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Revision 1.72 by root, Thu Dec 20 07:12:57 2007 UTC vs.
Revision 1.132 by root, Thu Dec 30 07:28:47 2010 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::loop; # 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::loop EV::LOOP_ONESHOT; # 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::loop EV::LOOP_NONBLOCK; # 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 = '4.02';
74 use XSLoader; 125 use XSLoader;
75 XSLoader::load "EV", $VERSION; 126 XSLoader::load "EV", $VERSION;
76} 127}
77 128
78@EV::IO::ISA = 129@EV::IO::ISA =
… …
84@EV::Idle::ISA = 135@EV::Idle::ISA =
85@EV::Prepare::ISA = 136@EV::Prepare::ISA =
86@EV::Check::ISA = 137@EV::Check::ISA =
87@EV::Embed::ISA = 138@EV::Embed::ISA =
88@EV::Fork::ISA = 139@EV::Fork::ISA =
140@EV::Async::ISA =
89 "EV::Watcher"; 141 "EV::Watcher";
90 142
91@EV::Loop::Default::ISA = "EV::Loop"; 143@EV::Loop::Default::ISA = "EV::Loop";
144
145=head1 EVENT LOOPS
146
147EV supports multiple event loops: There is a single "default event loop"
148that can handle everything including signals and child watchers, and any
149number of "dynamic event loops" that can use different backends (with
150various limitations), but no child and signal watchers.
151
152You do not have to do anything to create the default event loop: When
153the module is loaded a suitable backend is selected on the premise of
154selecting a working backend (which for example rules out kqueue on most
155BSDs). Modules should, unless they have "special needs" always use the
156default loop as this is fastest (perl-wise), best supported by other
157modules (e.g. AnyEvent or Coro) and most portable event loop.
158
159For specific programs you can create additional event loops dynamically.
160
161If you want to take advantage of kqueue (which often works properly for
162sockets only) even though the default loop doesn't enable it, you can
163I<embed> a kqueue loop into the default loop: running the default loop
164will then also service the kqueue loop to some extent. See the example in
165the section about embed watchers for an example on how to achieve that.
166
167=over 4
168
169=item $loop = new EV::Loop [$flags]
170
171Create a new event loop as per the specified flags. Please refer to
172the C<ev_loop_new ()> function description in the libev documentation
173(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
174or locally-installed as F<EV::libev> manpage) for more info.
175
176The loop will automatically be destroyed when it is no longer referenced
177by any watcher and the loop object goes out of scope.
178
179If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
180is recommended, as only the default event loop is protected by this
181module. If you I<are> embedding this loop in the default loop, this is not
182necessary, as C<EV::embed> automatically does the right thing on fork.
183
184=item $loop->loop_fork
185
186Must be called after a fork in the child, before entering or continuing
187the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
188this function automatically, at some performance loss (refer to the libev
189documentation).
190
191=item $loop->loop_verify
192
193Calls C<ev_verify> to make internal consistency checks (for debugging
194libev) and abort the program if any data structures were found to be
195corrupted.
196
197=item $loop = EV::default_loop [$flags]
198
199Return the default loop (which is a singleton object). Since this module
200already creates the default loop with default flags, specifying flags here
201will not have any effect unless you destroy the default loop first, which
202isn't supported. So in short: don't do it, and if you break it, you get to
203keep the pieces.
204
205=back
206
92 207
93=head1 BASIC INTERFACE 208=head1 BASIC INTERFACE
94 209
95=over 4 210=over 4
96 211
… …
100throws an exception (with $@ containing the error). The default prints an 215throws an exception (with $@ containing the error). The default prints an
101informative message and continues. 216informative message and continues.
102 217
103If this callback throws an exception it will be silently ignored. 218If this callback throws an exception it will be silently ignored.
104 219
220=item $flags = EV::supported_backends
221
222=item $flags = EV::recommended_backends
223
224=item $flags = EV::embeddable_backends
225
226Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
227instance of EV, the set of recommended backends (supposed to be good) for
228this platform and the set of embeddable backends (see EMBED WATCHERS).
229
230=item EV::sleep $seconds
231
232Block the process for the given number of (fractional) seconds.
233
105=item $time = EV::time 234=item $time = EV::time
106 235
107Returns the current time in (fractional) seconds since the epoch. 236Returns the current time in (fractional) seconds since the epoch.
108 237
109=item $time = EV::now 238=item $time = EV::now
110 239
240=item $time = $loop->now
241
111Returns the time the last event loop iteration has been started. This 242Returns the time the last event loop iteration has been started. This
112is the time that (relative) timers are based on, and refering to it is 243is the time that (relative) timers are based on, and referring to it is
113usually faster then calling EV::time. 244usually faster then calling EV::time.
114 245
115=item $method = EV::method 246=item EV::now_update
116 247
248=item $loop->now_update
249
250Establishes the current time by querying the kernel, updating the time
251returned by C<EV::now> in the progress. This is a costly operation and
252is usually done automatically within C<EV::loop>.
253
254This function is rarely useful, but when some event callback runs for a
255very long time without entering the event loop, updating libev's idea of
256the current time is a good idea.
257
258=item EV::suspend
259
260=item $loop->suspend
261
262=item EV::resume
263
264=item $loop->resume
265
266These two functions suspend and resume a loop, for use when the loop is
267not used for a while and timeouts should not be processed.
268
269A typical use case would be an interactive program such as a game: When
270the user presses C<^Z> to suspend the game and resumes it an hour later it
271would be best to handle timeouts as if no time had actually passed while
272the program was suspended. This can be achieved by calling C<suspend>
273in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
274C<resume> directly afterwards to resume timer processing.
275
276Effectively, all C<timer> watchers will be delayed by the time spend
277between C<suspend> and C<resume>, and all C<periodic> watchers
278will be rescheduled (that is, they will lose any events that would have
279occured while suspended).
280
281After calling C<suspend> you B<must not> call I<any> function on the given
282loop other than C<resume>, and you B<must not> call C<resume>
283without a previous call to C<suspend>.
284
285Calling C<suspend>/C<resume> has the side effect of updating the event
286loop time (see C<now_update>).
287
288=item $backend = EV::backend
289
290=item $backend = $loop->backend
291
117Returns an integer describing the backend used by libev (EV::METHOD_SELECT 292Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
118or EV::METHOD_EPOLL). 293or EV::BACKEND_EPOLL).
119 294
120=item EV::loop [$flags] 295=item EV::loop [$flags]
296
297=item $loop->loop ([$flags])
121 298
122Begin checking for events and calling callbacks. It returns when a 299Begin checking for events and calling callbacks. It returns when a
123callback calls EV::unloop. 300callback calls EV::unloop.
124 301
125The $flags argument can be one of the following: 302The $flags argument can be one of the following:
… …
128 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 305 EV::LOOP_ONESHOT block at most once (wait, but do not loop)
129 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 306 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
130 307
131=item EV::unloop [$how] 308=item EV::unloop [$how]
132 309
310=item $loop->unloop ([$how])
311
133When called with no arguments or an argument of EV::UNLOOP_ONE, makes the 312When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
134innermost call to EV::loop return. 313innermost call to EV::loop return.
135 314
136When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as 315When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
137fast as possible. 316fast as possible.
138 317
139=item $count = EV::loop_count 318=item $count = EV::loop_count
140 319
320=item $count = $loop->loop_count
321
141Return the number of times the event loop has polled for new 322Return the number of times the event loop has polled for new
142events. Sometiems useful as a generation counter. 323events. Sometimes useful as a generation counter.
143 324
144=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 325=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
326
327=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
145 328
146This function rolls together an I/O and a timer watcher for a single 329This function rolls together an I/O and a timer watcher for a single
147one-shot event without the need for managing a watcher object. 330one-shot event without the need for managing a watcher object.
148 331
149If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> 332If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
… …
155If timeout is C<undef> or negative, then there will be no 338If timeout is C<undef> or negative, then there will be no
156timeout. Otherwise a EV::timer with this value will be started. 339timeout. Otherwise a EV::timer with this value will be started.
157 340
158When an error occurs or either the timeout or I/O watcher triggers, then 341When an error occurs or either the timeout or I/O watcher triggers, then
159the callback will be called with the received event set (in general 342the callback will be called with the received event set (in general
160you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>, 343you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
161C<EV::WRITE> and C<EV::TIMEOUT>). 344C<EV::WRITE> and C<EV::TIMER>).
162 345
163EV::once doesn't return anything: the watchers stay active till either 346EV::once doesn't return anything: the watchers stay active till either
164of them triggers, then they will be stopped and freed, and the callback 347of them triggers, then they will be stopped and freed, and the callback
165invoked. 348invoked.
166 349
167=item EV::feed_fd_event ($fd, $revents) 350=item EV::feed_fd_event ($fd, $revents)
168 351
352=item $loop->feed_fd_event ($fd, $revents)
353
169Feed an event on a file descriptor into EV. EV will react to this call as 354Feed an event on a file descriptor into EV. EV will react to this call as
170if the readyness notifications specified by C<$revents> (a combination of 355if the readyness notifications specified by C<$revents> (a combination of
171C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. 356C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
172 357
173=item EV::feed_signal_event ($signal) 358=item EV::feed_signal_event ($signal)
174 359
175Feed a signal event into EV. EV will react to this call as if the signal 360Feed a signal event into EV. EV will react to this call as if the signal
176specified by C<$signal> had occured. 361specified by C<$signal> had occured.
177 362
178=back 363=item EV::set_io_collect_interval $time
179 364
365=item $loop->set_io_collect_interval ($time)
180 366
367=item EV::set_timeout_collect_interval $time
368
369=item $loop->set_timeout_collect_interval ($time)
370
371These advanced functions set the minimum block interval when polling for I/O events and the minimum
372wait interval for timer events. See the libev documentation at
373L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
374(locally installed as F<EV::libev>) for a more detailed discussion.
375
376=item $count = EV::pending_count
377
378=item $count = $loop->pending_count
379
380Returns the number of currently pending watchers.
381
382=item EV::invoke_pending
383
384=item $loop->invoke_pending
385
386Invoke all currently pending watchers.
387
388=back
389
390
181=head2 WATCHER OBJECTS 391=head1 WATCHER OBJECTS
182 392
183A watcher is an object that gets created to record your interest in some 393A watcher is an object that gets created to record your interest in some
184event. For instance, if you want to wait for STDIN to become readable, you 394event. For instance, if you want to wait for STDIN to become readable, you
185would create an EV::io watcher for that: 395would create an EV::io watcher for that:
186 396
187 my $watcher = EV::io *STDIN, EV::READ, sub { 397 my $watcher = EV::io *STDIN, EV::READ, sub {
188 my ($watcher, $revents) = @_; 398 my ($watcher, $revents) = @_;
189 warn "yeah, STDIN should not be readable without blocking!\n" 399 warn "yeah, STDIN should now be readable without blocking!\n"
190 }; 400 };
191 401
192All watchers can be active (waiting for events) or inactive (paused). Only 402All watchers can be active (waiting for events) or inactive (paused). Only
193active watchers will have their callbacks invoked. All callbacks will be 403active watchers will have their callbacks invoked. All callbacks will be
194called with at least two arguments: the watcher and a bitmask of received 404called with at least two arguments: the watcher and a bitmask of received
195events. 405events.
196 406
197Each watcher type has its associated bit in revents, so you can use the 407Each watcher type has its associated bit in revents, so you can use the
198same callback for multiple watchers. The event mask is named after the 408same callback for multiple watchers. The event mask is named after the
199type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 409type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
200EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events 410EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
201(which can set both EV::READ and EV::WRITE bits), and EV::timer (which 411(which can set both EV::READ and EV::WRITE bits).
202uses EV::TIMEOUT).
203 412
204In the rare case where one wants to create a watcher but not start it at 413In the rare case where one wants to create a watcher but not start it at
205the same time, each constructor has a variant with a trailing C<_ns> in 414the same time, each constructor has a variant with a trailing C<_ns> in
206its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. 415its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
207 416
… …
278Feed some events on this watcher into EV. EV will react to this call as if 487Feed some events on this watcher into EV. EV will react to this call as if
279the watcher had received the given C<$revents> mask. 488the watcher had received the given C<$revents> mask.
280 489
281=item $revents = $w->clear_pending 490=item $revents = $w->clear_pending
282 491
283If the watcher is pending, this function returns clears its pending status 492If the watcher is pending, this function clears its pending status and
284and returns its C<$revents> bitset (as if its callback was invoked). If the 493returns its C<$revents> bitset (as if its callback was invoked). If the
285watcher isn't pending it does nothing and returns C<0>. 494watcher isn't pending it does nothing and returns C<0>.
286 495
287=item $previous_state = $w->keepalive ($bool) 496=item $previous_state = $w->keepalive ($bool)
288 497
289Normally, C<EV::loop> will return when there are no active watchers 498Normally, C<EV::loop> will return when there are no active watchers
290(which is a "deadlock" because no progress can be made anymore). This is 499(which is a "deadlock" because no progress can be made anymore). This is
291convinient because it allows you to start your watchers (and your jobs), 500convenient because it allows you to start your watchers (and your jobs),
292call C<EV::loop> once and when it returns you know that all your jobs are 501call C<EV::loop> once and when it returns you know that all your jobs are
293finished (or they forgot to register some watchers for their task :). 502finished (or they forgot to register some watchers for their task :).
294 503
295Sometimes, however, this gets in your way, for example when you the module 504Sometimes, however, this gets in your way, for example when the module
296that calls C<EV::loop> (usually the main program) is not the same module 505that calls C<EV::loop> (usually the main program) is not the same module
297as a long-living watcher (for example a DNS client module written by 506as a long-living watcher (for example a DNS client module written by
298somebody else even). Then you might want any outstanding requests to be 507somebody else even). Then you might want any outstanding requests to be
299handled, but you would not want to keep C<EV::loop> from returning just 508handled, but you would not want to keep C<EV::loop> from returning just
300because you happen to have this long-running UDP port watcher. 509because you happen to have this long-running UDP port watcher.
301 510
302In this case you can clear the keepalive status, which means that even 511In this case you can clear the keepalive status, which means that even
303though your watcher is active, it won't keep C<EV::loop> from returning. 512though your watcher is active, it won't keep C<EV::loop> from returning.
304 513
305The initial value for keepalive is true (enabled), and you cna change it 514The initial value for keepalive is true (enabled), and you can change it
306any time. 515any time.
307 516
308Example: Register an I/O watcher for some UDP socket but do not keep the 517Example: Register an I/O watcher for some UDP socket but do not keep the
309event loop from running just because of that watcher. 518event loop from running just because of that watcher.
310 519
311 my $udp_socket = ... 520 my $udp_socket = ...
312 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 521 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
313 $udp_watcher->keepalive (0); 522 $udp_watcher->keepalive (0);
314 523
315=back 524=item $loop = $w->loop
316 525
526Return the loop that this watcher is attached to.
317 527
528=back
529
530
318=head2 WATCHER TYPES 531=head1 WATCHER TYPES
319 532
320Each of the following subsections describes a single watcher type. 533Each of the following subsections describes a single watcher type.
321 534
322=head3 I/O WATCHERS - is this file descriptor readable or writable? 535=head3 I/O WATCHERS - is this file descriptor readable or writable?
323 536
324=over 4 537=over 4
325 538
326=item $w = EV::io $fileno_or_fh, $eventmask, $callback 539=item $w = EV::io $fileno_or_fh, $eventmask, $callback
327 540
328=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 541=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
542
543=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
544
545=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
329 546
330As long as the returned watcher object is alive, call the C<$callback> 547As long as the returned watcher object is alive, call the C<$callback>
331when at least one of events specified in C<$eventmask> occurs. 548when at least one of events specified in C<$eventmask> occurs.
332 549
333The $eventmask can be one or more of these constants ORed together: 550The $eventmask can be one or more of these constants ORed together:
… …
362=over 4 579=over 4
363 580
364=item $w = EV::timer $after, $repeat, $callback 581=item $w = EV::timer $after, $repeat, $callback
365 582
366=item $w = EV::timer_ns $after, $repeat, $callback 583=item $w = EV::timer_ns $after, $repeat, $callback
584
585=item $w = $loop->timer ($after, $repeat, $callback)
586
587=item $w = $loop->timer_ns ($after, $repeat, $callback)
367 588
368Calls the callback after C<$after> seconds (which may be fractional). If 589Calls the callback after C<$after> seconds (which may be fractional). If
369C<$repeat> is non-zero, the timer will be restarted (with the $repeat 590C<$repeat> is non-zero, the timer will be restarted (with the $repeat
370value as $after) after the callback returns. 591value as $after) after the callback returns.
371 592
… …
412=over 4 633=over 4
413 634
414=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback 635=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
415 636
416=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 637=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
638
639=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
640
641=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
417 642
418Similar to EV::timer, but is not based on relative timeouts but on 643Similar to EV::timer, but is not based on relative timeouts but on
419absolute times. Apart from creating "simple" timers that trigger "at" the 644absolute times. Apart from creating "simple" timers that trigger "at" the
420specified time, it can also be used for non-drifting absolute timers and 645specified time, it can also be used for non-drifting absolute timers and
421more complex, cron-like, setups that are not adversely affected by time 646more complex, cron-like, setups that are not adversely affected by time
… …
431This time simply fires at the wallclock time C<$at> and doesn't repeat. It 656This time simply fires at the wallclock time C<$at> and doesn't repeat. It
432will not adjust when a time jump occurs, that is, if it is to be run 657will not adjust when a time jump occurs, that is, if it is to be run
433at January 1st 2011 then it will run when the system time reaches or 658at January 1st 2011 then it will run when the system time reaches or
434surpasses this time. 659surpasses this time.
435 660
436=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 661=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
437 662
438In this mode the watcher will always be scheduled to time out at the 663In this mode the watcher will always be scheduled to time out at the
439next C<$at + N * $interval> time (for some integer N) and then repeat, 664next C<$at + N * $interval> time (for some integer N) and then repeat,
440regardless of any time jumps. 665regardless of any time jumps.
441 666
… …
459time the periodic watcher gets scheduled, the reschedule callback 684time the periodic watcher gets scheduled, the reschedule callback
460($reschedule_cb) will be called with the watcher as first, and the current 685($reschedule_cb) will be called with the watcher as first, and the current
461time as second argument. 686time as second argument.
462 687
463I<This callback MUST NOT stop or destroy this or any other periodic 688I<This callback MUST NOT stop or destroy this or any other periodic
464watcher, ever>. If you need to stop it, return 1e30 and stop it 689watcher, ever, and MUST NOT call any event loop functions or methods>. If
465afterwards. 690you need to stop it, return 1e30 and stop it afterwards. You may create
691and start a C<EV::prepare> watcher for this task.
466 692
467It must return the next time to trigger, based on the passed time value 693It must return the next time to trigger, based on the passed time value
468(that is, the lowest time value larger than to the second argument). It 694(that is, the lowest time value larger than or equal to to the second
469will usually be called just before the callback will be triggered, but 695argument). It will usually be called just before the callback will be
470might be called at other times, too. 696triggered, but might be called at other times, too.
471 697
472This can be used to create very complex timers, such as a timer that 698This can be used to create very complex timers, such as a timer that
473triggers on each midnight, local time (actually 24 hours after the last 699triggers on each midnight, local time (actually 24 hours after the last
474midnight, to keep the example simple. If you know a way to do it correctly 700midnight, to keep the example simple. If you know a way to do it correctly
475in about the same space (without requiring elaborate modules), drop me a 701in about the same space (without requiring elaborate modules), drop me a
… …
511 737
512=item $w = EV::signal $signal, $callback 738=item $w = EV::signal $signal, $callback
513 739
514=item $w = EV::signal_ns $signal, $callback 740=item $w = EV::signal_ns $signal, $callback
515 741
742=item $w = $loop->signal ($signal, $callback)
743
744=item $w = $loop->signal_ns ($signal, $callback)
745
516Call the callback when $signal is received (the signal can be specified by 746Call the callback when $signal is received (the signal can be specified by
517number or by name, just as with C<kill> or C<%SIG>). 747number or by name, just as with C<kill> or C<%SIG>).
748
749Only one event loop can grab a given signal - attempting to grab the same
750signal from two EV loops will crash the program immediately or cause data
751corruption.
518 752
519EV will grab the signal for the process (the kernel only allows one 753EV will grab the signal for the process (the kernel only allows one
520component to receive a signal at a time) when you start a signal watcher, 754component to receive a signal at a time) when you start a signal watcher,
521and removes it again when you stop it. Perl does the same when you 755and removes it again when you stop it. Perl does the same when you
522add/remove callbacks to C<%SIG>, so watch out. 756add/remove callbacks to C<%SIG>, so watch out.
… …
542 776
543=head3 CHILD WATCHERS - watch out for process status changes 777=head3 CHILD WATCHERS - watch out for process status changes
544 778
545=over 4 779=over 4
546 780
547=item $w = EV::child $pid, $callback 781=item $w = EV::child $pid, $trace, $callback
548 782
549=item $w = EV::child_ns $pid, $callback 783=item $w = EV::child_ns $pid, $trace, $callback
550 784
785=item $w = $loop->child ($pid, $trace, $callback)
786
787=item $w = $loop->child_ns ($pid, $trace, $callback)
788
551Call the callback when a status change for pid C<$pid> (or any pid if 789Call the callback when a status change for pid C<$pid> (or any pid
552C<$pid> is 0) has been received. More precisely: when the process receives 790if C<$pid> is 0) has been received (a status change happens when the
791process terminates or is killed, or, when trace is true, additionally when
792it is stopped or continued). More precisely: when the process receives
553a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all 793a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
554changed/zombie children and call the callback. 794changed/zombie children and call the callback.
555 795
556It is valid (and fully supported) to install a child watcher after a child 796It is valid (and fully supported) to install a child watcher after a child
557has exited but before the event loop has started its next iteration (for 797has exited but before the event loop has started its next iteration (for
… …
564You can have as many pid watchers per pid as you want, they will all be 804You can have as many pid watchers per pid as you want, they will all be
565called. 805called.
566 806
567The C<child_ns> variant doesn't start (activate) the newly created watcher. 807The C<child_ns> variant doesn't start (activate) the newly created watcher.
568 808
569=item $w->set ($pid) 809=item $w->set ($pid, $trace)
570 810
571Reconfigures the watcher, see the constructor above for details. Can be called at 811Reconfigures the watcher, see the constructor above for details. Can be called at
572any time. 812any time.
573 813
574=item $current_pid = $w->pid 814=item $current_pid = $w->pid
575 815
576=item $old_pid = $w->pid ($new_pid)
577
578Returns the previously set process id and optionally set a new one. 816Returns the previously set process id and optionally set a new one.
579 817
580=item $exit_status = $w->rstatus 818=item $exit_status = $w->rstatus
581 819
582Return the exit/wait status (as returned by waitpid, see the waitpid entry 820Return the exit/wait status (as returned by waitpid, see the waitpid entry
… …
595=over 4 833=over 4
596 834
597=item $w = EV::stat $path, $interval, $callback 835=item $w = EV::stat $path, $interval, $callback
598 836
599=item $w = EV::stat_ns $path, $interval, $callback 837=item $w = EV::stat_ns $path, $interval, $callback
838
839=item $w = $loop->stat ($path, $interval, $callback)
840
841=item $w = $loop->stat_ns ($path, $interval, $callback)
600 842
601Call the callback when a file status change has been detected on 843Call the callback when a file status change has been detected on
602C<$path>. The C<$path> does not need to exist, changing from "path exists" 844C<$path>. The C<$path> does not need to exist, changing from "path exists"
603to "path does not exist" is a status change like any other. 845to "path does not exist" is a status change like any other.
604 846
… …
674=over 4 916=over 4
675 917
676=item $w = EV::idle $callback 918=item $w = EV::idle $callback
677 919
678=item $w = EV::idle_ns $callback 920=item $w = EV::idle_ns $callback
921
922=item $w = $loop->idle ($callback)
923
924=item $w = $loop->idle_ns ($callback)
679 925
680Call the callback when there are no other pending watchers of the same or 926Call the callback when there are no other pending watchers of the same or
681higher priority (excluding check, prepare and other idle watchers of the 927higher priority (excluding check, prepare and other idle watchers of the
682same or lower priority, of course). They are called idle watchers because 928same or lower priority, of course). They are called idle watchers because
683when the watcher is the highest priority pending event in the process, the 929when the watcher is the highest priority pending event in the process, the
… …
706 952
707=item $w = EV::prepare $callback 953=item $w = EV::prepare $callback
708 954
709=item $w = EV::prepare_ns $callback 955=item $w = EV::prepare_ns $callback
710 956
957=item $w = $loop->prepare ($callback)
958
959=item $w = $loop->prepare_ns ($callback)
960
711Call the callback just before the process would block. You can still 961Call the callback just before the process would block. You can still
712create/modify any watchers at this point. 962create/modify any watchers at this point.
713 963
714See the EV::check watcher, below, for explanations and an example. 964See the EV::check watcher, below, for explanations and an example.
715 965
… …
724 974
725=item $w = EV::check $callback 975=item $w = EV::check $callback
726 976
727=item $w = EV::check_ns $callback 977=item $w = EV::check_ns $callback
728 978
979=item $w = $loop->check ($callback)
980
981=item $w = $loop->check_ns ($callback)
982
729Call the callback just after the process wakes up again (after it has 983Call the callback just after the process wakes up again (after it has
730gathered events), but before any other callbacks have been invoked. 984gathered events), but before any other callbacks have been invoked.
731 985
732This is used to integrate other event-based software into the EV 986This can be used to integrate other event-based software into the EV
733mainloop: You register a prepare callback and in there, you create io and 987mainloop: You register a prepare callback and in there, you create io and
734timer watchers as required by the other software. Here is a real-world 988timer watchers as required by the other software. Here is a real-world
735example of integrating Net::SNMP (with some details left out): 989example of integrating Net::SNMP (with some details left out):
736 990
737 our @snmp_watcher; 991 our @snmp_watcher;
… …
767 # make the dispatcher handle any new stuff 1021 # make the dispatcher handle any new stuff
768 ... not shown 1022 ... not shown
769 }; 1023 };
770 1024
771The callbacks of the created watchers will not be called as the watchers 1025The callbacks of the created watchers will not be called as the watchers
772are destroyed before this cna happen (remember EV::check gets called 1026are destroyed before this can happen (remember EV::check gets called
773first). 1027first).
774 1028
775The C<check_ns> variant doesn't start (activate) the newly created watcher. 1029The C<check_ns> variant doesn't start (activate) the newly created watcher.
1030
1031=item EV::CHECK constant issues
1032
1033Like all other watcher types, there is a bitmask constant for use in
1034C<$revents> and other places. The C<EV::CHECK> is special as it has
1035the same name as the C<CHECK> sub called by Perl. This doesn't cause
1036big issues on newer perls (beginning with 5.8.9), but it means thatthe
1037constant must be I<inlined>, i.e. runtime calls will not work. That means
1038that as long as you always C<use EV> and then C<EV::CHECK> you are on the
1039safe side.
776 1040
777=back 1041=back
778 1042
779 1043
780=head3 FORK WATCHERS - the audacity to resume the event loop after a fork 1044=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
… …
787 1051
788=item $w = EV::fork $callback 1052=item $w = EV::fork $callback
789 1053
790=item $w = EV::fork_ns $callback 1054=item $w = EV::fork_ns $callback
791 1055
1056=item $w = $loop->fork ($callback)
1057
1058=item $w = $loop->fork_ns ($callback)
1059
792Call the callback before the event loop is resumed in the child process 1060Call the callback before the event loop is resumed in the child process
793after a fork. 1061after a fork.
794 1062
795The C<fork_ns> variant doesn't start (activate) the newly created watcher. 1063The C<fork_ns> variant doesn't start (activate) the newly created watcher.
1064
1065=back
1066
1067
1068=head3 EMBED WATCHERS - when one backend isn't enough...
1069
1070This is a rather advanced watcher type that lets you embed one event loop
1071into another (currently only IO events are supported in the embedded
1072loop, other types of watchers might be handled in a delayed or incorrect
1073fashion and must not be used).
1074
1075See the libev documentation at
1076L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
1077(locally installed as F<EV::libev>) for more details.
1078
1079In short, this watcher is most useful on BSD systems without working
1080kqueue to still be able to handle a large number of sockets:
1081
1082 my $socket_loop;
1083
1084 # check wether we use SELECT or POLL _and_ KQUEUE is supported
1085 if (
1086 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
1087 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
1088 ) {
1089 # use kqueue for sockets
1090 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
1091 }
1092
1093 # use the default loop otherwise
1094 $socket_loop ||= EV::default_loop;
1095
1096=over 4
1097
1098=item $w = EV::embed $otherloop[, $callback]
1099
1100=item $w = EV::embed_ns $otherloop[, $callback]
1101
1102=item $w = $loop->embed ($otherloop[, $callback])
1103
1104=item $w = $loop->embed_ns ($otherloop[, $callback])
1105
1106Call the callback when the embedded event loop (C<$otherloop>) has any
1107I/O activity. The C<$callback> is optional: if it is missing, then the
1108embedded event loop will be managed automatically (which is recommended),
1109otherwise you have to invoke C<sweep> yourself.
1110
1111The C<embed_ns> variant doesn't start (activate) the newly created watcher.
1112
1113=back
1114
1115=head3 ASYNC WATCHERS - how to wake up another event loop
1116
1117Async watchers are provided by EV, but have little use in perl directly,
1118as perl neither supports threads running in parallel nor direct access to
1119signal handlers or other contexts where they could be of value.
1120
1121It is, however, possible to use them from the XS level.
1122
1123Please see the libev documentation for further details.
1124
1125=over 4
1126
1127=item $w = EV::async $callback
1128
1129=item $w = EV::async_ns $callback
1130
1131=item $w->send
1132
1133=item $bool = $w->async_pending
796 1134
797=back 1135=back
798 1136
799 1137
800=head1 PERL SIGNALS 1138=head1 PERL SIGNALS
… …
811to be called on every event loop iteration by installing a C<EV::check> 1149to be called on every event loop iteration by installing a C<EV::check>
812watcher: 1150watcher:
813 1151
814 my $async_check = EV::check sub { }; 1152 my $async_check = EV::check sub { };
815 1153
816This ensures that perl shortly gets into control for a short time, and 1154This ensures that perl gets into control for a short time to handle any
817also ensures slower overall operation. 1155pending signals, and also ensures (slightly) slower overall operation.
818 1156
819=head1 THREADS 1157=head1 ITHREADS
820 1158
821Threads are not supported by this module in any way. Perl pseudo-threads 1159Ithreads are not supported by this module in any way. Perl pseudo-threads
822is evil stuff and must die. As soon as Perl gains real threads I will work 1160is evil stuff and must die. Real threads as provided by Coro are fully
823on thread support for it. 1161supported (and enhanced support is available via L<Coro::EV>).
824 1162
825=head1 FORK 1163=head1 FORK
826 1164
827Most of the "improved" event delivering mechanisms of modern operating 1165Most of the "improved" event delivering mechanisms of modern operating
828systems have quite a few problems with fork(2) (to put it bluntly: it is 1166systems have quite a few problems with fork(2) (to put it bluntly: it is
… …
850 1188
8511; 11891;
852 1190
853=head1 SEE ALSO 1191=head1 SEE ALSO
854 1192
1193L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS>
855L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as 1194(asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as event
856event loop), L<Coro::EV> (efficient coroutines with EV). 1195loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient thread
1196integration), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1197event-loop agnostic and portable event driven programming.
857 1198
858=head1 AUTHOR 1199=head1 AUTHOR
859 1200
860 Marc Lehmann <schmorp@schmorp.de> 1201 Marc Lehmann <schmorp@schmorp.de>
861 http://home.schmorp.de/ 1202 http://home.schmorp.de/
862 1203
863=cut 1204=cut
864 1205

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