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Revision 1.61 by root, Thu Dec 6 03:13:07 2007 UTC vs.
Revision 1.104 by root, Thu Oct 2 12:26:25 2008 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 55
56=head1 DESCRIPTION 56=head1 DESCRIPTION
57 57
58This module provides an interface to libev 58This module provides an interface to libev
59(L<http://software.schmorp.de/pkg/libev.html>). While the documentation 59(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
60below is comprehensive, one might also consult the documentation of libev 60below is comprehensive, one might also consult the documentation of
61itself (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
62watcher semantics or some discussion on the available backends, or how to 62F<perldoc EV::c_doc>) for more subtle details on watcher semantics or some
63force 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.
64 72
65=cut 73=cut
66 74
67package EV; 75package EV;
68 76
77no warnings;
69use strict; 78use strict;
70 79
71BEGIN { 80BEGIN {
72 our $VERSION = '1.6'; 81 our $VERSION = '3.44';
73 use XSLoader; 82 use XSLoader;
74 XSLoader::load "EV", $VERSION; 83 XSLoader::load "EV", $VERSION;
75} 84}
76 85
77@EV::IO::ISA = 86@EV::IO::ISA =
83@EV::Idle::ISA = 92@EV::Idle::ISA =
84@EV::Prepare::ISA = 93@EV::Prepare::ISA =
85@EV::Check::ISA = 94@EV::Check::ISA =
86@EV::Embed::ISA = 95@EV::Embed::ISA =
87@EV::Fork::ISA = 96@EV::Fork::ISA =
97@EV::Async::ISA =
88 "EV::Watcher"; 98 "EV::Watcher";
89 99
100@EV::Loop::Default::ISA = "EV::Loop";
101
102=head1 EVENT LOOPS
103
104EV supports multiple event loops: There is a single "default event loop"
105that can handle everything including signals and child watchers, and any
106number of "dynamic event loops" that can use different backends (with
107various limitations), but no child and signal watchers.
108
109You do not have to do anything to create the default event loop: When
110the module is loaded a suitable backend is selected on the premise of
111selecting a working backend (which for example rules out kqueue on most
112BSDs). Modules should, unless they have "special needs" always use the
113default loop as this is fastest (perl-wise), best supported by other
114modules (e.g. AnyEvent or Coro) and most portable event loop.
115
116For specific programs you can create additional event loops dynamically.
117
118If you want to take avdantage of kqueue (which often works properly for
119sockets only) even though the default loop doesn't enable it, you can
120I<embed> a kqueue loop into the default loop: running the default loop
121will then also service the kqueue loop to some extent. See the example in
122the section about embed watchers for an example on how to achieve that.
123
124=over 4
125
126=item $loop = new EV::loop [$flags]
127
128Create a new event loop as per the specified flags. Please refer to
129the C<ev_loop_new ()> function description in the libev documentation
130(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
131or locally-installed as F<EV::c_doc> manpage) for more info.
132
133The loop will automatically be destroyed when it is no longer referenced
134by any watcher and the loop object goes out of scope.
135
136If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
137is recommended, as only the default event loop is protected by this
138module. If you I<are> embedding this loop in the default loop, this is not
139necessary, as C<EV::embed> automatically does the right thing on fork.
140
141=item $loop->loop_fork
142
143Must be called after a fork in the child, before entering or continuing
144the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
145this function automatically, at some performance loss (refer to the libev
146documentation).
147
148=item $loop->loop_verify
149
150Calls C<ev_verify> to make internal consistency checks (for debugging
151libev) and abort the program if any data structures were found to be
152corrupted.
153
154=item $loop = EV::default_loop [$flags]
155
156Return the default loop (which is a singleton object). Since this module
157already creates the default loop with default flags, specifying flags here
158will not have any effect unless you destroy the default loop first, which
159isn't supported. So in short: don't do it, and if you break it, you get to
160keep the pieces.
161
162=back
163
164
90=head1 BASIC INTERFACE 165=head1 BASIC INTERFACE
91 166
92=over 4 167=over 4
93 168
94=item $EV::DIED 169=item $EV::DIED
95 170
96Must contain a reference to a function that is called when a callback 171Must contain a reference to a function that is called when a callback
97throws an exception (with $@ containing thr error). The default prints an 172throws an exception (with $@ containing the error). The default prints an
98informative message and continues. 173informative message and continues.
99 174
100If this callback throws an exception it will be silently ignored. 175If this callback throws an exception it will be silently ignored.
101 176
177=item $flags = EV::supported_backends
178
179=item $flags = EV::recommended_backends
180
181=item $flags = EV::embeddable_backends
182
183Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
184instance of EV, the set of recommended backends (supposed to be good) for
185this platform and the set of embeddable backends (see EMBED WATCHERS).
186
187=item EV::sleep $seconds
188
189Block the process for the given number of (fractional) seconds.
190
102=item $time = EV::time 191=item $time = EV::time
103 192
104Returns the current time in (fractional) seconds since the epoch. 193Returns the current time in (fractional) seconds since the epoch.
105 194
106=item $time = EV::now 195=item $time = EV::now
196
197=item $time = $loop->now
107 198
108Returns the time the last event loop iteration has been started. This 199Returns the time the last event loop iteration has been started. This
109is the time that (relative) timers are based on, and refering to it is 200is the time that (relative) timers are based on, and refering to it is
110usually faster then calling EV::time. 201usually faster then calling EV::time.
111 202
112=item $method = EV::method 203=item $backend = EV::backend
204
205=item $backend = $loop->backend
113 206
114Returns an integer describing the backend used by libev (EV::METHOD_SELECT 207Returns an integer describing the backend used by libev (EV::METHOD_SELECT
115or EV::METHOD_EPOLL). 208or EV::METHOD_EPOLL).
116 209
117=item EV::loop [$flags] 210=item EV::loop [$flags]
211
212=item $loop->loop ([$flags])
118 213
119Begin checking for events and calling callbacks. It returns when a 214Begin checking for events and calling callbacks. It returns when a
120callback calls EV::unloop. 215callback calls EV::unloop.
121 216
122The $flags argument can be one of the following: 217The $flags argument can be one of the following:
125 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 220 EV::LOOP_ONESHOT block at most once (wait, but do not loop)
126 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 221 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
127 222
128=item EV::unloop [$how] 223=item EV::unloop [$how]
129 224
225=item $loop->unloop ([$how])
226
130When called with no arguments or an argument of EV::UNLOOP_ONE, makes the 227When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
131innermost call to EV::loop return. 228innermost call to EV::loop return.
132 229
133When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as 230When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
134fast as possible. 231fast as possible.
135 232
136=item $count = EV::loop_count 233=item $count = EV::loop_count
137 234
235=item $count = $loop->loop_count
236
138Return the number of times the event loop has polled for new 237Return the number of times the event loop has polled for new
139events. Sometiems useful as a generation counter. 238events. Sometiems useful as a generation counter.
140 239
141=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 240=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
241
242=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
142 243
143This function rolls together an I/O and a timer watcher for a single 244This function rolls together an I/O and a timer watcher for a single
144one-shot event without the need for managing a watcher object. 245one-shot event without the need for managing a watcher object.
145 246
146If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> 247If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
152If timeout is C<undef> or negative, then there will be no 253If timeout is C<undef> or negative, then there will be no
153timeout. Otherwise a EV::timer with this value will be started. 254timeout. Otherwise a EV::timer with this value will be started.
154 255
155When an error occurs or either the timeout or I/O watcher triggers, then 256When an error occurs or either the timeout or I/O watcher triggers, then
156the callback will be called with the received event set (in general 257the callback will be called with the received event set (in general
157you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>, 258you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
158C<EV::WRITE> and C<EV::TIMEOUT>). 259C<EV::WRITE> and C<EV::TIMEOUT>).
159 260
160EV::once doesn't return anything: the watchers stay active till either 261EV::once doesn't return anything: the watchers stay active till either
161of them triggers, then they will be stopped and freed, and the callback 262of them triggers, then they will be stopped and freed, and the callback
162invoked. 263invoked.
163 264
164=back 265=item EV::feed_fd_event ($fd, $revents)
165 266
267=item $loop->feed_fd_event ($fd, $revents)
268
269Feed an event on a file descriptor into EV. EV will react to this call as
270if the readyness notifications specified by C<$revents> (a combination of
271C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
272
273=item EV::feed_signal_event ($signal)
274
275Feed a signal event into EV. EV will react to this call as if the signal
276specified by C<$signal> had occured.
277
278=item EV::set_io_collect_interval $time
279
280=item $loop->set_io_collect_interval ($time)
281
282=item EV::set_timeout_collect_interval $time
283
284=item $loop->set_timeout_collect_interval ($time)
285
286These advanced functions set the minimum block interval when polling for I/O events and the minimum
287wait interval for timer events. See the libev documentation at
288L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
289(locally installed as F<EV::c_doc>) for a more detailed discussion.
290
291=back
292
293
166=head2 WATCHER OBJECTS 294=head1 WATCHER OBJECTS
167 295
168A watcher is an object that gets created to record your interest in some 296A watcher is an object that gets created to record your interest in some
169event. For instance, if you want to wait for STDIN to become readable, you 297event. For instance, if you want to wait for STDIN to become readable, you
170would create an EV::io watcher for that: 298would create an EV::io watcher for that:
171 299
172 my $watcher = EV::io *STDIN, EV::READ, sub { 300 my $watcher = EV::io *STDIN, EV::READ, sub {
173 my ($watcher, $revents) = @_; 301 my ($watcher, $revents) = @_;
174 warn "yeah, STDIN should not be readable without blocking!\n" 302 warn "yeah, STDIN should now be readable without blocking!\n"
175 }; 303 };
176 304
177All watchers can be active (waiting for events) or inactive (paused). Only 305All watchers can be active (waiting for events) or inactive (paused). Only
178active watchers will have their callbacks invoked. All callbacks will be 306active watchers will have their callbacks invoked. All callbacks will be
179called with at least two arguments: the watcher and a bitmask of received 307called with at least two arguments: the watcher and a bitmask of received
180events. 308events.
181 309
182Each watcher type has its associated bit in revents, so you can use the 310Each watcher type has its associated bit in revents, so you can use the
183same callback for multiple watchers. The event mask is named after the 311same callback for multiple watchers. The event mask is named after the
184type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 312type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
185EV::periodic sets EV::PERIODIC and so on, with the exception of IO events 313EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
186(which can set both EV::READ and EV::WRITE bits), and EV::timer (which 314(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
187uses EV::TIMEOUT). 315uses EV::TIMEOUT).
188 316
189In the rare case where one wants to create a watcher but not start it at 317In the rare case where one wants to create a watcher but not start it at
190the same time, each constructor has a variant with a trailing C<_ns> in 318the same time, each constructor has a variant with a trailing C<_ns> in
212 340
213=item $w->stop 341=item $w->stop
214 342
215Stop a watcher if it is active. Also clear any pending events (events that 343Stop a watcher if it is active. Also clear any pending events (events that
216have been received but that didn't yet result in a callback invocation), 344have been received but that didn't yet result in a callback invocation),
217regardless of wether the watcher was active or not. 345regardless of whether the watcher was active or not.
218 346
219=item $bool = $w->is_active 347=item $bool = $w->is_active
220 348
221Returns true if the watcher is active, false otherwise. 349Returns true if the watcher is active, false otherwise.
222 350
252The default priority of any newly-created watcher is 0. 380The default priority of any newly-created watcher is 0.
253 381
254Note that the priority semantics have not yet been fleshed out and are 382Note that the priority semantics have not yet been fleshed out and are
255subject to almost certain change. 383subject to almost certain change.
256 384
257=item $w->trigger ($revents) 385=item $w->invoke ($revents)
258 386
259Call the callback *now* with the given event mask. 387Call the callback *now* with the given event mask.
388
389=item $w->feed_event ($revents)
390
391Feed some events on this watcher into EV. EV will react to this call as if
392the watcher had received the given C<$revents> mask.
393
394=item $revents = $w->clear_pending
395
396If the watcher is pending, this function clears its pending status and
397returns its C<$revents> bitset (as if its callback was invoked). If the
398watcher isn't pending it does nothing and returns C<0>.
260 399
261=item $previous_state = $w->keepalive ($bool) 400=item $previous_state = $w->keepalive ($bool)
262 401
263Normally, C<EV::loop> will return when there are no active watchers 402Normally, C<EV::loop> will return when there are no active watchers
264(which is a "deadlock" because no progress can be made anymore). This is 403(which is a "deadlock" because no progress can be made anymore). This is
265convinient because it allows you to start your watchers (and your jobs), 404convinient because it allows you to start your watchers (and your jobs),
266call C<EV::loop> once and when it returns you know that all your jobs are 405call C<EV::loop> once and when it returns you know that all your jobs are
267finished (or they forgot to register some watchers for their task :). 406finished (or they forgot to register some watchers for their task :).
268 407
269Sometimes, however, this gets in your way, for example when you the module 408Sometimes, however, this gets in your way, for example when the module
270that calls C<EV::loop> (usually the main program) is not the same module 409that calls C<EV::loop> (usually the main program) is not the same module
271as a long-living watcher (for example a DNS client module written by 410as a long-living watcher (for example a DNS client module written by
272somebody else even). Then you might want any outstanding requests to be 411somebody else even). Then you might want any outstanding requests to be
273handled, but you would not want to keep C<EV::loop> from returning just 412handled, but you would not want to keep C<EV::loop> from returning just
274because you happen to have this long-running UDP port watcher. 413because you happen to have this long-running UDP port watcher.
277though your watcher is active, it won't keep C<EV::loop> from returning. 416though your watcher is active, it won't keep C<EV::loop> from returning.
278 417
279The initial value for keepalive is true (enabled), and you cna change it 418The initial value for keepalive is true (enabled), and you cna change it
280any time. 419any time.
281 420
282Example: Register an IO watcher for some UDP socket but do not keep the 421Example: Register an I/O watcher for some UDP socket but do not keep the
283event loop from running just because of that watcher. 422event loop from running just because of that watcher.
284 423
285 my $udp_socket = ... 424 my $udp_socket = ...
286 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 425 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
287 $udp_watcher->keepalive (0); 426 $udp_watcher->keepalive (0);
288 427
289=back 428=item $loop = $w->loop
290 429
430Return the loop that this watcher is attached to.
291 431
432=back
433
434
292=head2 WATCHER TYPES 435=head1 WATCHER TYPES
293 436
294Each of the following subsections describes a single watcher type. 437Each of the following subsections describes a single watcher type.
295 438
296=head3 IO WATCHERS - is this file descriptor readable or writable? 439=head3 I/O WATCHERS - is this file descriptor readable or writable?
297 440
298=over 4 441=over 4
299 442
300=item $w = EV::io $fileno_or_fh, $eventmask, $callback 443=item $w = EV::io $fileno_or_fh, $eventmask, $callback
301 444
302=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 445=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
446
447=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
448
449=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
303 450
304As long as the returned watcher object is alive, call the C<$callback> 451As long as the returned watcher object is alive, call the C<$callback>
305when at least one of events specified in C<$eventmask> occurs. 452when at least one of events specified in C<$eventmask> occurs.
306 453
307The $eventmask can be one or more of these constants ORed together: 454The $eventmask can be one or more of these constants ORed together:
336=over 4 483=over 4
337 484
338=item $w = EV::timer $after, $repeat, $callback 485=item $w = EV::timer $after, $repeat, $callback
339 486
340=item $w = EV::timer_ns $after, $repeat, $callback 487=item $w = EV::timer_ns $after, $repeat, $callback
488
489=item $w = $loop->timer ($after, $repeat, $callback)
490
491=item $w = $loop->timer_ns ($after, $repeat, $callback)
341 492
342Calls the callback after C<$after> seconds (which may be fractional). If 493Calls the callback after C<$after> seconds (which may be fractional). If
343C<$repeat> is non-zero, the timer will be restarted (with the $repeat 494C<$repeat> is non-zero, the timer will be restarted (with the $repeat
344value as $after) after the callback returns. 495value as $after) after the callback returns.
345 496
386=over 4 537=over 4
387 538
388=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback 539=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
389 540
390=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 541=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
542
543=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
544
545=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
391 546
392Similar to EV::timer, but is not based on relative timeouts but on 547Similar to EV::timer, but is not based on relative timeouts but on
393absolute times. Apart from creating "simple" timers that trigger "at" the 548absolute times. Apart from creating "simple" timers that trigger "at" the
394specified time, it can also be used for non-drifting absolute timers and 549specified time, it can also be used for non-drifting absolute timers and
395more complex, cron-like, setups that are not adversely affected by time 550more complex, cron-like, setups that are not adversely affected by time
405This time simply fires at the wallclock time C<$at> and doesn't repeat. It 560This time simply fires at the wallclock time C<$at> and doesn't repeat. It
406will not adjust when a time jump occurs, that is, if it is to be run 561will not adjust when a time jump occurs, that is, if it is to be run
407at January 1st 2011 then it will run when the system time reaches or 562at January 1st 2011 then it will run when the system time reaches or
408surpasses this time. 563surpasses this time.
409 564
410=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 565=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
411 566
412In this mode the watcher will always be scheduled to time out at the 567In this mode the watcher will always be scheduled to time out at the
413next C<$at + N * $interval> time (for some integer N) and then repeat, 568next C<$at + N * $interval> time (for some integer N) and then repeat,
414regardless of any time jumps. 569regardless of any time jumps.
415 570
433time the periodic watcher gets scheduled, the reschedule callback 588time the periodic watcher gets scheduled, the reschedule callback
434($reschedule_cb) will be called with the watcher as first, and the current 589($reschedule_cb) will be called with the watcher as first, and the current
435time as second argument. 590time as second argument.
436 591
437I<This callback MUST NOT stop or destroy this or any other periodic 592I<This callback MUST NOT stop or destroy this or any other periodic
438watcher, ever>. If you need to stop it, return 1e30 and stop it 593watcher, ever, and MUST NOT call any event loop functions or methods>. If
439afterwards. 594you need to stop it, return 1e30 and stop it afterwards. You may create
595and start a C<EV::prepare> watcher for this task.
440 596
441It must return the next time to trigger, based on the passed time value 597It must return the next time to trigger, based on the passed time value
442(that is, the lowest time value larger than to the second argument). It 598(that is, the lowest time value larger than or equal to to the second
443will usually be called just before the callback will be triggered, but 599argument). It will usually be called just before the callback will be
444might be called at other times, too. 600triggered, but might be called at other times, too.
445 601
446This can be used to create very complex timers, such as a timer that 602This can be used to create very complex timers, such as a timer that
447triggers on each midnight, local time (actually 24 hours after the last 603triggers on each midnight, local time (actually 24 hours after the last
448midnight, to keep the example simple. If you know a way to do it correctly 604midnight, to keep the example simple. If you know a way to do it correctly
449in about the same space (without requiring elaborate modules), drop me a 605in about the same space (without requiring elaborate modules), drop me a
470 626
471=item $w->again 627=item $w->again
472 628
473Simply stops and starts the watcher again. 629Simply stops and starts the watcher again.
474 630
631=item $time = $w->at
632
633Return the time that the watcher is expected to trigger next.
634
475=back 635=back
476 636
477 637
478=head3 SIGNAL WATCHERS - signal me when a signal gets signalled! 638=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
479 639
512 672
513=head3 CHILD WATCHERS - watch out for process status changes 673=head3 CHILD WATCHERS - watch out for process status changes
514 674
515=over 4 675=over 4
516 676
517=item $w = EV::child $pid, $callback 677=item $w = EV::child $pid, $trace, $callback
518 678
519=item $w = EV::child_ns $pid, $callback 679=item $w = EV::child_ns $pid, $trace, $callback
520 680
681=item $w = $loop->child ($pid, $trace, $callback)
682
683=item $w = $loop->child_ns ($pid, $trace, $callback)
684
521Call the callback when a status change for pid C<$pid> (or any pid if 685Call the callback when a status change for pid C<$pid> (or any pid
522C<$pid> is 0) has been received. More precisely: when the process receives 686if C<$pid> is 0) has been received (a status change happens when the
687process terminates or is killed, or, when trace is true, additionally when
688it is stopped or continued). More precisely: when the process receives
523a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all 689a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
524changed/zombie children and call the callback. 690changed/zombie children and call the callback.
525 691
526It is valid (and fully supported) to install a child watcher after a child 692It is valid (and fully supported) to install a child watcher after a child
527has exited but before the event loop has started its next iteration (for 693has exited but before the event loop has started its next iteration (for
534You can have as many pid watchers per pid as you want, they will all be 700You can have as many pid watchers per pid as you want, they will all be
535called. 701called.
536 702
537The C<child_ns> variant doesn't start (activate) the newly created watcher. 703The C<child_ns> variant doesn't start (activate) the newly created watcher.
538 704
539=item $w->set ($pid) 705=item $w->set ($pid, $trace)
540 706
541Reconfigures the watcher, see the constructor above for details. Can be called at 707Reconfigures the watcher, see the constructor above for details. Can be called at
542any time. 708any time.
543 709
544=item $current_pid = $w->pid 710=item $current_pid = $w->pid
545 711
546=item $old_pid = $w->pid ($new_pid)
547
548Returns the previously set process id and optionally set a new one. 712Returns the previously set process id and optionally set a new one.
549 713
550=item $exit_status = $w->rstatus 714=item $exit_status = $w->rstatus
551 715
552Return the exit/wait status (as returned by waitpid, see the waitpid entry 716Return the exit/wait status (as returned by waitpid, see the waitpid entry
565=over 4 729=over 4
566 730
567=item $w = EV::stat $path, $interval, $callback 731=item $w = EV::stat $path, $interval, $callback
568 732
569=item $w = EV::stat_ns $path, $interval, $callback 733=item $w = EV::stat_ns $path, $interval, $callback
734
735=item $w = $loop->stat ($path, $interval, $callback)
736
737=item $w = $loop->stat_ns ($path, $interval, $callback)
570 738
571Call the callback when a file status change has been detected on 739Call the callback when a file status change has been detected on
572C<$path>. The C<$path> does not need to exist, changing from "path exists" 740C<$path>. The C<$path> does not need to exist, changing from "path exists"
573to "path does not exist" is a status change like any other. 741to "path does not exist" is a status change like any other.
574 742
645 813
646=item $w = EV::idle $callback 814=item $w = EV::idle $callback
647 815
648=item $w = EV::idle_ns $callback 816=item $w = EV::idle_ns $callback
649 817
650Call the callback when there are no pending io, timer/periodic, signal or 818=item $w = $loop->idle ($callback)
651child events, i.e. when the process is idle. 819
820=item $w = $loop->idle_ns ($callback)
821
822Call the callback when there are no other pending watchers of the same or
823higher priority (excluding check, prepare and other idle watchers of the
824same or lower priority, of course). They are called idle watchers because
825when the watcher is the highest priority pending event in the process, the
826process is considered to be idle at that priority.
827
828If you want a watcher that is only ever called when I<no> other events are
829outstanding you have to set the priority to C<EV::MINPRI>.
652 830
653The process will not block as long as any idle watchers are active, and 831The process will not block as long as any idle watchers are active, and
654they will be called repeatedly until stopped. 832they will be called repeatedly until stopped.
655 833
834For example, if you have idle watchers at priority C<0> and C<1>, and
835an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
836and the I/O watcher will always run when ready. Only when the idle watcher
837at priority C<1> is stopped and the I/O watcher at priority C<0> is not
838pending with the C<0>-priority idle watcher be invoked.
839
656The C<idle_ns> variant doesn't start (activate) the newly created watcher. 840The C<idle_ns> variant doesn't start (activate) the newly created watcher.
657 841
658=back 842=back
659 843
660 844
663=over 4 847=over 4
664 848
665=item $w = EV::prepare $callback 849=item $w = EV::prepare $callback
666 850
667=item $w = EV::prepare_ns $callback 851=item $w = EV::prepare_ns $callback
852
853=item $w = $loop->prepare ($callback)
854
855=item $w = $loop->prepare_ns ($callback)
668 856
669Call the callback just before the process would block. You can still 857Call the callback just before the process would block. You can still
670create/modify any watchers at this point. 858create/modify any watchers at this point.
671 859
672See the EV::check watcher, below, for explanations and an example. 860See the EV::check watcher, below, for explanations and an example.
681=over 4 869=over 4
682 870
683=item $w = EV::check $callback 871=item $w = EV::check $callback
684 872
685=item $w = EV::check_ns $callback 873=item $w = EV::check_ns $callback
874
875=item $w = $loop->check ($callback)
876
877=item $w = $loop->check_ns ($callback)
686 878
687Call the callback just after the process wakes up again (after it has 879Call the callback just after the process wakes up again (after it has
688gathered events), but before any other callbacks have been invoked. 880gathered events), but before any other callbacks have been invoked.
689 881
690This is used to integrate other event-based software into the EV 882This is used to integrate other event-based software into the EV
700 or return; 892 or return;
701 893
702 # make the dispatcher handle any outstanding stuff 894 # make the dispatcher handle any outstanding stuff
703 ... not shown 895 ... not shown
704 896
705 # create an IO watcher for each and every socket 897 # create an I/O watcher for each and every socket
706 @snmp_watcher = ( 898 @snmp_watcher = (
707 (map { EV::io $_, EV::READ, sub { } } 899 (map { EV::io $_, EV::READ, sub { } }
708 keys %{ $dispatcher->{_descriptors} }), 900 keys %{ $dispatcher->{_descriptors} }),
709 901
710 EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] 902 EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
745 937
746=item $w = EV::fork $callback 938=item $w = EV::fork $callback
747 939
748=item $w = EV::fork_ns $callback 940=item $w = EV::fork_ns $callback
749 941
942=item $w = $loop->fork ($callback)
943
944=item $w = $loop->fork_ns ($callback)
945
750Call the callback before the event loop is resumed in the child process 946Call the callback before the event loop is resumed in the child process
751after a fork. 947after a fork.
752 948
753The C<fork_ns> variant doesn't start (activate) the newly created watcher. 949The C<fork_ns> variant doesn't start (activate) the newly created watcher.
950
951=back
952
953
954=head3 EMBED WATCHERS - when one backend isn't enough...
955
956This is a rather advanced watcher type that lets you embed one event loop
957into another (currently only IO events are supported in the embedded
958loop, other types of watchers might be handled in a delayed or incorrect
959fashion and must not be used).
960
961See the libev documentation at
962L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
963(locally installed as F<EV::c_doc>) for more details.
964
965In short, this watcher is most useful on BSD systems without working
966kqueue to still be able to handle a large number of sockets:
967
968 my $socket_loop;
969
970 # check wether we use SELECT or POLL _and_ KQUEUE is supported
971 if (
972 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
973 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
974 ) {
975 # use kqueue for sockets
976 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
977 }
978
979 # use the default loop otherwise
980 $socket_loop ||= EV::default_loop;
981
982=over 4
983
984=item $w = EV::embed $otherloop[, $callback]
985
986=item $w = EV::embed_ns $otherloop[, $callback]
987
988=item $w = $loop->embed ($otherloop[, $callback])
989
990=item $w = $loop->embed_ns ($otherloop[, $callback])
991
992Call the callback when the embedded event loop (C<$otherloop>) has any
993I/O activity. The C<$callback> is optional: if it is missing, then the
994embedded event loop will be managed automatically (which is recommended),
995otherwise you have to invoke C<sweep> yourself.
996
997The C<embed_ns> variant doesn't start (activate) the newly created watcher.
998
999=back
1000
1001=head3 ASYNC WATCHERS - how to wake up another event loop
1002
1003Async watchers are provided by EV, but have little use in perl directly, as perl
1004neither supports threads nor direct access to signal handlers or other
1005contexts where they could be of value.
1006
1007It is, however, possible to use them from the XS level.
1008
1009Please see the libev documentation for further details.
1010
1011=over 4
1012
1013=item $w = EV::async $callback
1014
1015=item $w = EV::async_ns $callback
1016
1017=item $w->send
1018
1019=item $bool = $w->async_pending
754 1020
755=back 1021=back
756 1022
757 1023
758=head1 PERL SIGNALS 1024=head1 PERL SIGNALS
769to be called on every event loop iteration by installing a C<EV::check> 1035to be called on every event loop iteration by installing a C<EV::check>
770watcher: 1036watcher:
771 1037
772 my $async_check = EV::check sub { }; 1038 my $async_check = EV::check sub { };
773 1039
774This ensures that perl shortly gets into control for a short time, and 1040This ensures that perl gets into control for a short time to handle any
775also ensures slower overall operation. 1041pending signals, and also ensures (slightly) slower overall operation.
776 1042
777=head1 THREADS 1043=head1 THREADS
778 1044
779Threads are not supported by this module in any way. Perl pseudo-threads 1045Threads are not supported by this module in any way. Perl pseudo-threads
780is evil stuff and must die. As soon as Perl gains real threads I will work 1046is evil stuff and must die. As soon as Perl gains real threads I will work
802our $DIED = sub { 1068our $DIED = sub {
803 warn "EV: error in callback (ignoring): $@"; 1069 warn "EV: error in callback (ignoring): $@";
804}; 1070};
805 1071
806default_loop 1072default_loop
807 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; 1073 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
808 1074
8091; 10751;
810 1076
811=head1 SEE ALSO 1077=head1 SEE ALSO
812 1078
813L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as 1079L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
814event loop), L<Coro::EV> (efficient coroutines with EV). 1080event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
1081coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1082event-loop agnostic and portable event driven programming.
815 1083
816=head1 AUTHOR 1084=head1 AUTHOR
817 1085
818 Marc Lehmann <schmorp@schmorp.de> 1086 Marc Lehmann <schmorp@schmorp.de>
819 http://home.schmorp.de/ 1087 http://home.schmorp.de/
820 1088
821=cut 1089=cut
822 1090

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