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Revision 1.96 by root, Thu May 22 02:44:57 2008 UTC vs.
Revision 1.166 by root, Wed Aug 16 16:03:37 2023 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 $w = EV::child 666, 0, sub {
41 my ($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://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>) for more 70libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
62subtle details on watcher semantics or some discussion on the available 71F<perldoc EV::libev>) for more subtle details on watcher semantics or some
63backends, or how to force a specific backend with C<LIBEV_FLAGS>, or just 72discussion on the available backends, or how to force a specific backend
64about in any case because it has much more detailed information. 73with C<LIBEV_FLAGS>, or just about in any case because it has much more
74detailed information.
65 75
66This module is very fast and scalable. It is actually so fast that you 76This module is very fast and scalable. It is actually so fast that you
67can use it through the L<AnyEvent> module, stay portable to other event 77can use it through the L<AnyEvent> module, stay portable to other event
68loops (if you don't rely on any watcher types not available through it) 78loops (if you don't rely on any watcher types not available through it)
69and still be faster than with any other event loop currently supported in 79and still be faster than with any other event loop currently supported in
70Perl. 80Perl.
71 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.
116
72=cut 117=cut
73 118
74package EV; 119package EV;
75 120
76use strict; 121use common::sense;
77 122
78BEGIN { 123BEGIN {
79 our $VERSION = '3.41'; 124 our $VERSION = '4.34';
80 use XSLoader; 125 use XSLoader;
126 local $^W = 0; # avoid spurious warning
81 XSLoader::load "EV", $VERSION; 127 XSLoader::load "EV", $VERSION;
82} 128}
83 129
84@EV::IO::ISA = 130@EV::IO::ISA =
85@EV::Timer::ISA = 131@EV::Timer::ISA =
… …
111default loop as this is fastest (perl-wise), best supported by other 157default loop as this is fastest (perl-wise), best supported by other
112modules (e.g. AnyEvent or Coro) and most portable event loop. 158modules (e.g. AnyEvent or Coro) and most portable event loop.
113 159
114For specific programs you can create additional event loops dynamically. 160For specific programs you can create additional event loops dynamically.
115 161
116=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.
117 167
168=over 4
169
118=item $loop = new EV::loop [$flags] 170=item $loop = new EV::Loop [$flags]
119 171
120Create 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
121C<ev_loop_new ()> function description in the libev documentation 173the C<ev_loop_new ()> function description in the libev documentation
122(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>,
123for more info. 175or locally-installed as F<EV::libev> manpage) for more info.
124 176
125The loop will automatically be destroyed when it is no longer referenced 177The loop will automatically be destroyed when it is no longer referenced
126by any watcher and the loop object goes out of scope. 178by any watcher and the loop object goes out of scope.
127 179
128Using 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>
129is 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.
130 184
131=item $loop->loop_fork 185=item $loop->loop_fork
132 186
133Must 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
134the 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
135this function automatically, at some performance loss (refer to the libev 189this function automatically, at some performance loss (refer to the libev
136documentation). 190documentation).
137 191
138=item $loop->loop_verify 192=item $loop->verify
139 193
140Calls C<ev_verify> to make internal consistency checks (for debugging 194Calls C<ev_verify> to make internal consistency checks (for debugging
141libev) and abort the program if any data structures wree found to be 195libev) and abort the program if any data structures were found to be
142corrupted. 196corrupted.
143 197
144=item $loop = EV::default_loop [$flags] 198=item $loop = EV::default_loop [$flags]
145 199
146Return the default loop (which is a singleton object). Since this module 200Return the default loop (which is a singleton object). Since this module
147already creates the default loop with default flags, specifying flags here 201already creates the default loop with default flags, specifying flags here
148will not have any effect unless you destroy the default loop. 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.
149 205
150=back 206=back
151 207
152 208
153=head1 BASIC INTERFACE 209=head1 BASIC INTERFACE
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183=item $time = EV::now 239=item $time = EV::now
184 240
185=item $time = $loop->now 241=item $time = $loop->now
186 242
187Returns the time the last event loop iteration has been started. This 243Returns the time the last event loop iteration has been started. This
188is 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
189usually faster then calling EV::time. 245usually faster then calling EV::time.
190 246
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
191=item $backend = EV::backend 289=item $backend = EV::backend
192 290
193=item $backend = $loop->backend 291=item $backend = $loop->backend
194 292
195Returns an integer describing the backend used by libev (EV::METHOD_SELECT 293Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
196or EV::METHOD_EPOLL). 294or EV::BACKEND_EPOLL).
197 295
198=item EV::loop [$flags] 296=item $active = EV::run [$flags]
199 297
200=item $loop->loop ([$flags]) 298=item $active = $loop->run ([$flags])
201 299
202Begin checking for events and calling callbacks. It returns when a 300Begin checking for events and calling callbacks. It returns when a
203callback 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".
204 306
205The $flags argument can be one of the following: 307The $flags argument can be one of the following:
206 308
207 0 as above 309 0 as above
208 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 310 EV::RUN_ONCE block at most once (wait, but do not loop)
209 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 311 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
210 312
211=item EV::unloop [$how] 313=item EV::break [$how]
212 314
213=item $loop->unloop ([$how]) 315=item $loop->break ([$how])
214 316
215When 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
216innermost call to EV::loop return. 318innermost call to EV::run return.
217 319
218When 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
219fast as possible. 321return as fast as possible.
220 322
221=item $count = EV::loop_count 323When called with an argument of EV::BREAK_CANCEL, any pending break will
324be cancelled.
222 325
326=item $count = EV::iteration
327
223=item $count = $loop->loop_count 328=item $count = $loop->iteration
224 329
225Return the number of times the event loop has polled for new 330Return the number of times the event loop has polled for new
226events. Sometiems useful as a generation counter. 331events. Sometimes useful as a generation counter.
227 332
228=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 333=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
229 334
230=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 335=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
231 336
… …
237| 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
238you 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
239C<$fh_or_undef> and C<0> for C<$events>). 344C<$fh_or_undef> and C<0> for C<$events>).
240 345
241If timeout is C<undef> or negative, then there will be no 346If timeout is C<undef> or negative, then there will be no
242timeout. Otherwise a EV::timer with this value will be started. 347timeout. Otherwise an C<EV::timer> with this value will be started.
243 348
244When 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
245the callback will be called with the received event set (in general 350the callback will be called with the received event set (in general
246you 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>,
247C<EV::WRITE> and C<EV::TIMEOUT>). 352C<EV::WRITE> and C<EV::TIMER>).
248 353
249EV::once doesn't return anything: the watchers stay active till either 354EV::once doesn't return anything: the watchers stay active till either
250of 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
251invoked. 356invoked.
252 357
253=item EV::feed_fd_event ($fd, $revents) 358=item EV::feed_fd_event $fd, $revents
254 359
255=item $loop->feed_fd_event ($fd, $revents) 360=item $loop->feed_fd_event ($fd, $revents)
256 361
257Feed an event on a file descriptor into EV. EV will react to this call as 362Feed an event on a file descriptor into EV. EV will react to this call as
258if the readyness notifications specified by C<$revents> (a combination of 363if the readyness notifications specified by C<$revents> (a combination of
259C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. 364C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
260 365
261=item EV::feed_signal_event ($signal) 366=item EV::feed_signal_event $signal
262 367
263Feed a signal event into EV. EV will react to this call as if the signal 368Feed a signal event into the default loop. EV will react to this call as
264specified by C<$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.
265 376
266=item EV::set_io_collect_interval $time 377=item EV::set_io_collect_interval $time
267 378
268=item $loop->set_io_collect_interval ($time) 379=item $loop->set_io_collect_interval ($time)
269 380
… …
271 382
272=item $loop->set_timeout_collect_interval ($time) 383=item $loop->set_timeout_collect_interval ($time)
273 384
274These 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
275wait interval for timer events. See the libev documentation at 386wait interval for timer events. See the libev documentation at
276L<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>
277a 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.
278 401
279=back 402=back
280 403
281 404
282=head1 WATCHER OBJECTS 405=head1 WATCHER OBJECTS
283 406
284A 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
285event. 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
286would create an EV::io watcher for that: 409would create an EV::io watcher for that:
287 410
288 my $watcher = EV::io *STDIN, EV::READ, sub { 411 my $watcher = EV::io *STDIN, EV::READ, sub {
289 my ($watcher, $revents) = @_; 412 my ($watcher, $revents) = @_;
290 warn "yeah, STDIN should now be readable without blocking!\n" 413 warn "yeah, STDIN should now be readable without blocking!\n"
291 }; 414 };
292 415
293All watchers can be active (waiting for events) or inactive (paused). Only 416All watchers can be active (waiting for events) or inactive (paused). Only
294active watchers will have their callbacks invoked. All callbacks will be 417active watchers will have their callbacks invoked. All callbacks will be
295called with at least two arguments: the watcher and a bitmask of received 418called with at least two arguments: the watcher and a bitmask of received
296events. 419events.
297 420
298Each watcher type has its associated bit in revents, so you can use the 421Each watcher type has its associated bit in revents, so you can use the
299same callback for multiple watchers. The event mask is named after the 422same callback for multiple watchers. The event mask is named after the
300type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 423type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
301EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events 424EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
302(which can set both EV::READ and EV::WRITE bits), and EV::timer (which 425(which can set both EV::READ and EV::WRITE bits).
303uses EV::TIMEOUT).
304 426
305In the rare case where one wants to create a watcher but not start it at 427In the rare case where one wants to create a watcher but not start it at
306the same time, each constructor has a variant with a trailing C<_ns> in 428the same time, each constructor has a variant with a trailing C<_ns> in
307its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. 429its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
308 430
… …
385returns its C<$revents> bitset (as if its callback was invoked). If the 507returns its C<$revents> bitset (as if its callback was invoked). If the
386watcher isn't pending it does nothing and returns C<0>. 508watcher isn't pending it does nothing and returns C<0>.
387 509
388=item $previous_state = $w->keepalive ($bool) 510=item $previous_state = $w->keepalive ($bool)
389 511
390Normally, C<EV::loop> will return when there are no active watchers 512Normally, C<EV::run> will return when there are no active watchers
391(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
392convinient because it allows you to start your watchers (and your jobs), 514convenient because it allows you to start your watchers (and your jobs),
393call 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
394finished (or they forgot to register some watchers for their task :). 516finished (or they forgot to register some watchers for their task :).
395 517
396Sometimes, however, this gets in your way, for example when the module 518Sometimes, however, this gets in your way, for example when the module
397that 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
398as 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
399somebody else even). Then you might want any outstanding requests to be 521somebody else even). Then you might want any outstanding requests to be
400handled, 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
401because you happen to have this long-running UDP port watcher. 523because you happen to have this long-running UDP port watcher.
402 524
403In 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
404though 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.
405 527
406The 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
407any time. 529any time.
408 530
409Example: 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
410event loop from running just because of that watcher. 532event loop from running just because of that watcher.
411 533
412 my $udp_socket = ... 534 my $udp_socket = ...
413 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 535 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
414 $1000udp_watcher->keepalive (0); 536 $udp_watcher->keepalive (0);
415 537
416=item $loop = $w->loop 538=item $loop = $w->loop
417 539
418Return the loop that this watcher is attached to. 540Return the loop that this watcher is attached to.
419 541
… …
476 598
477=item $w = $loop->timer ($after, $repeat, $callback) 599=item $w = $loop->timer ($after, $repeat, $callback)
478 600
479=item $w = $loop->timer_ns ($after, $repeat, $callback) 601=item $w = $loop->timer_ns ($after, $repeat, $callback)
480 602
481Calls the callback after C<$after> seconds (which may be fractional). If 603Calls the callback after C<$after> seconds (which may be fractional or
482C<$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
483value as $after) after the callback returns. 605the $repeat value as $after) after the callback returns.
484 606
485This means that the callback would be called roughly after C<$after> 607This means that the callback would be called roughly after C<$after>
486seconds, and then every C<$repeat> seconds. The timer does his best not 608seconds, and then every C<$repeat> seconds. The timer does his best not
487to 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
488loop 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,
… …
492in 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
493clock, the timer will nevertheless run (roughly) the same time. 615clock, the timer will nevertheless run (roughly) the same time.
494 616
495The 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.
496 618
497=item $w->set ($after, $repeat) 619=item $w->set ($after, $repeat = 0)
498 620
499Reconfigures 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
500any time. 622any time.
501 623
502=item $w->again 624=item $w->again
625
626=item $w->again ($repeat)
503 627
504Similar 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:
505 629
506If the timer is active and non-repeating, it will be stopped. 630If the timer is active and non-repeating, it will be stopped.
507 631
… …
514 638
515This behaviour is useful when you have a timeout for some IO 639This behaviour is useful when you have a timeout for some IO
516operation. 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
517C<$repeat>, and then, in the read/write watcher, run the C<again> method 641C<$repeat>, and then, in the read/write watcher, run the C<again> method
518on 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.
650
651=item $repeat = $w->repeat
652
653=item $old_repeat = $w->repeat ($new_repeat)
654
655Returns the current value of the repeat attribute and optionally sets a
656new one. Setting the new one will not restart the watcher - if the watcher
657is active, the new repeat value is used whenever it expires next.
519 658
520=back 659=back
521 660
522 661
523=head3 PERIODIC WATCHERS - to cron or not to cron? 662=head3 PERIODIC WATCHERS - to cron or not to cron?
… …
551surpasses this time. 690surpasses this time.
552 691
553=item * repeating interval timer ($interval > 0, $reschedule_cb = 0) 692=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
554 693
555In this mode the watcher will always be scheduled to time out at the 694In this mode the watcher will always be scheduled to time out at the
556next C<$at + N * $interval> time (for some integer N) and then repeat, 695next C<$at + N * $interval> time (for the lowest integer N) and then repeat,
557regardless of any time jumps. 696regardless of any time jumps. Note that, since C<N> can be negative, the
697first trigger can happen before C<$at>.
558 698
559This can be used to create timers that do not drift with respect to system 699This can be used to create timers that do not drift with respect to system
560time: 700time:
561 701
562 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; 702 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
563 703
564That doesn't mean there will always be 3600 seconds in between triggers, 704That doesn't mean there will always be 3600 seconds in between triggers,
565but only that the the clalback will be called when the system time shows a 705but only that the the callback will be called when the system time shows a
566full hour (UTC). 706full hour (UTC).
567 707
568Another way to think about it (for the mathematically inclined) is that 708Another way to think about it (for the mathematically inclined) is that
569EV::periodic will try to run the callback in this mode at the next 709EV::periodic will try to run the callback in this mode at the next
570possible time where C<$time = $at (mod $interval)>, regardless of any time 710possible time where C<$time = $at (mod $interval)>, regardless of any time
… …
578time as second argument. 718time as second argument.
579 719
580I<This callback MUST NOT stop or destroy this or any other periodic 720I<This callback MUST NOT stop or destroy this or any other periodic
581watcher, ever, and MUST NOT call any event loop functions or methods>. If 721watcher, ever, and MUST NOT call any event loop functions or methods>. If
582you need to stop it, return 1e30 and stop it afterwards. You may create 722you need to stop it, return 1e30 and stop it afterwards. You may create
583and start a C<EV::prepare> watcher for this task. 723and start an C<EV::prepare> watcher for this task.
584 724
585It must return the next time to trigger, based on the passed time value 725It must return the next time to trigger, based on the passed time value
586(that is, the lowest time value larger than or equal to to the second 726(that is, the lowest time value larger than or equal to to the second
587argument). It will usually be called just before the callback will be 727argument). It will usually be called just before the callback will be
588triggered, but might be called at other times, too. 728triggered, but might be called at other times, too.
589 729
590This can be used to create very complex timers, such as a timer that 730This can be used to create very complex timers, such as a timer that
591triggers on each midnight, local time (actually 24 hours after the last 731triggers on each midnight, local time (actually one day after the last
592midnight, to keep the example simple. If you know a way to do it correctly 732midnight, to keep the example simple):
593in about the same space (without requiring elaborate modules), drop me a
594note :):
595 733
596 my $daily = EV::periodic 0, 0, sub { 734 my $daily = EV::periodic 0, 0, sub {
597 my ($w, $now) = @_; 735 my ($w, $now) = @_;
598 736
599 use Time::Local (); 737 use Time::Local ();
600 my (undef, undef, undef, $d, $m, $y) = localtime $now; 738 my (undef, undef, undef, $d, $m, $y) = localtime $now;
601 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y 739 Time::Local::timelocal_nocheck 0, 0, 0, $d + 1, $m, $y
602 }, sub { 740 }, sub {
603 print "it's midnight or likely shortly after, now\n"; 741 print "it's midnight or likely shortly after, now\n";
604 }; 742 };
605 743
606=back 744=back
… …
618 756
619=item $time = $w->at 757=item $time = $w->at
620 758
621Return the time that the watcher is expected to trigger next. 759Return the time that the watcher is expected to trigger next.
622 760
761=item $offset = $w->offset
762
763=item $old_offset = $w->offset ($new_offset)
764
765Returns the current value of the offset attribute and optionally sets a
766new one. Setting the new one will not restart the watcher - if the watcher
767is active, the new offset value is used whenever it expires next.
768
769=item $interval = $w->interval
770
771=item $old_interval = $w->interval ($new_interval)
772
773See above, for the interval attribute.
774
775=item $reschedule_cb = $w->reschedule_cb
776
777=item $old_reschedule_cb = $w->reschedule_cb ($new_reschedule_cb)
778
779See above, for the reschedule callback.
780
623=back 781=back
624 782
625 783
626=head3 SIGNAL WATCHERS - signal me when a signal gets signalled! 784=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
627 785
628=over 4 786=over 4
629 787
630=item $w = EV::signal $signal, $callback 788=item $w = EV::signal $signal, $callback
631 789
632=item $w = EV::signal_ns $signal, $callback 790=item $w = EV::signal_ns $signal, $callback
791
792=item $w = $loop->signal ($signal, $callback)
793
794=item $w = $loop->signal_ns ($signal, $callback)
633 795
634Call the callback when $signal is received (the signal can be specified by 796Call the callback when $signal is received (the signal can be specified by
635number or by name, just as with C<kill> or C<%SIG>). 797number or by name, just as with C<kill> or C<%SIG>).
798
799Only one event loop can grab a given signal - attempting to grab the same
800signal from two EV loops will crash the program immediately or cause data
801corruption.
636 802
637EV will grab the signal for the process (the kernel only allows one 803EV will grab the signal for the process (the kernel only allows one
638component to receive a signal at a time) when you start a signal watcher, 804component to receive a signal at a time) when you start a signal watcher,
639and removes it again when you stop it. Perl does the same when you 805and removes it again when you stop it. Perl does the same when you
640add/remove callbacks to C<%SIG>, so watch out. 806add/remove callbacks to C<%SIG>, so watch out.
… …
707=item $pid = $w->rpid 873=item $pid = $w->rpid
708 874
709Return the pid of the awaited child (useful when you have installed a 875Return the pid of the awaited child (useful when you have installed a
710watcher for all pids). 876watcher for all pids).
711 877
878=item EV::Child::reinit [EXPERIMENTAL]
879
880Internally, libev installs a signal handler for C<SIGCHLD>. Unfortunately,
881a lot of Perl code does soemthing like C<< local $SIG{CHLD} >>, which,
882unfortunately, is broken and will not restore the signal handler.
883
884If this has happened, you can call this function to stop/rrestart the
885internal libev watcher, which will reset the signal handler.
886
887Note that this is an experimental function, whose interface might change.
888
712=back 889=back
713 890
714 891
715=head3 STAT WATCHERS - did the file attributes just change? 892=head3 STAT WATCHERS - did the file attributes just change?
716 893
… …
865=item $w = $loop->check_ns ($callback) 1042=item $w = $loop->check_ns ($callback)
866 1043
867Call the callback just after the process wakes up again (after it has 1044Call the callback just after the process wakes up again (after it has
868gathered events), but before any other callbacks have been invoked. 1045gathered events), but before any other callbacks have been invoked.
869 1046
870This is used to integrate other event-based software into the EV 1047This can be used to integrate other event-based software into the EV
871mainloop: You register a prepare callback and in there, you create io and 1048mainloop: You register a prepare callback and in there, you create io and
872timer watchers as required by the other software. Here is a real-world 1049timer watchers as required by the other software. Here is a real-world
873example of integrating Net::SNMP (with some details left out): 1050example of integrating Net::SNMP (with some details left out):
874 1051
875 our @snmp_watcher; 1052 our @snmp_watcher;
… …
905 # make the dispatcher handle any new stuff 1082 # make the dispatcher handle any new stuff
906 ... not shown 1083 ... not shown
907 }; 1084 };
908 1085
909The callbacks of the created watchers will not be called as the watchers 1086The callbacks of the created watchers will not be called as the watchers
910are destroyed before this cna happen (remember EV::check gets called 1087are destroyed before this can happen (remember EV::check gets called
911first). 1088first).
912 1089
913The C<check_ns> variant doesn't start (activate) the newly created watcher. 1090The C<check_ns> variant doesn't start (activate) the newly created watcher.
1091
1092=item EV::CHECK constant issues
1093
1094Like all other watcher types, there is a bitmask constant for use in
1095C<$revents> and other places. The C<EV::CHECK> is special as it has
1096the same name as the C<CHECK> sub called by Perl. This doesn't cause
1097big issues on newer perls (beginning with 5.8.9), but it means thatthe
1098constant must be I<inlined>, i.e. runtime calls will not work. That means
1099that as long as you always C<use EV> and then C<EV::CHECK> you are on the
1100safe side.
914 1101
915=back 1102=back
916 1103
917 1104
918=head3 FORK WATCHERS - the audacity to resume the event loop after a fork 1105=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
… …
946loop, other types of watchers might be handled in a delayed or incorrect 1133loop, other types of watchers might be handled in a delayed or incorrect
947fashion and must not be used). 1134fashion and must not be used).
948 1135
949See the libev documentation at 1136See the libev documentation at
950L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> 1137L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
951for more details. 1138(locally installed as F<EV::libev>) for more details.
952 1139
953In short, this watcher is most useful on BSD systems without working 1140In short, this watcher is most useful on BSD systems without working
954kqueue to still be able to handle a large number of sockets: 1141kqueue to still be able to handle a large number of sockets:
955 1142
956 my $socket_loop; 1143 my $socket_loop;
957 1144
958 # check wether we use SELECT or POLL _and_ KQUEUE is supported 1145 # check wether we use SELECT or POLL _and_ KQUEUE is supported
959 if ( 1146 if (
960 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 1147 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
961 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 1148 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
962 ) { 1149 ) {
963 # use kqueue for sockets 1150 # use kqueue for sockets
964 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 1151 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
965 } 1152 }
966 1153
967 # use the default loop otherwise 1154 # use the default loop otherwise
968 $socket_loop ||= EV::default_loop; 1155 $socket_loop ||= EV::default_loop;
969 1156
970=over 4 1157=over 4
971 1158
972=item $w = EV::embed $otherloop, $callback 1159=item $w = EV::embed $otherloop[, $callback]
973 1160
974=item $w = EV::embed_ns $otherloop, $callback 1161=item $w = EV::embed_ns $otherloop[, $callback]
975 1162
976=item $w = $loop->embed ($otherloop, $callback) 1163=item $w = $loop->embed ($otherloop[, $callback])
977 1164
978=item $w = $loop->embed_ns ($otherloop, $callback) 1165=item $w = $loop->embed_ns ($otherloop[, $callback])
979 1166
980Call the callback when the embedded event loop (C<$otherloop>) has any 1167Call the callback when the embedded event loop (C<$otherloop>) has any
981I/O activity. The C<$callback> should alwas be specified as C<undef> in 1168I/O activity. The C<$callback> is optional: if it is missing, then the
982this version of EV, which means the embedded event loop will be managed 1169embedded event loop will be managed automatically (which is recommended),
983automatically. 1170otherwise you have to invoke C<sweep> yourself.
984 1171
985The C<embed_ns> variant doesn't start (activate) the newly created watcher. 1172The C<embed_ns> variant doesn't start (activate) the newly created watcher.
986 1173
987=back 1174=back
988 1175
989=head3 ASYNC WATCHERS - how to wake up another event loop 1176=head3 ASYNC WATCHERS - how to wake up another event loop
990 1177
991Async watchers are provided by EV, but have little use in perl directly, as perl 1178Async watchers are provided by EV, but have little use in perl directly,
992neither supports threads nor direct access to signal handlers or other 1179as perl neither supports threads running in parallel nor direct access to
993contexts where they could be of value. 1180signal handlers or other contexts where they could be of value.
994 1181
995It is, however, possible to use them from the XS level. 1182It is, however, possible to use them from the XS level.
996 1183
997Please see the libev documentation for further details. 1184Please see the libev documentation for further details.
998 1185
… …
1000 1187
1001=item $w = EV::async $callback 1188=item $w = EV::async $callback
1002 1189
1003=item $w = EV::async_ns $callback 1190=item $w = EV::async_ns $callback
1004 1191
1192=item $w = $loop->async ($callback)
1193
1194=item $w = $loop->async_ns ($callback)
1195
1005=item $w->send 1196=item $w->send
1006 1197
1007=item $bool = $w->async_pending 1198=item $bool = $w->async_pending
1008 1199
1009=back 1200=back
1201
1202=head3 CLEANUP WATCHERS - how to clean up when the event loop goes away
1203
1204Cleanup watchers are not supported on the Perl level, they can only be
1205used via XS currently.
1010 1206
1011 1207
1012=head1 PERL SIGNALS 1208=head1 PERL SIGNALS
1013 1209
1014While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour 1210While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
… …
1026 my $async_check = EV::check sub { }; 1222 my $async_check = EV::check sub { };
1027 1223
1028This ensures that perl gets into control for a short time to handle any 1224This ensures that perl gets into control for a short time to handle any
1029pending signals, and also ensures (slightly) slower overall operation. 1225pending signals, and also ensures (slightly) slower overall operation.
1030 1226
1031=head1 THREADS 1227=head1 ITHREADS
1032 1228
1033Threads are not supported by this module in any way. Perl pseudo-threads 1229Ithreads are not supported by this module in any way. Perl pseudo-threads
1034is evil stuff and must die. As soon as Perl gains real threads I will work 1230is evil stuff and must die. Real threads as provided by Coro are fully
1035on thread support for it. 1231supported (and enhanced support is available via L<Coro::EV>).
1036 1232
1037=head1 FORK 1233=head1 FORK
1038 1234
1039Most of the "improved" event delivering mechanisms of modern operating 1235Most of the "improved" event delivering mechanisms of modern operating
1040systems have quite a few problems with fork(2) (to put it bluntly: it is 1236systems have quite a few problems with fork(2) (to put it bluntly: it is
… …
1062 1258
10631; 12591;
1064 1260
1065=head1 SEE ALSO 1261=head1 SEE ALSO
1066 1262
1263L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS>
1067L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as 1264(asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as event
1068event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient 1265loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient thread
1069coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for 1266integration), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1070event-loop agnostic and portable event driven programming. 1267event-loop agnostic and portable event driven programming.
1071 1268
1072=head1 AUTHOR 1269=head1 AUTHOR
1073 1270
1074 Marc Lehmann <schmorp@schmorp.de> 1271 Marc Lehmann <schmorp@schmorp.de>
1075 http://home.schmorp.de/ 1272 http://home.schmorp.de/
1076 1273
1077=cut 1274=cut
1078 1275

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