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Revision 1.76 by root, Fri Dec 21 13:30:55 2007 UTC vs.
Revision 1.162 by root, Wed Jan 22 23:17:31 2020 UTC

… …
2 2
3EV - perl interface to libev, a high performance full-featured event loop 3EV - perl interface to libev, a high performance full-featured event loop
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use EV; 7 use EV;
8
9 # TIMERS
10
11 my $w = EV::timer 2, 0, sub {
12 warn "is called after 2s";
13 };
14
15 my $w = EV::timer 2, 2, sub {
16 warn "is called roughly every 2s (repeat = 2)";
17 };
18
19 undef $w; # destroy event watcher again
20
21 my $w = EV::periodic 0, 60, 0, sub {
22 warn "is called every minute, on the minute, exactly";
23 };
24
25 # IO
26
27 my $w = EV::io *STDIN, EV::READ, sub {
28 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29 warn "stdin is readable, you entered: ", <STDIN>;
30 };
31
32 # SIGNALS
33
34 my $w = EV::signal 'QUIT', sub {
35 warn "sigquit received\n";
36 };
37
38 # CHILD/PID STATUS CHANGES
8 39
9 # TIMERS 40 my $w = EV::child 666, 0, sub {
41 my ($w, $revents) = @_;
42 my $status = $w->rstatus;
43 };
10 44
11 my $w = EV::timer 2, 0, sub {
12 warn "is called after 2s";
13 };
14
15 my $w = EV::timer 2, 2, sub {
16 warn "is called roughly every 2s (repeat = 2)";
17 };
18
19 undef $w; # destroy event watcher again
20
21 my $w = EV::periodic 0, 60, 0, sub {
22 warn "is called every minute, on the minute, exactly";
23 };
24
25 # IO
26
27 my $w = EV::io *STDIN, EV::READ, sub {
28 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29 warn "stdin is readable, you entered: ", <STDIN>;
30 };
31
32 # SIGNALS
33
34 my $w = EV::signal 'QUIT', sub {
35 warn "sigquit received\n";
36 };
37
38 # CHILD/PID STATUS CHANGES
39
40 my $w = EV::child 666, sub {
41 my ($w, $revents) = @_;
42 my $status = $w->rstatus;
43 };
44
45 # STAT CHANGES 45 # STAT CHANGES
46 my $w = EV::stat "/etc/passwd", 10, sub { 46 my $w = EV::stat "/etc/passwd", 10, sub {
47 my ($w, $revents) = @_; 47 my ($w, $revents) = @_;
48 warn $w->path, " has changed somehow.\n"; 48 warn $w->path, " has changed somehow.\n";
49 }; 49 };
50 50
51 # MAINLOOP 51 # MAINLOOP
52 EV::loop; # loop until EV::unloop is called or all watchers stop 52 EV::run; # loop until EV::break is called or all watchers stop
53 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled 53 EV::run EV::RUN_ONCE; # block until at least one event could be handled
54 EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block 54 EV::run EV::RUN_NOWAIT; # try to handle same events, but do not block
55
56=head1 BEFORE YOU START USING THIS MODULE
57
58If you only need timer, I/O, signal, child and idle watchers and not the
59advanced functionality of this module, consider using L<AnyEvent> instead,
60specifically the simplified API described in L<AE>.
61
62When used with EV as backend, the L<AE> API is as fast as the native L<EV>
63API, but your programs/modules will still run with many other event loops.
55 64
56=head1 DESCRIPTION 65=head1 DESCRIPTION
57 66
58This module provides an interface to libev 67This module provides an interface to libev
59(L<http://software.schmorp.de/pkg/libev.html>). While the documentation 68(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
60below is comprehensive, one might also consult the documentation of libev 69below is comprehensive, one might also consult the documentation of
61itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on 70libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
62watcher semantics or some discussion on the available backends, or how to 71F<perldoc EV::libev>) for more subtle details on watcher semantics or some
63force a specific backend with C<LIBEV_FLAGS>, or just about in any case 72discussion on the available backends, or how to force a specific backend
64because it has much more detailed information. 73with C<LIBEV_FLAGS>, or just about in any case because it has much more
74detailed information.
75
76This module is very fast and scalable. It is actually so fast that you
77can use it through the L<AnyEvent> module, stay portable to other event
78loops (if you don't rely on any watcher types not available through it)
79and still be faster than with any other event loop currently supported in
80Perl.
81
82=head2 PORTING FROM EV 3.X to 4.X
83
84EV version 4 introduces a number of incompatible changes summarised
85here. According to the depreciation strategy used by libev, there is a
86compatibility layer in place so programs should continue to run unchanged
87(the XS interface lacks this layer, so programs using that one need to be
88updated).
89
90This compatibility layer will be switched off in some future release.
91
92All changes relevant to Perl are renames of symbols, functions and
93methods:
94
95 EV::loop => EV::run
96 EV::LOOP_NONBLOCK => EV::RUN_NOWAIT
97 EV::LOOP_ONESHOT => EV::RUN_ONCE
98
99 EV::unloop => EV::break
100 EV::UNLOOP_CANCEL => EV::BREAK_CANCEL
101 EV::UNLOOP_ONE => EV::BREAK_ONE
102 EV::UNLOOP_ALL => EV::BREAK_ALL
103
104 EV::TIMEOUT => EV::TIMER
105
106 EV::loop_count => EV::iteration
107 EV::loop_depth => EV::depth
108 EV::loop_verify => EV::verify
109
110The loop object methods corresponding to the functions above have been
111similarly renamed.
112
113=head2 MODULE EXPORTS
114
115This module does not export any symbols.
65 116
66=cut 117=cut
67 118
68package EV; 119package EV;
69 120
70use strict; 121use common::sense;
71 122
72BEGIN { 123BEGIN {
73 our $VERSION = '2.0'; 124 our $VERSION = '4.31';
74 use XSLoader; 125 use XSLoader;
126 local $^W = 0; # avoid spurious warning
75 XSLoader::load "EV", $VERSION; 127 XSLoader::load "EV", $VERSION;
76} 128}
77 129
78@EV::IO::ISA = 130@EV::IO::ISA =
79@EV::Timer::ISA = 131@EV::Timer::ISA =
… …
84@EV::Idle::ISA = 136@EV::Idle::ISA =
85@EV::Prepare::ISA = 137@EV::Prepare::ISA =
86@EV::Check::ISA = 138@EV::Check::ISA =
87@EV::Embed::ISA = 139@EV::Embed::ISA =
88@EV::Fork::ISA = 140@EV::Fork::ISA =
141@EV::Async::ISA =
89 "EV::Watcher"; 142 "EV::Watcher";
90 143
91@EV::Loop::Default::ISA = "EV::Loop"; 144@EV::Loop::Default::ISA = "EV::Loop";
92 145
93=head1 EVENT LOOPS 146=head1 EVENT LOOPS
… …
102selecting a working backend (which for example rules out kqueue on most 155selecting a working backend (which for example rules out kqueue on most
103BSDs). Modules should, unless they have "special needs" always use the 156BSDs). Modules should, unless they have "special needs" always use the
104default loop as this is fastest (perl-wise), best supported by other 157default loop as this is fastest (perl-wise), best supported by other
105modules (e.g. AnyEvent or Coro) and most portable event loop. 158modules (e.g. AnyEvent or Coro) and most portable event loop.
106 159
107For specific programs you cna create additional event loops dynamically. 160For specific programs you can create additional event loops dynamically.
108 161
109=over 4 162If you want to take advantage of kqueue (which often works properly for
163sockets only) even though the default loop doesn't enable it, you can
164I<embed> a kqueue loop into the default loop: running the default loop
165will then also service the kqueue loop to some extent. See the example in
166the section about embed watchers for an example on how to achieve that.
110 167
168=over 4
169
111=item $loop = new EV::loop [$flags] 170=item $loop = new EV::Loop [$flags]
112 171
113Create a new event loop as per the specified flags. Please refer to the 172Create a new event loop as per the specified flags. Please refer to
114C<ev_loop_new ()> function description in the libev documentation 173the C<ev_loop_new ()> function description in the libev documentation
115(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>) 174(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
116for more info. 175or locally-installed as F<EV::libev> manpage) for more info.
117 176
118The loop will automatically be destroyed when it is no longer referenced 177The loop will automatically be destroyed when it is no longer referenced
119by any watcher and the loop object goes out of scope. 178by any watcher and the loop object goes out of scope.
120 179
121Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop 180If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
122is protected by this module. 181is recommended, as only the default event loop is protected by this
182module. If you I<are> embedding this loop in the default loop, this is not
183necessary, as C<EV::embed> automatically does the right thing on fork.
123 184
124=item $loop->loop_fork 185=item $loop->loop_fork
125 186
126Must be called after a fork in the child, before entering or continuing 187Must be called after a fork in the child, before entering or continuing
127the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls 188the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
128this fucntion automatically, at some performance loss (refer to the libev 189this function automatically, at some performance loss (refer to the libev
129documentation). 190documentation).
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.
130 205
131=back 206=back
132 207
133 208
134=head1 BASIC INTERFACE 209=head1 BASIC INTERFACE
… …
141throws an exception (with $@ containing the error). The default prints an 216throws an exception (with $@ containing the error). The default prints an
142informative message and continues. 217informative message and continues.
143 218
144If this callback throws an exception it will be silently ignored. 219If this callback throws an exception it will be silently ignored.
145 220
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
146=item $time = EV::time 235=item $time = EV::time
147 236
148Returns the current time in (fractional) seconds since the epoch. 237Returns the current time in (fractional) seconds since the epoch.
149 238
150=item $time = EV::now 239=item $time = EV::now
151 240
152=item $time = $loop->now 241=item $time = $loop->now
153 242
154Returns the time the last event loop iteration has been started. This 243Returns the time the last event loop iteration has been started. This
155is 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
156usually faster then calling EV::time. 245usually faster then calling EV::time.
157 246
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
158=item $backend = EV::backend 289=item $backend = EV::backend
159 290
160=item $backend = $loop->backend 291=item $backend = $loop->backend
161 292
162Returns an integer describing the backend used by libev (EV::METHOD_SELECT 293Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
163or EV::METHOD_EPOLL). 294or EV::BACKEND_EPOLL).
164 295
165=item EV::loop [$flags] 296=item $active = EV::run [$flags]
166 297
167=item $loop->loop ([$flags]) 298=item $active = $loop->run ([$flags])
168 299
169Begin checking for events and calling callbacks. It returns when a 300Begin checking for events and calling callbacks. It returns when a
170callback 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".
171 306
172The $flags argument can be one of the following: 307The $flags argument can be one of the following:
173 308
174 0 as above 309 0 as above
175 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 310 EV::RUN_ONCE block at most once (wait, but do not loop)
176 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 311 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
177 312
178=item EV::unloop [$how] 313=item EV::break [$how]
179 314
180=item $loop->unloop ([$how]) 315=item $loop->break ([$how])
181 316
182When 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
183innermost call to EV::loop return. 318innermost call to EV::run return.
184 319
185When 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
186fast as possible. 321return as fast as possible.
187 322
188=item $count = EV::loop_count 323When called with an argument of EV::BREAK_CANCEL, any pending break will
324be cancelled.
189 325
326=item $count = EV::iteration
327
190=item $count = $loop->loop_count 328=item $count = $loop->iteration
191 329
192Return the number of times the event loop has polled for new 330Return the number of times the event loop has polled for new
193events. Sometiems useful as a generation counter. 331events. Sometimes useful as a generation counter.
194 332
195=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 333=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
196 334
197=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 335=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
198 336
… …
204| 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
205you 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
206C<$fh_or_undef> and C<0> for C<$events>). 344C<$fh_or_undef> and C<0> for C<$events>).
207 345
208If timeout is C<undef> or negative, then there will be no 346If timeout is C<undef> or negative, then there will be no
209timeout. Otherwise a EV::timer with this value will be started. 347timeout. Otherwise an C<EV::timer> with this value will be started.
210 348
211When 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
212the callback will be called with the received event set (in general 350the callback will be called with the received event set (in general
213you 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>,
214C<EV::WRITE> and C<EV::TIMEOUT>). 352C<EV::WRITE> and C<EV::TIMER>).
215 353
216EV::once doesn't return anything: the watchers stay active till either 354EV::once doesn't return anything: the watchers stay active till either
217of 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
218invoked. 356invoked.
219 357
220=item EV::feed_fd_event ($fd, $revents) 358=item EV::feed_fd_event $fd, $revents
221 359
222=item $loop->feed_fd_event ($fd, $revents) 360=item $loop->feed_fd_event ($fd, $revents)
223 361
224Feed an event on a file descriptor into EV. EV will react to this call as 362Feed an event on a file descriptor into EV. EV will react to this call as
225if the readyness notifications specified by C<$revents> (a combination of 363if the readyness notifications specified by C<$revents> (a combination of
226C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. 364C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
227 365
228=item EV::feed_signal_event ($signal) 366=item EV::feed_signal_event $signal
229 367
230Feed a signal event into EV. EV will react to this call as if the signal 368Feed a signal event into the default loop. EV will react to this call as
231specified by C<$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.
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.
232 401
233=back 402=back
234 403
235 404
236=head1 WATCHER OBJECTS 405=head1 WATCHER OBJECTS
237 406
238A 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
239event. 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
240would create an EV::io watcher for that: 409would create an EV::io watcher for that:
241 410
242 my $watcher = EV::io *STDIN, EV::READ, sub { 411 my $watcher = EV::io *STDIN, EV::READ, sub {
243 my ($watcher, $revents) = @_; 412 my ($watcher, $revents) = @_;
244 warn "yeah, STDIN should not be readable without blocking!\n" 413 warn "yeah, STDIN should now be readable without blocking!\n"
245 }; 414 };
246 415
247All watchers can be active (waiting for events) or inactive (paused). Only 416All watchers can be active (waiting for events) or inactive (paused). Only
248active watchers will have their callbacks invoked. All callbacks will be 417active watchers will have their callbacks invoked. All callbacks will be
249called 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
250events. 419events.
251 420
252Each 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
253same callback for multiple watchers. The event mask is named after the 422same callback for multiple watchers. The event mask is named after the
254type, 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,
255EV::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
256(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).
257uses EV::TIMEOUT).
258 426
259In 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
260the 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
261its 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.
262 430
… …
333Feed some events on this watcher into EV. EV will react to this call as if 501Feed some events on this watcher into EV. EV will react to this call as if
334the watcher had received the given C<$revents> mask. 502the watcher had received the given C<$revents> mask.
335 503
336=item $revents = $w->clear_pending 504=item $revents = $w->clear_pending
337 505
338If the watcher is pending, this function returns clears its pending status 506If the watcher is pending, this function clears its pending status and
339and returns its C<$revents> bitset (as if its callback was invoked). If the 507returns its C<$revents> bitset (as if its callback was invoked). If the
340watcher isn't pending it does nothing and returns C<0>. 508watcher isn't pending it does nothing and returns C<0>.
341 509
342=item $previous_state = $w->keepalive ($bool) 510=item $previous_state = $w->keepalive ($bool)
343 511
344Normally, C<EV::loop> will return when there are no active watchers 512Normally, C<EV::run> will return when there are no active watchers
345(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
346convinient because it allows you to start your watchers (and your jobs), 514convenient because it allows you to start your watchers (and your jobs),
347call 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
348finished (or they forgot to register some watchers for their task :). 516finished (or they forgot to register some watchers for their task :).
349 517
350Sometimes, however, this gets in your way, for example when you the module 518Sometimes, however, this gets in your way, for example when the module
351that 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
352as 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
353somebody else even). Then you might want any outstanding requests to be 521somebody else even). Then you might want any outstanding requests to be
354handled, 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
355because you happen to have this long-running UDP port watcher. 523because you happen to have this long-running UDP port watcher.
356 524
357In 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
358though 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.
359 527
360The 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
361any time. 529any time.
362 530
363Example: 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
364event loop from running just because of that watcher. 532event loop from running just because of that watcher.
365 533
366 my $udp_socket = ... 534 my $udp_socket = ...
367 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 535 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
368 $1000udp_watcher->keepalive (0); 536 $udp_watcher->keepalive (0);
369 537
370=item $loop = $w->loop 538=item $loop = $w->loop
371 539
372Return the loop that this watcher is attached to. 540Return the loop that this watcher is attached to.
373 541
… …
430 598
431=item $w = $loop->timer ($after, $repeat, $callback) 599=item $w = $loop->timer ($after, $repeat, $callback)
432 600
433=item $w = $loop->timer_ns ($after, $repeat, $callback) 601=item $w = $loop->timer_ns ($after, $repeat, $callback)
434 602
435Calls the callback after C<$after> seconds (which may be fractional). If 603Calls the callback after C<$after> seconds (which may be fractional or
436C<$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
437value as $after) after the callback returns. 605the $repeat value as $after) after the callback returns.
438 606
439This means that the callback would be called roughly after C<$after> 607This means that the callback would be called roughly after C<$after>
440seconds, and then every C<$repeat> seconds. The timer does his best not 608seconds, and then every C<$repeat> seconds. The timer does his best not
441to 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
442loop 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,
… …
446in 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
447clock, the timer will nevertheless run (roughly) the same time. 615clock, the timer will nevertheless run (roughly) the same time.
448 616
449The 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.
450 618
451=item $w->set ($after, $repeat) 619=item $w->set ($after, $repeat = 0)
452 620
453Reconfigures 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
454any time. 622any time.
455 623
456=item $w->again 624=item $w->again
625
626=item $w->again ($repeat)
457 627
458Similar 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:
459 629
460If the timer is active and non-repeating, it will be stopped. 630If the timer is active and non-repeating, it will be stopped.
461 631
… …
468 638
469This behaviour is useful when you have a timeout for some IO 639This behaviour is useful when you have a timeout for some IO
470operation. 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
471C<$repeat>, and then, in the read/write watcher, run the C<again> method 641C<$repeat>, and then, in the read/write watcher, run the C<again> method
472on 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 $old_repeat = $w->reapat ([$new_repeat])
652
653Returns the current value of the repeat attribute and optionally sets a
654new one. Setting the new one will not restart the watcher - if the watcher
655is active, the new repeat value is used whenever it expires next.
473 656
474=back 657=back
475 658
476 659
477=head3 PERIODIC WATCHERS - to cron or not to cron? 660=head3 PERIODIC WATCHERS - to cron or not to cron?
… …
502This time simply fires at the wallclock time C<$at> and doesn't repeat. It 685This time simply fires at the wallclock time C<$at> and doesn't repeat. It
503will not adjust when a time jump occurs, that is, if it is to be run 686will not adjust when a time jump occurs, that is, if it is to be run
504at January 1st 2011 then it will run when the system time reaches or 687at January 1st 2011 then it will run when the system time reaches or
505surpasses this time. 688surpasses this time.
506 689
507=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 690=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
508 691
509In this mode the watcher will always be scheduled to time out at the 692In this mode the watcher will always be scheduled to time out at the
510next C<$at + N * $interval> time (for some integer N) and then repeat, 693next C<$at + N * $interval> time (for the lowest integer N) and then repeat,
511regardless of any time jumps. 694regardless of any time jumps. Note that, since C<N> can be negative, the
695first trigger can happen before C<$at>.
512 696
513This can be used to create timers that do not drift with respect to system 697This can be used to create timers that do not drift with respect to system
514time: 698time:
515 699
516 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; 700 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
517 701
518That doesn't mean there will always be 3600 seconds in between triggers, 702That doesn't mean there will always be 3600 seconds in between triggers,
519but only that the the clalback will be called when the system time shows a 703but only that the the callback will be called when the system time shows a
520full hour (UTC). 704full hour (UTC).
521 705
522Another way to think about it (for the mathematically inclined) is that 706Another way to think about it (for the mathematically inclined) is that
523EV::periodic will try to run the callback in this mode at the next 707EV::periodic will try to run the callback in this mode at the next
524possible time where C<$time = $at (mod $interval)>, regardless of any time 708possible time where C<$time = $at (mod $interval)>, regardless of any time
… …
530time the periodic watcher gets scheduled, the reschedule callback 714time the periodic watcher gets scheduled, the reschedule callback
531($reschedule_cb) will be called with the watcher as first, and the current 715($reschedule_cb) will be called with the watcher as first, and the current
532time as second argument. 716time as second argument.
533 717
534I<This callback MUST NOT stop or destroy this or any other periodic 718I<This callback MUST NOT stop or destroy this or any other periodic
535watcher, ever>. If you need to stop it, return 1e30 and stop it 719watcher, ever, and MUST NOT call any event loop functions or methods>. If
536afterwards. 720you need to stop it, return 1e30 and stop it afterwards. You may create
721and start an C<EV::prepare> watcher for this task.
537 722
538It must return the next time to trigger, based on the passed time value 723It must return the next time to trigger, based on the passed time value
539(that is, the lowest time value larger than to the second argument). It 724(that is, the lowest time value larger than or equal to to the second
540will usually be called just before the callback will be triggered, but 725argument). It will usually be called just before the callback will be
541might be called at other times, too. 726triggered, but might be called at other times, too.
542 727
543This can be used to create very complex timers, such as a timer that 728This can be used to create very complex timers, such as a timer that
544triggers on each midnight, local time (actually 24 hours after the last 729triggers on each midnight, local time (actually one day after the last
545midnight, to keep the example simple. If you know a way to do it correctly 730midnight, to keep the example simple):
546in about the same space (without requiring elaborate modules), drop me a
547note :):
548 731
549 my $daily = EV::periodic 0, 0, sub { 732 my $daily = EV::periodic 0, 0, sub {
550 my ($w, $now) = @_; 733 my ($w, $now) = @_;
551 734
552 use Time::Local (); 735 use Time::Local ();
553 my (undef, undef, undef, $d, $m, $y) = localtime $now; 736 my (undef, undef, undef, $d, $m, $y) = localtime $now;
554 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y 737 Time::Local::timelocal_nocheck 0, 0, 0, $d + 1, $m, $y
555 }, sub { 738 }, sub {
556 print "it's midnight or likely shortly after, now\n"; 739 print "it's midnight or likely shortly after, now\n";
557 }; 740 };
558 741
559=back 742=back
… …
571 754
572=item $time = $w->at 755=item $time = $w->at
573 756
574Return the time that the watcher is expected to trigger next. 757Return the time that the watcher is expected to trigger next.
575 758
759=item $old_offset = $w->offset ([$new_offset])
760
761Returns the current value of the offset attribute and optionally sets a
762new one. Setting the new one will not restart the watcher - if the watcher
763is active, the new offset value is used whenever it expires next.
764
765=item $old_interval = $w->interval ([$new_interval])
766
767See above, for the interval attribute.
768
769=item $old_reschedule_cb = $w->reschedule_cb ([$new_reschedule_xcb])
770
771See above, for the reschedule callback.
772
576=back 773=back
577 774
578 775
579=head3 SIGNAL WATCHERS - signal me when a signal gets signalled! 776=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
580 777
581=over 4 778=over 4
582 779
583=item $w = EV::signal $signal, $callback 780=item $w = EV::signal $signal, $callback
584 781
585=item $w = EV::signal_ns $signal, $callback 782=item $w = EV::signal_ns $signal, $callback
783
784=item $w = $loop->signal ($signal, $callback)
785
786=item $w = $loop->signal_ns ($signal, $callback)
586 787
587Call the callback when $signal is received (the signal can be specified by 788Call the callback when $signal is received (the signal can be specified by
588number or by name, just as with C<kill> or C<%SIG>). 789number or by name, just as with C<kill> or C<%SIG>).
790
791Only one event loop can grab a given signal - attempting to grab the same
792signal from two EV loops will crash the program immediately or cause data
793corruption.
589 794
590EV will grab the signal for the process (the kernel only allows one 795EV will grab the signal for the process (the kernel only allows one
591component to receive a signal at a time) when you start a signal watcher, 796component to receive a signal at a time) when you start a signal watcher,
592and removes it again when you stop it. Perl does the same when you 797and removes it again when you stop it. Perl does the same when you
593add/remove callbacks to C<%SIG>, so watch out. 798add/remove callbacks to C<%SIG>, so watch out.
… …
613 818
614=head3 CHILD WATCHERS - watch out for process status changes 819=head3 CHILD WATCHERS - watch out for process status changes
615 820
616=over 4 821=over 4
617 822
618=item $w = EV::child $pid, $callback 823=item $w = EV::child $pid, $trace, $callback
619 824
620=item $w = EV::child_ns $pid, $callback 825=item $w = EV::child_ns $pid, $trace, $callback
621 826
622=item $w = $loop->child ($pid, $callback) 827=item $w = $loop->child ($pid, $trace, $callback)
623 828
624=item $w = $loop->child_ns ($pid, $callback) 829=item $w = $loop->child_ns ($pid, $trace, $callback)
625 830
626Call the callback when a status change for pid C<$pid> (or any pid if 831Call the callback when a status change for pid C<$pid> (or any pid
627C<$pid> is 0) has been received. More precisely: when the process receives 832if C<$pid> is 0) has been received (a status change happens when the
833process terminates or is killed, or, when trace is true, additionally when
834it is stopped or continued). More precisely: when the process receives
628a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all 835a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
629changed/zombie children and call the callback. 836changed/zombie children and call the callback.
630 837
631It is valid (and fully supported) to install a child watcher after a child 838It is valid (and fully supported) to install a child watcher after a child
632has exited but before the event loop has started its next iteration (for 839has exited but before the event loop has started its next iteration (for
… …
639You can have as many pid watchers per pid as you want, they will all be 846You can have as many pid watchers per pid as you want, they will all be
640called. 847called.
641 848
642The C<child_ns> variant doesn't start (activate) the newly created watcher. 849The C<child_ns> variant doesn't start (activate) the newly created watcher.
643 850
644=item $w->set ($pid) 851=item $w->set ($pid, $trace)
645 852
646Reconfigures the watcher, see the constructor above for details. Can be called at 853Reconfigures the watcher, see the constructor above for details. Can be called at
647any time. 854any time.
648 855
649=item $current_pid = $w->pid 856=item $current_pid = $w->pid
650
651=item $old_pid = $w->pid ($new_pid)
652 857
653Returns the previously set process id and optionally set a new one. 858Returns the previously set process id and optionally set a new one.
654 859
655=item $exit_status = $w->rstatus 860=item $exit_status = $w->rstatus
656 861
… …
818=item $w = $loop->check_ns ($callback) 1023=item $w = $loop->check_ns ($callback)
819 1024
820Call the callback just after the process wakes up again (after it has 1025Call the callback just after the process wakes up again (after it has
821gathered events), but before any other callbacks have been invoked. 1026gathered events), but before any other callbacks have been invoked.
822 1027
823This is used to integrate other event-based software into the EV 1028This can be used to integrate other event-based software into the EV
824mainloop: You register a prepare callback and in there, you create io and 1029mainloop: You register a prepare callback and in there, you create io and
825timer watchers as required by the other software. Here is a real-world 1030timer watchers as required by the other software. Here is a real-world
826example of integrating Net::SNMP (with some details left out): 1031example of integrating Net::SNMP (with some details left out):
827 1032
828 our @snmp_watcher; 1033 our @snmp_watcher;
… …
858 # make the dispatcher handle any new stuff 1063 # make the dispatcher handle any new stuff
859 ... not shown 1064 ... not shown
860 }; 1065 };
861 1066
862The callbacks of the created watchers will not be called as the watchers 1067The callbacks of the created watchers will not be called as the watchers
863are destroyed before this cna happen (remember EV::check gets called 1068are destroyed before this can happen (remember EV::check gets called
864first). 1069first).
865 1070
866The C<check_ns> variant doesn't start (activate) the newly created watcher. 1071The C<check_ns> variant doesn't start (activate) the newly created watcher.
1072
1073=item EV::CHECK constant issues
1074
1075Like all other watcher types, there is a bitmask constant for use in
1076C<$revents> and other places. The C<EV::CHECK> is special as it has
1077the same name as the C<CHECK> sub called by Perl. This doesn't cause
1078big issues on newer perls (beginning with 5.8.9), but it means thatthe
1079constant must be I<inlined>, i.e. runtime calls will not work. That means
1080that as long as you always C<use EV> and then C<EV::CHECK> you are on the
1081safe side.
867 1082
868=back 1083=back
869 1084
870 1085
871=head3 FORK WATCHERS - the audacity to resume the event loop after a fork 1086=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
… …
888after a fork. 1103after a fork.
889 1104
890The C<fork_ns> variant doesn't start (activate) the newly created watcher. 1105The C<fork_ns> variant doesn't start (activate) the newly created watcher.
891 1106
892=back 1107=back
1108
1109
1110=head3 EMBED WATCHERS - when one backend isn't enough...
1111
1112This is a rather advanced watcher type that lets you embed one event loop
1113into another (currently only IO events are supported in the embedded
1114loop, other types of watchers might be handled in a delayed or incorrect
1115fashion and must not be used).
1116
1117See the libev documentation at
1118L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
1119(locally installed as F<EV::libev>) for more details.
1120
1121In short, this watcher is most useful on BSD systems without working
1122kqueue to still be able to handle a large number of sockets:
1123
1124 my $socket_loop;
1125
1126 # check wether we use SELECT or POLL _and_ KQUEUE is supported
1127 if (
1128 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
1129 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
1130 ) {
1131 # use kqueue for sockets
1132 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
1133 }
1134
1135 # use the default loop otherwise
1136 $socket_loop ||= EV::default_loop;
1137
1138=over 4
1139
1140=item $w = EV::embed $otherloop[, $callback]
1141
1142=item $w = EV::embed_ns $otherloop[, $callback]
1143
1144=item $w = $loop->embed ($otherloop[, $callback])
1145
1146=item $w = $loop->embed_ns ($otherloop[, $callback])
1147
1148Call the callback when the embedded event loop (C<$otherloop>) has any
1149I/O activity. The C<$callback> is optional: if it is missing, then the
1150embedded event loop will be managed automatically (which is recommended),
1151otherwise you have to invoke C<sweep> yourself.
1152
1153The C<embed_ns> variant doesn't start (activate) the newly created watcher.
1154
1155=back
1156
1157=head3 ASYNC WATCHERS - how to wake up another event loop
1158
1159Async watchers are provided by EV, but have little use in perl directly,
1160as perl neither supports threads running in parallel nor direct access to
1161signal handlers or other contexts where they could be of value.
1162
1163It is, however, possible to use them from the XS level.
1164
1165Please see the libev documentation for further details.
1166
1167=over 4
1168
1169=item $w = EV::async $callback
1170
1171=item $w = EV::async_ns $callback
1172
1173=item $w = $loop->async ($callback)
1174
1175=item $w = $loop->async_ns ($callback)
1176
1177=item $w->send
1178
1179=item $bool = $w->async_pending
1180
1181=back
1182
1183=head3 CLEANUP WATCHERS - how to clean up when the event loop goes away
1184
1185Cleanup watchers are not supported on the Perl level, they can only be
1186used via XS currently.
893 1187
894 1188
895=head1 PERL SIGNALS 1189=head1 PERL SIGNALS
896 1190
897While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour 1191While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
… …
909 my $async_check = EV::check sub { }; 1203 my $async_check = EV::check sub { };
910 1204
911This ensures that perl gets into control for a short time to handle any 1205This ensures that perl gets into control for a short time to handle any
912pending signals, and also ensures (slightly) slower overall operation. 1206pending signals, and also ensures (slightly) slower overall operation.
913 1207
914=head1 THREADS 1208=head1 ITHREADS
915 1209
916Threads are not supported by this module in any way. Perl pseudo-threads 1210Ithreads are not supported by this module in any way. Perl pseudo-threads
917is evil stuff and must die. As soon as Perl gains real threads I will work 1211is evil stuff and must die. Real threads as provided by Coro are fully
918on thread support for it. 1212supported (and enhanced support is available via L<Coro::EV>).
919 1213
920=head1 FORK 1214=head1 FORK
921 1215
922Most of the "improved" event delivering mechanisms of modern operating 1216Most of the "improved" event delivering mechanisms of modern operating
923systems have quite a few problems with fork(2) (to put it bluntly: it is 1217systems have quite a few problems with fork(2) (to put it bluntly: it is
… …
945 1239
9461; 12401;
947 1241
948=head1 SEE ALSO 1242=head1 SEE ALSO
949 1243
1244L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS>
950L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as 1245(asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as event
951event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient 1246loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient thread
952coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP). 1247integration), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1248event-loop agnostic and portable event driven programming.
953 1249
954=head1 AUTHOR 1250=head1 AUTHOR
955 1251
956 Marc Lehmann <schmorp@schmorp.de> 1252 Marc Lehmann <schmorp@schmorp.de>
957 http://home.schmorp.de/ 1253 http://home.schmorp.de/
958 1254
959=cut 1255=cut
960 1256

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