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Revision 1.79 by root, Sat Dec 22 16:37:07 2007 UTC vs.
Revision 1.131 by root, Sun Dec 5 11:45:22 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 = '4.01';
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
… …
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 can 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).
130 190
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
131=item $loop = EV::default_loop [$flags] 197=item $loop = EV::default_loop [$flags]
132 198
133Return the default loop (which is a singleton object). 199Return the default loop (which is a singleton object). Since this module
200already creates the default loop with default flags, specifying flags here
201will not have any effect unless you destroy the default loop first, which
202isn't supported. So in short: don't do it, and if you break it, you get to
203keep the pieces.
134 204
135=back 205=back
136 206
137 207
138=head1 BASIC INTERFACE 208=head1 BASIC INTERFACE
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155 225
156Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this 226Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
157instance of EV, the set of recommended backends (supposed to be good) for 227instance of EV, the set of recommended backends (supposed to be good) for
158this platform and the set of embeddable backends (see EMBED WATCHERS). 228this platform and the set of embeddable backends (see EMBED WATCHERS).
159 229
230=item EV::sleep $seconds
231
232Block the process for the given number of (fractional) seconds.
233
160=item $time = EV::time 234=item $time = EV::time
161 235
162Returns the current time in (fractional) seconds since the epoch. 236Returns the current time in (fractional) seconds since the epoch.
163 237
164=item $time = EV::now 238=item $time = EV::now
165 239
166=item $time = $loop->now 240=item $time = $loop->now
167 241
168Returns the time the last event loop iteration has been started. This 242Returns the time the last event loop iteration has been started. This
169is 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
170usually faster then calling EV::time. 244usually faster then calling EV::time.
171 245
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
172=item $backend = EV::backend 288=item $backend = EV::backend
173 289
174=item $backend = $loop->backend 290=item $backend = $loop->backend
175 291
176Returns an integer describing the backend used by libev (EV::METHOD_SELECT 292Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
177or EV::METHOD_EPOLL). 293or EV::BACKEND_EPOLL).
178 294
179=item EV::loop [$flags] 295=item EV::loop [$flags]
180 296
181=item $loop->loop ([$flags]) 297=item $loop->loop ([$flags])
182 298
… …
202=item $count = EV::loop_count 318=item $count = EV::loop_count
203 319
204=item $count = $loop->loop_count 320=item $count = $loop->loop_count
205 321
206Return the number of times the event loop has polled for new 322Return the number of times the event loop has polled for new
207events. Sometiems useful as a generation counter. 323events. Sometimes useful as a generation counter.
208 324
209=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 325=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
210 326
211=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 327=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
212 328
… …
223timeout. Otherwise a EV::timer with this value will be started. 339timeout. Otherwise a EV::timer with this value will be started.
224 340
225When 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
226the callback will be called with the received event set (in general 342the callback will be called with the received event set (in general
227you 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>,
228C<EV::WRITE> and C<EV::TIMEOUT>). 344C<EV::WRITE> and C<EV::TIMER>).
229 345
230EV::once doesn't return anything: the watchers stay active till either 346EV::once doesn't return anything: the watchers stay active till either
231of 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
232invoked. 348invoked.
233 349
… …
252 368
253=item $loop->set_timeout_collect_interval ($time) 369=item $loop->set_timeout_collect_interval ($time)
254 370
255These advanced functions set the minimum block interval when polling for I/O events and the minimum 371These advanced functions set the minimum block interval when polling for I/O events and the minimum
256wait interval for timer events. See the libev documentation at 372wait interval for timer events. See the libev documentation at
257L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> for 373L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
258a more detailed discussion. 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.
259 387
260=back 388=back
261 389
262 390
263=head1 WATCHER OBJECTS 391=head1 WATCHER OBJECTS
264 392
265A 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
266event. 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
267would create an EV::io watcher for that: 395would create an EV::io watcher for that:
268 396
269 my $watcher = EV::io *STDIN, EV::READ, sub { 397 my $watcher = EV::io *STDIN, EV::READ, sub {
270 my ($watcher, $revents) = @_; 398 my ($watcher, $revents) = @_;
271 warn "yeah, STDIN should now be readable without blocking!\n" 399 warn "yeah, STDIN should now be readable without blocking!\n"
272 }; 400 };
273 401
274All watchers can be active (waiting for events) or inactive (paused). Only 402All watchers can be active (waiting for events) or inactive (paused). Only
275active watchers will have their callbacks invoked. All callbacks will be 403active watchers will have their callbacks invoked. All callbacks will be
276called 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
277events. 405events.
278 406
279Each 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
280same callback for multiple watchers. The event mask is named after the 408same callback for multiple watchers. The event mask is named after the
281type, 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,
282EV::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
283(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).
284uses EV::TIMEOUT).
285 412
286In 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
287the 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
288its 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.
289 416
… …
368 495
369=item $previous_state = $w->keepalive ($bool) 496=item $previous_state = $w->keepalive ($bool)
370 497
371Normally, C<EV::loop> will return when there are no active watchers 498Normally, C<EV::loop> will return when there are no active watchers
372(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
373convinient because it allows you to start your watchers (and your jobs), 500convenient because it allows you to start your watchers (and your jobs),
374call 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
375finished (or they forgot to register some watchers for their task :). 502finished (or they forgot to register some watchers for their task :).
376 503
377Sometimes, however, this gets in your way, for example when the module 504Sometimes, however, this gets in your way, for example when the module
378that 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
… …
382because you happen to have this long-running UDP port watcher. 509because you happen to have this long-running UDP port watcher.
383 510
384In 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
385though 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.
386 513
387The 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
388any time. 515any time.
389 516
390Example: 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
391event loop from running just because of that watcher. 518event loop from running just because of that watcher.
392 519
393 my $udp_socket = ... 520 my $udp_socket = ...
394 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 521 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
395 $1000udp_watcher->keepalive (0); 522 $udp_watcher->keepalive (0);
396 523
397=item $loop = $w->loop 524=item $loop = $w->loop
398 525
399Return the loop that this watcher is attached to. 526Return the loop that this watcher is attached to.
400 527
… …
529This time simply fires at the wallclock time C<$at> and doesn't repeat. It 656This time simply fires at the wallclock time C<$at> and doesn't repeat. It
530will not adjust when a time jump occurs, that is, if it is to be run 657will not adjust when a time jump occurs, that is, if it is to be run
531at January 1st 2011 then it will run when the system time reaches or 658at January 1st 2011 then it will run when the system time reaches or
532surpasses this time. 659surpasses this time.
533 660
534=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 661=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
535 662
536In this mode the watcher will always be scheduled to time out at the 663In this mode the watcher will always be scheduled to time out at the
537next C<$at + N * $interval> time (for some integer N) and then repeat, 664next C<$at + N * $interval> time (for some integer N) and then repeat,
538regardless of any time jumps. 665regardless of any time jumps.
539 666
… …
557time the periodic watcher gets scheduled, the reschedule callback 684time the periodic watcher gets scheduled, the reschedule callback
558($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
559time as second argument. 686time as second argument.
560 687
561I<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
562watcher, 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
563afterwards. 690you need to stop it, return 1e30 and stop it afterwards. You may create
691and start a C<EV::prepare> watcher for this task.
564 692
565It 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
566(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
567will usually be called just before the callback will be triggered, but 695argument). It will usually be called just before the callback will be
568might be called at other times, too. 696triggered, but might be called at other times, too.
569 697
570This 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
571triggers on each midnight, local time (actually 24 hours after the last 699triggers on each midnight, local time (actually 24 hours after the last
572midnight, 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
573in about the same space (without requiring elaborate modules), drop me a 701in about the same space (without requiring elaborate modules), drop me a
… …
609 737
610=item $w = EV::signal $signal, $callback 738=item $w = EV::signal $signal, $callback
611 739
612=item $w = EV::signal_ns $signal, $callback 740=item $w = EV::signal_ns $signal, $callback
613 741
742=item $w = $loop->signal ($signal, $callback)
743
744=item $w = $loop->signal_ns ($signal, $callback)
745
614Call 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
615number 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.
616 752
617EV 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
618component 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,
619and 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
620add/remove callbacks to C<%SIG>, so watch out. 756add/remove callbacks to C<%SIG>, so watch out.
… …
640 776
641=head3 CHILD WATCHERS - watch out for process status changes 777=head3 CHILD WATCHERS - watch out for process status changes
642 778
643=over 4 779=over 4
644 780
645=item $w = EV::child $pid, $callback 781=item $w = EV::child $pid, $trace, $callback
646 782
647=item $w = EV::child_ns $pid, $callback 783=item $w = EV::child_ns $pid, $trace, $callback
648 784
649=item $w = $loop->child ($pid, $callback) 785=item $w = $loop->child ($pid, $trace, $callback)
650 786
651=item $w = $loop->child_ns ($pid, $callback) 787=item $w = $loop->child_ns ($pid, $trace, $callback)
652 788
653Call the callback when a status change for pid C<$pid> (or any pid if 789Call the callback when a status change for pid C<$pid> (or any pid
654C<$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
655a 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
656changed/zombie children and call the callback. 794changed/zombie children and call the callback.
657 795
658It 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
659has 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
… …
666You 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
667called. 805called.
668 806
669The 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.
670 808
671=item $w->set ($pid) 809=item $w->set ($pid, $trace)
672 810
673Reconfigures 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
674any time. 812any time.
675 813
676=item $current_pid = $w->pid 814=item $current_pid = $w->pid
677
678=item $old_pid = $w->pid ($new_pid)
679 815
680Returns the previously set process id and optionally set a new one. 816Returns the previously set process id and optionally set a new one.
681 817
682=item $exit_status = $w->rstatus 818=item $exit_status = $w->rstatus
683 819
… …
845=item $w = $loop->check_ns ($callback) 981=item $w = $loop->check_ns ($callback)
846 982
847Call 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
848gathered events), but before any other callbacks have been invoked. 984gathered events), but before any other callbacks have been invoked.
849 985
850This is used to integrate other event-based software into the EV 986This can be used to integrate other event-based software into the EV
851mainloop: 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
852timer 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
853example of integrating Net::SNMP (with some details left out): 989example of integrating Net::SNMP (with some details left out):
854 990
855 our @snmp_watcher; 991 our @snmp_watcher;
… …
885 # make the dispatcher handle any new stuff 1021 # make the dispatcher handle any new stuff
886 ... not shown 1022 ... not shown
887 }; 1023 };
888 1024
889The 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
890are destroyed before this cna happen (remember EV::check gets called 1026are destroyed before this can happen (remember EV::check gets called
891first). 1027first).
892 1028
893The 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.
894 1040
895=back 1041=back
896 1042
897 1043
898=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
… …
926loop, other types of watchers might be handled in a delayed or incorrect 1072loop, other types of watchers might be handled in a delayed or incorrect
927fashion and must not be used). 1073fashion and must not be used).
928 1074
929See the libev documentation at 1075See the libev documentation at
930L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> 1076L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
931for more details. 1077(locally installed as F<EV::libev>) for more details.
932 1078
933In short, this watcher is most useful on BSD systems without working 1079In short, this watcher is most useful on BSD systems without working
934kqueue to still be able to handle a large number of sockets: 1080kqueue to still be able to handle a large number of sockets:
935 1081
936 my $socket_loop; 1082 my $socket_loop;
937 1083
938 # check wether we use SELECT or POLL _and_ KQUEUE is supported 1084 # check wether we use SELECT or POLL _and_ KQUEUE is supported
939 if ( 1085 if (
940 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 1086 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
941 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 1087 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
942 ) { 1088 ) {
943 # use kqueue for sockets 1089 # use kqueue for sockets
944 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 1090 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
945 } 1091 }
946 1092
947 # use the default loop otherwise 1093 # use the default loop otherwise
948 $socket_loop ||= EV::default_loop; 1094 $socket_loop ||= EV::default_loop;
949 1095
950=over 4 1096=over 4
951 1097
952=item $w = EV::embed $otherloop, $callback 1098=item $w = EV::embed $otherloop[, $callback]
953 1099
954=item $w = EV::embed_ns $otherloop, $callback 1100=item $w = EV::embed_ns $otherloop[, $callback]
955 1101
956=item $w = $loop->embed ($otherloop, $callback) 1102=item $w = $loop->embed ($otherloop[, $callback])
957 1103
958=item $w = $loop->embed_ns ($otherloop, $callback) 1104=item $w = $loop->embed_ns ($otherloop[, $callback])
959 1105
960Call the callback when the embedded event loop (C<$otherloop>) has any 1106Call the callback when the embedded event loop (C<$otherloop>) has any
961I/O activity. The C<$callback> should alwas be specified as C<undef> in 1107I/O activity. The C<$callback> is optional: if it is missing, then the
962this version of EV, which means the embedded event loop will be managed 1108embedded event loop will be managed automatically (which is recommended),
963automatically. 1109otherwise you have to invoke C<sweep> yourself.
964 1110
965The C<embed_ns> variant doesn't start (activate) the newly created watcher. 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
966 1134
967=back 1135=back
968 1136
969 1137
970=head1 PERL SIGNALS 1138=head1 PERL SIGNALS
… …
984 my $async_check = EV::check sub { }; 1152 my $async_check = EV::check sub { };
985 1153
986This ensures that perl gets into control for a short time to handle any 1154This ensures that perl gets into control for a short time to handle any
987pending signals, and also ensures (slightly) slower overall operation. 1155pending signals, and also ensures (slightly) slower overall operation.
988 1156
989=head1 THREADS 1157=head1 ITHREADS
990 1158
991Threads 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
992is 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
993on thread support for it. 1161supported (and enhanced support is available via L<Coro::EV>).
994 1162
995=head1 FORK 1163=head1 FORK
996 1164
997Most of the "improved" event delivering mechanisms of modern operating 1165Most of the "improved" event delivering mechanisms of modern operating
998systems 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
… …
1020 1188
10211; 11891;
1022 1190
1023=head1 SEE ALSO 1191=head1 SEE ALSO
1024 1192
1193L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS>
1025L<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
1026event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient 1195loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient thread
1027coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP). 1196integration), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1197event-loop agnostic and portable event driven programming.
1028 1198
1029=head1 AUTHOR 1199=head1 AUTHOR
1030 1200
1031 Marc Lehmann <schmorp@schmorp.de> 1201 Marc Lehmann <schmorp@schmorp.de>
1032 http://home.schmorp.de/ 1202 http://home.schmorp.de/
1033 1203
1034=cut 1204=cut
1035 1205

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