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Revision 1.93 by root, Tue May 20 19:52:12 2008 UTC vs.
Revision 1.151 by root, Tue Sep 4 23:14:45 2018 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 = '3.4'; 124 our $VERSION = 4.22;
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 fucntion automatically, at some performance loss (refer to the libev 189this function automatically, at some performance loss (refer to the libev
136documentation). 190documentation).
137 191
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
138=item $loop = EV::default_loop [$flags] 198=item $loop = EV::default_loop [$flags]
139 199
140Return 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.
141 205
142=back 206=back
143 207
144 208
145=head1 BASIC INTERFACE 209=head1 BASIC INTERFACE
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175=item $time = EV::now 239=item $time = EV::now
176 240
177=item $time = $loop->now 241=item $time = $loop->now
178 242
179Returns the time the last event loop iteration has been started. This 243Returns the time the last event loop iteration has been started. This
180is 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
181usually faster then calling EV::time. 245usually faster then calling EV::time.
182 246
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::loop>.
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
183=item $backend = EV::backend 289=item $backend = EV::backend
184 290
185=item $backend = $loop->backend 291=item $backend = $loop->backend
186 292
187Returns an integer describing the backend used by libev (EV::METHOD_SELECT 293Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
188or EV::METHOD_EPOLL). 294or EV::BACKEND_EPOLL).
189 295
190=item EV::loop [$flags] 296=item $active = EV::run [$flags]
191 297
192=item $loop->loop ([$flags]) 298=item $active = $loop->run ([$flags])
193 299
194Begin checking for events and calling callbacks. It returns when a 300Begin checking for events and calling callbacks. It returns when a
195callback 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".
196 306
197The $flags argument can be one of the following: 307The $flags argument can be one of the following:
198 308
199 0 as above 309 0 as above
200 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 310 EV::RUN_ONCE block at most once (wait, but do not loop)
201 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 311 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
202 312
203=item EV::unloop [$how] 313=item EV::break [$how]
204 314
205=item $loop->unloop ([$how]) 315=item $loop->break ([$how])
206 316
207When 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
208innermost call to EV::loop return. 318innermost call to EV::loop return.
209 319
210When 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::loop will
211fast as possible. 321return as fast as possible.
212 322
213=item $count = EV::loop_count 323When called with an argument of EV::BREAK_CANCEL, any pending break will
324be cancelled.
214 325
326=item $count = EV::iteration
327
215=item $count = $loop->loop_count 328=item $count = $loop->iteration
216 329
217Return the number of times the event loop has polled for new 330Return the number of times the event loop has polled for new
218events. Sometiems useful as a generation counter. 331events. Sometimes useful as a generation counter.
219 332
220=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 333=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
221 334
222=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 335=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
223 336
… …
234timeout. Otherwise a EV::timer with this value will be started. 347timeout. Otherwise a EV::timer with this value will be started.
235 348
236When 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
237the callback will be called with the received event set (in general 350the callback will be called with the received event set (in general
238you 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>,
239C<EV::WRITE> and C<EV::TIMEOUT>). 352C<EV::WRITE> and C<EV::TIMER>).
240 353
241EV::once doesn't return anything: the watchers stay active till either 354EV::once doesn't return anything: the watchers stay active till either
242of 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
243invoked. 356invoked.
244 357
245=item EV::feed_fd_event ($fd, $revents) 358=item EV::feed_fd_event $fd, $revents
246 359
247=item $loop->feed_fd_event ($fd, $revents) 360=item $loop->feed_fd_event ($fd, $revents)
248 361
249Feed an event on a file descriptor into EV. EV will react to this call as 362Feed an event on a file descriptor into EV. EV will react to this call as
250if the readyness notifications specified by C<$revents> (a combination of 363if the readyness notifications specified by C<$revents> (a combination of
251C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. 364C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
252 365
253=item EV::feed_signal_event ($signal) 366=item EV::feed_signal_event $signal
254 367
255Feed a signal event into EV. EV will react to this call as if the signal 368Feed a signal event into the default loop. EV will react to this call as
256specified by C<$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
375fro custom signal implementations.
257 376
258=item EV::set_io_collect_interval $time 377=item EV::set_io_collect_interval $time
259 378
260=item $loop->set_io_collect_interval ($time) 379=item $loop->set_io_collect_interval ($time)
261 380
… …
263 382
264=item $loop->set_timeout_collect_interval ($time) 383=item $loop->set_timeout_collect_interval ($time)
265 384
266These 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
267wait interval for timer events. See the libev documentation at 386wait interval for timer events. See the libev documentation at
268L<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>
269a 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.
270 401
271=back 402=back
272 403
273 404
274=head1 WATCHER OBJECTS 405=head1 WATCHER OBJECTS
275 406
276A 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
277event. 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
278would create an EV::io watcher for that: 409would create an EV::io watcher for that:
279 410
280 my $watcher = EV::io *STDIN, EV::READ, sub { 411 my $watcher = EV::io *STDIN, EV::READ, sub {
281 my ($watcher, $revents) = @_; 412 my ($watcher, $revents) = @_;
282 warn "yeah, STDIN should now be readable without blocking!\n" 413 warn "yeah, STDIN should now be readable without blocking!\n"
283 }; 414 };
284 415
285All watchers can be active (waiting for events) or inactive (paused). Only 416All watchers can be active (waiting for events) or inactive (paused). Only
286active watchers will have their callbacks invoked. All callbacks will be 417active watchers will have their callbacks invoked. All callbacks will be
287called 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
288events. 419events.
289 420
290Each 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
291same callback for multiple watchers. The event mask is named after the 422same callback for multiple watchers. The event mask is named after the
292type, 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,
293EV::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
294(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).
295uses EV::TIMEOUT).
296 426
297In 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
298the 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
299its 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.
300 430
… …
379 509
380=item $previous_state = $w->keepalive ($bool) 510=item $previous_state = $w->keepalive ($bool)
381 511
382Normally, C<EV::loop> will return when there are no active watchers 512Normally, C<EV::loop> will return when there are no active watchers
383(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
384convinient because it allows you to start your watchers (and your jobs), 514convenient because it allows you to start your watchers (and your jobs),
385call C<EV::loop> once and when it returns you know that all your jobs are 515call C<EV::loop> once and when it returns you know that all your jobs are
386finished (or they forgot to register some watchers for their task :). 516finished (or they forgot to register some watchers for their task :).
387 517
388Sometimes, however, this gets in your way, for example when the module 518Sometimes, however, this gets in your way, for example when the module
389that calls C<EV::loop> (usually the main program) is not the same module 519that calls C<EV::loop> (usually the main program) is not the same module
… …
393because you happen to have this long-running UDP port watcher. 523because you happen to have this long-running UDP port watcher.
394 524
395In 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
396though your watcher is active, it won't keep C<EV::loop> from returning. 526though your watcher is active, it won't keep C<EV::loop> from returning.
397 527
398The 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
399any time. 529any time.
400 530
401Example: 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
402event loop from running just because of that watcher. 532event loop from running just because of that watcher.
403 533
404 my $udp_socket = ... 534 my $udp_socket = ...
405 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 535 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
406 $1000udp_watcher->keepalive (0); 536 $udp_watcher->keepalive (0);
407 537
408=item $loop = $w->loop 538=item $loop = $w->loop
409 539
410Return the loop that this watcher is attached to. 540Return the loop that this watcher is attached to.
411 541
… …
468 598
469=item $w = $loop->timer ($after, $repeat, $callback) 599=item $w = $loop->timer ($after, $repeat, $callback)
470 600
471=item $w = $loop->timer_ns ($after, $repeat, $callback) 601=item $w = $loop->timer_ns ($after, $repeat, $callback)
472 602
473Calls the callback after C<$after> seconds (which may be fractional). If 603Calls the callback after C<$after> seconds (which may be fractional or
474C<$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
475value as $after) after the callback returns. 605the $repeat value as $after) after the callback returns.
476 606
477This means that the callback would be called roughly after C<$after> 607This means that the callback would be called roughly after C<$after>
478seconds, and then every C<$repeat> seconds. The timer does his best not 608seconds, and then every C<$repeat> seconds. The timer does his best not
479to 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
480loop 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,
… …
484in 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
485clock, the timer will nevertheless run (roughly) the same time. 615clock, the timer will nevertheless run (roughly) the same time.
486 616
487The 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.
488 618
489=item $w->set ($after, $repeat) 619=item $w->set ($after, $repeat = 0)
490 620
491Reconfigures 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
492any time. 622any time.
493 623
494=item $w->again 624=item $w->again
625
626=item $w->again ($repeat)
495 627
496Similar 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:
497 629
498If the timer is active and non-repeating, it will be stopped. 630If the timer is active and non-repeating, it will be stopped.
499 631
… …
506 638
507This behaviour is useful when you have a timeout for some IO 639This behaviour is useful when you have a timeout for some IO
508operation. 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
509C<$repeat>, and then, in the read/write watcher, run the C<again> method 641C<$repeat>, and then, in the read/write watcher, run the C<again> method
510on 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 = $w->remaining
648
649Calculates and returns the remaining time till the timer will fire.
511 650
512=back 651=back
513 652
514 653
515=head3 PERIODIC WATCHERS - to cron or not to cron? 654=head3 PERIODIC WATCHERS - to cron or not to cron?
… …
543surpasses this time. 682surpasses this time.
544 683
545=item * repeating interval timer ($interval > 0, $reschedule_cb = 0) 684=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
546 685
547In this mode the watcher will always be scheduled to time out at the 686In this mode the watcher will always be scheduled to time out at the
548next C<$at + N * $interval> time (for some integer N) and then repeat, 687next C<$at + N * $interval> time (for the lowest integer N) and then repeat,
549regardless of any time jumps. 688regardless of any time jumps. Note that, since C<N> can be negative, the
689first trigger can happen before C<$at>.
550 690
551This 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
552time: 692time:
553 693
554 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; 694 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
555 695
556That doesn't mean there will always be 3600 seconds in between triggers, 696That doesn't mean there will always be 3600 seconds in between triggers,
557but only that the the clalback will be called when the system time shows a 697but only that the the callback will be called when the system time shows a
558full hour (UTC). 698full hour (UTC).
559 699
560Another way to think about it (for the mathematically inclined) is that 700Another way to think about it (for the mathematically inclined) is that
561EV::periodic will try to run the callback in this mode at the next 701EV::periodic will try to run the callback in this mode at the next
562possible time where C<$time = $at (mod $interval)>, regardless of any time 702possible time where C<$time = $at (mod $interval)>, regardless of any time
… …
568time the periodic watcher gets scheduled, the reschedule callback 708time the periodic watcher gets scheduled, the reschedule callback
569($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
570time as second argument. 710time as second argument.
571 711
572I<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
573watcher, 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
574afterwards. 714you need to stop it, return 1e30 and stop it afterwards. You may create
715and start a C<EV::prepare> watcher for this task.
575 716
576It 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
577(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
578will usually be called just before the callback will be triggered, but 719argument). It will usually be called just before the callback will be
579might be called at other times, too. 720triggered, but might be called at other times, too.
580 721
581This 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
582triggers on each midnight, local time (actually 24 hours after the last 723triggers on each midnight, local time (actually 24 hours after the last
583midnight, to keep the example simple. If you know a way to do it correctly 724midnight, to keep the example simple. If you know a way to do it correctly
584in about the same space (without requiring elaborate modules), drop me a 725in about the same space (without requiring elaborate modules), drop me a
… …
620 761
621=item $w = EV::signal $signal, $callback 762=item $w = EV::signal $signal, $callback
622 763
623=item $w = EV::signal_ns $signal, $callback 764=item $w = EV::signal_ns $signal, $callback
624 765
766=item $w = $loop->signal ($signal, $callback)
767
768=item $w = $loop->signal_ns ($signal, $callback)
769
625Call the callback when $signal is received (the signal can be specified by 770Call the callback when $signal is received (the signal can be specified by
626number or by name, just as with C<kill> or C<%SIG>). 771number or by name, just as with C<kill> or C<%SIG>).
772
773Only one event loop can grab a given signal - attempting to grab the same
774signal from two EV loops will crash the program immediately or cause data
775corruption.
627 776
628EV will grab the signal for the process (the kernel only allows one 777EV will grab the signal for the process (the kernel only allows one
629component to receive a signal at a time) when you start a signal watcher, 778component to receive a signal at a time) when you start a signal watcher,
630and removes it again when you stop it. Perl does the same when you 779and removes it again when you stop it. Perl does the same when you
631add/remove callbacks to C<%SIG>, so watch out. 780add/remove callbacks to C<%SIG>, so watch out.
… …
856=item $w = $loop->check_ns ($callback) 1005=item $w = $loop->check_ns ($callback)
857 1006
858Call the callback just after the process wakes up again (after it has 1007Call the callback just after the process wakes up again (after it has
859gathered events), but before any other callbacks have been invoked. 1008gathered events), but before any other callbacks have been invoked.
860 1009
861This is used to integrate other event-based software into the EV 1010This can be used to integrate other event-based software into the EV
862mainloop: You register a prepare callback and in there, you create io and 1011mainloop: You register a prepare callback and in there, you create io and
863timer watchers as required by the other software. Here is a real-world 1012timer watchers as required by the other software. Here is a real-world
864example of integrating Net::SNMP (with some details left out): 1013example of integrating Net::SNMP (with some details left out):
865 1014
866 our @snmp_watcher; 1015 our @snmp_watcher;
… …
896 # make the dispatcher handle any new stuff 1045 # make the dispatcher handle any new stuff
897 ... not shown 1046 ... not shown
898 }; 1047 };
899 1048
900The callbacks of the created watchers will not be called as the watchers 1049The callbacks of the created watchers will not be called as the watchers
901are destroyed before this cna happen (remember EV::check gets called 1050are destroyed before this can happen (remember EV::check gets called
902first). 1051first).
903 1052
904The C<check_ns> variant doesn't start (activate) the newly created watcher. 1053The C<check_ns> variant doesn't start (activate) the newly created watcher.
1054
1055=item EV::CHECK constant issues
1056
1057Like all other watcher types, there is a bitmask constant for use in
1058C<$revents> and other places. The C<EV::CHECK> is special as it has
1059the same name as the C<CHECK> sub called by Perl. This doesn't cause
1060big issues on newer perls (beginning with 5.8.9), but it means thatthe
1061constant must be I<inlined>, i.e. runtime calls will not work. That means
1062that as long as you always C<use EV> and then C<EV::CHECK> you are on the
1063safe side.
905 1064
906=back 1065=back
907 1066
908 1067
909=head3 FORK WATCHERS - the audacity to resume the event loop after a fork 1068=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
… …
937loop, other types of watchers might be handled in a delayed or incorrect 1096loop, other types of watchers might be handled in a delayed or incorrect
938fashion and must not be used). 1097fashion and must not be used).
939 1098
940See the libev documentation at 1099See the libev documentation at
941L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> 1100L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
942for more details. 1101(locally installed as F<EV::libev>) for more details.
943 1102
944In short, this watcher is most useful on BSD systems without working 1103In short, this watcher is most useful on BSD systems without working
945kqueue to still be able to handle a large number of sockets: 1104kqueue to still be able to handle a large number of sockets:
946 1105
947 my $socket_loop; 1106 my $socket_loop;
948 1107
949 # check wether we use SELECT or POLL _and_ KQUEUE is supported 1108 # check wether we use SELECT or POLL _and_ KQUEUE is supported
950 if ( 1109 if (
951 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 1110 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
952 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 1111 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
953 ) { 1112 ) {
954 # use kqueue for sockets 1113 # use kqueue for sockets
955 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 1114 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
956 } 1115 }
957 1116
958 # use the default loop otherwise 1117 # use the default loop otherwise
959 $socket_loop ||= EV::default_loop; 1118 $socket_loop ||= EV::default_loop;
960 1119
961=over 4 1120=over 4
962 1121
963=item $w = EV::embed $otherloop, $callback 1122=item $w = EV::embed $otherloop[, $callback]
964 1123
965=item $w = EV::embed_ns $otherloop, $callback 1124=item $w = EV::embed_ns $otherloop[, $callback]
966 1125
967=item $w = $loop->embed ($otherloop, $callback) 1126=item $w = $loop->embed ($otherloop[, $callback])
968 1127
969=item $w = $loop->embed_ns ($otherloop, $callback) 1128=item $w = $loop->embed_ns ($otherloop[, $callback])
970 1129
971Call the callback when the embedded event loop (C<$otherloop>) has any 1130Call the callback when the embedded event loop (C<$otherloop>) has any
972I/O activity. The C<$callback> should alwas be specified as C<undef> in 1131I/O activity. The C<$callback> is optional: if it is missing, then the
973this version of EV, which means the embedded event loop will be managed 1132embedded event loop will be managed automatically (which is recommended),
974automatically. 1133otherwise you have to invoke C<sweep> yourself.
975 1134
976The C<embed_ns> variant doesn't start (activate) the newly created watcher. 1135The C<embed_ns> variant doesn't start (activate) the newly created watcher.
977 1136
978=back 1137=back
979 1138
980=head3 ASYNC WATCHERS - how to wake up another event loop 1139=head3 ASYNC WATCHERS - how to wake up another event loop
981 1140
982Async watchers are provided by EV, but have little use in perl directly, as perl 1141Async watchers are provided by EV, but have little use in perl directly,
983neither supports threads nor direct access to signal handlers or other 1142as perl neither supports threads running in parallel nor direct access to
984contexts where they could be of value. 1143signal handlers or other contexts where they could be of value.
985 1144
986It is, however, possible to use them from the XS level. 1145It is, however, possible to use them from the XS level.
987 1146
988Please see the libev documentation for further details. 1147Please see the libev documentation for further details.
989 1148
… …
991 1150
992=item $w = EV::async $callback 1151=item $w = EV::async $callback
993 1152
994=item $w = EV::async_ns $callback 1153=item $w = EV::async_ns $callback
995 1154
1155=item $w = $loop->async ($callback)
1156
1157=item $w = $loop->async_ns ($callback)
1158
996=item $w->send 1159=item $w->send
997 1160
998=item $bool = $w->async_pending 1161=item $bool = $w->async_pending
999 1162
1000=back 1163=back
1164
1165=head3 CLEANUP WATCHERS - how to clean up when the event loop goes away
1166
1167Cleanup watchers are not supported on the Perl level, they can only be
1168used via XS currently.
1001 1169
1002 1170
1003=head1 PERL SIGNALS 1171=head1 PERL SIGNALS
1004 1172
1005While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour 1173While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
… …
1017 my $async_check = EV::check sub { }; 1185 my $async_check = EV::check sub { };
1018 1186
1019This ensures that perl gets into control for a short time to handle any 1187This ensures that perl gets into control for a short time to handle any
1020pending signals, and also ensures (slightly) slower overall operation. 1188pending signals, and also ensures (slightly) slower overall operation.
1021 1189
1022=head1 THREADS 1190=head1 ITHREADS
1023 1191
1024Threads are not supported by this module in any way. Perl pseudo-threads 1192Ithreads are not supported by this module in any way. Perl pseudo-threads
1025is evil stuff and must die. As soon as Perl gains real threads I will work 1193is evil stuff and must die. Real threads as provided by Coro are fully
1026on thread support for it. 1194supported (and enhanced support is available via L<Coro::EV>).
1027 1195
1028=head1 FORK 1196=head1 FORK
1029 1197
1030Most of the "improved" event delivering mechanisms of modern operating 1198Most of the "improved" event delivering mechanisms of modern operating
1031systems have quite a few problems with fork(2) (to put it bluntly: it is 1199systems have quite a few problems with fork(2) (to put it bluntly: it is
… …
1053 1221
10541; 12221;
1055 1223
1056=head1 SEE ALSO 1224=head1 SEE ALSO
1057 1225
1226L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS>
1058L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as 1227(asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as event
1059event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient 1228loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient thread
1060coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for 1229integration), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1061event-loop agnostic and portable event driven programming. 1230event-loop agnostic and portable event driven programming.
1062 1231
1063=head1 AUTHOR 1232=head1 AUTHOR
1064 1233
1065 Marc Lehmann <schmorp@schmorp.de> 1234 Marc Lehmann <schmorp@schmorp.de>
1066 http://home.schmorp.de/ 1235 http://home.schmorp.de/
1067 1236
1068=cut 1237=cut
1069 1238

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