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Revision 1.73 by root, Fri Dec 21 05:10:01 2007 UTC vs.
Revision 1.139 by root, Fri Mar 1 11:20:07 2013 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::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";
92 144
93=head1 EVENT LOOPS 145=head1 EVENT LOOPS
… …
102selecting a working backend (which for example rules out kqueue on most 154selecting a working backend (which for example rules out kqueue on most
103BSDs). Modules should, unless they have "special needs" always use the 155BSDs). Modules should, unless they have "special needs" always use the
104default loop as this is fastest (perl-wise), best supported by other 156default loop as this is fastest (perl-wise), best supported by other
105modules (e.g. AnyEvent or Coro) and most portable event loop. 157modules (e.g. AnyEvent or Coro) and most portable event loop.
106 158
107For specific programs you cna create additional event loops dynamically. 159For specific programs you can create additional event loops dynamically.
108 160
109=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.
110 166
167=over 4
168
111=item $loop = new EV::loop [$flags] 169=item $loop = new EV::Loop [$flags]
112 170
113Create 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
114C<ev_loop_new ()> function description in the libev documentation 172the 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>) 173(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
116for more info. 174or locally-installed as F<EV::libev> manpage) for more info.
117 175
118The loop will automatically be destroyed when it is no longer referenced 176The loop will automatically be destroyed when it is no longer referenced
119by any watcher and the loop object goes out of scope. 177by any watcher and the loop object goes out of scope.
120 178
121Using 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>
122is 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.
123 183
124=item $loop->loop_fork 184=item $loop->loop_fork
125 185
126Must 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
127the 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
128this fucntion automatically, at some performance loss (refer to the libev 188this function automatically, at some performance loss (refer to the libev
129documentation). 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.
130 204
131=back 205=back
132 206
133 207
134=head1 BASIC INTERFACE 208=head1 BASIC INTERFACE
… …
141throws an exception (with $@ containing the error). The default prints an 215throws an exception (with $@ containing the error). The default prints an
142informative message and continues. 216informative message and continues.
143 217
144If this callback throws an exception it will be silently ignored. 218If this callback throws an exception it will be silently ignored.
145 219
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
146=item $time = EV::time 234=item $time = EV::time
147 235
148Returns the current time in (fractional) seconds since the epoch. 236Returns the current time in (fractional) seconds since the epoch.
149 237
150=item $time = EV::now 238=item $time = EV::now
151 239
152=item $time = $loop->now 240=item $time = $loop->now
153 241
154Returns the time the last event loop iteration has been started. This 242Returns 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 243is the time that (relative) timers are based on, and referring to it is
156usually faster then calling EV::time. 244usually faster then calling EV::time.
157 245
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
158=item $backend = EV::backend 288=item $backend = EV::backend
159 289
160=item $backend = $loop->backend 290=item $backend = $loop->backend
161 291
162Returns an integer describing the backend used by libev (EV::METHOD_SELECT 292Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
163or EV::METHOD_EPOLL). 293or EV::BACKEND_EPOLL).
164 294
165=item EV::loop [$flags] 295=item $active = EV::run [$flags]
166 296
167=item $loop->loop ([$flags]) 297=item $active = $loop->run ([$flags])
168 298
169Begin checking for events and calling callbacks. It returns when a 299Begin checking for events and calling callbacks. It returns when a
170callback 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".
171 305
172The $flags argument can be one of the following: 306The $flags argument can be one of the following:
173 307
174 0 as above 308 0 as above
175 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 309 EV::RUN_ONCE block at most once (wait, but do not loop)
176 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 310 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
177 311
178=item EV::unloop [$how] 312=item EV::break [$how]
179 313
180=item $loop->unloop ([$how]) 314=item $loop->break ([$how])
181 315
182When 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
183innermost call to EV::loop return. 317innermost call to EV::loop return.
184 318
185When 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
186fast as possible. 320return as fast as possible.
187 321
188=item $count = EV::loop_count 322When called with an argument of EV::BREAK_CANCEL, any pending break will
323be cancelled.
189 324
325=item $count = EV::iteration
326
190=item $count = $loop->loop_count 327=item $count = $loop->iteration
191 328
192Return the number of times the event loop has polled for new 329Return the number of times the event loop has polled for new
193events. Sometiems useful as a generation counter. 330events. Sometimes useful as a generation counter.
194 331
195=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 332=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
196 333
197=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 334=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
198 335
… …
208If timeout is C<undef> or negative, then there will be no 345If timeout is C<undef> or negative, then there will be no
209timeout. Otherwise a EV::timer with this value will be started. 346timeout. Otherwise a EV::timer with this value will be started.
210 347
211When 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
212the callback will be called with the received event set (in general 349the 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>, 350you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
214C<EV::WRITE> and C<EV::TIMEOUT>). 351C<EV::WRITE> and C<EV::TIMER>).
215 352
216EV::once doesn't return anything: the watchers stay active till either 353EV::once doesn't return anything: the watchers stay active till either
217of 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
218invoked. 355invoked.
219 356
220=item EV::feed_fd_event ($fd, $revents) 357=item EV::feed_fd_event $fd, $revents
221 358
222=item $loop->feed_fd_event ($fd, $revents) 359=item $loop->feed_fd_event ($fd, $revents)
223 360
224Feed an event on a file descriptor into EV. EV will react to this call as 361Feed an event on a file descriptor into EV. EV will react to this call as
225if the readyness notifications specified by C<$revents> (a combination of 362if the readyness notifications specified by C<$revents> (a combination of
226C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. 363C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
227 364
228=item EV::feed_signal_event ($signal) 365=item EV::feed_signal_event $signal
229 366
230Feed a signal event into EV. EV will react to this call as if the signal 367Feed a signal event into the default loop. EV will react to this call as
231specified by C<$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.
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.
232 400
233=back 401=back
234 402
235 403
236=head1 WATCHER OBJECTS 404=head1 WATCHER OBJECTS
237 405
238A 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
239event. 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
240would create an EV::io watcher for that: 408would create an EV::io watcher for that:
241 409
242 my $watcher = EV::io *STDIN, EV::READ, sub { 410 my $watcher = EV::io *STDIN, EV::READ, sub {
243 my ($watcher, $revents) = @_; 411 my ($watcher, $revents) = @_;
244 warn "yeah, STDIN should not be readable without blocking!\n" 412 warn "yeah, STDIN should now be readable without blocking!\n"
245 }; 413 };
246 414
247All watchers can be active (waiting for events) or inactive (paused). Only 415All watchers can be active (waiting for events) or inactive (paused). Only
248active watchers will have their callbacks invoked. All callbacks will be 416active watchers will have their callbacks invoked. All callbacks will be
249called 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
250events. 418events.
251 419
252Each 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
253same callback for multiple watchers. The event mask is named after the 421same callback for multiple watchers. The event mask is named after the
254type, 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,
255EV::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
256(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).
257uses EV::TIMEOUT).
258 425
259In 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
260the 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
261its 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.
262 429
… …
333Feed 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
334the watcher had received the given C<$revents> mask. 501the watcher had received the given C<$revents> mask.
335 502
336=item $revents = $w->clear_pending 503=item $revents = $w->clear_pending
337 504
338If the watcher is pending, this function returns clears its pending status 505If the watcher is pending, this function clears its pending status and
339and returns its C<$revents> bitset (as if its callback was invoked). If the 506returns its C<$revents> bitset (as if its callback was invoked). If the
340watcher isn't pending it does nothing and returns C<0>. 507watcher isn't pending it does nothing and returns C<0>.
341 508
342=item $previous_state = $w->keepalive ($bool) 509=item $previous_state = $w->keepalive ($bool)
343 510
344Normally, C<EV::loop> will return when there are no active watchers 511Normally, C<EV::loop> will return when there are no active watchers
345(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
346convinient because it allows you to start your watchers (and your jobs), 513convenient 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 514call C<EV::loop> once and when it returns you know that all your jobs are
348finished (or they forgot to register some watchers for their task :). 515finished (or they forgot to register some watchers for their task :).
349 516
350Sometimes, however, this gets in your way, for example when you the module 517Sometimes, 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 518that calls C<EV::loop> (usually the main program) is not the same module
352as 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
353somebody else even). Then you might want any outstanding requests to be 520somebody 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 521handled, but you would not want to keep C<EV::loop> from returning just
355because you happen to have this long-running UDP port watcher. 522because you happen to have this long-running UDP port watcher.
356 523
357In 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
358though 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.
359 526
360The 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
361any time. 528any time.
362 529
363Example: 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
364event loop from running just because of that watcher. 531event loop from running just because of that watcher.
365 532
366 my $udp_socket = ... 533 my $udp_socket = ...
367 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 534 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
368 $udp_watcher->keepalive (0); 535 $udp_watcher->keepalive (0);
369 536
537=item $loop = $w->loop
538
539Return the loop that this watcher is attached to.
540
370=back 541=back
371 542
372 543
373=head1 WATCHER TYPES 544=head1 WATCHER TYPES
374 545
… …
380 551
381=item $w = EV::io $fileno_or_fh, $eventmask, $callback 552=item $w = EV::io $fileno_or_fh, $eventmask, $callback
382 553
383=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 554=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
384 555
385=item $w = $loop->io 8$fileno_or_fh, $eventmask, $callback) 556=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
386 557
387=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback) 558=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
388 559
389As long as the returned watcher object is alive, call the C<$callback> 560As long as the returned watcher object is alive, call the C<$callback>
390when at least one of events specified in C<$eventmask> occurs. 561when at least one of events specified in C<$eventmask> occurs.
… …
498This time simply fires at the wallclock time C<$at> and doesn't repeat. It 669This time simply fires at the wallclock time C<$at> and doesn't repeat. It
499will not adjust when a time jump occurs, that is, if it is to be run 670will not adjust when a time jump occurs, that is, if it is to be run
500at January 1st 2011 then it will run when the system time reaches or 671at January 1st 2011 then it will run when the system time reaches or
501surpasses this time. 672surpasses this time.
502 673
503=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 674=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
504 675
505In this mode the watcher will always be scheduled to time out at the 676In this mode the watcher will always be scheduled to time out at the
506next C<$at + N * $interval> time (for some integer N) and then repeat, 677next C<$at + N * $interval> time (for some integer N) and then repeat,
507regardless of any time jumps. 678regardless of any time jumps.
508 679
… …
526time the periodic watcher gets scheduled, the reschedule callback 697time the periodic watcher gets scheduled, the reschedule callback
527($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
528time as second argument. 699time as second argument.
529 700
530I<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
531watcher, 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
532afterwards. 703you need to stop it, return 1e30 and stop it afterwards. You may create
704and start a C<EV::prepare> watcher for this task.
533 705
534It 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
535(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
536will usually be called just before the callback will be triggered, but 708argument). It will usually be called just before the callback will be
537might be called at other times, too. 709triggered, but might be called at other times, too.
538 710
539This 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
540triggers on each midnight, local time (actually 24 hours after the last 712triggers on each midnight, local time (actually 24 hours after the last
541midnight, 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
542in about the same space (without requiring elaborate modules), drop me a 714in about the same space (without requiring elaborate modules), drop me a
… …
578 750
579=item $w = EV::signal $signal, $callback 751=item $w = EV::signal $signal, $callback
580 752
581=item $w = EV::signal_ns $signal, $callback 753=item $w = EV::signal_ns $signal, $callback
582 754
755=item $w = $loop->signal ($signal, $callback)
756
757=item $w = $loop->signal_ns ($signal, $callback)
758
583Call 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
584number 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.
585 765
586EV 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
587component 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,
588and 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
589add/remove callbacks to C<%SIG>, so watch out. 769add/remove callbacks to C<%SIG>, so watch out.
… …
609 789
610=head3 CHILD WATCHERS - watch out for process status changes 790=head3 CHILD WATCHERS - watch out for process status changes
611 791
612=over 4 792=over 4
613 793
614=item $w = EV::child $pid, $callback 794=item $w = EV::child $pid, $trace, $callback
615 795
616=item $w = EV::child_ns $pid, $callback 796=item $w = EV::child_ns $pid, $trace, $callback
617 797
618=item $w = $loop->child ($pid, $callback) 798=item $w = $loop->child ($pid, $trace, $callback)
619 799
620=item $w = $loop->child_ns ($pid, $callback) 800=item $w = $loop->child_ns ($pid, $trace, $callback)
621 801
622Call the callback when a status change for pid C<$pid> (or any pid if 802Call the callback when a status change for pid C<$pid> (or any pid
623C<$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
624a 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
625changed/zombie children and call the callback. 807changed/zombie children and call the callback.
626 808
627It 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
628has 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
… …
635You 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
636called. 818called.
637 819
638The 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.
639 821
640=item $w->set ($pid) 822=item $w->set ($pid, $trace)
641 823
642Reconfigures 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
643any time. 825any time.
644 826
645=item $current_pid = $w->pid 827=item $current_pid = $w->pid
646
647=item $old_pid = $w->pid ($new_pid)
648 828
649Returns the previously set process id and optionally set a new one. 829Returns the previously set process id and optionally set a new one.
650 830
651=item $exit_status = $w->rstatus 831=item $exit_status = $w->rstatus
652 832
… …
787 967
788=item $w = EV::prepare_ns $callback 968=item $w = EV::prepare_ns $callback
789 969
790=item $w = $loop->prepare ($callback) 970=item $w = $loop->prepare ($callback)
791 971
792=item $w = $loop->prepare_ns 8$callback) 972=item $w = $loop->prepare_ns ($callback)
793 973
794Call the callback just before the process would block. You can still 974Call the callback just before the process would block. You can still
795create/modify any watchers at this point. 975create/modify any watchers at this point.
796 976
797See the EV::check watcher, below, for explanations and an example. 977See the EV::check watcher, below, for explanations and an example.
… …
814=item $w = $loop->check_ns ($callback) 994=item $w = $loop->check_ns ($callback)
815 995
816Call 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
817gathered events), but before any other callbacks have been invoked. 997gathered events), but before any other callbacks have been invoked.
818 998
819This is used to integrate other event-based software into the EV 999This can be used to integrate other event-based software into the EV
820mainloop: 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
821timer 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
822example of integrating Net::SNMP (with some details left out): 1002example of integrating Net::SNMP (with some details left out):
823 1003
824 our @snmp_watcher; 1004 our @snmp_watcher;
… …
854 # make the dispatcher handle any new stuff 1034 # make the dispatcher handle any new stuff
855 ... not shown 1035 ... not shown
856 }; 1036 };
857 1037
858The 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
859are destroyed before this cna happen (remember EV::check gets called 1039are destroyed before this can happen (remember EV::check gets called
860first). 1040first).
861 1041
862The 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.
863 1053
864=back 1054=back
865 1055
866 1056
867=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
… …
884after a fork. 1074after a fork.
885 1075
886The 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.
887 1077
888=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.
889 1158
890 1159
891=head1 PERL SIGNALS 1160=head1 PERL SIGNALS
892 1161
893While 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
… …
902to 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>
903watcher: 1172watcher:
904 1173
905 my $async_check = EV::check sub { }; 1174 my $async_check = EV::check sub { };
906 1175
907This 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
908also ensures slower overall operation. 1177pending signals, and also ensures (slightly) slower overall operation.
909 1178
910=head1 THREADS 1179=head1 ITHREADS
911 1180
912Threads 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
913is 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
914on thread support for it. 1183supported (and enhanced support is available via L<Coro::EV>).
915 1184
916=head1 FORK 1185=head1 FORK
917 1186
918Most of the "improved" event delivering mechanisms of modern operating 1187Most of the "improved" event delivering mechanisms of modern operating
919systems 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
… …
941 1210
9421; 12111;
943 1212
944=head1 SEE ALSO 1213=head1 SEE ALSO
945 1214
1215L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS>
946L<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
947event 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
948coroutines 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.
949 1220
950=head1 AUTHOR 1221=head1 AUTHOR
951 1222
952 Marc Lehmann <schmorp@schmorp.de> 1223 Marc Lehmann <schmorp@schmorp.de>
953 http://home.schmorp.de/ 1224 http://home.schmorp.de/
954 1225
955=cut 1226=cut
956 1227

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