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Revision 1.73 by root, Fri Dec 21 05:10:01 2007 UTC vs.
Revision 1.136 by root, Thu Jan 19 17:55:23 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 $w = EV::child 666, sub {
41 my ($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 = '4.10';
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
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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
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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 EV::run [$flags]
166 296
167=item $loop->loop ([$flags]) 297=item $loop->run ([$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.
171 301
172The $flags argument can be one of the following: 302The $flags argument can be one of the following:
173 303
174 0 as above 304 0 as above
175 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 305 EV::RUN_ONCE block at most once (wait, but do not loop)
176 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 306 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
177 307
178=item EV::unloop [$how] 308=item EV::break [$how]
179 309
180=item $loop->unloop ([$how]) 310=item $loop->break ([$how])
181 311
182When called with no arguments or an argument of EV::UNLOOP_ONE, makes the 312When called with no arguments or an argument of EV::BREAK_ONE, makes the
183innermost call to EV::loop return. 313innermost call to EV::loop return.
184 314
185When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as 315When called with an argument of EV::BREAK_ALL, all calls to EV::loop will
186fast as possible. 316return as fast as possible.
187 317
188=item $count = EV::loop_count 318When called with an argument of EV::BREAK_CANCEL, any pending break will
319be cancelled.
189 320
321=item $count = EV::iteration
322
190=item $count = $loop->loop_count 323=item $count = $loop->iteration
191 324
192Return the number of times the event loop has polled for new 325Return the number of times the event loop has polled for new
193events. Sometiems useful as a generation counter. 326events. Sometimes useful as a generation counter.
194 327
195=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 328=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
196 329
197=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 330=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
198 331
… …
208If timeout is C<undef> or negative, then there will be no 341If timeout is C<undef> or negative, then there will be no
209timeout. Otherwise a EV::timer with this value will be started. 342timeout. Otherwise a EV::timer with this value will be started.
210 343
211When an error occurs or either the timeout or I/O watcher triggers, then 344When 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 345the 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>, 346you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
214C<EV::WRITE> and C<EV::TIMEOUT>). 347C<EV::WRITE> and C<EV::TIMER>).
215 348
216EV::once doesn't return anything: the watchers stay active till either 349EV::once doesn't return anything: the watchers stay active till either
217of them triggers, then they will be stopped and freed, and the callback 350of them triggers, then they will be stopped and freed, and the callback
218invoked. 351invoked.
219 352
220=item EV::feed_fd_event ($fd, $revents) 353=item EV::feed_fd_event $fd, $revents
221 354
222=item $loop->feed_fd_event ($fd, $revents) 355=item $loop->feed_fd_event ($fd, $revents)
223 356
224Feed an event on a file descriptor into EV. EV will react to this call as 357Feed an event on a file descriptor into EV. EV will react to this call as
225if the readyness notifications specified by C<$revents> (a combination of 358if the readyness notifications specified by C<$revents> (a combination of
226C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. 359C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
227 360
228=item EV::feed_signal_event ($signal) 361=item EV::feed_signal_event $signal
229 362
230Feed a signal event into EV. EV will react to this call as if the signal 363Feed a signal event into the default loop. EV will react to this call as
231specified by C<$signal> had occured. 364if the signal specified by C<$signal> had occured.
365
366=item EV::feed_signal $signal
367
368Feed a signal event into EV - unlike C<EV::feed_signal_event>, this works
369regardless of which loop has registered the signal, and is mainly useful
370fro custom signal implementations.
371
372=item EV::set_io_collect_interval $time
373
374=item $loop->set_io_collect_interval ($time)
375
376=item EV::set_timeout_collect_interval $time
377
378=item $loop->set_timeout_collect_interval ($time)
379
380These advanced functions set the minimum block interval when polling for I/O events and the minimum
381wait interval for timer events. See the libev documentation at
382L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
383(locally installed as F<EV::libev>) for a more detailed discussion.
384
385=item $count = EV::pending_count
386
387=item $count = $loop->pending_count
388
389Returns the number of currently pending watchers.
390
391=item EV::invoke_pending
392
393=item $loop->invoke_pending
394
395Invoke all currently pending watchers.
232 396
233=back 397=back
234 398
235 399
236=head1 WATCHER OBJECTS 400=head1 WATCHER OBJECTS
237 401
238A watcher is an object that gets created to record your interest in some 402A 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 403event. For instance, if you want to wait for STDIN to become readable, you
240would create an EV::io watcher for that: 404would create an EV::io watcher for that:
241 405
242 my $watcher = EV::io *STDIN, EV::READ, sub { 406 my $watcher = EV::io *STDIN, EV::READ, sub {
243 my ($watcher, $revents) = @_; 407 my ($watcher, $revents) = @_;
244 warn "yeah, STDIN should not be readable without blocking!\n" 408 warn "yeah, STDIN should now be readable without blocking!\n"
245 }; 409 };
246 410
247All watchers can be active (waiting for events) or inactive (paused). Only 411All watchers can be active (waiting for events) or inactive (paused). Only
248active watchers will have their callbacks invoked. All callbacks will be 412active watchers will have their callbacks invoked. All callbacks will be
249called with at least two arguments: the watcher and a bitmask of received 413called with at least two arguments: the watcher and a bitmask of received
250events. 414events.
251 415
252Each watcher type has its associated bit in revents, so you can use the 416Each 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 417same callback for multiple watchers. The event mask is named after the
254type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 418type, 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 419EV::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 420(which can set both EV::READ and EV::WRITE bits).
257uses EV::TIMEOUT).
258 421
259In the rare case where one wants to create a watcher but not start it at 422In 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 423the 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. 424its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
262 425
… …
333Feed some events on this watcher into EV. EV will react to this call as if 496Feed some events on this watcher into EV. EV will react to this call as if
334the watcher had received the given C<$revents> mask. 497the watcher had received the given C<$revents> mask.
335 498
336=item $revents = $w->clear_pending 499=item $revents = $w->clear_pending
337 500
338If the watcher is pending, this function returns clears its pending status 501If the watcher is pending, this function clears its pending status and
339and returns its C<$revents> bitset (as if its callback was invoked). If the 502returns its C<$revents> bitset (as if its callback was invoked). If the
340watcher isn't pending it does nothing and returns C<0>. 503watcher isn't pending it does nothing and returns C<0>.
341 504
342=item $previous_state = $w->keepalive ($bool) 505=item $previous_state = $w->keepalive ($bool)
343 506
344Normally, C<EV::loop> will return when there are no active watchers 507Normally, 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 508(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), 509convenient 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 510call 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 :). 511finished (or they forgot to register some watchers for their task :).
349 512
350Sometimes, however, this gets in your way, for example when you the module 513Sometimes, 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 514that 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 515as a long-living watcher (for example a DNS client module written by
353somebody else even). Then you might want any outstanding requests to be 516somebody 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 517handled, but you would not want to keep C<EV::loop> from returning just
355because you happen to have this long-running UDP port watcher. 518because you happen to have this long-running UDP port watcher.
356 519
357In this case you can clear the keepalive status, which means that even 520In 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. 521though your watcher is active, it won't keep C<EV::loop> from returning.
359 522
360The initial value for keepalive is true (enabled), and you cna change it 523The initial value for keepalive is true (enabled), and you can change it
361any time. 524any time.
362 525
363Example: Register an I/O watcher for some UDP socket but do not keep the 526Example: Register an I/O watcher for some UDP socket but do not keep the
364event loop from running just because of that watcher. 527event loop from running just because of that watcher.
365 528
366 my $udp_socket = ... 529 my $udp_socket = ...
367 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 530 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
368 $udp_watcher->keepalive (0); 531 $udp_watcher->keepalive (0);
369 532
533=item $loop = $w->loop
534
535Return the loop that this watcher is attached to.
536
370=back 537=back
371 538
372 539
373=head1 WATCHER TYPES 540=head1 WATCHER TYPES
374 541
… …
380 547
381=item $w = EV::io $fileno_or_fh, $eventmask, $callback 548=item $w = EV::io $fileno_or_fh, $eventmask, $callback
382 549
383=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 550=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
384 551
385=item $w = $loop->io 8$fileno_or_fh, $eventmask, $callback) 552=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
386 553
387=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback) 554=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
388 555
389As long as the returned watcher object is alive, call the C<$callback> 556As long as the returned watcher object is alive, call the C<$callback>
390when at least one of events specified in C<$eventmask> occurs. 557when 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 665This time simply fires at the wallclock time C<$at> and doesn't repeat. It
499will not adjust when a time jump occurs, that is, if it is to be run 666will not adjust when a time jump occurs, that is, if it is to be run
500at January 1st 2011 then it will run when the system time reaches or 667at January 1st 2011 then it will run when the system time reaches or
501surpasses this time. 668surpasses this time.
502 669
503=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 670=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
504 671
505In this mode the watcher will always be scheduled to time out at the 672In this mode the watcher will always be scheduled to time out at the
506next C<$at + N * $interval> time (for some integer N) and then repeat, 673next C<$at + N * $interval> time (for some integer N) and then repeat,
507regardless of any time jumps. 674regardless of any time jumps.
508 675
… …
526time the periodic watcher gets scheduled, the reschedule callback 693time the periodic watcher gets scheduled, the reschedule callback
527($reschedule_cb) will be called with the watcher as first, and the current 694($reschedule_cb) will be called with the watcher as first, and the current
528time as second argument. 695time as second argument.
529 696
530I<This callback MUST NOT stop or destroy this or any other periodic 697I<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 698watcher, ever, and MUST NOT call any event loop functions or methods>. If
532afterwards. 699you need to stop it, return 1e30 and stop it afterwards. You may create
700and start a C<EV::prepare> watcher for this task.
533 701
534It must return the next time to trigger, based on the passed time value 702It 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 703(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 704argument). It will usually be called just before the callback will be
537might be called at other times, too. 705triggered, but might be called at other times, too.
538 706
539This can be used to create very complex timers, such as a timer that 707This 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 708triggers 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 709midnight, 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 710in about the same space (without requiring elaborate modules), drop me a
… …
578 746
579=item $w = EV::signal $signal, $callback 747=item $w = EV::signal $signal, $callback
580 748
581=item $w = EV::signal_ns $signal, $callback 749=item $w = EV::signal_ns $signal, $callback
582 750
751=item $w = $loop->signal ($signal, $callback)
752
753=item $w = $loop->signal_ns ($signal, $callback)
754
583Call the callback when $signal is received (the signal can be specified by 755Call the callback when $signal is received (the signal can be specified by
584number or by name, just as with C<kill> or C<%SIG>). 756number or by name, just as with C<kill> or C<%SIG>).
757
758Only one event loop can grab a given signal - attempting to grab the same
759signal from two EV loops will crash the program immediately or cause data
760corruption.
585 761
586EV will grab the signal for the process (the kernel only allows one 762EV 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, 763component 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 764and removes it again when you stop it. Perl does the same when you
589add/remove callbacks to C<%SIG>, so watch out. 765add/remove callbacks to C<%SIG>, so watch out.
… …
609 785
610=head3 CHILD WATCHERS - watch out for process status changes 786=head3 CHILD WATCHERS - watch out for process status changes
611 787
612=over 4 788=over 4
613 789
614=item $w = EV::child $pid, $callback 790=item $w = EV::child $pid, $trace, $callback
615 791
616=item $w = EV::child_ns $pid, $callback 792=item $w = EV::child_ns $pid, $trace, $callback
617 793
618=item $w = $loop->child ($pid, $callback) 794=item $w = $loop->child ($pid, $trace, $callback)
619 795
620=item $w = $loop->child_ns ($pid, $callback) 796=item $w = $loop->child_ns ($pid, $trace, $callback)
621 797
622Call the callback when a status change for pid C<$pid> (or any pid if 798Call 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 799if C<$pid> is 0) has been received (a status change happens when the
800process terminates or is killed, or, when trace is true, additionally when
801it is stopped or continued). More precisely: when the process receives
624a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all 802a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
625changed/zombie children and call the callback. 803changed/zombie children and call the callback.
626 804
627It is valid (and fully supported) to install a child watcher after a child 805It 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 806has 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 813You can have as many pid watchers per pid as you want, they will all be
636called. 814called.
637 815
638The C<child_ns> variant doesn't start (activate) the newly created watcher. 816The C<child_ns> variant doesn't start (activate) the newly created watcher.
639 817
640=item $w->set ($pid) 818=item $w->set ($pid, $trace)
641 819
642Reconfigures the watcher, see the constructor above for details. Can be called at 820Reconfigures the watcher, see the constructor above for details. Can be called at
643any time. 821any time.
644 822
645=item $current_pid = $w->pid 823=item $current_pid = $w->pid
646
647=item $old_pid = $w->pid ($new_pid)
648 824
649Returns the previously set process id and optionally set a new one. 825Returns the previously set process id and optionally set a new one.
650 826
651=item $exit_status = $w->rstatus 827=item $exit_status = $w->rstatus
652 828
… …
787 963
788=item $w = EV::prepare_ns $callback 964=item $w = EV::prepare_ns $callback
789 965
790=item $w = $loop->prepare ($callback) 966=item $w = $loop->prepare ($callback)
791 967
792=item $w = $loop->prepare_ns 8$callback) 968=item $w = $loop->prepare_ns ($callback)
793 969
794Call the callback just before the process would block. You can still 970Call the callback just before the process would block. You can still
795create/modify any watchers at this point. 971create/modify any watchers at this point.
796 972
797See the EV::check watcher, below, for explanations and an example. 973See the EV::check watcher, below, for explanations and an example.
… …
814=item $w = $loop->check_ns ($callback) 990=item $w = $loop->check_ns ($callback)
815 991
816Call the callback just after the process wakes up again (after it has 992Call the callback just after the process wakes up again (after it has
817gathered events), but before any other callbacks have been invoked. 993gathered events), but before any other callbacks have been invoked.
818 994
819This is used to integrate other event-based software into the EV 995This 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 996mainloop: 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 997timer watchers as required by the other software. Here is a real-world
822example of integrating Net::SNMP (with some details left out): 998example of integrating Net::SNMP (with some details left out):
823 999
824 our @snmp_watcher; 1000 our @snmp_watcher;
… …
854 # make the dispatcher handle any new stuff 1030 # make the dispatcher handle any new stuff
855 ... not shown 1031 ... not shown
856 }; 1032 };
857 1033
858The callbacks of the created watchers will not be called as the watchers 1034The callbacks of the created watchers will not be called as the watchers
859are destroyed before this cna happen (remember EV::check gets called 1035are destroyed before this can happen (remember EV::check gets called
860first). 1036first).
861 1037
862The C<check_ns> variant doesn't start (activate) the newly created watcher. 1038The C<check_ns> variant doesn't start (activate) the newly created watcher.
1039
1040=item EV::CHECK constant issues
1041
1042Like all other watcher types, there is a bitmask constant for use in
1043C<$revents> and other places. The C<EV::CHECK> is special as it has
1044the same name as the C<CHECK> sub called by Perl. This doesn't cause
1045big issues on newer perls (beginning with 5.8.9), but it means thatthe
1046constant must be I<inlined>, i.e. runtime calls will not work. That means
1047that as long as you always C<use EV> and then C<EV::CHECK> you are on the
1048safe side.
863 1049
864=back 1050=back
865 1051
866 1052
867=head3 FORK WATCHERS - the audacity to resume the event loop after a fork 1053=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
… …
882 1068
883Call the callback before the event loop is resumed in the child process 1069Call the callback before the event loop is resumed in the child process
884after a fork. 1070after a fork.
885 1071
886The C<fork_ns> variant doesn't start (activate) the newly created watcher. 1072The C<fork_ns> variant doesn't start (activate) the newly created watcher.
1073
1074=back
1075
1076
1077=head3 EMBED WATCHERS - when one backend isn't enough...
1078
1079This is a rather advanced watcher type that lets you embed one event loop
1080into another (currently only IO events are supported in the embedded
1081loop, other types of watchers might be handled in a delayed or incorrect
1082fashion and must not be used).
1083
1084See the libev documentation at
1085L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
1086(locally installed as F<EV::libev>) for more details.
1087
1088In short, this watcher is most useful on BSD systems without working
1089kqueue to still be able to handle a large number of sockets:
1090
1091 my $socket_loop;
1092
1093 # check wether we use SELECT or POLL _and_ KQUEUE is supported
1094 if (
1095 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
1096 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
1097 ) {
1098 # use kqueue for sockets
1099 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
1100 }
1101
1102 # use the default loop otherwise
1103 $socket_loop ||= EV::default_loop;
1104
1105=over 4
1106
1107=item $w = EV::embed $otherloop[, $callback]
1108
1109=item $w = EV::embed_ns $otherloop[, $callback]
1110
1111=item $w = $loop->embed ($otherloop[, $callback])
1112
1113=item $w = $loop->embed_ns ($otherloop[, $callback])
1114
1115Call the callback when the embedded event loop (C<$otherloop>) has any
1116I/O activity. The C<$callback> is optional: if it is missing, then the
1117embedded event loop will be managed automatically (which is recommended),
1118otherwise you have to invoke C<sweep> yourself.
1119
1120The C<embed_ns> variant doesn't start (activate) the newly created watcher.
1121
1122=back
1123
1124=head3 ASYNC WATCHERS - how to wake up another event loop
1125
1126Async watchers are provided by EV, but have little use in perl directly,
1127as perl neither supports threads running in parallel nor direct access to
1128signal handlers or other contexts where they could be of value.
1129
1130It is, however, possible to use them from the XS level.
1131
1132Please see the libev documentation for further details.
1133
1134=over 4
1135
1136=item $w = EV::async $callback
1137
1138=item $w = EV::async_ns $callback
1139
1140=item $w->send
1141
1142=item $bool = $w->async_pending
887 1143
888=back 1144=back
889 1145
890 1146
891=head1 PERL SIGNALS 1147=head1 PERL SIGNALS
… …
902to be called on every event loop iteration by installing a C<EV::check> 1158to be called on every event loop iteration by installing a C<EV::check>
903watcher: 1159watcher:
904 1160
905 my $async_check = EV::check sub { }; 1161 my $async_check = EV::check sub { };
906 1162
907This ensures that perl shortly gets into control for a short time, and 1163This ensures that perl gets into control for a short time to handle any
908also ensures slower overall operation. 1164pending signals, and also ensures (slightly) slower overall operation.
909 1165
910=head1 THREADS 1166=head1 ITHREADS
911 1167
912Threads are not supported by this module in any way. Perl pseudo-threads 1168Ithreads 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 1169is evil stuff and must die. Real threads as provided by Coro are fully
914on thread support for it. 1170supported (and enhanced support is available via L<Coro::EV>).
915 1171
916=head1 FORK 1172=head1 FORK
917 1173
918Most of the "improved" event delivering mechanisms of modern operating 1174Most of the "improved" event delivering mechanisms of modern operating
919systems have quite a few problems with fork(2) (to put it bluntly: it is 1175systems have quite a few problems with fork(2) (to put it bluntly: it is
… …
941 1197
9421; 11981;
943 1199
944=head1 SEE ALSO 1200=head1 SEE ALSO
945 1201
1202L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS>
946L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as 1203(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 1204loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient thread
948coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP). 1205integration), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1206event-loop agnostic and portable event driven programming.
949 1207
950=head1 AUTHOR 1208=head1 AUTHOR
951 1209
952 Marc Lehmann <schmorp@schmorp.de> 1210 Marc Lehmann <schmorp@schmorp.de>
953 http://home.schmorp.de/ 1211 http://home.schmorp.de/
954 1212
955=cut 1213=cut
956 1214

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