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Revision 1.32 by root, Tue Apr 28 00:50:57 2009 UTC vs.
Revision 1.39 by root, Tue Jan 11 13:45:28 2011 UTC

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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
5SYNOPSIS 5SYNOPSIS
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 };
23
23 24 # IO
24 # IO 25
25
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
55BEFORE YOU START USING THIS MODULE
56 If you only need timer, I/O, signal, child and idle watchers and not the
57 advanced functionality of this module, consider using AnyEvent instead,
58 specifically the simplified API described in AE.
59
60 When used with EV as backend, the AE API is as fast as the native EV
61 API, but your programs/modules will still run with many other event
62 loops.
54 63
55DESCRIPTION 64DESCRIPTION
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
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66 can use it through the AnyEvent module, stay portable to other event 75 can use it through the AnyEvent module, stay portable to other event
67 loops (if you don't rely on any watcher types not available through it) 76 loops (if you don't rely on any watcher types not available through it)
68 and still be faster than with any other event loop currently supported 77 and still be faster than with any other event loop currently supported
69 in Perl. 78 in Perl.
70 79
80 PORTING FROM EV 3.X to 4.X
81 EV version 4 introduces a number of incompatible changes summarised
82 here. According to the depreciation strategy used by libev, there is a
83 compatibility layer in place so programs should continue to run
84 unchanged (the XS interface lacks this layer, so programs using that one
85 need to be updated).
86
87 This compatibility layer will be switched off in some future release.
88
89 All changes relevant to Perl are renames of symbols, functions and
90 methods:
91
92 EV::loop => EV::run
93 EV::LOOP_NONBLOCK => EV::RUN_NOWAIT
94 EV::LOOP_ONESHOT => EV::RUN_ONCE
95
96 EV::unloop => EV::break
97 EV::UNLOOP_CANCEL => EV::BREAK_CANCEL
98 EV::UNLOOP_ONE => EV::BREAK_ONE
99 EV::UNLOOP_ALL => EV::BREAK_ALL
100
101 EV::TIMEOUT => EV::TIMER
102
103 EV::loop_count => EV::iteration
104 EV::loop_depth => EV::depth
105 EV::loop_verify => EV::verify
106
107 The loop object methods corresponding to the functions above have been
108 similarly renamed.
109
71 MODULE EXPORTS 110 MODULE EXPORTS
72 This module does not export any symbols. 111 This module does not export any symbols.
73 112
74EVENT LOOPS 113EVENT LOOPS
75 EV supports multiple event loops: There is a single "default event loop" 114 EV supports multiple event loops: There is a single "default event loop"
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201 Begin checking for events and calling callbacks. It returns when a 240 Begin checking for events and calling callbacks. It returns when a
202 callback calls EV::unloop. 241 callback calls EV::unloop.
203 242
204 The $flags argument can be one of the following: 243 The $flags argument can be one of the following:
205 244
206 0 as above 245 0 as above
207 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 246 EV::LOOP_ONCE block at most once (wait, but do not loop)
208 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 247 EV::LOOP_NOWAIT do not block at all (fetch/handle events but do not wait)
209 248
210 EV::unloop [$how] 249 EV::break [$how]
211 $loop->unloop ([$how]) 250 $loop->break ([$how])
212 When called with no arguments or an argument of EV::UNLOOP_ONE, 251 When called with no arguments or an argument of EV::BREAK_ONE, makes
213 makes the innermost call to EV::loop return. 252 the innermost call to EV::loop return.
214 253
215 When called with an argument of EV::UNLOOP_ALL, all calls to 254 When called with an argument of EV::BREAK_ALL, all calls to EV::loop
216 EV::loop will return as fast as possible. 255 will return as fast as possible.
256
257 When called with an argument of EV::BREAK_CANCEL, any pending break
258 will be cancelled.
217 259
218 $count = EV::loop_count 260 $count = EV::loop_count
219 $count = $loop->loop_count 261 $count = $loop->loop_count
220 Return the number of times the event loop has polled for new events. 262 Return the number of times the event loop has polled for new events.
221 Sometimes useful as a generation counter. 263 Sometimes useful as a generation counter.
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235 Otherwise a EV::timer with this value will be started. 277 Otherwise a EV::timer with this value will be started.
236 278
237 When an error occurs or either the timeout or I/O watcher triggers, 279 When an error occurs or either the timeout or I/O watcher triggers,
238 then the callback will be called with the received event set (in 280 then the callback will be called with the received event set (in
239 general you can expect it to be a combination of "EV::ERROR", 281 general you can expect it to be a combination of "EV::ERROR",
240 "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). 282 "EV::READ", "EV::WRITE" and "EV::TIMER").
241 283
242 EV::once doesn't return anything: the watchers stay active till 284 EV::once doesn't return anything: the watchers stay active till
243 either of them triggers, then they will be stopped and freed, and 285 either of them triggers, then they will be stopped and freed, and
244 the callback invoked. 286 the callback invoked.
245 287
246 EV::feed_fd_event ($fd, $revents) 288 EV::feed_fd_event $fd, $revents
247 $loop->feed_fd_event ($fd, $revents) 289 $loop->feed_fd_event ($fd, $revents)
248 Feed an event on a file descriptor into EV. EV will react to this 290 Feed an event on a file descriptor into EV. EV will react to this
249 call as if the readyness notifications specified by $revents (a 291 call as if the readyness notifications specified by $revents (a
250 combination of "EV::READ" and "EV::WRITE") happened on the file 292 combination of "EV::READ" and "EV::WRITE") happened on the file
251 descriptor $fd. 293 descriptor $fd.
252 294
253 EV::feed_signal_event ($signal) 295 EV::feed_signal_event $signal
254 Feed a signal event into EV. EV will react to this call as if the 296 Feed a signal event into the default loop. EV will react to this
255 signal specified by $signal had occured. 297 call as if the signal specified by $signal had occured.
298
299 EV::feed_signal $signal
300 Feed a signal event into EV - unlike "EV::feed_signal_event", this
301 works regardless of which loop has registered the signal, and is
302 mainly useful fro custom signal implementations.
256 303
257 EV::set_io_collect_interval $time 304 EV::set_io_collect_interval $time
258 $loop->set_io_collect_interval ($time) 305 $loop->set_io_collect_interval ($time)
259 EV::set_timeout_collect_interval $time 306 EV::set_timeout_collect_interval $time
260 $loop->set_timeout_collect_interval ($time) 307 $loop->set_timeout_collect_interval ($time)
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263 the libev documentation at 310 the libev documentation at
264 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT 311 <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 312 ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more
266 detailed discussion. 313 detailed discussion.
267 314
315 $count = EV::pending_count
316 $count = $loop->pending_count
317 Returns the number of currently pending watchers.
318
319 EV::invoke_pending
320 $loop->invoke_pending
321 Invoke all currently pending watchers.
322
268WATCHER OBJECTS 323WATCHER OBJECTS
269 A watcher is an object that gets created to record your interest in some 324 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, 325 event. For instance, if you want to wait for STDIN to become readable,
271 you would create an EV::io watcher for that: 326 you would create an EV::io watcher for that:
272 327
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282 337
283 Each watcher type has its associated bit in revents, so you can use the 338 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 339 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, 340 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 341 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 342 events (which can set both EV::READ and EV::WRITE bits).
288 (which uses EV::TIMEOUT).
289 343
290 In the rare case where one wants to create a watcher but not start it at 344 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 345 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. 346 its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
293 347
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358 the watcher isn't pending it does nothing and returns 0. 412 the watcher isn't pending it does nothing and returns 0.
359 413
360 $previous_state = $w->keepalive ($bool) 414 $previous_state = $w->keepalive ($bool)
361 Normally, "EV::loop" will return when there are no active watchers 415 Normally, "EV::loop" will return when there are no active watchers
362 (which is a "deadlock" because no progress can be made anymore). 416 (which is a "deadlock" because no progress can be made anymore).
363 This is convinient because it allows you to start your watchers (and 417 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 418 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 419 all your jobs are finished (or they forgot to register some watchers
366 for their task :). 420 for their task :).
367 421
368 Sometimes, however, this gets in your way, for example when the 422 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. 613 Return the time that the watcher is expected to trigger next.
560 614
561 SIGNAL WATCHERS - signal me when a signal gets signalled! 615 SIGNAL WATCHERS - signal me when a signal gets signalled!
562 $w = EV::signal $signal, $callback 616 $w = EV::signal $signal, $callback
563 $w = EV::signal_ns $signal, $callback 617 $w = EV::signal_ns $signal, $callback
618 $w = $loop->signal ($signal, $callback)
619 $w = $loop->signal_ns ($signal, $callback)
564 Call the callback when $signal is received (the signal can be 620 Call the callback when $signal is received (the signal can be
565 specified by number or by name, just as with "kill" or %SIG). 621 specified by number or by name, just as with "kill" or %SIG).
622
623 Only one event loop can grab a given signal - attempting to grab the
624 same signal from two EV loops will crash the program immediately or
625 cause data corruption.
566 626
567 EV will grab the signal for the process (the kernel only allows one 627 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 628 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 629 watcher, and removes it again when you stop it. Perl does the same
570 when you add/remove callbacks to %SIG, so watch out. 630 when you add/remove callbacks to %SIG, so watch out.
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744 $w = $loop->check_ns ($callback) 804 $w = $loop->check_ns ($callback)
745 Call the callback just after the process wakes up again (after it 805 Call the callback just after the process wakes up again (after it
746 has gathered events), but before any other callbacks have been 806 has gathered events), but before any other callbacks have been
747 invoked. 807 invoked.
748 808
749 This is used to integrate other event-based software into the EV 809 This can be used to integrate other event-based software into the EV
750 mainloop: You register a prepare callback and in there, you create 810 mainloop: You register a prepare callback and in there, you create
751 io and timer watchers as required by the other software. Here is a 811 io and timer watchers as required by the other software. Here is a
752 real-world example of integrating Net::SNMP (with some details left 812 real-world example of integrating Net::SNMP (with some details left
753 out): 813 out):
754 814
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790 watchers are destroyed before this can happen (remember EV::check 850 watchers are destroyed before this can happen (remember EV::check
791 gets called first). 851 gets called first).
792 852
793 The "check_ns" variant doesn't start (activate) the newly created 853 The "check_ns" variant doesn't start (activate) the newly created
794 watcher. 854 watcher.
855
856 EV::CHECK constant issues
857 Like all other watcher types, there is a bitmask constant for use in
858 $revents and other places. The "EV::CHECK" is special as it has the
859 same name as the "CHECK" sub called by Perl. This doesn't cause big
860 issues on newer perls (beginning with 5.8.9), but it means thatthe
861 constant must be *inlined*, i.e. runtime calls will not work. That
862 means that as long as you always "use EV" and then "EV::CHECK" you
863 are on the safe side.
795 864
796 FORK WATCHERS - the audacity to resume the event loop after a fork 865 FORK WATCHERS - the audacity to resume the event loop after a fork
797 Fork watchers are called when a "fork ()" was detected. The invocation 866 Fork watchers are called when a "fork ()" was detected. The invocation
798 is done before the event loop blocks next and before "check" watchers 867 is done before the event loop blocks next and before "check" watchers
799 are being called, and only in the child after the fork. 868 are being called, and only in the child after the fork.
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820 889
821 In short, this watcher is most useful on BSD systems without working 890 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: 891 kqueue to still be able to handle a large number of sockets:
823 892
824 my $socket_loop; 893 my $socket_loop;
825 894
826 # check wether we use SELECT or POLL _and_ KQUEUE is supported 895 # check wether we use SELECT or POLL _and_ KQUEUE is supported
827 if ( 896 if (
828 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 897 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
829 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 898 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
830 ) { 899 ) {
831 # use kqueue for sockets 900 # use kqueue for sockets
832 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 901 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
833 } 902 }
834 903
835 # use the default loop otherwise 904 # use the default loop otherwise
836 $socket_loop ||= EV::default_loop; 905 $socket_loop ||= EV::default_loop;
837 906
838 $w = EV::embed $otherloop[, $callback] 907 $w = EV::embed $otherloop[, $callback]
839 $w = EV::embed_ns $otherloop[, $callback] 908 $w = EV::embed_ns $otherloop[, $callback]
840 $w = $loop->embed ($otherloop[, $callback]) 909 $w = $loop->embed ($otherloop[, $callback])
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847 The "embed_ns" variant doesn't start (activate) the newly created 916 The "embed_ns" variant doesn't start (activate) the newly created
848 watcher. 917 watcher.
849 918
850 ASYNC WATCHERS - how to wake up another event loop 919 ASYNC WATCHERS - how to wake up another event loop
851 Async watchers are provided by EV, but have little use in perl directly, 920 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 921 as perl neither supports threads running in parallel nor direct access
853 other contexts where they could be of value. 922 to signal handlers or other contexts where they could be of value.
854 923
855 It is, however, possible to use them from the XS level. 924 It is, however, possible to use them from the XS level.
856 925
857 Please see the libev documentation for further details. 926 Please see the libev documentation for further details.
858 927
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877 my $async_check = EV::check sub { }; 946 my $async_check = EV::check sub { };
878 947
879 This ensures that perl gets into control for a short time to handle any 948 This ensures that perl gets into control for a short time to handle any
880 pending signals, and also ensures (slightly) slower overall operation. 949 pending signals, and also ensures (slightly) slower overall operation.
881 950
882THREADS 951ITHREADS
883 Threads are not supported by this module in any way. Perl pseudo-threads 952 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 953 pseudo-threads is evil stuff and must die. Real threads as provided by
885 work on thread support for it. 954 Coro are fully supported (and enhanced support is available via
955 Coro::EV).
886 956
887FORK 957FORK
888 Most of the "improved" event delivering mechanisms of modern operating 958 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 959 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 960 not supported and usually destructive). Libev makes it possible to work
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900 970
901 On win32, there is no notion of fork so all this doesn't apply, of 971 On win32, there is no notion of fork so all this doesn't apply, of
902 course. 972 course.
903 973
904SEE ALSO 974SEE ALSO
905 EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event 975 EV::MakeMaker - MakeMaker interface to XS API, EV::ADNS (asynchronous
906 loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines 976 DNS), Glib::EV (makes Glib/Gtk2 use EV as event loop), EV::Glib (embed
907 with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop 977 Glib into EV), Coro::EV (efficient thread integration), Net::SNMP::EV
908 agnostic and portable event driven programming. 978 (asynchronous SNMP), AnyEvent for event-loop agnostic and portable event
979 driven programming.
909 980
910AUTHOR 981AUTHOR
911 Marc Lehmann <schmorp@schmorp.de> 982 Marc Lehmann <schmorp@schmorp.de>
912 http://home.schmorp.de/ 983 http://home.schmorp.de/
913 984

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