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Revision 1.72 by root, Thu Dec 20 07:12:57 2007 UTC vs.
Revision 1.118 by root, Tue Jul 14 20:31:21 2009 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 55
56=head1 DESCRIPTION 56=head1 DESCRIPTION
57 57
58This module provides an interface to libev 58This module provides an interface to libev
59(L<http://software.schmorp.de/pkg/libev.html>). While the documentation 59(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
60below is comprehensive, one might also consult the documentation of libev 60below is comprehensive, one might also consult the documentation of
61itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on 61libev 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 62F<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 63discussion on the available backends, or how to force a specific backend
64because it has much more detailed information. 64with C<LIBEV_FLAGS>, or just about in any case because it has much more
65detailed information.
66
67This module is very fast and scalable. It is actually so fast that you
68can use it through the L<AnyEvent> module, stay portable to other event
69loops (if you don't rely on any watcher types not available through it)
70and still be faster than with any other event loop currently supported in
71Perl.
72
73=head2 MODULE EXPORTS
74
75This module does not export any symbols.
65 76
66=cut 77=cut
67 78
68package EV; 79package EV;
69 80
70use strict; 81use common::sense;
71 82
72BEGIN { 83BEGIN {
73 our $VERSION = '2.0'; 84 our $VERSION = '3.7';
74 use XSLoader; 85 use XSLoader;
75 XSLoader::load "EV", $VERSION; 86 XSLoader::load "EV", $VERSION;
76} 87}
77 88
78@EV::IO::ISA = 89@EV::IO::ISA =
… …
84@EV::Idle::ISA = 95@EV::Idle::ISA =
85@EV::Prepare::ISA = 96@EV::Prepare::ISA =
86@EV::Check::ISA = 97@EV::Check::ISA =
87@EV::Embed::ISA = 98@EV::Embed::ISA =
88@EV::Fork::ISA = 99@EV::Fork::ISA =
100@EV::Async::ISA =
89 "EV::Watcher"; 101 "EV::Watcher";
90 102
91@EV::Loop::Default::ISA = "EV::Loop"; 103@EV::Loop::Default::ISA = "EV::Loop";
104
105=head1 EVENT LOOPS
106
107EV supports multiple event loops: There is a single "default event loop"
108that can handle everything including signals and child watchers, and any
109number of "dynamic event loops" that can use different backends (with
110various limitations), but no child and signal watchers.
111
112You do not have to do anything to create the default event loop: When
113the module is loaded a suitable backend is selected on the premise of
114selecting a working backend (which for example rules out kqueue on most
115BSDs). Modules should, unless they have "special needs" always use the
116default loop as this is fastest (perl-wise), best supported by other
117modules (e.g. AnyEvent or Coro) and most portable event loop.
118
119For specific programs you can create additional event loops dynamically.
120
121If you want to take advantage of kqueue (which often works properly for
122sockets only) even though the default loop doesn't enable it, you can
123I<embed> a kqueue loop into the default loop: running the default loop
124will then also service the kqueue loop to some extent. See the example in
125the section about embed watchers for an example on how to achieve that.
126
127=over 4
128
129=item $loop = new EV::Loop [$flags]
130
131Create a new event loop as per the specified flags. Please refer to
132the C<ev_loop_new ()> function description in the libev documentation
133(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
134or locally-installed as F<EV::libev> manpage) for more info.
135
136The loop will automatically be destroyed when it is no longer referenced
137by any watcher and the loop object goes out of scope.
138
139If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
140is recommended, as only the default event loop is protected by this
141module. If you I<are> embedding this loop in the default loop, this is not
142necessary, as C<EV::embed> automatically does the right thing on fork.
143
144=item $loop->loop_fork
145
146Must be called after a fork in the child, before entering or continuing
147the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
148this function automatically, at some performance loss (refer to the libev
149documentation).
150
151=item $loop->loop_verify
152
153Calls C<ev_verify> to make internal consistency checks (for debugging
154libev) and abort the program if any data structures were found to be
155corrupted.
156
157=item $loop = EV::default_loop [$flags]
158
159Return the default loop (which is a singleton object). Since this module
160already creates the default loop with default flags, specifying flags here
161will not have any effect unless you destroy the default loop first, which
162isn't supported. So in short: don't do it, and if you break it, you get to
163keep the pieces.
164
165=back
166
92 167
93=head1 BASIC INTERFACE 168=head1 BASIC INTERFACE
94 169
95=over 4 170=over 4
96 171
… …
100throws an exception (with $@ containing the error). The default prints an 175throws an exception (with $@ containing the error). The default prints an
101informative message and continues. 176informative message and continues.
102 177
103If this callback throws an exception it will be silently ignored. 178If this callback throws an exception it will be silently ignored.
104 179
180=item $flags = EV::supported_backends
181
182=item $flags = EV::recommended_backends
183
184=item $flags = EV::embeddable_backends
185
186Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
187instance of EV, the set of recommended backends (supposed to be good) for
188this platform and the set of embeddable backends (see EMBED WATCHERS).
189
190=item EV::sleep $seconds
191
192Block the process for the given number of (fractional) seconds.
193
105=item $time = EV::time 194=item $time = EV::time
106 195
107Returns the current time in (fractional) seconds since the epoch. 196Returns the current time in (fractional) seconds since the epoch.
108 197
109=item $time = EV::now 198=item $time = EV::now
110 199
200=item $time = $loop->now
201
111Returns the time the last event loop iteration has been started. This 202Returns 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 203is the time that (relative) timers are based on, and referring to it is
113usually faster then calling EV::time. 204usually faster then calling EV::time.
114 205
115=item $method = EV::method 206=item EV::now_update
116 207
208=item $loop->now_update
209
210Establishes the current time by querying the kernel, updating the time
211returned by C<EV::now> in the progress. This is a costly operation and
212is usually done automatically within C<EV::loop>.
213
214This function is rarely useful, but when some event callback runs for a
215very long time without entering the event loop, updating libev's idea of
216the current time is a good idea.
217
218=item EV::suspend
219
220=item $loop->suspend
221
222=item EV::resume
223
224=item $loop->resume
225
226These two functions suspend and resume a loop, for use when the loop is
227not used for a while and timeouts should not be processed.
228
229A typical use case would be an interactive program such as a game: When
230the user presses C<^Z> to suspend the game and resumes it an hour later it
231would be best to handle timeouts as if no time had actually passed while
232the program was suspended. This can be achieved by calling C<suspend>
233in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
234C<resume> directly afterwards to resume timer processing.
235
236Effectively, all C<timer> watchers will be delayed by the time spend
237between C<suspend> and C<resume>, and all C<periodic> watchers
238will be rescheduled (that is, they will lose any events that would have
239occured while suspended).
240
241After calling C<suspend> you B<must not> call I<any> function on the given
242loop other than C<resume>, and you B<must not> call C<resume>
243without a previous call to C<suspend>.
244
245Calling C<suspend>/C<resume> has the side effect of updating the event
246loop time (see C<now_update>).
247
248=item $backend = EV::backend
249
250=item $backend = $loop->backend
251
117Returns an integer describing the backend used by libev (EV::METHOD_SELECT 252Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
118or EV::METHOD_EPOLL). 253or EV::BACKEND_EPOLL).
119 254
120=item EV::loop [$flags] 255=item EV::loop [$flags]
256
257=item $loop->loop ([$flags])
121 258
122Begin checking for events and calling callbacks. It returns when a 259Begin checking for events and calling callbacks. It returns when a
123callback calls EV::unloop. 260callback calls EV::unloop.
124 261
125The $flags argument can be one of the following: 262The $flags argument can be one of the following:
… …
128 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 265 EV::LOOP_ONESHOT block at most once (wait, but do not loop)
129 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 266 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
130 267
131=item EV::unloop [$how] 268=item EV::unloop [$how]
132 269
270=item $loop->unloop ([$how])
271
133When called with no arguments or an argument of EV::UNLOOP_ONE, makes the 272When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
134innermost call to EV::loop return. 273innermost call to EV::loop return.
135 274
136When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as 275When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
137fast as possible. 276fast as possible.
138 277
139=item $count = EV::loop_count 278=item $count = EV::loop_count
140 279
280=item $count = $loop->loop_count
281
141Return the number of times the event loop has polled for new 282Return the number of times the event loop has polled for new
142events. Sometiems useful as a generation counter. 283events. Sometimes useful as a generation counter.
143 284
144=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 285=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
286
287=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
145 288
146This function rolls together an I/O and a timer watcher for a single 289This function rolls together an I/O and a timer watcher for a single
147one-shot event without the need for managing a watcher object. 290one-shot event without the need for managing a watcher object.
148 291
149If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> 292If 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 298If timeout is C<undef> or negative, then there will be no
156timeout. Otherwise a EV::timer with this value will be started. 299timeout. Otherwise a EV::timer with this value will be started.
157 300
158When an error occurs or either the timeout or I/O watcher triggers, then 301When 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 302the 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>, 303you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
161C<EV::WRITE> and C<EV::TIMEOUT>). 304C<EV::WRITE> and C<EV::TIMEOUT>).
162 305
163EV::once doesn't return anything: the watchers stay active till either 306EV::once doesn't return anything: the watchers stay active till either
164of them triggers, then they will be stopped and freed, and the callback 307of them triggers, then they will be stopped and freed, and the callback
165invoked. 308invoked.
166 309
167=item EV::feed_fd_event ($fd, $revents) 310=item EV::feed_fd_event ($fd, $revents)
168 311
312=item $loop->feed_fd_event ($fd, $revents)
313
169Feed an event on a file descriptor into EV. EV will react to this call as 314Feed an event on a file descriptor into EV. EV will react to this call as
170if the readyness notifications specified by C<$revents> (a combination of 315if the readyness notifications specified by C<$revents> (a combination of
171C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. 316C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
172 317
173=item EV::feed_signal_event ($signal) 318=item EV::feed_signal_event ($signal)
174 319
175Feed a signal event into EV. EV will react to this call as if the signal 320Feed a signal event into EV. EV will react to this call as if the signal
176specified by C<$signal> had occured. 321specified by C<$signal> had occured.
177 322
178=back 323=item EV::set_io_collect_interval $time
179 324
325=item $loop->set_io_collect_interval ($time)
180 326
327=item EV::set_timeout_collect_interval $time
328
329=item $loop->set_timeout_collect_interval ($time)
330
331These advanced functions set the minimum block interval when polling for I/O events and the minimum
332wait interval for timer events. See the libev documentation at
333L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
334(locally installed as F<EV::libev>) for a more detailed discussion.
335
336=back
337
338
181=head2 WATCHER OBJECTS 339=head1 WATCHER OBJECTS
182 340
183A watcher is an object that gets created to record your interest in some 341A 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 342event. For instance, if you want to wait for STDIN to become readable, you
185would create an EV::io watcher for that: 343would create an EV::io watcher for that:
186 344
187 my $watcher = EV::io *STDIN, EV::READ, sub { 345 my $watcher = EV::io *STDIN, EV::READ, sub {
188 my ($watcher, $revents) = @_; 346 my ($watcher, $revents) = @_;
189 warn "yeah, STDIN should not be readable without blocking!\n" 347 warn "yeah, STDIN should now be readable without blocking!\n"
190 }; 348 };
191 349
192All watchers can be active (waiting for events) or inactive (paused). Only 350All watchers can be active (waiting for events) or inactive (paused). Only
193active watchers will have their callbacks invoked. All callbacks will be 351active watchers will have their callbacks invoked. All callbacks will be
194called with at least two arguments: the watcher and a bitmask of received 352called with at least two arguments: the watcher and a bitmask of received
195events. 353events.
196 354
197Each watcher type has its associated bit in revents, so you can use the 355Each watcher type has its associated bit in revents, so you can use the
198same callback for multiple watchers. The event mask is named after the 356same callback for multiple watchers. The event mask is named after the
199type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 357type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
200EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events 358EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
201(which can set both EV::READ and EV::WRITE bits), and EV::timer (which 359(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
202uses EV::TIMEOUT). 360uses EV::TIMEOUT).
203 361
204In the rare case where one wants to create a watcher but not start it at 362In the rare case where one wants to create a watcher but not start it at
… …
278Feed some events on this watcher into EV. EV will react to this call as if 436Feed some events on this watcher into EV. EV will react to this call as if
279the watcher had received the given C<$revents> mask. 437the watcher had received the given C<$revents> mask.
280 438
281=item $revents = $w->clear_pending 439=item $revents = $w->clear_pending
282 440
283If the watcher is pending, this function returns clears its pending status 441If the watcher is pending, this function clears its pending status and
284and returns its C<$revents> bitset (as if its callback was invoked). If the 442returns its C<$revents> bitset (as if its callback was invoked). If the
285watcher isn't pending it does nothing and returns C<0>. 443watcher isn't pending it does nothing and returns C<0>.
286 444
287=item $previous_state = $w->keepalive ($bool) 445=item $previous_state = $w->keepalive ($bool)
288 446
289Normally, C<EV::loop> will return when there are no active watchers 447Normally, 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 448(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), 449convinient 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 450call 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 :). 451finished (or they forgot to register some watchers for their task :).
294 452
295Sometimes, however, this gets in your way, for example when you the module 453Sometimes, 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 454that 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 455as a long-living watcher (for example a DNS client module written by
298somebody else even). Then you might want any outstanding requests to be 456somebody 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 457handled, but you would not want to keep C<EV::loop> from returning just
300because you happen to have this long-running UDP port watcher. 458because you happen to have this long-running UDP port watcher.
301 459
302In this case you can clear the keepalive status, which means that even 460In 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. 461though your watcher is active, it won't keep C<EV::loop> from returning.
304 462
305The initial value for keepalive is true (enabled), and you cna change it 463The initial value for keepalive is true (enabled), and you can change it
306any time. 464any time.
307 465
308Example: Register an I/O watcher for some UDP socket but do not keep the 466Example: Register an I/O watcher for some UDP socket but do not keep the
309event loop from running just because of that watcher. 467event loop from running just because of that watcher.
310 468
311 my $udp_socket = ... 469 my $udp_socket = ...
312 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 470 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
313 $udp_watcher->keepalive (0); 471 $udp_watcher->keepalive (0);
314 472
315=back 473=item $loop = $w->loop
316 474
475Return the loop that this watcher is attached to.
317 476
477=back
478
479
318=head2 WATCHER TYPES 480=head1 WATCHER TYPES
319 481
320Each of the following subsections describes a single watcher type. 482Each of the following subsections describes a single watcher type.
321 483
322=head3 I/O WATCHERS - is this file descriptor readable or writable? 484=head3 I/O WATCHERS - is this file descriptor readable or writable?
323 485
324=over 4 486=over 4
325 487
326=item $w = EV::io $fileno_or_fh, $eventmask, $callback 488=item $w = EV::io $fileno_or_fh, $eventmask, $callback
327 489
328=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 490=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
491
492=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
493
494=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
329 495
330As long as the returned watcher object is alive, call the C<$callback> 496As long as the returned watcher object is alive, call the C<$callback>
331when at least one of events specified in C<$eventmask> occurs. 497when at least one of events specified in C<$eventmask> occurs.
332 498
333The $eventmask can be one or more of these constants ORed together: 499The $eventmask can be one or more of these constants ORed together:
… …
362=over 4 528=over 4
363 529
364=item $w = EV::timer $after, $repeat, $callback 530=item $w = EV::timer $after, $repeat, $callback
365 531
366=item $w = EV::timer_ns $after, $repeat, $callback 532=item $w = EV::timer_ns $after, $repeat, $callback
533
534=item $w = $loop->timer ($after, $repeat, $callback)
535
536=item $w = $loop->timer_ns ($after, $repeat, $callback)
367 537
368Calls the callback after C<$after> seconds (which may be fractional). If 538Calls the callback after C<$after> seconds (which may be fractional). If
369C<$repeat> is non-zero, the timer will be restarted (with the $repeat 539C<$repeat> is non-zero, the timer will be restarted (with the $repeat
370value as $after) after the callback returns. 540value as $after) after the callback returns.
371 541
… …
412=over 4 582=over 4
413 583
414=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback 584=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
415 585
416=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 586=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
587
588=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
589
590=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
417 591
418Similar to EV::timer, but is not based on relative timeouts but on 592Similar to EV::timer, but is not based on relative timeouts but on
419absolute times. Apart from creating "simple" timers that trigger "at" the 593absolute times. Apart from creating "simple" timers that trigger "at" the
420specified time, it can also be used for non-drifting absolute timers and 594specified time, it can also be used for non-drifting absolute timers and
421more complex, cron-like, setups that are not adversely affected by time 595more complex, cron-like, setups that are not adversely affected by time
… …
431This time simply fires at the wallclock time C<$at> and doesn't repeat. It 605This time simply fires at the wallclock time C<$at> and doesn't repeat. It
432will not adjust when a time jump occurs, that is, if it is to be run 606will not adjust when a time jump occurs, that is, if it is to be run
433at January 1st 2011 then it will run when the system time reaches or 607at January 1st 2011 then it will run when the system time reaches or
434surpasses this time. 608surpasses this time.
435 609
436=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 610=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
437 611
438In this mode the watcher will always be scheduled to time out at the 612In this mode the watcher will always be scheduled to time out at the
439next C<$at + N * $interval> time (for some integer N) and then repeat, 613next C<$at + N * $interval> time (for some integer N) and then repeat,
440regardless of any time jumps. 614regardless of any time jumps.
441 615
… …
459time the periodic watcher gets scheduled, the reschedule callback 633time the periodic watcher gets scheduled, the reschedule callback
460($reschedule_cb) will be called with the watcher as first, and the current 634($reschedule_cb) will be called with the watcher as first, and the current
461time as second argument. 635time as second argument.
462 636
463I<This callback MUST NOT stop or destroy this or any other periodic 637I<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 638watcher, ever, and MUST NOT call any event loop functions or methods>. If
465afterwards. 639you need to stop it, return 1e30 and stop it afterwards. You may create
640and start a C<EV::prepare> watcher for this task.
466 641
467It must return the next time to trigger, based on the passed time value 642It 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 643(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 644argument). It will usually be called just before the callback will be
470might be called at other times, too. 645triggered, but might be called at other times, too.
471 646
472This can be used to create very complex timers, such as a timer that 647This 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 648triggers 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 649midnight, 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 650in about the same space (without requiring elaborate modules), drop me a
… …
542 717
543=head3 CHILD WATCHERS - watch out for process status changes 718=head3 CHILD WATCHERS - watch out for process status changes
544 719
545=over 4 720=over 4
546 721
547=item $w = EV::child $pid, $callback 722=item $w = EV::child $pid, $trace, $callback
548 723
549=item $w = EV::child_ns $pid, $callback 724=item $w = EV::child_ns $pid, $trace, $callback
550 725
726=item $w = $loop->child ($pid, $trace, $callback)
727
728=item $w = $loop->child_ns ($pid, $trace, $callback)
729
551Call the callback when a status change for pid C<$pid> (or any pid if 730Call 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 731if C<$pid> is 0) has been received (a status change happens when the
732process terminates or is killed, or, when trace is true, additionally when
733it is stopped or continued). More precisely: when the process receives
553a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all 734a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
554changed/zombie children and call the callback. 735changed/zombie children and call the callback.
555 736
556It is valid (and fully supported) to install a child watcher after a child 737It 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 738has 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 745You can have as many pid watchers per pid as you want, they will all be
565called. 746called.
566 747
567The C<child_ns> variant doesn't start (activate) the newly created watcher. 748The C<child_ns> variant doesn't start (activate) the newly created watcher.
568 749
569=item $w->set ($pid) 750=item $w->set ($pid, $trace)
570 751
571Reconfigures the watcher, see the constructor above for details. Can be called at 752Reconfigures the watcher, see the constructor above for details. Can be called at
572any time. 753any time.
573 754
574=item $current_pid = $w->pid 755=item $current_pid = $w->pid
575 756
576=item $old_pid = $w->pid ($new_pid)
577
578Returns the previously set process id and optionally set a new one. 757Returns the previously set process id and optionally set a new one.
579 758
580=item $exit_status = $w->rstatus 759=item $exit_status = $w->rstatus
581 760
582Return the exit/wait status (as returned by waitpid, see the waitpid entry 761Return the exit/wait status (as returned by waitpid, see the waitpid entry
… …
595=over 4 774=over 4
596 775
597=item $w = EV::stat $path, $interval, $callback 776=item $w = EV::stat $path, $interval, $callback
598 777
599=item $w = EV::stat_ns $path, $interval, $callback 778=item $w = EV::stat_ns $path, $interval, $callback
779
780=item $w = $loop->stat ($path, $interval, $callback)
781
782=item $w = $loop->stat_ns ($path, $interval, $callback)
600 783
601Call the callback when a file status change has been detected on 784Call the callback when a file status change has been detected on
602C<$path>. The C<$path> does not need to exist, changing from "path exists" 785C<$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. 786to "path does not exist" is a status change like any other.
604 787
… …
674=over 4 857=over 4
675 858
676=item $w = EV::idle $callback 859=item $w = EV::idle $callback
677 860
678=item $w = EV::idle_ns $callback 861=item $w = EV::idle_ns $callback
862
863=item $w = $loop->idle ($callback)
864
865=item $w = $loop->idle_ns ($callback)
679 866
680Call the callback when there are no other pending watchers of the same or 867Call the callback when there are no other pending watchers of the same or
681higher priority (excluding check, prepare and other idle watchers of the 868higher priority (excluding check, prepare and other idle watchers of the
682same or lower priority, of course). They are called idle watchers because 869same or lower priority, of course). They are called idle watchers because
683when the watcher is the highest priority pending event in the process, the 870when the watcher is the highest priority pending event in the process, the
… …
706 893
707=item $w = EV::prepare $callback 894=item $w = EV::prepare $callback
708 895
709=item $w = EV::prepare_ns $callback 896=item $w = EV::prepare_ns $callback
710 897
898=item $w = $loop->prepare ($callback)
899
900=item $w = $loop->prepare_ns ($callback)
901
711Call the callback just before the process would block. You can still 902Call the callback just before the process would block. You can still
712create/modify any watchers at this point. 903create/modify any watchers at this point.
713 904
714See the EV::check watcher, below, for explanations and an example. 905See the EV::check watcher, below, for explanations and an example.
715 906
… …
723=over 4 914=over 4
724 915
725=item $w = EV::check $callback 916=item $w = EV::check $callback
726 917
727=item $w = EV::check_ns $callback 918=item $w = EV::check_ns $callback
919
920=item $w = $loop->check ($callback)
921
922=item $w = $loop->check_ns ($callback)
728 923
729Call the callback just after the process wakes up again (after it has 924Call the callback just after the process wakes up again (after it has
730gathered events), but before any other callbacks have been invoked. 925gathered events), but before any other callbacks have been invoked.
731 926
732This is used to integrate other event-based software into the EV 927This is used to integrate other event-based software into the EV
… …
767 # make the dispatcher handle any new stuff 962 # make the dispatcher handle any new stuff
768 ... not shown 963 ... not shown
769 }; 964 };
770 965
771The callbacks of the created watchers will not be called as the watchers 966The callbacks of the created watchers will not be called as the watchers
772are destroyed before this cna happen (remember EV::check gets called 967are destroyed before this can happen (remember EV::check gets called
773first). 968first).
774 969
775The C<check_ns> variant doesn't start (activate) the newly created watcher. 970The C<check_ns> variant doesn't start (activate) the newly created watcher.
776 971
777=back 972=back
… …
787 982
788=item $w = EV::fork $callback 983=item $w = EV::fork $callback
789 984
790=item $w = EV::fork_ns $callback 985=item $w = EV::fork_ns $callback
791 986
987=item $w = $loop->fork ($callback)
988
989=item $w = $loop->fork_ns ($callback)
990
792Call the callback before the event loop is resumed in the child process 991Call the callback before the event loop is resumed in the child process
793after a fork. 992after a fork.
794 993
795The C<fork_ns> variant doesn't start (activate) the newly created watcher. 994The C<fork_ns> variant doesn't start (activate) the newly created watcher.
995
996=back
997
998
999=head3 EMBED WATCHERS - when one backend isn't enough...
1000
1001This is a rather advanced watcher type that lets you embed one event loop
1002into another (currently only IO events are supported in the embedded
1003loop, other types of watchers might be handled in a delayed or incorrect
1004fashion and must not be used).
1005
1006See the libev documentation at
1007L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
1008(locally installed as F<EV::libev>) for more details.
1009
1010In short, this watcher is most useful on BSD systems without working
1011kqueue to still be able to handle a large number of sockets:
1012
1013 my $socket_loop;
1014
1015 # check wether we use SELECT or POLL _and_ KQUEUE is supported
1016 if (
1017 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
1018 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
1019 ) {
1020 # use kqueue for sockets
1021 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
1022 }
1023
1024 # use the default loop otherwise
1025 $socket_loop ||= EV::default_loop;
1026
1027=over 4
1028
1029=item $w = EV::embed $otherloop[, $callback]
1030
1031=item $w = EV::embed_ns $otherloop[, $callback]
1032
1033=item $w = $loop->embed ($otherloop[, $callback])
1034
1035=item $w = $loop->embed_ns ($otherloop[, $callback])
1036
1037Call the callback when the embedded event loop (C<$otherloop>) has any
1038I/O activity. The C<$callback> is optional: if it is missing, then the
1039embedded event loop will be managed automatically (which is recommended),
1040otherwise you have to invoke C<sweep> yourself.
1041
1042The C<embed_ns> variant doesn't start (activate) the newly created watcher.
1043
1044=back
1045
1046=head3 ASYNC WATCHERS - how to wake up another event loop
1047
1048Async watchers are provided by EV, but have little use in perl directly,
1049as perl neither supports threads running in parallel nor direct access to
1050signal handlers or other contexts where they could be of value.
1051
1052It is, however, possible to use them from the XS level.
1053
1054Please see the libev documentation for further details.
1055
1056=over 4
1057
1058=item $w = EV::async $callback
1059
1060=item $w = EV::async_ns $callback
1061
1062=item $w->send
1063
1064=item $bool = $w->async_pending
796 1065
797=back 1066=back
798 1067
799 1068
800=head1 PERL SIGNALS 1069=head1 PERL SIGNALS
… …
811to be called on every event loop iteration by installing a C<EV::check> 1080to be called on every event loop iteration by installing a C<EV::check>
812watcher: 1081watcher:
813 1082
814 my $async_check = EV::check sub { }; 1083 my $async_check = EV::check sub { };
815 1084
816This ensures that perl shortly gets into control for a short time, and 1085This ensures that perl gets into control for a short time to handle any
817also ensures slower overall operation. 1086pending signals, and also ensures (slightly) slower overall operation.
818 1087
819=head1 THREADS 1088=head1 ITHREADS
820 1089
821Threads are not supported by this module in any way. Perl pseudo-threads 1090Ithreads 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 1091is evil stuff and must die. Real threads as provided by Coro are fully
823on thread support for it. 1092supported (and enhanced support is available via L<Coro::EV>).
824 1093
825=head1 FORK 1094=head1 FORK
826 1095
827Most of the "improved" event delivering mechanisms of modern operating 1096Most of the "improved" event delivering mechanisms of modern operating
828systems have quite a few problems with fork(2) (to put it bluntly: it is 1097systems have quite a few problems with fork(2) (to put it bluntly: it is
… …
850 1119
8511; 11201;
852 1121
853=head1 SEE ALSO 1122=head1 SEE ALSO
854 1123
855L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as 1124L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
856event loop), L<Coro::EV> (efficient coroutines with EV). 1125event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
1126coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1127event-loop agnostic and portable event driven programming.
857 1128
858=head1 AUTHOR 1129=head1 AUTHOR
859 1130
860 Marc Lehmann <schmorp@schmorp.de> 1131 Marc Lehmann <schmorp@schmorp.de>
861 http://home.schmorp.de/ 1132 http://home.schmorp.de/
862 1133
863=cut 1134=cut
864 1135

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