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Revision 1.96 by root, Thu May 22 02:44:57 2008 UTC vs.
Revision 1.137 by root, Sat Feb 4 20:12:17 2012 UTC

… …
2 2
3EV - perl interface to libev, a high performance full-featured event loop 3EV - perl interface to libev, a high performance full-featured event loop
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use EV; 7 use EV;
8
9 # TIMERS
10
11 my $w = EV::timer 2, 0, sub {
12 warn "is called after 2s";
13 };
14
15 my $w = EV::timer 2, 2, sub {
16 warn "is called roughly every 2s (repeat = 2)";
17 };
18
19 undef $w; # destroy event watcher again
20
21 my $w = EV::periodic 0, 60, 0, sub {
22 warn "is called every minute, on the minute, exactly";
23 };
24
25 # IO
26
27 my $w = EV::io *STDIN, EV::READ, sub {
28 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29 warn "stdin is readable, you entered: ", <STDIN>;
30 };
31
32 # SIGNALS
33
34 my $w = EV::signal 'QUIT', sub {
35 warn "sigquit received\n";
36 };
37
38 # CHILD/PID STATUS CHANGES
8 39
9 # TIMERS 40 my $w = EV::child 666, 0, sub {
41 my ($w, $revents) = @_;
42 my $status = $w->rstatus;
43 };
10 44
11 my $w = EV::timer 2, 0, sub {
12 warn "is called after 2s";
13 };
14
15 my $w = EV::timer 2, 2, sub {
16 warn "is called roughly every 2s (repeat = 2)";
17 };
18
19 undef $w; # destroy event watcher again
20
21 my $w = EV::periodic 0, 60, 0, sub {
22 warn "is called every minute, on the minute, exactly";
23 };
24
25 # IO
26
27 my $w = EV::io *STDIN, EV::READ, sub {
28 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29 warn "stdin is readable, you entered: ", <STDIN>;
30 };
31
32 # SIGNALS
33
34 my $w = EV::signal 'QUIT', sub {
35 warn "sigquit received\n";
36 };
37
38 # CHILD/PID STATUS CHANGES
39
40 my $w = EV::child 666, 0, sub {
41 my ($w, $revents) = @_;
42 my $status = $w->rstatus;
43 };
44
45 # STAT CHANGES 45 # STAT CHANGES
46 my $w = EV::stat "/etc/passwd", 10, sub { 46 my $w = EV::stat "/etc/passwd", 10, sub {
47 my ($w, $revents) = @_; 47 my ($w, $revents) = @_;
48 warn $w->path, " has changed somehow.\n"; 48 warn $w->path, " has changed somehow.\n";
49 }; 49 };
50 50
51 # MAINLOOP 51 # MAINLOOP
52 EV::loop; # loop until EV::unloop is called or all watchers stop 52 EV::run; # loop until EV::unloop is called or all watchers stop
53 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled 53 EV::run EV::RUN_ONCE; # block until at least one event could be handled
54 EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block 54 EV::run EV::RUN_NOWAIT; # try to handle same events, but do not block
55
56=head1 BEFORE YOU START USING THIS MODULE
57
58If you only need timer, I/O, signal, child and idle watchers and not the
59advanced functionality of this module, consider using L<AnyEvent> instead,
60specifically the simplified API described in L<AE>.
61
62When used with EV as backend, the L<AE> API is as fast as the native L<EV>
63API, but your programs/modules will still run with many other event loops.
55 64
56=head1 DESCRIPTION 65=head1 DESCRIPTION
57 66
58This module provides an interface to libev 67This module provides an interface to libev
59(L<http://software.schmorp.de/pkg/libev.html>). While the documentation 68(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
60below is comprehensive, one might also consult the documentation of libev 69below is comprehensive, one might also consult the documentation of
61itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>) for more 70libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
62subtle details on watcher semantics or some discussion on the available 71F<perldoc EV::libev>) for more subtle details on watcher semantics or some
63backends, or how to force a specific backend with C<LIBEV_FLAGS>, or just 72discussion on the available backends, or how to force a specific backend
64about in any case because it has much more detailed information. 73with C<LIBEV_FLAGS>, or just about in any case because it has much more
74detailed information.
65 75
66This module is very fast and scalable. It is actually so fast that you 76This module is very fast and scalable. It is actually so fast that you
67can use it through the L<AnyEvent> module, stay portable to other event 77can use it through the L<AnyEvent> module, stay portable to other event
68loops (if you don't rely on any watcher types not available through it) 78loops (if you don't rely on any watcher types not available through it)
69and still be faster than with any other event loop currently supported in 79and still be faster than with any other event loop currently supported in
70Perl. 80Perl.
71 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.
116
72=cut 117=cut
73 118
74package EV; 119package EV;
75 120
76use strict; 121use common::sense;
77 122
78BEGIN { 123BEGIN {
79 our $VERSION = '3.41'; 124 our $VERSION = '4.11';
80 use XSLoader; 125 use XSLoader;
81 XSLoader::load "EV", $VERSION; 126 XSLoader::load "EV", $VERSION;
82} 127}
83 128
84@EV::IO::ISA = 129@EV::IO::ISA =
… …
111default loop as this is fastest (perl-wise), best supported by other 156default loop as this is fastest (perl-wise), best supported by other
112modules (e.g. AnyEvent or Coro) and most portable event loop. 157modules (e.g. AnyEvent or Coro) and most portable event loop.
113 158
114For specific programs you can create additional event loops dynamically. 159For specific programs you can create additional event loops dynamically.
115 160
116=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.
117 166
167=over 4
168
118=item $loop = new EV::loop [$flags] 169=item $loop = new EV::Loop [$flags]
119 170
120Create 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
121C<ev_loop_new ()> function description in the libev documentation 172the C<ev_loop_new ()> function description in the libev documentation
122(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>,
123for more info. 174or locally-installed as F<EV::libev> manpage) for more info.
124 175
125The loop will automatically be destroyed when it is no longer referenced 176The loop will automatically be destroyed when it is no longer referenced
126by any watcher and the loop object goes out of scope. 177by any watcher and the loop object goes out of scope.
127 178
128Using 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>
129is 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.
130 183
131=item $loop->loop_fork 184=item $loop->loop_fork
132 185
133Must 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
134the 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
135this function automatically, at some performance loss (refer to the libev 188this function automatically, at some performance loss (refer to the libev
136documentation). 189documentation).
137 190
138=item $loop->loop_verify 191=item $loop->verify
139 192
140Calls C<ev_verify> to make internal consistency checks (for debugging 193Calls C<ev_verify> to make internal consistency checks (for debugging
141libev) and abort the program if any data structures wree found to be 194libev) and abort the program if any data structures were found to be
142corrupted. 195corrupted.
143 196
144=item $loop = EV::default_loop [$flags] 197=item $loop = EV::default_loop [$flags]
145 198
146Return the default loop (which is a singleton object). Since this module 199Return the default loop (which is a singleton object). Since this module
147already creates the default loop with default flags, specifying flags here 200already creates the default loop with default flags, specifying flags here
148will not have any effect unless you destroy the default loop. 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.
149 204
150=back 205=back
151 206
152 207
153=head1 BASIC INTERFACE 208=head1 BASIC INTERFACE
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183=item $time = EV::now 238=item $time = EV::now
184 239
185=item $time = $loop->now 240=item $time = $loop->now
186 241
187Returns the time the last event loop iteration has been started. This 242Returns the time the last event loop iteration has been started. This
188is 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
189usually faster then calling EV::time. 244usually faster then calling EV::time.
190 245
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
191=item $backend = EV::backend 288=item $backend = EV::backend
192 289
193=item $backend = $loop->backend 290=item $backend = $loop->backend
194 291
195Returns an integer describing the backend used by libev (EV::METHOD_SELECT 292Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
196or EV::METHOD_EPOLL). 293or EV::BACKEND_EPOLL).
197 294
198=item EV::loop [$flags] 295=item EV::run [$flags]
199 296
200=item $loop->loop ([$flags]) 297=item $loop->run ([$flags])
201 298
202Begin checking for events and calling callbacks. It returns when a 299Begin checking for events and calling callbacks. It returns when a
203callback calls EV::unloop. 300callback calls EV::unloop.
204 301
205The $flags argument can be one of the following: 302The $flags argument can be one of the following:
206 303
207 0 as above 304 0 as above
208 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 305 EV::RUN_ONCE block at most once (wait, but do not loop)
209 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 306 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
210 307
211=item EV::unloop [$how] 308=item EV::break [$how]
212 309
213=item $loop->unloop ([$how]) 310=item $loop->break ([$how])
214 311
215When called with no arguments or an argument of EV::UNLOOP_ONE, makes the 312When called with no arguments or an argument of EV::BREAK_ONE, makes the
216innermost call to EV::loop return. 313innermost call to EV::loop return.
217 314
218When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as 315When called with an argument of EV::BREAK_ALL, all calls to EV::loop will
219fast as possible. 316return as fast as possible.
220 317
221=item $count = EV::loop_count 318When called with an argument of EV::BREAK_CANCEL, any pending break will
319be cancelled.
222 320
321=item $count = EV::iteration
322
223=item $count = $loop->loop_count 323=item $count = $loop->iteration
224 324
225Return the number of times the event loop has polled for new 325Return the number of times the event loop has polled for new
226events. Sometiems useful as a generation counter. 326events. Sometimes useful as a generation counter.
227 327
228=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 328=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
229 329
230=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 330=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
231 331
… …
242timeout. Otherwise a EV::timer with this value will be started. 342timeout. Otherwise a EV::timer with this value will be started.
243 343
244When an error occurs or either the timeout or I/O watcher triggers, then 344When an error occurs or either the timeout or I/O watcher triggers, then
245the callback will be called with the received event set (in general 345the callback will be called with the received event set (in general
246you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>, 346you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
247C<EV::WRITE> and C<EV::TIMEOUT>). 347C<EV::WRITE> and C<EV::TIMER>).
248 348
249EV::once doesn't return anything: the watchers stay active till either 349EV::once doesn't return anything: the watchers stay active till either
250of them triggers, then they will be stopped and freed, and the callback 350of them triggers, then they will be stopped and freed, and the callback
251invoked. 351invoked.
252 352
253=item EV::feed_fd_event ($fd, $revents) 353=item EV::feed_fd_event $fd, $revents
254 354
255=item $loop->feed_fd_event ($fd, $revents) 355=item $loop->feed_fd_event ($fd, $revents)
256 356
257Feed an event on a file descriptor into EV. EV will react to this call as 357Feed an event on a file descriptor into EV. EV will react to this call as
258if the readyness notifications specified by C<$revents> (a combination of 358if the readyness notifications specified by C<$revents> (a combination of
259C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. 359C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
260 360
261=item EV::feed_signal_event ($signal) 361=item EV::feed_signal_event $signal
262 362
263Feed a signal event into EV. EV will react to this call as if the signal 363Feed a signal event into the default loop. EV will react to this call as
264specified by C<$signal> had occured. 364if the signal specified by C<$signal> had occured.
365
366=item EV::feed_signal $signal
367
368Feed a signal event into EV - unlike C<EV::feed_signal_event>, this works
369regardless of which loop has registered the signal, and is mainly useful
370fro custom signal implementations.
265 371
266=item EV::set_io_collect_interval $time 372=item EV::set_io_collect_interval $time
267 373
268=item $loop->set_io_collect_interval ($time) 374=item $loop->set_io_collect_interval ($time)
269 375
… …
271 377
272=item $loop->set_timeout_collect_interval ($time) 378=item $loop->set_timeout_collect_interval ($time)
273 379
274These advanced functions set the minimum block interval when polling for I/O events and the minimum 380These advanced functions set the minimum block interval when polling for I/O events and the minimum
275wait interval for timer events. See the libev documentation at 381wait interval for timer events. See the libev documentation at
276L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> for 382L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
277a more detailed discussion. 383(locally installed as F<EV::libev>) for a more detailed discussion.
384
385=item $count = EV::pending_count
386
387=item $count = $loop->pending_count
388
389Returns the number of currently pending watchers.
390
391=item EV::invoke_pending
392
393=item $loop->invoke_pending
394
395Invoke all currently pending watchers.
278 396
279=back 397=back
280 398
281 399
282=head1 WATCHER OBJECTS 400=head1 WATCHER OBJECTS
283 401
284A watcher is an object that gets created to record your interest in some 402A watcher is an object that gets created to record your interest in some
285event. For instance, if you want to wait for STDIN to become readable, you 403event. For instance, if you want to wait for STDIN to become readable, you
286would create an EV::io watcher for that: 404would create an EV::io watcher for that:
287 405
288 my $watcher = EV::io *STDIN, EV::READ, sub { 406 my $watcher = EV::io *STDIN, EV::READ, sub {
289 my ($watcher, $revents) = @_; 407 my ($watcher, $revents) = @_;
290 warn "yeah, STDIN should now be readable without blocking!\n" 408 warn "yeah, STDIN should now be readable without blocking!\n"
291 }; 409 };
292 410
293All watchers can be active (waiting for events) or inactive (paused). Only 411All watchers can be active (waiting for events) or inactive (paused). Only
294active watchers will have their callbacks invoked. All callbacks will be 412active watchers will have their callbacks invoked. All callbacks will be
295called with at least two arguments: the watcher and a bitmask of received 413called with at least two arguments: the watcher and a bitmask of received
296events. 414events.
297 415
298Each watcher type has its associated bit in revents, so you can use the 416Each watcher type has its associated bit in revents, so you can use the
299same callback for multiple watchers. The event mask is named after the 417same callback for multiple watchers. The event mask is named after the
300type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 418type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
301EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events 419EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
302(which can set both EV::READ and EV::WRITE bits), and EV::timer (which 420(which can set both EV::READ and EV::WRITE bits).
303uses EV::TIMEOUT).
304 421
305In the rare case where one wants to create a watcher but not start it at 422In the rare case where one wants to create a watcher but not start it at
306the same time, each constructor has a variant with a trailing C<_ns> in 423the same time, each constructor has a variant with a trailing C<_ns> in
307its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. 424its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
308 425
… …
387 504
388=item $previous_state = $w->keepalive ($bool) 505=item $previous_state = $w->keepalive ($bool)
389 506
390Normally, C<EV::loop> will return when there are no active watchers 507Normally, C<EV::loop> will return when there are no active watchers
391(which is a "deadlock" because no progress can be made anymore). This is 508(which is a "deadlock" because no progress can be made anymore). This is
392convinient because it allows you to start your watchers (and your jobs), 509convenient because it allows you to start your watchers (and your jobs),
393call C<EV::loop> once and when it returns you know that all your jobs are 510call C<EV::loop> once and when it returns you know that all your jobs are
394finished (or they forgot to register some watchers for their task :). 511finished (or they forgot to register some watchers for their task :).
395 512
396Sometimes, however, this gets in your way, for example when the module 513Sometimes, however, this gets in your way, for example when the module
397that calls C<EV::loop> (usually the main program) is not the same module 514that calls C<EV::loop> (usually the main program) is not the same module
… …
401because you happen to have this long-running UDP port watcher. 518because you happen to have this long-running UDP port watcher.
402 519
403In this case you can clear the keepalive status, which means that even 520In this case you can clear the keepalive status, which means that even
404though your watcher is active, it won't keep C<EV::loop> from returning. 521though your watcher is active, it won't keep C<EV::loop> from returning.
405 522
406The initial value for keepalive is true (enabled), and you cna change it 523The initial value for keepalive is true (enabled), and you can change it
407any time. 524any time.
408 525
409Example: Register an I/O watcher for some UDP socket but do not keep the 526Example: Register an I/O watcher for some UDP socket but do not keep the
410event loop from running just because of that watcher. 527event loop from running just because of that watcher.
411 528
412 my $udp_socket = ... 529 my $udp_socket = ...
413 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 530 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
414 $1000udp_watcher->keepalive (0); 531 $udp_watcher->keepalive (0);
415 532
416=item $loop = $w->loop 533=item $loop = $w->loop
417 534
418Return the loop that this watcher is attached to. 535Return the loop that this watcher is attached to.
419 536
… …
629 746
630=item $w = EV::signal $signal, $callback 747=item $w = EV::signal $signal, $callback
631 748
632=item $w = EV::signal_ns $signal, $callback 749=item $w = EV::signal_ns $signal, $callback
633 750
751=item $w = $loop->signal ($signal, $callback)
752
753=item $w = $loop->signal_ns ($signal, $callback)
754
634Call the callback when $signal is received (the signal can be specified by 755Call the callback when $signal is received (the signal can be specified by
635number or by name, just as with C<kill> or C<%SIG>). 756number or by name, just as with C<kill> or C<%SIG>).
757
758Only one event loop can grab a given signal - attempting to grab the same
759signal from two EV loops will crash the program immediately or cause data
760corruption.
636 761
637EV will grab the signal for the process (the kernel only allows one 762EV will grab the signal for the process (the kernel only allows one
638component to receive a signal at a time) when you start a signal watcher, 763component to receive a signal at a time) when you start a signal watcher,
639and removes it again when you stop it. Perl does the same when you 764and removes it again when you stop it. Perl does the same when you
640add/remove callbacks to C<%SIG>, so watch out. 765add/remove callbacks to C<%SIG>, so watch out.
… …
865=item $w = $loop->check_ns ($callback) 990=item $w = $loop->check_ns ($callback)
866 991
867Call the callback just after the process wakes up again (after it has 992Call the callback just after the process wakes up again (after it has
868gathered events), but before any other callbacks have been invoked. 993gathered events), but before any other callbacks have been invoked.
869 994
870This is used to integrate other event-based software into the EV 995This can be used to integrate other event-based software into the EV
871mainloop: You register a prepare callback and in there, you create io and 996mainloop: You register a prepare callback and in there, you create io and
872timer watchers as required by the other software. Here is a real-world 997timer watchers as required by the other software. Here is a real-world
873example of integrating Net::SNMP (with some details left out): 998example of integrating Net::SNMP (with some details left out):
874 999
875 our @snmp_watcher; 1000 our @snmp_watcher;
… …
905 # make the dispatcher handle any new stuff 1030 # make the dispatcher handle any new stuff
906 ... not shown 1031 ... not shown
907 }; 1032 };
908 1033
909The callbacks of the created watchers will not be called as the watchers 1034The callbacks of the created watchers will not be called as the watchers
910are destroyed before this cna happen (remember EV::check gets called 1035are destroyed before this can happen (remember EV::check gets called
911first). 1036first).
912 1037
913The C<check_ns> variant doesn't start (activate) the newly created watcher. 1038The C<check_ns> variant doesn't start (activate) the newly created watcher.
1039
1040=item EV::CHECK constant issues
1041
1042Like all other watcher types, there is a bitmask constant for use in
1043C<$revents> and other places. The C<EV::CHECK> is special as it has
1044the same name as the C<CHECK> sub called by Perl. This doesn't cause
1045big issues on newer perls (beginning with 5.8.9), but it means thatthe
1046constant must be I<inlined>, i.e. runtime calls will not work. That means
1047that as long as you always C<use EV> and then C<EV::CHECK> you are on the
1048safe side.
914 1049
915=back 1050=back
916 1051
917 1052
918=head3 FORK WATCHERS - the audacity to resume the event loop after a fork 1053=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
… …
946loop, other types of watchers might be handled in a delayed or incorrect 1081loop, other types of watchers might be handled in a delayed or incorrect
947fashion and must not be used). 1082fashion and must not be used).
948 1083
949See the libev documentation at 1084See the libev documentation at
950L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> 1085L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
951for more details. 1086(locally installed as F<EV::libev>) for more details.
952 1087
953In short, this watcher is most useful on BSD systems without working 1088In short, this watcher is most useful on BSD systems without working
954kqueue to still be able to handle a large number of sockets: 1089kqueue to still be able to handle a large number of sockets:
955 1090
956 my $socket_loop; 1091 my $socket_loop;
957 1092
958 # check wether we use SELECT or POLL _and_ KQUEUE is supported 1093 # check wether we use SELECT or POLL _and_ KQUEUE is supported
959 if ( 1094 if (
960 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 1095 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
961 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 1096 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
962 ) { 1097 ) {
963 # use kqueue for sockets 1098 # use kqueue for sockets
964 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 1099 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
965 } 1100 }
966 1101
967 # use the default loop otherwise 1102 # use the default loop otherwise
968 $socket_loop ||= EV::default_loop; 1103 $socket_loop ||= EV::default_loop;
969 1104
970=over 4 1105=over 4
971 1106
972=item $w = EV::embed $otherloop, $callback 1107=item $w = EV::embed $otherloop[, $callback]
973 1108
974=item $w = EV::embed_ns $otherloop, $callback 1109=item $w = EV::embed_ns $otherloop[, $callback]
975 1110
976=item $w = $loop->embed ($otherloop, $callback) 1111=item $w = $loop->embed ($otherloop[, $callback])
977 1112
978=item $w = $loop->embed_ns ($otherloop, $callback) 1113=item $w = $loop->embed_ns ($otherloop[, $callback])
979 1114
980Call the callback when the embedded event loop (C<$otherloop>) has any 1115Call the callback when the embedded event loop (C<$otherloop>) has any
981I/O activity. The C<$callback> should alwas be specified as C<undef> in 1116I/O activity. The C<$callback> is optional: if it is missing, then the
982this version of EV, which means the embedded event loop will be managed 1117embedded event loop will be managed automatically (which is recommended),
983automatically. 1118otherwise you have to invoke C<sweep> yourself.
984 1119
985The C<embed_ns> variant doesn't start (activate) the newly created watcher. 1120The C<embed_ns> variant doesn't start (activate) the newly created watcher.
986 1121
987=back 1122=back
988 1123
989=head3 ASYNC WATCHERS - how to wake up another event loop 1124=head3 ASYNC WATCHERS - how to wake up another event loop
990 1125
991Async watchers are provided by EV, but have little use in perl directly, as perl 1126Async watchers are provided by EV, but have little use in perl directly,
992neither supports threads nor direct access to signal handlers or other 1127as perl neither supports threads running in parallel nor direct access to
993contexts where they could be of value. 1128signal handlers or other contexts where they could be of value.
994 1129
995It is, however, possible to use them from the XS level. 1130It is, however, possible to use them from the XS level.
996 1131
997Please see the libev documentation for further details. 1132Please see the libev documentation for further details.
998 1133
… …
1026 my $async_check = EV::check sub { }; 1161 my $async_check = EV::check sub { };
1027 1162
1028This ensures that perl gets into control for a short time to handle any 1163This ensures that perl gets into control for a short time to handle any
1029pending signals, and also ensures (slightly) slower overall operation. 1164pending signals, and also ensures (slightly) slower overall operation.
1030 1165
1031=head1 THREADS 1166=head1 ITHREADS
1032 1167
1033Threads are not supported by this module in any way. Perl pseudo-threads 1168Ithreads are not supported by this module in any way. Perl pseudo-threads
1034is evil stuff and must die. As soon as Perl gains real threads I will work 1169is evil stuff and must die. Real threads as provided by Coro are fully
1035on thread support for it. 1170supported (and enhanced support is available via L<Coro::EV>).
1036 1171
1037=head1 FORK 1172=head1 FORK
1038 1173
1039Most of the "improved" event delivering mechanisms of modern operating 1174Most of the "improved" event delivering mechanisms of modern operating
1040systems have quite a few problems with fork(2) (to put it bluntly: it is 1175systems have quite a few problems with fork(2) (to put it bluntly: it is
… …
1062 1197
10631; 11981;
1064 1199
1065=head1 SEE ALSO 1200=head1 SEE ALSO
1066 1201
1202L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS>
1067L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as 1203(asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as event
1068event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient 1204loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient thread
1069coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for 1205integration), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1070event-loop agnostic and portable event driven programming. 1206event-loop agnostic and portable event driven programming.
1071 1207
1072=head1 AUTHOR 1208=head1 AUTHOR
1073 1209
1074 Marc Lehmann <schmorp@schmorp.de> 1210 Marc Lehmann <schmorp@schmorp.de>
1075 http://home.schmorp.de/ 1211 http://home.schmorp.de/
1076 1212
1077=cut 1213=cut
1078 1214

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