ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/EV/EV.pm
(Generate patch)

Comparing EV/EV.pm (file contents):
Revision 1.77 by root, Sat Dec 22 11:44:50 2007 UTC vs.
Revision 1.129 by root, Thu Oct 21 15:13:42 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 = '4.00';
74 use XSLoader; 125 use XSLoader;
75 XSLoader::load "EV", $VERSION; 126 XSLoader::load "EV", $VERSION;
76} 127}
77 128
78@EV::IO::ISA = 129@EV::IO::ISA =
84@EV::Idle::ISA = 135@EV::Idle::ISA =
85@EV::Prepare::ISA = 136@EV::Prepare::ISA =
86@EV::Check::ISA = 137@EV::Check::ISA =
87@EV::Embed::ISA = 138@EV::Embed::ISA =
88@EV::Fork::ISA = 139@EV::Fork::ISA =
140@EV::Async::ISA =
89 "EV::Watcher"; 141 "EV::Watcher";
90 142
91@EV::Loop::Default::ISA = "EV::Loop"; 143@EV::Loop::Default::ISA = "EV::Loop";
92 144
93=head1 EVENT LOOPS 145=head1 EVENT LOOPS
102selecting a working backend (which for example rules out kqueue on most 154selecting a working backend (which for example rules out kqueue on most
103BSDs). Modules should, unless they have "special needs" always use the 155BSDs). Modules should, unless they have "special needs" always use the
104default loop as this is fastest (perl-wise), best supported by other 156default loop as this is fastest (perl-wise), best supported by other
105modules (e.g. AnyEvent or Coro) and most portable event loop. 157modules (e.g. AnyEvent or Coro) and most portable event loop.
106 158
107For specific programs you cna create additional event loops dynamically. 159For specific programs you can create additional event loops dynamically.
108 160
109=over 4 161If you want to take advantage of kqueue (which often works properly for
162sockets only) even though the default loop doesn't enable it, you can
163I<embed> a kqueue loop into the default loop: running the default loop
164will then also service the kqueue loop to some extent. See the example in
165the section about embed watchers for an example on how to achieve that.
110 166
167=over 4
168
111=item $loop = new EV::loop [$flags] 169=item $loop = new EV::Loop [$flags]
112 170
113Create a new event loop as per the specified flags. Please refer to the 171Create a new event loop as per the specified flags. Please refer to
114C<ev_loop_new ()> function description in the libev documentation 172the C<ev_loop_new ()> function description in the libev documentation
115(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>) 173(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
116for more info. 174or locally-installed as F<EV::libev> manpage) for more info.
117 175
118The loop will automatically be destroyed when it is no longer referenced 176The loop will automatically be destroyed when it is no longer referenced
119by any watcher and the loop object goes out of scope. 177by any watcher and the loop object goes out of scope.
120 178
121Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop 179If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
122is protected by this module. 180is recommended, as only the default event loop is protected by this
181module. If you I<are> embedding this loop in the default loop, this is not
182necessary, as C<EV::embed> automatically does the right thing on fork.
123 183
124=item $loop->loop_fork 184=item $loop->loop_fork
125 185
126Must be called after a fork in the child, before entering or continuing 186Must be called after a fork in the child, before entering or continuing
127the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls 187the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
128this fucntion automatically, at some performance loss (refer to the libev 188this function automatically, at some performance loss (refer to the libev
129documentation). 189documentation).
190
191=item $loop->loop_verify
192
193Calls C<ev_verify> to make internal consistency checks (for debugging
194libev) and abort the program if any data structures were found to be
195corrupted.
196
197=item $loop = EV::default_loop [$flags]
198
199Return the default loop (which is a singleton object). Since this module
200already creates the default loop with default flags, specifying flags here
201will not have any effect unless you destroy the default loop first, which
202isn't supported. So in short: don't do it, and if you break it, you get to
203keep the pieces.
130 204
131=back 205=back
132 206
133 207
134=head1 BASIC INTERFACE 208=head1 BASIC INTERFACE
141throws an exception (with $@ containing the error). The default prints an 215throws an exception (with $@ containing the error). The default prints an
142informative message and continues. 216informative message and continues.
143 217
144If this callback throws an exception it will be silently ignored. 218If this callback throws an exception it will be silently ignored.
145 219
220=item $flags = EV::supported_backends
221
222=item $flags = EV::recommended_backends
223
224=item $flags = EV::embeddable_backends
225
226Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
227instance of EV, the set of recommended backends (supposed to be good) for
228this platform and the set of embeddable backends (see EMBED WATCHERS).
229
230=item EV::sleep $seconds
231
232Block the process for the given number of (fractional) seconds.
233
146=item $time = EV::time 234=item $time = EV::time
147 235
148Returns the current time in (fractional) seconds since the epoch. 236Returns the current time in (fractional) seconds since the epoch.
149 237
150=item $time = EV::now 238=item $time = EV::now
151 239
152=item $time = $loop->now 240=item $time = $loop->now
153 241
154Returns the time the last event loop iteration has been started. This 242Returns the time the last event loop iteration has been started. This
155is the time that (relative) timers are based on, and refering to it is 243is the time that (relative) timers are based on, and referring to it is
156usually faster then calling EV::time. 244usually faster then calling EV::time.
157 245
246=item EV::now_update
247
248=item $loop->now_update
249
250Establishes the current time by querying the kernel, updating the time
251returned by C<EV::now> in the progress. This is a costly operation and
252is usually done automatically within C<EV::loop>.
253
254This function is rarely useful, but when some event callback runs for a
255very long time without entering the event loop, updating libev's idea of
256the current time is a good idea.
257
258=item EV::suspend
259
260=item $loop->suspend
261
262=item EV::resume
263
264=item $loop->resume
265
266These two functions suspend and resume a loop, for use when the loop is
267not used for a while and timeouts should not be processed.
268
269A typical use case would be an interactive program such as a game: When
270the user presses C<^Z> to suspend the game and resumes it an hour later it
271would be best to handle timeouts as if no time had actually passed while
272the program was suspended. This can be achieved by calling C<suspend>
273in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
274C<resume> directly afterwards to resume timer processing.
275
276Effectively, all C<timer> watchers will be delayed by the time spend
277between C<suspend> and C<resume>, and all C<periodic> watchers
278will be rescheduled (that is, they will lose any events that would have
279occured while suspended).
280
281After calling C<suspend> you B<must not> call I<any> function on the given
282loop other than C<resume>, and you B<must not> call C<resume>
283without a previous call to C<suspend>.
284
285Calling C<suspend>/C<resume> has the side effect of updating the event
286loop time (see C<now_update>).
287
158=item $backend = EV::backend 288=item $backend = EV::backend
159 289
160=item $backend = $loop->backend 290=item $backend = $loop->backend
161 291
162Returns an integer describing the backend used by libev (EV::METHOD_SELECT 292Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
163or EV::METHOD_EPOLL). 293or EV::BACKEND_EPOLL).
164 294
165=item EV::loop [$flags] 295=item EV::loop [$flags]
166 296
167=item $loop->loop ([$flags]) 297=item $loop->loop ([$flags])
168 298
188=item $count = EV::loop_count 318=item $count = EV::loop_count
189 319
190=item $count = $loop->loop_count 320=item $count = $loop->loop_count
191 321
192Return the number of times the event loop has polled for new 322Return the number of times the event loop has polled for new
193events. Sometiems useful as a generation counter. 323events. Sometimes useful as a generation counter.
194 324
195=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 325=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
196 326
197=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 327=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
198 328
209timeout. Otherwise a EV::timer with this value will be started. 339timeout. Otherwise a EV::timer with this value will be started.
210 340
211When 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
212the callback will be called with the received event set (in general 342the callback will be called with the received event set (in general
213you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>, 343you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
214C<EV::WRITE> and C<EV::TIMEOUT>). 344C<EV::WRITE> and C<EV::TIMER>).
215 345
216EV::once doesn't return anything: the watchers stay active till either 346EV::once doesn't return anything: the watchers stay active till either
217of 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
218invoked. 348invoked.
219 349
228=item EV::feed_signal_event ($signal) 358=item EV::feed_signal_event ($signal)
229 359
230Feed 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
231specified by C<$signal> had occured. 361specified by C<$signal> had occured.
232 362
363=item EV::set_io_collect_interval $time
364
365=item $loop->set_io_collect_interval ($time)
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
233=back 388=back
234 389
235 390
236=head1 WATCHER OBJECTS 391=head1 WATCHER OBJECTS
237 392
238A 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
239event. 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
240would create an EV::io watcher for that: 395would create an EV::io watcher for that:
241 396
242 my $watcher = EV::io *STDIN, EV::READ, sub { 397 my $watcher = EV::io *STDIN, EV::READ, sub {
243 my ($watcher, $revents) = @_; 398 my ($watcher, $revents) = @_;
244 warn "yeah, STDIN should now be readable without blocking!\n" 399 warn "yeah, STDIN should now be readable without blocking!\n"
245 }; 400 };
246 401
247All watchers can be active (waiting for events) or inactive (paused). Only 402All watchers can be active (waiting for events) or inactive (paused). Only
248active watchers will have their callbacks invoked. All callbacks will be 403active watchers will have their callbacks invoked. All callbacks will be
249called 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
250events. 405events.
251 406
252Each 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
253same callback for multiple watchers. The event mask is named after the 408same callback for multiple watchers. The event mask is named after the
254type, 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,
255EV::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
256(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).
257uses EV::TIMEOUT).
258 412
259In 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
260the 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
261its 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.
262 416
333Feed 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
334the watcher had received the given C<$revents> mask. 488the watcher had received the given C<$revents> mask.
335 489
336=item $revents = $w->clear_pending 490=item $revents = $w->clear_pending
337 491
338If the watcher is pending, this function returns clears its pending status 492If the watcher is pending, this function clears its pending status and
339and returns its C<$revents> bitset (as if its callback was invoked). If the 493returns its C<$revents> bitset (as if its callback was invoked). If the
340watcher isn't pending it does nothing and returns C<0>. 494watcher isn't pending it does nothing and returns C<0>.
341 495
342=item $previous_state = $w->keepalive ($bool) 496=item $previous_state = $w->keepalive ($bool)
343 497
344Normally, C<EV::loop> will return when there are no active watchers 498Normally, C<EV::loop> will return when there are no active watchers
345(which is a "deadlock" because no progress can be made anymore). This is 499(which is a "deadlock" because no progress can be made anymore). This is
346convinient because it allows you to start your watchers (and your jobs), 500convenient because it allows you to start your watchers (and your jobs),
347call C<EV::loop> once and when it returns you know that all your jobs are 501call C<EV::loop> once and when it returns you know that all your jobs are
348finished (or they forgot to register some watchers for their task :). 502finished (or they forgot to register some watchers for their task :).
349 503
350Sometimes, however, this gets in your way, for example when the module 504Sometimes, however, this gets in your way, for example when the module
351that calls C<EV::loop> (usually the main program) is not the same module 505that calls C<EV::loop> (usually the main program) is not the same module
355because you happen to have this long-running UDP port watcher. 509because you happen to have this long-running UDP port watcher.
356 510
357In 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
358though 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.
359 513
360The 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
361any time. 515any time.
362 516
363Example: 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
364event loop from running just because of that watcher. 518event loop from running just because of that watcher.
365 519
366 my $udp_socket = ... 520 my $udp_socket = ...
367 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 521 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
368 $1000udp_watcher->keepalive (0); 522 $udp_watcher->keepalive (0);
369 523
370=item $loop = $w->loop 524=item $loop = $w->loop
371 525
372Return the loop that this watcher is attached to. 526Return the loop that this watcher is attached to.
373 527
502This time simply fires at the wallclock time C<$at> and doesn't repeat. It 656This time simply fires at the wallclock time C<$at> and doesn't repeat. It
503will not adjust when a time jump occurs, that is, if it is to be run 657will not adjust when a time jump occurs, that is, if it is to be run
504at January 1st 2011 then it will run when the system time reaches or 658at January 1st 2011 then it will run when the system time reaches or
505surpasses this time. 659surpasses this time.
506 660
507=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 661=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
508 662
509In this mode the watcher will always be scheduled to time out at the 663In this mode the watcher will always be scheduled to time out at the
510next C<$at + N * $interval> time (for some integer N) and then repeat, 664next C<$at + N * $interval> time (for some integer N) and then repeat,
511regardless of any time jumps. 665regardless of any time jumps.
512 666
530time the periodic watcher gets scheduled, the reschedule callback 684time the periodic watcher gets scheduled, the reschedule callback
531($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
532time as second argument. 686time as second argument.
533 687
534I<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
535watcher, 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
536afterwards. 690you need to stop it, return 1e30 and stop it afterwards. You may create
691and start a C<EV::prepare> watcher for this task.
537 692
538It 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
539(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
540will usually be called just before the callback will be triggered, but 695argument). It will usually be called just before the callback will be
541might be called at other times, too. 696triggered, but might be called at other times, too.
542 697
543This 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
544triggers on each midnight, local time (actually 24 hours after the last 699triggers on each midnight, local time (actually 24 hours after the last
545midnight, 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
546in about the same space (without requiring elaborate modules), drop me a 701in about the same space (without requiring elaborate modules), drop me a
582 737
583=item $w = EV::signal $signal, $callback 738=item $w = EV::signal $signal, $callback
584 739
585=item $w = EV::signal_ns $signal, $callback 740=item $w = EV::signal_ns $signal, $callback
586 741
742=item $w = $loop->signal ($signal, $callback)
743
744=item $w = $loop->signal_ns ($signal, $callback)
745
587Call 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
588number 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.
589 752
590EV 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
591component 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,
592and 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
593add/remove callbacks to C<%SIG>, so watch out. 756add/remove callbacks to C<%SIG>, so watch out.
613 776
614=head3 CHILD WATCHERS - watch out for process status changes 777=head3 CHILD WATCHERS - watch out for process status changes
615 778
616=over 4 779=over 4
617 780
618=item $w = EV::child $pid, $callback 781=item $w = EV::child $pid, $trace, $callback
619 782
620=item $w = EV::child_ns $pid, $callback 783=item $w = EV::child_ns $pid, $trace, $callback
621 784
622=item $w = $loop->child ($pid, $callback) 785=item $w = $loop->child ($pid, $trace, $callback)
623 786
624=item $w = $loop->child_ns ($pid, $callback) 787=item $w = $loop->child_ns ($pid, $trace, $callback)
625 788
626Call the callback when a status change for pid C<$pid> (or any pid if 789Call the callback when a status change for pid C<$pid> (or any pid
627C<$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
628a 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
629changed/zombie children and call the callback. 794changed/zombie children and call the callback.
630 795
631It 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
632has 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
639You 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
640called. 805called.
641 806
642The 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.
643 808
644=item $w->set ($pid) 809=item $w->set ($pid, $trace)
645 810
646Reconfigures 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
647any time. 812any time.
648 813
649=item $current_pid = $w->pid 814=item $current_pid = $w->pid
650
651=item $old_pid = $w->pid ($new_pid)
652 815
653Returns the previously set process id and optionally set a new one. 816Returns the previously set process id and optionally set a new one.
654 817
655=item $exit_status = $w->rstatus 818=item $exit_status = $w->rstatus
656 819
818=item $w = $loop->check_ns ($callback) 981=item $w = $loop->check_ns ($callback)
819 982
820Call 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
821gathered events), but before any other callbacks have been invoked. 984gathered events), but before any other callbacks have been invoked.
822 985
823This is used to integrate other event-based software into the EV 986This can be used to integrate other event-based software into the EV
824mainloop: 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
825timer 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
826example of integrating Net::SNMP (with some details left out): 989example of integrating Net::SNMP (with some details left out):
827 990
828 our @snmp_watcher; 991 our @snmp_watcher;
858 # make the dispatcher handle any new stuff 1021 # make the dispatcher handle any new stuff
859 ... not shown 1022 ... not shown
860 }; 1023 };
861 1024
862The 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
863are destroyed before this cna happen (remember EV::check gets called 1026are destroyed before this can happen (remember EV::check gets called
864first). 1027first).
865 1028
866The 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.
867 1040
868=back 1041=back
869 1042
870 1043
871=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
886 1059
887Call 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
888after a fork. 1061after a fork.
889 1062
890The 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
891 1134
892=back 1135=back
893 1136
894 1137
895=head1 PERL SIGNALS 1138=head1 PERL SIGNALS
909 my $async_check = EV::check sub { }; 1152 my $async_check = EV::check sub { };
910 1153
911This 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
912pending signals, and also ensures (slightly) slower overall operation. 1155pending signals, and also ensures (slightly) slower overall operation.
913 1156
914=head1 THREADS 1157=head1 ITHREADS
915 1158
916Threads 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
917is 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
918on thread support for it. 1161supported (and enhanced support is available via L<Coro::EV>).
919 1162
920=head1 FORK 1163=head1 FORK
921 1164
922Most of the "improved" event delivering mechanisms of modern operating 1165Most of the "improved" event delivering mechanisms of modern operating
923systems 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
947 1190
948=head1 SEE ALSO 1191=head1 SEE ALSO
949 1192
950L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as 1193L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
951event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient 1194event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
952coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP). 1195coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1196event-loop agnostic and portable event driven programming.
953 1197
954=head1 AUTHOR 1198=head1 AUTHOR
955 1199
956 Marc Lehmann <schmorp@schmorp.de> 1200 Marc Lehmann <schmorp@schmorp.de>
957 http://home.schmorp.de/ 1201 http://home.schmorp.de/
958 1202
959=cut 1203=cut
960 1204

Diff Legend

Removed lines
+ Added lines
< Changed lines
> Changed lines