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

Comparing EV/README (file contents):
Revision 1.12 by root, Tue Nov 27 07:27:10 2007 UTC vs.
Revision 1.48 by root, Fri Jan 24 13:22:22 2020 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
8 # TIMERS
9
10 my $w = EV::timer 2, 0, sub {
11 warn "is called after 2s";
12 };
13
14 my $w = EV::timer 2, 2, sub {
15 warn "is called roughly every 2s (repeat = 2)";
16 };
17
18 undef $w; # destroy event watcher again
19
20 my $w = EV::periodic 0, 60, 0, sub {
21 warn "is called every minute, on the minute, exactly";
22 };
23
24 # IO
25
26 my $w = EV::io *STDIN, EV::READ, sub {
27 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
28 warn "stdin is readable, you entered: ", <STDIN>;
29 };
30
31 # SIGNALS
32
33 my $w = EV::signal 'QUIT', sub {
34 warn "sigquit received\n";
35 };
36
37 # CHILD/PID STATUS CHANGES
7 38
8 # TIMERS 39 my $w = EV::child 666, 0, sub {
40 my ($w, $revents) = @_;
41 my $status = $w->rstatus;
42 };
9 43
10 my $w = EV::timer 2, 0, sub {
11 warn "is called after 2s";
12 };
13
14 my $w = EV::timer 2, 2, sub {
15 warn "is called roughly every 2s (repeat = 2)";
16 };
17
18 undef $w; # destroy event watcher again
19
20 my $w = EV::periodic 0, 60, 0, sub {
21 warn "is called every minute, on the minute, exactly";
22 };
23
24 # IO
25
26 my $w = EV::io *STDIN, EV::READ, sub {
27 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
28 warn "stdin is readable, you entered: ", <STDIN>;
29 };
30
31 # SIGNALS
32
33 my $w = EV::signal 'QUIT', sub {
34 warn "sigquit received\n";
35 };
36
37 # CHILD/PID STATUS CHANGES 44 # STAT CHANGES
38 45 my $w = EV::stat "/etc/passwd", 10, sub {
39 my $w = EV::child 666, sub {
40 my ($w, $revents) = @_; 46 my ($w, $revents) = @_;
41 my $status = $w->rstatus; 47 warn $w->path, " has changed somehow.\n";
42 }; 48 };
43 49
44 # MAINLOOP 50 # MAINLOOP
45 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
46 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
47 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.
48 63
49DESCRIPTION 64DESCRIPTION
50 This module provides an interface to libev 65 This module provides an interface to libev
51 (<http://software.schmorp.de/pkg/libev.html>). While the documentation 66 (<http://software.schmorp.de/pkg/libev.html>). While the documentation
52 below is comprehensive, one might also consult the documentation of 67 below is comprehensive, one might also consult the documentation of
53 libev itself (<http://cvs.schmorp.de/libev/ev.html>) for more subtle 68 libev itself (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
54 details on watcher semantics or some discussion on the available 69 perldoc EV::libev) for more subtle details on watcher semantics or some
55 backends, or how to force a specific backend with "LIBEV_FLAGS". 70 discussion on the available backends, or how to force a specific backend
71 with "LIBEV_FLAGS", or just about in any case because it has much more
72 detailed information.
73
74 This module is very fast and scalable. It is actually so fast that you
75 can use it through the AnyEvent module, stay portable to other event
76 loops (if you don't rely on any watcher types not available through it)
77 and still be faster than with any other event loop currently supported
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.
112
113EVENT LOOPS
114 EV supports multiple event loops: There is a single "default event loop"
115 that can handle everything including signals and child watchers, and any
116 number of "dynamic event loops" that can use different backends (with
117 various limitations), but no child and signal watchers.
118
119 You do not have to do anything to create the default event loop: When
120 the module is loaded a suitable backend is selected on the premise of
121 selecting a working backend (which for example rules out kqueue on most
122 BSDs). Modules should, unless they have "special needs" always use the
123 default loop as this is fastest (perl-wise), best supported by other
124 modules (e.g. AnyEvent or Coro) and most portable event loop.
125
126 For specific programs you can create additional event loops dynamically.
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
135 $loop = new EV::Loop [$flags]
136 Create a new event loop as per the specified flags. Please refer to
137 the "ev_loop_new ()" function description in the libev documentation
138 (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI
139 ONS>, or locally-installed as EV::libev manpage) for more info.
140
141 The loop will automatically be destroyed when it is no longer
142 referenced by any watcher and the loop object goes out of scope.
143
144 If you are not embedding the loop, then Using "EV::FLAG_FORKCHECK"
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.
149
150 $loop->loop_fork
151 Must be called after a fork in the child, before entering or
152 continuing the event loop. An alternative is to use
153 "EV::FLAG_FORKCHECK" which calls this function automatically, at
154 some performance loss (refer to the libev documentation).
155
156 $loop->verify
157 Calls "ev_verify" to make internal consistency checks (for debugging
158 libev) and abort the program if any data structures were found to be
159 corrupted.
160
161 $loop = EV::default_loop [$flags]
162 Return the default loop (which is a singleton object). Since this
163 module already creates the default loop with default flags,
164 specifying flags here will not have any effect unless you destroy
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.
56 167
57BASIC INTERFACE 168BASIC INTERFACE
58 $EV::DIED 169 $EV::DIED
59 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
60 callback throws an exception (with $@ containing thr error). The 171 callback throws an exception (with $@ containing the error). The
61 default prints an informative message and continues. 172 default prints an informative message and continues.
62 173
63 If this callback throws an exception it will be silently ignored. 174 If this callback throws an exception it will be silently ignored.
175
176 $flags = EV::supported_backends
177 $flags = EV::recommended_backends
178 $flags = EV::embeddable_backends
179 Returns the set (see "EV::BACKEND_*" flags) of backends supported by
180 this instance of EV, the set of recommended backends (supposed to be
181 good) for this platform and the set of embeddable backends (see
182 EMBED WATCHERS).
183
184 EV::sleep $seconds
185 Block the process for the given number of (fractional) seconds.
64 186
65 $time = EV::time 187 $time = EV::time
66 Returns the current time in (fractional) seconds since the epoch. 188 Returns the current time in (fractional) seconds since the epoch.
67 189
68 $time = EV::now 190 $time = EV::now
191 $time = $loop->now
69 Returns the time the last event loop iteration has been started. 192 Returns the time the last event loop iteration has been started.
70 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
71 to it is usually faster then calling EV::time. 194 to it is usually faster then calling EV::time.
72 195
73 $method = EV::method 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::run".
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").
232
233 $backend = EV::backend
234 $backend = $loop->backend
74 Returns an integer describing the backend used by libev 235 Returns an integer describing the backend used by libev
75 (EV::METHOD_SELECT or EV::METHOD_EPOLL). 236 (EV::BACKEND_SELECT or EV::BACKEND_EPOLL).
76 237
77 EV::loop [$flags] 238 $active = EV::run [$flags]
239 $active = $loop->run ([$flags])
78 Begin checking for events and calling callbacks. It returns when a 240 Begin checking for events and calling callbacks. It returns when a
79 callback calls EV::unloop. 241 callback calls EV::break or the flags 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 return value can generally be interpreted
245 as "if true, there is more work left to do".
80 246
81 The $flags argument can be one of the following: 247 The $flags argument can be one of the following:
82 248
83 0 as above 249 0 as above
84 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 250 EV::RUN_ONCE block at most once (wait, but do not loop)
85 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 251 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
86 252
87 EV::unloop [$how] 253 EV::break [$how]
254 $loop->break ([$how])
88 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
89 makes the innermost call to EV::loop return. 256 the innermost call to EV::run return.
90 257
91 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::run
92 EV::loop will return as fast as possible. 259 will return as fast as possible.
260
261 When called with an argument of EV::BREAK_CANCEL, any pending break
262 will be cancelled.
263
264 $count = EV::iteration
265 $count = $loop->iteration
266 Return the number of times the event loop has polled for new events.
267 Sometimes useful as a generation counter.
93 268
94 EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 269 EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
270 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
95 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
96 one-shot event without the need for managing a watcher object. 272 one-shot event without the need for managing a watcher object.
97 273
98 If $fh_or_undef is a filehandle or file descriptor, then $events 274 If $fh_or_undef is a filehandle or file descriptor, then $events
99 must be a bitset containing either "EV::READ", "EV::WRITE" or 275 must be a bitset containing either "EV::READ", "EV::WRITE" or
100 "EV::READ | EV::WRITE", indicating the type of I/O event you want to 276 "EV::READ | EV::WRITE", indicating the type of I/O event you want to
101 wait for. If you do not want to wait for some I/O event, specify 277 wait for. If you do not want to wait for some I/O event, specify
102 "undef" for $fh_or_undef and 0 for $events). 278 "undef" for $fh_or_undef and 0 for $events).
103 279
104 If timeout is "undef" or negative, then there will be no timeout. 280 If timeout is "undef" or negative, then there will be no timeout.
105 Otherwise a EV::timer with this value will be started. 281 Otherwise an "EV::timer" with this value will be started.
106 282
107 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,
108 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
109 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",
110 "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). 286 "EV::READ", "EV::WRITE" and "EV::TIMER").
111 287
112 EV::once doesn't return anything: the watchers stay active till 288 EV::once doesn't return anything: the watchers stay active till
113 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
114 the callback invoked. 290 the callback invoked.
115 291
116 WATCHER 292 EV::feed_fd_event $fd, $revents
293 $loop->feed_fd_event ($fd, $revents)
294 Feed an event on a file descriptor into EV. EV will react to this
295 call as if the readyness notifications specified by $revents (a
296 combination of "EV::READ" and "EV::WRITE") happened on the file
297 descriptor $fd.
298
299 EV::feed_signal_event $signal
300 Feed a signal event into the default loop. EV will react to this
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 for custom signal implementations.
307
308 EV::set_io_collect_interval $time
309 $loop->set_io_collect_interval ($time)
310 EV::set_timeout_collect_interval $time
311 $loop->set_timeout_collect_interval ($time)
312 These advanced functions set the minimum block interval when polling
313 for I/O events and the minimum wait interval for timer events. See
314 the libev documentation at
315 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT
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.
326
327WATCHER OBJECTS
117 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
118 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,
119 you would create an EV::io watcher for that: 330 you would create an EV::io watcher for that:
120 331
121 my $watcher = EV::io *STDIN, EV::READ, sub { 332 my $watcher = EV::io *STDIN, EV::READ, sub {
122 my ($watcher, $revents) = @_; 333 my ($watcher, $revents) = @_;
123 warn "yeah, STDIN should not be readable without blocking!\n" 334 warn "yeah, STDIN should now be readable without blocking!\n"
124 }; 335 };
125 336
126 All watchers can be active (waiting for events) or inactive (paused). 337 All watchers can be active (waiting for events) or inactive (paused).
127 Only active watchers will have their callbacks invoked. All callbacks 338 Only active watchers will have their callbacks invoked. All callbacks
128 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
129 received events. 340 received events.
130 341
131 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
132 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
133 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,
134 EV::periodic sets EV::PERIODIC and so on, with the exception of IO 345 EV::periodic sets EV::PERIODIC and so on, with the exception of I/O
135 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).
136 (which uses EV::TIMEOUT).
137 347
138 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
139 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
140 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.
141 351
… …
145 355
146 Also, all methods changing some aspect of a watcher (->set, ->priority, 356 Also, all methods changing some aspect of a watcher (->set, ->priority,
147 ->fh and so on) automatically stop and start it again if it is active, 357 ->fh and so on) automatically stop and start it again if it is active,
148 which means pending events get lost. 358 which means pending events get lost.
149 359
150 WATCHER TYPES 360 COMMON WATCHER METHODS
151 Now lets move to the existing watcher types and asociated methods. 361 This section lists methods common to all watchers.
152
153 The following methods are available for all watchers. Then followes a
154 description of each watcher constructor (EV::io, EV::timer,
155 EV::periodic, EV::signal, EV::child, EV::idle, EV::prepare and
156 EV::check), followed by any type-specific methods (if any).
157 362
158 $w->start 363 $w->start
159 Starts a watcher if it isn't active already. Does nothing to an 364 Starts a watcher if it isn't active already. Does nothing to an
160 already active watcher. By default, all watchers start out in the 365 already active watcher. By default, all watchers start out in the
161 active state (see the description of the "_ns" variants if you need 366 active state (see the description of the "_ns" variants if you need
162 stopped watchers). 367 stopped watchers).
163 368
164 $w->stop 369 $w->stop
165 Stop a watcher if it is active. Also clear any pending events 370 Stop a watcher if it is active. Also clear any pending events
166 (events that have been received but that didn't yet result in a 371 (events that have been received but that didn't yet result in a
167 callback invocation), regardless of wether the watcher was active or 372 callback invocation), regardless of whether the watcher was active
168 not. 373 or not.
169 374
170 $bool = $w->is_active 375 $bool = $w->is_active
171 Returns true if the watcher is active, false otherwise. 376 Returns true if the watcher is active, false otherwise.
172 377
173 $current_data = $w->data 378 $current_data = $w->data
… …
196 The default priority of any newly-created watcher is 0. 401 The default priority of any newly-created watcher is 0.
197 402
198 Note that the priority semantics have not yet been fleshed out and 403 Note that the priority semantics have not yet been fleshed out and
199 are subject to almost certain change. 404 are subject to almost certain change.
200 405
201 $w->trigger ($revents) 406 $w->invoke ($revents)
202 Call the callback *now* with the given event mask. 407 Call the callback *now* with the given event mask.
203 408
409 $w->feed_event ($revents)
410 Feed some events on this watcher into EV. EV will react to this call
411 as if the watcher had received the given $revents mask.
412
413 $revents = $w->clear_pending
414 If the watcher is pending, this function clears its pending status
415 and returns its $revents bitset (as if its callback was invoked). If
416 the watcher isn't pending it does nothing and returns 0.
417
204 $previous_state = $w->keepalive ($bool) 418 $previous_state = $w->keepalive ($bool)
205 Normally, "EV::loop" will return when there are no active watchers 419 Normally, "EV::run" will return when there are no active watchers
206 (which is a "deadlock" because no progress can be made anymore). 420 (which is a "deadlock" because no progress can be made anymore).
207 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
208 your jobs), call "EV::loop" once and when it returns you know that 422 your jobs), call "EV::run" once and when it returns you know that
209 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
210 for their task :). 424 for their task :).
211 425
212 Sometimes, however, this gets in your way, for example when you the 426 Sometimes, however, this gets in your way, for example when the
213 module that calls "EV::loop" (usually the main program) is not the 427 module that calls "EV::run" (usually the main program) is not the
214 same module as a long-living watcher (for example a DNS client 428 same module as a long-living watcher (for example a DNS client
215 module written by somebody else even). Then you might want any 429 module written by somebody else even). Then you might want any
216 outstanding requests to be handled, but you would not want to keep 430 outstanding requests to be handled, but you would not want to keep
217 "EV::loop" from returning just because you happen to have this 431 "EV::run" from returning just because you happen to have this
218 long-running UDP port watcher. 432 long-running UDP port watcher.
219 433
220 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
221 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::run" from
222 returning. 436 returning.
223 437
224 The initial value for keepalive is true (enabled), and you cna 438 The initial value for keepalive is true (enabled), and you can
225 change it any time. 439 change it any time.
226 440
227 Example: Register an IO watcher for some UDP socket but do not keep 441 Example: Register an I/O watcher for some UDP socket but do not keep
228 the event loop from running just because of that watcher. 442 the event loop from running just because of that watcher.
229 443
230 my $udp_socket = ... 444 my $udp_socket = ...
231 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 445 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
232 $udp_watcher->keepalive (0); 446 $udp_watcher->keepalive (0);
233 447
448 $loop = $w->loop
449 Return the loop that this watcher is attached to.
450
451WATCHER TYPES
452 Each of the following subsections describes a single watcher type.
453
454 I/O WATCHERS - is this file descriptor readable or writable?
234 $w = EV::io $fileno_or_fh, $eventmask, $callback 455 $w = EV::io $fileno_or_fh, $eventmask, $callback
235 $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 456 $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
457 $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
458 $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
236 As long as the returned watcher object is alive, call the $callback 459 As long as the returned watcher object is alive, call the $callback
237 when the events specified in $eventmask. 460 when at least one of events specified in $eventmask occurs.
238 461
239 The $eventmask can be one or more of these constants ORed together: 462 The $eventmask can be one or more of these constants ORed together:
240 463
241 EV::READ wait until read() wouldn't block anymore 464 EV::READ wait until read() wouldn't block anymore
242 EV::WRITE wait until write() wouldn't block anymore 465 EV::WRITE wait until write() wouldn't block anymore
… …
254 477
255 $current_eventmask = $w->events 478 $current_eventmask = $w->events
256 $old_eventmask = $w->events ($new_eventmask) 479 $old_eventmask = $w->events ($new_eventmask)
257 Returns the previously set event mask and optionally set a new one. 480 Returns the previously set event mask and optionally set a new one.
258 481
482 TIMER WATCHERS - relative and optionally repeating timeouts
259 $w = EV::timer $after, $repeat, $callback 483 $w = EV::timer $after, $repeat, $callback
260 $w = EV::timer_ns $after, $repeat, $callback 484 $w = EV::timer_ns $after, $repeat, $callback
485 $w = $loop->timer ($after, $repeat, $callback)
486 $w = $loop->timer_ns ($after, $repeat, $callback)
261 Calls the callback after $after seconds (which may be fractional). 487 Calls the callback after $after seconds (which may be fractional or
262 If $repeat is non-zero, the timer will be restarted (with the 488 negative). If $repeat is non-zero, the timer will be restarted (with
263 $repeat value as $after) after the callback returns. 489 the $repeat value as $after) after the callback returns.
264 490
265 This means that the callback would be called roughly after $after 491 This means that the callback would be called roughly after $after
266 seconds, and then every $repeat seconds. The timer does his best not 492 seconds, and then every $repeat seconds. The timer does his best not
267 to drift, but it will not invoke the timer more often then once per 493 to drift, but it will not invoke the timer more often then once per
268 event loop iteration, and might drift in other cases. If that isn't 494 event loop iteration, and might drift in other cases. If that isn't
… …
275 the same time. 501 the same time.
276 502
277 The "timer_ns" variant doesn't start (activate) the newly created 503 The "timer_ns" variant doesn't start (activate) the newly created
278 watcher. 504 watcher.
279 505
280 $w->set ($after, $repeat) 506 $w->set ($after, $repeat = 0)
281 Reconfigures the watcher, see the constructor above for details. Can 507 Reconfigures the watcher, see the constructor above for details. Can
282 be at any time. 508 be called at any time.
283 509
284 $w->again 510 $w->again
511 $w->again ($repeat)
285 Similar to the "start" method, but has special semantics for 512 Similar to the "start" method, but has special semantics for
286 repeating timers: 513 repeating timers:
287 514
288 If the timer is active and non-repeating, it will be stopped. 515 If the timer is active and non-repeating, it will be stopped.
289 516
… …
298 This behaviour is useful when you have a timeout for some IO 525 This behaviour is useful when you have a timeout for some IO
299 operation. You create a timer object with the same value for $after 526 operation. You create a timer object with the same value for $after
300 and $repeat, and then, in the read/write watcher, run the "again" 527 and $repeat, and then, in the read/write watcher, run the "again"
301 method on the timeout. 528 method on the timeout.
302 529
530 If called with a $repeat argument, then it uses this a timer repeat
531 value.
532
533 $after = $w->remaining
534 Calculates and returns the remaining time till the timer will fire.
535
536 $repeat = $w->repeat
537 $old_repeat = $w->repeat ($new_repeat)
538 Returns the current value of the repeat attribute and optionally
539 sets a new one. Setting the new one will not restart the watcher -
540 if the watcher is active, the new repeat value is used whenever it
541 expires next.
542
543 PERIODIC WATCHERS - to cron or not to cron?
303 $w = EV::periodic $at, $interval, $reschedule_cb, $callback 544 $w = EV::periodic $at, $interval, $reschedule_cb, $callback
304 $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 545 $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
546 $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
547 $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
305 Similar to EV::timer, but is not based on relative timeouts but on 548 Similar to EV::timer, but is not based on relative timeouts but on
306 absolute times. Apart from creating "simple" timers that trigger 549 absolute times. Apart from creating "simple" timers that trigger
307 "at" the specified time, it can also be used for non-drifting 550 "at" the specified time, it can also be used for non-drifting
308 absolute timers and more complex, cron-like, setups that are not 551 absolute timers and more complex, cron-like, setups that are not
309 adversely affected by time jumps (i.e. when the system clock is 552 adversely affected by time jumps (i.e. when the system clock is
310 changed by explicit date -s or other means such as ntpd). It is also 553 changed by explicit date -s or other means such as ntpd). It is also
311 the most complex watcher type in EV. 554 the most complex watcher type in EV.
312 555
313 It has three distinct "modes": 556 It has three distinct "modes":
314 557
315 * absolute timer ($interval = $reschedule_cb = 0) 558 * absolute timer ($interval = $reschedule_cb = 0)
559
316 This time simply fires at the wallclock time $at and doesn't 560 This time simply fires at the wallclock time $at and doesn't
317 repeat. It will not adjust when a time jump occurs, that is, if 561 repeat. It will not adjust when a time jump occurs, that is, if
318 it is to be run at January 1st 2011 then it will run when the 562 it is to be run at January 1st 2011 then it will run when the
319 system time reaches or surpasses this time. 563 system time reaches or surpasses this time.
320 564
321 * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 565 * repeating interval timer ($interval > 0, $reschedule_cb = 0)
566
322 In this mode the watcher will always be scheduled to time out at 567 In this mode the watcher will always be scheduled to time out at
323 the next "$at + N * $interval" time (for some integer N) and 568 the next "$at + N * $interval" time (for the lowest integer N)
324 then repeat, regardless of any time jumps. 569 and then repeat, regardless of any time jumps. Note that, since
570 "N" can be negative, the first trigger can happen before $at.
325 571
326 This can be used to create timers that do not drift with respect 572 This can be used to create timers that do not drift with respect
327 to system time: 573 to system time:
328 574
329 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; 575 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
330 576
331 That doesn't mean there will always be 3600 seconds in between 577 That doesn't mean there will always be 3600 seconds in between
332 triggers, but only that the the clalback will be called when the 578 triggers, but only that the the callback will be called when the
333 system time shows a full hour (UTC). 579 system time shows a full hour (UTC).
334 580
335 Another way to think about it (for the mathematically inclined) 581 Another way to think about it (for the mathematically inclined)
336 is that EV::periodic will try to run the callback in this mode 582 is that EV::periodic will try to run the callback in this mode
337 at the next possible time where "$time = $at (mod $interval)", 583 at the next possible time where "$time = $at (mod $interval)",
338 regardless of any time jumps. 584 regardless of any time jumps.
339 585
340 * manual reschedule mode ($reschedule_cb = coderef) 586 * manual reschedule mode ($reschedule_cb = coderef)
587
341 In this mode $interval and $at are both being ignored. Instead, 588 In this mode $interval and $at are both being ignored. Instead,
342 each time the periodic watcher gets scheduled, the reschedule 589 each time the periodic watcher gets scheduled, the reschedule
343 callback ($reschedule_cb) will be called with the watcher as 590 callback ($reschedule_cb) will be called with the watcher as
344 first, and the current time as second argument. 591 first, and the current time as second argument.
345 592
346 *This callback MUST NOT stop or destroy this or any other 593 *This callback MUST NOT stop or destroy this or any other
594 periodic watcher, ever, and MUST NOT call any event loop
347 periodic watcher, ever*. If you need to stop it, return 1e30 and 595 functions or methods*. If you need to stop it, return 1e30 and
348 stop it afterwards. 596 stop it afterwards. You may create and start an "EV::prepare"
597 watcher for this task.
349 598
350 It must return the next time to trigger, based on the passed 599 It must return the next time to trigger, based on the passed
351 time value (that is, the lowest time value larger than to the 600 time value (that is, the lowest time value larger than or equal
352 second argument). It will usually be called just before the 601 to to the second argument). It will usually be called just
353 callback will be triggered, but might be called at other times, 602 before the callback will be triggered, but might be called at
354 too. 603 other times, too.
355 604
356 This can be used to create very complex timers, such as a timer 605 This can be used to create very complex timers, such as a timer
357 that triggers on each midnight, local time (actually 24 hours 606 that triggers on each midnight, local time (actually one day
358 after the last midnight, to keep the example simple. If you know 607 after the last midnight, to keep the example simple):
359 a way to do it correctly in about the same space (without
360 requiring elaborate modules), drop me a note :):
361 608
362 my $daily = EV::periodic 0, 0, sub { 609 my $daily = EV::periodic 0, 0, sub {
363 my ($w, $now) = @_; 610 my ($w, $now) = @_;
364 611
365 use Time::Local (); 612 use Time::Local ();
366 my (undef, undef, undef, $d, $m, $y) = localtime $now; 613 my (undef, undef, undef, $d, $m, $y) = localtime $now;
367 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y 614 Time::Local::timelocal_nocheck 0, 0, 0, $d + 1, $m, $y
368 }, sub { 615 }, sub {
369 print "it's midnight or likely shortly after, now\n"; 616 print "it's midnight or likely shortly after, now\n";
370 }; 617 };
371 618
372 The "periodic_ns" variant doesn't start (activate) the newly created 619 The "periodic_ns" variant doesn't start (activate) the newly created
373 watcher. 620 watcher.
374 621
375 $w->set ($at, $interval, $reschedule_cb) 622 $w->set ($at, $interval, $reschedule_cb)
376 Reconfigures the watcher, see the constructor above for details. Can 623 Reconfigures the watcher, see the constructor above for details. Can
377 be at any time. 624 be called at any time.
378 625
379 $w->again 626 $w->again
380 Simply stops and starts the watcher again. 627 Simply stops and starts the watcher again.
381 628
629 $time = $w->at
630 Return the time that the watcher is expected to trigger next.
631
632 $offset = $w->offset
633 $old_offset = $w->offset ($new_offset)
634 Returns the current value of the offset attribute and optionally
635 sets a new one. Setting the new one will not restart the watcher -
636 if the watcher is active, the new offset value is used whenever it
637 expires next.
638
639 $interval = $w->interval
640 $old_interval = $w->interval ($new_interval)
641 See above, for the interval attribute.
642
643 $reschedule_cb = $w->reschedule_cb
644 $old_reschedule_cb = $w->reschedule_cb ($new_reschedule_cb)
645 See above, for the reschedule callback.
646
647 SIGNAL WATCHERS - signal me when a signal gets signalled!
382 $w = EV::signal $signal, $callback 648 $w = EV::signal $signal, $callback
383 $w = EV::signal_ns $signal, $callback 649 $w = EV::signal_ns $signal, $callback
650 $w = $loop->signal ($signal, $callback)
651 $w = $loop->signal_ns ($signal, $callback)
384 Call the callback when $signal is received (the signal can be 652 Call the callback when $signal is received (the signal can be
385 specified by number or by name, just as with kill or %SIG). 653 specified by number or by name, just as with "kill" or %SIG).
654
655 Only one event loop can grab a given signal - attempting to grab the
656 same signal from two EV loops will crash the program immediately or
657 cause data corruption.
386 658
387 EV will grab the signal for the process (the kernel only allows one 659 EV will grab the signal for the process (the kernel only allows one
388 component to receive a signal at a time) when you start a signal 660 component to receive a signal at a time) when you start a signal
389 watcher, and removes it again when you stop it. Perl does the same 661 watcher, and removes it again when you stop it. Perl does the same
390 when you add/remove callbacks to %SIG, so watch out. 662 when you add/remove callbacks to %SIG, so watch out.
… …
394 The "signal_ns" variant doesn't start (activate) the newly created 666 The "signal_ns" variant doesn't start (activate) the newly created
395 watcher. 667 watcher.
396 668
397 $w->set ($signal) 669 $w->set ($signal)
398 Reconfigures the watcher, see the constructor above for details. Can 670 Reconfigures the watcher, see the constructor above for details. Can
399 be at any time. 671 be called at any time.
400 672
401 $current_signum = $w->signal 673 $current_signum = $w->signal
402 $old_signum = $w->signal ($new_signal) 674 $old_signum = $w->signal ($new_signal)
403 Returns the previously set signal (always as a number not name) and 675 Returns the previously set signal (always as a number not name) and
404 optionally set a new one. 676 optionally set a new one.
405 677
678 CHILD WATCHERS - watch out for process status changes
406 $w = EV::child $pid, $callback 679 $w = EV::child $pid, $trace, $callback
407 $w = EV::child_ns $pid, $callback 680 $w = EV::child_ns $pid, $trace, $callback
681 $w = $loop->child ($pid, $trace, $callback)
682 $w = $loop->child_ns ($pid, $trace, $callback)
408 Call the callback when a status change for pid $pid (or any pid if 683 Call the callback when a status change for pid $pid (or any pid if
409 $pid is 0) has been received. More precisely: when the process 684 $pid is 0) has been received (a status change happens when the
685 process terminates or is killed, or, when trace is true,
686 additionally when it is stopped or continued). More precisely: when
410 receives a SIGCHLD, EV will fetch the outstanding exit/wait status 687 the process receives a "SIGCHLD", EV will fetch the outstanding
411 for all changed/zombie children and call the callback. 688 exit/wait status for all changed/zombie children and call the
689 callback.
412 690
413 You can access both status and pid by using the "rstatus" and "rpid" 691 It is valid (and fully supported) to install a child watcher after a
692 child has exited but before the event loop has started its next
693 iteration (for example, first you "fork", then the new child process
694 might exit, and only then do you install a child watcher in the
695 parent for the new pid).
696
697 You can access both exit (or tracing) status and pid by using the
414 methods on the watcher object. 698 "rstatus" and "rpid" methods on the watcher object.
415 699
416 You can have as many pid watchers per pid as you want. 700 You can have as many pid watchers per pid as you want, they will all
701 be called.
417 702
418 The "child_ns" variant doesn't start (activate) the newly created 703 The "child_ns" variant doesn't start (activate) the newly created
419 watcher. 704 watcher.
420 705
421 $w->set ($pid) 706 $w->set ($pid, $trace)
422 Reconfigures the watcher, see the constructor above for details. Can 707 Reconfigures the watcher, see the constructor above for details. Can
423 be at any time. 708 be called at any time.
424 709
425 $current_pid = $w->pid 710 $current_pid = $w->pid
426 $old_pid = $w->pid ($new_pid)
427 Returns the previously set process id and optionally set a new one. 711 Returns the previously set process id and optionally set a new one.
428 712
429 $exit_status = $w->rstatus 713 $exit_status = $w->rstatus
430 Return the exit/wait status (as returned by waitpid, see the waitpid 714 Return the exit/wait status (as returned by waitpid, see the waitpid
431 entry in perlfunc). 715 entry in perlfunc).
432 716
433 $pid = $w->rpid 717 $pid = $w->rpid
434 Return the pid of the awaited child (useful when you have installed 718 Return the pid of the awaited child (useful when you have installed
435 a watcher for all pids). 719 a watcher for all pids).
436 720
721 STAT WATCHERS - did the file attributes just change?
722 $w = EV::stat $path, $interval, $callback
723 $w = EV::stat_ns $path, $interval, $callback
724 $w = $loop->stat ($path, $interval, $callback)
725 $w = $loop->stat_ns ($path, $interval, $callback)
726 Call the callback when a file status change has been detected on
727 $path. The $path does not need to exist, changing from "path exists"
728 to "path does not exist" is a status change like any other.
729
730 The $interval is a recommended polling interval for systems where
731 OS-supported change notifications don't exist or are not supported.
732 If you use 0 then an unspecified default is used (which is highly
733 recommended!), which is to be expected to be around five seconds
734 usually.
735
736 This watcher type is not meant for massive numbers of stat watchers,
737 as even with OS-supported change notifications, this can be
738 resource-intensive.
739
740 The "stat_ns" variant doesn't start (activate) the newly created
741 watcher.
742
743 ... = $w->stat
744 This call is very similar to the perl "stat" built-in: It stats
745 (using "lstat") the path specified in the watcher and sets perls
746 stat cache (as well as EV's idea of the current stat values) to the
747 values found.
748
749 In scalar context, a boolean is return indicating success or failure
750 of the stat. In list context, the same 13-value list as with stat is
751 returned (except that the blksize and blocks fields are not
752 reliable).
753
754 In the case of an error, errno is set to "ENOENT" (regardless of the
755 actual error value) and the "nlink" value is forced to zero (if the
756 stat was successful then nlink is guaranteed to be non-zero).
757
758 See also the next two entries for more info.
759
760 ... = $w->attr
761 Just like "$w->stat", but without the initial stat'ing: this returns
762 the values most recently detected by EV. See the next entry for more
763 info.
764
765 ... = $w->prev
766 Just like "$w->stat", but without the initial stat'ing: this returns
767 the previous set of values, before the change.
768
769 That is, when the watcher callback is invoked, "$w->prev" will be
770 set to the values found *before* a change was detected, while
771 "$w->attr" returns the values found leading to the change detection.
772 The difference (if any) between "prev" and "attr" is what triggered
773 the callback.
774
775 If you did something to the filesystem object and do not want to
776 trigger yet another change, you can call "stat" to update EV's idea
777 of what the current attributes are.
778
779 $w->set ($path, $interval)
780 Reconfigures the watcher, see the constructor above for details. Can
781 be called at any time.
782
783 $current_path = $w->path
784 $old_path = $w->path ($new_path)
785 Returns the previously set path and optionally set a new one.
786
787 $current_interval = $w->interval
788 $old_interval = $w->interval ($new_interval)
789 Returns the previously set interval and optionally set a new one.
790 Can be used to query the actual interval used.
791
792 IDLE WATCHERS - when you've got nothing better to do...
437 $w = EV::idle $callback 793 $w = EV::idle $callback
438 $w = EV::idle_ns $callback 794 $w = EV::idle_ns $callback
795 $w = $loop->idle ($callback)
796 $w = $loop->idle_ns ($callback)
439 Call the callback when there are no pending io, timer/periodic, 797 Call the callback when there are no other pending watchers of the
440 signal or child events, i.e. when the process is idle. 798 same or higher priority (excluding check, prepare and other idle
799 watchers of the same or lower priority, of course). They are called
800 idle watchers because when the watcher is the highest priority
801 pending event in the process, the process is considered to be idle
802 at that priority.
803
804 If you want a watcher that is only ever called when *no* other
805 events are outstanding you have to set the priority to "EV::MINPRI".
441 806
442 The process will not block as long as any idle watchers are active, 807 The process will not block as long as any idle watchers are active,
443 and they will be called repeatedly until stopped. 808 and they will be called repeatedly until stopped.
444 809
810 For example, if you have idle watchers at priority 0 and 1, and an
811 I/O watcher at priority 0, then the idle watcher at priority 1 and
812 the I/O watcher will always run when ready. Only when the idle
813 watcher at priority 1 is stopped and the I/O watcher at priority 0
814 is not pending with the 0-priority idle watcher be invoked.
815
445 The "idle_ns" variant doesn't start (activate) the newly created 816 The "idle_ns" variant doesn't start (activate) the newly created
446 watcher. 817 watcher.
447 818
819 PREPARE WATCHERS - customise your event loop!
448 $w = EV::prepare $callback 820 $w = EV::prepare $callback
449 $w = EV::prepare_ns $callback 821 $w = EV::prepare_ns $callback
822 $w = $loop->prepare ($callback)
823 $w = $loop->prepare_ns ($callback)
450 Call the callback just before the process would block. You can still 824 Call the callback just before the process would block. You can still
451 create/modify any watchers at this point. 825 create/modify any watchers at this point.
452 826
453 See the EV::check watcher, below, for explanations and an example. 827 See the EV::check watcher, below, for explanations and an example.
454 828
455 The "prepare_ns" variant doesn't start (activate) the newly created 829 The "prepare_ns" variant doesn't start (activate) the newly created
456 watcher. 830 watcher.
457 831
832 CHECK WATCHERS - customise your event loop even more!
458 $w = EV::check $callback 833 $w = EV::check $callback
459 $w = EV::check_ns $callback 834 $w = EV::check_ns $callback
835 $w = $loop->check ($callback)
836 $w = $loop->check_ns ($callback)
460 Call the callback just after the process wakes up again (after it 837 Call the callback just after the process wakes up again (after it
461 has gathered events), but before any other callbacks have been 838 has gathered events), but before any other callbacks have been
462 invoked. 839 invoked.
463 840
464 This is used to integrate other event-based software into the EV 841 This can be used to integrate other event-based software into the EV
465 mainloop: You register a prepare callback and in there, you create 842 mainloop: You register a prepare callback and in there, you create
466 io and timer watchers as required by the other software. Here is a 843 io and timer watchers as required by the other software. Here is a
467 real-world example of integrating Net::SNMP (with some details left 844 real-world example of integrating Net::SNMP (with some details left
468 out): 845 out):
469 846
… …
475 or return; 852 or return;
476 853
477 # make the dispatcher handle any outstanding stuff 854 # make the dispatcher handle any outstanding stuff
478 ... not shown 855 ... not shown
479 856
480 # create an IO watcher for each and every socket 857 # create an I/O watcher for each and every socket
481 @snmp_watcher = ( 858 @snmp_watcher = (
482 (map { EV::io $_, EV::READ, sub { } } 859 (map { EV::io $_, EV::READ, sub { } }
483 keys %{ $dispatcher->{_descriptors} }), 860 keys %{ $dispatcher->{_descriptors} }),
484 861
485 EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] 862 EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
… …
500 # make the dispatcher handle any new stuff 877 # make the dispatcher handle any new stuff
501 ... not shown 878 ... not shown
502 }; 879 };
503 880
504 The callbacks of the created watchers will not be called as the 881 The callbacks of the created watchers will not be called as the
505 watchers are destroyed before this cna happen (remember EV::check 882 watchers are destroyed before this can happen (remember EV::check
506 gets called first). 883 gets called first).
507 884
508 The "check_ns" variant doesn't start (activate) the newly created 885 The "check_ns" variant doesn't start (activate) the newly created
509 watcher. 886 watcher.
510 887
888 EV::CHECK constant issues
889 Like all other watcher types, there is a bitmask constant for use in
890 $revents and other places. The "EV::CHECK" is special as it has the
891 same name as the "CHECK" sub called by Perl. This doesn't cause big
892 issues on newer perls (beginning with 5.8.9), but it means thatthe
893 constant must be *inlined*, i.e. runtime calls will not work. That
894 means that as long as you always "use EV" and then "EV::CHECK" you
895 are on the safe side.
896
897 FORK WATCHERS - the audacity to resume the event loop after a fork
898 Fork watchers are called when a "fork ()" was detected. The invocation
899 is done before the event loop blocks next and before "check" watchers
900 are being called, and only in the child after the fork.
901
902 $w = EV::fork $callback
903 $w = EV::fork_ns $callback
904 $w = $loop->fork ($callback)
905 $w = $loop->fork_ns ($callback)
906 Call the callback before the event loop is resumed in the child
907 process after a fork.
908
909 The "fork_ns" variant doesn't start (activate) the newly created
910 watcher.
911
912 EMBED WATCHERS - when one backend isn't enough...
913 This is a rather advanced watcher type that lets you embed one event
914 loop into another (currently only IO events are supported in the
915 embedded loop, other types of watchers might be handled in a delayed or
916 incorrect fashion and must not be used).
917
918 See the libev documentation at
919 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code
920 _when_one_backend_> (locally installed as EV::libev) for more details.
921
922 In short, this watcher is most useful on BSD systems without working
923 kqueue to still be able to handle a large number of sockets:
924
925 my $socket_loop;
926
927 # check wether we use SELECT or POLL _and_ KQUEUE is supported
928 if (
929 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
930 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
931 ) {
932 # use kqueue for sockets
933 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
934 }
935
936 # use the default loop otherwise
937 $socket_loop ||= EV::default_loop;
938
939 $w = EV::embed $otherloop[, $callback]
940 $w = EV::embed_ns $otherloop[, $callback]
941 $w = $loop->embed ($otherloop[, $callback])
942 $w = $loop->embed_ns ($otherloop[, $callback])
943 Call the callback when the embedded event loop ($otherloop) has any
944 I/O activity. The $callback is optional: if it is missing, then the
945 embedded event loop will be managed automatically (which is
946 recommended), otherwise you have to invoke "sweep" yourself.
947
948 The "embed_ns" variant doesn't start (activate) the newly created
949 watcher.
950
951 ASYNC WATCHERS - how to wake up another event loop
952 Async watchers are provided by EV, but have little use in perl directly,
953 as perl neither supports threads running in parallel nor direct access
954 to signal handlers or other contexts where they could be of value.
955
956 It is, however, possible to use them from the XS level.
957
958 Please see the libev documentation for further details.
959
960 $w = EV::async $callback
961 $w = EV::async_ns $callback
962 $w = $loop->async ($callback)
963 $w = $loop->async_ns ($callback)
964 $w->send
965 $bool = $w->async_pending
966
967 CLEANUP WATCHERS - how to clean up when the event loop goes away
968 Cleanup watchers are not supported on the Perl level, they can only be
969 used via XS currently.
970
971PERL SIGNALS
972 While Perl signal handling (%SIG) is not affected by EV, the behaviour
973 with EV is as the same as any other C library: Perl-signals will only be
974 handled when Perl runs, which means your signal handler might be invoked
975 only the next time an event callback is invoked.
976
977 The solution is to use EV signal watchers (see "EV::signal"), which will
978 ensure proper operations with regards to other event watchers.
979
980 If you cannot do this for whatever reason, you can also force a watcher
981 to be called on every event loop iteration by installing a "EV::check"
982 watcher:
983
984 my $async_check = EV::check sub { };
985
986 This ensures that perl gets into control for a short time to handle any
987 pending signals, and also ensures (slightly) slower overall operation.
988
511THREADS 989ITHREADS
512 Threads are not supported by this module in any way. Perl pseudo-threads 990 Ithreads are not supported by this module in any way. Perl
513 is evil stuff and must die. As soon as Perl gains real threads I will 991 pseudo-threads is evil stuff and must die. Real threads as provided by
514 work on thread support for it. 992 Coro are fully supported (and enhanced support is available via
993 Coro::EV).
515 994
516FORK 995FORK
517 Most of the "improved" event delivering mechanisms of modern operating 996 Most of the "improved" event delivering mechanisms of modern operating
518 systems have quite a few problems with fork(2) (to put it bluntly: it is 997 systems have quite a few problems with fork(2) (to put it bluntly: it is
519 not supported and usually destructive). Libev makes it possible to work 998 not supported and usually destructive). Libev makes it possible to work
… …
529 1008
530 On win32, there is no notion of fork so all this doesn't apply, of 1009 On win32, there is no notion of fork so all this doesn't apply, of
531 course. 1010 course.
532 1011
533SEE ALSO 1012SEE ALSO
534 L<EV::DNS>. 1013 EV::MakeMaker - MakeMaker interface to XS API, EV::ADNS (asynchronous
1014 DNS), Glib::EV (makes Glib/Gtk2 use EV as event loop), EV::Glib (embed
1015 Glib into EV), Coro::EV (efficient thread integration), Net::SNMP::EV
1016 (asynchronous SNMP), AnyEvent for event-loop agnostic and portable event
1017 driven programming.
535 1018
536AUTHOR 1019AUTHOR
537 Marc Lehmann <schmorp@schmorp.de> 1020 Marc Lehmann <schmorp@schmorp.de>
538 http://home.schmorp.de/ 1021 http://home.schmorp.de/
539 1022

Diff Legend

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