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Revision 1.79 by root, Sat Dec 22 16:37:07 2007 UTC vs.
Revision 1.160 by root, Fri Nov 22 14:51:14 2019 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::run; # loop until EV::break is called or all watchers stop
53 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled 53 EV::run EV::RUN_ONCE; # block until at least one event could be handled
54 EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block 54 EV::run EV::RUN_NOWAIT; # try to handle same events, but do not block
55
56=head1 BEFORE YOU START USING THIS MODULE
57
58If you only need timer, I/O, signal, child and idle watchers and not the
59advanced functionality of this module, consider using L<AnyEvent> instead,
60specifically the simplified API described in L<AE>.
61
62When used with EV as backend, the L<AE> API is as fast as the native L<EV>
63API, but your programs/modules will still run with many other event loops.
55 64
56=head1 DESCRIPTION 65=head1 DESCRIPTION
57 66
58This module provides an interface to libev 67This module provides an interface to libev
59(L<http://software.schmorp.de/pkg/libev.html>). While the documentation 68(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
60below is comprehensive, one might also consult the documentation of libev 69below is comprehensive, one might also consult the documentation of
61itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on 70libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
62watcher semantics or some discussion on the available backends, or how to 71F<perldoc EV::libev>) for more subtle details on watcher semantics or some
63force a specific backend with C<LIBEV_FLAGS>, or just about in any case 72discussion on the available backends, or how to force a specific backend
64because it has much more detailed information. 73with C<LIBEV_FLAGS>, or just about in any case because it has much more
74detailed information.
75
76This module is very fast and scalable. It is actually so fast that you
77can use it through the L<AnyEvent> module, stay portable to other event
78loops (if you don't rely on any watcher types not available through it)
79and still be faster than with any other event loop currently supported in
80Perl.
81
82=head2 PORTING FROM EV 3.X to 4.X
83
84EV version 4 introduces a number of incompatible changes summarised
85here. According to the depreciation strategy used by libev, there is a
86compatibility layer in place so programs should continue to run unchanged
87(the XS interface lacks this layer, so programs using that one need to be
88updated).
89
90This compatibility layer will be switched off in some future release.
91
92All changes relevant to Perl are renames of symbols, functions and
93methods:
94
95 EV::loop => EV::run
96 EV::LOOP_NONBLOCK => EV::RUN_NOWAIT
97 EV::LOOP_ONESHOT => EV::RUN_ONCE
98
99 EV::unloop => EV::break
100 EV::UNLOOP_CANCEL => EV::BREAK_CANCEL
101 EV::UNLOOP_ONE => EV::BREAK_ONE
102 EV::UNLOOP_ALL => EV::BREAK_ALL
103
104 EV::TIMEOUT => EV::TIMER
105
106 EV::loop_count => EV::iteration
107 EV::loop_depth => EV::depth
108 EV::loop_verify => EV::verify
109
110The loop object methods corresponding to the functions above have been
111similarly renamed.
112
113=head2 MODULE EXPORTS
114
115This module does not export any symbols.
65 116
66=cut 117=cut
67 118
68package EV; 119package EV;
69 120
70use strict; 121use common::sense;
71 122
72BEGIN { 123BEGIN {
73 our $VERSION = '2.0'; 124 our $VERSION = 4.29;
74 use XSLoader; 125 use XSLoader;
126 local $^W = 0; # avoid spurious warning
75 XSLoader::load "EV", $VERSION; 127 XSLoader::load "EV", $VERSION;
76} 128}
77 129
78@EV::IO::ISA = 130@EV::IO::ISA =
79@EV::Timer::ISA = 131@EV::Timer::ISA =
… …
84@EV::Idle::ISA = 136@EV::Idle::ISA =
85@EV::Prepare::ISA = 137@EV::Prepare::ISA =
86@EV::Check::ISA = 138@EV::Check::ISA =
87@EV::Embed::ISA = 139@EV::Embed::ISA =
88@EV::Fork::ISA = 140@EV::Fork::ISA =
141@EV::Async::ISA =
89 "EV::Watcher"; 142 "EV::Watcher";
90 143
91@EV::Loop::Default::ISA = "EV::Loop"; 144@EV::Loop::Default::ISA = "EV::Loop";
92 145
93=head1 EVENT LOOPS 146=head1 EVENT LOOPS
… …
104default loop as this is fastest (perl-wise), best supported by other 157default loop as this is fastest (perl-wise), best supported by other
105modules (e.g. AnyEvent or Coro) and most portable event loop. 158modules (e.g. AnyEvent or Coro) and most portable event loop.
106 159
107For specific programs you can create additional event loops dynamically. 160For specific programs you can create additional event loops dynamically.
108 161
109=over 4 162If you want to take advantage of kqueue (which often works properly for
163sockets only) even though the default loop doesn't enable it, you can
164I<embed> a kqueue loop into the default loop: running the default loop
165will then also service the kqueue loop to some extent. See the example in
166the section about embed watchers for an example on how to achieve that.
110 167
168=over 4
169
111=item $loop = new EV::loop [$flags] 170=item $loop = new EV::Loop [$flags]
112 171
113Create a new event loop as per the specified flags. Please refer to the 172Create a new event loop as per the specified flags. Please refer to
114C<ev_loop_new ()> function description in the libev documentation 173the C<ev_loop_new ()> function description in the libev documentation
115(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>) 174(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
116for more info. 175or locally-installed as F<EV::libev> manpage) for more info.
117 176
118The loop will automatically be destroyed when it is no longer referenced 177The loop will automatically be destroyed when it is no longer referenced
119by any watcher and the loop object goes out of scope. 178by any watcher and the loop object goes out of scope.
120 179
121Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop 180If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
122is protected by this module. 181is recommended, as only the default event loop is protected by this
182module. If you I<are> embedding this loop in the default loop, this is not
183necessary, as C<EV::embed> automatically does the right thing on fork.
123 184
124=item $loop->loop_fork 185=item $loop->loop_fork
125 186
126Must be called after a fork in the child, before entering or continuing 187Must be called after a fork in the child, before entering or continuing
127the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls 188the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
128this fucntion automatically, at some performance loss (refer to the libev 189this function automatically, at some performance loss (refer to the libev
129documentation). 190documentation).
130 191
192=item $loop->verify
193
194Calls C<ev_verify> to make internal consistency checks (for debugging
195libev) and abort the program if any data structures were found to be
196corrupted.
197
131=item $loop = EV::default_loop [$flags] 198=item $loop = EV::default_loop [$flags]
132 199
133Return the default loop (which is a singleton object). 200Return the default loop (which is a singleton object). Since this module
201already creates the default loop with default flags, specifying flags here
202will not have any effect unless you destroy the default loop first, which
203isn't supported. So in short: don't do it, and if you break it, you get to
204keep the pieces.
134 205
135=back 206=back
136 207
137 208
138=head1 BASIC INTERFACE 209=head1 BASIC INTERFACE
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155 226
156Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this 227Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
157instance of EV, the set of recommended backends (supposed to be good) for 228instance of EV, the set of recommended backends (supposed to be good) for
158this platform and the set of embeddable backends (see EMBED WATCHERS). 229this platform and the set of embeddable backends (see EMBED WATCHERS).
159 230
231=item EV::sleep $seconds
232
233Block the process for the given number of (fractional) seconds.
234
160=item $time = EV::time 235=item $time = EV::time
161 236
162Returns the current time in (fractional) seconds since the epoch. 237Returns the current time in (fractional) seconds since the epoch.
163 238
164=item $time = EV::now 239=item $time = EV::now
165 240
166=item $time = $loop->now 241=item $time = $loop->now
167 242
168Returns the time the last event loop iteration has been started. This 243Returns the time the last event loop iteration has been started. This
169is the time that (relative) timers are based on, and refering to it is 244is the time that (relative) timers are based on, and referring to it is
170usually faster then calling EV::time. 245usually faster then calling EV::time.
171 246
247=item EV::now_update
248
249=item $loop->now_update
250
251Establishes the current time by querying the kernel, updating the time
252returned by C<EV::now> in the progress. This is a costly operation and
253is usually done automatically within C<EV::run>.
254
255This function is rarely useful, but when some event callback runs for a
256very long time without entering the event loop, updating libev's idea of
257the current time is a good idea.
258
259=item EV::suspend
260
261=item $loop->suspend
262
263=item EV::resume
264
265=item $loop->resume
266
267These two functions suspend and resume a loop, for use when the loop is
268not used for a while and timeouts should not be processed.
269
270A typical use case would be an interactive program such as a game: When
271the user presses C<^Z> to suspend the game and resumes it an hour later it
272would be best to handle timeouts as if no time had actually passed while
273the program was suspended. This can be achieved by calling C<suspend>
274in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
275C<resume> directly afterwards to resume timer processing.
276
277Effectively, all C<timer> watchers will be delayed by the time spend
278between C<suspend> and C<resume>, and all C<periodic> watchers
279will be rescheduled (that is, they will lose any events that would have
280occured while suspended).
281
282After calling C<suspend> you B<must not> call I<any> function on the given
283loop other than C<resume>, and you B<must not> call C<resume>
284without a previous call to C<suspend>.
285
286Calling C<suspend>/C<resume> has the side effect of updating the event
287loop time (see C<now_update>).
288
172=item $backend = EV::backend 289=item $backend = EV::backend
173 290
174=item $backend = $loop->backend 291=item $backend = $loop->backend
175 292
176Returns an integer describing the backend used by libev (EV::METHOD_SELECT 293Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
177or EV::METHOD_EPOLL). 294or EV::BACKEND_EPOLL).
178 295
179=item EV::loop [$flags] 296=item $active = EV::run [$flags]
180 297
181=item $loop->loop ([$flags]) 298=item $active = $loop->run ([$flags])
182 299
183Begin checking for events and calling callbacks. It returns when a 300Begin checking for events and calling callbacks. It returns when a
184callback calls EV::unloop. 301callback calls EV::break or the flags are nonzero (in which case the
302return value is true) or when there are no active watchers which reference
303the loop (keepalive is true), in which case the return value will be
304false. The return value can generally be interpreted as "if true, there is
305more work left to do".
185 306
186The $flags argument can be one of the following: 307The $flags argument can be one of the following:
187 308
188 0 as above 309 0 as above
189 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 310 EV::RUN_ONCE block at most once (wait, but do not loop)
190 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 311 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
191 312
192=item EV::unloop [$how] 313=item EV::break [$how]
193 314
194=item $loop->unloop ([$how]) 315=item $loop->break ([$how])
195 316
196When called with no arguments or an argument of EV::UNLOOP_ONE, makes the 317When called with no arguments or an argument of EV::BREAK_ONE, makes the
197innermost call to EV::loop return. 318innermost call to EV::run return.
198 319
199When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as 320When called with an argument of EV::BREAK_ALL, all calls to EV::run will
200fast as possible. 321return as fast as possible.
201 322
202=item $count = EV::loop_count 323When called with an argument of EV::BREAK_CANCEL, any pending break will
324be cancelled.
203 325
326=item $count = EV::iteration
327
204=item $count = $loop->loop_count 328=item $count = $loop->iteration
205 329
206Return the number of times the event loop has polled for new 330Return the number of times the event loop has polled for new
207events. Sometiems useful as a generation counter. 331events. Sometimes useful as a generation counter.
208 332
209=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 333=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
210 334
211=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 335=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
212 336
… …
218| EV::WRITE>, indicating the type of I/O event you want to wait for. If 342| EV::WRITE>, indicating the type of I/O event you want to wait for. If
219you do not want to wait for some I/O event, specify C<undef> for 343you do not want to wait for some I/O event, specify C<undef> for
220C<$fh_or_undef> and C<0> for C<$events>). 344C<$fh_or_undef> and C<0> for C<$events>).
221 345
222If timeout is C<undef> or negative, then there will be no 346If timeout is C<undef> or negative, then there will be no
223timeout. Otherwise a EV::timer with this value will be started. 347timeout. Otherwise an C<EV::timer> with this value will be started.
224 348
225When an error occurs or either the timeout or I/O watcher triggers, then 349When an error occurs or either the timeout or I/O watcher triggers, then
226the callback will be called with the received event set (in general 350the callback will be called with the received event set (in general
227you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>, 351you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
228C<EV::WRITE> and C<EV::TIMEOUT>). 352C<EV::WRITE> and C<EV::TIMER>).
229 353
230EV::once doesn't return anything: the watchers stay active till either 354EV::once doesn't return anything: the watchers stay active till either
231of them triggers, then they will be stopped and freed, and the callback 355of them triggers, then they will be stopped and freed, and the callback
232invoked. 356invoked.
233 357
234=item EV::feed_fd_event ($fd, $revents) 358=item EV::feed_fd_event $fd, $revents
235 359
236=item $loop->feed_fd_event ($fd, $revents) 360=item $loop->feed_fd_event ($fd, $revents)
237 361
238Feed an event on a file descriptor into EV. EV will react to this call as 362Feed an event on a file descriptor into EV. EV will react to this call as
239if the readyness notifications specified by C<$revents> (a combination of 363if the readyness notifications specified by C<$revents> (a combination of
240C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. 364C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
241 365
242=item EV::feed_signal_event ($signal) 366=item EV::feed_signal_event $signal
243 367
244Feed a signal event into EV. EV will react to this call as if the signal 368Feed a signal event into the default loop. EV will react to this call as
245specified by C<$signal> had occured. 369if the signal specified by C<$signal> had occured.
370
371=item EV::feed_signal $signal
372
373Feed a signal event into EV - unlike C<EV::feed_signal_event>, this works
374regardless of which loop has registered the signal, and is mainly useful
375for custom signal implementations.
246 376
247=item EV::set_io_collect_interval $time 377=item EV::set_io_collect_interval $time
248 378
249=item $loop->set_io_collect_interval ($time) 379=item $loop->set_io_collect_interval ($time)
250 380
… …
252 382
253=item $loop->set_timeout_collect_interval ($time) 383=item $loop->set_timeout_collect_interval ($time)
254 384
255These advanced functions set the minimum block interval when polling for I/O events and the minimum 385These advanced functions set the minimum block interval when polling for I/O events and the minimum
256wait interval for timer events. See the libev documentation at 386wait interval for timer events. See the libev documentation at
257L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> for 387L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
258a more detailed discussion. 388(locally installed as F<EV::libev>) for a more detailed discussion.
389
390=item $count = EV::pending_count
391
392=item $count = $loop->pending_count
393
394Returns the number of currently pending watchers.
395
396=item EV::invoke_pending
397
398=item $loop->invoke_pending
399
400Invoke all currently pending watchers.
259 401
260=back 402=back
261 403
262 404
263=head1 WATCHER OBJECTS 405=head1 WATCHER OBJECTS
264 406
265A watcher is an object that gets created to record your interest in some 407A watcher is an object that gets created to record your interest in some
266event. For instance, if you want to wait for STDIN to become readable, you 408event. For instance, if you want to wait for STDIN to become readable, you
267would create an EV::io watcher for that: 409would create an EV::io watcher for that:
268 410
269 my $watcher = EV::io *STDIN, EV::READ, sub { 411 my $watcher = EV::io *STDIN, EV::READ, sub {
270 my ($watcher, $revents) = @_; 412 my ($watcher, $revents) = @_;
271 warn "yeah, STDIN should now be readable without blocking!\n" 413 warn "yeah, STDIN should now be readable without blocking!\n"
272 }; 414 };
273 415
274All watchers can be active (waiting for events) or inactive (paused). Only 416All watchers can be active (waiting for events) or inactive (paused). Only
275active watchers will have their callbacks invoked. All callbacks will be 417active watchers will have their callbacks invoked. All callbacks will be
276called with at least two arguments: the watcher and a bitmask of received 418called with at least two arguments: the watcher and a bitmask of received
277events. 419events.
278 420
279Each watcher type has its associated bit in revents, so you can use the 421Each watcher type has its associated bit in revents, so you can use the
280same callback for multiple watchers. The event mask is named after the 422same callback for multiple watchers. The event mask is named after the
281type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 423type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
282EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events 424EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
283(which can set both EV::READ and EV::WRITE bits), and EV::timer (which 425(which can set both EV::READ and EV::WRITE bits).
284uses EV::TIMEOUT).
285 426
286In the rare case where one wants to create a watcher but not start it at 427In the rare case where one wants to create a watcher but not start it at
287the same time, each constructor has a variant with a trailing C<_ns> in 428the same time, each constructor has a variant with a trailing C<_ns> in
288its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. 429its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
289 430
… …
366returns its C<$revents> bitset (as if its callback was invoked). If the 507returns its C<$revents> bitset (as if its callback was invoked). If the
367watcher isn't pending it does nothing and returns C<0>. 508watcher isn't pending it does nothing and returns C<0>.
368 509
369=item $previous_state = $w->keepalive ($bool) 510=item $previous_state = $w->keepalive ($bool)
370 511
371Normally, C<EV::loop> will return when there are no active watchers 512Normally, C<EV::run> will return when there are no active watchers
372(which is a "deadlock" because no progress can be made anymore). This is 513(which is a "deadlock" because no progress can be made anymore). This is
373convinient because it allows you to start your watchers (and your jobs), 514convenient because it allows you to start your watchers (and your jobs),
374call C<EV::loop> once and when it returns you know that all your jobs are 515call C<EV::run> once and when it returns you know that all your jobs are
375finished (or they forgot to register some watchers for their task :). 516finished (or they forgot to register some watchers for their task :).
376 517
377Sometimes, however, this gets in your way, for example when the module 518Sometimes, however, this gets in your way, for example when the module
378that calls C<EV::loop> (usually the main program) is not the same module 519that calls C<EV::run> (usually the main program) is not the same module
379as a long-living watcher (for example a DNS client module written by 520as a long-living watcher (for example a DNS client module written by
380somebody else even). Then you might want any outstanding requests to be 521somebody else even). Then you might want any outstanding requests to be
381handled, but you would not want to keep C<EV::loop> from returning just 522handled, but you would not want to keep C<EV::run> from returning just
382because you happen to have this long-running UDP port watcher. 523because you happen to have this long-running UDP port watcher.
383 524
384In this case you can clear the keepalive status, which means that even 525In this case you can clear the keepalive status, which means that even
385though your watcher is active, it won't keep C<EV::loop> from returning. 526though your watcher is active, it won't keep C<EV::run> from returning.
386 527
387The initial value for keepalive is true (enabled), and you cna change it 528The initial value for keepalive is true (enabled), and you can change it
388any time. 529any time.
389 530
390Example: Register an I/O watcher for some UDP socket but do not keep the 531Example: Register an I/O watcher for some UDP socket but do not keep the
391event loop from running just because of that watcher. 532event loop from running just because of that watcher.
392 533
393 my $udp_socket = ... 534 my $udp_socket = ...
394 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 535 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
395 $1000udp_watcher->keepalive (0); 536 $udp_watcher->keepalive (0);
396 537
397=item $loop = $w->loop 538=item $loop = $w->loop
398 539
399Return the loop that this watcher is attached to. 540Return the loop that this watcher is attached to.
400 541
… …
457 598
458=item $w = $loop->timer ($after, $repeat, $callback) 599=item $w = $loop->timer ($after, $repeat, $callback)
459 600
460=item $w = $loop->timer_ns ($after, $repeat, $callback) 601=item $w = $loop->timer_ns ($after, $repeat, $callback)
461 602
462Calls the callback after C<$after> seconds (which may be fractional). If 603Calls the callback after C<$after> seconds (which may be fractional or
463C<$repeat> is non-zero, the timer will be restarted (with the $repeat 604negative). If C<$repeat> is non-zero, the timer will be restarted (with
464value as $after) after the callback returns. 605the $repeat value as $after) after the callback returns.
465 606
466This means that the callback would be called roughly after C<$after> 607This means that the callback would be called roughly after C<$after>
467seconds, and then every C<$repeat> seconds. The timer does his best not 608seconds, and then every C<$repeat> seconds. The timer does his best not
468to drift, but it will not invoke the timer more often then once per event 609to drift, but it will not invoke the timer more often then once per event
469loop iteration, and might drift in other cases. If that isn't acceptable, 610loop iteration, and might drift in other cases. If that isn't acceptable,
… …
473in front of the machine while the timer is running and changes the system 614in front of the machine while the timer is running and changes the system
474clock, the timer will nevertheless run (roughly) the same time. 615clock, the timer will nevertheless run (roughly) the same time.
475 616
476The C<timer_ns> variant doesn't start (activate) the newly created watcher. 617The C<timer_ns> variant doesn't start (activate) the newly created watcher.
477 618
478=item $w->set ($after, $repeat) 619=item $w->set ($after, $repeat = 0)
479 620
480Reconfigures the watcher, see the constructor above for details. Can be called at 621Reconfigures the watcher, see the constructor above for details. Can be called at
481any time. 622any time.
482 623
483=item $w->again 624=item $w->again
625
626=item $w->again ($repeat)
484 627
485Similar to the C<start> method, but has special semantics for repeating timers: 628Similar to the C<start> method, but has special semantics for repeating timers:
486 629
487If the timer is active and non-repeating, it will be stopped. 630If the timer is active and non-repeating, it will be stopped.
488 631
… …
495 638
496This behaviour is useful when you have a timeout for some IO 639This behaviour is useful when you have a timeout for some IO
497operation. You create a timer object with the same value for C<$after> and 640operation. You create a timer object with the same value for C<$after> and
498C<$repeat>, and then, in the read/write watcher, run the C<again> method 641C<$repeat>, and then, in the read/write watcher, run the C<again> method
499on the timeout. 642on the timeout.
643
644If called with a C<$repeat> argument, then it uses this a timer repeat
645value.
646
647=item $after = $w->remaining
648
649Calculates and returns the remaining time till the timer will fire.
500 650
501=back 651=back
502 652
503 653
504=head3 PERIODIC WATCHERS - to cron or not to cron? 654=head3 PERIODIC WATCHERS - to cron or not to cron?
… …
529This time simply fires at the wallclock time C<$at> and doesn't repeat. It 679This time simply fires at the wallclock time C<$at> and doesn't repeat. It
530will not adjust when a time jump occurs, that is, if it is to be run 680will not adjust when a time jump occurs, that is, if it is to be run
531at January 1st 2011 then it will run when the system time reaches or 681at January 1st 2011 then it will run when the system time reaches or
532surpasses this time. 682surpasses this time.
533 683
534=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 684=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
535 685
536In this mode the watcher will always be scheduled to time out at the 686In this mode the watcher will always be scheduled to time out at the
537next C<$at + N * $interval> time (for some integer N) and then repeat, 687next C<$at + N * $interval> time (for the lowest integer N) and then repeat,
538regardless of any time jumps. 688regardless of any time jumps. Note that, since C<N> can be negative, the
689first trigger can happen before C<$at>.
539 690
540This can be used to create timers that do not drift with respect to system 691This can be used to create timers that do not drift with respect to system
541time: 692time:
542 693
543 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; 694 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
544 695
545That doesn't mean there will always be 3600 seconds in between triggers, 696That doesn't mean there will always be 3600 seconds in between triggers,
546but only that the the clalback will be called when the system time shows a 697but only that the the callback will be called when the system time shows a
547full hour (UTC). 698full hour (UTC).
548 699
549Another way to think about it (for the mathematically inclined) is that 700Another way to think about it (for the mathematically inclined) is that
550EV::periodic will try to run the callback in this mode at the next 701EV::periodic will try to run the callback in this mode at the next
551possible time where C<$time = $at (mod $interval)>, regardless of any time 702possible time where C<$time = $at (mod $interval)>, regardless of any time
… …
557time the periodic watcher gets scheduled, the reschedule callback 708time the periodic watcher gets scheduled, the reschedule callback
558($reschedule_cb) will be called with the watcher as first, and the current 709($reschedule_cb) will be called with the watcher as first, and the current
559time as second argument. 710time as second argument.
560 711
561I<This callback MUST NOT stop or destroy this or any other periodic 712I<This callback MUST NOT stop or destroy this or any other periodic
562watcher, ever>. If you need to stop it, return 1e30 and stop it 713watcher, ever, and MUST NOT call any event loop functions or methods>. If
563afterwards. 714you need to stop it, return 1e30 and stop it afterwards. You may create
715and start an C<EV::prepare> watcher for this task.
564 716
565It must return the next time to trigger, based on the passed time value 717It must return the next time to trigger, based on the passed time value
566(that is, the lowest time value larger than to the second argument). It 718(that is, the lowest time value larger than or equal to to the second
567will usually be called just before the callback will be triggered, but 719argument). It will usually be called just before the callback will be
568might be called at other times, too. 720triggered, but might be called at other times, too.
569 721
570This can be used to create very complex timers, such as a timer that 722This can be used to create very complex timers, such as a timer that
571triggers on each midnight, local time (actually 24 hours after the last 723triggers on each midnight, local time (actually one day after the last
572midnight, to keep the example simple. If you know a way to do it correctly 724midnight, to keep the example simple):
573in about the same space (without requiring elaborate modules), drop me a
574note :):
575 725
576 my $daily = EV::periodic 0, 0, sub { 726 my $daily = EV::periodic 0, 0, sub {
577 my ($w, $now) = @_; 727 my ($w, $now) = @_;
578 728
579 use Time::Local (); 729 use Time::Local ();
580 my (undef, undef, undef, $d, $m, $y) = localtime $now; 730 my (undef, undef, undef, $d, $m, $y) = localtime $now;
581 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y 731 Time::Local::timelocal_nocheck 0, 0, 0, $d + 1, $m, $y
582 }, sub { 732 }, sub {
583 print "it's midnight or likely shortly after, now\n"; 733 print "it's midnight or likely shortly after, now\n";
584 }; 734 };
585 735
586=back 736=back
… …
609 759
610=item $w = EV::signal $signal, $callback 760=item $w = EV::signal $signal, $callback
611 761
612=item $w = EV::signal_ns $signal, $callback 762=item $w = EV::signal_ns $signal, $callback
613 763
764=item $w = $loop->signal ($signal, $callback)
765
766=item $w = $loop->signal_ns ($signal, $callback)
767
614Call the callback when $signal is received (the signal can be specified by 768Call the callback when $signal is received (the signal can be specified by
615number or by name, just as with C<kill> or C<%SIG>). 769number or by name, just as with C<kill> or C<%SIG>).
770
771Only one event loop can grab a given signal - attempting to grab the same
772signal from two EV loops will crash the program immediately or cause data
773corruption.
616 774
617EV will grab the signal for the process (the kernel only allows one 775EV will grab the signal for the process (the kernel only allows one
618component to receive a signal at a time) when you start a signal watcher, 776component to receive a signal at a time) when you start a signal watcher,
619and removes it again when you stop it. Perl does the same when you 777and removes it again when you stop it. Perl does the same when you
620add/remove callbacks to C<%SIG>, so watch out. 778add/remove callbacks to C<%SIG>, so watch out.
… …
640 798
641=head3 CHILD WATCHERS - watch out for process status changes 799=head3 CHILD WATCHERS - watch out for process status changes
642 800
643=over 4 801=over 4
644 802
645=item $w = EV::child $pid, $callback 803=item $w = EV::child $pid, $trace, $callback
646 804
647=item $w = EV::child_ns $pid, $callback 805=item $w = EV::child_ns $pid, $trace, $callback
648 806
649=item $w = $loop->child ($pid, $callback) 807=item $w = $loop->child ($pid, $trace, $callback)
650 808
651=item $w = $loop->child_ns ($pid, $callback) 809=item $w = $loop->child_ns ($pid, $trace, $callback)
652 810
653Call the callback when a status change for pid C<$pid> (or any pid if 811Call the callback when a status change for pid C<$pid> (or any pid
654C<$pid> is 0) has been received. More precisely: when the process receives 812if C<$pid> is 0) has been received (a status change happens when the
813process terminates or is killed, or, when trace is true, additionally when
814it is stopped or continued). More precisely: when the process receives
655a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all 815a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
656changed/zombie children and call the callback. 816changed/zombie children and call the callback.
657 817
658It is valid (and fully supported) to install a child watcher after a child 818It is valid (and fully supported) to install a child watcher after a child
659has exited but before the event loop has started its next iteration (for 819has exited but before the event loop has started its next iteration (for
… …
666You can have as many pid watchers per pid as you want, they will all be 826You can have as many pid watchers per pid as you want, they will all be
667called. 827called.
668 828
669The C<child_ns> variant doesn't start (activate) the newly created watcher. 829The C<child_ns> variant doesn't start (activate) the newly created watcher.
670 830
671=item $w->set ($pid) 831=item $w->set ($pid, $trace)
672 832
673Reconfigures the watcher, see the constructor above for details. Can be called at 833Reconfigures the watcher, see the constructor above for details. Can be called at
674any time. 834any time.
675 835
676=item $current_pid = $w->pid 836=item $current_pid = $w->pid
677
678=item $old_pid = $w->pid ($new_pid)
679 837
680Returns the previously set process id and optionally set a new one. 838Returns the previously set process id and optionally set a new one.
681 839
682=item $exit_status = $w->rstatus 840=item $exit_status = $w->rstatus
683 841
… …
845=item $w = $loop->check_ns ($callback) 1003=item $w = $loop->check_ns ($callback)
846 1004
847Call the callback just after the process wakes up again (after it has 1005Call the callback just after the process wakes up again (after it has
848gathered events), but before any other callbacks have been invoked. 1006gathered events), but before any other callbacks have been invoked.
849 1007
850This is used to integrate other event-based software into the EV 1008This can be used to integrate other event-based software into the EV
851mainloop: You register a prepare callback and in there, you create io and 1009mainloop: You register a prepare callback and in there, you create io and
852timer watchers as required by the other software. Here is a real-world 1010timer watchers as required by the other software. Here is a real-world
853example of integrating Net::SNMP (with some details left out): 1011example of integrating Net::SNMP (with some details left out):
854 1012
855 our @snmp_watcher; 1013 our @snmp_watcher;
… …
885 # make the dispatcher handle any new stuff 1043 # make the dispatcher handle any new stuff
886 ... not shown 1044 ... not shown
887 }; 1045 };
888 1046
889The callbacks of the created watchers will not be called as the watchers 1047The callbacks of the created watchers will not be called as the watchers
890are destroyed before this cna happen (remember EV::check gets called 1048are destroyed before this can happen (remember EV::check gets called
891first). 1049first).
892 1050
893The C<check_ns> variant doesn't start (activate) the newly created watcher. 1051The C<check_ns> variant doesn't start (activate) the newly created watcher.
1052
1053=item EV::CHECK constant issues
1054
1055Like all other watcher types, there is a bitmask constant for use in
1056C<$revents> and other places. The C<EV::CHECK> is special as it has
1057the same name as the C<CHECK> sub called by Perl. This doesn't cause
1058big issues on newer perls (beginning with 5.8.9), but it means thatthe
1059constant must be I<inlined>, i.e. runtime calls will not work. That means
1060that as long as you always C<use EV> and then C<EV::CHECK> you are on the
1061safe side.
894 1062
895=back 1063=back
896 1064
897 1065
898=head3 FORK WATCHERS - the audacity to resume the event loop after a fork 1066=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
… …
926loop, other types of watchers might be handled in a delayed or incorrect 1094loop, other types of watchers might be handled in a delayed or incorrect
927fashion and must not be used). 1095fashion and must not be used).
928 1096
929See the libev documentation at 1097See the libev documentation at
930L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> 1098L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
931for more details. 1099(locally installed as F<EV::libev>) for more details.
932 1100
933In short, this watcher is most useful on BSD systems without working 1101In short, this watcher is most useful on BSD systems without working
934kqueue to still be able to handle a large number of sockets: 1102kqueue to still be able to handle a large number of sockets:
935 1103
936 my $socket_loop; 1104 my $socket_loop;
937 1105
938 # check wether we use SELECT or POLL _and_ KQUEUE is supported 1106 # check wether we use SELECT or POLL _and_ KQUEUE is supported
939 if ( 1107 if (
940 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 1108 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
941 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 1109 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
942 ) { 1110 ) {
943 # use kqueue for sockets 1111 # use kqueue for sockets
944 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 1112 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
945 } 1113 }
946 1114
947 # use the default loop otherwise 1115 # use the default loop otherwise
948 $socket_loop ||= EV::default_loop; 1116 $socket_loop ||= EV::default_loop;
949 1117
950=over 4 1118=over 4
951 1119
952=item $w = EV::embed $otherloop, $callback 1120=item $w = EV::embed $otherloop[, $callback]
953 1121
954=item $w = EV::embed_ns $otherloop, $callback 1122=item $w = EV::embed_ns $otherloop[, $callback]
955 1123
956=item $w = $loop->embed ($otherloop, $callback) 1124=item $w = $loop->embed ($otherloop[, $callback])
957 1125
958=item $w = $loop->embed_ns ($otherloop, $callback) 1126=item $w = $loop->embed_ns ($otherloop[, $callback])
959 1127
960Call the callback when the embedded event loop (C<$otherloop>) has any 1128Call the callback when the embedded event loop (C<$otherloop>) has any
961I/O activity. The C<$callback> should alwas be specified as C<undef> in 1129I/O activity. The C<$callback> is optional: if it is missing, then the
962this version of EV, which means the embedded event loop will be managed 1130embedded event loop will be managed automatically (which is recommended),
963automatically. 1131otherwise you have to invoke C<sweep> yourself.
964 1132
965The C<embed_ns> variant doesn't start (activate) the newly created watcher. 1133The C<embed_ns> variant doesn't start (activate) the newly created watcher.
966 1134
967=back 1135=back
1136
1137=head3 ASYNC WATCHERS - how to wake up another event loop
1138
1139Async watchers are provided by EV, but have little use in perl directly,
1140as perl neither supports threads running in parallel nor direct access to
1141signal handlers or other contexts where they could be of value.
1142
1143It is, however, possible to use them from the XS level.
1144
1145Please see the libev documentation for further details.
1146
1147=over 4
1148
1149=item $w = EV::async $callback
1150
1151=item $w = EV::async_ns $callback
1152
1153=item $w = $loop->async ($callback)
1154
1155=item $w = $loop->async_ns ($callback)
1156
1157=item $w->send
1158
1159=item $bool = $w->async_pending
1160
1161=back
1162
1163=head3 CLEANUP WATCHERS - how to clean up when the event loop goes away
1164
1165Cleanup watchers are not supported on the Perl level, they can only be
1166used via XS currently.
968 1167
969 1168
970=head1 PERL SIGNALS 1169=head1 PERL SIGNALS
971 1170
972While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour 1171While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
… …
984 my $async_check = EV::check sub { }; 1183 my $async_check = EV::check sub { };
985 1184
986This ensures that perl gets into control for a short time to handle any 1185This ensures that perl gets into control for a short time to handle any
987pending signals, and also ensures (slightly) slower overall operation. 1186pending signals, and also ensures (slightly) slower overall operation.
988 1187
989=head1 THREADS 1188=head1 ITHREADS
990 1189
991Threads are not supported by this module in any way. Perl pseudo-threads 1190Ithreads are not supported by this module in any way. Perl pseudo-threads
992is evil stuff and must die. As soon as Perl gains real threads I will work 1191is evil stuff and must die. Real threads as provided by Coro are fully
993on thread support for it. 1192supported (and enhanced support is available via L<Coro::EV>).
994 1193
995=head1 FORK 1194=head1 FORK
996 1195
997Most of the "improved" event delivering mechanisms of modern operating 1196Most of the "improved" event delivering mechanisms of modern operating
998systems have quite a few problems with fork(2) (to put it bluntly: it is 1197systems have quite a few problems with fork(2) (to put it bluntly: it is
… …
1020 1219
10211; 12201;
1022 1221
1023=head1 SEE ALSO 1222=head1 SEE ALSO
1024 1223
1224L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS>
1025L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as 1225(asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as event
1026event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient 1226loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient thread
1027coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP). 1227integration), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1228event-loop agnostic and portable event driven programming.
1028 1229
1029=head1 AUTHOR 1230=head1 AUTHOR
1030 1231
1031 Marc Lehmann <schmorp@schmorp.de> 1232 Marc Lehmann <schmorp@schmorp.de>
1032 http://home.schmorp.de/ 1233 http://home.schmorp.de/
1033 1234
1034=cut 1235=cut
1035 1236

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