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Revision 1.54 by root, Tue Nov 27 07:27:10 2007 UTC vs.
Revision 1.129 by root, Thu Oct 21 15:13:42 2010 UTC

2 2
3EV - perl interface to libev, a high performance full-featured event loop 3EV - perl interface to libev, a high performance full-featured event loop
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use EV; 7 use EV;
8
9 # TIMERS
10
11 my $w = EV::timer 2, 0, sub {
12 warn "is called after 2s";
13 };
14
15 my $w = EV::timer 2, 2, sub {
16 warn "is called roughly every 2s (repeat = 2)";
17 };
18
19 undef $w; # destroy event watcher again
20
21 my $w = EV::periodic 0, 60, 0, sub {
22 warn "is called every minute, on the minute, exactly";
23 };
24
25 # IO
26
27 my $w = EV::io *STDIN, EV::READ, sub {
28 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29 warn "stdin is readable, you entered: ", <STDIN>;
30 };
31
32 # SIGNALS
33
34 my $w = EV::signal 'QUIT', sub {
35 warn "sigquit received\n";
36 };
37
38 # CHILD/PID STATUS CHANGES
8 39
9 # TIMERS 40 my $w = EV::child 666, 0, sub {
41 my ($w, $revents) = @_;
42 my $status = $w->rstatus;
43 };
10 44
11 my $w = EV::timer 2, 0, sub {
12 warn "is called after 2s";
13 };
14
15 my $w = EV::timer 2, 2, sub {
16 warn "is called roughly every 2s (repeat = 2)";
17 };
18
19 undef $w; # destroy event watcher again
20
21 my $w = EV::periodic 0, 60, 0, sub {
22 warn "is called every minute, on the minute, exactly";
23 };
24
25 # IO
26
27 my $w = EV::io *STDIN, EV::READ, sub {
28 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29 warn "stdin is readable, you entered: ", <STDIN>;
30 };
31
32 # SIGNALS
33
34 my $w = EV::signal 'QUIT', sub {
35 warn "sigquit received\n";
36 };
37
38 # CHILD/PID STATUS CHANGES
39
40 my $w = EV::child 666, sub {
41 my ($w, $revents) = @_;
42 my $status = $w->rstatus;
43 };
44
45 # STAT CHANGES 45 # STAT CHANGES
46 my $w = EV::stat "/etc/passwd", 10, sub { 46 my $w = EV::stat "/etc/passwd", 10, sub {
47 my ($w, $revents) = @_; 47 my ($w, $revents) = @_;
48 warn $w->path, " has changed somehow.\n"; 48 warn $w->path, " has changed somehow.\n";
49 }; 49 };
50 50
51 # MAINLOOP 51 # MAINLOOP
52 EV::loop; # loop until EV::unloop is called or all watchers stop 52 EV::loop; # loop until EV::unloop is called or all watchers stop
53 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled 53 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
54 EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block 54 EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
55
56=head1 BEFORE YOU START USING THIS MODULE
57
58If you only need timer, I/O, signal, child and idle watchers and not the
59advanced functionality of this module, consider using L<AnyEvent> instead,
60specifically the simplified API described in L<AE>.
61
62When used with EV as backend, the L<AE> API is as fast as the native L<EV>
63API, but your programs/modules will still run with many other event loops.
55 64
56=head1 DESCRIPTION 65=head1 DESCRIPTION
57 66
58This module provides an interface to libev 67This module provides an interface to libev
59(L<http://software.schmorp.de/pkg/libev.html>). While the documentation 68(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
60below is comprehensive, one might also consult the documentation of libev 69below is comprehensive, one might also consult the documentation of
61itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on 70libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
62watcher semantics or some discussion on the available backends, or how to 71F<perldoc EV::libev>) for more subtle details on watcher semantics or some
63force a specific backend with C<LIBEV_FLAGS>. 72discussion on the available backends, or how to force a specific backend
73with C<LIBEV_FLAGS>, or just about in any case because it has much more
74detailed information.
75
76This module is very fast and scalable. It is actually so fast that you
77can use it through the L<AnyEvent> module, stay portable to other event
78loops (if you don't rely on any watcher types not available through it)
79and still be faster than with any other event loop currently supported in
80Perl.
81
82=head2 PORTING FROM EV 3.X to 4.X
83
84EV version 4 introduces a number of incompatible changes summarised
85here. According to the depreciation strategy used by libev, there is a
86compatibility layer in place so programs should continue to run unchanged
87(the XS interface lacks this layer, so programs using that one need to be
88updated).
89
90This compatibility layer will be switched off in some future release.
91
92All changes relevant to Perl are renames of symbols, functions and
93methods:
94
95 EV::loop => EV::run
96 EV::LOOP_NONBLOCK => EV::RUN_NOWAIT
97 EV::LOOP_ONESHOT => EV::RUN_ONCE
98
99 EV::unloop => EV::break
100 EV::UNLOOP_CANCEL => EV::BREAK_CANCEL
101 EV::UNLOOP_ONE => EV::BREAK_ONE
102 EV::UNLOOP_ALL => EV::BREAK_ALL
103
104 EV::TIMEOUT => EV::TIMER
105
106 EV::loop_count => EV::iteration
107 EV::loop_depth => EV::depth
108 EV::loop_verify => EV::verify
109
110The loop object methods corresponding to the functions above have been
111similarly renamed.
112
113=head2 MODULE EXPORTS
114
115This module does not export any symbols.
64 116
65=cut 117=cut
66 118
67package EV; 119package EV;
68 120
69use strict; 121use common::sense;
70 122
71BEGIN { 123BEGIN {
72 our $VERSION = '1.4'; 124 our $VERSION = '4.00';
73 use XSLoader; 125 use XSLoader;
74 XSLoader::load "EV", $VERSION; 126 XSLoader::load "EV", $VERSION;
75} 127}
76 128
77@EV::IO::ISA = 129@EV::IO::ISA =
78@EV::Timer::ISA = 130@EV::Timer::ISA =
79@EV::Periodic::ISA = 131@EV::Periodic::ISA =
80@EV::Signal::ISA = 132@EV::Signal::ISA =
133@EV::Child::ISA =
134@EV::Stat::ISA =
81@EV::Idle::ISA = 135@EV::Idle::ISA =
82@EV::Prepare::ISA = 136@EV::Prepare::ISA =
83@EV::Check::ISA = 137@EV::Check::ISA =
84@EV::Child::ISA =
85@EV::Embed::ISA = 138@EV::Embed::ISA =
86@EV::Stat::ISA = "EV::Watcher"; 139@EV::Fork::ISA =
140@EV::Async::ISA =
141 "EV::Watcher";
142
143@EV::Loop::Default::ISA = "EV::Loop";
144
145=head1 EVENT LOOPS
146
147EV supports multiple event loops: There is a single "default event loop"
148that can handle everything including signals and child watchers, and any
149number of "dynamic event loops" that can use different backends (with
150various limitations), but no child and signal watchers.
151
152You do not have to do anything to create the default event loop: When
153the module is loaded a suitable backend is selected on the premise of
154selecting a working backend (which for example rules out kqueue on most
155BSDs). Modules should, unless they have "special needs" always use the
156default loop as this is fastest (perl-wise), best supported by other
157modules (e.g. AnyEvent or Coro) and most portable event loop.
158
159For specific programs you can create additional event loops dynamically.
160
161If you want to take advantage of kqueue (which often works properly for
162sockets only) even though the default loop doesn't enable it, you can
163I<embed> a kqueue loop into the default loop: running the default loop
164will then also service the kqueue loop to some extent. See the example in
165the section about embed watchers for an example on how to achieve that.
166
167=over 4
168
169=item $loop = new EV::Loop [$flags]
170
171Create a new event loop as per the specified flags. Please refer to
172the C<ev_loop_new ()> function description in the libev documentation
173(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
174or locally-installed as F<EV::libev> manpage) for more info.
175
176The loop will automatically be destroyed when it is no longer referenced
177by any watcher and the loop object goes out of scope.
178
179If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
180is recommended, as only the default event loop is protected by this
181module. If you I<are> embedding this loop in the default loop, this is not
182necessary, as C<EV::embed> automatically does the right thing on fork.
183
184=item $loop->loop_fork
185
186Must be called after a fork in the child, before entering or continuing
187the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
188this function automatically, at some performance loss (refer to the libev
189documentation).
190
191=item $loop->loop_verify
192
193Calls C<ev_verify> to make internal consistency checks (for debugging
194libev) and abort the program if any data structures were found to be
195corrupted.
196
197=item $loop = EV::default_loop [$flags]
198
199Return the default loop (which is a singleton object). Since this module
200already creates the default loop with default flags, specifying flags here
201will not have any effect unless you destroy the default loop first, which
202isn't supported. So in short: don't do it, and if you break it, you get to
203keep the pieces.
204
205=back
206
87 207
88=head1 BASIC INTERFACE 208=head1 BASIC INTERFACE
89 209
90=over 4 210=over 4
91 211
92=item $EV::DIED 212=item $EV::DIED
93 213
94Must contain a reference to a function that is called when a callback 214Must contain a reference to a function that is called when a callback
95throws an exception (with $@ containing thr error). The default prints an 215throws an exception (with $@ containing the error). The default prints an
96informative message and continues. 216informative message and continues.
97 217
98If this callback throws an exception it will be silently ignored. 218If this callback throws an exception it will be silently ignored.
99 219
220=item $flags = EV::supported_backends
221
222=item $flags = EV::recommended_backends
223
224=item $flags = EV::embeddable_backends
225
226Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
227instance of EV, the set of recommended backends (supposed to be good) for
228this platform and the set of embeddable backends (see EMBED WATCHERS).
229
230=item EV::sleep $seconds
231
232Block the process for the given number of (fractional) seconds.
233
100=item $time = EV::time 234=item $time = EV::time
101 235
102Returns the current time in (fractional) seconds since the epoch. 236Returns the current time in (fractional) seconds since the epoch.
103 237
104=item $time = EV::now 238=item $time = EV::now
105 239
240=item $time = $loop->now
241
106Returns the time the last event loop iteration has been started. This 242Returns the time the last event loop iteration has been started. This
107is the time that (relative) timers are based on, and refering to it is 243is the time that (relative) timers are based on, and referring to it is
108usually faster then calling EV::time. 244usually faster then calling EV::time.
109 245
110=item $method = EV::method 246=item EV::now_update
111 247
248=item $loop->now_update
249
250Establishes the current time by querying the kernel, updating the time
251returned by C<EV::now> in the progress. This is a costly operation and
252is usually done automatically within C<EV::loop>.
253
254This function is rarely useful, but when some event callback runs for a
255very long time without entering the event loop, updating libev's idea of
256the current time is a good idea.
257
258=item EV::suspend
259
260=item $loop->suspend
261
262=item EV::resume
263
264=item $loop->resume
265
266These two functions suspend and resume a loop, for use when the loop is
267not used for a while and timeouts should not be processed.
268
269A typical use case would be an interactive program such as a game: When
270the user presses C<^Z> to suspend the game and resumes it an hour later it
271would be best to handle timeouts as if no time had actually passed while
272the program was suspended. This can be achieved by calling C<suspend>
273in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
274C<resume> directly afterwards to resume timer processing.
275
276Effectively, all C<timer> watchers will be delayed by the time spend
277between C<suspend> and C<resume>, and all C<periodic> watchers
278will be rescheduled (that is, they will lose any events that would have
279occured while suspended).
280
281After calling C<suspend> you B<must not> call I<any> function on the given
282loop other than C<resume>, and you B<must not> call C<resume>
283without a previous call to C<suspend>.
284
285Calling C<suspend>/C<resume> has the side effect of updating the event
286loop time (see C<now_update>).
287
288=item $backend = EV::backend
289
290=item $backend = $loop->backend
291
112Returns an integer describing the backend used by libev (EV::METHOD_SELECT 292Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
113or EV::METHOD_EPOLL). 293or EV::BACKEND_EPOLL).
114 294
115=item EV::loop [$flags] 295=item EV::loop [$flags]
296
297=item $loop->loop ([$flags])
116 298
117Begin checking for events and calling callbacks. It returns when a 299Begin checking for events and calling callbacks. It returns when a
118callback calls EV::unloop. 300callback calls EV::unloop.
119 301
120The $flags argument can be one of the following: 302The $flags argument can be one of the following:
123 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 305 EV::LOOP_ONESHOT block at most once (wait, but do not loop)
124 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 306 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
125 307
126=item EV::unloop [$how] 308=item EV::unloop [$how]
127 309
310=item $loop->unloop ([$how])
311
128When called with no arguments or an argument of EV::UNLOOP_ONE, makes the 312When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
129innermost call to EV::loop return. 313innermost call to EV::loop return.
130 314
131When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as 315When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
132fast as possible. 316fast as possible.
133 317
318=item $count = EV::loop_count
319
320=item $count = $loop->loop_count
321
322Return the number of times the event loop has polled for new
323events. Sometimes useful as a generation counter.
324
134=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 325=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
326
327=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
135 328
136This function rolls together an I/O and a timer watcher for a single 329This function rolls together an I/O and a timer watcher for a single
137one-shot event without the need for managing a watcher object. 330one-shot event without the need for managing a watcher object.
138 331
139If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> 332If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
145If timeout is C<undef> or negative, then there will be no 338If timeout is C<undef> or negative, then there will be no
146timeout. Otherwise a EV::timer with this value will be started. 339timeout. Otherwise a EV::timer with this value will be started.
147 340
148When an error occurs or either the timeout or I/O watcher triggers, then 341When an error occurs or either the timeout or I/O watcher triggers, then
149the callback will be called with the received event set (in general 342the callback will be called with the received event set (in general
150you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>, 343you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
151C<EV::WRITE> and C<EV::TIMEOUT>). 344C<EV::WRITE> and C<EV::TIMER>).
152 345
153EV::once doesn't return anything: the watchers stay active till either 346EV::once doesn't return anything: the watchers stay active till either
154of them triggers, then they will be stopped and freed, and the callback 347of them triggers, then they will be stopped and freed, and the callback
155invoked. 348invoked.
156 349
157=back 350=item EV::feed_fd_event ($fd, $revents)
158 351
352=item $loop->feed_fd_event ($fd, $revents)
353
354Feed an event on a file descriptor into EV. EV will react to this call as
355if the readyness notifications specified by C<$revents> (a combination of
356C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
357
358=item EV::feed_signal_event ($signal)
359
360Feed a signal event into EV. EV will react to this call as if the signal
361specified by C<$signal> had occured.
362
363=item EV::set_io_collect_interval $time
364
365=item $loop->set_io_collect_interval ($time)
366
367=item EV::set_timeout_collect_interval $time
368
369=item $loop->set_timeout_collect_interval ($time)
370
371These advanced functions set the minimum block interval when polling for I/O events and the minimum
372wait interval for timer events. See the libev documentation at
373L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
374(locally installed as F<EV::libev>) for a more detailed discussion.
375
376=item $count = EV::pending_count
377
378=item $count = $loop->pending_count
379
380Returns the number of currently pending watchers.
381
382=item EV::invoke_pending
383
384=item $loop->invoke_pending
385
386Invoke all currently pending watchers.
387
388=back
389
390
159=head2 WATCHER OBJECTS 391=head1 WATCHER OBJECTS
160 392
161A watcher is an object that gets created to record your interest in some 393A watcher is an object that gets created to record your interest in some
162event. For instance, if you want to wait for STDIN to become readable, you 394event. For instance, if you want to wait for STDIN to become readable, you
163would create an EV::io watcher for that: 395would create an EV::io watcher for that:
164 396
165 my $watcher = EV::io *STDIN, EV::READ, sub { 397 my $watcher = EV::io *STDIN, EV::READ, sub {
166 my ($watcher, $revents) = @_; 398 my ($watcher, $revents) = @_;
167 warn "yeah, STDIN should not be readable without blocking!\n" 399 warn "yeah, STDIN should now be readable without blocking!\n"
168 }; 400 };
169 401
170All watchers can be active (waiting for events) or inactive (paused). Only 402All watchers can be active (waiting for events) or inactive (paused). Only
171active watchers will have their callbacks invoked. All callbacks will be 403active watchers will have their callbacks invoked. All callbacks will be
172called with at least two arguments: the watcher and a bitmask of received 404called with at least two arguments: the watcher and a bitmask of received
173events. 405events.
174 406
175Each watcher type has its associated bit in revents, so you can use the 407Each watcher type has its associated bit in revents, so you can use the
176same callback for multiple watchers. The event mask is named after the 408same callback for multiple watchers. The event mask is named after the
177type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 409type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
178EV::periodic sets EV::PERIODIC and so on, with the exception of IO events 410EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
179(which can set both EV::READ and EV::WRITE bits), and EV::timer (which 411(which can set both EV::READ and EV::WRITE bits).
180uses EV::TIMEOUT).
181 412
182In the rare case where one wants to create a watcher but not start it at 413In the rare case where one wants to create a watcher but not start it at
183the same time, each constructor has a variant with a trailing C<_ns> in 414the same time, each constructor has a variant with a trailing C<_ns> in
184its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. 415its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
185 416
205 436
206=item $w->stop 437=item $w->stop
207 438
208Stop a watcher if it is active. Also clear any pending events (events that 439Stop a watcher if it is active. Also clear any pending events (events that
209have been received but that didn't yet result in a callback invocation), 440have been received but that didn't yet result in a callback invocation),
210regardless of wether the watcher was active or not. 441regardless of whether the watcher was active or not.
211 442
212=item $bool = $w->is_active 443=item $bool = $w->is_active
213 444
214Returns true if the watcher is active, false otherwise. 445Returns true if the watcher is active, false otherwise.
215 446
245The default priority of any newly-created watcher is 0. 476The default priority of any newly-created watcher is 0.
246 477
247Note that the priority semantics have not yet been fleshed out and are 478Note that the priority semantics have not yet been fleshed out and are
248subject to almost certain change. 479subject to almost certain change.
249 480
250=item $w->trigger ($revents) 481=item $w->invoke ($revents)
251 482
252Call the callback *now* with the given event mask. 483Call the callback *now* with the given event mask.
484
485=item $w->feed_event ($revents)
486
487Feed some events on this watcher into EV. EV will react to this call as if
488the watcher had received the given C<$revents> mask.
489
490=item $revents = $w->clear_pending
491
492If the watcher is pending, this function clears its pending status and
493returns its C<$revents> bitset (as if its callback was invoked). If the
494watcher isn't pending it does nothing and returns C<0>.
253 495
254=item $previous_state = $w->keepalive ($bool) 496=item $previous_state = $w->keepalive ($bool)
255 497
256Normally, C<EV::loop> will return when there are no active watchers 498Normally, C<EV::loop> will return when there are no active watchers
257(which is a "deadlock" because no progress can be made anymore). This is 499(which is a "deadlock" because no progress can be made anymore). This is
258convinient because it allows you to start your watchers (and your jobs), 500convenient because it allows you to start your watchers (and your jobs),
259call C<EV::loop> once and when it returns you know that all your jobs are 501call C<EV::loop> once and when it returns you know that all your jobs are
260finished (or they forgot to register some watchers for their task :). 502finished (or they forgot to register some watchers for their task :).
261 503
262Sometimes, however, this gets in your way, for example when you the module 504Sometimes, however, this gets in your way, for example when the module
263that calls C<EV::loop> (usually the main program) is not the same module 505that calls C<EV::loop> (usually the main program) is not the same module
264as a long-living watcher (for example a DNS client module written by 506as a long-living watcher (for example a DNS client module written by
265somebody else even). Then you might want any outstanding requests to be 507somebody else even). Then you might want any outstanding requests to be
266handled, but you would not want to keep C<EV::loop> from returning just 508handled, but you would not want to keep C<EV::loop> from returning just
267because you happen to have this long-running UDP port watcher. 509because you happen to have this long-running UDP port watcher.
268 510
269In this case you can clear the keepalive status, which means that even 511In this case you can clear the keepalive status, which means that even
270though your watcher is active, it won't keep C<EV::loop> from returning. 512though your watcher is active, it won't keep C<EV::loop> from returning.
271 513
272The initial value for keepalive is true (enabled), and you cna change it 514The initial value for keepalive is true (enabled), and you can change it
273any time. 515any time.
274 516
275Example: Register an IO watcher for some UDP socket but do not keep the 517Example: Register an I/O watcher for some UDP socket but do not keep the
276event loop from running just because of that watcher. 518event loop from running just because of that watcher.
277 519
278 my $udp_socket = ... 520 my $udp_socket = ...
279 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 521 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
280 $udp_watcher->keepalive (0); 522 $udp_watcher->keepalive (0);
281 523
282=back 524=item $loop = $w->loop
283 525
526Return the loop that this watcher is attached to.
284 527
528=back
529
530
285=head2 WATCHER TYPES 531=head1 WATCHER TYPES
286 532
287Each of the following subsections describes a single watcher type. 533Each of the following subsections describes a single watcher type.
288 534
289=head3 IO WATCHERS - is this file descriptor readable or writable? 535=head3 I/O WATCHERS - is this file descriptor readable or writable?
290 536
291=over 4 537=over 4
292 538
293=item $w = EV::io $fileno_or_fh, $eventmask, $callback 539=item $w = EV::io $fileno_or_fh, $eventmask, $callback
294 540
295=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 541=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
542
543=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
544
545=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
296 546
297As long as the returned watcher object is alive, call the C<$callback> 547As long as the returned watcher object is alive, call the C<$callback>
298when at least one of events specified in C<$eventmask> occurs. 548when at least one of events specified in C<$eventmask> occurs.
299 549
300The $eventmask can be one or more of these constants ORed together: 550The $eventmask can be one or more of these constants ORed together:
329=over 4 579=over 4
330 580
331=item $w = EV::timer $after, $repeat, $callback 581=item $w = EV::timer $after, $repeat, $callback
332 582
333=item $w = EV::timer_ns $after, $repeat, $callback 583=item $w = EV::timer_ns $after, $repeat, $callback
584
585=item $w = $loop->timer ($after, $repeat, $callback)
586
587=item $w = $loop->timer_ns ($after, $repeat, $callback)
334 588
335Calls the callback after C<$after> seconds (which may be fractional). If 589Calls the callback after C<$after> seconds (which may be fractional). If
336C<$repeat> is non-zero, the timer will be restarted (with the $repeat 590C<$repeat> is non-zero, the timer will be restarted (with the $repeat
337value as $after) after the callback returns. 591value as $after) after the callback returns.
338 592
379=over 4 633=over 4
380 634
381=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback 635=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
382 636
383=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 637=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
638
639=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
640
641=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
384 642
385Similar to EV::timer, but is not based on relative timeouts but on 643Similar to EV::timer, but is not based on relative timeouts but on
386absolute times. Apart from creating "simple" timers that trigger "at" the 644absolute times. Apart from creating "simple" timers that trigger "at" the
387specified time, it can also be used for non-drifting absolute timers and 645specified time, it can also be used for non-drifting absolute timers and
388more complex, cron-like, setups that are not adversely affected by time 646more complex, cron-like, setups that are not adversely affected by time
398This time simply fires at the wallclock time C<$at> and doesn't repeat. It 656This time simply fires at the wallclock time C<$at> and doesn't repeat. It
399will not adjust when a time jump occurs, that is, if it is to be run 657will not adjust when a time jump occurs, that is, if it is to be run
400at January 1st 2011 then it will run when the system time reaches or 658at January 1st 2011 then it will run when the system time reaches or
401surpasses this time. 659surpasses this time.
402 660
403=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 661=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
404 662
405In this mode the watcher will always be scheduled to time out at the 663In this mode the watcher will always be scheduled to time out at the
406next C<$at + N * $interval> time (for some integer N) and then repeat, 664next C<$at + N * $interval> time (for some integer N) and then repeat,
407regardless of any time jumps. 665regardless of any time jumps.
408 666
426time the periodic watcher gets scheduled, the reschedule callback 684time the periodic watcher gets scheduled, the reschedule callback
427($reschedule_cb) will be called with the watcher as first, and the current 685($reschedule_cb) will be called with the watcher as first, and the current
428time as second argument. 686time as second argument.
429 687
430I<This callback MUST NOT stop or destroy this or any other periodic 688I<This callback MUST NOT stop or destroy this or any other periodic
431watcher, ever>. If you need to stop it, return 1e30 and stop it 689watcher, ever, and MUST NOT call any event loop functions or methods>. If
432afterwards. 690you need to stop it, return 1e30 and stop it afterwards. You may create
691and start a C<EV::prepare> watcher for this task.
433 692
434It must return the next time to trigger, based on the passed time value 693It must return the next time to trigger, based on the passed time value
435(that is, the lowest time value larger than to the second argument). It 694(that is, the lowest time value larger than or equal to to the second
436will usually be called just before the callback will be triggered, but 695argument). It will usually be called just before the callback will be
437might be called at other times, too. 696triggered, but might be called at other times, too.
438 697
439This can be used to create very complex timers, such as a timer that 698This can be used to create very complex timers, such as a timer that
440triggers on each midnight, local time (actually 24 hours after the last 699triggers on each midnight, local time (actually 24 hours after the last
441midnight, to keep the example simple. If you know a way to do it correctly 700midnight, to keep the example simple. If you know a way to do it correctly
442in about the same space (without requiring elaborate modules), drop me a 701in about the same space (without requiring elaborate modules), drop me a
463 722
464=item $w->again 723=item $w->again
465 724
466Simply stops and starts the watcher again. 725Simply stops and starts the watcher again.
467 726
727=item $time = $w->at
728
729Return the time that the watcher is expected to trigger next.
730
468=back 731=back
469 732
470 733
471=head3 SIGNAL WATCHERS - signal me when a signal gets signalled! 734=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
472 735
473=over 4 736=over 4
474 737
475=item $w = EV::signal $signal, $callback 738=item $w = EV::signal $signal, $callback
476 739
477=item $w = EV::signal_ns $signal, $callback 740=item $w = EV::signal_ns $signal, $callback
741
742=item $w = $loop->signal ($signal, $callback)
743
744=item $w = $loop->signal_ns ($signal, $callback)
478 745
479Call the callback when $signal is received (the signal can be specified by 746Call the callback when $signal is received (the signal can be specified by
480number or by name, just as with C<kill> or C<%SIG>). 747number or by name, just as with C<kill> or C<%SIG>).
748
749Only one event loop can grab a given signal - attempting to grab the same
750signal from two EV loops will crash the program immediately or cause data
751corruption.
481 752
482EV will grab the signal for the process (the kernel only allows one 753EV will grab the signal for the process (the kernel only allows one
483component to receive a signal at a time) when you start a signal watcher, 754component to receive a signal at a time) when you start a signal watcher,
484and removes it again when you stop it. Perl does the same when you 755and removes it again when you stop it. Perl does the same when you
485add/remove callbacks to C<%SIG>, so watch out. 756add/remove callbacks to C<%SIG>, so watch out.
505 776
506=head3 CHILD WATCHERS - watch out for process status changes 777=head3 CHILD WATCHERS - watch out for process status changes
507 778
508=over 4 779=over 4
509 780
510=item $w = EV::child $pid, $callback 781=item $w = EV::child $pid, $trace, $callback
511 782
512=item $w = EV::child_ns $pid, $callback 783=item $w = EV::child_ns $pid, $trace, $callback
513 784
785=item $w = $loop->child ($pid, $trace, $callback)
786
787=item $w = $loop->child_ns ($pid, $trace, $callback)
788
514Call the callback when a status change for pid C<$pid> (or any pid if 789Call the callback when a status change for pid C<$pid> (or any pid
515C<$pid> is 0) has been received. More precisely: when the process receives 790if C<$pid> is 0) has been received (a status change happens when the
791process terminates or is killed, or, when trace is true, additionally when
792it is stopped or continued). More precisely: when the process receives
516a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all 793a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
517changed/zombie children and call the callback. 794changed/zombie children and call the callback.
518 795
519It is valid (and fully supported) to install a child watcher after a child 796It is valid (and fully supported) to install a child watcher after a child
520has exited but before the event loop has started its next iteration (for 797has exited but before the event loop has started its next iteration (for
527You can have as many pid watchers per pid as you want, they will all be 804You can have as many pid watchers per pid as you want, they will all be
528called. 805called.
529 806
530The C<child_ns> variant doesn't start (activate) the newly created watcher. 807The C<child_ns> variant doesn't start (activate) the newly created watcher.
531 808
532=item $w->set ($pid) 809=item $w->set ($pid, $trace)
533 810
534Reconfigures the watcher, see the constructor above for details. Can be called at 811Reconfigures the watcher, see the constructor above for details. Can be called at
535any time. 812any time.
536 813
537=item $current_pid = $w->pid 814=item $current_pid = $w->pid
538 815
539=item $old_pid = $w->pid ($new_pid)
540
541Returns the previously set process id and optionally set a new one. 816Returns the previously set process id and optionally set a new one.
542 817
543=item $exit_status = $w->rstatus 818=item $exit_status = $w->rstatus
544 819
545Return the exit/wait status (as returned by waitpid, see the waitpid entry 820Return the exit/wait status (as returned by waitpid, see the waitpid entry
551watcher for all pids). 826watcher for all pids).
552 827
553=back 828=back
554 829
555 830
831=head3 STAT WATCHERS - did the file attributes just change?
832
833=over 4
834
835=item $w = EV::stat $path, $interval, $callback
836
837=item $w = EV::stat_ns $path, $interval, $callback
838
839=item $w = $loop->stat ($path, $interval, $callback)
840
841=item $w = $loop->stat_ns ($path, $interval, $callback)
842
843Call the callback when a file status change has been detected on
844C<$path>. The C<$path> does not need to exist, changing from "path exists"
845to "path does not exist" is a status change like any other.
846
847The C<$interval> is a recommended polling interval for systems where
848OS-supported change notifications don't exist or are not supported. If
849you use C<0> then an unspecified default is used (which is highly
850recommended!), which is to be expected to be around five seconds usually.
851
852This watcher type is not meant for massive numbers of stat watchers,
853as even with OS-supported change notifications, this can be
854resource-intensive.
855
856The C<stat_ns> variant doesn't start (activate) the newly created watcher.
857
858=item ... = $w->stat
859
860This call is very similar to the perl C<stat> built-in: It stats (using
861C<lstat>) the path specified in the watcher and sets perls stat cache (as
862well as EV's idea of the current stat values) to the values found.
863
864In scalar context, a boolean is return indicating success or failure of
865the stat. In list context, the same 13-value list as with stat is returned
866(except that the blksize and blocks fields are not reliable).
867
868In the case of an error, errno is set to C<ENOENT> (regardless of the
869actual error value) and the C<nlink> value is forced to zero (if the stat
870was successful then nlink is guaranteed to be non-zero).
871
872See also the next two entries for more info.
873
874=item ... = $w->attr
875
876Just like C<< $w->stat >>, but without the initial stat'ing: this returns
877the values most recently detected by EV. See the next entry for more info.
878
879=item ... = $w->prev
880
881Just like C<< $w->stat >>, but without the initial stat'ing: this returns
882the previous set of values, before the change.
883
884That is, when the watcher callback is invoked, C<< $w->prev >> will be set
885to the values found I<before> a change was detected, while C<< $w->attr >>
886returns the values found leading to the change detection. The difference (if any)
887between C<prev> and C<attr> is what triggered the callback.
888
889If you did something to the filesystem object and do not want to trigger
890yet another change, you can call C<stat> to update EV's idea of what the
891current attributes are.
892
893=item $w->set ($path, $interval)
894
895Reconfigures the watcher, see the constructor above for details. Can be
896called at any time.
897
898=item $current_path = $w->path
899
900=item $old_path = $w->path ($new_path)
901
902Returns the previously set path and optionally set a new one.
903
904=item $current_interval = $w->interval
905
906=item $old_interval = $w->interval ($new_interval)
907
908Returns the previously set interval and optionally set a new one. Can be
909used to query the actual interval used.
910
911=back
912
913
556=head3 IDLE WATCHERS - when you've got nothing better to do... 914=head3 IDLE WATCHERS - when you've got nothing better to do...
557 915
558=over 4 916=over 4
559 917
560=item $w = EV::idle $callback 918=item $w = EV::idle $callback
561 919
562=item $w = EV::idle_ns $callback 920=item $w = EV::idle_ns $callback
563 921
564Call the callback when there are no pending io, timer/periodic, signal or 922=item $w = $loop->idle ($callback)
565child events, i.e. when the process is idle. 923
924=item $w = $loop->idle_ns ($callback)
925
926Call the callback when there are no other pending watchers of the same or
927higher priority (excluding check, prepare and other idle watchers of the
928same or lower priority, of course). They are called idle watchers because
929when the watcher is the highest priority pending event in the process, the
930process is considered to be idle at that priority.
931
932If you want a watcher that is only ever called when I<no> other events are
933outstanding you have to set the priority to C<EV::MINPRI>.
566 934
567The process will not block as long as any idle watchers are active, and 935The process will not block as long as any idle watchers are active, and
568they will be called repeatedly until stopped. 936they will be called repeatedly until stopped.
569 937
938For example, if you have idle watchers at priority C<0> and C<1>, and
939an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
940and the I/O watcher will always run when ready. Only when the idle watcher
941at priority C<1> is stopped and the I/O watcher at priority C<0> is not
942pending with the C<0>-priority idle watcher be invoked.
943
570The C<idle_ns> variant doesn't start (activate) the newly created watcher. 944The C<idle_ns> variant doesn't start (activate) the newly created watcher.
571 945
572=back 946=back
573 947
574 948
577=over 4 951=over 4
578 952
579=item $w = EV::prepare $callback 953=item $w = EV::prepare $callback
580 954
581=item $w = EV::prepare_ns $callback 955=item $w = EV::prepare_ns $callback
956
957=item $w = $loop->prepare ($callback)
958
959=item $w = $loop->prepare_ns ($callback)
582 960
583Call the callback just before the process would block. You can still 961Call the callback just before the process would block. You can still
584create/modify any watchers at this point. 962create/modify any watchers at this point.
585 963
586See the EV::check watcher, below, for explanations and an example. 964See the EV::check watcher, below, for explanations and an example.
596 974
597=item $w = EV::check $callback 975=item $w = EV::check $callback
598 976
599=item $w = EV::check_ns $callback 977=item $w = EV::check_ns $callback
600 978
979=item $w = $loop->check ($callback)
980
981=item $w = $loop->check_ns ($callback)
982
601Call the callback just after the process wakes up again (after it has 983Call the callback just after the process wakes up again (after it has
602gathered events), but before any other callbacks have been invoked. 984gathered events), but before any other callbacks have been invoked.
603 985
604This is used to integrate other event-based software into the EV 986This can be used to integrate other event-based software into the EV
605mainloop: You register a prepare callback and in there, you create io and 987mainloop: You register a prepare callback and in there, you create io and
606timer watchers as required by the other software. Here is a real-world 988timer watchers as required by the other software. Here is a real-world
607example of integrating Net::SNMP (with some details left out): 989example of integrating Net::SNMP (with some details left out):
608 990
609 our @snmp_watcher; 991 our @snmp_watcher;
614 or return; 996 or return;
615 997
616 # make the dispatcher handle any outstanding stuff 998 # make the dispatcher handle any outstanding stuff
617 ... not shown 999 ... not shown
618 1000
619 # create an IO watcher for each and every socket 1001 # create an I/O watcher for each and every socket
620 @snmp_watcher = ( 1002 @snmp_watcher = (
621 (map { EV::io $_, EV::READ, sub { } } 1003 (map { EV::io $_, EV::READ, sub { } }
622 keys %{ $dispatcher->{_descriptors} }), 1004 keys %{ $dispatcher->{_descriptors} }),
623 1005
624 EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] 1006 EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
639 # make the dispatcher handle any new stuff 1021 # make the dispatcher handle any new stuff
640 ... not shown 1022 ... not shown
641 }; 1023 };
642 1024
643The callbacks of the created watchers will not be called as the watchers 1025The callbacks of the created watchers will not be called as the watchers
644are destroyed before this cna happen (remember EV::check gets called 1026are destroyed before this can happen (remember EV::check gets called
645first). 1027first).
646 1028
647The C<check_ns> variant doesn't start (activate) the newly created watcher. 1029The C<check_ns> variant doesn't start (activate) the newly created watcher.
648 1030
649=back 1031=item EV::CHECK constant issues
650 1032
651=head3 STAT WATCHERS - did the file stats just change? 1033Like all other watcher types, there is a bitmask constant for use in
1034C<$revents> and other places. The C<EV::CHECK> is special as it has
1035the same name as the C<CHECK> sub called by Perl. This doesn't cause
1036big issues on newer perls (beginning with 5.8.9), but it means thatthe
1037constant must be I<inlined>, i.e. runtime calls will not work. That means
1038that as long as you always C<use EV> and then C<EV::CHECK> you are on the
1039safe side.
652 1040
653=over 4 1041=back
654 1042
655=item $w = EV::stat $path, $interval, $callback
656 1043
657=item $w = EV::stat_ns $path, $interval, $callback 1044=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
658 1045
659Call the callback when a file status change has been detected on 1046Fork watchers are called when a C<fork ()> was detected. The invocation
660C<$path>. The C<$path> does not need to exist, changing from "path exists" 1047is done before the event loop blocks next and before C<check> watchers
661to "path does not exist" is a status change like any other. 1048are being called, and only in the child after the fork.
662 1049
663The C<$interval> is a recommended polling interval for systems where 1050=over 4
664OS-supported change notifications don't exist or are not supported. If
665you use C<0> then an unspecified default is used (which is highly
666recommended!), which is to be expected to be around five seconds usually.
667 1051
668This watcher type is not meant for massive numbers of stat watchers, 1052=item $w = EV::fork $callback
669as even with OS-supported change notifications, this can be
670resource-intensive.
671 1053
1054=item $w = EV::fork_ns $callback
1055
1056=item $w = $loop->fork ($callback)
1057
1058=item $w = $loop->fork_ns ($callback)
1059
1060Call the callback before the event loop is resumed in the child process
1061after a fork.
1062
672The C<stat_ns> variant doesn't start (activate) the newly created watcher. 1063The C<fork_ns> variant doesn't start (activate) the newly created watcher.
673 1064
674=item $w->set ($path, $interval)
675
676Reconfigures the watcher, see the constructor above for details. Can be
677called at any time.
678
679=item $current_path = $w->path
680
681=item $old_path = $w->path ($new_path)
682
683Returns the previously set path and optionally set a new one.
684
685=item $current_interval = $w->interval
686
687=item $old_interval = $w->interval ($new_interval)
688
689Returns the previously set interval and optionally set a new one. Can be
690used to query the actual interval used.
691
692=back 1065=back
693 1066
694 1067
1068=head3 EMBED WATCHERS - when one backend isn't enough...
1069
1070This is a rather advanced watcher type that lets you embed one event loop
1071into another (currently only IO events are supported in the embedded
1072loop, other types of watchers might be handled in a delayed or incorrect
1073fashion and must not be used).
1074
1075See the libev documentation at
1076L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
1077(locally installed as F<EV::libev>) for more details.
1078
1079In short, this watcher is most useful on BSD systems without working
1080kqueue to still be able to handle a large number of sockets:
1081
1082 my $socket_loop;
1083
1084 # check wether we use SELECT or POLL _and_ KQUEUE is supported
1085 if (
1086 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
1087 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
1088 ) {
1089 # use kqueue for sockets
1090 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
1091 }
1092
1093 # use the default loop otherwise
1094 $socket_loop ||= EV::default_loop;
1095
1096=over 4
1097
1098=item $w = EV::embed $otherloop[, $callback]
1099
1100=item $w = EV::embed_ns $otherloop[, $callback]
1101
1102=item $w = $loop->embed ($otherloop[, $callback])
1103
1104=item $w = $loop->embed_ns ($otherloop[, $callback])
1105
1106Call the callback when the embedded event loop (C<$otherloop>) has any
1107I/O activity. The C<$callback> is optional: if it is missing, then the
1108embedded event loop will be managed automatically (which is recommended),
1109otherwise you have to invoke C<sweep> yourself.
1110
1111The C<embed_ns> variant doesn't start (activate) the newly created watcher.
1112
1113=back
1114
1115=head3 ASYNC WATCHERS - how to wake up another event loop
1116
1117Async watchers are provided by EV, but have little use in perl directly,
1118as perl neither supports threads running in parallel nor direct access to
1119signal handlers or other contexts where they could be of value.
1120
1121It is, however, possible to use them from the XS level.
1122
1123Please see the libev documentation for further details.
1124
1125=over 4
1126
1127=item $w = EV::async $callback
1128
1129=item $w = EV::async_ns $callback
1130
1131=item $w->send
1132
1133=item $bool = $w->async_pending
1134
1135=back
1136
1137
1138=head1 PERL SIGNALS
1139
1140While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
1141with EV is as the same as any other C library: Perl-signals will only be
1142handled when Perl runs, which means your signal handler might be invoked
1143only the next time an event callback is invoked.
1144
1145The solution is to use EV signal watchers (see C<EV::signal>), which will
1146ensure proper operations with regards to other event watchers.
1147
1148If you cannot do this for whatever reason, you can also force a watcher
1149to be called on every event loop iteration by installing a C<EV::check>
1150watcher:
1151
1152 my $async_check = EV::check sub { };
1153
1154This ensures that perl gets into control for a short time to handle any
1155pending signals, and also ensures (slightly) slower overall operation.
1156
695=head1 THREADS 1157=head1 ITHREADS
696 1158
697Threads are not supported by this module in any way. Perl pseudo-threads 1159Ithreads are not supported by this module in any way. Perl pseudo-threads
698is evil stuff and must die. As soon as Perl gains real threads I will work 1160is evil stuff and must die. Real threads as provided by Coro are fully
699on thread support for it. 1161supported (and enhanced support is available via L<Coro::EV>).
700 1162
701=head1 FORK 1163=head1 FORK
702 1164
703Most of the "improved" event delivering mechanisms of modern operating 1165Most of the "improved" event delivering mechanisms of modern operating
704systems have quite a few problems with fork(2) (to put it bluntly: it is 1166systems have quite a few problems with fork(2) (to put it bluntly: it is
720our $DIED = sub { 1182our $DIED = sub {
721 warn "EV: error in callback (ignoring): $@"; 1183 warn "EV: error in callback (ignoring): $@";
722}; 1184};
723 1185
724default_loop 1186default_loop
725 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; 1187 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
726 1188
7271; 11891;
728 1190
729=head1 SEE ALSO 1191=head1 SEE ALSO
730 1192
731L<EV::DNS>. 1193L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
1194event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
1195coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1196event-loop agnostic and portable event driven programming.
732 1197
733=head1 AUTHOR 1198=head1 AUTHOR
734 1199
735 Marc Lehmann <schmorp@schmorp.de> 1200 Marc Lehmann <schmorp@schmorp.de>
736 http://home.schmorp.de/ 1201 http://home.schmorp.de/
737 1202
738=cut 1203=cut
739 1204

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