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Revision 1.64 by root, Sat Dec 8 02:55:13 2007 UTC vs.
Revision 1.131 by root, Sun Dec 5 11:45:22 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>, 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 = '1.8'; 124 our $VERSION = '4.01';
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->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::loop [$flags]
296
297=item $loop->loop ([$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 $flags argument can be one of the following:
… …
126 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 305 EV::LOOP_ONESHOT block at most once (wait, but do not loop)
127 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 306 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
128 307
129=item EV::unloop [$how] 308=item EV::unloop [$how]
130 309
310=item $loop->unloop ([$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::UNLOOP_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::UNLOOP_ALL, all calls to EV::loop will return as
135fast as possible. 316fast as possible.
136 317
137=item $count = EV::loop_count 318=item $count = EV::loop_count
138 319
320=item $count = $loop->loop_count
321
139Return the number of times the event loop has polled for new 322Return the number of times the event loop has polled for new
140events. Sometiems useful as a generation counter. 323events. Sometimes useful as a generation counter.
141 324
142=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))
143 328
144This 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
145one-shot event without the need for managing a watcher object. 330one-shot event without the need for managing a watcher object.
146 331
147If 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>
… …
153If timeout is C<undef> or negative, then there will be no 338If timeout is C<undef> or negative, then there will be no
154timeout. Otherwise a EV::timer with this value will be started. 339timeout. Otherwise a EV::timer with this value will be started.
155 340
156When 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
157the callback will be called with the received event set (in general 342the 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>, 343you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
159C<EV::WRITE> and C<EV::TIMEOUT>). 344C<EV::WRITE> and C<EV::TIMER>).
160 345
161EV::once doesn't return anything: the watchers stay active till either 346EV::once doesn't return anything: the watchers stay active till either
162of 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
163invoked. 348invoked.
164 349
165=back 350=item EV::feed_fd_event ($fd, $revents)
166 351
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
167=head2 WATCHER OBJECTS 391=head1 WATCHER OBJECTS
168 392
169A 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
170event. 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
171would create an EV::io watcher for that: 395would create an EV::io watcher for that:
172 396
173 my $watcher = EV::io *STDIN, EV::READ, sub { 397 my $watcher = EV::io *STDIN, EV::READ, sub {
174 my ($watcher, $revents) = @_; 398 my ($watcher, $revents) = @_;
175 warn "yeah, STDIN should not be readable without blocking!\n" 399 warn "yeah, STDIN should now be readable without blocking!\n"
176 }; 400 };
177 401
178All watchers can be active (waiting for events) or inactive (paused). Only 402All watchers can be active (waiting for events) or inactive (paused). Only
179active watchers will have their callbacks invoked. All callbacks will be 403active watchers will have their callbacks invoked. All callbacks will be
180called 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
181events. 405events.
182 406
183Each 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
184same callback for multiple watchers. The event mask is named after the 408same callback for multiple watchers. The event mask is named after the
185type, 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,
186EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events 410EV::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 411(which can set both EV::READ and EV::WRITE bits).
188uses EV::TIMEOUT).
189 412
190In 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
191the 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
192its 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.
193 416
… …
253The default priority of any newly-created watcher is 0. 476The default priority of any newly-created watcher is 0.
254 477
255Note 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
256subject to almost certain change. 479subject to almost certain change.
257 480
258=item $w->trigger ($revents) 481=item $w->invoke ($revents)
259 482
260Call 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>.
261 495
262=item $previous_state = $w->keepalive ($bool) 496=item $previous_state = $w->keepalive ($bool)
263 497
264Normally, C<EV::loop> will return when there are no active watchers 498Normally, 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 499(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), 500convenient 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 501call 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 :). 502finished (or they forgot to register some watchers for their task :).
269 503
270Sometimes, however, this gets in your way, for example when you the module 504Sometimes, 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 505that 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 506as a long-living watcher (for example a DNS client module written by
273somebody else even). Then you might want any outstanding requests to be 507somebody 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 508handled, but you would not want to keep C<EV::loop> from returning just
275because you happen to have this long-running UDP port watcher. 509because you happen to have this long-running UDP port watcher.
276 510
277In 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
278though 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.
279 513
280The 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
281any time. 515any time.
282 516
283Example: Register an I/O 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
284event loop from running just because of that watcher. 518event loop from running just because of that watcher.
285 519
286 my $udp_socket = ... 520 my $udp_socket = ...
287 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 521 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
288 $udp_watcher->keepalive (0); 522 $udp_watcher->keepalive (0);
289 523
290=back 524=item $loop = $w->loop
291 525
526Return the loop that this watcher is attached to.
292 527
528=back
529
530
293=head2 WATCHER TYPES 531=head1 WATCHER TYPES
294 532
295Each of the following subsections describes a single watcher type. 533Each of the following subsections describes a single watcher type.
296 534
297=head3 I/O WATCHERS - is this file descriptor readable or writable? 535=head3 I/O WATCHERS - is this file descriptor readable or writable?
298 536
299=over 4 537=over 4
300 538
301=item $w = EV::io $fileno_or_fh, $eventmask, $callback 539=item $w = EV::io $fileno_or_fh, $eventmask, $callback
302 540
303=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, $callback)
304 546
305As long as the returned watcher object is alive, call the C<$callback> 547As long as the returned watcher object is alive, call the C<$callback>
306when at least one of events specified in C<$eventmask> occurs. 548when at least one of events specified in C<$eventmask> occurs.
307 549
308The $eventmask can be one or more of these constants ORed together: 550The $eventmask can be one or more of these constants ORed together:
… …
337=over 4 579=over 4
338 580
339=item $w = EV::timer $after, $repeat, $callback 581=item $w = EV::timer $after, $repeat, $callback
340 582
341=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, $callback)
342 588
343Calls the callback after C<$after> seconds (which may be fractional). If 589Calls the callback after C<$after> seconds (which may be fractional). If
344C<$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
345value as $after) after the callback returns. 591value as $after) after the callback returns.
346 592
… …
387=over 4 633=over 4
388 634
389=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback 635=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
390 636
391=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, $callback)
392 642
393Similar to EV::timer, but is not based on relative timeouts but on 643Similar to EV::timer, but is not based on relative timeouts but on
394absolute times. Apart from creating "simple" timers that trigger "at" the 644absolute times. Apart from creating "simple" timers that trigger "at" the
395specified time, it can also be used for non-drifting absolute timers and 645specified time, it can also be used for non-drifting absolute timers and
396more complex, cron-like, setups that are not adversely affected by time 646more complex, cron-like, setups that are not adversely affected by time
… …
406This time simply fires at the wallclock time C<$at> and doesn't repeat. It 656This time simply fires at the wallclock time C<$at> and doesn't repeat. It
407will not adjust when a time jump occurs, that is, if it is to be run 657will not adjust when a time jump occurs, that is, if it is to be run
408at January 1st 2011 then it will run when the system time reaches or 658at January 1st 2011 then it will run when the system time reaches or
409surpasses this time. 659surpasses this time.
410 660
411=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 661=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
412 662
413In this mode the watcher will always be scheduled to time out at the 663In this mode the watcher will always be scheduled to time out at the
414next C<$at + N * $interval> time (for some integer N) and then repeat, 664next C<$at + N * $interval> time (for some integer N) and then repeat,
415regardless of any time jumps. 665regardless of any time jumps.
416 666
… …
434time the periodic watcher gets scheduled, the reschedule callback 684time the periodic watcher gets scheduled, the reschedule callback
435($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
436time as second argument. 686time as second argument.
437 687
438I<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
439watcher, 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
440afterwards. 690you need to stop it, return 1e30 and stop it afterwards. You may create
691and start a C<EV::prepare> watcher for this task.
441 692
442It 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
443(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
444will usually be called just before the callback will be triggered, but 695argument). It will usually be called just before the callback will be
445might be called at other times, too. 696triggered, but might be called at other times, too.
446 697
447This 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
448triggers on each midnight, local time (actually 24 hours after the last 699triggers 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 700midnight, 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 701in about the same space (without requiring elaborate modules), drop me a
… …
471 722
472=item $w->again 723=item $w->again
473 724
474Simply stops and starts the watcher again. 725Simply stops and starts the watcher again.
475 726
727=item $time = $w->at
728
729Return the time that the watcher is expected to trigger next.
730
476=back 731=back
477 732
478 733
479=head3 SIGNAL WATCHERS - signal me when a signal gets signalled! 734=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
480 735
481=over 4 736=over 4
482 737
483=item $w = EV::signal $signal, $callback 738=item $w = EV::signal $signal, $callback
484 739
485=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)
486 745
487Call 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
488number 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.
489 752
490EV 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
491component 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,
492and 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
493add/remove callbacks to C<%SIG>, so watch out. 756add/remove callbacks to C<%SIG>, so watch out.
… …
513 776
514=head3 CHILD WATCHERS - watch out for process status changes 777=head3 CHILD WATCHERS - watch out for process status changes
515 778
516=over 4 779=over 4
517 780
518=item $w = EV::child $pid, $callback 781=item $w = EV::child $pid, $trace, $callback
519 782
520=item $w = EV::child_ns $pid, $callback 783=item $w = EV::child_ns $pid, $trace, $callback
521 784
785=item $w = $loop->child ($pid, $trace, $callback)
786
787=item $w = $loop->child_ns ($pid, $trace, $callback)
788
522Call the callback when a status change for pid C<$pid> (or any pid if 789Call the callback when a status change for pid C<$pid> (or any pid
523C<$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
524a 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
525changed/zombie children and call the callback. 794changed/zombie children and call the callback.
526 795
527It 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
528has 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
… …
535You 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
536called. 805called.
537 806
538The 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.
539 808
540=item $w->set ($pid) 809=item $w->set ($pid, $trace)
541 810
542Reconfigures 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
543any time. 812any time.
544 813
545=item $current_pid = $w->pid 814=item $current_pid = $w->pid
546 815
547=item $old_pid = $w->pid ($new_pid)
548
549Returns the previously set process id and optionally set a new one. 816Returns the previously set process id and optionally set a new one.
550 817
551=item $exit_status = $w->rstatus 818=item $exit_status = $w->rstatus
552 819
553Return 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
… …
566=over 4 833=over 4
567 834
568=item $w = EV::stat $path, $interval, $callback 835=item $w = EV::stat $path, $interval, $callback
569 836
570=item $w = EV::stat_ns $path, $interval, $callback 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, $callback)
571 842
572Call the callback when a file status change has been detected on 843Call the callback when a file status change has been detected on
573C<$path>. The C<$path> does not need to exist, changing from "path exists" 844C<$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. 845to "path does not exist" is a status change like any other.
575 846
… …
645=over 4 916=over 4
646 917
647=item $w = EV::idle $callback 918=item $w = EV::idle $callback
648 919
649=item $w = EV::idle_ns $callback 920=item $w = EV::idle_ns $callback
921
922=item $w = $loop->idle ($callback)
923
924=item $w = $loop->idle_ns ($callback)
650 925
651Call the callback when there are no other pending watchers of the same or 926Call the callback when there are no other pending watchers of the same or
652higher priority (excluding check, prepare and other idle watchers of the 927higher priority (excluding check, prepare and other idle watchers of the
653same or lower priority, of course). They are called idle watchers because 928same or lower priority, of course). They are called idle watchers because
654when the watcher is the highest priority pending event in the process, the 929when the watcher is the highest priority pending event in the process, the
… …
677 952
678=item $w = EV::prepare $callback 953=item $w = EV::prepare $callback
679 954
680=item $w = EV::prepare_ns $callback 955=item $w = EV::prepare_ns $callback
681 956
957=item $w = $loop->prepare ($callback)
958
959=item $w = $loop->prepare_ns ($callback)
960
682Call the callback just before the process would block. You can still 961Call the callback just before the process would block. You can still
683create/modify any watchers at this point. 962create/modify any watchers at this point.
684 963
685See the EV::check watcher, below, for explanations and an example. 964See the EV::check watcher, below, for explanations and an example.
686 965
… …
695 974
696=item $w = EV::check $callback 975=item $w = EV::check $callback
697 976
698=item $w = EV::check_ns $callback 977=item $w = EV::check_ns $callback
699 978
979=item $w = $loop->check ($callback)
980
981=item $w = $loop->check_ns ($callback)
982
700Call 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
701gathered events), but before any other callbacks have been invoked. 984gathered events), but before any other callbacks have been invoked.
702 985
703This is used to integrate other event-based software into the EV 986This 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 987mainloop: 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 988timer watchers as required by the other software. Here is a real-world
706example of integrating Net::SNMP (with some details left out): 989example of integrating Net::SNMP (with some details left out):
707 990
708 our @snmp_watcher; 991 our @snmp_watcher;
… …
738 # make the dispatcher handle any new stuff 1021 # make the dispatcher handle any new stuff
739 ... not shown 1022 ... not shown
740 }; 1023 };
741 1024
742The 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
743are destroyed before this cna happen (remember EV::check gets called 1026are destroyed before this can happen (remember EV::check gets called
744first). 1027first).
745 1028
746The 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.
1030
1031=item EV::CHECK constant issues
1032
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.
747 1040
748=back 1041=back
749 1042
750 1043
751=head3 FORK WATCHERS - the audacity to resume the event loop after a fork 1044=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
… …
758 1051
759=item $w = EV::fork $callback 1052=item $w = EV::fork $callback
760 1053
761=item $w = EV::fork_ns $callback 1054=item $w = EV::fork_ns $callback
762 1055
1056=item $w = $loop->fork ($callback)
1057
1058=item $w = $loop->fork_ns ($callback)
1059
763Call the callback before the event loop is resumed in the child process 1060Call the callback before the event loop is resumed in the child process
764after a fork. 1061after a fork.
765 1062
766The C<fork_ns> variant doesn't start (activate) the newly created watcher. 1063The C<fork_ns> variant doesn't start (activate) the newly created watcher.
1064
1065=back
1066
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
767 1134
768=back 1135=back
769 1136
770 1137
771=head1 PERL SIGNALS 1138=head1 PERL SIGNALS
… …
782to be called on every event loop iteration by installing a C<EV::check> 1149to be called on every event loop iteration by installing a C<EV::check>
783watcher: 1150watcher:
784 1151
785 my $async_check = EV::check sub { }; 1152 my $async_check = EV::check sub { };
786 1153
787This ensures that perl shortly gets into control for a short time, and 1154This ensures that perl gets into control for a short time to handle any
788also ensures slower overall operation. 1155pending signals, and also ensures (slightly) slower overall operation.
789 1156
790=head1 THREADS 1157=head1 ITHREADS
791 1158
792Threads 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
793is 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
794on thread support for it. 1161supported (and enhanced support is available via L<Coro::EV>).
795 1162
796=head1 FORK 1163=head1 FORK
797 1164
798Most of the "improved" event delivering mechanisms of modern operating 1165Most of the "improved" event delivering mechanisms of modern operating
799systems 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
… …
815our $DIED = sub { 1182our $DIED = sub {
816 warn "EV: error in callback (ignoring): $@"; 1183 warn "EV: error in callback (ignoring): $@";
817}; 1184};
818 1185
819default_loop 1186default_loop
820 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; 1187 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
821 1188
8221; 11891;
823 1190
824=head1 SEE ALSO 1191=head1 SEE ALSO
825 1192
1193L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS>
826L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as 1194(asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as event
827event loop), L<Coro::EV> (efficient coroutines with EV). 1195loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient thread
1196integration), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1197event-loop agnostic and portable event driven programming.
828 1198
829=head1 AUTHOR 1199=head1 AUTHOR
830 1200
831 Marc Lehmann <schmorp@schmorp.de> 1201 Marc Lehmann <schmorp@schmorp.de>
832 http://home.schmorp.de/ 1202 http://home.schmorp.de/
833 1203
834=cut 1204=cut
835 1205

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