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Revision 1.55 by root, Tue Nov 27 08:11:52 2007 UTC vs.
Revision 1.128 by root, Thu Oct 21 02:46:59 2010 UTC

2 2
3EV - perl interface to libev, a high performance full-featured event loop 3EV - perl interface to libev, a high performance full-featured event loop
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use EV; 7 use EV;
8
9 # TIMERS
10
11 my $w = EV::timer 2, 0, sub {
12 warn "is called after 2s";
13 };
14
15 my $w = EV::timer 2, 2, sub {
16 warn "is called roughly every 2s (repeat = 2)";
17 };
18
19 undef $w; # destroy event watcher again
20
21 my $w = EV::periodic 0, 60, 0, sub {
22 warn "is called every minute, on the minute, exactly";
23 };
24
25 # IO
26
27 my $w = EV::io *STDIN, EV::READ, sub {
28 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29 warn "stdin is readable, you entered: ", <STDIN>;
30 };
31
32 # SIGNALS
33
34 my $w = EV::signal 'QUIT', sub {
35 warn "sigquit received\n";
36 };
37
38 # CHILD/PID STATUS CHANGES
8 39
9 # TIMERS 40 my $w = EV::child 666, 0, sub {
41 my ($w, $revents) = @_;
42 my $status = $w->rstatus;
43 };
10 44
11 my $w = EV::timer 2, 0, sub {
12 warn "is called after 2s";
13 };
14
15 my $w = EV::timer 2, 2, sub {
16 warn "is called roughly every 2s (repeat = 2)";
17 };
18
19 undef $w; # destroy event watcher again
20
21 my $w = EV::periodic 0, 60, 0, sub {
22 warn "is called every minute, on the minute, exactly";
23 };
24
25 # IO
26
27 my $w = EV::io *STDIN, EV::READ, sub {
28 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29 warn "stdin is readable, you entered: ", <STDIN>;
30 };
31
32 # SIGNALS
33
34 my $w = EV::signal 'QUIT', sub {
35 warn "sigquit received\n";
36 };
37
38 # CHILD/PID STATUS CHANGES
39
40 my $w = EV::child 666, sub {
41 my ($w, $revents) = @_;
42 my $status = $w->rstatus;
43 };
44
45 # STAT CHANGES 45 # STAT CHANGES
46 my $w = EV::stat "/etc/passwd", 10, sub { 46 my $w = EV::stat "/etc/passwd", 10, sub {
47 my ($w, $revents) = @_; 47 my ($w, $revents) = @_;
48 warn $w->path, " has changed somehow.\n"; 48 warn $w->path, " has changed somehow.\n";
49 }; 49 };
50 50
51 # MAINLOOP 51 # MAINLOOP
52 EV::loop; # loop until EV::unloop is called or all watchers stop 52 EV::loop; # loop until EV::unloop is called or all watchers stop
53 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled 53 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
54 EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block 54 EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
55
56=head1 BEFORE YOU START USING THIS MODULE
57
58If you only need timer, I/O, signal, child and idle watchers and not the
59advanced functionality of this module, consider using L<AnyEvent> instead,
60specifically the simplified API described in L<AE>.
61
62When used with EV as backend, the L<AE> API is as fast as the native L<EV>
63API, but your programs/modules will still run with many other event loops.
55 64
56=head1 DESCRIPTION 65=head1 DESCRIPTION
57 66
58This module provides an interface to libev 67This module provides an interface to libev
59(L<http://software.schmorp.de/pkg/libev.html>). While the documentation 68(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
60below is comprehensive, one might also consult the documentation of libev 69below is comprehensive, one might also consult the documentation of
61itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on 70libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
62watcher semantics or some discussion on the available backends, or how to 71F<perldoc EV::libev>) for more subtle details on watcher semantics or some
63force a specific backend with C<LIBEV_FLAGS>. 72discussion on the available backends, or how to force a specific backend
73with C<LIBEV_FLAGS>, or just about in any case because it has much more
74detailed information.
75
76This module is very fast and scalable. It is actually so fast that you
77can use it through the L<AnyEvent> module, stay portable to other event
78loops (if you don't rely on any watcher types not available through it)
79and still be faster than with any other event loop currently supported in
80Perl.
81
82=head2 MODULE EXPORTS
83
84This module does not export any symbols.
64 85
65=cut 86=cut
66 87
67package EV; 88package EV;
68 89
69use strict; 90use common::sense;
70 91
71BEGIN { 92BEGIN {
72 our $VERSION = '1.4'; 93 our $VERSION = '4.00';
73 use XSLoader; 94 use XSLoader;
74 XSLoader::load "EV", $VERSION; 95 XSLoader::load "EV", $VERSION;
75} 96}
76 97
77@EV::IO::ISA = 98@EV::IO::ISA =
78@EV::Timer::ISA = 99@EV::Timer::ISA =
79@EV::Periodic::ISA = 100@EV::Periodic::ISA =
80@EV::Signal::ISA = 101@EV::Signal::ISA =
102@EV::Child::ISA =
103@EV::Stat::ISA =
81@EV::Idle::ISA = 104@EV::Idle::ISA =
82@EV::Prepare::ISA = 105@EV::Prepare::ISA =
83@EV::Check::ISA = 106@EV::Check::ISA =
84@EV::Child::ISA =
85@EV::Embed::ISA = 107@EV::Embed::ISA =
86@EV::Stat::ISA = "EV::Watcher"; 108@EV::Fork::ISA =
109@EV::Async::ISA =
110 "EV::Watcher";
111
112@EV::Loop::Default::ISA = "EV::Loop";
113
114=head1 EVENT LOOPS
115
116EV supports multiple event loops: There is a single "default event loop"
117that can handle everything including signals and child watchers, and any
118number of "dynamic event loops" that can use different backends (with
119various limitations), but no child and signal watchers.
120
121You do not have to do anything to create the default event loop: When
122the module is loaded a suitable backend is selected on the premise of
123selecting a working backend (which for example rules out kqueue on most
124BSDs). Modules should, unless they have "special needs" always use the
125default loop as this is fastest (perl-wise), best supported by other
126modules (e.g. AnyEvent or Coro) and most portable event loop.
127
128For specific programs you can create additional event loops dynamically.
129
130If you want to take advantage of kqueue (which often works properly for
131sockets only) even though the default loop doesn't enable it, you can
132I<embed> a kqueue loop into the default loop: running the default loop
133will then also service the kqueue loop to some extent. See the example in
134the section about embed watchers for an example on how to achieve that.
135
136=over 4
137
138=item $loop = new EV::Loop [$flags]
139
140Create a new event loop as per the specified flags. Please refer to
141the C<ev_loop_new ()> function description in the libev documentation
142(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
143or locally-installed as F<EV::libev> manpage) for more info.
144
145The loop will automatically be destroyed when it is no longer referenced
146by any watcher and the loop object goes out of scope.
147
148If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
149is recommended, as only the default event loop is protected by this
150module. If you I<are> embedding this loop in the default loop, this is not
151necessary, as C<EV::embed> automatically does the right thing on fork.
152
153=item $loop->loop_fork
154
155Must be called after a fork in the child, before entering or continuing
156the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
157this function automatically, at some performance loss (refer to the libev
158documentation).
159
160=item $loop->loop_verify
161
162Calls C<ev_verify> to make internal consistency checks (for debugging
163libev) and abort the program if any data structures were found to be
164corrupted.
165
166=item $loop = EV::default_loop [$flags]
167
168Return the default loop (which is a singleton object). Since this module
169already creates the default loop with default flags, specifying flags here
170will not have any effect unless you destroy the default loop first, which
171isn't supported. So in short: don't do it, and if you break it, you get to
172keep the pieces.
173
174=back
175
87 176
88=head1 BASIC INTERFACE 177=head1 BASIC INTERFACE
89 178
90=over 4 179=over 4
91 180
92=item $EV::DIED 181=item $EV::DIED
93 182
94Must contain a reference to a function that is called when a callback 183Must contain a reference to a function that is called when a callback
95throws an exception (with $@ containing thr error). The default prints an 184throws an exception (with $@ containing the error). The default prints an
96informative message and continues. 185informative message and continues.
97 186
98If this callback throws an exception it will be silently ignored. 187If this callback throws an exception it will be silently ignored.
99 188
189=item $flags = EV::supported_backends
190
191=item $flags = EV::recommended_backends
192
193=item $flags = EV::embeddable_backends
194
195Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
196instance of EV, the set of recommended backends (supposed to be good) for
197this platform and the set of embeddable backends (see EMBED WATCHERS).
198
199=item EV::sleep $seconds
200
201Block the process for the given number of (fractional) seconds.
202
100=item $time = EV::time 203=item $time = EV::time
101 204
102Returns the current time in (fractional) seconds since the epoch. 205Returns the current time in (fractional) seconds since the epoch.
103 206
104=item $time = EV::now 207=item $time = EV::now
105 208
209=item $time = $loop->now
210
106Returns the time the last event loop iteration has been started. This 211Returns the time the last event loop iteration has been started. This
107is the time that (relative) timers are based on, and refering to it is 212is the time that (relative) timers are based on, and referring to it is
108usually faster then calling EV::time. 213usually faster then calling EV::time.
109 214
110=item $method = EV::method 215=item EV::now_update
111 216
217=item $loop->now_update
218
219Establishes the current time by querying the kernel, updating the time
220returned by C<EV::now> in the progress. This is a costly operation and
221is usually done automatically within C<EV::loop>.
222
223This function is rarely useful, but when some event callback runs for a
224very long time without entering the event loop, updating libev's idea of
225the current time is a good idea.
226
227=item EV::suspend
228
229=item $loop->suspend
230
231=item EV::resume
232
233=item $loop->resume
234
235These two functions suspend and resume a loop, for use when the loop is
236not used for a while and timeouts should not be processed.
237
238A typical use case would be an interactive program such as a game: When
239the user presses C<^Z> to suspend the game and resumes it an hour later it
240would be best to handle timeouts as if no time had actually passed while
241the program was suspended. This can be achieved by calling C<suspend>
242in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
243C<resume> directly afterwards to resume timer processing.
244
245Effectively, all C<timer> watchers will be delayed by the time spend
246between C<suspend> and C<resume>, and all C<periodic> watchers
247will be rescheduled (that is, they will lose any events that would have
248occured while suspended).
249
250After calling C<suspend> you B<must not> call I<any> function on the given
251loop other than C<resume>, and you B<must not> call C<resume>
252without a previous call to C<suspend>.
253
254Calling C<suspend>/C<resume> has the side effect of updating the event
255loop time (see C<now_update>).
256
257=item $backend = EV::backend
258
259=item $backend = $loop->backend
260
112Returns an integer describing the backend used by libev (EV::METHOD_SELECT 261Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
113or EV::METHOD_EPOLL). 262or EV::BACKEND_EPOLL).
114 263
115=item EV::loop [$flags] 264=item EV::loop [$flags]
265
266=item $loop->loop ([$flags])
116 267
117Begin checking for events and calling callbacks. It returns when a 268Begin checking for events and calling callbacks. It returns when a
118callback calls EV::unloop. 269callback calls EV::unloop.
119 270
120The $flags argument can be one of the following: 271The $flags argument can be one of the following:
123 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 274 EV::LOOP_ONESHOT block at most once (wait, but do not loop)
124 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 275 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
125 276
126=item EV::unloop [$how] 277=item EV::unloop [$how]
127 278
279=item $loop->unloop ([$how])
280
128When called with no arguments or an argument of EV::UNLOOP_ONE, makes the 281When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
129innermost call to EV::loop return. 282innermost call to EV::loop return.
130 283
131When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as 284When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
132fast as possible. 285fast as possible.
133 286
287=item $count = EV::loop_count
288
289=item $count = $loop->loop_count
290
291Return the number of times the event loop has polled for new
292events. Sometimes useful as a generation counter.
293
134=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 294=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
295
296=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
135 297
136This function rolls together an I/O and a timer watcher for a single 298This function rolls together an I/O and a timer watcher for a single
137one-shot event without the need for managing a watcher object. 299one-shot event without the need for managing a watcher object.
138 300
139If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> 301If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
145If timeout is C<undef> or negative, then there will be no 307If timeout is C<undef> or negative, then there will be no
146timeout. Otherwise a EV::timer with this value will be started. 308timeout. Otherwise a EV::timer with this value will be started.
147 309
148When an error occurs or either the timeout or I/O watcher triggers, then 310When an error occurs or either the timeout or I/O watcher triggers, then
149the callback will be called with the received event set (in general 311the callback will be called with the received event set (in general
150you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>, 312you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
151C<EV::WRITE> and C<EV::TIMEOUT>). 313C<EV::WRITE> and C<EV::TIMER>).
152 314
153EV::once doesn't return anything: the watchers stay active till either 315EV::once doesn't return anything: the watchers stay active till either
154of them triggers, then they will be stopped and freed, and the callback 316of them triggers, then they will be stopped and freed, and the callback
155invoked. 317invoked.
156 318
157=back 319=item EV::feed_fd_event ($fd, $revents)
158 320
321=item $loop->feed_fd_event ($fd, $revents)
322
323Feed an event on a file descriptor into EV. EV will react to this call as
324if the readyness notifications specified by C<$revents> (a combination of
325C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
326
327=item EV::feed_signal_event ($signal)
328
329Feed a signal event into EV. EV will react to this call as if the signal
330specified by C<$signal> had occured.
331
332=item EV::set_io_collect_interval $time
333
334=item $loop->set_io_collect_interval ($time)
335
336=item EV::set_timeout_collect_interval $time
337
338=item $loop->set_timeout_collect_interval ($time)
339
340These advanced functions set the minimum block interval when polling for I/O events and the minimum
341wait interval for timer events. See the libev documentation at
342L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
343(locally installed as F<EV::libev>) for a more detailed discussion.
344
345=item $count = EV::pending_count
346
347=item $count = $loop->pending_count
348
349Returns the number of currently pending watchers.
350
351=item EV::invoke_pending
352
353=item $loop->invoke_pending
354
355Invoke all currently pending watchers.
356
357=back
358
359
159=head2 WATCHER OBJECTS 360=head1 WATCHER OBJECTS
160 361
161A watcher is an object that gets created to record your interest in some 362A watcher is an object that gets created to record your interest in some
162event. For instance, if you want to wait for STDIN to become readable, you 363event. For instance, if you want to wait for STDIN to become readable, you
163would create an EV::io watcher for that: 364would create an EV::io watcher for that:
164 365
165 my $watcher = EV::io *STDIN, EV::READ, sub { 366 my $watcher = EV::io *STDIN, EV::READ, sub {
166 my ($watcher, $revents) = @_; 367 my ($watcher, $revents) = @_;
167 warn "yeah, STDIN should not be readable without blocking!\n" 368 warn "yeah, STDIN should now be readable without blocking!\n"
168 }; 369 };
169 370
170All watchers can be active (waiting for events) or inactive (paused). Only 371All watchers can be active (waiting for events) or inactive (paused). Only
171active watchers will have their callbacks invoked. All callbacks will be 372active watchers will have their callbacks invoked. All callbacks will be
172called with at least two arguments: the watcher and a bitmask of received 373called with at least two arguments: the watcher and a bitmask of received
173events. 374events.
174 375
175Each watcher type has its associated bit in revents, so you can use the 376Each watcher type has its associated bit in revents, so you can use the
176same callback for multiple watchers. The event mask is named after the 377same callback for multiple watchers. The event mask is named after the
177type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 378type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
178EV::periodic sets EV::PERIODIC and so on, with the exception of IO events 379EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
179(which can set both EV::READ and EV::WRITE bits), and EV::timer (which 380(which can set both EV::READ and EV::WRITE bits).
180uses EV::TIMEOUT).
181 381
182In the rare case where one wants to create a watcher but not start it at 382In the rare case where one wants to create a watcher but not start it at
183the same time, each constructor has a variant with a trailing C<_ns> in 383the same time, each constructor has a variant with a trailing C<_ns> in
184its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. 384its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
185 385
205 405
206=item $w->stop 406=item $w->stop
207 407
208Stop a watcher if it is active. Also clear any pending events (events that 408Stop a watcher if it is active. Also clear any pending events (events that
209have been received but that didn't yet result in a callback invocation), 409have been received but that didn't yet result in a callback invocation),
210regardless of wether the watcher was active or not. 410regardless of whether the watcher was active or not.
211 411
212=item $bool = $w->is_active 412=item $bool = $w->is_active
213 413
214Returns true if the watcher is active, false otherwise. 414Returns true if the watcher is active, false otherwise.
215 415
245The default priority of any newly-created watcher is 0. 445The default priority of any newly-created watcher is 0.
246 446
247Note that the priority semantics have not yet been fleshed out and are 447Note that the priority semantics have not yet been fleshed out and are
248subject to almost certain change. 448subject to almost certain change.
249 449
250=item $w->trigger ($revents) 450=item $w->invoke ($revents)
251 451
252Call the callback *now* with the given event mask. 452Call the callback *now* with the given event mask.
453
454=item $w->feed_event ($revents)
455
456Feed some events on this watcher into EV. EV will react to this call as if
457the watcher had received the given C<$revents> mask.
458
459=item $revents = $w->clear_pending
460
461If the watcher is pending, this function clears its pending status and
462returns its C<$revents> bitset (as if its callback was invoked). If the
463watcher isn't pending it does nothing and returns C<0>.
253 464
254=item $previous_state = $w->keepalive ($bool) 465=item $previous_state = $w->keepalive ($bool)
255 466
256Normally, C<EV::loop> will return when there are no active watchers 467Normally, C<EV::loop> will return when there are no active watchers
257(which is a "deadlock" because no progress can be made anymore). This is 468(which is a "deadlock" because no progress can be made anymore). This is
258convinient because it allows you to start your watchers (and your jobs), 469convenient because it allows you to start your watchers (and your jobs),
259call C<EV::loop> once and when it returns you know that all your jobs are 470call C<EV::loop> once and when it returns you know that all your jobs are
260finished (or they forgot to register some watchers for their task :). 471finished (or they forgot to register some watchers for their task :).
261 472
262Sometimes, however, this gets in your way, for example when you the module 473Sometimes, however, this gets in your way, for example when the module
263that calls C<EV::loop> (usually the main program) is not the same module 474that calls C<EV::loop> (usually the main program) is not the same module
264as a long-living watcher (for example a DNS client module written by 475as a long-living watcher (for example a DNS client module written by
265somebody else even). Then you might want any outstanding requests to be 476somebody else even). Then you might want any outstanding requests to be
266handled, but you would not want to keep C<EV::loop> from returning just 477handled, but you would not want to keep C<EV::loop> from returning just
267because you happen to have this long-running UDP port watcher. 478because you happen to have this long-running UDP port watcher.
268 479
269In this case you can clear the keepalive status, which means that even 480In this case you can clear the keepalive status, which means that even
270though your watcher is active, it won't keep C<EV::loop> from returning. 481though your watcher is active, it won't keep C<EV::loop> from returning.
271 482
272The initial value for keepalive is true (enabled), and you cna change it 483The initial value for keepalive is true (enabled), and you can change it
273any time. 484any time.
274 485
275Example: Register an IO watcher for some UDP socket but do not keep the 486Example: Register an I/O watcher for some UDP socket but do not keep the
276event loop from running just because of that watcher. 487event loop from running just because of that watcher.
277 488
278 my $udp_socket = ... 489 my $udp_socket = ...
279 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 490 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
280 $udp_watcher->keepalive (0); 491 $udp_watcher->keepalive (0);
281 492
282=back 493=item $loop = $w->loop
283 494
495Return the loop that this watcher is attached to.
284 496
497=back
498
499
285=head2 WATCHER TYPES 500=head1 WATCHER TYPES
286 501
287Each of the following subsections describes a single watcher type. 502Each of the following subsections describes a single watcher type.
288 503
289=head3 IO WATCHERS - is this file descriptor readable or writable? 504=head3 I/O WATCHERS - is this file descriptor readable or writable?
290 505
291=over 4 506=over 4
292 507
293=item $w = EV::io $fileno_or_fh, $eventmask, $callback 508=item $w = EV::io $fileno_or_fh, $eventmask, $callback
294 509
295=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 510=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
511
512=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
513
514=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
296 515
297As long as the returned watcher object is alive, call the C<$callback> 516As long as the returned watcher object is alive, call the C<$callback>
298when at least one of events specified in C<$eventmask> occurs. 517when at least one of events specified in C<$eventmask> occurs.
299 518
300The $eventmask can be one or more of these constants ORed together: 519The $eventmask can be one or more of these constants ORed together:
329=over 4 548=over 4
330 549
331=item $w = EV::timer $after, $repeat, $callback 550=item $w = EV::timer $after, $repeat, $callback
332 551
333=item $w = EV::timer_ns $after, $repeat, $callback 552=item $w = EV::timer_ns $after, $repeat, $callback
553
554=item $w = $loop->timer ($after, $repeat, $callback)
555
556=item $w = $loop->timer_ns ($after, $repeat, $callback)
334 557
335Calls the callback after C<$after> seconds (which may be fractional). If 558Calls the callback after C<$after> seconds (which may be fractional). If
336C<$repeat> is non-zero, the timer will be restarted (with the $repeat 559C<$repeat> is non-zero, the timer will be restarted (with the $repeat
337value as $after) after the callback returns. 560value as $after) after the callback returns.
338 561
379=over 4 602=over 4
380 603
381=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback 604=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
382 605
383=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 606=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
607
608=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
609
610=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
384 611
385Similar to EV::timer, but is not based on relative timeouts but on 612Similar to EV::timer, but is not based on relative timeouts but on
386absolute times. Apart from creating "simple" timers that trigger "at" the 613absolute times. Apart from creating "simple" timers that trigger "at" the
387specified time, it can also be used for non-drifting absolute timers and 614specified time, it can also be used for non-drifting absolute timers and
388more complex, cron-like, setups that are not adversely affected by time 615more complex, cron-like, setups that are not adversely affected by time
398This time simply fires at the wallclock time C<$at> and doesn't repeat. It 625This time simply fires at the wallclock time C<$at> and doesn't repeat. It
399will not adjust when a time jump occurs, that is, if it is to be run 626will not adjust when a time jump occurs, that is, if it is to be run
400at January 1st 2011 then it will run when the system time reaches or 627at January 1st 2011 then it will run when the system time reaches or
401surpasses this time. 628surpasses this time.
402 629
403=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 630=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
404 631
405In this mode the watcher will always be scheduled to time out at the 632In this mode the watcher will always be scheduled to time out at the
406next C<$at + N * $interval> time (for some integer N) and then repeat, 633next C<$at + N * $interval> time (for some integer N) and then repeat,
407regardless of any time jumps. 634regardless of any time jumps.
408 635
426time the periodic watcher gets scheduled, the reschedule callback 653time the periodic watcher gets scheduled, the reschedule callback
427($reschedule_cb) will be called with the watcher as first, and the current 654($reschedule_cb) will be called with the watcher as first, and the current
428time as second argument. 655time as second argument.
429 656
430I<This callback MUST NOT stop or destroy this or any other periodic 657I<This callback MUST NOT stop or destroy this or any other periodic
431watcher, ever>. If you need to stop it, return 1e30 and stop it 658watcher, ever, and MUST NOT call any event loop functions or methods>. If
432afterwards. 659you need to stop it, return 1e30 and stop it afterwards. You may create
660and start a C<EV::prepare> watcher for this task.
433 661
434It must return the next time to trigger, based on the passed time value 662It must return the next time to trigger, based on the passed time value
435(that is, the lowest time value larger than to the second argument). It 663(that is, the lowest time value larger than or equal to to the second
436will usually be called just before the callback will be triggered, but 664argument). It will usually be called just before the callback will be
437might be called at other times, too. 665triggered, but might be called at other times, too.
438 666
439This can be used to create very complex timers, such as a timer that 667This can be used to create very complex timers, such as a timer that
440triggers on each midnight, local time (actually 24 hours after the last 668triggers on each midnight, local time (actually 24 hours after the last
441midnight, to keep the example simple. If you know a way to do it correctly 669midnight, to keep the example simple. If you know a way to do it correctly
442in about the same space (without requiring elaborate modules), drop me a 670in about the same space (without requiring elaborate modules), drop me a
463 691
464=item $w->again 692=item $w->again
465 693
466Simply stops and starts the watcher again. 694Simply stops and starts the watcher again.
467 695
696=item $time = $w->at
697
698Return the time that the watcher is expected to trigger next.
699
468=back 700=back
469 701
470 702
471=head3 SIGNAL WATCHERS - signal me when a signal gets signalled! 703=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
472 704
473=over 4 705=over 4
474 706
475=item $w = EV::signal $signal, $callback 707=item $w = EV::signal $signal, $callback
476 708
477=item $w = EV::signal_ns $signal, $callback 709=item $w = EV::signal_ns $signal, $callback
710
711=item $w = $loop->signal ($signal, $callback)
712
713=item $w = $loop->signal_ns ($signal, $callback)
478 714
479Call the callback when $signal is received (the signal can be specified by 715Call the callback when $signal is received (the signal can be specified by
480number or by name, just as with C<kill> or C<%SIG>). 716number or by name, just as with C<kill> or C<%SIG>).
717
718Only one event loop can grab a given signal - attempting to grab the same
719signal from two EV loops will crash the program immediately or cause data
720corruption.
481 721
482EV will grab the signal for the process (the kernel only allows one 722EV will grab the signal for the process (the kernel only allows one
483component to receive a signal at a time) when you start a signal watcher, 723component to receive a signal at a time) when you start a signal watcher,
484and removes it again when you stop it. Perl does the same when you 724and removes it again when you stop it. Perl does the same when you
485add/remove callbacks to C<%SIG>, so watch out. 725add/remove callbacks to C<%SIG>, so watch out.
505 745
506=head3 CHILD WATCHERS - watch out for process status changes 746=head3 CHILD WATCHERS - watch out for process status changes
507 747
508=over 4 748=over 4
509 749
510=item $w = EV::child $pid, $callback 750=item $w = EV::child $pid, $trace, $callback
511 751
512=item $w = EV::child_ns $pid, $callback 752=item $w = EV::child_ns $pid, $trace, $callback
513 753
754=item $w = $loop->child ($pid, $trace, $callback)
755
756=item $w = $loop->child_ns ($pid, $trace, $callback)
757
514Call the callback when a status change for pid C<$pid> (or any pid if 758Call the callback when a status change for pid C<$pid> (or any pid
515C<$pid> is 0) has been received. More precisely: when the process receives 759if C<$pid> is 0) has been received (a status change happens when the
760process terminates or is killed, or, when trace is true, additionally when
761it is stopped or continued). More precisely: when the process receives
516a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all 762a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
517changed/zombie children and call the callback. 763changed/zombie children and call the callback.
518 764
519It is valid (and fully supported) to install a child watcher after a child 765It is valid (and fully supported) to install a child watcher after a child
520has exited but before the event loop has started its next iteration (for 766has exited but before the event loop has started its next iteration (for
527You can have as many pid watchers per pid as you want, they will all be 773You can have as many pid watchers per pid as you want, they will all be
528called. 774called.
529 775
530The C<child_ns> variant doesn't start (activate) the newly created watcher. 776The C<child_ns> variant doesn't start (activate) the newly created watcher.
531 777
532=item $w->set ($pid) 778=item $w->set ($pid, $trace)
533 779
534Reconfigures the watcher, see the constructor above for details. Can be called at 780Reconfigures the watcher, see the constructor above for details. Can be called at
535any time. 781any time.
536 782
537=item $current_pid = $w->pid 783=item $current_pid = $w->pid
538 784
539=item $old_pid = $w->pid ($new_pid)
540
541Returns the previously set process id and optionally set a new one. 785Returns the previously set process id and optionally set a new one.
542 786
543=item $exit_status = $w->rstatus 787=item $exit_status = $w->rstatus
544 788
545Return the exit/wait status (as returned by waitpid, see the waitpid entry 789Return the exit/wait status (as returned by waitpid, see the waitpid entry
551watcher for all pids). 795watcher for all pids).
552 796
553=back 797=back
554 798
555 799
800=head3 STAT WATCHERS - did the file attributes just change?
801
802=over 4
803
804=item $w = EV::stat $path, $interval, $callback
805
806=item $w = EV::stat_ns $path, $interval, $callback
807
808=item $w = $loop->stat ($path, $interval, $callback)
809
810=item $w = $loop->stat_ns ($path, $interval, $callback)
811
812Call the callback when a file status change has been detected on
813C<$path>. The C<$path> does not need to exist, changing from "path exists"
814to "path does not exist" is a status change like any other.
815
816The C<$interval> is a recommended polling interval for systems where
817OS-supported change notifications don't exist or are not supported. If
818you use C<0> then an unspecified default is used (which is highly
819recommended!), which is to be expected to be around five seconds usually.
820
821This watcher type is not meant for massive numbers of stat watchers,
822as even with OS-supported change notifications, this can be
823resource-intensive.
824
825The C<stat_ns> variant doesn't start (activate) the newly created watcher.
826
827=item ... = $w->stat
828
829This call is very similar to the perl C<stat> built-in: It stats (using
830C<lstat>) the path specified in the watcher and sets perls stat cache (as
831well as EV's idea of the current stat values) to the values found.
832
833In scalar context, a boolean is return indicating success or failure of
834the stat. In list context, the same 13-value list as with stat is returned
835(except that the blksize and blocks fields are not reliable).
836
837In the case of an error, errno is set to C<ENOENT> (regardless of the
838actual error value) and the C<nlink> value is forced to zero (if the stat
839was successful then nlink is guaranteed to be non-zero).
840
841See also the next two entries for more info.
842
843=item ... = $w->attr
844
845Just like C<< $w->stat >>, but without the initial stat'ing: this returns
846the values most recently detected by EV. See the next entry for more info.
847
848=item ... = $w->prev
849
850Just like C<< $w->stat >>, but without the initial stat'ing: this returns
851the previous set of values, before the change.
852
853That is, when the watcher callback is invoked, C<< $w->prev >> will be set
854to the values found I<before> a change was detected, while C<< $w->attr >>
855returns the values found leading to the change detection. The difference (if any)
856between C<prev> and C<attr> is what triggered the callback.
857
858If you did something to the filesystem object and do not want to trigger
859yet another change, you can call C<stat> to update EV's idea of what the
860current attributes are.
861
862=item $w->set ($path, $interval)
863
864Reconfigures the watcher, see the constructor above for details. Can be
865called at any time.
866
867=item $current_path = $w->path
868
869=item $old_path = $w->path ($new_path)
870
871Returns the previously set path and optionally set a new one.
872
873=item $current_interval = $w->interval
874
875=item $old_interval = $w->interval ($new_interval)
876
877Returns the previously set interval and optionally set a new one. Can be
878used to query the actual interval used.
879
880=back
881
882
556=head3 IDLE WATCHERS - when you've got nothing better to do... 883=head3 IDLE WATCHERS - when you've got nothing better to do...
557 884
558=over 4 885=over 4
559 886
560=item $w = EV::idle $callback 887=item $w = EV::idle $callback
561 888
562=item $w = EV::idle_ns $callback 889=item $w = EV::idle_ns $callback
563 890
564Call the callback when there are no pending io, timer/periodic, signal or 891=item $w = $loop->idle ($callback)
565child events, i.e. when the process is idle. 892
893=item $w = $loop->idle_ns ($callback)
894
895Call the callback when there are no other pending watchers of the same or
896higher priority (excluding check, prepare and other idle watchers of the
897same or lower priority, of course). They are called idle watchers because
898when the watcher is the highest priority pending event in the process, the
899process is considered to be idle at that priority.
900
901If you want a watcher that is only ever called when I<no> other events are
902outstanding you have to set the priority to C<EV::MINPRI>.
566 903
567The process will not block as long as any idle watchers are active, and 904The process will not block as long as any idle watchers are active, and
568they will be called repeatedly until stopped. 905they will be called repeatedly until stopped.
569 906
907For example, if you have idle watchers at priority C<0> and C<1>, and
908an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
909and the I/O watcher will always run when ready. Only when the idle watcher
910at priority C<1> is stopped and the I/O watcher at priority C<0> is not
911pending with the C<0>-priority idle watcher be invoked.
912
570The C<idle_ns> variant doesn't start (activate) the newly created watcher. 913The C<idle_ns> variant doesn't start (activate) the newly created watcher.
571 914
572=back 915=back
573 916
574 917
577=over 4 920=over 4
578 921
579=item $w = EV::prepare $callback 922=item $w = EV::prepare $callback
580 923
581=item $w = EV::prepare_ns $callback 924=item $w = EV::prepare_ns $callback
925
926=item $w = $loop->prepare ($callback)
927
928=item $w = $loop->prepare_ns ($callback)
582 929
583Call the callback just before the process would block. You can still 930Call the callback just before the process would block. You can still
584create/modify any watchers at this point. 931create/modify any watchers at this point.
585 932
586See the EV::check watcher, below, for explanations and an example. 933See the EV::check watcher, below, for explanations and an example.
596 943
597=item $w = EV::check $callback 944=item $w = EV::check $callback
598 945
599=item $w = EV::check_ns $callback 946=item $w = EV::check_ns $callback
600 947
948=item $w = $loop->check ($callback)
949
950=item $w = $loop->check_ns ($callback)
951
601Call the callback just after the process wakes up again (after it has 952Call the callback just after the process wakes up again (after it has
602gathered events), but before any other callbacks have been invoked. 953gathered events), but before any other callbacks have been invoked.
603 954
604This is used to integrate other event-based software into the EV 955This can be used to integrate other event-based software into the EV
605mainloop: You register a prepare callback and in there, you create io and 956mainloop: You register a prepare callback and in there, you create io and
606timer watchers as required by the other software. Here is a real-world 957timer watchers as required by the other software. Here is a real-world
607example of integrating Net::SNMP (with some details left out): 958example of integrating Net::SNMP (with some details left out):
608 959
609 our @snmp_watcher; 960 our @snmp_watcher;
614 or return; 965 or return;
615 966
616 # make the dispatcher handle any outstanding stuff 967 # make the dispatcher handle any outstanding stuff
617 ... not shown 968 ... not shown
618 969
619 # create an IO watcher for each and every socket 970 # create an I/O watcher for each and every socket
620 @snmp_watcher = ( 971 @snmp_watcher = (
621 (map { EV::io $_, EV::READ, sub { } } 972 (map { EV::io $_, EV::READ, sub { } }
622 keys %{ $dispatcher->{_descriptors} }), 973 keys %{ $dispatcher->{_descriptors} }),
623 974
624 EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] 975 EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
639 # make the dispatcher handle any new stuff 990 # make the dispatcher handle any new stuff
640 ... not shown 991 ... not shown
641 }; 992 };
642 993
643The callbacks of the created watchers will not be called as the watchers 994The callbacks of the created watchers will not be called as the watchers
644are destroyed before this cna happen (remember EV::check gets called 995are destroyed before this can happen (remember EV::check gets called
645first). 996first).
646 997
647The C<check_ns> variant doesn't start (activate) the newly created watcher. 998The C<check_ns> variant doesn't start (activate) the newly created watcher.
648 999
649=back 1000=item EV::CHECK constant issues
650 1001
651=head3 STAT WATCHERS - did the file attributes just change? 1002Like all other watcher types, there is a bitmask constant for use in
1003C<$revents> and other places. The C<EV::CHECK> is special as it has
1004the same name as the C<CHECK> sub called by Perl. This doesn't cause
1005big issues on newer perls (beginning with 5.8.9), but it means thatthe
1006constant must be I<inlined>, i.e. runtime calls will not work. That means
1007that as long as you always C<use EV> and then C<EV::CHECK> you are on the
1008safe side.
652 1009
653=over 4 1010=back
654 1011
655=item $w = EV::stat $path, $interval, $callback
656 1012
657=item $w = EV::stat_ns $path, $interval, $callback 1013=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
658 1014
659Call the callback when a file status change has been detected on 1015Fork watchers are called when a C<fork ()> was detected. The invocation
660C<$path>. The C<$path> does not need to exist, changing from "path exists" 1016is done before the event loop blocks next and before C<check> watchers
661to "path does not exist" is a status change like any other. 1017are being called, and only in the child after the fork.
662 1018
663The C<$interval> is a recommended polling interval for systems where 1019=over 4
664OS-supported change notifications don't exist or are not supported. If
665you use C<0> then an unspecified default is used (which is highly
666recommended!), which is to be expected to be around five seconds usually.
667 1020
668This watcher type is not meant for massive numbers of stat watchers, 1021=item $w = EV::fork $callback
669as even with OS-supported change notifications, this can be
670resource-intensive.
671 1022
1023=item $w = EV::fork_ns $callback
1024
1025=item $w = $loop->fork ($callback)
1026
1027=item $w = $loop->fork_ns ($callback)
1028
1029Call the callback before the event loop is resumed in the child process
1030after a fork.
1031
672The C<stat_ns> variant doesn't start (activate) the newly created watcher. 1032The C<fork_ns> variant doesn't start (activate) the newly created watcher.
673 1033
674=item $w->set ($path, $interval)
675
676Reconfigures the watcher, see the constructor above for details. Can be
677called at any time.
678
679=item $current_path = $w->path
680
681=item $old_path = $w->path ($new_path)
682
683Returns the previously set path and optionally set a new one.
684
685=item $current_interval = $w->interval
686
687=item $old_interval = $w->interval ($new_interval)
688
689Returns the previously set interval and optionally set a new one. Can be
690used to query the actual interval used.
691
692=back 1034=back
693 1035
694 1036
1037=head3 EMBED WATCHERS - when one backend isn't enough...
1038
1039This is a rather advanced watcher type that lets you embed one event loop
1040into another (currently only IO events are supported in the embedded
1041loop, other types of watchers might be handled in a delayed or incorrect
1042fashion and must not be used).
1043
1044See the libev documentation at
1045L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
1046(locally installed as F<EV::libev>) for more details.
1047
1048In short, this watcher is most useful on BSD systems without working
1049kqueue to still be able to handle a large number of sockets:
1050
1051 my $socket_loop;
1052
1053 # check wether we use SELECT or POLL _and_ KQUEUE is supported
1054 if (
1055 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
1056 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
1057 ) {
1058 # use kqueue for sockets
1059 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
1060 }
1061
1062 # use the default loop otherwise
1063 $socket_loop ||= EV::default_loop;
1064
1065=over 4
1066
1067=item $w = EV::embed $otherloop[, $callback]
1068
1069=item $w = EV::embed_ns $otherloop[, $callback]
1070
1071=item $w = $loop->embed ($otherloop[, $callback])
1072
1073=item $w = $loop->embed_ns ($otherloop[, $callback])
1074
1075Call the callback when the embedded event loop (C<$otherloop>) has any
1076I/O activity. The C<$callback> is optional: if it is missing, then the
1077embedded event loop will be managed automatically (which is recommended),
1078otherwise you have to invoke C<sweep> yourself.
1079
1080The C<embed_ns> variant doesn't start (activate) the newly created watcher.
1081
1082=back
1083
1084=head3 ASYNC WATCHERS - how to wake up another event loop
1085
1086Async watchers are provided by EV, but have little use in perl directly,
1087as perl neither supports threads running in parallel nor direct access to
1088signal handlers or other contexts where they could be of value.
1089
1090It is, however, possible to use them from the XS level.
1091
1092Please see the libev documentation for further details.
1093
1094=over 4
1095
1096=item $w = EV::async $callback
1097
1098=item $w = EV::async_ns $callback
1099
1100=item $w->send
1101
1102=item $bool = $w->async_pending
1103
1104=back
1105
1106
1107=head1 PERL SIGNALS
1108
1109While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
1110with EV is as the same as any other C library: Perl-signals will only be
1111handled when Perl runs, which means your signal handler might be invoked
1112only the next time an event callback is invoked.
1113
1114The solution is to use EV signal watchers (see C<EV::signal>), which will
1115ensure proper operations with regards to other event watchers.
1116
1117If you cannot do this for whatever reason, you can also force a watcher
1118to be called on every event loop iteration by installing a C<EV::check>
1119watcher:
1120
1121 my $async_check = EV::check sub { };
1122
1123This ensures that perl gets into control for a short time to handle any
1124pending signals, and also ensures (slightly) slower overall operation.
1125
695=head1 THREADS 1126=head1 ITHREADS
696 1127
697Threads are not supported by this module in any way. Perl pseudo-threads 1128Ithreads are not supported by this module in any way. Perl pseudo-threads
698is evil stuff and must die. As soon as Perl gains real threads I will work 1129is evil stuff and must die. Real threads as provided by Coro are fully
699on thread support for it. 1130supported (and enhanced support is available via L<Coro::EV>).
700 1131
701=head1 FORK 1132=head1 FORK
702 1133
703Most of the "improved" event delivering mechanisms of modern operating 1134Most of the "improved" event delivering mechanisms of modern operating
704systems have quite a few problems with fork(2) (to put it bluntly: it is 1135systems have quite a few problems with fork(2) (to put it bluntly: it is
720our $DIED = sub { 1151our $DIED = sub {
721 warn "EV: error in callback (ignoring): $@"; 1152 warn "EV: error in callback (ignoring): $@";
722}; 1153};
723 1154
724default_loop 1155default_loop
725 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; 1156 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
726 1157
7271; 11581;
728 1159
729=head1 SEE ALSO 1160=head1 SEE ALSO
730 1161
731L<EV::DNS>. 1162L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
1163event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
1164coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1165event-loop agnostic and portable event driven programming.
732 1166
733=head1 AUTHOR 1167=head1 AUTHOR
734 1168
735 Marc Lehmann <schmorp@schmorp.de> 1169 Marc Lehmann <schmorp@schmorp.de>
736 http://home.schmorp.de/ 1170 http://home.schmorp.de/
737 1171
738=cut 1172=cut
739 1173

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