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Revision 1.63 by root, Fri Dec 7 18:11:21 2007 UTC vs.
Revision 1.136 by root, Thu Jan 19 17:55:23 2012 UTC

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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::run; # 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::run EV::RUN_ONCE; # 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::run EV::RUN_NOWAIT; # 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>, or just about in any case 72discussion on the available backends, or how to force a specific backend
64because it has much more detailed information. 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.
65 116
66=cut 117=cut
67 118
68package EV; 119package EV;
69 120
70use strict; 121use common::sense;
71 122
72BEGIN { 123BEGIN {
73 our $VERSION = '1.71'; 124 our $VERSION = '4.10';
74 use XSLoader; 125 use XSLoader;
75 XSLoader::load "EV", $VERSION; 126 XSLoader::load "EV", $VERSION;
76} 127}
77 128
78@EV::IO::ISA = 129@EV::IO::ISA =
… …
84@EV::Idle::ISA = 135@EV::Idle::ISA =
85@EV::Prepare::ISA = 136@EV::Prepare::ISA =
86@EV::Check::ISA = 137@EV::Check::ISA =
87@EV::Embed::ISA = 138@EV::Embed::ISA =
88@EV::Fork::ISA = 139@EV::Fork::ISA =
140@EV::Async::ISA =
89 "EV::Watcher"; 141 "EV::Watcher";
90 142
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->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
207
91=head1 BASIC INTERFACE 208=head1 BASIC INTERFACE
92 209
93=over 4 210=over 4
94 211
95=item $EV::DIED 212=item $EV::DIED
96 213
97Must 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
98throws an exception (with $@ containing thr error). The default prints an 215throws an exception (with $@ containing the error). The default prints an
99informative message and continues. 216informative message and continues.
100 217
101If this callback throws an exception it will be silently ignored. 218If this callback throws an exception it will be silently ignored.
102 219
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
103=item $time = EV::time 234=item $time = EV::time
104 235
105Returns the current time in (fractional) seconds since the epoch. 236Returns the current time in (fractional) seconds since the epoch.
106 237
107=item $time = EV::now 238=item $time = EV::now
108 239
240=item $time = $loop->now
241
109Returns the time the last event loop iteration has been started. This 242Returns the time the last event loop iteration has been started. This
110is 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
111usually faster then calling EV::time. 244usually faster then calling EV::time.
112 245
113=item $method = EV::method 246=item EV::now_update
114 247
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 = $loop->backend
291
115Returns an integer describing the backend used by libev (EV::METHOD_SELECT 292Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
116or EV::METHOD_EPOLL). 293or EV::BACKEND_EPOLL).
117 294
118=item EV::loop [$flags] 295=item EV::run [$flags]
296
297=item $loop->run ([$flags])
119 298
120Begin checking for events and calling callbacks. It returns when a 299Begin checking for events and calling callbacks. It returns when a
121callback calls EV::unloop. 300callback calls EV::unloop.
122 301
123The $flags argument can be one of the following: 302The $flags argument can be one of the following:
124 303
125 0 as above 304 0 as above
126 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 305 EV::RUN_ONCE block at most once (wait, but do not loop)
127 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 306 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
128 307
129=item EV::unloop [$how] 308=item EV::break [$how]
130 309
310=item $loop->break ([$how])
311
131When called with no arguments or an argument of EV::UNLOOP_ONE, makes the 312When called with no arguments or an argument of EV::BREAK_ONE, makes the
132innermost call to EV::loop return. 313innermost call to EV::loop return.
133 314
134When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as 315When called with an argument of EV::BREAK_ALL, all calls to EV::loop will
135fast as possible. 316return as fast as possible.
136 317
137=item $count = EV::loop_count 318When called with an argument of EV::BREAK_CANCEL, any pending break will
319be cancelled.
320
321=item $count = EV::iteration
322
323=item $count = $loop->iteration
138 324
139Return the number of times the event loop has polled for new 325Return the number of times the event loop has polled for new
140events. Sometiems useful as a generation counter. 326events. Sometimes useful as a generation counter.
141 327
142=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 328=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
329
330=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
143 331
144This function rolls together an I/O and a timer watcher for a single 332This function rolls together an I/O and a timer watcher for a single
145one-shot event without the need for managing a watcher object. 333one-shot event without the need for managing a watcher object.
146 334
147If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> 335If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
… …
153If timeout is C<undef> or negative, then there will be no 341If timeout is C<undef> or negative, then there will be no
154timeout. Otherwise a EV::timer with this value will be started. 342timeout. Otherwise a EV::timer with this value will be started.
155 343
156When an error occurs or either the timeout or I/O watcher triggers, then 344When an error occurs or either the timeout or I/O watcher triggers, then
157the callback will be called with the received event set (in general 345the callback will be called with the received event set (in general
158you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>, 346you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
159C<EV::WRITE> and C<EV::TIMEOUT>). 347C<EV::WRITE> and C<EV::TIMER>).
160 348
161EV::once doesn't return anything: the watchers stay active till either 349EV::once doesn't return anything: the watchers stay active till either
162of them triggers, then they will be stopped and freed, and the callback 350of them triggers, then they will be stopped and freed, and the callback
163invoked. 351invoked.
164 352
165=back 353=item EV::feed_fd_event $fd, $revents
166 354
355=item $loop->feed_fd_event ($fd, $revents)
356
357Feed an event on a file descriptor into EV. EV will react to this call as
358if the readyness notifications specified by C<$revents> (a combination of
359C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
360
361=item EV::feed_signal_event $signal
362
363Feed a signal event into the default loop. EV will react to this call as
364if the signal specified by C<$signal> had occured.
365
366=item EV::feed_signal $signal
367
368Feed a signal event into EV - unlike C<EV::feed_signal_event>, this works
369regardless of which loop has registered the signal, and is mainly useful
370fro custom signal implementations.
371
372=item EV::set_io_collect_interval $time
373
374=item $loop->set_io_collect_interval ($time)
375
376=item EV::set_timeout_collect_interval $time
377
378=item $loop->set_timeout_collect_interval ($time)
379
380These advanced functions set the minimum block interval when polling for I/O events and the minimum
381wait interval for timer events. See the libev documentation at
382L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
383(locally installed as F<EV::libev>) for a more detailed discussion.
384
385=item $count = EV::pending_count
386
387=item $count = $loop->pending_count
388
389Returns the number of currently pending watchers.
390
391=item EV::invoke_pending
392
393=item $loop->invoke_pending
394
395Invoke all currently pending watchers.
396
397=back
398
399
167=head2 WATCHER OBJECTS 400=head1 WATCHER OBJECTS
168 401
169A watcher is an object that gets created to record your interest in some 402A watcher is an object that gets created to record your interest in some
170event. For instance, if you want to wait for STDIN to become readable, you 403event. For instance, if you want to wait for STDIN to become readable, you
171would create an EV::io watcher for that: 404would create an EV::io watcher for that:
172 405
173 my $watcher = EV::io *STDIN, EV::READ, sub { 406 my $watcher = EV::io *STDIN, EV::READ, sub {
174 my ($watcher, $revents) = @_; 407 my ($watcher, $revents) = @_;
175 warn "yeah, STDIN should not be readable without blocking!\n" 408 warn "yeah, STDIN should now be readable without blocking!\n"
176 }; 409 };
177 410
178All watchers can be active (waiting for events) or inactive (paused). Only 411All watchers can be active (waiting for events) or inactive (paused). Only
179active watchers will have their callbacks invoked. All callbacks will be 412active watchers will have their callbacks invoked. All callbacks will be
180called with at least two arguments: the watcher and a bitmask of received 413called with at least two arguments: the watcher and a bitmask of received
181events. 414events.
182 415
183Each watcher type has its associated bit in revents, so you can use the 416Each watcher type has its associated bit in revents, so you can use the
184same callback for multiple watchers. The event mask is named after the 417same callback for multiple watchers. The event mask is named after the
185type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 418type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
186EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events 419EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
187(which can set both EV::READ and EV::WRITE bits), and EV::timer (which 420(which can set both EV::READ and EV::WRITE bits).
188uses EV::TIMEOUT).
189 421
190In the rare case where one wants to create a watcher but not start it at 422In the rare case where one wants to create a watcher but not start it at
191the same time, each constructor has a variant with a trailing C<_ns> in 423the same time, each constructor has a variant with a trailing C<_ns> in
192its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. 424its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
193 425
… …
253The default priority of any newly-created watcher is 0. 485The default priority of any newly-created watcher is 0.
254 486
255Note that the priority semantics have not yet been fleshed out and are 487Note that the priority semantics have not yet been fleshed out and are
256subject to almost certain change. 488subject to almost certain change.
257 489
258=item $w->trigger ($revents) 490=item $w->invoke ($revents)
259 491
260Call the callback *now* with the given event mask. 492Call the callback *now* with the given event mask.
493
494=item $w->feed_event ($revents)
495
496Feed some events on this watcher into EV. EV will react to this call as if
497the watcher had received the given C<$revents> mask.
498
499=item $revents = $w->clear_pending
500
501If the watcher is pending, this function clears its pending status and
502returns its C<$revents> bitset (as if its callback was invoked). If the
503watcher isn't pending it does nothing and returns C<0>.
261 504
262=item $previous_state = $w->keepalive ($bool) 505=item $previous_state = $w->keepalive ($bool)
263 506
264Normally, C<EV::loop> will return when there are no active watchers 507Normally, C<EV::loop> will return when there are no active watchers
265(which is a "deadlock" because no progress can be made anymore). This is 508(which is a "deadlock" because no progress can be made anymore). This is
266convinient because it allows you to start your watchers (and your jobs), 509convenient because it allows you to start your watchers (and your jobs),
267call C<EV::loop> once and when it returns you know that all your jobs are 510call C<EV::loop> once and when it returns you know that all your jobs are
268finished (or they forgot to register some watchers for their task :). 511finished (or they forgot to register some watchers for their task :).
269 512
270Sometimes, however, this gets in your way, for example when you the module 513Sometimes, however, this gets in your way, for example when the module
271that calls C<EV::loop> (usually the main program) is not the same module 514that calls C<EV::loop> (usually the main program) is not the same module
272as a long-living watcher (for example a DNS client module written by 515as a long-living watcher (for example a DNS client module written by
273somebody else even). Then you might want any outstanding requests to be 516somebody else even). Then you might want any outstanding requests to be
274handled, but you would not want to keep C<EV::loop> from returning just 517handled, but you would not want to keep C<EV::loop> from returning just
275because you happen to have this long-running UDP port watcher. 518because you happen to have this long-running UDP port watcher.
276 519
277In this case you can clear the keepalive status, which means that even 520In this case you can clear the keepalive status, which means that even
278though your watcher is active, it won't keep C<EV::loop> from returning. 521though your watcher is active, it won't keep C<EV::loop> from returning.
279 522
280The initial value for keepalive is true (enabled), and you cna change it 523The initial value for keepalive is true (enabled), and you can change it
281any time. 524any time.
282 525
283Example: Register an I/O watcher for some UDP socket but do not keep the 526Example: Register an I/O watcher for some UDP socket but do not keep the
284event loop from running just because of that watcher. 527event loop from running just because of that watcher.
285 528
286 my $udp_socket = ... 529 my $udp_socket = ...
287 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 530 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
288 $udp_watcher->keepalive (0); 531 $udp_watcher->keepalive (0);
289 532
290=back 533=item $loop = $w->loop
291 534
535Return the loop that this watcher is attached to.
292 536
537=back
538
539
293=head2 WATCHER TYPES 540=head1 WATCHER TYPES
294 541
295Each of the following subsections describes a single watcher type. 542Each of the following subsections describes a single watcher type.
296 543
297=head3 I/O WATCHERS - is this file descriptor readable or writable? 544=head3 I/O WATCHERS - is this file descriptor readable or writable?
298 545
299=over 4 546=over 4
300 547
301=item $w = EV::io $fileno_or_fh, $eventmask, $callback 548=item $w = EV::io $fileno_or_fh, $eventmask, $callback
302 549
303=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 550=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
551
552=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
553
554=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
304 555
305As long as the returned watcher object is alive, call the C<$callback> 556As long as the returned watcher object is alive, call the C<$callback>
306when at least one of events specified in C<$eventmask> occurs. 557when at least one of events specified in C<$eventmask> occurs.
307 558
308The $eventmask can be one or more of these constants ORed together: 559The $eventmask can be one or more of these constants ORed together:
… …
337=over 4 588=over 4
338 589
339=item $w = EV::timer $after, $repeat, $callback 590=item $w = EV::timer $after, $repeat, $callback
340 591
341=item $w = EV::timer_ns $after, $repeat, $callback 592=item $w = EV::timer_ns $after, $repeat, $callback
593
594=item $w = $loop->timer ($after, $repeat, $callback)
595
596=item $w = $loop->timer_ns ($after, $repeat, $callback)
342 597
343Calls the callback after C<$after> seconds (which may be fractional). If 598Calls the callback after C<$after> seconds (which may be fractional). If
344C<$repeat> is non-zero, the timer will be restarted (with the $repeat 599C<$repeat> is non-zero, the timer will be restarted (with the $repeat
345value as $after) after the callback returns. 600value as $after) after the callback returns.
346 601
… …
387=over 4 642=over 4
388 643
389=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback 644=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
390 645
391=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 646=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
647
648=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
649
650=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
392 651
393Similar to EV::timer, but is not based on relative timeouts but on 652Similar to EV::timer, but is not based on relative timeouts but on
394absolute times. Apart from creating "simple" timers that trigger "at" the 653absolute times. Apart from creating "simple" timers that trigger "at" the
395specified time, it can also be used for non-drifting absolute timers and 654specified time, it can also be used for non-drifting absolute timers and
396more complex, cron-like, setups that are not adversely affected by time 655more complex, cron-like, setups that are not adversely affected by time
… …
406This time simply fires at the wallclock time C<$at> and doesn't repeat. It 665This time simply fires at the wallclock time C<$at> and doesn't repeat. It
407will not adjust when a time jump occurs, that is, if it is to be run 666will not adjust when a time jump occurs, that is, if it is to be run
408at January 1st 2011 then it will run when the system time reaches or 667at January 1st 2011 then it will run when the system time reaches or
409surpasses this time. 668surpasses this time.
410 669
411=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 670=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
412 671
413In this mode the watcher will always be scheduled to time out at the 672In this mode the watcher will always be scheduled to time out at the
414next C<$at + N * $interval> time (for some integer N) and then repeat, 673next C<$at + N * $interval> time (for some integer N) and then repeat,
415regardless of any time jumps. 674regardless of any time jumps.
416 675
… …
434time the periodic watcher gets scheduled, the reschedule callback 693time the periodic watcher gets scheduled, the reschedule callback
435($reschedule_cb) will be called with the watcher as first, and the current 694($reschedule_cb) will be called with the watcher as first, and the current
436time as second argument. 695time as second argument.
437 696
438I<This callback MUST NOT stop or destroy this or any other periodic 697I<This callback MUST NOT stop or destroy this or any other periodic
439watcher, ever>. If you need to stop it, return 1e30 and stop it 698watcher, ever, and MUST NOT call any event loop functions or methods>. If
440afterwards. 699you need to stop it, return 1e30 and stop it afterwards. You may create
700and start a C<EV::prepare> watcher for this task.
441 701
442It must return the next time to trigger, based on the passed time value 702It must return the next time to trigger, based on the passed time value
443(that is, the lowest time value larger than to the second argument). It 703(that is, the lowest time value larger than or equal to to the second
444will usually be called just before the callback will be triggered, but 704argument). It will usually be called just before the callback will be
445might be called at other times, too. 705triggered, but might be called at other times, too.
446 706
447This can be used to create very complex timers, such as a timer that 707This can be used to create very complex timers, such as a timer that
448triggers on each midnight, local time (actually 24 hours after the last 708triggers on each midnight, local time (actually 24 hours after the last
449midnight, to keep the example simple. If you know a way to do it correctly 709midnight, to keep the example simple. If you know a way to do it correctly
450in about the same space (without requiring elaborate modules), drop me a 710in about the same space (without requiring elaborate modules), drop me a
… …
471 731
472=item $w->again 732=item $w->again
473 733
474Simply stops and starts the watcher again. 734Simply stops and starts the watcher again.
475 735
736=item $time = $w->at
737
738Return the time that the watcher is expected to trigger next.
739
476=back 740=back
477 741
478 742
479=head3 SIGNAL WATCHERS - signal me when a signal gets signalled! 743=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
480 744
481=over 4 745=over 4
482 746
483=item $w = EV::signal $signal, $callback 747=item $w = EV::signal $signal, $callback
484 748
485=item $w = EV::signal_ns $signal, $callback 749=item $w = EV::signal_ns $signal, $callback
750
751=item $w = $loop->signal ($signal, $callback)
752
753=item $w = $loop->signal_ns ($signal, $callback)
486 754
487Call the callback when $signal is received (the signal can be specified by 755Call the callback when $signal is received (the signal can be specified by
488number or by name, just as with C<kill> or C<%SIG>). 756number or by name, just as with C<kill> or C<%SIG>).
757
758Only one event loop can grab a given signal - attempting to grab the same
759signal from two EV loops will crash the program immediately or cause data
760corruption.
489 761
490EV will grab the signal for the process (the kernel only allows one 762EV will grab the signal for the process (the kernel only allows one
491component to receive a signal at a time) when you start a signal watcher, 763component to receive a signal at a time) when you start a signal watcher,
492and removes it again when you stop it. Perl does the same when you 764and removes it again when you stop it. Perl does the same when you
493add/remove callbacks to C<%SIG>, so watch out. 765add/remove callbacks to C<%SIG>, so watch out.
… …
513 785
514=head3 CHILD WATCHERS - watch out for process status changes 786=head3 CHILD WATCHERS - watch out for process status changes
515 787
516=over 4 788=over 4
517 789
518=item $w = EV::child $pid, $callback 790=item $w = EV::child $pid, $trace, $callback
519 791
520=item $w = EV::child_ns $pid, $callback 792=item $w = EV::child_ns $pid, $trace, $callback
521 793
794=item $w = $loop->child ($pid, $trace, $callback)
795
796=item $w = $loop->child_ns ($pid, $trace, $callback)
797
522Call the callback when a status change for pid C<$pid> (or any pid if 798Call the callback when a status change for pid C<$pid> (or any pid
523C<$pid> is 0) has been received. More precisely: when the process receives 799if C<$pid> is 0) has been received (a status change happens when the
800process terminates or is killed, or, when trace is true, additionally when
801it is stopped or continued). More precisely: when the process receives
524a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all 802a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
525changed/zombie children and call the callback. 803changed/zombie children and call the callback.
526 804
527It is valid (and fully supported) to install a child watcher after a child 805It is valid (and fully supported) to install a child watcher after a child
528has exited but before the event loop has started its next iteration (for 806has exited but before the event loop has started its next iteration (for
… …
535You can have as many pid watchers per pid as you want, they will all be 813You can have as many pid watchers per pid as you want, they will all be
536called. 814called.
537 815
538The C<child_ns> variant doesn't start (activate) the newly created watcher. 816The C<child_ns> variant doesn't start (activate) the newly created watcher.
539 817
540=item $w->set ($pid) 818=item $w->set ($pid, $trace)
541 819
542Reconfigures the watcher, see the constructor above for details. Can be called at 820Reconfigures the watcher, see the constructor above for details. Can be called at
543any time. 821any time.
544 822
545=item $current_pid = $w->pid 823=item $current_pid = $w->pid
546 824
547=item $old_pid = $w->pid ($new_pid)
548
549Returns the previously set process id and optionally set a new one. 825Returns the previously set process id and optionally set a new one.
550 826
551=item $exit_status = $w->rstatus 827=item $exit_status = $w->rstatus
552 828
553Return the exit/wait status (as returned by waitpid, see the waitpid entry 829Return the exit/wait status (as returned by waitpid, see the waitpid entry
… …
566=over 4 842=over 4
567 843
568=item $w = EV::stat $path, $interval, $callback 844=item $w = EV::stat $path, $interval, $callback
569 845
570=item $w = EV::stat_ns $path, $interval, $callback 846=item $w = EV::stat_ns $path, $interval, $callback
847
848=item $w = $loop->stat ($path, $interval, $callback)
849
850=item $w = $loop->stat_ns ($path, $interval, $callback)
571 851
572Call the callback when a file status change has been detected on 852Call the callback when a file status change has been detected on
573C<$path>. The C<$path> does not need to exist, changing from "path exists" 853C<$path>. The C<$path> does not need to exist, changing from "path exists"
574to "path does not exist" is a status change like any other. 854to "path does not exist" is a status change like any other.
575 855
… …
645=over 4 925=over 4
646 926
647=item $w = EV::idle $callback 927=item $w = EV::idle $callback
648 928
649=item $w = EV::idle_ns $callback 929=item $w = EV::idle_ns $callback
930
931=item $w = $loop->idle ($callback)
932
933=item $w = $loop->idle_ns ($callback)
650 934
651Call the callback when there are no other pending watchers of the same or 935Call the callback when there are no other pending watchers of the same or
652higher priority (excluding check, prepare and other idle watchers of the 936higher priority (excluding check, prepare and other idle watchers of the
653same or lower priority, of course). They are called idle watchers because 937same or lower priority, of course). They are called idle watchers because
654when the watcher is the highest priority pending event in the process, the 938when the watcher is the highest priority pending event in the process, the
… …
677 961
678=item $w = EV::prepare $callback 962=item $w = EV::prepare $callback
679 963
680=item $w = EV::prepare_ns $callback 964=item $w = EV::prepare_ns $callback
681 965
966=item $w = $loop->prepare ($callback)
967
968=item $w = $loop->prepare_ns ($callback)
969
682Call the callback just before the process would block. You can still 970Call the callback just before the process would block. You can still
683create/modify any watchers at this point. 971create/modify any watchers at this point.
684 972
685See the EV::check watcher, below, for explanations and an example. 973See the EV::check watcher, below, for explanations and an example.
686 974
… …
695 983
696=item $w = EV::check $callback 984=item $w = EV::check $callback
697 985
698=item $w = EV::check_ns $callback 986=item $w = EV::check_ns $callback
699 987
988=item $w = $loop->check ($callback)
989
990=item $w = $loop->check_ns ($callback)
991
700Call the callback just after the process wakes up again (after it has 992Call the callback just after the process wakes up again (after it has
701gathered events), but before any other callbacks have been invoked. 993gathered events), but before any other callbacks have been invoked.
702 994
703This is used to integrate other event-based software into the EV 995This can be used to integrate other event-based software into the EV
704mainloop: You register a prepare callback and in there, you create io and 996mainloop: You register a prepare callback and in there, you create io and
705timer watchers as required by the other software. Here is a real-world 997timer watchers as required by the other software. Here is a real-world
706example of integrating Net::SNMP (with some details left out): 998example of integrating Net::SNMP (with some details left out):
707 999
708 our @snmp_watcher; 1000 our @snmp_watcher;
… …
738 # make the dispatcher handle any new stuff 1030 # make the dispatcher handle any new stuff
739 ... not shown 1031 ... not shown
740 }; 1032 };
741 1033
742The callbacks of the created watchers will not be called as the watchers 1034The callbacks of the created watchers will not be called as the watchers
743are destroyed before this cna happen (remember EV::check gets called 1035are destroyed before this can happen (remember EV::check gets called
744first). 1036first).
745 1037
746The C<check_ns> variant doesn't start (activate) the newly created watcher. 1038The C<check_ns> variant doesn't start (activate) the newly created watcher.
1039
1040=item EV::CHECK constant issues
1041
1042Like all other watcher types, there is a bitmask constant for use in
1043C<$revents> and other places. The C<EV::CHECK> is special as it has
1044the same name as the C<CHECK> sub called by Perl. This doesn't cause
1045big issues on newer perls (beginning with 5.8.9), but it means thatthe
1046constant must be I<inlined>, i.e. runtime calls will not work. That means
1047that as long as you always C<use EV> and then C<EV::CHECK> you are on the
1048safe side.
747 1049
748=back 1050=back
749 1051
750 1052
751=head3 FORK WATCHERS - the audacity to resume the event loop after a fork 1053=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
… …
758 1060
759=item $w = EV::fork $callback 1061=item $w = EV::fork $callback
760 1062
761=item $w = EV::fork_ns $callback 1063=item $w = EV::fork_ns $callback
762 1064
1065=item $w = $loop->fork ($callback)
1066
1067=item $w = $loop->fork_ns ($callback)
1068
763Call the callback before the event loop is resumed in the child process 1069Call the callback before the event loop is resumed in the child process
764after a fork. 1070after a fork.
765 1071
766The C<fork_ns> variant doesn't start (activate) the newly created watcher. 1072The C<fork_ns> variant doesn't start (activate) the newly created watcher.
1073
1074=back
1075
1076
1077=head3 EMBED WATCHERS - when one backend isn't enough...
1078
1079This is a rather advanced watcher type that lets you embed one event loop
1080into another (currently only IO events are supported in the embedded
1081loop, other types of watchers might be handled in a delayed or incorrect
1082fashion and must not be used).
1083
1084See the libev documentation at
1085L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
1086(locally installed as F<EV::libev>) for more details.
1087
1088In short, this watcher is most useful on BSD systems without working
1089kqueue to still be able to handle a large number of sockets:
1090
1091 my $socket_loop;
1092
1093 # check wether we use SELECT or POLL _and_ KQUEUE is supported
1094 if (
1095 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
1096 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
1097 ) {
1098 # use kqueue for sockets
1099 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
1100 }
1101
1102 # use the default loop otherwise
1103 $socket_loop ||= EV::default_loop;
1104
1105=over 4
1106
1107=item $w = EV::embed $otherloop[, $callback]
1108
1109=item $w = EV::embed_ns $otherloop[, $callback]
1110
1111=item $w = $loop->embed ($otherloop[, $callback])
1112
1113=item $w = $loop->embed_ns ($otherloop[, $callback])
1114
1115Call the callback when the embedded event loop (C<$otherloop>) has any
1116I/O activity. The C<$callback> is optional: if it is missing, then the
1117embedded event loop will be managed automatically (which is recommended),
1118otherwise you have to invoke C<sweep> yourself.
1119
1120The C<embed_ns> variant doesn't start (activate) the newly created watcher.
1121
1122=back
1123
1124=head3 ASYNC WATCHERS - how to wake up another event loop
1125
1126Async watchers are provided by EV, but have little use in perl directly,
1127as perl neither supports threads running in parallel nor direct access to
1128signal handlers or other contexts where they could be of value.
1129
1130It is, however, possible to use them from the XS level.
1131
1132Please see the libev documentation for further details.
1133
1134=over 4
1135
1136=item $w = EV::async $callback
1137
1138=item $w = EV::async_ns $callback
1139
1140=item $w->send
1141
1142=item $bool = $w->async_pending
767 1143
768=back 1144=back
769 1145
770 1146
771=head1 PERL SIGNALS 1147=head1 PERL SIGNALS
… …
782to be called on every event loop iteration by installing a C<EV::check> 1158to be called on every event loop iteration by installing a C<EV::check>
783watcher: 1159watcher:
784 1160
785 my $async_check = EV::check sub { }; 1161 my $async_check = EV::check sub { };
786 1162
787This ensures that perl shortly gets into control for a short time, and 1163This ensures that perl gets into control for a short time to handle any
788also ensures slower overall operation. 1164pending signals, and also ensures (slightly) slower overall operation.
789 1165
790=head1 THREADS 1166=head1 ITHREADS
791 1167
792Threads are not supported by this module in any way. Perl pseudo-threads 1168Ithreads are not supported by this module in any way. Perl pseudo-threads
793is evil stuff and must die. As soon as Perl gains real threads I will work 1169is evil stuff and must die. Real threads as provided by Coro are fully
794on thread support for it. 1170supported (and enhanced support is available via L<Coro::EV>).
795 1171
796=head1 FORK 1172=head1 FORK
797 1173
798Most of the "improved" event delivering mechanisms of modern operating 1174Most of the "improved" event delivering mechanisms of modern operating
799systems have quite a few problems with fork(2) (to put it bluntly: it is 1175systems have quite a few problems with fork(2) (to put it bluntly: it is
… …
815our $DIED = sub { 1191our $DIED = sub {
816 warn "EV: error in callback (ignoring): $@"; 1192 warn "EV: error in callback (ignoring): $@";
817}; 1193};
818 1194
819default_loop 1195default_loop
820 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; 1196 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
821 1197
8221; 11981;
823 1199
824=head1 SEE ALSO 1200=head1 SEE ALSO
825 1201
1202L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS>
826L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as 1203(asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as event
827event loop), L<Coro::EV> (efficient coroutines with EV). 1204loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient thread
1205integration), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1206event-loop agnostic and portable event driven programming.
828 1207
829=head1 AUTHOR 1208=head1 AUTHOR
830 1209
831 Marc Lehmann <schmorp@schmorp.de> 1210 Marc Lehmann <schmorp@schmorp.de>
832 http://home.schmorp.de/ 1211 http://home.schmorp.de/
833 1212
834=cut 1213=cut
835 1214

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