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Revision 1.86 by root, Wed Apr 2 11:00:58 2008 UTC vs.
Revision 1.138 by root, Sun May 6 16:30:27 2012 UTC

… …
2 2
3EV - perl interface to libev, a high performance full-featured event loop 3EV - perl interface to libev, a high performance full-featured event loop
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use EV; 7 use EV;
8
9 # TIMERS
10
11 my $w = EV::timer 2, 0, sub {
12 warn "is called after 2s";
13 };
14
15 my $w = EV::timer 2, 2, sub {
16 warn "is called roughly every 2s (repeat = 2)";
17 };
18
19 undef $w; # destroy event watcher again
20
21 my $w = EV::periodic 0, 60, 0, sub {
22 warn "is called every minute, on the minute, exactly";
23 };
24
25 # IO
26
27 my $w = EV::io *STDIN, EV::READ, sub {
28 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29 warn "stdin is readable, you entered: ", <STDIN>;
30 };
31
32 # SIGNALS
33
34 my $w = EV::signal 'QUIT', sub {
35 warn "sigquit received\n";
36 };
37
38 # CHILD/PID STATUS CHANGES
8 39
9 # TIMERS 40 my $w = EV::child 666, 0, sub {
41 my ($w, $revents) = @_;
42 my $status = $w->rstatus;
43 };
10 44
11 my $w = EV::timer 2, 0, sub {
12 warn "is called after 2s";
13 };
14
15 my $w = EV::timer 2, 2, sub {
16 warn "is called roughly every 2s (repeat = 2)";
17 };
18
19 undef $w; # destroy event watcher again
20
21 my $w = EV::periodic 0, 60, 0, sub {
22 warn "is called every minute, on the minute, exactly";
23 };
24
25 # IO
26
27 my $w = EV::io *STDIN, EV::READ, sub {
28 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29 warn "stdin is readable, you entered: ", <STDIN>;
30 };
31
32 # SIGNALS
33
34 my $w = EV::signal 'QUIT', sub {
35 warn "sigquit received\n";
36 };
37
38 # CHILD/PID STATUS CHANGES
39
40 my $w = EV::child 666, 0, sub {
41 my ($w, $revents) = @_;
42 my $status = $w->rstatus;
43 };
44
45 # STAT CHANGES 45 # STAT CHANGES
46 my $w = EV::stat "/etc/passwd", 10, sub { 46 my $w = EV::stat "/etc/passwd", 10, sub {
47 my ($w, $revents) = @_; 47 my ($w, $revents) = @_;
48 warn $w->path, " has changed somehow.\n"; 48 warn $w->path, " has changed somehow.\n";
49 }; 49 };
50 50
51 # MAINLOOP 51 # MAINLOOP
52 EV::loop; # loop until EV::unloop is called or all watchers stop 52 EV::run; # loop until EV::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 = '3.2'; 124 our $VERSION = '4.11';
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 =
… …
105default loop as this is fastest (perl-wise), best supported by other 156default loop as this is fastest (perl-wise), best supported by other
106modules (e.g. AnyEvent or Coro) and most portable event loop. 157modules (e.g. AnyEvent or Coro) and most portable event loop.
107 158
108For specific programs you can create additional event loops dynamically. 159For specific programs you can create additional event loops dynamically.
109 160
110=over 4 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.
111 166
167=over 4
168
112=item $loop = new EV::loop [$flags] 169=item $loop = new EV::Loop [$flags]
113 170
114Create a new event loop as per the specified flags. Please refer to the 171Create a new event loop as per the specified flags. Please refer to
115C<ev_loop_new ()> function description in the libev documentation 172the C<ev_loop_new ()> function description in the libev documentation
116(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>) 173(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
117for more info. 174or locally-installed as F<EV::libev> manpage) for more info.
118 175
119The loop will automatically be destroyed when it is no longer referenced 176The loop will automatically be destroyed when it is no longer referenced
120by any watcher and the loop object goes out of scope. 177by any watcher and the loop object goes out of scope.
121 178
122Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop 179If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
123is protected by this module. 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.
124 183
125=item $loop->loop_fork 184=item $loop->loop_fork
126 185
127Must be called after a fork in the child, before entering or continuing 186Must be called after a fork in the child, before entering or continuing
128the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls 187the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
129this fucntion automatically, at some performance loss (refer to the libev 188this function automatically, at some performance loss (refer to the libev
130documentation). 189documentation).
131 190
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
132=item $loop = EV::default_loop [$flags] 197=item $loop = EV::default_loop [$flags]
133 198
134Return the default loop (which is a singleton object). 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.
135 204
136=back 205=back
137 206
138 207
139=head1 BASIC INTERFACE 208=head1 BASIC INTERFACE
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169=item $time = EV::now 238=item $time = EV::now
170 239
171=item $time = $loop->now 240=item $time = $loop->now
172 241
173Returns the time the last event loop iteration has been started. This 242Returns the time the last event loop iteration has been started. This
174is 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
175usually faster then calling EV::time. 244usually faster then calling EV::time.
176 245
246=item EV::now_update
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
177=item $backend = EV::backend 288=item $backend = EV::backend
178 289
179=item $backend = $loop->backend 290=item $backend = $loop->backend
180 291
181Returns an integer describing the backend used by libev (EV::METHOD_SELECT 292Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
182or EV::METHOD_EPOLL). 293or EV::BACKEND_EPOLL).
183 294
184=item EV::loop [$flags] 295=item $active = EV::run [$flags]
185 296
186=item $loop->loop ([$flags]) 297=item $active = $loop->run ([$flags])
187 298
188Begin checking for events and calling callbacks. It returns when a 299Begin checking for events and calling callbacks. It returns when a
189callback 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".
190 305
191The $flags argument can be one of the following: 306The $flags argument can be one of the following:
192 307
193 0 as above 308 0 as above
194 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 309 EV::RUN_ONCE block at most once (wait, but do not loop)
195 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 310 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
196 311
197=item EV::unloop [$how] 312=item EV::break [$how]
198 313
199=item $loop->unloop ([$how]) 314=item $loop->break ([$how])
200 315
201When 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
202innermost call to EV::loop return. 317innermost call to EV::loop return.
203 318
204When 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
205fast as possible. 320return as fast as possible.
206 321
207=item $count = EV::loop_count 322When called with an argument of EV::BREAK_CANCEL, any pending break will
323be cancelled.
208 324
325=item $count = EV::iteration
326
209=item $count = $loop->loop_count 327=item $count = $loop->iteration
210 328
211Return the number of times the event loop has polled for new 329Return the number of times the event loop has polled for new
212events. Sometiems useful as a generation counter. 330events. Sometimes useful as a generation counter.
213 331
214=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 332=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
215 333
216=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 334=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
217 335
… …
228timeout. Otherwise a EV::timer with this value will be started. 346timeout. Otherwise a EV::timer with this value will be started.
229 347
230When 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
231the callback will be called with the received event set (in general 349the callback will be called with the received event set (in general
232you 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>,
233C<EV::WRITE> and C<EV::TIMEOUT>). 351C<EV::WRITE> and C<EV::TIMER>).
234 352
235EV::once doesn't return anything: the watchers stay active till either 353EV::once doesn't return anything: the watchers stay active till either
236of 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
237invoked. 355invoked.
238 356
239=item EV::feed_fd_event ($fd, $revents) 357=item EV::feed_fd_event $fd, $revents
240 358
241=item $loop->feed_fd_event ($fd, $revents) 359=item $loop->feed_fd_event ($fd, $revents)
242 360
243Feed an event on a file descriptor into EV. EV will react to this call as 361Feed an event on a file descriptor into EV. EV will react to this call as
244if the readyness notifications specified by C<$revents> (a combination of 362if the readyness notifications specified by C<$revents> (a combination of
245C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. 363C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
246 364
247=item EV::feed_signal_event ($signal) 365=item EV::feed_signal_event $signal
248 366
249Feed a signal event into EV. EV will react to this call as if the signal 367Feed a signal event into the default loop. EV will react to this call as
250specified by C<$signal> had occured. 368if the signal specified by C<$signal> had occured.
369
370=item EV::feed_signal $signal
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.
251 375
252=item EV::set_io_collect_interval $time 376=item EV::set_io_collect_interval $time
253 377
254=item $loop->set_io_collect_interval ($time) 378=item $loop->set_io_collect_interval ($time)
255 379
… …
257 381
258=item $loop->set_timeout_collect_interval ($time) 382=item $loop->set_timeout_collect_interval ($time)
259 383
260These advanced functions set the minimum block interval when polling for I/O events and the minimum 384These advanced functions set the minimum block interval when polling for I/O events and the minimum
261wait interval for timer events. See the libev documentation at 385wait interval for timer events. See the libev documentation at
262L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> for 386L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
263a more detailed discussion. 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.
264 400
265=back 401=back
266 402
267 403
268=head1 WATCHER OBJECTS 404=head1 WATCHER OBJECTS
269 405
270A 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
271event. 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
272would create an EV::io watcher for that: 408would create an EV::io watcher for that:
273 409
274 my $watcher = EV::io *STDIN, EV::READ, sub { 410 my $watcher = EV::io *STDIN, EV::READ, sub {
275 my ($watcher, $revents) = @_; 411 my ($watcher, $revents) = @_;
276 warn "yeah, STDIN should now be readable without blocking!\n" 412 warn "yeah, STDIN should now be readable without blocking!\n"
277 }; 413 };
278 414
279All watchers can be active (waiting for events) or inactive (paused). Only 415All watchers can be active (waiting for events) or inactive (paused). Only
280active watchers will have their callbacks invoked. All callbacks will be 416active watchers will have their callbacks invoked. All callbacks will be
281called 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
282events. 418events.
283 419
284Each 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
285same callback for multiple watchers. The event mask is named after the 421same callback for multiple watchers. The event mask is named after the
286type, 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,
287EV::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
288(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).
289uses EV::TIMEOUT).
290 425
291In 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
292the 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
293its 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.
294 429
… …
373 508
374=item $previous_state = $w->keepalive ($bool) 509=item $previous_state = $w->keepalive ($bool)
375 510
376Normally, C<EV::loop> will return when there are no active watchers 511Normally, C<EV::loop> will return when there are no active watchers
377(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
378convinient because it allows you to start your watchers (and your jobs), 513convenient because it allows you to start your watchers (and your jobs),
379call 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
380finished (or they forgot to register some watchers for their task :). 515finished (or they forgot to register some watchers for their task :).
381 516
382Sometimes, however, this gets in your way, for example when the module 517Sometimes, however, this gets in your way, for example when the module
383that 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
… …
387because you happen to have this long-running UDP port watcher. 522because you happen to have this long-running UDP port watcher.
388 523
389In 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
390though 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.
391 526
392The 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
393any time. 528any time.
394 529
395Example: 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
396event loop from running just because of that watcher. 531event loop from running just because of that watcher.
397 532
398 my $udp_socket = ... 533 my $udp_socket = ...
399 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 534 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
400 $1000udp_watcher->keepalive (0); 535 $udp_watcher->keepalive (0);
401 536
402=item $loop = $w->loop 537=item $loop = $w->loop
403 538
404Return the loop that this watcher is attached to. 539Return the loop that this watcher is attached to.
405 540
… …
562time the periodic watcher gets scheduled, the reschedule callback 697time the periodic watcher gets scheduled, the reschedule callback
563($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
564time as second argument. 699time as second argument.
565 700
566I<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
567watcher, 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
568afterwards. 703you need to stop it, return 1e30 and stop it afterwards. You may create
704and start a C<EV::prepare> watcher for this task.
569 705
570It 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
571(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
572will usually be called just before the callback will be triggered, but 708argument). It will usually be called just before the callback will be
573might be called at other times, too. 709triggered, but might be called at other times, too.
574 710
575This 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
576triggers on each midnight, local time (actually 24 hours after the last 712triggers on each midnight, local time (actually 24 hours after the last
577midnight, 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
578in about the same space (without requiring elaborate modules), drop me a 714in about the same space (without requiring elaborate modules), drop me a
… …
614 750
615=item $w = EV::signal $signal, $callback 751=item $w = EV::signal $signal, $callback
616 752
617=item $w = EV::signal_ns $signal, $callback 753=item $w = EV::signal_ns $signal, $callback
618 754
755=item $w = $loop->signal ($signal, $callback)
756
757=item $w = $loop->signal_ns ($signal, $callback)
758
619Call 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
620number 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.
621 765
622EV 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
623component 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,
624and 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
625add/remove callbacks to C<%SIG>, so watch out. 769add/remove callbacks to C<%SIG>, so watch out.
… …
850=item $w = $loop->check_ns ($callback) 994=item $w = $loop->check_ns ($callback)
851 995
852Call 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
853gathered events), but before any other callbacks have been invoked. 997gathered events), but before any other callbacks have been invoked.
854 998
855This is used to integrate other event-based software into the EV 999This can be used to integrate other event-based software into the EV
856mainloop: 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
857timer 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
858example of integrating Net::SNMP (with some details left out): 1002example of integrating Net::SNMP (with some details left out):
859 1003
860 our @snmp_watcher; 1004 our @snmp_watcher;
… …
890 # make the dispatcher handle any new stuff 1034 # make the dispatcher handle any new stuff
891 ... not shown 1035 ... not shown
892 }; 1036 };
893 1037
894The 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
895are destroyed before this cna happen (remember EV::check gets called 1039are destroyed before this can happen (remember EV::check gets called
896first). 1040first).
897 1041
898The 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.
899 1053
900=back 1054=back
901 1055
902 1056
903=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
… …
931loop, other types of watchers might be handled in a delayed or incorrect 1085loop, other types of watchers might be handled in a delayed or incorrect
932fashion and must not be used). 1086fashion and must not be used).
933 1087
934See the libev documentation at 1088See the libev documentation at
935L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> 1089L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
936for more details. 1090(locally installed as F<EV::libev>) for more details.
937 1091
938In short, this watcher is most useful on BSD systems without working 1092In short, this watcher is most useful on BSD systems without working
939kqueue to still be able to handle a large number of sockets: 1093kqueue to still be able to handle a large number of sockets:
940 1094
941 my $socket_loop; 1095 my $socket_loop;
942 1096
943 # check wether we use SELECT or POLL _and_ KQUEUE is supported 1097 # check wether we use SELECT or POLL _and_ KQUEUE is supported
944 if ( 1098 if (
945 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 1099 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
946 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 1100 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
947 ) { 1101 ) {
948 # use kqueue for sockets 1102 # use kqueue for sockets
949 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 1103 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
950 } 1104 }
951 1105
952 # use the default loop otherwise 1106 # use the default loop otherwise
953 $socket_loop ||= EV::default_loop; 1107 $socket_loop ||= EV::default_loop;
954 1108
955=over 4 1109=over 4
956 1110
957=item $w = EV::embed $otherloop, $callback 1111=item $w = EV::embed $otherloop[, $callback]
958 1112
959=item $w = EV::embed_ns $otherloop, $callback 1113=item $w = EV::embed_ns $otherloop[, $callback]
960 1114
961=item $w = $loop->embed ($otherloop, $callback) 1115=item $w = $loop->embed ($otherloop[, $callback])
962 1116
963=item $w = $loop->embed_ns ($otherloop, $callback) 1117=item $w = $loop->embed_ns ($otherloop[, $callback])
964 1118
965Call the callback when the embedded event loop (C<$otherloop>) has any 1119Call the callback when the embedded event loop (C<$otherloop>) has any
966I/O activity. The C<$callback> should alwas be specified as C<undef> in 1120I/O activity. The C<$callback> is optional: if it is missing, then the
967this version of EV, which means the embedded event loop will be managed 1121embedded event loop will be managed automatically (which is recommended),
968automatically. 1122otherwise you have to invoke C<sweep> yourself.
969 1123
970The C<embed_ns> variant doesn't start (activate) the newly created watcher. 1124The C<embed_ns> variant doesn't start (activate) the newly created watcher.
971 1125
972=back 1126=back
973 1127
974=head3 ASYNC WATCHERS - how to wake up another event loop 1128=head3 ASYNC WATCHERS - how to wake up another event loop
975 1129
976Async watchers are provided by EV, but have little use in perl directly, as perl 1130Async watchers are provided by EV, but have little use in perl directly,
977neither supports threads nor direct access to signal handlers or other 1131as perl neither supports threads running in parallel nor direct access to
978contexts where they could be of value. 1132signal handlers or other contexts where they could be of value.
979 1133
980It is, however, possible to use them from the XS level. 1134It is, however, possible to use them from the XS level.
981 1135
982Please see the libev documentation for further details. 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.
983 1158
984 1159
985=head1 PERL SIGNALS 1160=head1 PERL SIGNALS
986 1161
987While 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
… …
999 my $async_check = EV::check sub { }; 1174 my $async_check = EV::check sub { };
1000 1175
1001This ensures that perl gets into control for a short time to handle any 1176This ensures that perl gets into control for a short time to handle any
1002pending signals, and also ensures (slightly) slower overall operation. 1177pending signals, and also ensures (slightly) slower overall operation.
1003 1178
1004=head1 THREADS 1179=head1 ITHREADS
1005 1180
1006Threads 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
1007is 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
1008on thread support for it. 1183supported (and enhanced support is available via L<Coro::EV>).
1009 1184
1010=head1 FORK 1185=head1 FORK
1011 1186
1012Most of the "improved" event delivering mechanisms of modern operating 1187Most of the "improved" event delivering mechanisms of modern operating
1013systems 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
… …
1035 1210
10361; 12111;
1037 1212
1038=head1 SEE ALSO 1213=head1 SEE ALSO
1039 1214
1215L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS>
1040L<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
1041event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient 1217loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient thread
1042coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP). 1218integration), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1219event-loop agnostic and portable event driven programming.
1043 1220
1044=head1 AUTHOR 1221=head1 AUTHOR
1045 1222
1046 Marc Lehmann <schmorp@schmorp.de> 1223 Marc Lehmann <schmorp@schmorp.de>
1047 http://home.schmorp.de/ 1224 http://home.schmorp.de/
1048 1225
1049=cut 1226=cut
1050 1227

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