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1NAME 1NAME
2 EV - perl interface to libev, a high performance full-featured event 2 EV - perl interface to libev, a high performance full-featured event
3 loop 3 loop
4 4
5SYNOPSIS 5SYNOPSIS
6 use EV; 6 use EV;
7 7
8 # TIMERS 8 # TIMERS
9 9
10 my $w = EV::timer 2, 0, sub { 10 my $w = EV::timer 2, 0, sub {
11 warn "is called after 2s"; 11 warn "is called after 2s";
12 }; 12 };
13 13
14 my $w = EV::timer 2, 2, sub { 14 my $w = EV::timer 2, 2, sub {
15 warn "is called roughly every 2s (repeat = 2)"; 15 warn "is called roughly every 2s (repeat = 2)";
16 }; 16 };
17 17
18 undef $w; # destroy event watcher again 18 undef $w; # destroy event watcher again
19 19
20 my $w = EV::periodic 0, 60, 0, sub { 20 my $w = EV::periodic 0, 60, 0, sub {
21 warn "is called every minute, on the minute, exactly"; 21 warn "is called every minute, on the minute, exactly";
22 }; 22 };
23 23
24 # IO 24 # IO
25 25
26 my $w = EV::io *STDIN, EV::READ, sub { 26 my $w = EV::io *STDIN, EV::READ, sub {
27 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask 27 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
28 warn "stdin is readable, you entered: ", <STDIN>; 28 warn "stdin is readable, you entered: ", <STDIN>;
29 }; 29 };
30 30
31 # SIGNALS 31 # SIGNALS
32 32
33 my $w = EV::signal 'QUIT', sub { 33 my $w = EV::signal 'QUIT', sub {
34 warn "sigquit received\n"; 34 warn "sigquit received\n";
35 }; 35 };
36 36
37 # CHILD/PID STATUS CHANGES 37 # CHILD/PID STATUS CHANGES
38 38
39 my $w = EV::child 666, 0, sub { 39 my $w = EV::child 666, 0, sub {
40 my ($w, $revents) = @_; 40 my ($w, $revents) = @_;
41 my $status = $w->rstatus; 41 my $status = $w->rstatus;
42 }; 42 };
43 43
44 # STAT CHANGES 44 # STAT CHANGES
45 my $w = EV::stat "/etc/passwd", 10, sub { 45 my $w = EV::stat "/etc/passwd", 10, sub {
46 my ($w, $revents) = @_; 46 my ($w, $revents) = @_;
47 warn $w->path, " has changed somehow.\n"; 47 warn $w->path, " has changed somehow.\n";
48 }; 48 };
49 49
50 # MAINLOOP 50 # MAINLOOP
51 EV::loop; # loop until EV::unloop is called or all watchers stop 51 EV::run; # loop until EV::break is called or all watchers stop
52 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled 52 EV::run EV::RUN_ONCE; # block until at least one event could be handled
53 EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block 53 EV::run EV::RUN_NOWAIT; # try to handle same events, but do not block
54
55BEFORE YOU START USING THIS MODULE
56 If you only need timer, I/O, signal, child and idle watchers and not the
57 advanced functionality of this module, consider using AnyEvent instead,
58 specifically the simplified API described in AE.
59
60 When used with EV as backend, the AE API is as fast as the native EV
61 API, but your programs/modules will still run with many other event
62 loops.
54 63
55DESCRIPTION 64DESCRIPTION
56 This module provides an interface to libev 65 This module provides an interface to libev
57 (<http://software.schmorp.de/pkg/libev.html>). While the documentation 66 (<http://software.schmorp.de/pkg/libev.html>). While the documentation
58 below is comprehensive, one might also consult the documentation of 67 below is comprehensive, one might also consult the documentation of
59 libev itself (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>) 68 libev itself (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
60 for more subtle details on watcher semantics or some discussion on the 69 perldoc EV::libev) for more subtle details on watcher semantics or some
61 available backends, or how to force a specific backend with 70 discussion on the available backends, or how to force a specific backend
62 "LIBEV_FLAGS", or just about in any case because it has much more 71 with "LIBEV_FLAGS", or just about in any case because it has much more
63 detailed information. 72 detailed information.
64 73
65 This module is very fast and scalable. It is actually so fast that you 74 This module is very fast and scalable. It is actually so fast that you
66 can use it through the AnyEvent module, stay portable to other event 75 can use it through the AnyEvent module, stay portable to other event
67 loops (if you don't rely on any watcher types not available through it) 76 loops (if you don't rely on any watcher types not available through it)
68 and still be faster than with any other event loop currently supported 77 and still be faster than with any other event loop currently supported
69 in Perl. 78 in Perl.
79
80 PORTING FROM EV 3.X to 4.X
81 EV version 4 introduces a number of incompatible changes summarised
82 here. According to the depreciation strategy used by libev, there is a
83 compatibility layer in place so programs should continue to run
84 unchanged (the XS interface lacks this layer, so programs using that one
85 need to be updated).
86
87 This compatibility layer will be switched off in some future release.
88
89 All changes relevant to Perl are renames of symbols, functions and
90 methods:
91
92 EV::loop => EV::run
93 EV::LOOP_NONBLOCK => EV::RUN_NOWAIT
94 EV::LOOP_ONESHOT => EV::RUN_ONCE
95
96 EV::unloop => EV::break
97 EV::UNLOOP_CANCEL => EV::BREAK_CANCEL
98 EV::UNLOOP_ONE => EV::BREAK_ONE
99 EV::UNLOOP_ALL => EV::BREAK_ALL
100
101 EV::TIMEOUT => EV::TIMER
102
103 EV::loop_count => EV::iteration
104 EV::loop_depth => EV::depth
105 EV::loop_verify => EV::verify
106
107 The loop object methods corresponding to the functions above have been
108 similarly renamed.
109
110 MODULE EXPORTS
111 This module does not export any symbols.
70 112
71EVENT LOOPS 113EVENT LOOPS
72 EV supports multiple event loops: There is a single "default event loop" 114 EV supports multiple event loops: There is a single "default event loop"
73 that can handle everything including signals and child watchers, and any 115 that can handle everything including signals and child watchers, and any
74 number of "dynamic event loops" that can use different backends (with 116 number of "dynamic event loops" that can use different backends (with
… …
81 default loop as this is fastest (perl-wise), best supported by other 123 default loop as this is fastest (perl-wise), best supported by other
82 modules (e.g. AnyEvent or Coro) and most portable event loop. 124 modules (e.g. AnyEvent or Coro) and most portable event loop.
83 125
84 For specific programs you can create additional event loops dynamically. 126 For specific programs you can create additional event loops dynamically.
85 127
128 If you want to take advantage of kqueue (which often works properly for
129 sockets only) even though the default loop doesn't enable it, you can
130 *embed* a kqueue loop into the default loop: running the default loop
131 will then also service the kqueue loop to some extent. See the example
132 in the section about embed watchers for an example on how to achieve
133 that.
134
86 $loop = new EV::loop [$flags] 135 $loop = new EV::Loop [$flags]
87 Create a new event loop as per the specified flags. Please refer to 136 Create a new event loop as per the specified flags. Please refer to
88 the "ev_loop_new ()" function description in the libev documentation 137 the "ev_loop_new ()" function description in the libev documentation
89 (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI 138 (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI
90 ONS>) for more info. 139 ONS>, or locally-installed as EV::libev manpage) for more info.
91 140
92 The loop will automatically be destroyed when it is no longer 141 The loop will automatically be destroyed when it is no longer
93 referenced by any watcher and the loop object goes out of scope. 142 referenced by any watcher and the loop object goes out of scope.
94 143
95 Using "EV::FLAG_FORKCHECK" is recommended, as only the default event 144 If you are not embedding the loop, then Using "EV::FLAG_FORKCHECK"
96 loop is protected by this module. 145 is recommended, as only the default event loop is protected by this
146 module. If you *are* embedding this loop in the default loop, this
147 is not necessary, as "EV::embed" automatically does the right thing
148 on fork.
97 149
98 $loop->loop_fork 150 $loop->loop_fork
99 Must be called after a fork in the child, before entering or 151 Must be called after a fork in the child, before entering or
100 continuing the event loop. An alternative is to use 152 continuing the event loop. An alternative is to use
101 "EV::FLAG_FORKCHECK" which calls this function automatically, at 153 "EV::FLAG_FORKCHECK" which calls this function automatically, at
102 some performance loss (refer to the libev documentation). 154 some performance loss (refer to the libev documentation).
103 155
104 $loop->loop_verify 156 $loop->verify
105 Calls "ev_verify" to make internal consistency checks (for debugging 157 Calls "ev_verify" to make internal consistency checks (for debugging
106 libev) and abort the program if any data structures wree found to be 158 libev) and abort the program if any data structures were found to be
107 corrupted. 159 corrupted.
108 160
109 $loop = EV::default_loop [$flags] 161 $loop = EV::default_loop [$flags]
110 Return the default loop (which is a singleton object). Since this 162 Return the default loop (which is a singleton object). Since this
111 module already creates the default loop with default flags, 163 module already creates the default loop with default flags,
112 specifying flags here will not have any effect unless you destroy 164 specifying flags here will not have any effect unless you destroy
113 the default loop. 165 the default loop first, which isn't supported. So in short: don't do
166 it, and if you break it, you get to keep the pieces.
114 167
115BASIC INTERFACE 168BASIC INTERFACE
116 $EV::DIED 169 $EV::DIED
117 Must contain a reference to a function that is called when a 170 Must contain a reference to a function that is called when a
118 callback throws an exception (with $@ containing the error). The 171 callback throws an exception (with $@ containing the error). The
… …
135 Returns the current time in (fractional) seconds since the epoch. 188 Returns the current time in (fractional) seconds since the epoch.
136 189
137 $time = EV::now 190 $time = EV::now
138 $time = $loop->now 191 $time = $loop->now
139 Returns the time the last event loop iteration has been started. 192 Returns the time the last event loop iteration has been started.
140 This is the time that (relative) timers are based on, and refering 193 This is the time that (relative) timers are based on, and referring
141 to it is usually faster then calling EV::time. 194 to it is usually faster then calling EV::time.
195
196 EV::now_update
197 $loop->now_update
198 Establishes the current time by querying the kernel, updating the
199 time returned by "EV::now" in the progress. This is a costly
200 operation and is usually done automatically within "EV::loop".
201
202 This function is rarely useful, but when some event callback runs
203 for a very long time without entering the event loop, updating
204 libev's idea of the current time is a good idea.
205
206 EV::suspend
207 $loop->suspend
208 EV::resume
209 $loop->resume
210 These two functions suspend and resume a loop, for use when the loop
211 is not used for a while and timeouts should not be processed.
212
213 A typical use case would be an interactive program such as a game:
214 When the user presses "^Z" to suspend the game and resumes it an
215 hour later it would be best to handle timeouts as if no time had
216 actually passed while the program was suspended. This can be
217 achieved by calling "suspend" in your "SIGTSTP" handler, sending
218 yourself a "SIGSTOP" and calling "resume" directly afterwards to
219 resume timer processing.
220
221 Effectively, all "timer" watchers will be delayed by the time spend
222 between "suspend" and "resume", and all "periodic" watchers will be
223 rescheduled (that is, they will lose any events that would have
224 occured while suspended).
225
226 After calling "suspend" you must not call *any* function on the
227 given loop other than "resume", and you must not call "resume"
228 without a previous call to "suspend".
229
230 Calling "suspend"/"resume" has the side effect of updating the event
231 loop time (see "now_update").
142 232
143 $backend = EV::backend 233 $backend = EV::backend
144 $backend = $loop->backend 234 $backend = $loop->backend
145 Returns an integer describing the backend used by libev 235 Returns an integer describing the backend used by libev
146 (EV::METHOD_SELECT or EV::METHOD_EPOLL). 236 (EV::BACKEND_SELECT or EV::BACKEND_EPOLL).
147 237
148 EV::loop [$flags] 238 $active = EV::run [$flags]
149 $loop->loop ([$flags]) 239 $active = $loop->run ([$flags])
150 Begin checking for events and calling callbacks. It returns when a 240 Begin checking for events and calling callbacks. It returns when a
151 callback calls EV::unloop. 241 callback calls EV::break or the flasg are nonzero (in which case the
242 return value is true) or when there are no active watchers which
243 reference the loop (keepalive is true), in which case the return
244 value will be false. The returnv alue can generally be interpreted
245 as "if true, there is more work left to do".
152 246
153 The $flags argument can be one of the following: 247 The $flags argument can be one of the following:
154 248
155 0 as above 249 0 as above
156 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 250 EV::RUN_ONCE block at most once (wait, but do not loop)
157 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 251 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
158 252
159 EV::unloop [$how] 253 EV::break [$how]
160 $loop->unloop ([$how]) 254 $loop->break ([$how])
161 When called with no arguments or an argument of EV::UNLOOP_ONE, 255 When called with no arguments or an argument of EV::BREAK_ONE, makes
162 makes the innermost call to EV::loop return. 256 the innermost call to EV::loop return.
163 257
164 When called with an argument of EV::UNLOOP_ALL, all calls to 258 When called with an argument of EV::BREAK_ALL, all calls to EV::loop
165 EV::loop will return as fast as possible. 259 will return as fast as possible.
166 260
167 $count = EV::loop_count 261 When called with an argument of EV::BREAK_CANCEL, any pending break
168 $count = $loop->loop_count 262 will be cancelled.
263
264 $count = EV::iteration
265 $count = $loop->iteration
169 Return the number of times the event loop has polled for new events. 266 Return the number of times the event loop has polled for new events.
170 Sometiems useful as a generation counter. 267 Sometimes useful as a generation counter.
171 268
172 EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 269 EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
173 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 270 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
174 This function rolls together an I/O and a timer watcher for a single 271 This function rolls together an I/O and a timer watcher for a single
175 one-shot event without the need for managing a watcher object. 272 one-shot event without the need for managing a watcher object.
… …
184 Otherwise a EV::timer with this value will be started. 281 Otherwise a EV::timer with this value will be started.
185 282
186 When an error occurs or either the timeout or I/O watcher triggers, 283 When an error occurs or either the timeout or I/O watcher triggers,
187 then the callback will be called with the received event set (in 284 then the callback will be called with the received event set (in
188 general you can expect it to be a combination of "EV::ERROR", 285 general you can expect it to be a combination of "EV::ERROR",
189 "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). 286 "EV::READ", "EV::WRITE" and "EV::TIMER").
190 287
191 EV::once doesn't return anything: the watchers stay active till 288 EV::once doesn't return anything: the watchers stay active till
192 either of them triggers, then they will be stopped and freed, and 289 either of them triggers, then they will be stopped and freed, and
193 the callback invoked. 290 the callback invoked.
194 291
195 EV::feed_fd_event ($fd, $revents) 292 EV::feed_fd_event $fd, $revents
196 $loop->feed_fd_event ($fd, $revents) 293 $loop->feed_fd_event ($fd, $revents)
197 Feed an event on a file descriptor into EV. EV will react to this 294 Feed an event on a file descriptor into EV. EV will react to this
198 call as if the readyness notifications specified by $revents (a 295 call as if the readyness notifications specified by $revents (a
199 combination of "EV::READ" and "EV::WRITE") happened on the file 296 combination of "EV::READ" and "EV::WRITE") happened on the file
200 descriptor $fd. 297 descriptor $fd.
201 298
202 EV::feed_signal_event ($signal) 299 EV::feed_signal_event $signal
203 Feed a signal event into EV. EV will react to this call as if the 300 Feed a signal event into the default loop. EV will react to this
204 signal specified by $signal had occured. 301 call as if the signal specified by $signal had occured.
302
303 EV::feed_signal $signal
304 Feed a signal event into EV - unlike "EV::feed_signal_event", this
305 works regardless of which loop has registered the signal, and is
306 mainly useful fro custom signal implementations.
205 307
206 EV::set_io_collect_interval $time 308 EV::set_io_collect_interval $time
207 $loop->set_io_collect_interval ($time) 309 $loop->set_io_collect_interval ($time)
208 EV::set_timeout_collect_interval $time 310 EV::set_timeout_collect_interval $time
209 $loop->set_timeout_collect_interval ($time) 311 $loop->set_timeout_collect_interval ($time)
210 These advanced functions set the minimum block interval when polling 312 These advanced functions set the minimum block interval when polling
211 for I/O events and the minimum wait interval for timer events. See 313 for I/O events and the minimum wait interval for timer events. See
212 the libev documentation at 314 the libev documentation at
213 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT 315 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT
214 ROLLING_THE_EVENT_LOOP> for a more detailed discussion. 316 ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more
317 detailed discussion.
318
319 $count = EV::pending_count
320 $count = $loop->pending_count
321 Returns the number of currently pending watchers.
322
323 EV::invoke_pending
324 $loop->invoke_pending
325 Invoke all currently pending watchers.
215 326
216WATCHER OBJECTS 327WATCHER OBJECTS
217 A watcher is an object that gets created to record your interest in some 328 A watcher is an object that gets created to record your interest in some
218 event. For instance, if you want to wait for STDIN to become readable, 329 event. For instance, if you want to wait for STDIN to become readable,
219 you would create an EV::io watcher for that: 330 you would create an EV::io watcher for that:
220 331
221 my $watcher = EV::io *STDIN, EV::READ, sub { 332 my $watcher = EV::io *STDIN, EV::READ, sub {
222 my ($watcher, $revents) = @_; 333 my ($watcher, $revents) = @_;
223 warn "yeah, STDIN should now be readable without blocking!\n" 334 warn "yeah, STDIN should now be readable without blocking!\n"
224 }; 335 };
225 336
226 All watchers can be active (waiting for events) or inactive (paused). 337 All watchers can be active (waiting for events) or inactive (paused).
227 Only active watchers will have their callbacks invoked. All callbacks 338 Only active watchers will have their callbacks invoked. All callbacks
228 will be called with at least two arguments: the watcher and a bitmask of 339 will be called with at least two arguments: the watcher and a bitmask of
229 received events. 340 received events.
230 341
231 Each watcher type has its associated bit in revents, so you can use the 342 Each watcher type has its associated bit in revents, so you can use the
232 same callback for multiple watchers. The event mask is named after the 343 same callback for multiple watchers. The event mask is named after the
233 type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 344 type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
234 EV::periodic sets EV::PERIODIC and so on, with the exception of I/O 345 EV::periodic sets EV::PERIODIC and so on, with the exception of I/O
235 events (which can set both EV::READ and EV::WRITE bits), and EV::timer 346 events (which can set both EV::READ and EV::WRITE bits).
236 (which uses EV::TIMEOUT).
237 347
238 In the rare case where one wants to create a watcher but not start it at 348 In the rare case where one wants to create a watcher but not start it at
239 the same time, each constructor has a variant with a trailing "_ns" in 349 the same time, each constructor has a variant with a trailing "_ns" in
240 its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. 350 its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
241 351
… …
306 the watcher isn't pending it does nothing and returns 0. 416 the watcher isn't pending it does nothing and returns 0.
307 417
308 $previous_state = $w->keepalive ($bool) 418 $previous_state = $w->keepalive ($bool)
309 Normally, "EV::loop" will return when there are no active watchers 419 Normally, "EV::loop" will return when there are no active watchers
310 (which is a "deadlock" because no progress can be made anymore). 420 (which is a "deadlock" because no progress can be made anymore).
311 This is convinient because it allows you to start your watchers (and 421 This is convenient because it allows you to start your watchers (and
312 your jobs), call "EV::loop" once and when it returns you know that 422 your jobs), call "EV::loop" once and when it returns you know that
313 all your jobs are finished (or they forgot to register some watchers 423 all your jobs are finished (or they forgot to register some watchers
314 for their task :). 424 for their task :).
315 425
316 Sometimes, however, this gets in your way, for example when the 426 Sometimes, however, this gets in your way, for example when the
… …
323 433
324 In this case you can clear the keepalive status, which means that 434 In this case you can clear the keepalive status, which means that
325 even though your watcher is active, it won't keep "EV::loop" from 435 even though your watcher is active, it won't keep "EV::loop" from
326 returning. 436 returning.
327 437
328 The initial value for keepalive is true (enabled), and you cna 438 The initial value for keepalive is true (enabled), and you can
329 change it any time. 439 change it any time.
330 440
331 Example: Register an I/O watcher for some UDP socket but do not keep 441 Example: Register an I/O watcher for some UDP socket but do not keep
332 the event loop from running just because of that watcher. 442 the event loop from running just because of that watcher.
333 443
334 my $udp_socket = ... 444 my $udp_socket = ...
335 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 445 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
336 $1000udp_watcher->keepalive (0); 446 $udp_watcher->keepalive (0);
337 447
338 $loop = $w->loop 448 $loop = $w->loop
339 Return the loop that this watcher is attached to. 449 Return the loop that this watcher is attached to.
340 450
341WATCHER TYPES 451WATCHER TYPES
… …
448 to system time: 558 to system time:
449 559
450 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; 560 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
451 561
452 That doesn't mean there will always be 3600 seconds in between 562 That doesn't mean there will always be 3600 seconds in between
453 triggers, but only that the the clalback will be called when the 563 triggers, but only that the the callback will be called when the
454 system time shows a full hour (UTC). 564 system time shows a full hour (UTC).
455 565
456 Another way to think about it (for the mathematically inclined) 566 Another way to think about it (for the mathematically inclined)
457 is that EV::periodic will try to run the callback in this mode 567 is that EV::periodic will try to run the callback in this mode
458 at the next possible time where "$time = $at (mod $interval)", 568 at the next possible time where "$time = $at (mod $interval)",
… …
507 Return the time that the watcher is expected to trigger next. 617 Return the time that the watcher is expected to trigger next.
508 618
509 SIGNAL WATCHERS - signal me when a signal gets signalled! 619 SIGNAL WATCHERS - signal me when a signal gets signalled!
510 $w = EV::signal $signal, $callback 620 $w = EV::signal $signal, $callback
511 $w = EV::signal_ns $signal, $callback 621 $w = EV::signal_ns $signal, $callback
622 $w = $loop->signal ($signal, $callback)
623 $w = $loop->signal_ns ($signal, $callback)
512 Call the callback when $signal is received (the signal can be 624 Call the callback when $signal is received (the signal can be
513 specified by number or by name, just as with "kill" or %SIG). 625 specified by number or by name, just as with "kill" or %SIG).
626
627 Only one event loop can grab a given signal - attempting to grab the
628 same signal from two EV loops will crash the program immediately or
629 cause data corruption.
514 630
515 EV will grab the signal for the process (the kernel only allows one 631 EV will grab the signal for the process (the kernel only allows one
516 component to receive a signal at a time) when you start a signal 632 component to receive a signal at a time) when you start a signal
517 watcher, and removes it again when you stop it. Perl does the same 633 watcher, and removes it again when you stop it. Perl does the same
518 when you add/remove callbacks to %SIG, so watch out. 634 when you add/remove callbacks to %SIG, so watch out.
… …
692 $w = $loop->check_ns ($callback) 808 $w = $loop->check_ns ($callback)
693 Call the callback just after the process wakes up again (after it 809 Call the callback just after the process wakes up again (after it
694 has gathered events), but before any other callbacks have been 810 has gathered events), but before any other callbacks have been
695 invoked. 811 invoked.
696 812
697 This is used to integrate other event-based software into the EV 813 This can be used to integrate other event-based software into the EV
698 mainloop: You register a prepare callback and in there, you create 814 mainloop: You register a prepare callback and in there, you create
699 io and timer watchers as required by the other software. Here is a 815 io and timer watchers as required by the other software. Here is a
700 real-world example of integrating Net::SNMP (with some details left 816 real-world example of integrating Net::SNMP (with some details left
701 out): 817 out):
702 818
… …
733 # make the dispatcher handle any new stuff 849 # make the dispatcher handle any new stuff
734 ... not shown 850 ... not shown
735 }; 851 };
736 852
737 The callbacks of the created watchers will not be called as the 853 The callbacks of the created watchers will not be called as the
738 watchers are destroyed before this cna happen (remember EV::check 854 watchers are destroyed before this can happen (remember EV::check
739 gets called first). 855 gets called first).
740 856
741 The "check_ns" variant doesn't start (activate) the newly created 857 The "check_ns" variant doesn't start (activate) the newly created
742 watcher. 858 watcher.
859
860 EV::CHECK constant issues
861 Like all other watcher types, there is a bitmask constant for use in
862 $revents and other places. The "EV::CHECK" is special as it has the
863 same name as the "CHECK" sub called by Perl. This doesn't cause big
864 issues on newer perls (beginning with 5.8.9), but it means thatthe
865 constant must be *inlined*, i.e. runtime calls will not work. That
866 means that as long as you always "use EV" and then "EV::CHECK" you
867 are on the safe side.
743 868
744 FORK WATCHERS - the audacity to resume the event loop after a fork 869 FORK WATCHERS - the audacity to resume the event loop after a fork
745 Fork watchers are called when a "fork ()" was detected. The invocation 870 Fork watchers are called when a "fork ()" was detected. The invocation
746 is done before the event loop blocks next and before "check" watchers 871 is done before the event loop blocks next and before "check" watchers
747 are being called, and only in the child after the fork. 872 are being called, and only in the child after the fork.
… …
762 embedded loop, other types of watchers might be handled in a delayed or 887 embedded loop, other types of watchers might be handled in a delayed or
763 incorrect fashion and must not be used). 888 incorrect fashion and must not be used).
764 889
765 See the libev documentation at 890 See the libev documentation at
766 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code 891 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code
767 _when_one_backend_> for more details. 892 _when_one_backend_> (locally installed as EV::libev) for more details.
768 893
769 In short, this watcher is most useful on BSD systems without working 894 In short, this watcher is most useful on BSD systems without working
770 kqueue to still be able to handle a large number of sockets: 895 kqueue to still be able to handle a large number of sockets:
771 896
772 my $socket_loop; 897 my $socket_loop;
773 898
774 # check wether we use SELECT or POLL _and_ KQUEUE is supported 899 # check wether we use SELECT or POLL _and_ KQUEUE is supported
775 if ( 900 if (
776 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 901 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
777 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 902 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
778 ) { 903 ) {
779 # use kqueue for sockets 904 # use kqueue for sockets
780 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 905 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
781 } 906 }
782 907
783 # use the default loop otherwise 908 # use the default loop otherwise
784 $socket_loop ||= EV::default_loop; 909 $socket_loop ||= EV::default_loop;
785 910
786 $w = EV::embed $otherloop, $callback 911 $w = EV::embed $otherloop[, $callback]
787 $w = EV::embed_ns $otherloop, $callback 912 $w = EV::embed_ns $otherloop[, $callback]
788 $w = $loop->embed ($otherloop, $callback) 913 $w = $loop->embed ($otherloop[, $callback])
789 $w = $loop->embed_ns ($otherloop, $callback) 914 $w = $loop->embed_ns ($otherloop[, $callback])
790 Call the callback when the embedded event loop ($otherloop) has any 915 Call the callback when the embedded event loop ($otherloop) has any
791 I/O activity. The $callback should alwas be specified as "undef" in 916 I/O activity. The $callback is optional: if it is missing, then the
792 this version of EV, which means the embedded event loop will be 917 embedded event loop will be managed automatically (which is
793 managed automatically. 918 recommended), otherwise you have to invoke "sweep" yourself.
794 919
795 The "embed_ns" variant doesn't start (activate) the newly created 920 The "embed_ns" variant doesn't start (activate) the newly created
796 watcher. 921 watcher.
797 922
798 ASYNC WATCHERS - how to wake up another event loop 923 ASYNC WATCHERS - how to wake up another event loop
799 Async watchers are provided by EV, but have little use in perl directly, 924 Async watchers are provided by EV, but have little use in perl directly,
800 as perl neither supports threads nor direct access to signal handlers or 925 as perl neither supports threads running in parallel nor direct access
801 other contexts where they could be of value. 926 to signal handlers or other contexts where they could be of value.
802 927
803 It is, however, possible to use them from the XS level. 928 It is, however, possible to use them from the XS level.
804 929
805 Please see the libev documentation for further details. 930 Please see the libev documentation for further details.
806 931
807 $w = EV::async $callback 932 $w = EV::async $callback
808 $w = EV::async_ns $callback 933 $w = EV::async_ns $callback
934 $w = $loop->async ($callback)
935 $w = $loop->async_ns ($callback)
809 $w->send 936 $w->send
810 $bool = $w->async_pending 937 $bool = $w->async_pending
938
939 CLEANUP WATCHERS - how to clean up when the event loop goes away
940 Cleanup watchers are not supported on the Perl level, they can only be
941 used via XS currently.
811 942
812PERL SIGNALS 943PERL SIGNALS
813 While Perl signal handling (%SIG) is not affected by EV, the behaviour 944 While Perl signal handling (%SIG) is not affected by EV, the behaviour
814 with EV is as the same as any other C library: Perl-signals will only be 945 with EV is as the same as any other C library: Perl-signals will only be
815 handled when Perl runs, which means your signal handler might be invoked 946 handled when Perl runs, which means your signal handler might be invoked
… …
825 my $async_check = EV::check sub { }; 956 my $async_check = EV::check sub { };
826 957
827 This ensures that perl gets into control for a short time to handle any 958 This ensures that perl gets into control for a short time to handle any
828 pending signals, and also ensures (slightly) slower overall operation. 959 pending signals, and also ensures (slightly) slower overall operation.
829 960
830THREADS 961ITHREADS
831 Threads are not supported by this module in any way. Perl pseudo-threads 962 Ithreads are not supported by this module in any way. Perl
832 is evil stuff and must die. As soon as Perl gains real threads I will 963 pseudo-threads is evil stuff and must die. Real threads as provided by
833 work on thread support for it. 964 Coro are fully supported (and enhanced support is available via
965 Coro::EV).
834 966
835FORK 967FORK
836 Most of the "improved" event delivering mechanisms of modern operating 968 Most of the "improved" event delivering mechanisms of modern operating
837 systems have quite a few problems with fork(2) (to put it bluntly: it is 969 systems have quite a few problems with fork(2) (to put it bluntly: it is
838 not supported and usually destructive). Libev makes it possible to work 970 not supported and usually destructive). Libev makes it possible to work
… …
848 980
849 On win32, there is no notion of fork so all this doesn't apply, of 981 On win32, there is no notion of fork so all this doesn't apply, of
850 course. 982 course.
851 983
852SEE ALSO 984SEE ALSO
853 EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event 985 EV::MakeMaker - MakeMaker interface to XS API, EV::ADNS (asynchronous
854 loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines 986 DNS), Glib::EV (makes Glib/Gtk2 use EV as event loop), EV::Glib (embed
855 with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop 987 Glib into EV), Coro::EV (efficient thread integration), Net::SNMP::EV
856 agnostic and portable event driven programming. 988 (asynchronous SNMP), AnyEvent for event-loop agnostic and portable event
989 driven programming.
857 990
858AUTHOR 991AUTHOR
859 Marc Lehmann <schmorp@schmorp.de> 992 Marc Lehmann <schmorp@schmorp.de>
860 http://home.schmorp.de/ 993 http://home.schmorp.de/
861 994

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