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

Comparing EV/README (file contents):
Revision 1.27 by root, Mon May 26 05:37:18 2008 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 7
8 # TIMERS 8 # TIMERS
9 9
10 my $w = EV::timer 2, 0, sub { 10 my $w = EV::timer 2, 0, sub {
11 warn "is called after 2s"; 11 warn "is called after 2s";
12 }; 12 };
13 13
14 my $w = EV::timer 2, 2, sub { 14 my $w = EV::timer 2, 2, sub {
15 warn "is called roughly every 2s (repeat = 2)"; 15 warn "is called roughly every 2s (repeat = 2)";
16 }; 16 };
17 17
18 undef $w; # destroy event watcher again 18 undef $w; # destroy event watcher again
19 19
20 my $w = EV::periodic 0, 60, 0, sub { 20 my $w = EV::periodic 0, 60, 0, sub {
21 warn "is called every minute, on the minute, exactly"; 21 warn "is called every minute, on the minute, exactly";
22 }; 22 };
23 23
24 # IO 24 # IO
25 25
26 my $w = EV::io *STDIN, EV::READ, sub { 26 my $w = EV::io *STDIN, EV::READ, sub {
27 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask 27 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
28 warn "stdin is readable, you entered: ", <STDIN>; 28 warn "stdin is readable, you entered: ", <STDIN>;
29 }; 29 };
30 30
31 # SIGNALS 31 # SIGNALS
32 32
33 my $w = EV::signal 'QUIT', sub { 33 my $w = EV::signal 'QUIT', sub {
34 warn "sigquit received\n"; 34 warn "sigquit received\n";
35 }; 35 };
36 36
37 # CHILD/PID STATUS CHANGES 37 # CHILD/PID STATUS CHANGES
38 38
39 my $w = EV::child 666, 0, sub { 39 my $w = EV::child 666, 0, sub {
40 my ($w, $revents) = @_; 40 my ($w, $revents) = @_;
41 my $status = $w->rstatus; 41 my $status = $w->rstatus;
42 }; 42 };
43 43
44 # STAT CHANGES 44 # STAT CHANGES
45 my $w = EV::stat "/etc/passwd", 10, sub { 45 my $w = EV::stat "/etc/passwd", 10, sub {
46 my ($w, $revents) = @_; 46 my ($w, $revents) = @_;
47 warn $w->path, " has changed somehow.\n"; 47 warn $w->path, " has changed somehow.\n";
48 }; 48 };
49 49
50 # MAINLOOP 50 # MAINLOOP
51 EV::loop; # loop until EV::unloop is called or all watchers stop 51 EV::run; # loop until EV::break is called or all watchers stop
52 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled 52 EV::run EV::RUN_ONCE; # block until at least one event could be handled
53 EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block 53 EV::run EV::RUN_NOWAIT; # try to handle same events, but do not block
54
55BEFORE YOU START USING THIS MODULE
56 If you only need timer, I/O, signal, child and idle watchers and not the
57 advanced functionality of this module, consider using AnyEvent instead,
58 specifically the simplified API described in AE.
59
60 When used with EV as backend, the AE API is as fast as the native EV
61 API, but your programs/modules will still run with many other event
62 loops.
54 63
55DESCRIPTION 64DESCRIPTION
56 This module provides an interface to libev 65 This module provides an interface to libev
57 (<http://software.schmorp.de/pkg/libev.html>). While the documentation 66 (<http://software.schmorp.de/pkg/libev.html>). While the documentation
58 below is comprehensive, one might also consult the documentation of 67 below is comprehensive, one might also consult the documentation of
59 libev itself (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>) 68 libev itself (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
60 for more subtle details on watcher semantics or some discussion on the 69 perldoc EV::libev) for more subtle details on watcher semantics or some
61 available backends, or how to force a specific backend with 70 discussion on the available backends, or how to force a specific backend
62 "LIBEV_FLAGS", or just about in any case because it has much more 71 with "LIBEV_FLAGS", or just about in any case because it has much more
63 detailed information. 72 detailed information.
64 73
65 This module is very fast and scalable. It is actually so fast that you 74 This module is very fast and scalable. It is actually so fast that you
66 can use it through the AnyEvent module, stay portable to other event 75 can use it through the AnyEvent module, stay portable to other event
67 loops (if you don't rely on any watcher types not available through it) 76 loops (if you don't rely on any watcher types not available through it)
68 and still be faster than with any other event loop currently supported 77 and still be faster than with any other event loop currently supported
69 in Perl. 78 in Perl.
79
80 PORTING FROM EV 3.X to 4.X
81 EV version 4 introduces a number of incompatible changes summarised
82 here. According to the depreciation strategy used by libev, there is a
83 compatibility layer in place so programs should continue to run
84 unchanged (the XS interface lacks this layer, so programs using that one
85 need to be updated).
86
87 This compatibility layer will be switched off in some future release.
88
89 All changes relevant to Perl are renames of symbols, functions and
90 methods:
91
92 EV::loop => EV::run
93 EV::LOOP_NONBLOCK => EV::RUN_NOWAIT
94 EV::LOOP_ONESHOT => EV::RUN_ONCE
95
96 EV::unloop => EV::break
97 EV::UNLOOP_CANCEL => EV::BREAK_CANCEL
98 EV::UNLOOP_ONE => EV::BREAK_ONE
99 EV::UNLOOP_ALL => EV::BREAK_ALL
100
101 EV::TIMEOUT => EV::TIMER
102
103 EV::loop_count => EV::iteration
104 EV::loop_depth => EV::depth
105 EV::loop_verify => EV::verify
106
107 The loop object methods corresponding to the functions above have been
108 similarly renamed.
109
110 MODULE EXPORTS
111 This module does not export any symbols.
70 112
71EVENT LOOPS 113EVENT LOOPS
72 EV supports multiple event loops: There is a single "default event loop" 114 EV supports multiple event loops: There is a single "default event loop"
73 that can handle everything including signals and child watchers, and any 115 that can handle everything including signals and child watchers, and any
74 number of "dynamic event loops" that can use different backends (with 116 number of "dynamic event loops" that can use different backends (with
… …
81 default loop as this is fastest (perl-wise), best supported by other 123 default loop as this is fastest (perl-wise), best supported by other
82 modules (e.g. AnyEvent or Coro) and most portable event loop. 124 modules (e.g. AnyEvent or Coro) and most portable event loop.
83 125
84 For specific programs you can create additional event loops dynamically. 126 For specific programs you can create additional event loops dynamically.
85 127
128 If you want to take advantage of kqueue (which often works properly for
129 sockets only) even though the default loop doesn't enable it, you can
130 *embed* a kqueue loop into the default loop: running the default loop
131 will then also service the kqueue loop to some extent. See the example
132 in the section about embed watchers for an example on how to achieve
133 that.
134
86 $loop = new EV::loop [$flags] 135 $loop = new EV::Loop [$flags]
87 Create a new event loop as per the specified flags. Please refer to 136 Create a new event loop as per the specified flags. Please refer to
88 the "ev_loop_new ()" function description in the libev documentation 137 the "ev_loop_new ()" function description in the libev documentation
89 (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI 138 (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI
90 ONS>) for more info. 139 ONS>, or locally-installed as EV::libev manpage) for more info.
91 140
92 The loop will automatically be destroyed when it is no longer 141 The loop will automatically be destroyed when it is no longer
93 referenced by any watcher and the loop object goes out of scope. 142 referenced by any watcher and the loop object goes out of scope.
94 143
95 Using "EV::FLAG_FORKCHECK" is recommended, as only the default event 144 If you are not embedding the loop, then Using "EV::FLAG_FORKCHECK"
96 loop is protected by this module. 145 is recommended, as only the default event loop is protected by this
146 module. If you *are* embedding this loop in the default loop, this
147 is not necessary, as "EV::embed" automatically does the right thing
148 on fork.
97 149
98 $loop->loop_fork 150 $loop->loop_fork
99 Must be called after a fork in the child, before entering or 151 Must be called after a fork in the child, before entering or
100 continuing the event loop. An alternative is to use 152 continuing the event loop. An alternative is to use
101 "EV::FLAG_FORKCHECK" which calls this function automatically, at 153 "EV::FLAG_FORKCHECK" which calls this function automatically, at
102 some performance loss (refer to the libev documentation). 154 some performance loss (refer to the libev documentation).
103 155
104 $loop->loop_verify 156 $loop->verify
105 Calls "ev_verify" to make internal consistency checks (for debugging 157 Calls "ev_verify" to make internal consistency checks (for debugging
106 libev) and abort the program if any data structures wree found to be 158 libev) and abort the program if any data structures were found to be
107 corrupted. 159 corrupted.
108 160
109 $loop = EV::default_loop [$flags] 161 $loop = EV::default_loop [$flags]
110 Return the default loop (which is a singleton object). Since this 162 Return the default loop (which is a singleton object). Since this
111 module already creates the default loop with default flags, 163 module already creates the default loop with default flags,
112 specifying flags here will not have any effect unless you destroy 164 specifying flags here will not have any effect unless you destroy
113 the default loop. 165 the default loop first, which isn't supported. So in short: don't do
166 it, and if you break it, you get to keep the pieces.
114 167
115BASIC INTERFACE 168BASIC INTERFACE
116 $EV::DIED 169 $EV::DIED
117 Must contain a reference to a function that is called when a 170 Must contain a reference to a function that is called when a
118 callback throws an exception (with $@ containing the error). The 171 callback throws an exception (with $@ containing the error). The
… …
135 Returns the current time in (fractional) seconds since the epoch. 188 Returns the current time in (fractional) seconds since the epoch.
136 189
137 $time = EV::now 190 $time = EV::now
138 $time = $loop->now 191 $time = $loop->now
139 Returns the time the last event loop iteration has been started. 192 Returns the time the last event loop iteration has been started.
140 This is the time that (relative) timers are based on, and refering 193 This is the time that (relative) timers are based on, and referring
141 to it is usually faster then calling EV::time. 194 to it is usually faster then calling EV::time.
195
196 EV::now_update
197 $loop->now_update
198 Establishes the current time by querying the kernel, updating the
199 time returned by "EV::now" in the progress. This is a costly
200 operation and is usually done automatically within "EV::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").
142 232
143 $backend = EV::backend 233 $backend = EV::backend
144 $backend = $loop->backend 234 $backend = $loop->backend
145 Returns an integer describing the backend used by libev 235 Returns an integer describing the backend used by libev
146 (EV::METHOD_SELECT or EV::METHOD_EPOLL). 236 (EV::BACKEND_SELECT or EV::BACKEND_EPOLL).
147 237
148 EV::loop [$flags] 238 $active = EV::run [$flags]
149 $loop->loop ([$flags]) 239 $active = $loop->run ([$flags])
150 Begin checking for events and calling callbacks. It returns when a 240 Begin checking for events and calling callbacks. It returns when a
151 callback calls EV::unloop. 241 callback calls EV::break or the 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".
152 246
153 The $flags argument can be one of the following: 247 The $flags argument can be one of the following:
154 248
155 0 as above 249 0 as above
156 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 250 EV::RUN_ONCE block at most once (wait, but do not loop)
157 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 251 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
158 252
159 EV::unloop [$how] 253 EV::break [$how]
160 $loop->unloop ([$how]) 254 $loop->break ([$how])
161 When called with no arguments or an argument of EV::UNLOOP_ONE, 255 When called with no arguments or an argument of EV::BREAK_ONE, makes
162 makes the innermost call to EV::loop return. 256 the innermost call to EV::run return.
163 257
164 When called with an argument of EV::UNLOOP_ALL, all calls to 258 When called with an argument of EV::BREAK_ALL, all calls to EV::run
165 EV::loop will return as fast as possible. 259 will return as fast as possible.
166 260
167 $count = EV::loop_count 261 When called with an argument of EV::BREAK_CANCEL, any pending break
168 $count = $loop->loop_count 262 will be cancelled.
263
264 $count = EV::iteration
265 $count = $loop->iteration
169 Return the number of times the event loop has polled for new events. 266 Return the number of times the event loop has polled for new events.
170 Sometiems useful as a generation counter. 267 Sometimes useful as a generation counter.
171 268
172 EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 269 EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
173 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 270 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
174 This function rolls together an I/O and a timer watcher for a single 271 This function rolls together an I/O and a timer watcher for a single
175 one-shot event without the need for managing a watcher object. 272 one-shot event without the need for managing a watcher object.
… …
179 "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
180 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
181 "undef" for $fh_or_undef and 0 for $events). 278 "undef" for $fh_or_undef and 0 for $events).
182 279
183 If timeout is "undef" or negative, then there will be no timeout. 280 If timeout is "undef" or negative, then there will be no timeout.
184 Otherwise a EV::timer with this value will be started. 281 Otherwise an "EV::timer" with this value will be started.
185 282
186 When an error occurs or either the timeout or I/O watcher triggers, 283 When an error occurs or either the timeout or I/O watcher triggers,
187 then the callback will be called with the received event set (in 284 then the callback will be called with the received event set (in
188 general you can expect it to be a combination of "EV::ERROR", 285 general you can expect it to be a combination of "EV::ERROR",
189 "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). 286 "EV::READ", "EV::WRITE" and "EV::TIMER").
190 287
191 EV::once doesn't return anything: the watchers stay active till 288 EV::once doesn't return anything: the watchers stay active till
192 either of them triggers, then they will be stopped and freed, and 289 either of them triggers, then they will be stopped and freed, and
193 the callback invoked. 290 the callback invoked.
194 291
195 EV::feed_fd_event ($fd, $revents) 292 EV::feed_fd_event $fd, $revents
196 $loop->feed_fd_event ($fd, $revents) 293 $loop->feed_fd_event ($fd, $revents)
197 Feed an event on a file descriptor into EV. EV will react to this 294 Feed an event on a file descriptor into EV. EV will react to this
198 call as if the readyness notifications specified by $revents (a 295 call as if the readyness notifications specified by $revents (a
199 combination of "EV::READ" and "EV::WRITE") happened on the file 296 combination of "EV::READ" and "EV::WRITE") happened on the file
200 descriptor $fd. 297 descriptor $fd.
201 298
202 EV::feed_signal_event ($signal) 299 EV::feed_signal_event $signal
203 Feed a signal event into EV. EV will react to this call as if the 300 Feed a signal event into the default loop. EV will react to this
204 signal specified by $signal had occured. 301 call as if the signal specified by $signal had occured.
302
303 EV::feed_signal $signal
304 Feed a signal event into EV - unlike "EV::feed_signal_event", this
305 works regardless of which loop has registered the signal, and is
306 mainly useful for custom signal implementations.
205 307
206 EV::set_io_collect_interval $time 308 EV::set_io_collect_interval $time
207 $loop->set_io_collect_interval ($time) 309 $loop->set_io_collect_interval ($time)
208 EV::set_timeout_collect_interval $time 310 EV::set_timeout_collect_interval $time
209 $loop->set_timeout_collect_interval ($time) 311 $loop->set_timeout_collect_interval ($time)
210 These advanced functions set the minimum block interval when polling 312 These advanced functions set the minimum block interval when polling
211 for I/O events and the minimum wait interval for timer events. See 313 for I/O events and the minimum wait interval for timer events. See
212 the libev documentation at 314 the libev documentation at
213 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT 315 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT
214 ROLLING_THE_EVENT_LOOP> for a more detailed discussion. 316 ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more
317 detailed discussion.
318
319 $count = EV::pending_count
320 $count = $loop->pending_count
321 Returns the number of currently pending watchers.
322
323 EV::invoke_pending
324 $loop->invoke_pending
325 Invoke all currently pending watchers.
215 326
216WATCHER OBJECTS 327WATCHER OBJECTS
217 A watcher is an object that gets created to record your interest in some 328 A watcher is an object that gets created to record your interest in some
218 event. For instance, if you want to wait for STDIN to become readable, 329 event. For instance, if you want to wait for STDIN to become readable,
219 you would create an EV::io watcher for that: 330 you would create an EV::io watcher for that:
220 331
221 my $watcher = EV::io *STDIN, EV::READ, sub { 332 my $watcher = EV::io *STDIN, EV::READ, sub {
222 my ($watcher, $revents) = @_; 333 my ($watcher, $revents) = @_;
223 warn "yeah, STDIN should now be readable without blocking!\n" 334 warn "yeah, STDIN should now be readable without blocking!\n"
224 }; 335 };
225 336
226 All watchers can be active (waiting for events) or inactive (paused). 337 All watchers can be active (waiting for events) or inactive (paused).
227 Only active watchers will have their callbacks invoked. All callbacks 338 Only active watchers will have their callbacks invoked. All callbacks
228 will be called with at least two arguments: the watcher and a bitmask of 339 will be called with at least two arguments: the watcher and a bitmask of
229 received events. 340 received events.
230 341
231 Each watcher type has its associated bit in revents, so you can use the 342 Each watcher type has its associated bit in revents, so you can use the
232 same callback for multiple watchers. The event mask is named after the 343 same callback for multiple watchers. The event mask is named after the
233 type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 344 type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
234 EV::periodic sets EV::PERIODIC and so on, with the exception of I/O 345 EV::periodic sets EV::PERIODIC and so on, with the exception of I/O
235 events (which can set both EV::READ and EV::WRITE bits), and EV::timer 346 events (which can set both EV::READ and EV::WRITE bits).
236 (which uses EV::TIMEOUT).
237 347
238 In the rare case where one wants to create a watcher but not start it at 348 In the rare case where one wants to create a watcher but not start it at
239 the same time, each constructor has a variant with a trailing "_ns" in 349 the same time, each constructor has a variant with a trailing "_ns" in
240 its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. 350 its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
241 351
… …
304 If the watcher is pending, this function clears its pending status 414 If the watcher is pending, this function clears its pending status
305 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
306 the watcher isn't pending it does nothing and returns 0. 416 the watcher isn't pending it does nothing and returns 0.
307 417
308 $previous_state = $w->keepalive ($bool) 418 $previous_state = $w->keepalive ($bool)
309 Normally, "EV::loop" will return when there are no active watchers 419 Normally, "EV::run" will return when there are no active watchers
310 (which is a "deadlock" because no progress can be made anymore). 420 (which is a "deadlock" because no progress can be made anymore).
311 This is convinient because it allows you to start your watchers (and 421 This is convenient because it allows you to start your watchers (and
312 your jobs), call "EV::loop" once and when it returns you know that 422 your jobs), call "EV::run" once and when it returns you know that
313 all your jobs are finished (or they forgot to register some watchers 423 all your jobs are finished (or they forgot to register some watchers
314 for their task :). 424 for their task :).
315 425
316 Sometimes, however, this gets in your way, for example when the 426 Sometimes, however, this gets in your way, for example when the
317 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
318 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
319 module written by somebody else even). Then you might want any 429 module written by somebody else even). Then you might want any
320 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
321 "EV::loop" from returning just because you happen to have this 431 "EV::run" from returning just because you happen to have this
322 long-running UDP port watcher. 432 long-running UDP port watcher.
323 433
324 In this case you can clear the keepalive status, which means that 434 In this case you can clear the keepalive status, which means that
325 even though your watcher is active, it won't keep "EV::loop" from 435 even though your watcher is active, it won't keep "EV::run" from
326 returning. 436 returning.
327 437
328 The initial value for keepalive is true (enabled), and you cna 438 The initial value for keepalive is true (enabled), and you can
329 change it any time. 439 change it any time.
330 440
331 Example: Register an I/O watcher for some UDP socket but do not keep 441 Example: Register an I/O watcher for some UDP socket but do not keep
332 the event loop from running just because of that watcher. 442 the event loop from running just because of that watcher.
333 443
334 my $udp_socket = ... 444 my $udp_socket = ...
335 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 445 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
336 $1000udp_watcher->keepalive (0); 446 $udp_watcher->keepalive (0);
337 447
338 $loop = $w->loop 448 $loop = $w->loop
339 Return the loop that this watcher is attached to. 449 Return the loop that this watcher is attached to.
340 450
341WATCHER TYPES 451WATCHER TYPES
… …
372 TIMER WATCHERS - relative and optionally repeating timeouts 482 TIMER WATCHERS - relative and optionally repeating timeouts
373 $w = EV::timer $after, $repeat, $callback 483 $w = EV::timer $after, $repeat, $callback
374 $w = EV::timer_ns $after, $repeat, $callback 484 $w = EV::timer_ns $after, $repeat, $callback
375 $w = $loop->timer ($after, $repeat, $callback) 485 $w = $loop->timer ($after, $repeat, $callback)
376 $w = $loop->timer_ns ($after, $repeat, $callback) 486 $w = $loop->timer_ns ($after, $repeat, $callback)
377 Calls the callback after $after seconds (which may be fractional). 487 Calls the callback after $after seconds (which may be fractional or
378 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
379 $repeat value as $after) after the callback returns. 489 the $repeat value as $after) after the callback returns.
380 490
381 This means that the callback would be called roughly after $after 491 This means that the callback would be called roughly after $after
382 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
383 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
384 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
… …
391 the same time. 501 the same time.
392 502
393 The "timer_ns" variant doesn't start (activate) the newly created 503 The "timer_ns" variant doesn't start (activate) the newly created
394 watcher. 504 watcher.
395 505
396 $w->set ($after, $repeat) 506 $w->set ($after, $repeat = 0)
397 Reconfigures the watcher, see the constructor above for details. Can 507 Reconfigures the watcher, see the constructor above for details. Can
398 be called at any time. 508 be called at any time.
399 509
400 $w->again 510 $w->again
511 $w->again ($repeat)
401 Similar to the "start" method, but has special semantics for 512 Similar to the "start" method, but has special semantics for
402 repeating timers: 513 repeating timers:
403 514
404 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.
405 516
… …
413 524
414 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
415 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
416 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"
417 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.
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.
418 542
419 PERIODIC WATCHERS - to cron or not to cron? 543 PERIODIC WATCHERS - to cron or not to cron?
420 $w = EV::periodic $at, $interval, $reschedule_cb, $callback 544 $w = EV::periodic $at, $interval, $reschedule_cb, $callback
421 $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 545 $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
422 $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback) 546 $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
… …
439 system time reaches or surpasses this time. 563 system time reaches or surpasses this time.
440 564
441 * repeating interval timer ($interval > 0, $reschedule_cb = 0) 565 * repeating interval timer ($interval > 0, $reschedule_cb = 0)
442 566
443 In this mode the watcher will always be scheduled to time out at 567 In this mode the watcher will always be scheduled to time out at
444 the next "$at + N * $interval" time (for some integer N) and 568 the next "$at + N * $interval" time (for the lowest integer N)
445 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.
446 571
447 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
448 to system time: 573 to system time:
449 574
450 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; 575 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
451 576
452 That doesn't mean there will always be 3600 seconds in between 577 That doesn't mean there will always be 3600 seconds in between
453 triggers, but only that the the clalback will be called when the 578 triggers, but only that the the callback will be called when the
454 system time shows a full hour (UTC). 579 system time shows a full hour (UTC).
455 580
456 Another way to think about it (for the mathematically inclined) 581 Another way to think about it (for the mathematically inclined)
457 is that EV::periodic will try to run the callback in this mode 582 is that EV::periodic will try to run the callback in this mode
458 at the next possible time where "$time = $at (mod $interval)", 583 at the next possible time where "$time = $at (mod $interval)",
… …
466 first, and the current time as second argument. 591 first, and the current time as second argument.
467 592
468 *This callback MUST NOT stop or destroy this or any other 593 *This callback MUST NOT stop or destroy this or any other
469 periodic watcher, ever, and MUST NOT call any event loop 594 periodic watcher, ever, and MUST NOT call any event loop
470 functions or methods*. If you need to stop it, return 1e30 and 595 functions or methods*. If you need to stop it, return 1e30 and
471 stop it afterwards. You may create and start a "EV::prepare" 596 stop it afterwards. You may create and start an "EV::prepare"
472 watcher for this task. 597 watcher for this task.
473 598
474 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
475 time value (that is, the lowest time value larger than or equal 600 time value (that is, the lowest time value larger than or equal
476 to to the second argument). It will usually be called just 601 to to the second argument). It will usually be called just
477 before the callback will be triggered, but might be called at 602 before the callback will be triggered, but might be called at
478 other times, too. 603 other times, too.
479 604
480 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
481 that triggers on each midnight, local time (actually 24 hours 606 that triggers on each midnight, local time (actually one day
482 after the last midnight, to keep the example simple. If you know 607 after the last midnight, to keep the example simple):
483 a way to do it correctly in about the same space (without
484 requiring elaborate modules), drop me a note :):
485 608
486 my $daily = EV::periodic 0, 0, sub { 609 my $daily = EV::periodic 0, 0, sub {
487 my ($w, $now) = @_; 610 my ($w, $now) = @_;
488 611
489 use Time::Local (); 612 use Time::Local ();
490 my (undef, undef, undef, $d, $m, $y) = localtime $now; 613 my (undef, undef, undef, $d, $m, $y) = localtime $now;
491 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y 614 Time::Local::timelocal_nocheck 0, 0, 0, $d + 1, $m, $y
492 }, sub { 615 }, sub {
493 print "it's midnight or likely shortly after, now\n"; 616 print "it's midnight or likely shortly after, now\n";
494 }; 617 };
495 618
496 The "periodic_ns" variant doesn't start (activate) the newly created 619 The "periodic_ns" variant doesn't start (activate) the newly created
… …
504 Simply stops and starts the watcher again. 627 Simply stops and starts the watcher again.
505 628
506 $time = $w->at 629 $time = $w->at
507 Return the time that the watcher is expected to trigger next. 630 Return the time that the watcher is expected to trigger next.
508 631
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
509 SIGNAL WATCHERS - signal me when a signal gets signalled! 647 SIGNAL WATCHERS - signal me when a signal gets signalled!
510 $w = EV::signal $signal, $callback 648 $w = EV::signal $signal, $callback
511 $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)
512 Call the callback when $signal is received (the signal can be 652 Call the callback when $signal is received (the signal can be
513 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.
514 658
515 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
516 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
517 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
518 when you add/remove callbacks to %SIG, so watch out. 662 when you add/remove callbacks to %SIG, so watch out.
… …
692 $w = $loop->check_ns ($callback) 836 $w = $loop->check_ns ($callback)
693 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
694 has gathered events), but before any other callbacks have been 838 has gathered events), but before any other callbacks have been
695 invoked. 839 invoked.
696 840
697 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
698 mainloop: You register a prepare callback and in there, you create 842 mainloop: You register a prepare callback and in there, you create
699 io and timer watchers as required by the other software. Here is a 843 io and timer watchers as required by the other software. Here is a
700 real-world example of integrating Net::SNMP (with some details left 844 real-world example of integrating Net::SNMP (with some details left
701 out): 845 out):
702 846
… …
733 # make the dispatcher handle any new stuff 877 # make the dispatcher handle any new stuff
734 ... not shown 878 ... not shown
735 }; 879 };
736 880
737 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
738 watchers are destroyed before this cna happen (remember EV::check 882 watchers are destroyed before this can happen (remember EV::check
739 gets called first). 883 gets called first).
740 884
741 The "check_ns" variant doesn't start (activate) the newly created 885 The "check_ns" variant doesn't start (activate) the newly created
742 watcher. 886 watcher.
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.
743 896
744 FORK WATCHERS - the audacity to resume the event loop after a fork 897 FORK WATCHERS - the audacity to resume the event loop after a fork
745 Fork watchers are called when a "fork ()" was detected. The invocation 898 Fork watchers are called when a "fork ()" was detected. The invocation
746 is done before the event loop blocks next and before "check" watchers 899 is done before the event loop blocks next and before "check" watchers
747 are being called, and only in the child after the fork. 900 are being called, and only in the child after the fork.
… …
762 embedded loop, other types of watchers might be handled in a delayed or 915 embedded loop, other types of watchers might be handled in a delayed or
763 incorrect fashion and must not be used). 916 incorrect fashion and must not be used).
764 917
765 See the libev documentation at 918 See the libev documentation at
766 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code 919 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code
767 _when_one_backend_> for more details. 920 _when_one_backend_> (locally installed as EV::libev) for more details.
768 921
769 In short, this watcher is most useful on BSD systems without working 922 In short, this watcher is most useful on BSD systems without working
770 kqueue to still be able to handle a large number of sockets: 923 kqueue to still be able to handle a large number of sockets:
771 924
772 my $socket_loop; 925 my $socket_loop;
773 926
774 # check wether we use SELECT or POLL _and_ KQUEUE is supported 927 # check wether we use SELECT or POLL _and_ KQUEUE is supported
775 if ( 928 if (
776 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 929 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
777 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 930 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
778 ) { 931 ) {
779 # use kqueue for sockets 932 # use kqueue for sockets
780 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 933 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
781 } 934 }
782 935
783 # use the default loop otherwise 936 # use the default loop otherwise
784 $socket_loop ||= EV::default_loop; 937 $socket_loop ||= EV::default_loop;
785 938
786 $w = EV::embed $otherloop, $callback 939 $w = EV::embed $otherloop[, $callback]
787 $w = EV::embed_ns $otherloop, $callback 940 $w = EV::embed_ns $otherloop[, $callback]
788 $w = $loop->embed ($otherloop, $callback) 941 $w = $loop->embed ($otherloop[, $callback])
789 $w = $loop->embed_ns ($otherloop, $callback) 942 $w = $loop->embed_ns ($otherloop[, $callback])
790 Call the callback when the embedded event loop ($otherloop) has any 943 Call the callback when the embedded event loop ($otherloop) has any
791 I/O activity. The $callback should alwas be specified as "undef" in 944 I/O activity. The $callback is optional: if it is missing, then the
792 this version of EV, which means the embedded event loop will be 945 embedded event loop will be managed automatically (which is
793 managed automatically. 946 recommended), otherwise you have to invoke "sweep" yourself.
794 947
795 The "embed_ns" variant doesn't start (activate) the newly created 948 The "embed_ns" variant doesn't start (activate) the newly created
796 watcher. 949 watcher.
797 950
798 ASYNC WATCHERS - how to wake up another event loop 951 ASYNC WATCHERS - how to wake up another event loop
799 Async watchers are provided by EV, but have little use in perl directly, 952 Async watchers are provided by EV, but have little use in perl directly,
800 as perl neither supports threads nor direct access to signal handlers or 953 as perl neither supports threads running in parallel nor direct access
801 other contexts where they could be of value. 954 to signal handlers or other contexts where they could be of value.
802 955
803 It is, however, possible to use them from the XS level. 956 It is, however, possible to use them from the XS level.
804 957
805 Please see the libev documentation for further details. 958 Please see the libev documentation for further details.
806 959
807 $w = EV::async $callback 960 $w = EV::async $callback
808 $w = EV::async_ns $callback 961 $w = EV::async_ns $callback
962 $w = $loop->async ($callback)
963 $w = $loop->async_ns ($callback)
809 $w->send 964 $w->send
810 $bool = $w->async_pending 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.
811 970
812PERL SIGNALS 971PERL SIGNALS
813 While Perl signal handling (%SIG) is not affected by EV, the behaviour 972 While Perl signal handling (%SIG) is not affected by EV, the behaviour
814 with EV is as the same as any other C library: Perl-signals will only be 973 with EV is as the same as any other C library: Perl-signals will only be
815 handled when Perl runs, which means your signal handler might be invoked 974 handled when Perl runs, which means your signal handler might be invoked
… …
825 my $async_check = EV::check sub { }; 984 my $async_check = EV::check sub { };
826 985
827 This ensures that perl gets into control for a short time to handle any 986 This ensures that perl gets into control for a short time to handle any
828 pending signals, and also ensures (slightly) slower overall operation. 987 pending signals, and also ensures (slightly) slower overall operation.
829 988
830THREADS 989ITHREADS
831 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
832 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
833 work on thread support for it. 992 Coro are fully supported (and enhanced support is available via
993 Coro::EV).
834 994
835FORK 995FORK
836 Most of the "improved" event delivering mechanisms of modern operating 996 Most of the "improved" event delivering mechanisms of modern operating
837 systems have quite a few problems with fork(2) (to put it bluntly: it is 997 systems have quite a few problems with fork(2) (to put it bluntly: it is
838 not supported and usually destructive). Libev makes it possible to work 998 not supported and usually destructive). Libev makes it possible to work
… …
848 1008
849 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
850 course. 1010 course.
851 1011
852SEE ALSO 1012SEE ALSO
853 EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event 1013 EV::MakeMaker - MakeMaker interface to XS API, EV::ADNS (asynchronous
854 loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines 1014 DNS), Glib::EV (makes Glib/Gtk2 use EV as event loop), EV::Glib (embed
855 with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop 1015 Glib into EV), Coro::EV (efficient thread integration), Net::SNMP::EV
856 agnostic and portable event driven programming. 1016 (asynchronous SNMP), AnyEvent for event-loop agnostic and portable event
1017 driven programming.
857 1018
858AUTHOR 1019AUTHOR
859 Marc Lehmann <schmorp@schmorp.de> 1020 Marc Lehmann <schmorp@schmorp.de>
860 http://home.schmorp.de/ 1021 http://home.schmorp.de/
861 1022

Diff Legend

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