29 | }; |
30 | |
30 | |
31 | # SIGNALS |
31 | # SIGNALS |
32 | |
32 | |
33 | my $w = EV::signal 'QUIT', sub { |
33 | my $w = EV::signal 'QUIT', sub { |
34 | warn "sigquit received\n"; |
34 | warn "sigquit received\n"; |
35 | }; |
35 | }; |
36 | |
36 | |
37 | # CHILD/PID STATUS CHANGES |
37 | # CHILD/PID STATUS CHANGES |
38 | |
38 | |
39 | my $w = EV::child 666, 0, sub { |
39 | my $w = EV::child 666, 0, sub { |
40 | my ($w, $revents) = @_; |
40 | my ($w, $revents) = @_; |
41 | my $status = $w->rstatus; |
41 | my $status = $w->rstatus; |
42 | }; |
42 | }; |
43 | |
43 | |
44 | # STAT CHANGES |
44 | # STAT CHANGES |
45 | my $w = EV::stat "/etc/passwd", 10, sub { |
45 | my $w = EV::stat "/etc/passwd", 10, sub { |
46 | my ($w, $revents) = @_; |
46 | my ($w, $revents) = @_; |
47 | warn $w->path, " has changed somehow.\n"; |
47 | warn $w->path, " has changed somehow.\n"; |
48 | }; |
48 | }; |
49 | |
49 | |
50 | # MAINLOOP |
50 | # MAINLOOP |
51 | 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 |
52 | 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 |
53 | EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block |
53 | EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block |
54 | |
54 | |
55 | DESCRIPTION |
55 | DESCRIPTION |
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84 | default loop as this is fastest (perl-wise), best supported by other |
84 | default loop as this is fastest (perl-wise), best supported by other |
85 | modules (e.g. AnyEvent or Coro) and most portable event loop. |
85 | modules (e.g. AnyEvent or Coro) and most portable event loop. |
86 | |
86 | |
87 | For specific programs you can create additional event loops dynamically. |
87 | For specific programs you can create additional event loops dynamically. |
88 | |
88 | |
89 | If you want to take avdantage of kqueue (which often works properly for |
89 | If you want to take advantage of kqueue (which often works properly for |
90 | sockets only) even though the default loop doesn't enable it, you can |
90 | sockets only) even though the default loop doesn't enable it, you can |
91 | *embed* a kqueue loop into the default loop: running the default loop |
91 | *embed* a kqueue loop into the default loop: running the default loop |
92 | will then also service the kqueue loop to some extent. See the example |
92 | will then also service the kqueue loop to some extent. See the example |
93 | in the section about embed watchers for an example on how to achieve |
93 | in the section about embed watchers for an example on how to achieve |
94 | that. |
94 | that. |
95 | |
95 | |
96 | $loop = new EV::loop [$flags] |
96 | $loop = new EV::Loop [$flags] |
97 | Create a new event loop as per the specified flags. Please refer to |
97 | Create a new event loop as per the specified flags. Please refer to |
98 | the "ev_loop_new ()" function description in the libev documentation |
98 | the "ev_loop_new ()" function description in the libev documentation |
99 | (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI |
99 | (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI |
100 | ONS>, or locally-installed as EV::libev manpage) for more info. |
100 | ONS>, or locally-installed as EV::libev manpage) for more info. |
101 | |
101 | |
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149 | Returns the current time in (fractional) seconds since the epoch. |
149 | Returns the current time in (fractional) seconds since the epoch. |
150 | |
150 | |
151 | $time = EV::now |
151 | $time = EV::now |
152 | $time = $loop->now |
152 | $time = $loop->now |
153 | Returns the time the last event loop iteration has been started. |
153 | Returns the time the last event loop iteration has been started. |
154 | This is the time that (relative) timers are based on, and refering |
154 | This is the time that (relative) timers are based on, and referring |
155 | to it is usually faster then calling EV::time. |
155 | to it is usually faster then calling EV::time. |
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156 | |
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157 | EV::now_update |
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158 | $loop->now_update |
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159 | Establishes the current time by querying the kernel, updating the |
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160 | time returned by "EV::now" in the progress. This is a costly |
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161 | operation and is usually done automatically within "EV::loop". |
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162 | |
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163 | This function is rarely useful, but when some event callback runs |
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164 | for a very long time without entering the event loop, updating |
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165 | libev's idea of the current time is a good idea. |
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166 | |
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167 | EV::suspend |
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168 | $loop->suspend |
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169 | EV::resume |
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170 | $loop->resume |
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171 | These two functions suspend and resume a loop, for use when the loop |
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172 | is not used for a while and timeouts should not be processed. |
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173 | |
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174 | A typical use case would be an interactive program such as a game: |
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175 | When the user presses "^Z" to suspend the game and resumes it an |
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176 | hour later it would be best to handle timeouts as if no time had |
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177 | actually passed while the program was suspended. This can be |
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178 | achieved by calling "suspend" in your "SIGTSTP" handler, sending |
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179 | yourself a "SIGSTOP" and calling "resume" directly afterwards to |
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180 | resume timer processing. |
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181 | |
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182 | Effectively, all "timer" watchers will be delayed by the time spend |
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183 | between "suspend" and "resume", and all "periodic" watchers will be |
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184 | rescheduled (that is, they will lose any events that would have |
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185 | occured while suspended). |
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186 | |
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187 | After calling "suspend" you must not call *any* function on the |
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188 | given loop other than "resume", and you must not call "resume" |
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189 | without a previous call to "suspend". |
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190 | |
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191 | Calling "suspend"/"resume" has the side effect of updating the event |
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192 | loop time (see "now_update"). |
156 | |
193 | |
157 | $backend = EV::backend |
194 | $backend = EV::backend |
158 | $backend = $loop->backend |
195 | $backend = $loop->backend |
159 | Returns an integer describing the backend used by libev |
196 | Returns an integer describing the backend used by libev |
160 | (EV::METHOD_SELECT or EV::METHOD_EPOLL). |
197 | (EV::BACKEND_SELECT or EV::BACKEND_EPOLL). |
161 | |
198 | |
162 | EV::loop [$flags] |
199 | EV::loop [$flags] |
163 | $loop->loop ([$flags]) |
200 | $loop->loop ([$flags]) |
164 | Begin checking for events and calling callbacks. It returns when a |
201 | Begin checking for events and calling callbacks. It returns when a |
165 | callback calls EV::unloop. |
202 | callback calls EV::unloop. |
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179 | EV::loop will return as fast as possible. |
216 | EV::loop will return as fast as possible. |
180 | |
217 | |
181 | $count = EV::loop_count |
218 | $count = EV::loop_count |
182 | $count = $loop->loop_count |
219 | $count = $loop->loop_count |
183 | Return the number of times the event loop has polled for new events. |
220 | Return the number of times the event loop has polled for new events. |
184 | Sometiems useful as a generation counter. |
221 | Sometimes useful as a generation counter. |
185 | |
222 | |
186 | EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
223 | EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
187 | $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) |
224 | $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) |
188 | This function rolls together an I/O and a timer watcher for a single |
225 | This function rolls together an I/O and a timer watcher for a single |
189 | one-shot event without the need for managing a watcher object. |
226 | one-shot event without the need for managing a watcher object. |
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226 | the libev documentation at |
263 | the libev documentation at |
227 | <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT |
264 | <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT |
228 | ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more |
265 | ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more |
229 | detailed discussion. |
266 | detailed discussion. |
230 | |
267 | |
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268 | $count = EV::pending_count |
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269 | $count = $loop->pending_count |
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270 | Returns the number of currently pending watchers. |
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271 | |
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272 | EV::invoke_pending |
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273 | $loop->invoke_pending |
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274 | Invoke all currently pending watchers. |
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275 | |
231 | WATCHER OBJECTS |
276 | WATCHER OBJECTS |
232 | A watcher is an object that gets created to record your interest in some |
277 | A watcher is an object that gets created to record your interest in some |
233 | event. For instance, if you want to wait for STDIN to become readable, |
278 | event. For instance, if you want to wait for STDIN to become readable, |
234 | you would create an EV::io watcher for that: |
279 | you would create an EV::io watcher for that: |
235 | |
280 | |
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243 | will be called with at least two arguments: the watcher and a bitmask of |
288 | will be called with at least two arguments: the watcher and a bitmask of |
244 | received events. |
289 | received events. |
245 | |
290 | |
246 | Each watcher type has its associated bit in revents, so you can use the |
291 | Each watcher type has its associated bit in revents, so you can use the |
247 | same callback for multiple watchers. The event mask is named after the |
292 | same callback for multiple watchers. The event mask is named after the |
248 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
293 | type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
249 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O |
294 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O |
250 | events (which can set both EV::READ and EV::WRITE bits), and EV::timer |
295 | events (which can set both EV::READ and EV::WRITE bits), and EV::timer |
251 | (which uses EV::TIMEOUT). |
296 | (which uses EV::TIMEOUT). |
252 | |
297 | |
253 | In the rare case where one wants to create a watcher but not start it at |
298 | In the rare case where one wants to create a watcher but not start it at |
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321 | the watcher isn't pending it does nothing and returns 0. |
366 | the watcher isn't pending it does nothing and returns 0. |
322 | |
367 | |
323 | $previous_state = $w->keepalive ($bool) |
368 | $previous_state = $w->keepalive ($bool) |
324 | Normally, "EV::loop" will return when there are no active watchers |
369 | Normally, "EV::loop" will return when there are no active watchers |
325 | (which is a "deadlock" because no progress can be made anymore). |
370 | (which is a "deadlock" because no progress can be made anymore). |
326 | This is convinient because it allows you to start your watchers (and |
371 | This is convenient because it allows you to start your watchers (and |
327 | your jobs), call "EV::loop" once and when it returns you know that |
372 | your jobs), call "EV::loop" once and when it returns you know that |
328 | all your jobs are finished (or they forgot to register some watchers |
373 | all your jobs are finished (or they forgot to register some watchers |
329 | for their task :). |
374 | for their task :). |
330 | |
375 | |
331 | Sometimes, however, this gets in your way, for example when the |
376 | Sometimes, however, this gets in your way, for example when the |
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338 | |
383 | |
339 | In this case you can clear the keepalive status, which means that |
384 | In this case you can clear the keepalive status, which means that |
340 | even though your watcher is active, it won't keep "EV::loop" from |
385 | even though your watcher is active, it won't keep "EV::loop" from |
341 | returning. |
386 | returning. |
342 | |
387 | |
343 | The initial value for keepalive is true (enabled), and you cna |
388 | The initial value for keepalive is true (enabled), and you can |
344 | change it any time. |
389 | change it any time. |
345 | |
390 | |
346 | Example: Register an I/O watcher for some UDP socket but do not keep |
391 | Example: Register an I/O watcher for some UDP socket but do not keep |
347 | the event loop from running just because of that watcher. |
392 | the event loop from running just because of that watcher. |
348 | |
393 | |
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522 | Return the time that the watcher is expected to trigger next. |
567 | Return the time that the watcher is expected to trigger next. |
523 | |
568 | |
524 | SIGNAL WATCHERS - signal me when a signal gets signalled! |
569 | SIGNAL WATCHERS - signal me when a signal gets signalled! |
525 | $w = EV::signal $signal, $callback |
570 | $w = EV::signal $signal, $callback |
526 | $w = EV::signal_ns $signal, $callback |
571 | $w = EV::signal_ns $signal, $callback |
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572 | $w = $loop->signal ($signal, $callback) |
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573 | $w = $loop->signal_ns ($signal, $callback) |
527 | Call the callback when $signal is received (the signal can be |
574 | Call the callback when $signal is received (the signal can be |
528 | specified by number or by name, just as with "kill" or %SIG). |
575 | specified by number or by name, just as with "kill" or %SIG). |
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576 | |
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577 | Only one event loop can grab a given signal - attempting to grab the |
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578 | same signal from two EV loops will crash the program immediately or |
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579 | cause data corruption. |
529 | |
580 | |
530 | EV will grab the signal for the process (the kernel only allows one |
581 | EV will grab the signal for the process (the kernel only allows one |
531 | component to receive a signal at a time) when you start a signal |
582 | component to receive a signal at a time) when you start a signal |
532 | watcher, and removes it again when you stop it. Perl does the same |
583 | watcher, and removes it again when you stop it. Perl does the same |
533 | when you add/remove callbacks to %SIG, so watch out. |
584 | when you add/remove callbacks to %SIG, so watch out. |
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748 | # make the dispatcher handle any new stuff |
799 | # make the dispatcher handle any new stuff |
749 | ... not shown |
800 | ... not shown |
750 | }; |
801 | }; |
751 | |
802 | |
752 | The callbacks of the created watchers will not be called as the |
803 | The callbacks of the created watchers will not be called as the |
753 | watchers are destroyed before this cna happen (remember EV::check |
804 | watchers are destroyed before this can happen (remember EV::check |
754 | gets called first). |
805 | gets called first). |
755 | |
806 | |
756 | The "check_ns" variant doesn't start (activate) the newly created |
807 | The "check_ns" variant doesn't start (activate) the newly created |
757 | watcher. |
808 | watcher. |
758 | |
809 | |
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783 | |
834 | |
784 | In short, this watcher is most useful on BSD systems without working |
835 | In short, this watcher is most useful on BSD systems without working |
785 | kqueue to still be able to handle a large number of sockets: |
836 | kqueue to still be able to handle a large number of sockets: |
786 | |
837 | |
787 | my $socket_loop; |
838 | my $socket_loop; |
788 | |
839 | |
789 | # check wether we use SELECT or POLL _and_ KQUEUE is supported |
840 | # check wether we use SELECT or POLL _and_ KQUEUE is supported |
790 | if ( |
841 | if ( |
791 | (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) |
842 | (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) |
792 | && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) |
843 | && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) |
793 | ) { |
844 | ) { |
794 | # use kqueue for sockets |
845 | # use kqueue for sockets |
795 | $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; |
846 | $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; |
796 | } |
847 | } |
797 | |
848 | |
798 | # use the default loop otherwise |
849 | # use the default loop otherwise |
799 | $socket_loop ||= EV::default_loop; |
850 | $socket_loop ||= EV::default_loop; |
800 | |
851 | |
801 | $w = EV::embed $otherloop[, $callback] |
852 | $w = EV::embed $otherloop[, $callback] |
802 | $w = EV::embed_ns $otherloop[, $callback] |
853 | $w = EV::embed_ns $otherloop[, $callback] |
803 | $w = $loop->embed ($otherloop[, $callback]) |
854 | $w = $loop->embed ($otherloop[, $callback]) |
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810 | The "embed_ns" variant doesn't start (activate) the newly created |
861 | The "embed_ns" variant doesn't start (activate) the newly created |
811 | watcher. |
862 | watcher. |
812 | |
863 | |
813 | ASYNC WATCHERS - how to wake up another event loop |
864 | ASYNC WATCHERS - how to wake up another event loop |
814 | Async watchers are provided by EV, but have little use in perl directly, |
865 | Async watchers are provided by EV, but have little use in perl directly, |
815 | as perl neither supports threads nor direct access to signal handlers or |
866 | as perl neither supports threads running in parallel nor direct access |
816 | other contexts where they could be of value. |
867 | to signal handlers or other contexts where they could be of value. |
817 | |
868 | |
818 | It is, however, possible to use them from the XS level. |
869 | It is, however, possible to use them from the XS level. |
819 | |
870 | |
820 | Please see the libev documentation for further details. |
871 | Please see the libev documentation for further details. |
821 | |
872 | |
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840 | my $async_check = EV::check sub { }; |
891 | my $async_check = EV::check sub { }; |
841 | |
892 | |
842 | This ensures that perl gets into control for a short time to handle any |
893 | This ensures that perl gets into control for a short time to handle any |
843 | pending signals, and also ensures (slightly) slower overall operation. |
894 | pending signals, and also ensures (slightly) slower overall operation. |
844 | |
895 | |
845 | THREADS |
896 | ITHREADS |
846 | Threads are not supported by this module in any way. Perl pseudo-threads |
897 | Ithreads are not supported by this module in any way. Perl |
847 | is evil stuff and must die. As soon as Perl gains real threads I will |
898 | pseudo-threads is evil stuff and must die. Real threads as provided by |
848 | work on thread support for it. |
899 | Coro are fully supported (and enhanced support is available via |
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900 | Coro::EV). |
849 | |
901 | |
850 | FORK |
902 | FORK |
851 | Most of the "improved" event delivering mechanisms of modern operating |
903 | Most of the "improved" event delivering mechanisms of modern operating |
852 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
904 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
853 | not supported and usually destructive). Libev makes it possible to work |
905 | not supported and usually destructive). Libev makes it possible to work |