ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/EV/EV.pm
(Generate patch)

Comparing EV/EV.pm (file contents):
Revision 1.53 by root, Sat Nov 24 16:57:30 2007 UTC vs.
Revision 1.115 by root, Tue Apr 28 00:50:56 2009 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 { 45 # STAT CHANGES
12 warn "is called after 2s"; 46 my $w = EV::stat "/etc/passwd", 10, sub {
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, $revents) = @_; 47 my ($w, $revents) = @_;
42 my $status = $w->rstatus; 48 warn $w->path, " has changed somehow.\n";
43 }; 49 };
44 50
45 # MAINLOOP 51 # MAINLOOP
46 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
47 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
48 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
49 55
50=head1 DESCRIPTION 56=head1 DESCRIPTION
51 57
52This module provides an interface to libev 58This module provides an interface to libev
53(L<http://software.schmorp.de/pkg/libev.html>). While the documentation 59(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
54below is comprehensive, one might also consult the documentation of libev 60below is comprehensive, one might also consult the documentation of
55itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on 61libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
56watcher semantics or some discussion on the available backends, or how to 62F<perldoc EV::libev>) for more subtle details on watcher semantics or some
57force a specific backend with C<LIBEV_FLAGS>. 63discussion on the available backends, or how to force a specific backend
64with C<LIBEV_FLAGS>, or just about in any case because it has much more
65detailed information.
66
67This module is very fast and scalable. It is actually so fast that you
68can use it through the L<AnyEvent> module, stay portable to other event
69loops (if you don't rely on any watcher types not available through it)
70and still be faster than with any other event loop currently supported in
71Perl.
72
73=head2 MODULE EXPORTS
74
75This module does not export any symbols.
58 76
59=cut 77=cut
60 78
61package EV; 79package EV;
62 80
81no warnings;
63use strict; 82use strict;
64 83
65BEGIN { 84BEGIN {
66 our $VERSION = '1.3'; 85 our $VERSION = '3.6';
67 use XSLoader; 86 use XSLoader;
68 XSLoader::load "EV", $VERSION; 87 XSLoader::load "EV", $VERSION;
69} 88}
70 89
71@EV::IO::ISA = 90@EV::IO::ISA =
72@EV::Timer::ISA = 91@EV::Timer::ISA =
73@EV::Periodic::ISA = 92@EV::Periodic::ISA =
74@EV::Signal::ISA = 93@EV::Signal::ISA =
94@EV::Child::ISA =
95@EV::Stat::ISA =
75@EV::Idle::ISA = 96@EV::Idle::ISA =
76@EV::Prepare::ISA = 97@EV::Prepare::ISA =
77@EV::Check::ISA = 98@EV::Check::ISA =
78@EV::Child::ISA = "EV::Watcher"; 99@EV::Embed::ISA =
100@EV::Fork::ISA =
101@EV::Async::ISA =
102 "EV::Watcher";
103
104@EV::Loop::Default::ISA = "EV::Loop";
105
106=head1 EVENT LOOPS
107
108EV supports multiple event loops: There is a single "default event loop"
109that can handle everything including signals and child watchers, and any
110number of "dynamic event loops" that can use different backends (with
111various limitations), but no child and signal watchers.
112
113You do not have to do anything to create the default event loop: When
114the module is loaded a suitable backend is selected on the premise of
115selecting a working backend (which for example rules out kqueue on most
116BSDs). Modules should, unless they have "special needs" always use the
117default loop as this is fastest (perl-wise), best supported by other
118modules (e.g. AnyEvent or Coro) and most portable event loop.
119
120For specific programs you can create additional event loops dynamically.
121
122If you want to take advantage of kqueue (which often works properly for
123sockets only) even though the default loop doesn't enable it, you can
124I<embed> a kqueue loop into the default loop: running the default loop
125will then also service the kqueue loop to some extent. See the example in
126the section about embed watchers for an example on how to achieve that.
127
128=over 4
129
130=item $loop = new EV::Loop [$flags]
131
132Create a new event loop as per the specified flags. Please refer to
133the C<ev_loop_new ()> function description in the libev documentation
134(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
135or locally-installed as F<EV::libev> manpage) for more info.
136
137The loop will automatically be destroyed when it is no longer referenced
138by any watcher and the loop object goes out of scope.
139
140If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
141is recommended, as only the default event loop is protected by this
142module. If you I<are> embedding this loop in the default loop, this is not
143necessary, as C<EV::embed> automatically does the right thing on fork.
144
145=item $loop->loop_fork
146
147Must be called after a fork in the child, before entering or continuing
148the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
149this function automatically, at some performance loss (refer to the libev
150documentation).
151
152=item $loop->loop_verify
153
154Calls C<ev_verify> to make internal consistency checks (for debugging
155libev) and abort the program if any data structures were found to be
156corrupted.
157
158=item $loop = EV::default_loop [$flags]
159
160Return the default loop (which is a singleton object). Since this module
161already creates the default loop with default flags, specifying flags here
162will not have any effect unless you destroy the default loop first, which
163isn't supported. So in short: don't do it, and if you break it, you get to
164keep the pieces.
165
166=back
167
79 168
80=head1 BASIC INTERFACE 169=head1 BASIC INTERFACE
81 170
82=over 4 171=over 4
83 172
84=item $EV::DIED 173=item $EV::DIED
85 174
86Must contain a reference to a function that is called when a callback 175Must contain a reference to a function that is called when a callback
87throws an exception (with $@ containing thr error). The default prints an 176throws an exception (with $@ containing the error). The default prints an
88informative message and continues. 177informative message and continues.
89 178
90If this callback throws an exception it will be silently ignored. 179If this callback throws an exception it will be silently ignored.
91 180
181=item $flags = EV::supported_backends
182
183=item $flags = EV::recommended_backends
184
185=item $flags = EV::embeddable_backends
186
187Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
188instance of EV, the set of recommended backends (supposed to be good) for
189this platform and the set of embeddable backends (see EMBED WATCHERS).
190
191=item EV::sleep $seconds
192
193Block the process for the given number of (fractional) seconds.
194
92=item $time = EV::time 195=item $time = EV::time
93 196
94Returns the current time in (fractional) seconds since the epoch. 197Returns the current time in (fractional) seconds since the epoch.
95 198
96=item $time = EV::now 199=item $time = EV::now
97 200
201=item $time = $loop->now
202
98Returns the time the last event loop iteration has been started. This 203Returns the time the last event loop iteration has been started. This
99is the time that (relative) timers are based on, and refering to it is 204is the time that (relative) timers are based on, and referring to it is
100usually faster then calling EV::time. 205usually faster then calling EV::time.
101 206
102=item $method = EV::method 207=item EV::now_update
103 208
209=item $loop->now_update
210
211Establishes the current time by querying the kernel, updating the time
212returned by C<EV::now> in the progress. This is a costly operation and
213is usually done automatically within C<EV::loop>.
214
215This function is rarely useful, but when some event callback runs for a
216very long time without entering the event loop, updating libev's idea of
217the current time is a good idea.
218
219=item EV::suspend
220
221=item $loop->suspend
222
223=item EV::resume
224
225=item $loop->resume
226
227These two functions suspend and resume a loop, for use when the loop is
228not used for a while and timeouts should not be processed.
229
230A typical use case would be an interactive program such as a game: When
231the user presses C<^Z> to suspend the game and resumes it an hour later it
232would be best to handle timeouts as if no time had actually passed while
233the program was suspended. This can be achieved by calling C<suspend>
234in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
235C<resume> directly afterwards to resume timer processing.
236
237Effectively, all C<timer> watchers will be delayed by the time spend
238between C<suspend> and C<resume>, and all C<periodic> watchers
239will be rescheduled (that is, they will lose any events that would have
240occured while suspended).
241
242After calling C<suspend> you B<must not> call I<any> function on the given
243loop other than C<resume>, and you B<must not> call C<resume>
244without a previous call to C<suspend>.
245
246Calling C<suspend>/C<resume> has the side effect of updating the event
247loop time (see C<now_update>).
248
249=item $backend = EV::backend
250
251=item $backend = $loop->backend
252
104Returns an integer describing the backend used by libev (EV::METHOD_SELECT 253Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
105or EV::METHOD_EPOLL). 254or EV::BACKEND_EPOLL).
106 255
107=item EV::loop [$flags] 256=item EV::loop [$flags]
257
258=item $loop->loop ([$flags])
108 259
109Begin checking for events and calling callbacks. It returns when a 260Begin checking for events and calling callbacks. It returns when a
110callback calls EV::unloop. 261callback calls EV::unloop.
111 262
112The $flags argument can be one of the following: 263The $flags argument can be one of the following:
115 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 266 EV::LOOP_ONESHOT block at most once (wait, but do not loop)
116 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 267 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
117 268
118=item EV::unloop [$how] 269=item EV::unloop [$how]
119 270
271=item $loop->unloop ([$how])
272
120When called with no arguments or an argument of EV::UNLOOP_ONE, makes the 273When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
121innermost call to EV::loop return. 274innermost call to EV::loop return.
122 275
123When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as 276When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
124fast as possible. 277fast as possible.
125 278
279=item $count = EV::loop_count
280
281=item $count = $loop->loop_count
282
283Return the number of times the event loop has polled for new
284events. Sometimes useful as a generation counter.
285
126=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 286=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
287
288=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
127 289
128This function rolls together an I/O and a timer watcher for a single 290This function rolls together an I/O and a timer watcher for a single
129one-shot event without the need for managing a watcher object. 291one-shot event without the need for managing a watcher object.
130 292
131If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> 293If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
137If timeout is C<undef> or negative, then there will be no 299If timeout is C<undef> or negative, then there will be no
138timeout. Otherwise a EV::timer with this value will be started. 300timeout. Otherwise a EV::timer with this value will be started.
139 301
140When an error occurs or either the timeout or I/O watcher triggers, then 302When an error occurs or either the timeout or I/O watcher triggers, then
141the callback will be called with the received event set (in general 303the callback will be called with the received event set (in general
142you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>, 304you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
143C<EV::WRITE> and C<EV::TIMEOUT>). 305C<EV::WRITE> and C<EV::TIMEOUT>).
144 306
145EV::once doesn't return anything: the watchers stay active till either 307EV::once doesn't return anything: the watchers stay active till either
146of them triggers, then they will be stopped and freed, and the callback 308of them triggers, then they will be stopped and freed, and the callback
147invoked. 309invoked.
148 310
149=back 311=item EV::feed_fd_event ($fd, $revents)
150 312
151=head2 WATCHER 313=item $loop->feed_fd_event ($fd, $revents)
314
315Feed an event on a file descriptor into EV. EV will react to this call as
316if the readyness notifications specified by C<$revents> (a combination of
317C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
318
319=item EV::feed_signal_event ($signal)
320
321Feed a signal event into EV. EV will react to this call as if the signal
322specified by C<$signal> had occured.
323
324=item EV::set_io_collect_interval $time
325
326=item $loop->set_io_collect_interval ($time)
327
328=item EV::set_timeout_collect_interval $time
329
330=item $loop->set_timeout_collect_interval ($time)
331
332These advanced functions set the minimum block interval when polling for I/O events and the minimum
333wait interval for timer events. See the libev documentation at
334L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
335(locally installed as F<EV::libev>) for a more detailed discussion.
336
337=back
338
339
340=head1 WATCHER OBJECTS
152 341
153A watcher is an object that gets created to record your interest in some 342A watcher is an object that gets created to record your interest in some
154event. For instance, if you want to wait for STDIN to become readable, you 343event. For instance, if you want to wait for STDIN to become readable, you
155would create an EV::io watcher for that: 344would create an EV::io watcher for that:
156 345
157 my $watcher = EV::io *STDIN, EV::READ, sub { 346 my $watcher = EV::io *STDIN, EV::READ, sub {
158 my ($watcher, $revents) = @_; 347 my ($watcher, $revents) = @_;
159 warn "yeah, STDIN should not be readable without blocking!\n" 348 warn "yeah, STDIN should now be readable without blocking!\n"
160 }; 349 };
161 350
162All watchers can be active (waiting for events) or inactive (paused). Only 351All watchers can be active (waiting for events) or inactive (paused). Only
163active watchers will have their callbacks invoked. All callbacks will be 352active watchers will have their callbacks invoked. All callbacks will be
164called with at least two arguments: the watcher and a bitmask of received 353called with at least two arguments: the watcher and a bitmask of received
165events. 354events.
166 355
167Each watcher type has its associated bit in revents, so you can use the 356Each watcher type has its associated bit in revents, so you can use the
168same callback for multiple watchers. The event mask is named after the 357same callback for multiple watchers. The event mask is named after the
169type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 358type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
170EV::periodic sets EV::PERIODIC and so on, with the exception of IO events 359EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
171(which can set both EV::READ and EV::WRITE bits), and EV::timer (which 360(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
172uses EV::TIMEOUT). 361uses EV::TIMEOUT).
173 362
174In the rare case where one wants to create a watcher but not start it at 363In the rare case where one wants to create a watcher but not start it at
175the same time, each constructor has a variant with a trailing C<_ns> in 364the same time, each constructor has a variant with a trailing C<_ns> in
181 370
182Also, all methods changing some aspect of a watcher (->set, ->priority, 371Also, all methods changing some aspect of a watcher (->set, ->priority,
183->fh and so on) automatically stop and start it again if it is active, 372->fh and so on) automatically stop and start it again if it is active,
184which means pending events get lost. 373which means pending events get lost.
185 374
186=head2 WATCHER TYPES 375=head2 COMMON WATCHER METHODS
187 376
188Now lets move to the existing watcher types and asociated methods. 377This section lists methods common to all watchers.
189
190The following methods are available for all watchers. Then followes a
191description of each watcher constructor (EV::io, EV::timer, EV::periodic,
192EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by
193any type-specific methods (if any).
194 378
195=over 4 379=over 4
196 380
197=item $w->start 381=item $w->start
198 382
202 386
203=item $w->stop 387=item $w->stop
204 388
205Stop a watcher if it is active. Also clear any pending events (events that 389Stop a watcher if it is active. Also clear any pending events (events that
206have been received but that didn't yet result in a callback invocation), 390have been received but that didn't yet result in a callback invocation),
207regardless of wether the watcher was active or not. 391regardless of whether the watcher was active or not.
208 392
209=item $bool = $w->is_active 393=item $bool = $w->is_active
210 394
211Returns true if the watcher is active, false otherwise. 395Returns true if the watcher is active, false otherwise.
212 396
242The default priority of any newly-created watcher is 0. 426The default priority of any newly-created watcher is 0.
243 427
244Note that the priority semantics have not yet been fleshed out and are 428Note that the priority semantics have not yet been fleshed out and are
245subject to almost certain change. 429subject to almost certain change.
246 430
247=item $w->trigger ($revents) 431=item $w->invoke ($revents)
248 432
249Call the callback *now* with the given event mask. 433Call the callback *now* with the given event mask.
434
435=item $w->feed_event ($revents)
436
437Feed some events on this watcher into EV. EV will react to this call as if
438the watcher had received the given C<$revents> mask.
439
440=item $revents = $w->clear_pending
441
442If the watcher is pending, this function clears its pending status and
443returns its C<$revents> bitset (as if its callback was invoked). If the
444watcher isn't pending it does nothing and returns C<0>.
250 445
251=item $previous_state = $w->keepalive ($bool) 446=item $previous_state = $w->keepalive ($bool)
252 447
253Normally, C<EV::loop> will return when there are no active watchers 448Normally, C<EV::loop> will return when there are no active watchers
254(which is a "deadlock" because no progress can be made anymore). This is 449(which is a "deadlock" because no progress can be made anymore). This is
255convinient because it allows you to start your watchers (and your jobs), 450convinient because it allows you to start your watchers (and your jobs),
256call C<EV::loop> once and when it returns you know that all your jobs are 451call C<EV::loop> once and when it returns you know that all your jobs are
257finished (or they forgot to register some watchers for their task :). 452finished (or they forgot to register some watchers for their task :).
258 453
259Sometimes, however, this gets in your way, for example when you the module 454Sometimes, however, this gets in your way, for example when the module
260that calls C<EV::loop> (usually the main program) is not the same module 455that calls C<EV::loop> (usually the main program) is not the same module
261as a long-living watcher (for example a DNS client module written by 456as a long-living watcher (for example a DNS client module written by
262somebody else even). Then you might want any outstanding requests to be 457somebody else even). Then you might want any outstanding requests to be
263handled, but you would not want to keep C<EV::loop> from returning just 458handled, but you would not want to keep C<EV::loop> from returning just
264because you happen to have this long-running UDP port watcher. 459because you happen to have this long-running UDP port watcher.
265 460
266In this case you can clear the keepalive status, which means that even 461In this case you can clear the keepalive status, which means that even
267though your watcher is active, it won't keep C<EV::loop> from returning. 462though your watcher is active, it won't keep C<EV::loop> from returning.
268 463
269The initial value for keepalive is true (enabled), and you cna change it 464The initial value for keepalive is true (enabled), and you can change it
270any time. 465any time.
271 466
272Example: Register an IO watcher for some UDP socket but do not keep the 467Example: Register an I/O watcher for some UDP socket but do not keep the
273event loop from running just because of that watcher. 468event loop from running just because of that watcher.
274 469
275 my $udp_socket = ... 470 my $udp_socket = ...
276 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 471 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
277 $udp_watcher->keepalive (0); 472 $udp_watcher->keepalive (0);
278 473
474=item $loop = $w->loop
475
476Return the loop that this watcher is attached to.
477
478=back
479
480
481=head1 WATCHER TYPES
482
483Each of the following subsections describes a single watcher type.
484
485=head3 I/O WATCHERS - is this file descriptor readable or writable?
486
487=over 4
488
279=item $w = EV::io $fileno_or_fh, $eventmask, $callback 489=item $w = EV::io $fileno_or_fh, $eventmask, $callback
280 490
281=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 491=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
282 492
493=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
494
495=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
496
283As long as the returned watcher object is alive, call the C<$callback> 497As long as the returned watcher object is alive, call the C<$callback>
284when the events specified in C<$eventmask>. 498when at least one of events specified in C<$eventmask> occurs.
285 499
286The $eventmask can be one or more of these constants ORed together: 500The $eventmask can be one or more of these constants ORed together:
287 501
288 EV::READ wait until read() wouldn't block anymore 502 EV::READ wait until read() wouldn't block anymore
289 EV::WRITE wait until write() wouldn't block anymore 503 EV::WRITE wait until write() wouldn't block anymore
305 519
306=item $old_eventmask = $w->events ($new_eventmask) 520=item $old_eventmask = $w->events ($new_eventmask)
307 521
308Returns the previously set event mask and optionally set a new one. 522Returns the previously set event mask and optionally set a new one.
309 523
524=back
525
526
527=head3 TIMER WATCHERS - relative and optionally repeating timeouts
528
529=over 4
310 530
311=item $w = EV::timer $after, $repeat, $callback 531=item $w = EV::timer $after, $repeat, $callback
312 532
313=item $w = EV::timer_ns $after, $repeat, $callback 533=item $w = EV::timer_ns $after, $repeat, $callback
534
535=item $w = $loop->timer ($after, $repeat, $callback)
536
537=item $w = $loop->timer_ns ($after, $repeat, $callback)
314 538
315Calls the callback after C<$after> seconds (which may be fractional). If 539Calls the callback after C<$after> seconds (which may be fractional). If
316C<$repeat> is non-zero, the timer will be restarted (with the $repeat 540C<$repeat> is non-zero, the timer will be restarted (with the $repeat
317value as $after) after the callback returns. 541value as $after) after the callback returns.
318 542
328 552
329The C<timer_ns> variant doesn't start (activate) the newly created watcher. 553The C<timer_ns> variant doesn't start (activate) the newly created watcher.
330 554
331=item $w->set ($after, $repeat) 555=item $w->set ($after, $repeat)
332 556
333Reconfigures the watcher, see the constructor above for details. Can be at 557Reconfigures the watcher, see the constructor above for details. Can be called at
334any time. 558any time.
335 559
336=item $w->again 560=item $w->again
337 561
338Similar to the C<start> method, but has special semantics for repeating timers: 562Similar to the C<start> method, but has special semantics for repeating timers:
349This behaviour is useful when you have a timeout for some IO 573This behaviour is useful when you have a timeout for some IO
350operation. You create a timer object with the same value for C<$after> and 574operation. You create a timer object with the same value for C<$after> and
351C<$repeat>, and then, in the read/write watcher, run the C<again> method 575C<$repeat>, and then, in the read/write watcher, run the C<again> method
352on the timeout. 576on the timeout.
353 577
578=back
579
580
581=head3 PERIODIC WATCHERS - to cron or not to cron?
582
583=over 4
354 584
355=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback 585=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
356 586
357=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 587=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
588
589=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
590
591=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
358 592
359Similar to EV::timer, but is not based on relative timeouts but on 593Similar to EV::timer, but is not based on relative timeouts but on
360absolute times. Apart from creating "simple" timers that trigger "at" the 594absolute times. Apart from creating "simple" timers that trigger "at" the
361specified time, it can also be used for non-drifting absolute timers and 595specified time, it can also be used for non-drifting absolute timers and
362more complex, cron-like, setups that are not adversely affected by time 596more complex, cron-like, setups that are not adversely affected by time
372This time simply fires at the wallclock time C<$at> and doesn't repeat. It 606This time simply fires at the wallclock time C<$at> and doesn't repeat. It
373will not adjust when a time jump occurs, that is, if it is to be run 607will not adjust when a time jump occurs, that is, if it is to be run
374at January 1st 2011 then it will run when the system time reaches or 608at January 1st 2011 then it will run when the system time reaches or
375surpasses this time. 609surpasses this time.
376 610
377=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 611=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
378 612
379In this mode the watcher will always be scheduled to time out at the 613In this mode the watcher will always be scheduled to time out at the
380next C<$at + N * $interval> time (for some integer N) and then repeat, 614next C<$at + N * $interval> time (for some integer N) and then repeat,
381regardless of any time jumps. 615regardless of any time jumps.
382 616
400time the periodic watcher gets scheduled, the reschedule callback 634time the periodic watcher gets scheduled, the reschedule callback
401($reschedule_cb) will be called with the watcher as first, and the current 635($reschedule_cb) will be called with the watcher as first, and the current
402time as second argument. 636time as second argument.
403 637
404I<This callback MUST NOT stop or destroy this or any other periodic 638I<This callback MUST NOT stop or destroy this or any other periodic
405watcher, ever>. If you need to stop it, return 1e30 and stop it 639watcher, ever, and MUST NOT call any event loop functions or methods>. If
406afterwards. 640you need to stop it, return 1e30 and stop it afterwards. You may create
641and start a C<EV::prepare> watcher for this task.
407 642
408It must return the next time to trigger, based on the passed time value 643It must return the next time to trigger, based on the passed time value
409(that is, the lowest time value larger than to the second argument). It 644(that is, the lowest time value larger than or equal to to the second
410will usually be called just before the callback will be triggered, but 645argument). It will usually be called just before the callback will be
411might be called at other times, too. 646triggered, but might be called at other times, too.
412 647
413This can be used to create very complex timers, such as a timer that 648This can be used to create very complex timers, such as a timer that
414triggers on each midnight, local time (actually 24 hours after the last 649triggers on each midnight, local time (actually 24 hours after the last
415midnight, to keep the example simple. If you know a way to do it correctly 650midnight, to keep the example simple. If you know a way to do it correctly
416in about the same space (without requiring elaborate modules), drop me a 651in about the same space (without requiring elaborate modules), drop me a
430 665
431The C<periodic_ns> variant doesn't start (activate) the newly created watcher. 666The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
432 667
433=item $w->set ($at, $interval, $reschedule_cb) 668=item $w->set ($at, $interval, $reschedule_cb)
434 669
435Reconfigures the watcher, see the constructor above for details. Can be at 670Reconfigures the watcher, see the constructor above for details. Can be called at
436any time. 671any time.
437 672
438=item $w->again 673=item $w->again
439 674
440Simply stops and starts the watcher again. 675Simply stops and starts the watcher again.
441 676
677=item $time = $w->at
678
679Return the time that the watcher is expected to trigger next.
680
681=back
682
683
684=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
685
686=over 4
442 687
443=item $w = EV::signal $signal, $callback 688=item $w = EV::signal $signal, $callback
444 689
445=item $w = EV::signal_ns $signal, $callback 690=item $w = EV::signal_ns $signal, $callback
446 691
447Call the callback when $signal is received (the signal can be specified 692Call the callback when $signal is received (the signal can be specified by
448by number or by name, just as with kill or %SIG). 693number or by name, just as with C<kill> or C<%SIG>).
449 694
450EV will grab the signal for the process (the kernel only allows one 695EV will grab the signal for the process (the kernel only allows one
451component to receive a signal at a time) when you start a signal watcher, 696component to receive a signal at a time) when you start a signal watcher,
452and removes it again when you stop it. Perl does the same when you 697and removes it again when you stop it. Perl does the same when you
453add/remove callbacks to %SIG, so watch out. 698add/remove callbacks to C<%SIG>, so watch out.
454 699
455You can have as many signal watchers per signal as you want. 700You can have as many signal watchers per signal as you want.
456 701
457The C<signal_ns> variant doesn't start (activate) the newly created watcher. 702The C<signal_ns> variant doesn't start (activate) the newly created watcher.
458 703
459=item $w->set ($signal) 704=item $w->set ($signal)
460 705
461Reconfigures the watcher, see the constructor above for details. Can be at 706Reconfigures the watcher, see the constructor above for details. Can be
462any time. 707called at any time.
463 708
464=item $current_signum = $w->signal 709=item $current_signum = $w->signal
465 710
466=item $old_signum = $w->signal ($new_signal) 711=item $old_signum = $w->signal ($new_signal)
467 712
468Returns the previously set signal (always as a number not name) and 713Returns the previously set signal (always as a number not name) and
469optionally set a new one. 714optionally set a new one.
470 715
716=back
471 717
718
719=head3 CHILD WATCHERS - watch out for process status changes
720
721=over 4
722
472=item $w = EV::child $pid, $callback 723=item $w = EV::child $pid, $trace, $callback
473 724
474=item $w = EV::child_ns $pid, $callback 725=item $w = EV::child_ns $pid, $trace, $callback
726
727=item $w = $loop->child ($pid, $trace, $callback)
728
729=item $w = $loop->child_ns ($pid, $trace, $callback)
475 730
476Call the callback when a status change for pid C<$pid> (or any pid 731Call the callback when a status change for pid C<$pid> (or any pid
477if C<$pid> is 0) has been received. More precisely: when the process 732if C<$pid> is 0) has been received (a status change happens when the
733process terminates or is killed, or, when trace is true, additionally when
734it is stopped or continued). More precisely: when the process receives
478receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all 735a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
479changed/zombie children and call the callback. 736changed/zombie children and call the callback.
480 737
481You can access both status and pid by using the C<rstatus> and C<rpid> 738It is valid (and fully supported) to install a child watcher after a child
482methods on the watcher object. 739has exited but before the event loop has started its next iteration (for
740example, first you C<fork>, then the new child process might exit, and
741only then do you install a child watcher in the parent for the new pid).
483 742
743You can access both exit (or tracing) status and pid by using the
744C<rstatus> and C<rpid> methods on the watcher object.
745
484You can have as many pid watchers per pid as you want. 746You can have as many pid watchers per pid as you want, they will all be
747called.
485 748
486The C<child_ns> variant doesn't start (activate) the newly created watcher. 749The C<child_ns> variant doesn't start (activate) the newly created watcher.
487 750
488=item $w->set ($pid) 751=item $w->set ($pid, $trace)
489 752
490Reconfigures the watcher, see the constructor above for details. Can be at 753Reconfigures the watcher, see the constructor above for details. Can be called at
491any time. 754any time.
492 755
493=item $current_pid = $w->pid 756=item $current_pid = $w->pid
494
495=item $old_pid = $w->pid ($new_pid)
496 757
497Returns the previously set process id and optionally set a new one. 758Returns the previously set process id and optionally set a new one.
498 759
499=item $exit_status = $w->rstatus 760=item $exit_status = $w->rstatus
500 761
504=item $pid = $w->rpid 765=item $pid = $w->rpid
505 766
506Return the pid of the awaited child (useful when you have installed a 767Return the pid of the awaited child (useful when you have installed a
507watcher for all pids). 768watcher for all pids).
508 769
770=back
771
772
773=head3 STAT WATCHERS - did the file attributes just change?
774
775=over 4
776
777=item $w = EV::stat $path, $interval, $callback
778
779=item $w = EV::stat_ns $path, $interval, $callback
780
781=item $w = $loop->stat ($path, $interval, $callback)
782
783=item $w = $loop->stat_ns ($path, $interval, $callback)
784
785Call the callback when a file status change has been detected on
786C<$path>. The C<$path> does not need to exist, changing from "path exists"
787to "path does not exist" is a status change like any other.
788
789The C<$interval> is a recommended polling interval for systems where
790OS-supported change notifications don't exist or are not supported. If
791you use C<0> then an unspecified default is used (which is highly
792recommended!), which is to be expected to be around five seconds usually.
793
794This watcher type is not meant for massive numbers of stat watchers,
795as even with OS-supported change notifications, this can be
796resource-intensive.
797
798The C<stat_ns> variant doesn't start (activate) the newly created watcher.
799
800=item ... = $w->stat
801
802This call is very similar to the perl C<stat> built-in: It stats (using
803C<lstat>) the path specified in the watcher and sets perls stat cache (as
804well as EV's idea of the current stat values) to the values found.
805
806In scalar context, a boolean is return indicating success or failure of
807the stat. In list context, the same 13-value list as with stat is returned
808(except that the blksize and blocks fields are not reliable).
809
810In the case of an error, errno is set to C<ENOENT> (regardless of the
811actual error value) and the C<nlink> value is forced to zero (if the stat
812was successful then nlink is guaranteed to be non-zero).
813
814See also the next two entries for more info.
815
816=item ... = $w->attr
817
818Just like C<< $w->stat >>, but without the initial stat'ing: this returns
819the values most recently detected by EV. See the next entry for more info.
820
821=item ... = $w->prev
822
823Just like C<< $w->stat >>, but without the initial stat'ing: this returns
824the previous set of values, before the change.
825
826That is, when the watcher callback is invoked, C<< $w->prev >> will be set
827to the values found I<before> a change was detected, while C<< $w->attr >>
828returns the values found leading to the change detection. The difference (if any)
829between C<prev> and C<attr> is what triggered the callback.
830
831If you did something to the filesystem object and do not want to trigger
832yet another change, you can call C<stat> to update EV's idea of what the
833current attributes are.
834
835=item $w->set ($path, $interval)
836
837Reconfigures the watcher, see the constructor above for details. Can be
838called at any time.
839
840=item $current_path = $w->path
841
842=item $old_path = $w->path ($new_path)
843
844Returns the previously set path and optionally set a new one.
845
846=item $current_interval = $w->interval
847
848=item $old_interval = $w->interval ($new_interval)
849
850Returns the previously set interval and optionally set a new one. Can be
851used to query the actual interval used.
852
853=back
854
855
856=head3 IDLE WATCHERS - when you've got nothing better to do...
857
858=over 4
509 859
510=item $w = EV::idle $callback 860=item $w = EV::idle $callback
511 861
512=item $w = EV::idle_ns $callback 862=item $w = EV::idle_ns $callback
513 863
514Call the callback when there are no pending io, timer/periodic, signal or 864=item $w = $loop->idle ($callback)
515child events, i.e. when the process is idle. 865
866=item $w = $loop->idle_ns ($callback)
867
868Call the callback when there are no other pending watchers of the same or
869higher priority (excluding check, prepare and other idle watchers of the
870same or lower priority, of course). They are called idle watchers because
871when the watcher is the highest priority pending event in the process, the
872process is considered to be idle at that priority.
873
874If you want a watcher that is only ever called when I<no> other events are
875outstanding you have to set the priority to C<EV::MINPRI>.
516 876
517The process will not block as long as any idle watchers are active, and 877The process will not block as long as any idle watchers are active, and
518they will be called repeatedly until stopped. 878they will be called repeatedly until stopped.
519 879
880For example, if you have idle watchers at priority C<0> and C<1>, and
881an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
882and the I/O watcher will always run when ready. Only when the idle watcher
883at priority C<1> is stopped and the I/O watcher at priority C<0> is not
884pending with the C<0>-priority idle watcher be invoked.
885
520The C<idle_ns> variant doesn't start (activate) the newly created watcher. 886The C<idle_ns> variant doesn't start (activate) the newly created watcher.
521 887
888=back
889
890
891=head3 PREPARE WATCHERS - customise your event loop!
892
893=over 4
522 894
523=item $w = EV::prepare $callback 895=item $w = EV::prepare $callback
524 896
525=item $w = EV::prepare_ns $callback 897=item $w = EV::prepare_ns $callback
898
899=item $w = $loop->prepare ($callback)
900
901=item $w = $loop->prepare_ns ($callback)
526 902
527Call the callback just before the process would block. You can still 903Call the callback just before the process would block. You can still
528create/modify any watchers at this point. 904create/modify any watchers at this point.
529 905
530See the EV::check watcher, below, for explanations and an example. 906See the EV::check watcher, below, for explanations and an example.
531 907
532The C<prepare_ns> variant doesn't start (activate) the newly created watcher. 908The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
533 909
910=back
911
912
913=head3 CHECK WATCHERS - customise your event loop even more!
914
915=over 4
534 916
535=item $w = EV::check $callback 917=item $w = EV::check $callback
536 918
537=item $w = EV::check_ns $callback 919=item $w = EV::check_ns $callback
920
921=item $w = $loop->check ($callback)
922
923=item $w = $loop->check_ns ($callback)
538 924
539Call the callback just after the process wakes up again (after it has 925Call the callback just after the process wakes up again (after it has
540gathered events), but before any other callbacks have been invoked. 926gathered events), but before any other callbacks have been invoked.
541 927
542This is used to integrate other event-based software into the EV 928This is used to integrate other event-based software into the EV
552 or return; 938 or return;
553 939
554 # make the dispatcher handle any outstanding stuff 940 # make the dispatcher handle any outstanding stuff
555 ... not shown 941 ... not shown
556 942
557 # create an IO watcher for each and every socket 943 # create an I/O watcher for each and every socket
558 @snmp_watcher = ( 944 @snmp_watcher = (
559 (map { EV::io $_, EV::READ, sub { } } 945 (map { EV::io $_, EV::READ, sub { } }
560 keys %{ $dispatcher->{_descriptors} }), 946 keys %{ $dispatcher->{_descriptors} }),
561 947
562 EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] 948 EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
577 # make the dispatcher handle any new stuff 963 # make the dispatcher handle any new stuff
578 ... not shown 964 ... not shown
579 }; 965 };
580 966
581The callbacks of the created watchers will not be called as the watchers 967The callbacks of the created watchers will not be called as the watchers
582are destroyed before this cna happen (remember EV::check gets called 968are destroyed before this can happen (remember EV::check gets called
583first). 969first).
584 970
585The C<check_ns> variant doesn't start (activate) the newly created watcher. 971The C<check_ns> variant doesn't start (activate) the newly created watcher.
586 972
587=back 973=back
974
975
976=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
977
978Fork watchers are called when a C<fork ()> was detected. The invocation
979is done before the event loop blocks next and before C<check> watchers
980are being called, and only in the child after the fork.
981
982=over 4
983
984=item $w = EV::fork $callback
985
986=item $w = EV::fork_ns $callback
987
988=item $w = $loop->fork ($callback)
989
990=item $w = $loop->fork_ns ($callback)
991
992Call the callback before the event loop is resumed in the child process
993after a fork.
994
995The C<fork_ns> variant doesn't start (activate) the newly created watcher.
996
997=back
998
999
1000=head3 EMBED WATCHERS - when one backend isn't enough...
1001
1002This is a rather advanced watcher type that lets you embed one event loop
1003into another (currently only IO events are supported in the embedded
1004loop, other types of watchers might be handled in a delayed or incorrect
1005fashion and must not be used).
1006
1007See the libev documentation at
1008L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
1009(locally installed as F<EV::libev>) for more details.
1010
1011In short, this watcher is most useful on BSD systems without working
1012kqueue to still be able to handle a large number of sockets:
1013
1014 my $socket_loop;
1015
1016 # check wether we use SELECT or POLL _and_ KQUEUE is supported
1017 if (
1018 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
1019 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
1020 ) {
1021 # use kqueue for sockets
1022 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
1023 }
1024
1025 # use the default loop otherwise
1026 $socket_loop ||= EV::default_loop;
1027
1028=over 4
1029
1030=item $w = EV::embed $otherloop[, $callback]
1031
1032=item $w = EV::embed_ns $otherloop[, $callback]
1033
1034=item $w = $loop->embed ($otherloop[, $callback])
1035
1036=item $w = $loop->embed_ns ($otherloop[, $callback])
1037
1038Call the callback when the embedded event loop (C<$otherloop>) has any
1039I/O activity. The C<$callback> is optional: if it is missing, then the
1040embedded event loop will be managed automatically (which is recommended),
1041otherwise you have to invoke C<sweep> yourself.
1042
1043The C<embed_ns> variant doesn't start (activate) the newly created watcher.
1044
1045=back
1046
1047=head3 ASYNC WATCHERS - how to wake up another event loop
1048
1049Async watchers are provided by EV, but have little use in perl directly, as perl
1050neither supports threads nor direct access to signal handlers or other
1051contexts where they could be of value.
1052
1053It is, however, possible to use them from the XS level.
1054
1055Please see the libev documentation for further details.
1056
1057=over 4
1058
1059=item $w = EV::async $callback
1060
1061=item $w = EV::async_ns $callback
1062
1063=item $w->send
1064
1065=item $bool = $w->async_pending
1066
1067=back
1068
1069
1070=head1 PERL SIGNALS
1071
1072While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
1073with EV is as the same as any other C library: Perl-signals will only be
1074handled when Perl runs, which means your signal handler might be invoked
1075only the next time an event callback is invoked.
1076
1077The solution is to use EV signal watchers (see C<EV::signal>), which will
1078ensure proper operations with regards to other event watchers.
1079
1080If you cannot do this for whatever reason, you can also force a watcher
1081to be called on every event loop iteration by installing a C<EV::check>
1082watcher:
1083
1084 my $async_check = EV::check sub { };
1085
1086This ensures that perl gets into control for a short time to handle any
1087pending signals, and also ensures (slightly) slower overall operation.
588 1088
589=head1 THREADS 1089=head1 THREADS
590 1090
591Threads are not supported by this module in any way. Perl pseudo-threads 1091Threads are not supported by this module in any way. Perl pseudo-threads
592is evil stuff and must die. As soon as Perl gains real threads I will work 1092is evil stuff and must die. As soon as Perl gains real threads I will work
614our $DIED = sub { 1114our $DIED = sub {
615 warn "EV: error in callback (ignoring): $@"; 1115 warn "EV: error in callback (ignoring): $@";
616}; 1116};
617 1117
618default_loop 1118default_loop
619 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; 1119 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
620 1120
6211; 11211;
622 1122
623=head1 SEE ALSO 1123=head1 SEE ALSO
624 1124
625 L<EV::DNS>. 1125L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
1126event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
1127coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1128event-loop agnostic and portable event driven programming.
626 1129
627=head1 AUTHOR 1130=head1 AUTHOR
628 1131
629 Marc Lehmann <schmorp@schmorp.de> 1132 Marc Lehmann <schmorp@schmorp.de>
630 http://home.schmorp.de/ 1133 http://home.schmorp.de/
631 1134
632=cut 1135=cut
633 1136

Diff Legend

Removed lines
+ Added lines
< Changed lines
> Changed lines