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Revision 1.70 by root, Fri Dec 14 19:33:32 2007 UTC vs.
Revision 1.127 by root, Sun Mar 28 15:48:21 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 MODULE EXPORTS
83
84This module does not export any symbols.
65 85
66=cut 86=cut
67 87
68package EV; 88package EV;
69 89
70use strict; 90use common::sense;
71 91
72BEGIN { 92BEGIN {
73 our $VERSION = '1.85'; 93 our $VERSION = '4.00';
74 use XSLoader; 94 use XSLoader;
75 XSLoader::load "EV", $VERSION; 95 XSLoader::load "EV", $VERSION;
76} 96}
77 97
78@EV::IO::ISA = 98@EV::IO::ISA =
… …
84@EV::Idle::ISA = 104@EV::Idle::ISA =
85@EV::Prepare::ISA = 105@EV::Prepare::ISA =
86@EV::Check::ISA = 106@EV::Check::ISA =
87@EV::Embed::ISA = 107@EV::Embed::ISA =
88@EV::Fork::ISA = 108@EV::Fork::ISA =
109@EV::Async::ISA =
89 "EV::Watcher"; 110 "EV::Watcher";
111
112@EV::Loop::Default::ISA = "EV::Loop";
113
114=head1 EVENT LOOPS
115
116EV supports multiple event loops: There is a single "default event loop"
117that can handle everything including signals and child watchers, and any
118number of "dynamic event loops" that can use different backends (with
119various limitations), but no child and signal watchers.
120
121You do not have to do anything to create the default event loop: When
122the module is loaded a suitable backend is selected on the premise of
123selecting a working backend (which for example rules out kqueue on most
124BSDs). Modules should, unless they have "special needs" always use the
125default loop as this is fastest (perl-wise), best supported by other
126modules (e.g. AnyEvent or Coro) and most portable event loop.
127
128For specific programs you can create additional event loops dynamically.
129
130If you want to take advantage of kqueue (which often works properly for
131sockets only) even though the default loop doesn't enable it, you can
132I<embed> a kqueue loop into the default loop: running the default loop
133will then also service the kqueue loop to some extent. See the example in
134the section about embed watchers for an example on how to achieve that.
135
136=over 4
137
138=item $loop = new EV::Loop [$flags]
139
140Create a new event loop as per the specified flags. Please refer to
141the C<ev_loop_new ()> function description in the libev documentation
142(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
143or locally-installed as F<EV::libev> manpage) for more info.
144
145The loop will automatically be destroyed when it is no longer referenced
146by any watcher and the loop object goes out of scope.
147
148If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
149is recommended, as only the default event loop is protected by this
150module. If you I<are> embedding this loop in the default loop, this is not
151necessary, as C<EV::embed> automatically does the right thing on fork.
152
153=item $loop->loop_fork
154
155Must be called after a fork in the child, before entering or continuing
156the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
157this function automatically, at some performance loss (refer to the libev
158documentation).
159
160=item $loop->loop_verify
161
162Calls C<ev_verify> to make internal consistency checks (for debugging
163libev) and abort the program if any data structures were found to be
164corrupted.
165
166=item $loop = EV::default_loop [$flags]
167
168Return the default loop (which is a singleton object). Since this module
169already creates the default loop with default flags, specifying flags here
170will not have any effect unless you destroy the default loop first, which
171isn't supported. So in short: don't do it, and if you break it, you get to
172keep the pieces.
173
174=back
175
90 176
91=head1 BASIC INTERFACE 177=head1 BASIC INTERFACE
92 178
93=over 4 179=over 4
94 180
… …
98throws an exception (with $@ containing the error). The default prints an 184throws an exception (with $@ containing the error). The default prints an
99informative message and continues. 185informative message and continues.
100 186
101If this callback throws an exception it will be silently ignored. 187If this callback throws an exception it will be silently ignored.
102 188
189=item $flags = EV::supported_backends
190
191=item $flags = EV::recommended_backends
192
193=item $flags = EV::embeddable_backends
194
195Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
196instance of EV, the set of recommended backends (supposed to be good) for
197this platform and the set of embeddable backends (see EMBED WATCHERS).
198
199=item EV::sleep $seconds
200
201Block the process for the given number of (fractional) seconds.
202
103=item $time = EV::time 203=item $time = EV::time
104 204
105Returns the current time in (fractional) seconds since the epoch. 205Returns the current time in (fractional) seconds since the epoch.
106 206
107=item $time = EV::now 207=item $time = EV::now
108 208
209=item $time = $loop->now
210
109Returns the time the last event loop iteration has been started. This 211Returns the time the last event loop iteration has been started. This
110is the time that (relative) timers are based on, and refering to it is 212is the time that (relative) timers are based on, and referring to it is
111usually faster then calling EV::time. 213usually faster then calling EV::time.
112 214
113=item $method = EV::method 215=item EV::now_update
114 216
217=item $loop->now_update
218
219Establishes the current time by querying the kernel, updating the time
220returned by C<EV::now> in the progress. This is a costly operation and
221is usually done automatically within C<EV::loop>.
222
223This function is rarely useful, but when some event callback runs for a
224very long time without entering the event loop, updating libev's idea of
225the current time is a good idea.
226
227=item EV::suspend
228
229=item $loop->suspend
230
231=item EV::resume
232
233=item $loop->resume
234
235These two functions suspend and resume a loop, for use when the loop is
236not used for a while and timeouts should not be processed.
237
238A typical use case would be an interactive program such as a game: When
239the user presses C<^Z> to suspend the game and resumes it an hour later it
240would be best to handle timeouts as if no time had actually passed while
241the program was suspended. This can be achieved by calling C<suspend>
242in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
243C<resume> directly afterwards to resume timer processing.
244
245Effectively, all C<timer> watchers will be delayed by the time spend
246between C<suspend> and C<resume>, and all C<periodic> watchers
247will be rescheduled (that is, they will lose any events that would have
248occured while suspended).
249
250After calling C<suspend> you B<must not> call I<any> function on the given
251loop other than C<resume>, and you B<must not> call C<resume>
252without a previous call to C<suspend>.
253
254Calling C<suspend>/C<resume> has the side effect of updating the event
255loop time (see C<now_update>).
256
257=item $backend = EV::backend
258
259=item $backend = $loop->backend
260
115Returns an integer describing the backend used by libev (EV::METHOD_SELECT 261Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
116or EV::METHOD_EPOLL). 262or EV::BACKEND_EPOLL).
117 263
118=item EV::loop [$flags] 264=item EV::loop [$flags]
265
266=item $loop->loop ([$flags])
119 267
120Begin checking for events and calling callbacks. It returns when a 268Begin checking for events and calling callbacks. It returns when a
121callback calls EV::unloop. 269callback calls EV::unloop.
122 270
123The $flags argument can be one of the following: 271The $flags argument can be one of the following:
… …
126 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 274 EV::LOOP_ONESHOT block at most once (wait, but do not loop)
127 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 275 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
128 276
129=item EV::unloop [$how] 277=item EV::unloop [$how]
130 278
279=item $loop->unloop ([$how])
280
131When called with no arguments or an argument of EV::UNLOOP_ONE, makes the 281When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
132innermost call to EV::loop return. 282innermost call to EV::loop return.
133 283
134When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as 284When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
135fast as possible. 285fast as possible.
136 286
137=item $count = EV::loop_count 287=item $count = EV::loop_count
138 288
289=item $count = $loop->loop_count
290
139Return the number of times the event loop has polled for new 291Return the number of times the event loop has polled for new
140events. Sometiems useful as a generation counter. 292events. Sometimes useful as a generation counter.
141 293
142=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 294=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
295
296=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
143 297
144This function rolls together an I/O and a timer watcher for a single 298This function rolls together an I/O and a timer watcher for a single
145one-shot event without the need for managing a watcher object. 299one-shot event without the need for managing a watcher object.
146 300
147If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> 301If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
… …
153If timeout is C<undef> or negative, then there will be no 307If timeout is C<undef> or negative, then there will be no
154timeout. Otherwise a EV::timer with this value will be started. 308timeout. Otherwise a EV::timer with this value will be started.
155 309
156When an error occurs or either the timeout or I/O watcher triggers, then 310When an error occurs or either the timeout or I/O watcher triggers, then
157the callback will be called with the received event set (in general 311the callback will be called with the received event set (in general
158you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>, 312you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
159C<EV::WRITE> and C<EV::TIMEOUT>). 313C<EV::WRITE> and C<EV::TIMER>).
160 314
161EV::once doesn't return anything: the watchers stay active till either 315EV::once doesn't return anything: the watchers stay active till either
162of them triggers, then they will be stopped and freed, and the callback 316of them triggers, then they will be stopped and freed, and the callback
163invoked. 317invoked.
164 318
165=item EV::feed_fd_event ($fd, $revents) 319=item EV::feed_fd_event ($fd, $revents)
166 320
321=item $loop->feed_fd_event ($fd, $revents)
322
167Feed an event on a file descriptor into EV. EV will react to this call as 323Feed an event on a file descriptor into EV. EV will react to this call as
168if the readyness notifications specified by C<$revents> (a combination of 324if the readyness notifications specified by C<$revents> (a combination of
169C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. 325C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
170 326
171=item EV::feed_signal_event ($signal) 327=item EV::feed_signal_event ($signal)
172 328
173Feed a signal event into EV. EV will react to this call as if the signal 329Feed a signal event into EV. EV will react to this call as if the signal
174specified by C<$signal> had occured. 330specified by C<$signal> had occured.
175 331
176=back 332=item EV::set_io_collect_interval $time
177 333
334=item $loop->set_io_collect_interval ($time)
178 335
336=item EV::set_timeout_collect_interval $time
337
338=item $loop->set_timeout_collect_interval ($time)
339
340These advanced functions set the minimum block interval when polling for I/O events and the minimum
341wait interval for timer events. See the libev documentation at
342L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
343(locally installed as F<EV::libev>) for a more detailed discussion.
344
345=item $count = EV::pending_count
346
347=item $count = $loop->pending_count
348
349Returns the number of currently pending watchers.
350
351=item EV::invoke_pending
352
353=item $loop->invoke_pending
354
355Invoke all currently pending watchers.
356
357=back
358
359
179=head2 WATCHER OBJECTS 360=head1 WATCHER OBJECTS
180 361
181A watcher is an object that gets created to record your interest in some 362A watcher is an object that gets created to record your interest in some
182event. For instance, if you want to wait for STDIN to become readable, you 363event. For instance, if you want to wait for STDIN to become readable, you
183would create an EV::io watcher for that: 364would create an EV::io watcher for that:
184 365
185 my $watcher = EV::io *STDIN, EV::READ, sub { 366 my $watcher = EV::io *STDIN, EV::READ, sub {
186 my ($watcher, $revents) = @_; 367 my ($watcher, $revents) = @_;
187 warn "yeah, STDIN should not be readable without blocking!\n" 368 warn "yeah, STDIN should now be readable without blocking!\n"
188 }; 369 };
189 370
190All watchers can be active (waiting for events) or inactive (paused). Only 371All watchers can be active (waiting for events) or inactive (paused). Only
191active watchers will have their callbacks invoked. All callbacks will be 372active watchers will have their callbacks invoked. All callbacks will be
192called with at least two arguments: the watcher and a bitmask of received 373called with at least two arguments: the watcher and a bitmask of received
193events. 374events.
194 375
195Each watcher type has its associated bit in revents, so you can use the 376Each watcher type has its associated bit in revents, so you can use the
196same callback for multiple watchers. The event mask is named after the 377same callback for multiple watchers. The event mask is named after the
197type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 378type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
198EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events 379EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
199(which can set both EV::READ and EV::WRITE bits), and EV::timer (which 380(which can set both EV::READ and EV::WRITE bits).
200uses EV::TIMEOUT).
201 381
202In the rare case where one wants to create a watcher but not start it at 382In the rare case where one wants to create a watcher but not start it at
203the same time, each constructor has a variant with a trailing C<_ns> in 383the same time, each constructor has a variant with a trailing C<_ns> in
204its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. 384its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
205 385
… …
276Feed some events on this watcher into EV. EV will react to this call as if 456Feed some events on this watcher into EV. EV will react to this call as if
277the watcher had received the given C<$revents> mask. 457the watcher had received the given C<$revents> mask.
278 458
279=item $revents = $w->clear_pending 459=item $revents = $w->clear_pending
280 460
281If the watcher is pending, this function returns clears its pending status 461If the watcher is pending, this function clears its pending status and
282and returns its C<$revents> bitset (as if its callback was invoked). If the 462returns its C<$revents> bitset (as if its callback was invoked). If the
283watcher isn't pending it does nothing and returns C<0>. 463watcher isn't pending it does nothing and returns C<0>.
284 464
285=item $previous_state = $w->keepalive ($bool) 465=item $previous_state = $w->keepalive ($bool)
286 466
287Normally, C<EV::loop> will return when there are no active watchers 467Normally, C<EV::loop> will return when there are no active watchers
288(which is a "deadlock" because no progress can be made anymore). This is 468(which is a "deadlock" because no progress can be made anymore). This is
289convinient because it allows you to start your watchers (and your jobs), 469convenient because it allows you to start your watchers (and your jobs),
290call C<EV::loop> once and when it returns you know that all your jobs are 470call C<EV::loop> once and when it returns you know that all your jobs are
291finished (or they forgot to register some watchers for their task :). 471finished (or they forgot to register some watchers for their task :).
292 472
293Sometimes, however, this gets in your way, for example when you the module 473Sometimes, however, this gets in your way, for example when the module
294that calls C<EV::loop> (usually the main program) is not the same module 474that calls C<EV::loop> (usually the main program) is not the same module
295as a long-living watcher (for example a DNS client module written by 475as a long-living watcher (for example a DNS client module written by
296somebody else even). Then you might want any outstanding requests to be 476somebody else even). Then you might want any outstanding requests to be
297handled, but you would not want to keep C<EV::loop> from returning just 477handled, but you would not want to keep C<EV::loop> from returning just
298because you happen to have this long-running UDP port watcher. 478because you happen to have this long-running UDP port watcher.
299 479
300In this case you can clear the keepalive status, which means that even 480In this case you can clear the keepalive status, which means that even
301though your watcher is active, it won't keep C<EV::loop> from returning. 481though your watcher is active, it won't keep C<EV::loop> from returning.
302 482
303The initial value for keepalive is true (enabled), and you cna change it 483The initial value for keepalive is true (enabled), and you can change it
304any time. 484any time.
305 485
306Example: Register an I/O watcher for some UDP socket but do not keep the 486Example: Register an I/O watcher for some UDP socket but do not keep the
307event loop from running just because of that watcher. 487event loop from running just because of that watcher.
308 488
309 my $udp_socket = ... 489 my $udp_socket = ...
310 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 490 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
311 $udp_watcher->keepalive (0); 491 $udp_watcher->keepalive (0);
312 492
313=back 493=item $loop = $w->loop
314 494
495Return the loop that this watcher is attached to.
315 496
497=back
498
499
316=head2 WATCHER TYPES 500=head1 WATCHER TYPES
317 501
318Each of the following subsections describes a single watcher type. 502Each of the following subsections describes a single watcher type.
319 503
320=head3 I/O WATCHERS - is this file descriptor readable or writable? 504=head3 I/O WATCHERS - is this file descriptor readable or writable?
321 505
322=over 4 506=over 4
323 507
324=item $w = EV::io $fileno_or_fh, $eventmask, $callback 508=item $w = EV::io $fileno_or_fh, $eventmask, $callback
325 509
326=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 510=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
511
512=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
513
514=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
327 515
328As long as the returned watcher object is alive, call the C<$callback> 516As long as the returned watcher object is alive, call the C<$callback>
329when at least one of events specified in C<$eventmask> occurs. 517when at least one of events specified in C<$eventmask> occurs.
330 518
331The $eventmask can be one or more of these constants ORed together: 519The $eventmask can be one or more of these constants ORed together:
… …
360=over 4 548=over 4
361 549
362=item $w = EV::timer $after, $repeat, $callback 550=item $w = EV::timer $after, $repeat, $callback
363 551
364=item $w = EV::timer_ns $after, $repeat, $callback 552=item $w = EV::timer_ns $after, $repeat, $callback
553
554=item $w = $loop->timer ($after, $repeat, $callback)
555
556=item $w = $loop->timer_ns ($after, $repeat, $callback)
365 557
366Calls the callback after C<$after> seconds (which may be fractional). If 558Calls the callback after C<$after> seconds (which may be fractional). If
367C<$repeat> is non-zero, the timer will be restarted (with the $repeat 559C<$repeat> is non-zero, the timer will be restarted (with the $repeat
368value as $after) after the callback returns. 560value as $after) after the callback returns.
369 561
… …
410=over 4 602=over 4
411 603
412=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback 604=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
413 605
414=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 606=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
607
608=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
609
610=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
415 611
416Similar to EV::timer, but is not based on relative timeouts but on 612Similar to EV::timer, but is not based on relative timeouts but on
417absolute times. Apart from creating "simple" timers that trigger "at" the 613absolute times. Apart from creating "simple" timers that trigger "at" the
418specified time, it can also be used for non-drifting absolute timers and 614specified time, it can also be used for non-drifting absolute timers and
419more complex, cron-like, setups that are not adversely affected by time 615more complex, cron-like, setups that are not adversely affected by time
… …
429This time simply fires at the wallclock time C<$at> and doesn't repeat. It 625This time simply fires at the wallclock time C<$at> and doesn't repeat. It
430will not adjust when a time jump occurs, that is, if it is to be run 626will not adjust when a time jump occurs, that is, if it is to be run
431at January 1st 2011 then it will run when the system time reaches or 627at January 1st 2011 then it will run when the system time reaches or
432surpasses this time. 628surpasses this time.
433 629
434=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 630=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
435 631
436In this mode the watcher will always be scheduled to time out at the 632In this mode the watcher will always be scheduled to time out at the
437next C<$at + N * $interval> time (for some integer N) and then repeat, 633next C<$at + N * $interval> time (for some integer N) and then repeat,
438regardless of any time jumps. 634regardless of any time jumps.
439 635
… …
457time the periodic watcher gets scheduled, the reschedule callback 653time the periodic watcher gets scheduled, the reschedule callback
458($reschedule_cb) will be called with the watcher as first, and the current 654($reschedule_cb) will be called with the watcher as first, and the current
459time as second argument. 655time as second argument.
460 656
461I<This callback MUST NOT stop or destroy this or any other periodic 657I<This callback MUST NOT stop or destroy this or any other periodic
462watcher, ever>. If you need to stop it, return 1e30 and stop it 658watcher, ever, and MUST NOT call any event loop functions or methods>. If
463afterwards. 659you need to stop it, return 1e30 and stop it afterwards. You may create
660and start a C<EV::prepare> watcher for this task.
464 661
465It must return the next time to trigger, based on the passed time value 662It must return the next time to trigger, based on the passed time value
466(that is, the lowest time value larger than to the second argument). It 663(that is, the lowest time value larger than or equal to to the second
467will usually be called just before the callback will be triggered, but 664argument). It will usually be called just before the callback will be
468might be called at other times, too. 665triggered, but might be called at other times, too.
469 666
470This can be used to create very complex timers, such as a timer that 667This can be used to create very complex timers, such as a timer that
471triggers on each midnight, local time (actually 24 hours after the last 668triggers on each midnight, local time (actually 24 hours after the last
472midnight, to keep the example simple. If you know a way to do it correctly 669midnight, to keep the example simple. If you know a way to do it correctly
473in about the same space (without requiring elaborate modules), drop me a 670in about the same space (without requiring elaborate modules), drop me a
… …
494 691
495=item $w->again 692=item $w->again
496 693
497Simply stops and starts the watcher again. 694Simply stops and starts the watcher again.
498 695
696=item $time = $w->at
697
698Return the time that the watcher is expected to trigger next.
699
499=back 700=back
500 701
501 702
502=head3 SIGNAL WATCHERS - signal me when a signal gets signalled! 703=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
503 704
504=over 4 705=over 4
505 706
506=item $w = EV::signal $signal, $callback 707=item $w = EV::signal $signal, $callback
507 708
508=item $w = EV::signal_ns $signal, $callback 709=item $w = EV::signal_ns $signal, $callback
710
711=item $w = $loop->signal ($signal, $callback)
712
713=item $w = $loop->signal_ns ($signal, $callback)
509 714
510Call the callback when $signal is received (the signal can be specified by 715Call the callback when $signal is received (the signal can be specified by
511number or by name, just as with C<kill> or C<%SIG>). 716number or by name, just as with C<kill> or C<%SIG>).
717
718Only one event loop can grab a given signal - attempting to grab the same
719signal from two EV loops will crash the program immediately or cause data
720corruption.
512 721
513EV will grab the signal for the process (the kernel only allows one 722EV will grab the signal for the process (the kernel only allows one
514component to receive a signal at a time) when you start a signal watcher, 723component to receive a signal at a time) when you start a signal watcher,
515and removes it again when you stop it. Perl does the same when you 724and removes it again when you stop it. Perl does the same when you
516add/remove callbacks to C<%SIG>, so watch out. 725add/remove callbacks to C<%SIG>, so watch out.
… …
536 745
537=head3 CHILD WATCHERS - watch out for process status changes 746=head3 CHILD WATCHERS - watch out for process status changes
538 747
539=over 4 748=over 4
540 749
541=item $w = EV::child $pid, $callback 750=item $w = EV::child $pid, $trace, $callback
542 751
543=item $w = EV::child_ns $pid, $callback 752=item $w = EV::child_ns $pid, $trace, $callback
544 753
754=item $w = $loop->child ($pid, $trace, $callback)
755
756=item $w = $loop->child_ns ($pid, $trace, $callback)
757
545Call the callback when a status change for pid C<$pid> (or any pid if 758Call the callback when a status change for pid C<$pid> (or any pid
546C<$pid> is 0) has been received. More precisely: when the process receives 759if C<$pid> is 0) has been received (a status change happens when the
760process terminates or is killed, or, when trace is true, additionally when
761it is stopped or continued). More precisely: when the process receives
547a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all 762a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
548changed/zombie children and call the callback. 763changed/zombie children and call the callback.
549 764
550It is valid (and fully supported) to install a child watcher after a child 765It is valid (and fully supported) to install a child watcher after a child
551has exited but before the event loop has started its next iteration (for 766has exited but before the event loop has started its next iteration (for
… …
558You can have as many pid watchers per pid as you want, they will all be 773You can have as many pid watchers per pid as you want, they will all be
559called. 774called.
560 775
561The C<child_ns> variant doesn't start (activate) the newly created watcher. 776The C<child_ns> variant doesn't start (activate) the newly created watcher.
562 777
563=item $w->set ($pid) 778=item $w->set ($pid, $trace)
564 779
565Reconfigures the watcher, see the constructor above for details. Can be called at 780Reconfigures the watcher, see the constructor above for details. Can be called at
566any time. 781any time.
567 782
568=item $current_pid = $w->pid 783=item $current_pid = $w->pid
569 784
570=item $old_pid = $w->pid ($new_pid)
571
572Returns the previously set process id and optionally set a new one. 785Returns the previously set process id and optionally set a new one.
573 786
574=item $exit_status = $w->rstatus 787=item $exit_status = $w->rstatus
575 788
576Return the exit/wait status (as returned by waitpid, see the waitpid entry 789Return the exit/wait status (as returned by waitpid, see the waitpid entry
… …
589=over 4 802=over 4
590 803
591=item $w = EV::stat $path, $interval, $callback 804=item $w = EV::stat $path, $interval, $callback
592 805
593=item $w = EV::stat_ns $path, $interval, $callback 806=item $w = EV::stat_ns $path, $interval, $callback
807
808=item $w = $loop->stat ($path, $interval, $callback)
809
810=item $w = $loop->stat_ns ($path, $interval, $callback)
594 811
595Call the callback when a file status change has been detected on 812Call the callback when a file status change has been detected on
596C<$path>. The C<$path> does not need to exist, changing from "path exists" 813C<$path>. The C<$path> does not need to exist, changing from "path exists"
597to "path does not exist" is a status change like any other. 814to "path does not exist" is a status change like any other.
598 815
… …
668=over 4 885=over 4
669 886
670=item $w = EV::idle $callback 887=item $w = EV::idle $callback
671 888
672=item $w = EV::idle_ns $callback 889=item $w = EV::idle_ns $callback
890
891=item $w = $loop->idle ($callback)
892
893=item $w = $loop->idle_ns ($callback)
673 894
674Call the callback when there are no other pending watchers of the same or 895Call the callback when there are no other pending watchers of the same or
675higher priority (excluding check, prepare and other idle watchers of the 896higher priority (excluding check, prepare and other idle watchers of the
676same or lower priority, of course). They are called idle watchers because 897same or lower priority, of course). They are called idle watchers because
677when the watcher is the highest priority pending event in the process, the 898when the watcher is the highest priority pending event in the process, the
… …
700 921
701=item $w = EV::prepare $callback 922=item $w = EV::prepare $callback
702 923
703=item $w = EV::prepare_ns $callback 924=item $w = EV::prepare_ns $callback
704 925
926=item $w = $loop->prepare ($callback)
927
928=item $w = $loop->prepare_ns ($callback)
929
705Call the callback just before the process would block. You can still 930Call the callback just before the process would block. You can still
706create/modify any watchers at this point. 931create/modify any watchers at this point.
707 932
708See the EV::check watcher, below, for explanations and an example. 933See the EV::check watcher, below, for explanations and an example.
709 934
… …
717=over 4 942=over 4
718 943
719=item $w = EV::check $callback 944=item $w = EV::check $callback
720 945
721=item $w = EV::check_ns $callback 946=item $w = EV::check_ns $callback
947
948=item $w = $loop->check ($callback)
949
950=item $w = $loop->check_ns ($callback)
722 951
723Call the callback just after the process wakes up again (after it has 952Call the callback just after the process wakes up again (after it has
724gathered events), but before any other callbacks have been invoked. 953gathered events), but before any other callbacks have been invoked.
725 954
726This is used to integrate other event-based software into the EV 955This is used to integrate other event-based software into the EV
… …
761 # make the dispatcher handle any new stuff 990 # make the dispatcher handle any new stuff
762 ... not shown 991 ... not shown
763 }; 992 };
764 993
765The callbacks of the created watchers will not be called as the watchers 994The callbacks of the created watchers will not be called as the watchers
766are destroyed before this cna happen (remember EV::check gets called 995are destroyed before this can happen (remember EV::check gets called
767first). 996first).
768 997
769The C<check_ns> variant doesn't start (activate) the newly created watcher. 998The C<check_ns> variant doesn't start (activate) the newly created watcher.
770 999
771=back 1000=back
… …
781 1010
782=item $w = EV::fork $callback 1011=item $w = EV::fork $callback
783 1012
784=item $w = EV::fork_ns $callback 1013=item $w = EV::fork_ns $callback
785 1014
1015=item $w = $loop->fork ($callback)
1016
1017=item $w = $loop->fork_ns ($callback)
1018
786Call the callback before the event loop is resumed in the child process 1019Call the callback before the event loop is resumed in the child process
787after a fork. 1020after a fork.
788 1021
789The C<fork_ns> variant doesn't start (activate) the newly created watcher. 1022The C<fork_ns> variant doesn't start (activate) the newly created watcher.
1023
1024=back
1025
1026
1027=head3 EMBED WATCHERS - when one backend isn't enough...
1028
1029This is a rather advanced watcher type that lets you embed one event loop
1030into another (currently only IO events are supported in the embedded
1031loop, other types of watchers might be handled in a delayed or incorrect
1032fashion and must not be used).
1033
1034See the libev documentation at
1035L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
1036(locally installed as F<EV::libev>) for more details.
1037
1038In short, this watcher is most useful on BSD systems without working
1039kqueue to still be able to handle a large number of sockets:
1040
1041 my $socket_loop;
1042
1043 # check wether we use SELECT or POLL _and_ KQUEUE is supported
1044 if (
1045 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
1046 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
1047 ) {
1048 # use kqueue for sockets
1049 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
1050 }
1051
1052 # use the default loop otherwise
1053 $socket_loop ||= EV::default_loop;
1054
1055=over 4
1056
1057=item $w = EV::embed $otherloop[, $callback]
1058
1059=item $w = EV::embed_ns $otherloop[, $callback]
1060
1061=item $w = $loop->embed ($otherloop[, $callback])
1062
1063=item $w = $loop->embed_ns ($otherloop[, $callback])
1064
1065Call the callback when the embedded event loop (C<$otherloop>) has any
1066I/O activity. The C<$callback> is optional: if it is missing, then the
1067embedded event loop will be managed automatically (which is recommended),
1068otherwise you have to invoke C<sweep> yourself.
1069
1070The C<embed_ns> variant doesn't start (activate) the newly created watcher.
1071
1072=back
1073
1074=head3 ASYNC WATCHERS - how to wake up another event loop
1075
1076Async watchers are provided by EV, but have little use in perl directly,
1077as perl neither supports threads running in parallel nor direct access to
1078signal handlers or other contexts where they could be of value.
1079
1080It is, however, possible to use them from the XS level.
1081
1082Please see the libev documentation for further details.
1083
1084=over 4
1085
1086=item $w = EV::async $callback
1087
1088=item $w = EV::async_ns $callback
1089
1090=item $w->send
1091
1092=item $bool = $w->async_pending
790 1093
791=back 1094=back
792 1095
793 1096
794=head1 PERL SIGNALS 1097=head1 PERL SIGNALS
… …
805to be called on every event loop iteration by installing a C<EV::check> 1108to be called on every event loop iteration by installing a C<EV::check>
806watcher: 1109watcher:
807 1110
808 my $async_check = EV::check sub { }; 1111 my $async_check = EV::check sub { };
809 1112
810This ensures that perl shortly gets into control for a short time, and 1113This ensures that perl gets into control for a short time to handle any
811also ensures slower overall operation. 1114pending signals, and also ensures (slightly) slower overall operation.
812 1115
813=head1 THREADS 1116=head1 ITHREADS
814 1117
815Threads are not supported by this module in any way. Perl pseudo-threads 1118Ithreads are not supported by this module in any way. Perl pseudo-threads
816is evil stuff and must die. As soon as Perl gains real threads I will work 1119is evil stuff and must die. Real threads as provided by Coro are fully
817on thread support for it. 1120supported (and enhanced support is available via L<Coro::EV>).
818 1121
819=head1 FORK 1122=head1 FORK
820 1123
821Most of the "improved" event delivering mechanisms of modern operating 1124Most of the "improved" event delivering mechanisms of modern operating
822systems have quite a few problems with fork(2) (to put it bluntly: it is 1125systems have quite a few problems with fork(2) (to put it bluntly: it is
… …
844 1147
8451; 11481;
846 1149
847=head1 SEE ALSO 1150=head1 SEE ALSO
848 1151
849L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as 1152L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
850event loop), L<Coro::EV> (efficient coroutines with EV). 1153event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
1154coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1155event-loop agnostic and portable event driven programming.
851 1156
852=head1 AUTHOR 1157=head1 AUTHOR
853 1158
854 Marc Lehmann <schmorp@schmorp.de> 1159 Marc Lehmann <schmorp@schmorp.de>
855 http://home.schmorp.de/ 1160 http://home.schmorp.de/
856 1161
857=cut 1162=cut
858 1163

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