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Revision 1.62 by root, Fri Dec 7 18:09:38 2007 UTC vs.
Revision 1.152 by root, Sun Oct 28 23:40:32 2018 UTC

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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 = '1.7'; 124 our $VERSION = 4.22;
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
144@EV::Loop::Default::ISA = "EV::Loop";
145
146=head1 EVENT LOOPS
147
148EV supports multiple event loops: There is a single "default event loop"
149that can handle everything including signals and child watchers, and any
150number of "dynamic event loops" that can use different backends (with
151various limitations), but no child and signal watchers.
152
153You do not have to do anything to create the default event loop: When
154the module is loaded a suitable backend is selected on the premise of
155selecting a working backend (which for example rules out kqueue on most
156BSDs). Modules should, unless they have "special needs" always use the
157default loop as this is fastest (perl-wise), best supported by other
158modules (e.g. AnyEvent or Coro) and most portable event loop.
159
160For specific programs you can create additional event loops dynamically.
161
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.
167
168=over 4
169
170=item $loop = new EV::Loop [$flags]
171
172Create a new event loop as per the specified flags. Please refer to
173the C<ev_loop_new ()> function description in the libev documentation
174(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
175or locally-installed as F<EV::libev> manpage) for more info.
176
177The loop will automatically be destroyed when it is no longer referenced
178by any watcher and the loop object goes out of scope.
179
180If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
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.
184
185=item $loop->loop_fork
186
187Must be called after a fork in the child, before entering or continuing
188the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
189this function automatically, at some performance loss (refer to the libev
190documentation).
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
198=item $loop = EV::default_loop [$flags]
199
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.
205
206=back
207
208
91=head1 BASIC INTERFACE 209=head1 BASIC INTERFACE
92 210
93=over 4 211=over 4
94 212
95=item $EV::DIED 213=item $EV::DIED
96 214
97Must contain a reference to a function that is called when a callback 215Must contain a reference to a function that is called when a callback
98throws an exception (with $@ containing thr error). The default prints an 216throws an exception (with $@ containing the error). The default prints an
99informative message and continues. 217informative message and continues.
100 218
101If this callback throws an exception it will be silently ignored. 219If this callback throws an exception it will be silently ignored.
102 220
221=item $flags = EV::supported_backends
222
223=item $flags = EV::recommended_backends
224
225=item $flags = EV::embeddable_backends
226
227Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
228instance of EV, the set of recommended backends (supposed to be good) for
229this platform and the set of embeddable backends (see EMBED WATCHERS).
230
231=item EV::sleep $seconds
232
233Block the process for the given number of (fractional) seconds.
234
103=item $time = EV::time 235=item $time = EV::time
104 236
105Returns the current time in (fractional) seconds since the epoch. 237Returns the current time in (fractional) seconds since the epoch.
106 238
107=item $time = EV::now 239=item $time = EV::now
108 240
241=item $time = $loop->now
242
109Returns the time the last event loop iteration has been started. This 243Returns the time the last event loop iteration has been started. This
110is 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
111usually faster then calling EV::time. 245usually faster then calling EV::time.
112 246
113=item $method = EV::method 247=item EV::now_update
114 248
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
289=item $backend = EV::backend
290
291=item $backend = $loop->backend
292
115Returns an integer describing the backend used by libev (EV::METHOD_SELECT 293Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
116or EV::METHOD_EPOLL). 294or EV::BACKEND_EPOLL).
117 295
118=item EV::loop [$flags] 296=item $active = EV::run [$flags]
297
298=item $active = $loop->run ([$flags])
119 299
120Begin checking for events and calling callbacks. It returns when a 300Begin checking for events and calling callbacks. It returns when a
121callback 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".
122 306
123The $flags argument can be one of the following: 307The $flags argument can be one of the following:
124 308
125 0 as above 309 0 as above
126 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 310 EV::RUN_ONCE block at most once (wait, but do not loop)
127 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 311 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
128 312
129=item EV::unloop [$how] 313=item EV::break [$how]
130 314
315=item $loop->break ([$how])
316
131When 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
132innermost call to EV::loop return. 318innermost call to EV::loop return.
133 319
134When 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
135fast as possible. 321return as fast as possible.
136 322
137=item $count = EV::loop_count 323When called with an argument of EV::BREAK_CANCEL, any pending break will
324be cancelled.
325
326=item $count = EV::iteration
327
328=item $count = $loop->iteration
138 329
139Return the number of times the event loop has polled for new 330Return the number of times the event loop has polled for new
140events. Sometiems useful as a generation counter. 331events. Sometimes useful as a generation counter.
141 332
142=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 333=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
334
335=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
143 336
144This function rolls together an I/O and a timer watcher for a single 337This function rolls together an I/O and a timer watcher for a single
145one-shot event without the need for managing a watcher object. 338one-shot event without the need for managing a watcher object.
146 339
147If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> 340If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
… …
153If timeout is C<undef> or negative, then there will be no 346If timeout is C<undef> or negative, then there will be no
154timeout. Otherwise a EV::timer with this value will be started. 347timeout. Otherwise a EV::timer with this value will be started.
155 348
156When 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
157the callback will be called with the received event set (in general 350the callback will be called with the received event set (in general
158you 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>,
159C<EV::WRITE> and C<EV::TIMEOUT>). 352C<EV::WRITE> and C<EV::TIMER>).
160 353
161EV::once doesn't return anything: the watchers stay active till either 354EV::once doesn't return anything: the watchers stay active till either
162of 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
163invoked. 356invoked.
164 357
165=back 358=item EV::feed_fd_event $fd, $revents
166 359
360=item $loop->feed_fd_event ($fd, $revents)
361
362Feed an event on a file descriptor into EV. EV will react to this call as
363if the readyness notifications specified by C<$revents> (a combination of
364C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
365
366=item EV::feed_signal_event $signal
367
368Feed a signal event into the default loop. EV will react to this call as
369if the signal specified by C<$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.
376
377=item EV::set_io_collect_interval $time
378
379=item $loop->set_io_collect_interval ($time)
380
381=item EV::set_timeout_collect_interval $time
382
383=item $loop->set_timeout_collect_interval ($time)
384
385These advanced functions set the minimum block interval when polling for I/O events and the minimum
386wait interval for timer events. See the libev documentation at
387L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
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.
401
402=back
403
404
167=head2 WATCHER OBJECTS 405=head1 WATCHER OBJECTS
168 406
169A 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
170event. 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
171would create an EV::io watcher for that: 409would create an EV::io watcher for that:
172 410
173 my $watcher = EV::io *STDIN, EV::READ, sub { 411 my $watcher = EV::io *STDIN, EV::READ, sub {
174 my ($watcher, $revents) = @_; 412 my ($watcher, $revents) = @_;
175 warn "yeah, STDIN should not be readable without blocking!\n" 413 warn "yeah, STDIN should now be readable without blocking!\n"
176 }; 414 };
177 415
178All watchers can be active (waiting for events) or inactive (paused). Only 416All watchers can be active (waiting for events) or inactive (paused). Only
179active watchers will have their callbacks invoked. All callbacks will be 417active watchers will have their callbacks invoked. All callbacks will be
180called 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
181events. 419events.
182 420
183Each 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
184same callback for multiple watchers. The event mask is named after the 422same callback for multiple watchers. The event mask is named after the
185type, 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,
186EV::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
187(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).
188uses EV::TIMEOUT).
189 426
190In 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
191the 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
192its 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.
193 430
… …
253The default priority of any newly-created watcher is 0. 490The default priority of any newly-created watcher is 0.
254 491
255Note that the priority semantics have not yet been fleshed out and are 492Note that the priority semantics have not yet been fleshed out and are
256subject to almost certain change. 493subject to almost certain change.
257 494
258=item $w->trigger ($revents) 495=item $w->invoke ($revents)
259 496
260Call the callback *now* with the given event mask. 497Call the callback *now* with the given event mask.
498
499=item $w->feed_event ($revents)
500
501Feed some events on this watcher into EV. EV will react to this call as if
502the watcher had received the given C<$revents> mask.
503
504=item $revents = $w->clear_pending
505
506If the watcher is pending, this function clears its pending status and
507returns its C<$revents> bitset (as if its callback was invoked). If the
508watcher isn't pending it does nothing and returns C<0>.
261 509
262=item $previous_state = $w->keepalive ($bool) 510=item $previous_state = $w->keepalive ($bool)
263 511
264Normally, C<EV::loop> will return when there are no active watchers 512Normally, C<EV::loop> will return when there are no active watchers
265(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
266convinient because it allows you to start your watchers (and your jobs), 514convenient because it allows you to start your watchers (and your jobs),
267call 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
268finished (or they forgot to register some watchers for their task :). 516finished (or they forgot to register some watchers for their task :).
269 517
270Sometimes, however, this gets in your way, for example when you the module 518Sometimes, however, this gets in your way, for example when the module
271that 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
272as 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
273somebody else even). Then you might want any outstanding requests to be 521somebody else even). Then you might want any outstanding requests to be
274handled, but you would not want to keep C<EV::loop> from returning just 522handled, but you would not want to keep C<EV::loop> from returning just
275because you happen to have this long-running UDP port watcher. 523because you happen to have this long-running UDP port watcher.
276 524
277In 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
278though 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.
279 527
280The 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
281any time. 529any time.
282 530
283Example: 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
284event loop from running just because of that watcher. 532event loop from running just because of that watcher.
285 533
286 my $udp_socket = ... 534 my $udp_socket = ...
287 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 535 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
288 $udp_watcher->keepalive (0); 536 $udp_watcher->keepalive (0);
289 537
290=back 538=item $loop = $w->loop
291 539
540Return the loop that this watcher is attached to.
292 541
542=back
543
544
293=head2 WATCHER TYPES 545=head1 WATCHER TYPES
294 546
295Each of the following subsections describes a single watcher type. 547Each of the following subsections describes a single watcher type.
296 548
297=head3 I/O WATCHERS - is this file descriptor readable or writable? 549=head3 I/O WATCHERS - is this file descriptor readable or writable?
298 550
299=over 4 551=over 4
300 552
301=item $w = EV::io $fileno_or_fh, $eventmask, $callback 553=item $w = EV::io $fileno_or_fh, $eventmask, $callback
302 554
303=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 555=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
556
557=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
558
559=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
304 560
305As long as the returned watcher object is alive, call the C<$callback> 561As long as the returned watcher object is alive, call the C<$callback>
306when at least one of events specified in C<$eventmask> occurs. 562when at least one of events specified in C<$eventmask> occurs.
307 563
308The $eventmask can be one or more of these constants ORed together: 564The $eventmask can be one or more of these constants ORed together:
… …
338 594
339=item $w = EV::timer $after, $repeat, $callback 595=item $w = EV::timer $after, $repeat, $callback
340 596
341=item $w = EV::timer_ns $after, $repeat, $callback 597=item $w = EV::timer_ns $after, $repeat, $callback
342 598
599=item $w = $loop->timer ($after, $repeat, $callback)
600
601=item $w = $loop->timer_ns ($after, $repeat, $callback)
602
343Calls the callback after C<$after> seconds (which may be fractional). If 603Calls the callback after C<$after> seconds (which may be fractional or
344C<$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
345value as $after) after the callback returns. 605the $repeat value as $after) after the callback returns.
346 606
347This means that the callback would be called roughly after C<$after> 607This means that the callback would be called roughly after C<$after>
348seconds, and then every C<$repeat> seconds. The timer does his best not 608seconds, and then every C<$repeat> seconds. The timer does his best not
349to 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
350loop 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,
… …
354in 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
355clock, the timer will nevertheless run (roughly) the same time. 615clock, the timer will nevertheless run (roughly) the same time.
356 616
357The 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.
358 618
359=item $w->set ($after, $repeat) 619=item $w->set ($after, $repeat = 0)
360 620
361Reconfigures 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
362any time. 622any time.
363 623
364=item $w->again 624=item $w->again
625
626=item $w->again ($repeat)
365 627
366Similar 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:
367 629
368If the timer is active and non-repeating, it will be stopped. 630If the timer is active and non-repeating, it will be stopped.
369 631
… …
377This behaviour is useful when you have a timeout for some IO 639This behaviour is useful when you have a timeout for some IO
378operation. 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
379C<$repeat>, and then, in the read/write watcher, run the C<again> method 641C<$repeat>, and then, in the read/write watcher, run the C<again> method
380on the timeout. 642on the timeout.
381 643
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
382=back 651=back
383 652
384 653
385=head3 PERIODIC WATCHERS - to cron or not to cron? 654=head3 PERIODIC WATCHERS - to cron or not to cron?
386 655
387=over 4 656=over 4
388 657
389=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback 658=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
390 659
391=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 660=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
661
662=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
663
664=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
392 665
393Similar to EV::timer, but is not based on relative timeouts but on 666Similar to EV::timer, but is not based on relative timeouts but on
394absolute times. Apart from creating "simple" timers that trigger "at" the 667absolute times. Apart from creating "simple" timers that trigger "at" the
395specified time, it can also be used for non-drifting absolute timers and 668specified time, it can also be used for non-drifting absolute timers and
396more complex, cron-like, setups that are not adversely affected by time 669more complex, cron-like, setups that are not adversely affected by time
… …
406This time simply fires at the wallclock time C<$at> and doesn't repeat. It 679This time simply fires at the wallclock time C<$at> and doesn't repeat. It
407will not adjust when a time jump occurs, that is, if it is to be run 680will not adjust when a time jump occurs, that is, if it is to be run
408at January 1st 2011 then it will run when the system time reaches or 681at January 1st 2011 then it will run when the system time reaches or
409surpasses this time. 682surpasses this time.
410 683
411=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 684=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
412 685
413In this mode the watcher will always be scheduled to time out at the 686In this mode the watcher will always be scheduled to time out at the
414next C<$at + N * $interval> time (for some integer N) and then repeat, 687next C<$at + N * $interval> time (for the lowest integer N) and then repeat,
415regardless of any time jumps. 688regardless of any time jumps. Note that, since C<N> can be negative, the
689first trigger can happen before C<$at>.
416 690
417This 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
418time: 692time:
419 693
420 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; 694 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
421 695
422That doesn't mean there will always be 3600 seconds in between triggers, 696That doesn't mean there will always be 3600 seconds in between triggers,
423but only that the the clalback will be called when the system time shows a 697but only that the the callback will be called when the system time shows a
424full hour (UTC). 698full hour (UTC).
425 699
426Another way to think about it (for the mathematically inclined) is that 700Another way to think about it (for the mathematically inclined) is that
427EV::periodic will try to run the callback in this mode at the next 701EV::periodic will try to run the callback in this mode at the next
428possible time where C<$time = $at (mod $interval)>, regardless of any time 702possible time where C<$time = $at (mod $interval)>, regardless of any time
… …
434time the periodic watcher gets scheduled, the reschedule callback 708time the periodic watcher gets scheduled, the reschedule callback
435($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
436time as second argument. 710time as second argument.
437 711
438I<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
439watcher, 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
440afterwards. 714you need to stop it, return 1e30 and stop it afterwards. You may create
715and start a C<EV::prepare> watcher for this task.
441 716
442It 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
443(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
444will usually be called just before the callback will be triggered, but 719argument). It will usually be called just before the callback will be
445might be called at other times, too. 720triggered, but might be called at other times, too.
446 721
447This 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
448triggers on each midnight, local time (actually 24 hours after the last 723triggers on each midnight, local time (actually one day after the last
449midnight, to keep the example simple. If you know a way to do it correctly 724midnight, to keep the example simple):
450in about the same space (without requiring elaborate modules), drop me a
451note :):
452 725
453 my $daily = EV::periodic 0, 0, sub { 726 my $daily = EV::periodic 0, 0, sub {
454 my ($w, $now) = @_; 727 my ($w, $now) = @_;
455 728
456 use Time::Local (); 729 use Time::Local ();
457 my (undef, undef, undef, $d, $m, $y) = localtime $now; 730 my (undef, undef, undef, $d, $m, $y) = localtime $now;
458 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y 731 Time::Local::timelocal_nocheck 0, 0, 0, $d + 1, $m, $y
459 }, sub { 732 }, sub {
460 print "it's midnight or likely shortly after, now\n"; 733 print "it's midnight or likely shortly after, now\n";
461 }; 734 };
462 735
463=back 736=back
… …
471 744
472=item $w->again 745=item $w->again
473 746
474Simply stops and starts the watcher again. 747Simply stops and starts the watcher again.
475 748
749=item $time = $w->at
750
751Return the time that the watcher is expected to trigger next.
752
476=back 753=back
477 754
478 755
479=head3 SIGNAL WATCHERS - signal me when a signal gets signalled! 756=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
480 757
481=over 4 758=over 4
482 759
483=item $w = EV::signal $signal, $callback 760=item $w = EV::signal $signal, $callback
484 761
485=item $w = EV::signal_ns $signal, $callback 762=item $w = EV::signal_ns $signal, $callback
763
764=item $w = $loop->signal ($signal, $callback)
765
766=item $w = $loop->signal_ns ($signal, $callback)
486 767
487Call 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
488number 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.
489 774
490EV 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
491component 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,
492and 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
493add/remove callbacks to C<%SIG>, so watch out. 778add/remove callbacks to C<%SIG>, so watch out.
… …
513 798
514=head3 CHILD WATCHERS - watch out for process status changes 799=head3 CHILD WATCHERS - watch out for process status changes
515 800
516=over 4 801=over 4
517 802
518=item $w = EV::child $pid, $callback 803=item $w = EV::child $pid, $trace, $callback
519 804
520=item $w = EV::child_ns $pid, $callback 805=item $w = EV::child_ns $pid, $trace, $callback
521 806
807=item $w = $loop->child ($pid, $trace, $callback)
808
809=item $w = $loop->child_ns ($pid, $trace, $callback)
810
522Call the callback when a status change for pid C<$pid> (or any pid if 811Call the callback when a status change for pid C<$pid> (or any pid
523C<$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
524a 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
525changed/zombie children and call the callback. 816changed/zombie children and call the callback.
526 817
527It 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
528has 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
… …
535You 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
536called. 827called.
537 828
538The 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.
539 830
540=item $w->set ($pid) 831=item $w->set ($pid, $trace)
541 832
542Reconfigures 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
543any time. 834any time.
544 835
545=item $current_pid = $w->pid 836=item $current_pid = $w->pid
546 837
547=item $old_pid = $w->pid ($new_pid)
548
549Returns the previously set process id and optionally set a new one. 838Returns the previously set process id and optionally set a new one.
550 839
551=item $exit_status = $w->rstatus 840=item $exit_status = $w->rstatus
552 841
553Return the exit/wait status (as returned by waitpid, see the waitpid entry 842Return the exit/wait status (as returned by waitpid, see the waitpid entry
… …
566=over 4 855=over 4
567 856
568=item $w = EV::stat $path, $interval, $callback 857=item $w = EV::stat $path, $interval, $callback
569 858
570=item $w = EV::stat_ns $path, $interval, $callback 859=item $w = EV::stat_ns $path, $interval, $callback
860
861=item $w = $loop->stat ($path, $interval, $callback)
862
863=item $w = $loop->stat_ns ($path, $interval, $callback)
571 864
572Call the callback when a file status change has been detected on 865Call the callback when a file status change has been detected on
573C<$path>. The C<$path> does not need to exist, changing from "path exists" 866C<$path>. The C<$path> does not need to exist, changing from "path exists"
574to "path does not exist" is a status change like any other. 867to "path does not exist" is a status change like any other.
575 868
… …
645=over 4 938=over 4
646 939
647=item $w = EV::idle $callback 940=item $w = EV::idle $callback
648 941
649=item $w = EV::idle_ns $callback 942=item $w = EV::idle_ns $callback
943
944=item $w = $loop->idle ($callback)
945
946=item $w = $loop->idle_ns ($callback)
650 947
651Call the callback when there are no other pending watchers of the same or 948Call the callback when there are no other pending watchers of the same or
652higher priority (excluding check, prepare and other idle watchers of the 949higher priority (excluding check, prepare and other idle watchers of the
653same or lower priority, of course). They are called idle watchers because 950same or lower priority, of course). They are called idle watchers because
654when the watcher is the highest priority pending event in the process, the 951when the watcher is the highest priority pending event in the process, the
… …
677 974
678=item $w = EV::prepare $callback 975=item $w = EV::prepare $callback
679 976
680=item $w = EV::prepare_ns $callback 977=item $w = EV::prepare_ns $callback
681 978
979=item $w = $loop->prepare ($callback)
980
981=item $w = $loop->prepare_ns ($callback)
982
682Call the callback just before the process would block. You can still 983Call the callback just before the process would block. You can still
683create/modify any watchers at this point. 984create/modify any watchers at this point.
684 985
685See the EV::check watcher, below, for explanations and an example. 986See the EV::check watcher, below, for explanations and an example.
686 987
… …
695 996
696=item $w = EV::check $callback 997=item $w = EV::check $callback
697 998
698=item $w = EV::check_ns $callback 999=item $w = EV::check_ns $callback
699 1000
1001=item $w = $loop->check ($callback)
1002
1003=item $w = $loop->check_ns ($callback)
1004
700Call 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
701gathered events), but before any other callbacks have been invoked. 1006gathered events), but before any other callbacks have been invoked.
702 1007
703This is used to integrate other event-based software into the EV 1008This can be used to integrate other event-based software into the EV
704mainloop: 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
705timer 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
706example of integrating Net::SNMP (with some details left out): 1011example of integrating Net::SNMP (with some details left out):
707 1012
708 our @snmp_watcher; 1013 our @snmp_watcher;
… …
738 # make the dispatcher handle any new stuff 1043 # make the dispatcher handle any new stuff
739 ... not shown 1044 ... not shown
740 }; 1045 };
741 1046
742The 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
743are destroyed before this cna happen (remember EV::check gets called 1048are destroyed before this can happen (remember EV::check gets called
744first). 1049first).
745 1050
746The 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.
747 1062
748=back 1063=back
749 1064
750 1065
751=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
… …
758 1073
759=item $w = EV::fork $callback 1074=item $w = EV::fork $callback
760 1075
761=item $w = EV::fork_ns $callback 1076=item $w = EV::fork_ns $callback
762 1077
1078=item $w = $loop->fork ($callback)
1079
1080=item $w = $loop->fork_ns ($callback)
1081
763Call the callback before the event loop is resumed in the child process 1082Call the callback before the event loop is resumed in the child process
764after a fork. 1083after a fork.
765 1084
766The C<fork_ns> variant doesn't start (activate) the newly created watcher. 1085The C<fork_ns> variant doesn't start (activate) the newly created watcher.
767 1086
768=back 1087=back
1088
1089
1090=head3 EMBED WATCHERS - when one backend isn't enough...
1091
1092This is a rather advanced watcher type that lets you embed one event loop
1093into another (currently only IO events are supported in the embedded
1094loop, other types of watchers might be handled in a delayed or incorrect
1095fashion and must not be used).
1096
1097See the libev documentation at
1098L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
1099(locally installed as F<EV::libev>) for more details.
1100
1101In short, this watcher is most useful on BSD systems without working
1102kqueue to still be able to handle a large number of sockets:
1103
1104 my $socket_loop;
1105
1106 # check wether we use SELECT or POLL _and_ KQUEUE is supported
1107 if (
1108 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
1109 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
1110 ) {
1111 # use kqueue for sockets
1112 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
1113 }
1114
1115 # use the default loop otherwise
1116 $socket_loop ||= EV::default_loop;
1117
1118=over 4
1119
1120=item $w = EV::embed $otherloop[, $callback]
1121
1122=item $w = EV::embed_ns $otherloop[, $callback]
1123
1124=item $w = $loop->embed ($otherloop[, $callback])
1125
1126=item $w = $loop->embed_ns ($otherloop[, $callback])
1127
1128Call the callback when the embedded event loop (C<$otherloop>) has any
1129I/O activity. The C<$callback> is optional: if it is missing, then the
1130embedded event loop will be managed automatically (which is recommended),
1131otherwise you have to invoke C<sweep> yourself.
1132
1133The C<embed_ns> variant doesn't start (activate) the newly created watcher.
1134
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.
769 1167
770 1168
771=head1 PERL SIGNALS 1169=head1 PERL SIGNALS
772 1170
773While 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
… …
782to be called on every event loop iteration by installing a C<EV::check> 1180to be called on every event loop iteration by installing a C<EV::check>
783watcher: 1181watcher:
784 1182
785 my $async_check = EV::check sub { }; 1183 my $async_check = EV::check sub { };
786 1184
787This ensures that perl shortly gets into control for a short time, and 1185This ensures that perl gets into control for a short time to handle any
788also ensures slower overall operation. 1186pending signals, and also ensures (slightly) slower overall operation.
789 1187
790=head1 THREADS 1188=head1 ITHREADS
791 1189
792Threads 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
793is 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
794on thread support for it. 1192supported (and enhanced support is available via L<Coro::EV>).
795 1193
796=head1 FORK 1194=head1 FORK
797 1195
798Most of the "improved" event delivering mechanisms of modern operating 1196Most of the "improved" event delivering mechanisms of modern operating
799systems 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
… …
815our $DIED = sub { 1213our $DIED = sub {
816 warn "EV: error in callback (ignoring): $@"; 1214 warn "EV: error in callback (ignoring): $@";
817}; 1215};
818 1216
819default_loop 1217default_loop
820 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; 1218 or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
821 1219
8221; 12201;
823 1221
824=head1 SEE ALSO 1222=head1 SEE ALSO
825 1223
1224L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS>
826L<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
827event loop), L<Coro::EV> (efficient coroutines with EV). 1226loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient thread
1227integration), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1228event-loop agnostic and portable event driven programming.
828 1229
829=head1 AUTHOR 1230=head1 AUTHOR
830 1231
831 Marc Lehmann <schmorp@schmorp.de> 1232 Marc Lehmann <schmorp@schmorp.de>
832 http://home.schmorp.de/ 1233 http://home.schmorp.de/
833 1234
834=cut 1235=cut
835 1236

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