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Revision 1.72 by root, Thu Dec 20 07:12:57 2007 UTC vs.
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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::unloop 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 = '4.15';
74 use XSLoader; 125 use XSLoader;
75 XSLoader::load "EV", $VERSION; 126 XSLoader::load "EV", $VERSION;
76} 127}
77 128
78@EV::IO::ISA = 129@EV::IO::ISA =
… …
84@EV::Idle::ISA = 135@EV::Idle::ISA =
85@EV::Prepare::ISA = 136@EV::Prepare::ISA =
86@EV::Check::ISA = 137@EV::Check::ISA =
87@EV::Embed::ISA = 138@EV::Embed::ISA =
88@EV::Fork::ISA = 139@EV::Fork::ISA =
140@EV::Async::ISA =
89 "EV::Watcher"; 141 "EV::Watcher";
90 142
91@EV::Loop::Default::ISA = "EV::Loop"; 143@EV::Loop::Default::ISA = "EV::Loop";
144
145=head1 EVENT LOOPS
146
147EV supports multiple event loops: There is a single "default event loop"
148that can handle everything including signals and child watchers, and any
149number of "dynamic event loops" that can use different backends (with
150various limitations), but no child and signal watchers.
151
152You do not have to do anything to create the default event loop: When
153the module is loaded a suitable backend is selected on the premise of
154selecting a working backend (which for example rules out kqueue on most
155BSDs). Modules should, unless they have "special needs" always use the
156default loop as this is fastest (perl-wise), best supported by other
157modules (e.g. AnyEvent or Coro) and most portable event loop.
158
159For specific programs you can create additional event loops dynamically.
160
161If you want to take advantage of kqueue (which often works properly for
162sockets only) even though the default loop doesn't enable it, you can
163I<embed> a kqueue loop into the default loop: running the default loop
164will then also service the kqueue loop to some extent. See the example in
165the section about embed watchers for an example on how to achieve that.
166
167=over 4
168
169=item $loop = new EV::Loop [$flags]
170
171Create a new event loop as per the specified flags. Please refer to
172the C<ev_loop_new ()> function description in the libev documentation
173(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
174or locally-installed as F<EV::libev> manpage) for more info.
175
176The loop will automatically be destroyed when it is no longer referenced
177by any watcher and the loop object goes out of scope.
178
179If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
180is recommended, as only the default event loop is protected by this
181module. If you I<are> embedding this loop in the default loop, this is not
182necessary, as C<EV::embed> automatically does the right thing on fork.
183
184=item $loop->loop_fork
185
186Must be called after a fork in the child, before entering or continuing
187the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
188this function automatically, at some performance loss (refer to the libev
189documentation).
190
191=item $loop->verify
192
193Calls C<ev_verify> to make internal consistency checks (for debugging
194libev) and abort the program if any data structures were found to be
195corrupted.
196
197=item $loop = EV::default_loop [$flags]
198
199Return the default loop (which is a singleton object). Since this module
200already creates the default loop with default flags, specifying flags here
201will not have any effect unless you destroy the default loop first, which
202isn't supported. So in short: don't do it, and if you break it, you get to
203keep the pieces.
204
205=back
206
92 207
93=head1 BASIC INTERFACE 208=head1 BASIC INTERFACE
94 209
95=over 4 210=over 4
96 211
… …
100throws an exception (with $@ containing the error). The default prints an 215throws an exception (with $@ containing the error). The default prints an
101informative message and continues. 216informative message and continues.
102 217
103If this callback throws an exception it will be silently ignored. 218If this callback throws an exception it will be silently ignored.
104 219
220=item $flags = EV::supported_backends
221
222=item $flags = EV::recommended_backends
223
224=item $flags = EV::embeddable_backends
225
226Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
227instance of EV, the set of recommended backends (supposed to be good) for
228this platform and the set of embeddable backends (see EMBED WATCHERS).
229
230=item EV::sleep $seconds
231
232Block the process for the given number of (fractional) seconds.
233
105=item $time = EV::time 234=item $time = EV::time
106 235
107Returns the current time in (fractional) seconds since the epoch. 236Returns the current time in (fractional) seconds since the epoch.
108 237
109=item $time = EV::now 238=item $time = EV::now
110 239
240=item $time = $loop->now
241
111Returns the time the last event loop iteration has been started. This 242Returns the time the last event loop iteration has been started. This
112is the time that (relative) timers are based on, and refering to it is 243is the time that (relative) timers are based on, and referring to it is
113usually faster then calling EV::time. 244usually faster then calling EV::time.
114 245
115=item $method = EV::method 246=item EV::now_update
116 247
248=item $loop->now_update
249
250Establishes the current time by querying the kernel, updating the time
251returned by C<EV::now> in the progress. This is a costly operation and
252is usually done automatically within C<EV::loop>.
253
254This function is rarely useful, but when some event callback runs for a
255very long time without entering the event loop, updating libev's idea of
256the current time is a good idea.
257
258=item EV::suspend
259
260=item $loop->suspend
261
262=item EV::resume
263
264=item $loop->resume
265
266These two functions suspend and resume a loop, for use when the loop is
267not used for a while and timeouts should not be processed.
268
269A typical use case would be an interactive program such as a game: When
270the user presses C<^Z> to suspend the game and resumes it an hour later it
271would be best to handle timeouts as if no time had actually passed while
272the program was suspended. This can be achieved by calling C<suspend>
273in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
274C<resume> directly afterwards to resume timer processing.
275
276Effectively, all C<timer> watchers will be delayed by the time spend
277between C<suspend> and C<resume>, and all C<periodic> watchers
278will be rescheduled (that is, they will lose any events that would have
279occured while suspended).
280
281After calling C<suspend> you B<must not> call I<any> function on the given
282loop other than C<resume>, and you B<must not> call C<resume>
283without a previous call to C<suspend>.
284
285Calling C<suspend>/C<resume> has the side effect of updating the event
286loop time (see C<now_update>).
287
288=item $backend = EV::backend
289
290=item $backend = $loop->backend
291
117Returns an integer describing the backend used by libev (EV::METHOD_SELECT 292Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
118or EV::METHOD_EPOLL). 293or EV::BACKEND_EPOLL).
119 294
120=item EV::loop [$flags] 295=item $active = EV::run [$flags]
296
297=item $active = $loop->run ([$flags])
121 298
122Begin checking for events and calling callbacks. It returns when a 299Begin checking for events and calling callbacks. It returns when a
123callback calls EV::unloop. 300callback calls EV::unloop or the flasg are nonzero (in which case the
301return value is true) or when there are no active watchers which reference
302the loop (keepalive is true), in which case the return value will be
303false. The returnv alue can generally be interpreted as "if true, there is
304more work left to do".
124 305
125The $flags argument can be one of the following: 306The $flags argument can be one of the following:
126 307
127 0 as above 308 0 as above
128 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 309 EV::RUN_ONCE block at most once (wait, but do not loop)
129 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 310 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
130 311
131=item EV::unloop [$how] 312=item EV::break [$how]
132 313
314=item $loop->break ([$how])
315
133When called with no arguments or an argument of EV::UNLOOP_ONE, makes the 316When called with no arguments or an argument of EV::BREAK_ONE, makes the
134innermost call to EV::loop return. 317innermost call to EV::loop return.
135 318
136When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as 319When called with an argument of EV::BREAK_ALL, all calls to EV::loop will
137fast as possible. 320return as fast as possible.
138 321
139=item $count = EV::loop_count 322When called with an argument of EV::BREAK_CANCEL, any pending break will
323be cancelled.
324
325=item $count = EV::iteration
326
327=item $count = $loop->iteration
140 328
141Return the number of times the event loop has polled for new 329Return the number of times the event loop has polled for new
142events. Sometiems useful as a generation counter. 330events. Sometimes useful as a generation counter.
143 331
144=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 332=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
333
334=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
145 335
146This function rolls together an I/O and a timer watcher for a single 336This function rolls together an I/O and a timer watcher for a single
147one-shot event without the need for managing a watcher object. 337one-shot event without the need for managing a watcher object.
148 338
149If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> 339If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
… …
155If timeout is C<undef> or negative, then there will be no 345If timeout is C<undef> or negative, then there will be no
156timeout. Otherwise a EV::timer with this value will be started. 346timeout. Otherwise a EV::timer with this value will be started.
157 347
158When an error occurs or either the timeout or I/O watcher triggers, then 348When an error occurs or either the timeout or I/O watcher triggers, then
159the callback will be called with the received event set (in general 349the callback will be called with the received event set (in general
160you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>, 350you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
161C<EV::WRITE> and C<EV::TIMEOUT>). 351C<EV::WRITE> and C<EV::TIMER>).
162 352
163EV::once doesn't return anything: the watchers stay active till either 353EV::once doesn't return anything: the watchers stay active till either
164of them triggers, then they will be stopped and freed, and the callback 354of them triggers, then they will be stopped and freed, and the callback
165invoked. 355invoked.
166 356
167=item EV::feed_fd_event ($fd, $revents) 357=item EV::feed_fd_event $fd, $revents
358
359=item $loop->feed_fd_event ($fd, $revents)
168 360
169Feed an event on a file descriptor into EV. EV will react to this call as 361Feed an event on a file descriptor into EV. EV will react to this call as
170if the readyness notifications specified by C<$revents> (a combination of 362if the readyness notifications specified by C<$revents> (a combination of
171C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. 363C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
172 364
173=item EV::feed_signal_event ($signal) 365=item EV::feed_signal_event $signal
174 366
175Feed a signal event into EV. EV will react to this call as if the signal 367Feed a signal event into the default loop. EV will react to this call as
176specified by C<$signal> had occured. 368if the signal specified by C<$signal> had occured.
177 369
178=back 370=item EV::feed_signal $signal
179 371
372Feed a signal event into EV - unlike C<EV::feed_signal_event>, this works
373regardless of which loop has registered the signal, and is mainly useful
374fro custom signal implementations.
180 375
376=item EV::set_io_collect_interval $time
377
378=item $loop->set_io_collect_interval ($time)
379
380=item EV::set_timeout_collect_interval $time
381
382=item $loop->set_timeout_collect_interval ($time)
383
384These advanced functions set the minimum block interval when polling for I/O events and the minimum
385wait interval for timer events. See the libev documentation at
386L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
387(locally installed as F<EV::libev>) for a more detailed discussion.
388
389=item $count = EV::pending_count
390
391=item $count = $loop->pending_count
392
393Returns the number of currently pending watchers.
394
395=item EV::invoke_pending
396
397=item $loop->invoke_pending
398
399Invoke all currently pending watchers.
400
401=back
402
403
181=head2 WATCHER OBJECTS 404=head1 WATCHER OBJECTS
182 405
183A watcher is an object that gets created to record your interest in some 406A watcher is an object that gets created to record your interest in some
184event. For instance, if you want to wait for STDIN to become readable, you 407event. For instance, if you want to wait for STDIN to become readable, you
185would create an EV::io watcher for that: 408would create an EV::io watcher for that:
186 409
187 my $watcher = EV::io *STDIN, EV::READ, sub { 410 my $watcher = EV::io *STDIN, EV::READ, sub {
188 my ($watcher, $revents) = @_; 411 my ($watcher, $revents) = @_;
189 warn "yeah, STDIN should not be readable without blocking!\n" 412 warn "yeah, STDIN should now be readable without blocking!\n"
190 }; 413 };
191 414
192All watchers can be active (waiting for events) or inactive (paused). Only 415All watchers can be active (waiting for events) or inactive (paused). Only
193active watchers will have their callbacks invoked. All callbacks will be 416active watchers will have their callbacks invoked. All callbacks will be
194called with at least two arguments: the watcher and a bitmask of received 417called with at least two arguments: the watcher and a bitmask of received
195events. 418events.
196 419
197Each watcher type has its associated bit in revents, so you can use the 420Each watcher type has its associated bit in revents, so you can use the
198same callback for multiple watchers. The event mask is named after the 421same callback for multiple watchers. The event mask is named after the
199type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 422type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
200EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events 423EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
201(which can set both EV::READ and EV::WRITE bits), and EV::timer (which 424(which can set both EV::READ and EV::WRITE bits).
202uses EV::TIMEOUT).
203 425
204In the rare case where one wants to create a watcher but not start it at 426In the rare case where one wants to create a watcher but not start it at
205the same time, each constructor has a variant with a trailing C<_ns> in 427the same time, each constructor has a variant with a trailing C<_ns> in
206its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. 428its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
207 429
… …
278Feed some events on this watcher into EV. EV will react to this call as if 500Feed some events on this watcher into EV. EV will react to this call as if
279the watcher had received the given C<$revents> mask. 501the watcher had received the given C<$revents> mask.
280 502
281=item $revents = $w->clear_pending 503=item $revents = $w->clear_pending
282 504
283If the watcher is pending, this function returns clears its pending status 505If the watcher is pending, this function clears its pending status and
284and returns its C<$revents> bitset (as if its callback was invoked). If the 506returns its C<$revents> bitset (as if its callback was invoked). If the
285watcher isn't pending it does nothing and returns C<0>. 507watcher isn't pending it does nothing and returns C<0>.
286 508
287=item $previous_state = $w->keepalive ($bool) 509=item $previous_state = $w->keepalive ($bool)
288 510
289Normally, C<EV::loop> will return when there are no active watchers 511Normally, C<EV::loop> will return when there are no active watchers
290(which is a "deadlock" because no progress can be made anymore). This is 512(which is a "deadlock" because no progress can be made anymore). This is
291convinient because it allows you to start your watchers (and your jobs), 513convenient because it allows you to start your watchers (and your jobs),
292call C<EV::loop> once and when it returns you know that all your jobs are 514call C<EV::loop> once and when it returns you know that all your jobs are
293finished (or they forgot to register some watchers for their task :). 515finished (or they forgot to register some watchers for their task :).
294 516
295Sometimes, however, this gets in your way, for example when you the module 517Sometimes, however, this gets in your way, for example when the module
296that calls C<EV::loop> (usually the main program) is not the same module 518that calls C<EV::loop> (usually the main program) is not the same module
297as a long-living watcher (for example a DNS client module written by 519as a long-living watcher (for example a DNS client module written by
298somebody else even). Then you might want any outstanding requests to be 520somebody else even). Then you might want any outstanding requests to be
299handled, but you would not want to keep C<EV::loop> from returning just 521handled, but you would not want to keep C<EV::loop> from returning just
300because you happen to have this long-running UDP port watcher. 522because you happen to have this long-running UDP port watcher.
301 523
302In this case you can clear the keepalive status, which means that even 524In this case you can clear the keepalive status, which means that even
303though your watcher is active, it won't keep C<EV::loop> from returning. 525though your watcher is active, it won't keep C<EV::loop> from returning.
304 526
305The initial value for keepalive is true (enabled), and you cna change it 527The initial value for keepalive is true (enabled), and you can change it
306any time. 528any time.
307 529
308Example: Register an I/O watcher for some UDP socket but do not keep the 530Example: Register an I/O watcher for some UDP socket but do not keep the
309event loop from running just because of that watcher. 531event loop from running just because of that watcher.
310 532
311 my $udp_socket = ... 533 my $udp_socket = ...
312 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 534 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
313 $udp_watcher->keepalive (0); 535 $udp_watcher->keepalive (0);
314 536
315=back 537=item $loop = $w->loop
316 538
539Return the loop that this watcher is attached to.
317 540
541=back
542
543
318=head2 WATCHER TYPES 544=head1 WATCHER TYPES
319 545
320Each of the following subsections describes a single watcher type. 546Each of the following subsections describes a single watcher type.
321 547
322=head3 I/O WATCHERS - is this file descriptor readable or writable? 548=head3 I/O WATCHERS - is this file descriptor readable or writable?
323 549
324=over 4 550=over 4
325 551
326=item $w = EV::io $fileno_or_fh, $eventmask, $callback 552=item $w = EV::io $fileno_or_fh, $eventmask, $callback
327 553
328=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 554=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
555
556=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
557
558=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
329 559
330As long as the returned watcher object is alive, call the C<$callback> 560As long as the returned watcher object is alive, call the C<$callback>
331when at least one of events specified in C<$eventmask> occurs. 561when at least one of events specified in C<$eventmask> occurs.
332 562
333The $eventmask can be one or more of these constants ORed together: 563The $eventmask can be one or more of these constants ORed together:
… …
362=over 4 592=over 4
363 593
364=item $w = EV::timer $after, $repeat, $callback 594=item $w = EV::timer $after, $repeat, $callback
365 595
366=item $w = EV::timer_ns $after, $repeat, $callback 596=item $w = EV::timer_ns $after, $repeat, $callback
597
598=item $w = $loop->timer ($after, $repeat, $callback)
599
600=item $w = $loop->timer_ns ($after, $repeat, $callback)
367 601
368Calls the callback after C<$after> seconds (which may be fractional). If 602Calls the callback after C<$after> seconds (which may be fractional). If
369C<$repeat> is non-zero, the timer will be restarted (with the $repeat 603C<$repeat> is non-zero, the timer will be restarted (with the $repeat
370value as $after) after the callback returns. 604value as $after) after the callback returns.
371 605
… …
412=over 4 646=over 4
413 647
414=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback 648=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
415 649
416=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 650=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
651
652=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
653
654=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
417 655
418Similar to EV::timer, but is not based on relative timeouts but on 656Similar to EV::timer, but is not based on relative timeouts but on
419absolute times. Apart from creating "simple" timers that trigger "at" the 657absolute times. Apart from creating "simple" timers that trigger "at" the
420specified time, it can also be used for non-drifting absolute timers and 658specified time, it can also be used for non-drifting absolute timers and
421more complex, cron-like, setups that are not adversely affected by time 659more complex, cron-like, setups that are not adversely affected by time
… …
431This time simply fires at the wallclock time C<$at> and doesn't repeat. It 669This time simply fires at the wallclock time C<$at> and doesn't repeat. It
432will not adjust when a time jump occurs, that is, if it is to be run 670will not adjust when a time jump occurs, that is, if it is to be run
433at January 1st 2011 then it will run when the system time reaches or 671at January 1st 2011 then it will run when the system time reaches or
434surpasses this time. 672surpasses this time.
435 673
436=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 674=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
437 675
438In this mode the watcher will always be scheduled to time out at the 676In this mode the watcher will always be scheduled to time out at the
439next C<$at + N * $interval> time (for some integer N) and then repeat, 677next C<$at + N * $interval> time (for some integer N) and then repeat,
440regardless of any time jumps. 678regardless of any time jumps.
441 679
… …
459time the periodic watcher gets scheduled, the reschedule callback 697time the periodic watcher gets scheduled, the reschedule callback
460($reschedule_cb) will be called with the watcher as first, and the current 698($reschedule_cb) will be called with the watcher as first, and the current
461time as second argument. 699time as second argument.
462 700
463I<This callback MUST NOT stop or destroy this or any other periodic 701I<This callback MUST NOT stop or destroy this or any other periodic
464watcher, ever>. If you need to stop it, return 1e30 and stop it 702watcher, ever, and MUST NOT call any event loop functions or methods>. If
465afterwards. 703you need to stop it, return 1e30 and stop it afterwards. You may create
704and start a C<EV::prepare> watcher for this task.
466 705
467It must return the next time to trigger, based on the passed time value 706It must return the next time to trigger, based on the passed time value
468(that is, the lowest time value larger than to the second argument). It 707(that is, the lowest time value larger than or equal to to the second
469will usually be called just before the callback will be triggered, but 708argument). It will usually be called just before the callback will be
470might be called at other times, too. 709triggered, but might be called at other times, too.
471 710
472This can be used to create very complex timers, such as a timer that 711This can be used to create very complex timers, such as a timer that
473triggers on each midnight, local time (actually 24 hours after the last 712triggers on each midnight, local time (actually 24 hours after the last
474midnight, to keep the example simple. If you know a way to do it correctly 713midnight, to keep the example simple. If you know a way to do it correctly
475in about the same space (without requiring elaborate modules), drop me a 714in about the same space (without requiring elaborate modules), drop me a
… …
511 750
512=item $w = EV::signal $signal, $callback 751=item $w = EV::signal $signal, $callback
513 752
514=item $w = EV::signal_ns $signal, $callback 753=item $w = EV::signal_ns $signal, $callback
515 754
755=item $w = $loop->signal ($signal, $callback)
756
757=item $w = $loop->signal_ns ($signal, $callback)
758
516Call the callback when $signal is received (the signal can be specified by 759Call the callback when $signal is received (the signal can be specified by
517number or by name, just as with C<kill> or C<%SIG>). 760number or by name, just as with C<kill> or C<%SIG>).
761
762Only one event loop can grab a given signal - attempting to grab the same
763signal from two EV loops will crash the program immediately or cause data
764corruption.
518 765
519EV will grab the signal for the process (the kernel only allows one 766EV will grab the signal for the process (the kernel only allows one
520component to receive a signal at a time) when you start a signal watcher, 767component to receive a signal at a time) when you start a signal watcher,
521and removes it again when you stop it. Perl does the same when you 768and removes it again when you stop it. Perl does the same when you
522add/remove callbacks to C<%SIG>, so watch out. 769add/remove callbacks to C<%SIG>, so watch out.
… …
542 789
543=head3 CHILD WATCHERS - watch out for process status changes 790=head3 CHILD WATCHERS - watch out for process status changes
544 791
545=over 4 792=over 4
546 793
547=item $w = EV::child $pid, $callback 794=item $w = EV::child $pid, $trace, $callback
548 795
549=item $w = EV::child_ns $pid, $callback 796=item $w = EV::child_ns $pid, $trace, $callback
550 797
798=item $w = $loop->child ($pid, $trace, $callback)
799
800=item $w = $loop->child_ns ($pid, $trace, $callback)
801
551Call the callback when a status change for pid C<$pid> (or any pid if 802Call the callback when a status change for pid C<$pid> (or any pid
552C<$pid> is 0) has been received. More precisely: when the process receives 803if C<$pid> is 0) has been received (a status change happens when the
804process terminates or is killed, or, when trace is true, additionally when
805it is stopped or continued). More precisely: when the process receives
553a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all 806a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
554changed/zombie children and call the callback. 807changed/zombie children and call the callback.
555 808
556It is valid (and fully supported) to install a child watcher after a child 809It is valid (and fully supported) to install a child watcher after a child
557has exited but before the event loop has started its next iteration (for 810has exited but before the event loop has started its next iteration (for
… …
564You can have as many pid watchers per pid as you want, they will all be 817You can have as many pid watchers per pid as you want, they will all be
565called. 818called.
566 819
567The C<child_ns> variant doesn't start (activate) the newly created watcher. 820The C<child_ns> variant doesn't start (activate) the newly created watcher.
568 821
569=item $w->set ($pid) 822=item $w->set ($pid, $trace)
570 823
571Reconfigures the watcher, see the constructor above for details. Can be called at 824Reconfigures the watcher, see the constructor above for details. Can be called at
572any time. 825any time.
573 826
574=item $current_pid = $w->pid 827=item $current_pid = $w->pid
575 828
576=item $old_pid = $w->pid ($new_pid)
577
578Returns the previously set process id and optionally set a new one. 829Returns the previously set process id and optionally set a new one.
579 830
580=item $exit_status = $w->rstatus 831=item $exit_status = $w->rstatus
581 832
582Return the exit/wait status (as returned by waitpid, see the waitpid entry 833Return the exit/wait status (as returned by waitpid, see the waitpid entry
… …
595=over 4 846=over 4
596 847
597=item $w = EV::stat $path, $interval, $callback 848=item $w = EV::stat $path, $interval, $callback
598 849
599=item $w = EV::stat_ns $path, $interval, $callback 850=item $w = EV::stat_ns $path, $interval, $callback
851
852=item $w = $loop->stat ($path, $interval, $callback)
853
854=item $w = $loop->stat_ns ($path, $interval, $callback)
600 855
601Call the callback when a file status change has been detected on 856Call the callback when a file status change has been detected on
602C<$path>. The C<$path> does not need to exist, changing from "path exists" 857C<$path>. The C<$path> does not need to exist, changing from "path exists"
603to "path does not exist" is a status change like any other. 858to "path does not exist" is a status change like any other.
604 859
… …
674=over 4 929=over 4
675 930
676=item $w = EV::idle $callback 931=item $w = EV::idle $callback
677 932
678=item $w = EV::idle_ns $callback 933=item $w = EV::idle_ns $callback
934
935=item $w = $loop->idle ($callback)
936
937=item $w = $loop->idle_ns ($callback)
679 938
680Call the callback when there are no other pending watchers of the same or 939Call the callback when there are no other pending watchers of the same or
681higher priority (excluding check, prepare and other idle watchers of the 940higher priority (excluding check, prepare and other idle watchers of the
682same or lower priority, of course). They are called idle watchers because 941same or lower priority, of course). They are called idle watchers because
683when the watcher is the highest priority pending event in the process, the 942when the watcher is the highest priority pending event in the process, the
… …
706 965
707=item $w = EV::prepare $callback 966=item $w = EV::prepare $callback
708 967
709=item $w = EV::prepare_ns $callback 968=item $w = EV::prepare_ns $callback
710 969
970=item $w = $loop->prepare ($callback)
971
972=item $w = $loop->prepare_ns ($callback)
973
711Call the callback just before the process would block. You can still 974Call the callback just before the process would block. You can still
712create/modify any watchers at this point. 975create/modify any watchers at this point.
713 976
714See the EV::check watcher, below, for explanations and an example. 977See the EV::check watcher, below, for explanations and an example.
715 978
… …
724 987
725=item $w = EV::check $callback 988=item $w = EV::check $callback
726 989
727=item $w = EV::check_ns $callback 990=item $w = EV::check_ns $callback
728 991
992=item $w = $loop->check ($callback)
993
994=item $w = $loop->check_ns ($callback)
995
729Call the callback just after the process wakes up again (after it has 996Call the callback just after the process wakes up again (after it has
730gathered events), but before any other callbacks have been invoked. 997gathered events), but before any other callbacks have been invoked.
731 998
732This is used to integrate other event-based software into the EV 999This can be used to integrate other event-based software into the EV
733mainloop: You register a prepare callback and in there, you create io and 1000mainloop: You register a prepare callback and in there, you create io and
734timer watchers as required by the other software. Here is a real-world 1001timer watchers as required by the other software. Here is a real-world
735example of integrating Net::SNMP (with some details left out): 1002example of integrating Net::SNMP (with some details left out):
736 1003
737 our @snmp_watcher; 1004 our @snmp_watcher;
… …
767 # make the dispatcher handle any new stuff 1034 # make the dispatcher handle any new stuff
768 ... not shown 1035 ... not shown
769 }; 1036 };
770 1037
771The callbacks of the created watchers will not be called as the watchers 1038The callbacks of the created watchers will not be called as the watchers
772are destroyed before this cna happen (remember EV::check gets called 1039are destroyed before this can happen (remember EV::check gets called
773first). 1040first).
774 1041
775The C<check_ns> variant doesn't start (activate) the newly created watcher. 1042The C<check_ns> variant doesn't start (activate) the newly created watcher.
1043
1044=item EV::CHECK constant issues
1045
1046Like all other watcher types, there is a bitmask constant for use in
1047C<$revents> and other places. The C<EV::CHECK> is special as it has
1048the same name as the C<CHECK> sub called by Perl. This doesn't cause
1049big issues on newer perls (beginning with 5.8.9), but it means thatthe
1050constant must be I<inlined>, i.e. runtime calls will not work. That means
1051that as long as you always C<use EV> and then C<EV::CHECK> you are on the
1052safe side.
776 1053
777=back 1054=back
778 1055
779 1056
780=head3 FORK WATCHERS - the audacity to resume the event loop after a fork 1057=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
… …
787 1064
788=item $w = EV::fork $callback 1065=item $w = EV::fork $callback
789 1066
790=item $w = EV::fork_ns $callback 1067=item $w = EV::fork_ns $callback
791 1068
1069=item $w = $loop->fork ($callback)
1070
1071=item $w = $loop->fork_ns ($callback)
1072
792Call the callback before the event loop is resumed in the child process 1073Call the callback before the event loop is resumed in the child process
793after a fork. 1074after a fork.
794 1075
795The C<fork_ns> variant doesn't start (activate) the newly created watcher. 1076The C<fork_ns> variant doesn't start (activate) the newly created watcher.
796 1077
797=back 1078=back
1079
1080
1081=head3 EMBED WATCHERS - when one backend isn't enough...
1082
1083This is a rather advanced watcher type that lets you embed one event loop
1084into another (currently only IO events are supported in the embedded
1085loop, other types of watchers might be handled in a delayed or incorrect
1086fashion and must not be used).
1087
1088See the libev documentation at
1089L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
1090(locally installed as F<EV::libev>) for more details.
1091
1092In short, this watcher is most useful on BSD systems without working
1093kqueue to still be able to handle a large number of sockets:
1094
1095 my $socket_loop;
1096
1097 # check wether we use SELECT or POLL _and_ KQUEUE is supported
1098 if (
1099 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
1100 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
1101 ) {
1102 # use kqueue for sockets
1103 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
1104 }
1105
1106 # use the default loop otherwise
1107 $socket_loop ||= EV::default_loop;
1108
1109=over 4
1110
1111=item $w = EV::embed $otherloop[, $callback]
1112
1113=item $w = EV::embed_ns $otherloop[, $callback]
1114
1115=item $w = $loop->embed ($otherloop[, $callback])
1116
1117=item $w = $loop->embed_ns ($otherloop[, $callback])
1118
1119Call the callback when the embedded event loop (C<$otherloop>) has any
1120I/O activity. The C<$callback> is optional: if it is missing, then the
1121embedded event loop will be managed automatically (which is recommended),
1122otherwise you have to invoke C<sweep> yourself.
1123
1124The C<embed_ns> variant doesn't start (activate) the newly created watcher.
1125
1126=back
1127
1128=head3 ASYNC WATCHERS - how to wake up another event loop
1129
1130Async watchers are provided by EV, but have little use in perl directly,
1131as perl neither supports threads running in parallel nor direct access to
1132signal handlers or other contexts where they could be of value.
1133
1134It is, however, possible to use them from the XS level.
1135
1136Please see the libev documentation for further details.
1137
1138=over 4
1139
1140=item $w = EV::async $callback
1141
1142=item $w = EV::async_ns $callback
1143
1144=item $w = $loop->async ($callback)
1145
1146=item $w = $loop->async_ns ($callback)
1147
1148=item $w->send
1149
1150=item $bool = $w->async_pending
1151
1152=back
1153
1154=head3 CLEANUP WATCHERS - how to clean up when the event loop goes away
1155
1156Cleanup watchers are not supported on the Perl level, they can only be
1157used via XS currently.
798 1158
799 1159
800=head1 PERL SIGNALS 1160=head1 PERL SIGNALS
801 1161
802While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour 1162While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
… …
811to be called on every event loop iteration by installing a C<EV::check> 1171to be called on every event loop iteration by installing a C<EV::check>
812watcher: 1172watcher:
813 1173
814 my $async_check = EV::check sub { }; 1174 my $async_check = EV::check sub { };
815 1175
816This ensures that perl shortly gets into control for a short time, and 1176This ensures that perl gets into control for a short time to handle any
817also ensures slower overall operation. 1177pending signals, and also ensures (slightly) slower overall operation.
818 1178
819=head1 THREADS 1179=head1 ITHREADS
820 1180
821Threads are not supported by this module in any way. Perl pseudo-threads 1181Ithreads are not supported by this module in any way. Perl pseudo-threads
822is evil stuff and must die. As soon as Perl gains real threads I will work 1182is evil stuff and must die. Real threads as provided by Coro are fully
823on thread support for it. 1183supported (and enhanced support is available via L<Coro::EV>).
824 1184
825=head1 FORK 1185=head1 FORK
826 1186
827Most of the "improved" event delivering mechanisms of modern operating 1187Most of the "improved" event delivering mechanisms of modern operating
828systems have quite a few problems with fork(2) (to put it bluntly: it is 1188systems have quite a few problems with fork(2) (to put it bluntly: it is
… …
850 1210
8511; 12111;
852 1212
853=head1 SEE ALSO 1213=head1 SEE ALSO
854 1214
1215L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS>
855L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as 1216(asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as event
856event loop), L<Coro::EV> (efficient coroutines with EV). 1217loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient thread
1218integration), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1219event-loop agnostic and portable event driven programming.
857 1220
858=head1 AUTHOR 1221=head1 AUTHOR
859 1222
860 Marc Lehmann <schmorp@schmorp.de> 1223 Marc Lehmann <schmorp@schmorp.de>
861 http://home.schmorp.de/ 1224 http://home.schmorp.de/
862 1225
863=cut 1226=cut
864 1227

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