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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 |
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54 | |
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55 | BEFORE YOU START USING THIS MODULE |
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56 | If you only need timer, I/O, signal, child and idle watchers and not the |
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57 | advanced functionality of this module, consider using AnyEvent instead, |
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58 | specifically the simplified API described in AE. |
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59 | |
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60 | When used with EV as backend, the AE API is as fast as the native EV |
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61 | API, but your programs/modules will still run with many other event |
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62 | loops. |
| 54 | |
63 | |
| 55 | DESCRIPTION |
64 | DESCRIPTION |
| 56 | This module provides an interface to libev |
65 | This module provides an interface to libev |
| 57 | (<http://software.schmorp.de/pkg/libev.html>). While the documentation |
66 | (<http://software.schmorp.de/pkg/libev.html>). While the documentation |
| 58 | below is comprehensive, one might also consult the documentation of |
67 | below is comprehensive, one might also consult the documentation of |
| … | |
… | |
| 235 | Otherwise a EV::timer with this value will be started. |
244 | Otherwise a EV::timer with this value will be started. |
| 236 | |
245 | |
| 237 | When an error occurs or either the timeout or I/O watcher triggers, |
246 | When an error occurs or either the timeout or I/O watcher triggers, |
| 238 | then the callback will be called with the received event set (in |
247 | then the callback will be called with the received event set (in |
| 239 | general you can expect it to be a combination of "EV::ERROR", |
248 | general you can expect it to be a combination of "EV::ERROR", |
| 240 | "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). |
249 | "EV::READ", "EV::WRITE" and "EV::TIMER"). |
| 241 | |
250 | |
| 242 | EV::once doesn't return anything: the watchers stay active till |
251 | EV::once doesn't return anything: the watchers stay active till |
| 243 | either of them triggers, then they will be stopped and freed, and |
252 | either of them triggers, then they will be stopped and freed, and |
| 244 | the callback invoked. |
253 | the callback invoked. |
| 245 | |
254 | |
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| 263 | the libev documentation at |
272 | the libev documentation at |
| 264 | <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT |
273 | <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT |
| 265 | ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more |
274 | ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more |
| 266 | detailed discussion. |
275 | detailed discussion. |
| 267 | |
276 | |
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277 | $count = EV::pending_count |
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278 | $count = $loop->pending_count |
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279 | Returns the number of currently pending watchers. |
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280 | |
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281 | EV::invoke_pending |
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282 | $loop->invoke_pending |
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283 | Invoke all currently pending watchers. |
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284 | |
| 268 | WATCHER OBJECTS |
285 | WATCHER OBJECTS |
| 269 | A watcher is an object that gets created to record your interest in some |
286 | A watcher is an object that gets created to record your interest in some |
| 270 | event. For instance, if you want to wait for STDIN to become readable, |
287 | event. For instance, if you want to wait for STDIN to become readable, |
| 271 | you would create an EV::io watcher for that: |
288 | you would create an EV::io watcher for that: |
| 272 | |
289 | |
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| 282 | |
299 | |
| 283 | Each watcher type has its associated bit in revents, so you can use the |
300 | Each watcher type has its associated bit in revents, so you can use the |
| 284 | same callback for multiple watchers. The event mask is named after the |
301 | same callback for multiple watchers. The event mask is named after the |
| 285 | type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
302 | type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
| 286 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O |
303 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O |
| 287 | events (which can set both EV::READ and EV::WRITE bits), and EV::timer |
304 | events (which can set both EV::READ and EV::WRITE bits). |
| 288 | (which uses EV::TIMEOUT). |
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| 289 | |
305 | |
| 290 | In the rare case where one wants to create a watcher but not start it at |
306 | In the rare case where one wants to create a watcher but not start it at |
| 291 | the same time, each constructor has a variant with a trailing "_ns" in |
307 | the same time, each constructor has a variant with a trailing "_ns" in |
| 292 | its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. |
308 | its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. |
| 293 | |
309 | |
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| 358 | the watcher isn't pending it does nothing and returns 0. |
374 | the watcher isn't pending it does nothing and returns 0. |
| 359 | |
375 | |
| 360 | $previous_state = $w->keepalive ($bool) |
376 | $previous_state = $w->keepalive ($bool) |
| 361 | Normally, "EV::loop" will return when there are no active watchers |
377 | Normally, "EV::loop" will return when there are no active watchers |
| 362 | (which is a "deadlock" because no progress can be made anymore). |
378 | (which is a "deadlock" because no progress can be made anymore). |
| 363 | This is convinient because it allows you to start your watchers (and |
379 | This is convenient because it allows you to start your watchers (and |
| 364 | your jobs), call "EV::loop" once and when it returns you know that |
380 | your jobs), call "EV::loop" once and when it returns you know that |
| 365 | all your jobs are finished (or they forgot to register some watchers |
381 | all your jobs are finished (or they forgot to register some watchers |
| 366 | for their task :). |
382 | for their task :). |
| 367 | |
383 | |
| 368 | Sometimes, however, this gets in your way, for example when the |
384 | Sometimes, however, this gets in your way, for example when the |
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| 559 | Return the time that the watcher is expected to trigger next. |
575 | Return the time that the watcher is expected to trigger next. |
| 560 | |
576 | |
| 561 | SIGNAL WATCHERS - signal me when a signal gets signalled! |
577 | SIGNAL WATCHERS - signal me when a signal gets signalled! |
| 562 | $w = EV::signal $signal, $callback |
578 | $w = EV::signal $signal, $callback |
| 563 | $w = EV::signal_ns $signal, $callback |
579 | $w = EV::signal_ns $signal, $callback |
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580 | $w = $loop->signal ($signal, $callback) |
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581 | $w = $loop->signal_ns ($signal, $callback) |
| 564 | Call the callback when $signal is received (the signal can be |
582 | Call the callback when $signal is received (the signal can be |
| 565 | specified by number or by name, just as with "kill" or %SIG). |
583 | specified by number or by name, just as with "kill" or %SIG). |
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584 | |
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585 | Only one event loop can grab a given signal - attempting to grab the |
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586 | same signal from two EV loops will crash the program immediately or |
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587 | cause data corruption. |
| 566 | |
588 | |
| 567 | EV will grab the signal for the process (the kernel only allows one |
589 | EV will grab the signal for the process (the kernel only allows one |
| 568 | component to receive a signal at a time) when you start a signal |
590 | component to receive a signal at a time) when you start a signal |
| 569 | watcher, and removes it again when you stop it. Perl does the same |
591 | watcher, and removes it again when you stop it. Perl does the same |
| 570 | when you add/remove callbacks to %SIG, so watch out. |
592 | when you add/remove callbacks to %SIG, so watch out. |
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| 820 | |
842 | |
| 821 | In short, this watcher is most useful on BSD systems without working |
843 | In short, this watcher is most useful on BSD systems without working |
| 822 | kqueue to still be able to handle a large number of sockets: |
844 | kqueue to still be able to handle a large number of sockets: |
| 823 | |
845 | |
| 824 | my $socket_loop; |
846 | my $socket_loop; |
| 825 | |
847 | |
| 826 | # check wether we use SELECT or POLL _and_ KQUEUE is supported |
848 | # check wether we use SELECT or POLL _and_ KQUEUE is supported |
| 827 | if ( |
849 | if ( |
| 828 | (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) |
850 | (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) |
| 829 | && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) |
851 | && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) |
| 830 | ) { |
852 | ) { |
| 831 | # use kqueue for sockets |
853 | # use kqueue for sockets |
| 832 | $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; |
854 | $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; |
| 833 | } |
855 | } |
| 834 | |
856 | |
| 835 | # use the default loop otherwise |
857 | # use the default loop otherwise |
| 836 | $socket_loop ||= EV::default_loop; |
858 | $socket_loop ||= EV::default_loop; |
| 837 | |
859 | |
| 838 | $w = EV::embed $otherloop[, $callback] |
860 | $w = EV::embed $otherloop[, $callback] |
| 839 | $w = EV::embed_ns $otherloop[, $callback] |
861 | $w = EV::embed_ns $otherloop[, $callback] |
| 840 | $w = $loop->embed ($otherloop[, $callback]) |
862 | $w = $loop->embed ($otherloop[, $callback]) |
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| 847 | The "embed_ns" variant doesn't start (activate) the newly created |
869 | The "embed_ns" variant doesn't start (activate) the newly created |
| 848 | watcher. |
870 | watcher. |
| 849 | |
871 | |
| 850 | ASYNC WATCHERS - how to wake up another event loop |
872 | ASYNC WATCHERS - how to wake up another event loop |
| 851 | Async watchers are provided by EV, but have little use in perl directly, |
873 | Async watchers are provided by EV, but have little use in perl directly, |
| 852 | as perl neither supports threads nor direct access to signal handlers or |
874 | as perl neither supports threads running in parallel nor direct access |
| 853 | other contexts where they could be of value. |
875 | to signal handlers or other contexts where they could be of value. |
| 854 | |
876 | |
| 855 | It is, however, possible to use them from the XS level. |
877 | It is, however, possible to use them from the XS level. |
| 856 | |
878 | |
| 857 | Please see the libev documentation for further details. |
879 | Please see the libev documentation for further details. |
| 858 | |
880 | |
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| 877 | my $async_check = EV::check sub { }; |
899 | my $async_check = EV::check sub { }; |
| 878 | |
900 | |
| 879 | This ensures that perl gets into control for a short time to handle any |
901 | This ensures that perl gets into control for a short time to handle any |
| 880 | pending signals, and also ensures (slightly) slower overall operation. |
902 | pending signals, and also ensures (slightly) slower overall operation. |
| 881 | |
903 | |
| 882 | THREADS |
904 | ITHREADS |
| 883 | Threads are not supported by this module in any way. Perl pseudo-threads |
905 | Ithreads are not supported by this module in any way. Perl |
| 884 | is evil stuff and must die. As soon as Perl gains real threads I will |
906 | pseudo-threads is evil stuff and must die. Real threads as provided by |
| 885 | work on thread support for it. |
907 | Coro are fully supported (and enhanced support is available via |
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908 | Coro::EV). |
| 886 | |
909 | |
| 887 | FORK |
910 | FORK |
| 888 | Most of the "improved" event delivering mechanisms of modern operating |
911 | Most of the "improved" event delivering mechanisms of modern operating |
| 889 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
912 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
| 890 | not supported and usually destructive). Libev makes it possible to work |
913 | not supported and usually destructive). Libev makes it possible to work |
