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Revision 1.47 by root, Tue Nov 19 20:11:01 2019 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
38
39 my $w = EV::child 666, sub {
40 my ($w, $revents) = @_;
41 my $status = $w->rstatus;
42 };
43
44 # STAT CHANGES 44 # STAT CHANGES
45 my $w = EV::stat "/etc/passwd", 10, sub { 45 my $w = EV::stat "/etc/passwd", 10, sub {
46 my ($w, $revents) = @_; 46 my ($w, $revents) = @_;
47 warn $w->path, " has changed somehow.\n"; 47 warn $w->path, " has changed somehow.\n";
48 }; 48 };
49 49
50 # MAINLOOP 50 # MAINLOOP
51 EV::loop; # loop until EV::unloop is called or all watchers stop 51 EV::run; # loop until EV::break is called or all watchers stop
52 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled 52 EV::run EV::RUN_ONCE; # block until at least one event could be handled
53 EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block 53 EV::run EV::RUN_NOWAIT; # try to handle same events, but do not block
54
55BEFORE YOU START USING THIS MODULE
56 If you only need timer, I/O, signal, child and idle watchers and not the
57 advanced functionality of this module, consider using AnyEvent instead,
58 specifically the simplified API described in AE.
59
60 When used with EV as backend, the AE API is as fast as the native EV
61 API, but your programs/modules will still run with many other event
62 loops.
54 63
55DESCRIPTION 64DESCRIPTION
56 This module provides an interface to libev 65 This module provides an interface to libev
57 (<http://software.schmorp.de/pkg/libev.html>). While the documentation 66 (<http://software.schmorp.de/pkg/libev.html>). While the documentation
58 below is comprehensive, one might also consult the documentation of 67 below is comprehensive, one might also consult the documentation of
59 libev itself (<http://cvs.schmorp.de/libev/ev.html>) for more subtle 68 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 69 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 70 discussion on the available backends, or how to force a specific backend
62 about in any case because it has much more detailed information. 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.
63 112
64EVENT LOOPS 113EVENT LOOPS
65 EV supports multiple event loops: There is a single "default event loop" 114 EV supports multiple event loops: There is a single "default event loop"
66 that can handle everything including signals and child watchers, and any 115 that can handle everything including signals and child watchers, and any
67 number of "dynamic event loops" that can use different backends (with 116 number of "dynamic event loops" that can use different backends (with
… …
72 selecting a working backend (which for example rules out kqueue on most 121 selecting a working backend (which for example rules out kqueue on most
73 BSDs). Modules should, unless they have "special needs" always use the 122 BSDs). Modules should, unless they have "special needs" always use the
74 default loop as this is fastest (perl-wise), best supported by other 123 default loop as this is fastest (perl-wise), best supported by other
75 modules (e.g. AnyEvent or Coro) and most portable event loop. 124 modules (e.g. AnyEvent or Coro) and most portable event loop.
76 125
77 For specific programs you cna create additional event loops dynamically. 126 For specific programs you can create additional event loops dynamically.
78 127
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
79 $loop = new EV::loop [$flags] 135 $loop = new EV::Loop [$flags]
80 Create a new event loop as per the specified flags. Please refer to 136 Create a new event loop as per the specified flags. Please refer to
81 the "ev_loop_new ()" function description in the libev documentation 137 the "ev_loop_new ()" function description in the libev documentation
82 (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI 138 (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI
83 ONS>) for more info. 139 ONS>, or locally-installed as EV::libev manpage) for more info.
84 140
85 The loop will automatically be destroyed when it is no longer 141 The loop will automatically be destroyed when it is no longer
86 referenced by any watcher and the loop object goes out of scope. 142 referenced by any watcher and the loop object goes out of scope.
87 143
88 Using "EV::FLAG_FORKCHECK" is recommended, as only the default event 144 If you are not embedding the loop, then Using "EV::FLAG_FORKCHECK"
89 loop is protected by this module. 145 is recommended, as only the default event loop is protected by this
146 module. If you *are* embedding this loop in the default loop, this
147 is not necessary, as "EV::embed" automatically does the right thing
148 on fork.
90 149
91 $loop->loop_fork 150 $loop->loop_fork
92 Must be called after a fork in the child, before entering or 151 Must be called after a fork in the child, before entering or
93 continuing the event loop. An alternative is to use 152 continuing the event loop. An alternative is to use
94 "EV::FLAG_FORKCHECK" which calls this fucntion automatically, at 153 "EV::FLAG_FORKCHECK" which calls this function automatically, at
95 some performance loss (refer to the libev documentation). 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.
96 167
97BASIC INTERFACE 168BASIC INTERFACE
98 $EV::DIED 169 $EV::DIED
99 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
100 callback throws an exception (with $@ containing the error). The 171 callback throws an exception (with $@ containing the error). The
101 default prints an informative message and continues. 172 default prints an informative message and continues.
102 173
103 If this callback throws an exception it will be silently ignored. 174 If this callback throws an exception it will be silently ignored.
104 175
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.
186
105 $time = EV::time 187 $time = EV::time
106 Returns the current time in (fractional) seconds since the epoch. 188 Returns the current time in (fractional) seconds since the epoch.
107 189
108 $time = EV::now 190 $time = EV::now
109 $time = $loop->now 191 $time = $loop->now
110 Returns the time the last event loop iteration has been started. 192 Returns the time the last event loop iteration has been started.
111 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
112 to it is usually faster then calling EV::time. 194 to it is usually faster then calling EV::time.
195
196 EV::now_update
197 $loop->now_update
198 Establishes the current time by querying the kernel, updating the
199 time returned by "EV::now" in the progress. This is a costly
200 operation and is usually done automatically within "EV::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").
113 232
114 $backend = EV::backend 233 $backend = EV::backend
115 $backend = $loop->backend 234 $backend = $loop->backend
116 Returns an integer describing the backend used by libev 235 Returns an integer describing the backend used by libev
117 (EV::METHOD_SELECT or EV::METHOD_EPOLL). 236 (EV::BACKEND_SELECT or EV::BACKEND_EPOLL).
118 237
119 EV::loop [$flags] 238 $active = EV::run [$flags]
120 $loop->loop ([$flags]) 239 $active = $loop->run ([$flags])
121 Begin checking for events and calling callbacks. It returns when a 240 Begin checking for events and calling callbacks. It returns when a
122 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".
123 246
124 The $flags argument can be one of the following: 247 The $flags argument can be one of the following:
125 248
126 0 as above 249 0 as above
127 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 250 EV::RUN_ONCE block at most once (wait, but do not loop)
128 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 251 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
129 252
130 EV::unloop [$how] 253 EV::break [$how]
131 $loop->unloop ([$how]) 254 $loop->break ([$how])
132 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
133 makes the innermost call to EV::loop return. 256 the innermost call to EV::run return.
134 257
135 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
136 EV::loop will return as fast as possible. 259 will return as fast as possible.
137 260
138 $count = EV::loop_count 261 When called with an argument of EV::BREAK_CANCEL, any pending break
139 $count = $loop->loop_count 262 will be cancelled.
263
264 $count = EV::iteration
265 $count = $loop->iteration
140 Return the number of times the event loop has polled for new events. 266 Return the number of times the event loop has polled for new events.
141 Sometiems useful as a generation counter. 267 Sometimes useful as a generation counter.
142 268
143 EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 269 EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
144 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 270 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
145 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
146 one-shot event without the need for managing a watcher object. 272 one-shot event without the need for managing a watcher object.
… …
150 "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
151 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
152 "undef" for $fh_or_undef and 0 for $events). 278 "undef" for $fh_or_undef and 0 for $events).
153 279
154 If timeout is "undef" or negative, then there will be no timeout. 280 If timeout is "undef" or negative, then there will be no timeout.
155 Otherwise a EV::timer with this value will be started. 281 Otherwise an "EV::timer" with this value will be started.
156 282
157 When an error occurs or either the timeout or I/O watcher triggers, 283 When an error occurs or either the timeout or I/O watcher triggers,
158 then the callback will be called with the received event set (in 284 then the callback will be called with the received event set (in
159 general you can expect it to be a combination of "EV::ERROR", 285 general you can expect it to be a combination of "EV::ERROR",
160 "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). 286 "EV::READ", "EV::WRITE" and "EV::TIMER").
161 287
162 EV::once doesn't return anything: the watchers stay active till 288 EV::once doesn't return anything: the watchers stay active till
163 either of them triggers, then they will be stopped and freed, and 289 either of them triggers, then they will be stopped and freed, and
164 the callback invoked. 290 the callback invoked.
165 291
166 EV::feed_fd_event ($fd, $revents) 292 EV::feed_fd_event $fd, $revents
167 $loop->feed_fd_event ($fd, $revents) 293 $loop->feed_fd_event ($fd, $revents)
168 Feed an event on a file descriptor into EV. EV will react to this 294 Feed an event on a file descriptor into EV. EV will react to this
169 call as if the readyness notifications specified by $revents (a 295 call as if the readyness notifications specified by $revents (a
170 combination of "EV::READ" and "EV::WRITE") happened on the file 296 combination of "EV::READ" and "EV::WRITE") happened on the file
171 descriptor $fd. 297 descriptor $fd.
172 298
173 EV::feed_signal_event ($signal) 299 EV::feed_signal_event $signal
174 Feed a signal event into EV. EV will react to this call as if the 300 Feed a signal event into the default loop. EV will react to this
175 signal specified by $signal had occured. 301 call as if the signal specified by $signal had occured.
302
303 EV::feed_signal $signal
304 Feed a signal event into EV - unlike "EV::feed_signal_event", this
305 works regardless of which loop has registered the signal, and is
306 mainly useful 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.
176 326
177WATCHER OBJECTS 327WATCHER OBJECTS
178 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
179 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,
180 you would create an EV::io watcher for that: 330 you would create an EV::io watcher for that:
181 331
182 my $watcher = EV::io *STDIN, EV::READ, sub { 332 my $watcher = EV::io *STDIN, EV::READ, sub {
183 my ($watcher, $revents) = @_; 333 my ($watcher, $revents) = @_;
184 warn "yeah, STDIN should now be readable without blocking!\n" 334 warn "yeah, STDIN should now be readable without blocking!\n"
185 }; 335 };
186 336
187 All watchers can be active (waiting for events) or inactive (paused). 337 All watchers can be active (waiting for events) or inactive (paused).
188 Only active watchers will have their callbacks invoked. All callbacks 338 Only active watchers will have their callbacks invoked. All callbacks
189 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
190 received events. 340 received events.
191 341
192 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
193 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
194 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,
195 EV::periodic sets EV::PERIODIC and so on, with the exception of I/O 345 EV::periodic sets EV::PERIODIC and so on, with the exception of I/O
196 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).
197 (which uses EV::TIMEOUT).
198 347
199 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
200 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
201 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.
202 351
… …
265 If the watcher is pending, this function clears its pending status 414 If the watcher is pending, this function clears its pending status
266 and returns its $revents bitset (as if its callback was invoked). If 415 and returns its $revents bitset (as if its callback was invoked). If
267 the watcher isn't pending it does nothing and returns 0. 416 the watcher isn't pending it does nothing and returns 0.
268 417
269 $previous_state = $w->keepalive ($bool) 418 $previous_state = $w->keepalive ($bool)
270 Normally, "EV::loop" will return when there are no active watchers 419 Normally, "EV::run" will return when there are no active watchers
271 (which is a "deadlock" because no progress can be made anymore). 420 (which is a "deadlock" because no progress can be made anymore).
272 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
273 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
274 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
275 for their task :). 424 for their task :).
276 425
277 Sometimes, however, this gets in your way, for example when the 426 Sometimes, however, this gets in your way, for example when the
278 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
279 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
280 module written by somebody else even). Then you might want any 429 module written by somebody else even). Then you might want any
281 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
282 "EV::loop" from returning just because you happen to have this 431 "EV::run" from returning just because you happen to have this
283 long-running UDP port watcher. 432 long-running UDP port watcher.
284 433
285 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
286 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
287 returning. 436 returning.
288 437
289 The initial value for keepalive is true (enabled), and you cna 438 The initial value for keepalive is true (enabled), and you can
290 change it any time. 439 change it any time.
291 440
292 Example: Register an I/O watcher for some UDP socket but do not keep 441 Example: Register an I/O watcher for some UDP socket but do not keep
293 the event loop from running just because of that watcher. 442 the event loop from running just because of that watcher.
294 443
295 my $udp_socket = ... 444 my $udp_socket = ...
296 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 445 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
297 $1000udp_watcher->keepalive (0); 446 $udp_watcher->keepalive (0);
298 447
299 $loop = $w->loop 448 $loop = $w->loop
300 Return the loop that this watcher is attached to. 449 Return the loop that this watcher is attached to.
301 450
302WATCHER TYPES 451WATCHER TYPES
… …
333 TIMER WATCHERS - relative and optionally repeating timeouts 482 TIMER WATCHERS - relative and optionally repeating timeouts
334 $w = EV::timer $after, $repeat, $callback 483 $w = EV::timer $after, $repeat, $callback
335 $w = EV::timer_ns $after, $repeat, $callback 484 $w = EV::timer_ns $after, $repeat, $callback
336 $w = $loop->timer ($after, $repeat, $callback) 485 $w = $loop->timer ($after, $repeat, $callback)
337 $w = $loop->timer_ns ($after, $repeat, $callback) 486 $w = $loop->timer_ns ($after, $repeat, $callback)
338 Calls the callback after $after seconds (which may be fractional). 487 Calls the callback after $after seconds (which may be fractional or
339 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
340 $repeat value as $after) after the callback returns. 489 the $repeat value as $after) after the callback returns.
341 490
342 This means that the callback would be called roughly after $after 491 This means that the callback would be called roughly after $after
343 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
344 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
345 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
… …
352 the same time. 501 the same time.
353 502
354 The "timer_ns" variant doesn't start (activate) the newly created 503 The "timer_ns" variant doesn't start (activate) the newly created
355 watcher. 504 watcher.
356 505
357 $w->set ($after, $repeat) 506 $w->set ($after, $repeat = 0)
358 Reconfigures the watcher, see the constructor above for details. Can 507 Reconfigures the watcher, see the constructor above for details. Can
359 be called at any time. 508 be called at any time.
360 509
361 $w->again 510 $w->again
511 $w->again ($repeat)
362 Similar to the "start" method, but has special semantics for 512 Similar to the "start" method, but has special semantics for
363 repeating timers: 513 repeating timers:
364 514
365 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.
366 516
… …
374 524
375 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
376 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
377 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"
378 method on the timeout. 528 method on the timeout.
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.
379 535
380 PERIODIC WATCHERS - to cron or not to cron? 536 PERIODIC WATCHERS - to cron or not to cron?
381 $w = EV::periodic $at, $interval, $reschedule_cb, $callback 537 $w = EV::periodic $at, $interval, $reschedule_cb, $callback
382 $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 538 $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
383 $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback) 539 $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
… …
390 changed by explicit date -s or other means such as ntpd). It is also 546 changed by explicit date -s or other means such as ntpd). It is also
391 the most complex watcher type in EV. 547 the most complex watcher type in EV.
392 548
393 It has three distinct "modes": 549 It has three distinct "modes":
394 550
395 * absolute timer ($interval = $reschedule_cb = 0) 551 * absolute timer ($interval = $reschedule_cb = 0)
552
396 This time simply fires at the wallclock time $at and doesn't 553 This time simply fires at the wallclock time $at and doesn't
397 repeat. It will not adjust when a time jump occurs, that is, if 554 repeat. It will not adjust when a time jump occurs, that is, if
398 it is to be run at January 1st 2011 then it will run when the 555 it is to be run at January 1st 2011 then it will run when the
399 system time reaches or surpasses this time. 556 system time reaches or surpasses this time.
400 557
401 * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) 558 * repeating interval timer ($interval > 0, $reschedule_cb = 0)
559
402 In this mode the watcher will always be scheduled to time out at 560 In this mode the watcher will always be scheduled to time out at
403 the next "$at + N * $interval" time (for some integer N) and 561 the next "$at + N * $interval" time (for the lowest integer N)
404 then repeat, regardless of any time jumps. 562 and then repeat, regardless of any time jumps. Note that, since
563 "N" can be negative, the first trigger can happen before $at.
405 564
406 This can be used to create timers that do not drift with respect 565 This can be used to create timers that do not drift with respect
407 to system time: 566 to system time:
408 567
409 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; 568 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
410 569
411 That doesn't mean there will always be 3600 seconds in between 570 That doesn't mean there will always be 3600 seconds in between
412 triggers, but only that the the clalback will be called when the 571 triggers, but only that the the callback will be called when the
413 system time shows a full hour (UTC). 572 system time shows a full hour (UTC).
414 573
415 Another way to think about it (for the mathematically inclined) 574 Another way to think about it (for the mathematically inclined)
416 is that EV::periodic will try to run the callback in this mode 575 is that EV::periodic will try to run the callback in this mode
417 at the next possible time where "$time = $at (mod $interval)", 576 at the next possible time where "$time = $at (mod $interval)",
418 regardless of any time jumps. 577 regardless of any time jumps.
419 578
420 * manual reschedule mode ($reschedule_cb = coderef) 579 * manual reschedule mode ($reschedule_cb = coderef)
580
421 In this mode $interval and $at are both being ignored. Instead, 581 In this mode $interval and $at are both being ignored. Instead,
422 each time the periodic watcher gets scheduled, the reschedule 582 each time the periodic watcher gets scheduled, the reschedule
423 callback ($reschedule_cb) will be called with the watcher as 583 callback ($reschedule_cb) will be called with the watcher as
424 first, and the current time as second argument. 584 first, and the current time as second argument.
425 585
426 *This callback MUST NOT stop or destroy this or any other 586 *This callback MUST NOT stop or destroy this or any other
587 periodic watcher, ever, and MUST NOT call any event loop
427 periodic watcher, ever*. If you need to stop it, return 1e30 and 588 functions or methods*. If you need to stop it, return 1e30 and
428 stop it afterwards. 589 stop it afterwards. You may create and start an "EV::prepare"
590 watcher for this task.
429 591
430 It must return the next time to trigger, based on the passed 592 It must return the next time to trigger, based on the passed
431 time value (that is, the lowest time value larger than to the 593 time value (that is, the lowest time value larger than or equal
432 second argument). It will usually be called just before the 594 to to the second argument). It will usually be called just
433 callback will be triggered, but might be called at other times, 595 before the callback will be triggered, but might be called at
434 too. 596 other times, too.
435 597
436 This can be used to create very complex timers, such as a timer 598 This can be used to create very complex timers, such as a timer
437 that triggers on each midnight, local time (actually 24 hours 599 that triggers on each midnight, local time (actually one day
438 after the last midnight, to keep the example simple. If you know 600 after the last midnight, to keep the example simple):
439 a way to do it correctly in about the same space (without
440 requiring elaborate modules), drop me a note :):
441 601
442 my $daily = EV::periodic 0, 0, sub { 602 my $daily = EV::periodic 0, 0, sub {
443 my ($w, $now) = @_; 603 my ($w, $now) = @_;
444 604
445 use Time::Local (); 605 use Time::Local ();
446 my (undef, undef, undef, $d, $m, $y) = localtime $now; 606 my (undef, undef, undef, $d, $m, $y) = localtime $now;
447 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y 607 Time::Local::timelocal_nocheck 0, 0, 0, $d + 1, $m, $y
448 }, sub { 608 }, sub {
449 print "it's midnight or likely shortly after, now\n"; 609 print "it's midnight or likely shortly after, now\n";
450 }; 610 };
451 611
452 The "periodic_ns" variant doesn't start (activate) the newly created 612 The "periodic_ns" variant doesn't start (activate) the newly created
… …
463 Return the time that the watcher is expected to trigger next. 623 Return the time that the watcher is expected to trigger next.
464 624
465 SIGNAL WATCHERS - signal me when a signal gets signalled! 625 SIGNAL WATCHERS - signal me when a signal gets signalled!
466 $w = EV::signal $signal, $callback 626 $w = EV::signal $signal, $callback
467 $w = EV::signal_ns $signal, $callback 627 $w = EV::signal_ns $signal, $callback
628 $w = $loop->signal ($signal, $callback)
629 $w = $loop->signal_ns ($signal, $callback)
468 Call the callback when $signal is received (the signal can be 630 Call the callback when $signal is received (the signal can be
469 specified by number or by name, just as with "kill" or %SIG). 631 specified by number or by name, just as with "kill" or %SIG).
632
633 Only one event loop can grab a given signal - attempting to grab the
634 same signal from two EV loops will crash the program immediately or
635 cause data corruption.
470 636
471 EV will grab the signal for the process (the kernel only allows one 637 EV will grab the signal for the process (the kernel only allows one
472 component to receive a signal at a time) when you start a signal 638 component to receive a signal at a time) when you start a signal
473 watcher, and removes it again when you stop it. Perl does the same 639 watcher, and removes it again when you stop it. Perl does the same
474 when you add/remove callbacks to %SIG, so watch out. 640 when you add/remove callbacks to %SIG, so watch out.
… …
486 $old_signum = $w->signal ($new_signal) 652 $old_signum = $w->signal ($new_signal)
487 Returns the previously set signal (always as a number not name) and 653 Returns the previously set signal (always as a number not name) and
488 optionally set a new one. 654 optionally set a new one.
489 655
490 CHILD WATCHERS - watch out for process status changes 656 CHILD WATCHERS - watch out for process status changes
491 $w = EV::child $pid, $callback 657 $w = EV::child $pid, $trace, $callback
492 $w = EV::child_ns $pid, $callback 658 $w = EV::child_ns $pid, $trace, $callback
493 $w = $loop->child ($pid, $callback) 659 $w = $loop->child ($pid, $trace, $callback)
494 $w = $loop->child_ns ($pid, $callback) 660 $w = $loop->child_ns ($pid, $trace, $callback)
495 Call the callback when a status change for pid $pid (or any pid if 661 Call the callback when a status change for pid $pid (or any pid if
496 $pid is 0) has been received. More precisely: when the process 662 $pid is 0) has been received (a status change happens when the
663 process terminates or is killed, or, when trace is true,
664 additionally when it is stopped or continued). More precisely: when
497 receives a "SIGCHLD", EV will fetch the outstanding exit/wait status 665 the process receives a "SIGCHLD", EV will fetch the outstanding
498 for all changed/zombie children and call the callback. 666 exit/wait status for all changed/zombie children and call the
667 callback.
499 668
500 It is valid (and fully supported) to install a child watcher after a 669 It is valid (and fully supported) to install a child watcher after a
501 child has exited but before the event loop has started its next 670 child has exited but before the event loop has started its next
502 iteration (for example, first you "fork", then the new child process 671 iteration (for example, first you "fork", then the new child process
503 might exit, and only then do you install a child watcher in the 672 might exit, and only then do you install a child watcher in the
… …
510 be called. 679 be called.
511 680
512 The "child_ns" variant doesn't start (activate) the newly created 681 The "child_ns" variant doesn't start (activate) the newly created
513 watcher. 682 watcher.
514 683
515 $w->set ($pid) 684 $w->set ($pid, $trace)
516 Reconfigures the watcher, see the constructor above for details. Can 685 Reconfigures the watcher, see the constructor above for details. Can
517 be called at any time. 686 be called at any time.
518 687
519 $current_pid = $w->pid 688 $current_pid = $w->pid
520 $old_pid = $w->pid ($new_pid)
521 Returns the previously set process id and optionally set a new one. 689 Returns the previously set process id and optionally set a new one.
522 690
523 $exit_status = $w->rstatus 691 $exit_status = $w->rstatus
524 Return the exit/wait status (as returned by waitpid, see the waitpid 692 Return the exit/wait status (as returned by waitpid, see the waitpid
525 entry in perlfunc). 693 entry in perlfunc).
… …
646 $w = $loop->check_ns ($callback) 814 $w = $loop->check_ns ($callback)
647 Call the callback just after the process wakes up again (after it 815 Call the callback just after the process wakes up again (after it
648 has gathered events), but before any other callbacks have been 816 has gathered events), but before any other callbacks have been
649 invoked. 817 invoked.
650 818
651 This is used to integrate other event-based software into the EV 819 This can be used to integrate other event-based software into the EV
652 mainloop: You register a prepare callback and in there, you create 820 mainloop: You register a prepare callback and in there, you create
653 io and timer watchers as required by the other software. Here is a 821 io and timer watchers as required by the other software. Here is a
654 real-world example of integrating Net::SNMP (with some details left 822 real-world example of integrating Net::SNMP (with some details left
655 out): 823 out):
656 824
… …
687 # make the dispatcher handle any new stuff 855 # make the dispatcher handle any new stuff
688 ... not shown 856 ... not shown
689 }; 857 };
690 858
691 The callbacks of the created watchers will not be called as the 859 The callbacks of the created watchers will not be called as the
692 watchers are destroyed before this cna happen (remember EV::check 860 watchers are destroyed before this can happen (remember EV::check
693 gets called first). 861 gets called first).
694 862
695 The "check_ns" variant doesn't start (activate) the newly created 863 The "check_ns" variant doesn't start (activate) the newly created
696 watcher. 864 watcher.
865
866 EV::CHECK constant issues
867 Like all other watcher types, there is a bitmask constant for use in
868 $revents and other places. The "EV::CHECK" is special as it has the
869 same name as the "CHECK" sub called by Perl. This doesn't cause big
870 issues on newer perls (beginning with 5.8.9), but it means thatthe
871 constant must be *inlined*, i.e. runtime calls will not work. That
872 means that as long as you always "use EV" and then "EV::CHECK" you
873 are on the safe side.
697 874
698 FORK WATCHERS - the audacity to resume the event loop after a fork 875 FORK WATCHERS - the audacity to resume the event loop after a fork
699 Fork watchers are called when a "fork ()" was detected. The invocation 876 Fork watchers are called when a "fork ()" was detected. The invocation
700 is done before the event loop blocks next and before "check" watchers 877 is done before the event loop blocks next and before "check" watchers
701 are being called, and only in the child after the fork. 878 are being called, and only in the child after the fork.
… …
708 process after a fork. 885 process after a fork.
709 886
710 The "fork_ns" variant doesn't start (activate) the newly created 887 The "fork_ns" variant doesn't start (activate) the newly created
711 watcher. 888 watcher.
712 889
890 EMBED WATCHERS - when one backend isn't enough...
891 This is a rather advanced watcher type that lets you embed one event
892 loop into another (currently only IO events are supported in the
893 embedded loop, other types of watchers might be handled in a delayed or
894 incorrect fashion and must not be used).
895
896 See the libev documentation at
897 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code
898 _when_one_backend_> (locally installed as EV::libev) for more details.
899
900 In short, this watcher is most useful on BSD systems without working
901 kqueue to still be able to handle a large number of sockets:
902
903 my $socket_loop;
904
905 # check wether we use SELECT or POLL _and_ KQUEUE is supported
906 if (
907 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
908 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
909 ) {
910 # use kqueue for sockets
911 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
912 }
913
914 # use the default loop otherwise
915 $socket_loop ||= EV::default_loop;
916
917 $w = EV::embed $otherloop[, $callback]
918 $w = EV::embed_ns $otherloop[, $callback]
919 $w = $loop->embed ($otherloop[, $callback])
920 $w = $loop->embed_ns ($otherloop[, $callback])
921 Call the callback when the embedded event loop ($otherloop) has any
922 I/O activity. The $callback is optional: if it is missing, then the
923 embedded event loop will be managed automatically (which is
924 recommended), otherwise you have to invoke "sweep" yourself.
925
926 The "embed_ns" variant doesn't start (activate) the newly created
927 watcher.
928
929 ASYNC WATCHERS - how to wake up another event loop
930 Async watchers are provided by EV, but have little use in perl directly,
931 as perl neither supports threads running in parallel nor direct access
932 to signal handlers or other contexts where they could be of value.
933
934 It is, however, possible to use them from the XS level.
935
936 Please see the libev documentation for further details.
937
938 $w = EV::async $callback
939 $w = EV::async_ns $callback
940 $w = $loop->async ($callback)
941 $w = $loop->async_ns ($callback)
942 $w->send
943 $bool = $w->async_pending
944
945 CLEANUP WATCHERS - how to clean up when the event loop goes away
946 Cleanup watchers are not supported on the Perl level, they can only be
947 used via XS currently.
948
713PERL SIGNALS 949PERL SIGNALS
714 While Perl signal handling (%SIG) is not affected by EV, the behaviour 950 While Perl signal handling (%SIG) is not affected by EV, the behaviour
715 with EV is as the same as any other C library: Perl-signals will only be 951 with EV is as the same as any other C library: Perl-signals will only be
716 handled when Perl runs, which means your signal handler might be invoked 952 handled when Perl runs, which means your signal handler might be invoked
717 only the next time an event callback is invoked. 953 only the next time an event callback is invoked.
… …
726 my $async_check = EV::check sub { }; 962 my $async_check = EV::check sub { };
727 963
728 This ensures that perl gets into control for a short time to handle any 964 This ensures that perl gets into control for a short time to handle any
729 pending signals, and also ensures (slightly) slower overall operation. 965 pending signals, and also ensures (slightly) slower overall operation.
730 966
731THREADS 967ITHREADS
732 Threads are not supported by this module in any way. Perl pseudo-threads 968 Ithreads are not supported by this module in any way. Perl
733 is evil stuff and must die. As soon as Perl gains real threads I will 969 pseudo-threads is evil stuff and must die. Real threads as provided by
734 work on thread support for it. 970 Coro are fully supported (and enhanced support is available via
971 Coro::EV).
735 972
736FORK 973FORK
737 Most of the "improved" event delivering mechanisms of modern operating 974 Most of the "improved" event delivering mechanisms of modern operating
738 systems have quite a few problems with fork(2) (to put it bluntly: it is 975 systems have quite a few problems with fork(2) (to put it bluntly: it is
739 not supported and usually destructive). Libev makes it possible to work 976 not supported and usually destructive). Libev makes it possible to work
… …
749 986
750 On win32, there is no notion of fork so all this doesn't apply, of 987 On win32, there is no notion of fork so all this doesn't apply, of
751 course. 988 course.
752 989
753SEE ALSO 990SEE ALSO
754 EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event 991 EV::MakeMaker - MakeMaker interface to XS API, EV::ADNS (asynchronous
755 loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines 992 DNS), Glib::EV (makes Glib/Gtk2 use EV as event loop), EV::Glib (embed
756 with EV), Net::SNMP::EV (asynchronous SNMP). 993 Glib into EV), Coro::EV (efficient thread integration), Net::SNMP::EV
994 (asynchronous SNMP), AnyEvent for event-loop agnostic and portable event
995 driven programming.
757 996
758AUTHOR 997AUTHOR
759 Marc Lehmann <schmorp@schmorp.de> 998 Marc Lehmann <schmorp@schmorp.de>
760 http://home.schmorp.de/ 999 http://home.schmorp.de/
761 1000

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