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

Comparing EV/README (file contents):
Revision 1.19 by root, Tue Dec 18 01:37:46 2007 UTC vs.
Revision 1.31 by root, Wed Nov 19 10:33:32 2008 UTC

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, 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::loop; # loop until EV::unloop is called or all watchers stop
52 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled 52 EV::loop EV::LOOP_ONESHOT; # 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::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
54 54
55DESCRIPTION 55DESCRIPTION
56 This module provides an interface to libev 56 This module provides an interface to libev
57 (<http://software.schmorp.de/pkg/libev.html>). While the documentation 57 (<http://software.schmorp.de/pkg/libev.html>). While the documentation
58 below is comprehensive, one might also consult the documentation of 58 below is comprehensive, one might also consult the documentation of
59 libev itself (<http://cvs.schmorp.de/libev/ev.html>) for more subtle 59 libev itself (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
60 details on watcher semantics or some discussion on the available 60 perldoc EV::libev) for more subtle details on watcher semantics or some
61 backends, or how to force a specific backend with "LIBEV_FLAGS", or just 61 discussion on the available backends, or how to force a specific backend
62 about in any case because it has much more detailed information. 62 with "LIBEV_FLAGS", or just about in any case because it has much more
63 detailed information.
64
65 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
67 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
69 in Perl.
70
71 MODULE EXPORTS
72 This module does not export any symbols.
73
74EVENT LOOPS
75 EV supports multiple event loops: There is a single "default event loop"
76 that can handle everything including signals and child watchers, and any
77 number of "dynamic event loops" that can use different backends (with
78 various limitations), but no child and signal watchers.
79
80 You do not have to do anything to create the default event loop: When
81 the module is loaded a suitable backend is selected on the premise of
82 selecting a working backend (which for example rules out kqueue on most
83 BSDs). Modules should, unless they have "special needs" always use the
84 default loop as this is fastest (perl-wise), best supported by other
85 modules (e.g. AnyEvent or Coro) and most portable event loop.
86
87 For specific programs you can create additional event loops dynamically.
88
89 If you want to take advantage of kqueue (which often works properly for
90 sockets only) even though the default loop doesn't enable it, you can
91 *embed* a kqueue loop into the default loop: running the default loop
92 will then also service the kqueue loop to some extent. See the example
93 in the section about embed watchers for an example on how to achieve
94 that.
95
96 $loop = new EV::loop [$flags]
97 Create a new event loop as per the specified flags. Please refer to
98 the "ev_loop_new ()" function description in the libev documentation
99 (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI
100 ONS>, or locally-installed as EV::libev manpage) for more info.
101
102 The loop will automatically be destroyed when it is no longer
103 referenced by any watcher and the loop object goes out of scope.
104
105 If you are not embedding the loop, then Using "EV::FLAG_FORKCHECK"
106 is recommended, as only the default event loop is protected by this
107 module. If you *are* embedding this loop in the default loop, this
108 is not necessary, as "EV::embed" automatically does the right thing
109 on fork.
110
111 $loop->loop_fork
112 Must be called after a fork in the child, before entering or
113 continuing the event loop. An alternative is to use
114 "EV::FLAG_FORKCHECK" which calls this function automatically, at
115 some performance loss (refer to the libev documentation).
116
117 $loop->loop_verify
118 Calls "ev_verify" to make internal consistency checks (for debugging
119 libev) and abort the program if any data structures were found to be
120 corrupted.
121
122 $loop = EV::default_loop [$flags]
123 Return the default loop (which is a singleton object). Since this
124 module already creates the default loop with default flags,
125 specifying flags here will not have any effect unless you destroy
126 the default loop first, which isn't supported. So in short: don't do
127 it, and if you break it, you get to keep the pieces.
63 128
64BASIC INTERFACE 129BASIC INTERFACE
65 $EV::DIED 130 $EV::DIED
66 Must contain a reference to a function that is called when a 131 Must contain a reference to a function that is called when a
67 callback throws an exception (with $@ containing the error). The 132 callback throws an exception (with $@ containing the error). The
68 default prints an informative message and continues. 133 default prints an informative message and continues.
69 134
70 If this callback throws an exception it will be silently ignored. 135 If this callback throws an exception it will be silently ignored.
71 136
137 $flags = EV::supported_backends
138 $flags = EV::recommended_backends
139 $flags = EV::embeddable_backends
140 Returns the set (see "EV::BACKEND_*" flags) of backends supported by
141 this instance of EV, the set of recommended backends (supposed to be
142 good) for this platform and the set of embeddable backends (see
143 EMBED WATCHERS).
144
145 EV::sleep $seconds
146 Block the process for the given number of (fractional) seconds.
147
72 $time = EV::time 148 $time = EV::time
73 Returns the current time in (fractional) seconds since the epoch. 149 Returns the current time in (fractional) seconds since the epoch.
74 150
75 $time = EV::now 151 $time = EV::now
152 $time = $loop->now
76 Returns the time the last event loop iteration has been started. 153 Returns the time the last event loop iteration has been started.
77 This is the time that (relative) timers are based on, and refering 154 This is the time that (relative) timers are based on, and referring
78 to it is usually faster then calling EV::time. 155 to it is usually faster then calling EV::time.
79 156
80 $method = EV::method 157 $backend = EV::backend
158 $backend = $loop->backend
81 Returns an integer describing the backend used by libev 159 Returns an integer describing the backend used by libev
82 (EV::METHOD_SELECT or EV::METHOD_EPOLL). 160 (EV::BACKEND_SELECT or EV::BACKEND_EPOLL).
83 161
84 EV::loop [$flags] 162 EV::loop [$flags]
163 $loop->loop ([$flags])
85 Begin checking for events and calling callbacks. It returns when a 164 Begin checking for events and calling callbacks. It returns when a
86 callback calls EV::unloop. 165 callback calls EV::unloop.
87 166
88 The $flags argument can be one of the following: 167 The $flags argument can be one of the following:
89 168
90 0 as above 169 0 as above
91 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 170 EV::LOOP_ONESHOT block at most once (wait, but do not loop)
92 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 171 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
93 172
94 EV::unloop [$how] 173 EV::unloop [$how]
174 $loop->unloop ([$how])
95 When called with no arguments or an argument of EV::UNLOOP_ONE, 175 When called with no arguments or an argument of EV::UNLOOP_ONE,
96 makes the innermost call to EV::loop return. 176 makes the innermost call to EV::loop return.
97 177
98 When called with an argument of EV::UNLOOP_ALL, all calls to 178 When called with an argument of EV::UNLOOP_ALL, all calls to
99 EV::loop will return as fast as possible. 179 EV::loop will return as fast as possible.
100 180
101 $count = EV::loop_count 181 $count = EV::loop_count
182 $count = $loop->loop_count
102 Return the number of times the event loop has polled for new events. 183 Return the number of times the event loop has polled for new events.
103 Sometiems useful as a generation counter. 184 Sometimes useful as a generation counter.
104 185
105 EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 186 EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
187 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
106 This function rolls together an I/O and a timer watcher for a single 188 This function rolls together an I/O and a timer watcher for a single
107 one-shot event without the need for managing a watcher object. 189 one-shot event without the need for managing a watcher object.
108 190
109 If $fh_or_undef is a filehandle or file descriptor, then $events 191 If $fh_or_undef is a filehandle or file descriptor, then $events
110 must be a bitset containing either "EV::READ", "EV::WRITE" or 192 must be a bitset containing either "EV::READ", "EV::WRITE" or
… …
115 If timeout is "undef" or negative, then there will be no timeout. 197 If timeout is "undef" or negative, then there will be no timeout.
116 Otherwise a EV::timer with this value will be started. 198 Otherwise a EV::timer with this value will be started.
117 199
118 When an error occurs or either the timeout or I/O watcher triggers, 200 When an error occurs or either the timeout or I/O watcher triggers,
119 then the callback will be called with the received event set (in 201 then the callback will be called with the received event set (in
120 general you can expect it to be a combination of "EV:ERROR", 202 general you can expect it to be a combination of "EV::ERROR",
121 "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). 203 "EV::READ", "EV::WRITE" and "EV::TIMEOUT").
122 204
123 EV::once doesn't return anything: the watchers stay active till 205 EV::once doesn't return anything: the watchers stay active till
124 either of them triggers, then they will be stopped and freed, and 206 either of them triggers, then they will be stopped and freed, and
125 the callback invoked. 207 the callback invoked.
126 208
127 EV::feed_fd_event ($fd, $revents) 209 EV::feed_fd_event ($fd, $revents)
210 $loop->feed_fd_event ($fd, $revents)
128 Feed an event on a file descriptor into EV. EV will react to this 211 Feed an event on a file descriptor into EV. EV will react to this
129 call as if the readyness notifications specified by $revents (a 212 call as if the readyness notifications specified by $revents (a
130 combination of "EV::READ" and "EV::WRITE") happened on the file 213 combination of "EV::READ" and "EV::WRITE") happened on the file
131 descriptor $fd. 214 descriptor $fd.
132 215
133 EV::feed_signal_event ($signal) 216 EV::feed_signal_event ($signal)
134 Feed a signal event into EV. EV will react to this call as if the 217 Feed a signal event into EV. EV will react to this call as if the
135 signal specified by $signal had occured. 218 signal specified by $signal had occured.
136 219
220 EV::set_io_collect_interval $time
221 $loop->set_io_collect_interval ($time)
222 EV::set_timeout_collect_interval $time
223 $loop->set_timeout_collect_interval ($time)
224 These advanced functions set the minimum block interval when polling
225 for I/O events and the minimum wait interval for timer events. See
226 the libev documentation at
227 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT
228 ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more
229 detailed discussion.
230
137 WATCHER OBJECTS 231WATCHER OBJECTS
138 A watcher is an object that gets created to record your interest in some 232 A watcher is an object that gets created to record your interest in some
139 event. For instance, if you want to wait for STDIN to become readable, 233 event. For instance, if you want to wait for STDIN to become readable,
140 you would create an EV::io watcher for that: 234 you would create an EV::io watcher for that:
141 235
142 my $watcher = EV::io *STDIN, EV::READ, sub { 236 my $watcher = EV::io *STDIN, EV::READ, sub {
143 my ($watcher, $revents) = @_; 237 my ($watcher, $revents) = @_;
144 warn "yeah, STDIN should not be readable without blocking!\n" 238 warn "yeah, STDIN should now be readable without blocking!\n"
145 }; 239 };
146 240
147 All watchers can be active (waiting for events) or inactive (paused). 241 All watchers can be active (waiting for events) or inactive (paused).
148 Only active watchers will have their callbacks invoked. All callbacks 242 Only active watchers will have their callbacks invoked. All callbacks
149 will be called with at least two arguments: the watcher and a bitmask of 243 will be called with at least two arguments: the watcher and a bitmask of
150 received events. 244 received events.
151 245
152 Each watcher type has its associated bit in revents, so you can use the 246 Each watcher type has its associated bit in revents, so you can use the
153 same callback for multiple watchers. The event mask is named after the 247 same callback for multiple watchers. The event mask is named after the
154 type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 248 type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
155 EV::periodic sets EV::PERIODIC and so on, with the exception of I/O 249 EV::periodic sets EV::PERIODIC and so on, with the exception of I/O
156 events (which can set both EV::READ and EV::WRITE bits), and EV::timer 250 events (which can set both EV::READ and EV::WRITE bits), and EV::timer
157 (which uses EV::TIMEOUT). 251 (which uses EV::TIMEOUT).
158 252
159 In the rare case where one wants to create a watcher but not start it at 253 In the rare case where one wants to create a watcher but not start it at
… …
220 $w->feed_event ($revents) 314 $w->feed_event ($revents)
221 Feed some events on this watcher into EV. EV will react to this call 315 Feed some events on this watcher into EV. EV will react to this call
222 as if the watcher had received the given $revents mask. 316 as if the watcher had received the given $revents mask.
223 317
224 $revents = $w->clear_pending 318 $revents = $w->clear_pending
225 If the watcher is pending, this function returns clears its pending 319 If the watcher is pending, this function clears its pending status
226 status and returns its $revents bitset (as if its callback was 320 and returns its $revents bitset (as if its callback was invoked). If
227 invoked). If the watcher isn't pending it does nothing and returns 321 the watcher isn't pending it does nothing and returns 0.
228 0.
229 322
230 $previous_state = $w->keepalive ($bool) 323 $previous_state = $w->keepalive ($bool)
231 Normally, "EV::loop" will return when there are no active watchers 324 Normally, "EV::loop" will return when there are no active watchers
232 (which is a "deadlock" because no progress can be made anymore). 325 (which is a "deadlock" because no progress can be made anymore).
233 This is convinient because it allows you to start your watchers (and 326 This is convinient because it allows you to start your watchers (and
234 your jobs), call "EV::loop" once and when it returns you know that 327 your jobs), call "EV::loop" once and when it returns you know that
235 all your jobs are finished (or they forgot to register some watchers 328 all your jobs are finished (or they forgot to register some watchers
236 for their task :). 329 for their task :).
237 330
238 Sometimes, however, this gets in your way, for example when you the 331 Sometimes, however, this gets in your way, for example when the
239 module that calls "EV::loop" (usually the main program) is not the 332 module that calls "EV::loop" (usually the main program) is not the
240 same module as a long-living watcher (for example a DNS client 333 same module as a long-living watcher (for example a DNS client
241 module written by somebody else even). Then you might want any 334 module written by somebody else even). Then you might want any
242 outstanding requests to be handled, but you would not want to keep 335 outstanding requests to be handled, but you would not want to keep
243 "EV::loop" from returning just because you happen to have this 336 "EV::loop" from returning just because you happen to have this
… …
245 338
246 In this case you can clear the keepalive status, which means that 339 In this case you can clear the keepalive status, which means that
247 even though your watcher is active, it won't keep "EV::loop" from 340 even though your watcher is active, it won't keep "EV::loop" from
248 returning. 341 returning.
249 342
250 The initial value for keepalive is true (enabled), and you cna 343 The initial value for keepalive is true (enabled), and you can
251 change it any time. 344 change it any time.
252 345
253 Example: Register an I/O watcher for some UDP socket but do not keep 346 Example: Register an I/O watcher for some UDP socket but do not keep
254 the event loop from running just because of that watcher. 347 the event loop from running just because of that watcher.
255 348
256 my $udp_socket = ... 349 my $udp_socket = ...
257 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 350 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
258 $udp_watcher->keepalive (0); 351 $udp_watcher->keepalive (0);
259 352
353 $loop = $w->loop
354 Return the loop that this watcher is attached to.
355
260 WATCHER TYPES 356WATCHER TYPES
261 Each of the following subsections describes a single watcher type. 357 Each of the following subsections describes a single watcher type.
262 358
263 I/O WATCHERS - is this file descriptor readable or writable? 359 I/O WATCHERS - is this file descriptor readable or writable?
264 $w = EV::io $fileno_or_fh, $eventmask, $callback 360 $w = EV::io $fileno_or_fh, $eventmask, $callback
265 $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 361 $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
362 $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
363 $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
266 As long as the returned watcher object is alive, call the $callback 364 As long as the returned watcher object is alive, call the $callback
267 when at least one of events specified in $eventmask occurs. 365 when at least one of events specified in $eventmask occurs.
268 366
269 The $eventmask can be one or more of these constants ORed together: 367 The $eventmask can be one or more of these constants ORed together:
270 368
… …
287 Returns the previously set event mask and optionally set a new one. 385 Returns the previously set event mask and optionally set a new one.
288 386
289 TIMER WATCHERS - relative and optionally repeating timeouts 387 TIMER WATCHERS - relative and optionally repeating timeouts
290 $w = EV::timer $after, $repeat, $callback 388 $w = EV::timer $after, $repeat, $callback
291 $w = EV::timer_ns $after, $repeat, $callback 389 $w = EV::timer_ns $after, $repeat, $callback
390 $w = $loop->timer ($after, $repeat, $callback)
391 $w = $loop->timer_ns ($after, $repeat, $callback)
292 Calls the callback after $after seconds (which may be fractional). 392 Calls the callback after $after seconds (which may be fractional).
293 If $repeat is non-zero, the timer will be restarted (with the 393 If $repeat is non-zero, the timer will be restarted (with the
294 $repeat value as $after) after the callback returns. 394 $repeat value as $after) after the callback returns.
295 395
296 This means that the callback would be called roughly after $after 396 This means that the callback would be called roughly after $after
… …
332 method on the timeout. 432 method on the timeout.
333 433
334 PERIODIC WATCHERS - to cron or not to cron? 434 PERIODIC WATCHERS - to cron or not to cron?
335 $w = EV::periodic $at, $interval, $reschedule_cb, $callback 435 $w = EV::periodic $at, $interval, $reschedule_cb, $callback
336 $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 436 $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
437 $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
438 $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
337 Similar to EV::timer, but is not based on relative timeouts but on 439 Similar to EV::timer, but is not based on relative timeouts but on
338 absolute times. Apart from creating "simple" timers that trigger 440 absolute times. Apart from creating "simple" timers that trigger
339 "at" the specified time, it can also be used for non-drifting 441 "at" the specified time, it can also be used for non-drifting
340 absolute timers and more complex, cron-like, setups that are not 442 absolute timers and more complex, cron-like, setups that are not
341 adversely affected by time jumps (i.e. when the system clock is 443 adversely affected by time jumps (i.e. when the system clock is
342 changed by explicit date -s or other means such as ntpd). It is also 444 changed by explicit date -s or other means such as ntpd). It is also
343 the most complex watcher type in EV. 445 the most complex watcher type in EV.
344 446
345 It has three distinct "modes": 447 It has three distinct "modes":
346 448
347 * absolute timer ($interval = $reschedule_cb = 0) 449 * absolute timer ($interval = $reschedule_cb = 0)
450
348 This time simply fires at the wallclock time $at and doesn't 451 This time simply fires at the wallclock time $at and doesn't
349 repeat. It will not adjust when a time jump occurs, that is, if 452 repeat. It will not adjust when a time jump occurs, that is, if
350 it is to be run at January 1st 2011 then it will run when the 453 it is to be run at January 1st 2011 then it will run when the
351 system time reaches or surpasses this time. 454 system time reaches or surpasses this time.
352 455
353 * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 456 * repeating interval timer ($interval > 0, $reschedule_cb = 0)
457
354 In this mode the watcher will always be scheduled to time out at 458 In this mode the watcher will always be scheduled to time out at
355 the next "$at + N * $interval" time (for some integer N) and 459 the next "$at + N * $interval" time (for some integer N) and
356 then repeat, regardless of any time jumps. 460 then repeat, regardless of any time jumps.
357 461
358 This can be used to create timers that do not drift with respect 462 This can be used to create timers that do not drift with respect
… …
367 Another way to think about it (for the mathematically inclined) 471 Another way to think about it (for the mathematically inclined)
368 is that EV::periodic will try to run the callback in this mode 472 is that EV::periodic will try to run the callback in this mode
369 at the next possible time where "$time = $at (mod $interval)", 473 at the next possible time where "$time = $at (mod $interval)",
370 regardless of any time jumps. 474 regardless of any time jumps.
371 475
372 * manual reschedule mode ($reschedule_cb = coderef) 476 * manual reschedule mode ($reschedule_cb = coderef)
477
373 In this mode $interval and $at are both being ignored. Instead, 478 In this mode $interval and $at are both being ignored. Instead,
374 each time the periodic watcher gets scheduled, the reschedule 479 each time the periodic watcher gets scheduled, the reschedule
375 callback ($reschedule_cb) will be called with the watcher as 480 callback ($reschedule_cb) will be called with the watcher as
376 first, and the current time as second argument. 481 first, and the current time as second argument.
377 482
378 *This callback MUST NOT stop or destroy this or any other 483 *This callback MUST NOT stop or destroy this or any other
484 periodic watcher, ever, and MUST NOT call any event loop
379 periodic watcher, ever*. If you need to stop it, return 1e30 and 485 functions or methods*. If you need to stop it, return 1e30 and
380 stop it afterwards. 486 stop it afterwards. You may create and start a "EV::prepare"
487 watcher for this task.
381 488
382 It must return the next time to trigger, based on the passed 489 It must return the next time to trigger, based on the passed
383 time value (that is, the lowest time value larger than to the 490 time value (that is, the lowest time value larger than or equal
384 second argument). It will usually be called just before the 491 to to the second argument). It will usually be called just
385 callback will be triggered, but might be called at other times, 492 before the callback will be triggered, but might be called at
386 too. 493 other times, too.
387 494
388 This can be used to create very complex timers, such as a timer 495 This can be used to create very complex timers, such as a timer
389 that triggers on each midnight, local time (actually 24 hours 496 that triggers on each midnight, local time (actually 24 hours
390 after the last midnight, to keep the example simple. If you know 497 after the last midnight, to keep the example simple. If you know
391 a way to do it correctly in about the same space (without 498 a way to do it correctly in about the same space (without
… …
438 $old_signum = $w->signal ($new_signal) 545 $old_signum = $w->signal ($new_signal)
439 Returns the previously set signal (always as a number not name) and 546 Returns the previously set signal (always as a number not name) and
440 optionally set a new one. 547 optionally set a new one.
441 548
442 CHILD WATCHERS - watch out for process status changes 549 CHILD WATCHERS - watch out for process status changes
443 $w = EV::child $pid, $callback 550 $w = EV::child $pid, $trace, $callback
444 $w = EV::child_ns $pid, $callback 551 $w = EV::child_ns $pid, $trace, $callback
552 $w = $loop->child ($pid, $trace, $callback)
553 $w = $loop->child_ns ($pid, $trace, $callback)
445 Call the callback when a status change for pid $pid (or any pid if 554 Call the callback when a status change for pid $pid (or any pid if
446 $pid is 0) has been received. More precisely: when the process 555 $pid is 0) has been received (a status change happens when the
556 process terminates or is killed, or, when trace is true,
557 additionally when it is stopped or continued). More precisely: when
447 receives a "SIGCHLD", EV will fetch the outstanding exit/wait status 558 the process receives a "SIGCHLD", EV will fetch the outstanding
448 for all changed/zombie children and call the callback. 559 exit/wait status for all changed/zombie children and call the
560 callback.
449 561
450 It is valid (and fully supported) to install a child watcher after a 562 It is valid (and fully supported) to install a child watcher after a
451 child has exited but before the event loop has started its next 563 child has exited but before the event loop has started its next
452 iteration (for example, first you "fork", then the new child process 564 iteration (for example, first you "fork", then the new child process
453 might exit, and only then do you install a child watcher in the 565 might exit, and only then do you install a child watcher in the
… …
460 be called. 572 be called.
461 573
462 The "child_ns" variant doesn't start (activate) the newly created 574 The "child_ns" variant doesn't start (activate) the newly created
463 watcher. 575 watcher.
464 576
465 $w->set ($pid) 577 $w->set ($pid, $trace)
466 Reconfigures the watcher, see the constructor above for details. Can 578 Reconfigures the watcher, see the constructor above for details. Can
467 be called at any time. 579 be called at any time.
468 580
469 $current_pid = $w->pid 581 $current_pid = $w->pid
470 $old_pid = $w->pid ($new_pid)
471 Returns the previously set process id and optionally set a new one. 582 Returns the previously set process id and optionally set a new one.
472 583
473 $exit_status = $w->rstatus 584 $exit_status = $w->rstatus
474 Return the exit/wait status (as returned by waitpid, see the waitpid 585 Return the exit/wait status (as returned by waitpid, see the waitpid
475 entry in perlfunc). 586 entry in perlfunc).
… …
479 a watcher for all pids). 590 a watcher for all pids).
480 591
481 STAT WATCHERS - did the file attributes just change? 592 STAT WATCHERS - did the file attributes just change?
482 $w = EV::stat $path, $interval, $callback 593 $w = EV::stat $path, $interval, $callback
483 $w = EV::stat_ns $path, $interval, $callback 594 $w = EV::stat_ns $path, $interval, $callback
595 $w = $loop->stat ($path, $interval, $callback)
596 $w = $loop->stat_ns ($path, $interval, $callback)
484 Call the callback when a file status change has been detected on 597 Call the callback when a file status change has been detected on
485 $path. The $path does not need to exist, changing from "path exists" 598 $path. The $path does not need to exist, changing from "path exists"
486 to "path does not exist" is a status change like any other. 599 to "path does not exist" is a status change like any other.
487 600
488 The $interval is a recommended polling interval for systems where 601 The $interval is a recommended polling interval for systems where
… …
548 Can be used to query the actual interval used. 661 Can be used to query the actual interval used.
549 662
550 IDLE WATCHERS - when you've got nothing better to do... 663 IDLE WATCHERS - when you've got nothing better to do...
551 $w = EV::idle $callback 664 $w = EV::idle $callback
552 $w = EV::idle_ns $callback 665 $w = EV::idle_ns $callback
666 $w = $loop->idle ($callback)
667 $w = $loop->idle_ns ($callback)
553 Call the callback when there are no other pending watchers of the 668 Call the callback when there are no other pending watchers of the
554 same or higher priority (excluding check, prepare and other idle 669 same or higher priority (excluding check, prepare and other idle
555 watchers of the same or lower priority, of course). They are called 670 watchers of the same or lower priority, of course). They are called
556 idle watchers because when the watcher is the highest priority 671 idle watchers because when the watcher is the highest priority
557 pending event in the process, the process is considered to be idle 672 pending event in the process, the process is considered to be idle
… …
573 watcher. 688 watcher.
574 689
575 PREPARE WATCHERS - customise your event loop! 690 PREPARE WATCHERS - customise your event loop!
576 $w = EV::prepare $callback 691 $w = EV::prepare $callback
577 $w = EV::prepare_ns $callback 692 $w = EV::prepare_ns $callback
693 $w = $loop->prepare ($callback)
694 $w = $loop->prepare_ns ($callback)
578 Call the callback just before the process would block. You can still 695 Call the callback just before the process would block. You can still
579 create/modify any watchers at this point. 696 create/modify any watchers at this point.
580 697
581 See the EV::check watcher, below, for explanations and an example. 698 See the EV::check watcher, below, for explanations and an example.
582 699
… …
584 watcher. 701 watcher.
585 702
586 CHECK WATCHERS - customise your event loop even more! 703 CHECK WATCHERS - customise your event loop even more!
587 $w = EV::check $callback 704 $w = EV::check $callback
588 $w = EV::check_ns $callback 705 $w = EV::check_ns $callback
706 $w = $loop->check ($callback)
707 $w = $loop->check_ns ($callback)
589 Call the callback just after the process wakes up again (after it 708 Call the callback just after the process wakes up again (after it
590 has gathered events), but before any other callbacks have been 709 has gathered events), but before any other callbacks have been
591 invoked. 710 invoked.
592 711
593 This is used to integrate other event-based software into the EV 712 This is used to integrate other event-based software into the EV
… …
629 # make the dispatcher handle any new stuff 748 # make the dispatcher handle any new stuff
630 ... not shown 749 ... not shown
631 }; 750 };
632 751
633 The callbacks of the created watchers will not be called as the 752 The callbacks of the created watchers will not be called as the
634 watchers are destroyed before this cna happen (remember EV::check 753 watchers are destroyed before this can happen (remember EV::check
635 gets called first). 754 gets called first).
636 755
637 The "check_ns" variant doesn't start (activate) the newly created 756 The "check_ns" variant doesn't start (activate) the newly created
638 watcher. 757 watcher.
639 758
… …
642 is done before the event loop blocks next and before "check" watchers 761 is done before the event loop blocks next and before "check" watchers
643 are being called, and only in the child after the fork. 762 are being called, and only in the child after the fork.
644 763
645 $w = EV::fork $callback 764 $w = EV::fork $callback
646 $w = EV::fork_ns $callback 765 $w = EV::fork_ns $callback
766 $w = $loop->fork ($callback)
767 $w = $loop->fork_ns ($callback)
647 Call the callback before the event loop is resumed in the child 768 Call the callback before the event loop is resumed in the child
648 process after a fork. 769 process after a fork.
649 770
650 The "fork_ns" variant doesn't start (activate) the newly created 771 The "fork_ns" variant doesn't start (activate) the newly created
651 watcher. 772 watcher.
773
774 EMBED WATCHERS - when one backend isn't enough...
775 This is a rather advanced watcher type that lets you embed one event
776 loop into another (currently only IO events are supported in the
777 embedded loop, other types of watchers might be handled in a delayed or
778 incorrect fashion and must not be used).
779
780 See the libev documentation at
781 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code
782 _when_one_backend_> (locally installed as EV::libev) for more details.
783
784 In short, this watcher is most useful on BSD systems without working
785 kqueue to still be able to handle a large number of sockets:
786
787 my $socket_loop;
788
789 # check wether we use SELECT or POLL _and_ KQUEUE is supported
790 if (
791 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
792 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
793 ) {
794 # use kqueue for sockets
795 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
796 }
797
798 # use the default loop otherwise
799 $socket_loop ||= EV::default_loop;
800
801 $w = EV::embed $otherloop[, $callback]
802 $w = EV::embed_ns $otherloop[, $callback]
803 $w = $loop->embed ($otherloop[, $callback])
804 $w = $loop->embed_ns ($otherloop[, $callback])
805 Call the callback when the embedded event loop ($otherloop) has any
806 I/O activity. The $callback is optional: if it is missing, then the
807 embedded event loop will be managed automatically (which is
808 recommended), otherwise you have to invoke "sweep" yourself.
809
810 The "embed_ns" variant doesn't start (activate) the newly created
811 watcher.
812
813 ASYNC WATCHERS - how to wake up another event loop
814 Async watchers are provided by EV, but have little use in perl directly,
815 as perl neither supports threads nor direct access to signal handlers or
816 other contexts where they could be of value.
817
818 It is, however, possible to use them from the XS level.
819
820 Please see the libev documentation for further details.
821
822 $w = EV::async $callback
823 $w = EV::async_ns $callback
824 $w->send
825 $bool = $w->async_pending
652 826
653PERL SIGNALS 827PERL SIGNALS
654 While Perl signal handling (%SIG) is not affected by EV, the behaviour 828 While Perl signal handling (%SIG) is not affected by EV, the behaviour
655 with EV is as the same as any other C library: Perl-signals will only be 829 with EV is as the same as any other C library: Perl-signals will only be
656 handled when Perl runs, which means your signal handler might be invoked 830 handled when Perl runs, which means your signal handler might be invoked
… …
663 to be called on every event loop iteration by installing a "EV::check" 837 to be called on every event loop iteration by installing a "EV::check"
664 watcher: 838 watcher:
665 839
666 my $async_check = EV::check sub { }; 840 my $async_check = EV::check sub { };
667 841
668 This ensures that perl shortly gets into control for a short time, and 842 This ensures that perl gets into control for a short time to handle any
669 also ensures slower overall operation. 843 pending signals, and also ensures (slightly) slower overall operation.
670 844
671THREADS 845THREADS
672 Threads are not supported by this module in any way. Perl pseudo-threads 846 Threads are not supported by this module in any way. Perl pseudo-threads
673 is evil stuff and must die. As soon as Perl gains real threads I will 847 is evil stuff and must die. As soon as Perl gains real threads I will
674 work on thread support for it. 848 work on thread support for it.
… …
689 863
690 On win32, there is no notion of fork so all this doesn't apply, of 864 On win32, there is no notion of fork so all this doesn't apply, of
691 course. 865 course.
692 866
693SEE ALSO 867SEE ALSO
694 EV::ADNS (asynchronous dns), Glib::EV (makes Glib/Gtk2 use EV as event 868 EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event
695 loop), Coro::EV (efficient coroutines with EV). 869 loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines
870 with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop
871 agnostic and portable event driven programming.
696 872
697AUTHOR 873AUTHOR
698 Marc Lehmann <schmorp@schmorp.de> 874 Marc Lehmann <schmorp@schmorp.de>
699 http://home.schmorp.de/ 875 http://home.schmorp.de/
700 876

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines