1 | =head1 NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | EV - perl interface to libevent, monkey.org/~provos/libevent/ |
3 | EV - perl interface to libev, a high performance full-featured event loop |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use EV; |
7 | use EV; |
8 | |
8 | |
9 | # TIMER |
9 | # TIMERS |
10 | |
10 | |
11 | my $w = EV::timer 2, 0, sub { |
11 | my $w = EV::timer 2, 0, sub { |
12 | warn "is called after 2s"; |
12 | warn "is called after 2s"; |
13 | }; |
13 | }; |
14 | |
14 | |
15 | my $w = EV::timer 2, 1, sub { |
15 | my $w = EV::timer 2, 2, sub { |
16 | warn "is called roughly every 2s (repeat = 1)"; |
16 | warn "is called roughly every 2s (repeat = 2)"; |
17 | }; |
17 | }; |
18 | |
18 | |
19 | undef $w; # destroy event watcher again |
19 | undef $w; # destroy event watcher again |
20 | |
20 | |
21 | # IO |
|
|
22 | |
|
|
23 | my $w = EV::timer_abs 0, 60, sub { |
21 | my $w = EV::periodic 0, 60, 0, sub { |
24 | warn "is called every minute, on the minute, exactly"; |
22 | warn "is called every minute, on the minute, exactly"; |
25 | }; |
23 | }; |
26 | |
24 | |
|
|
25 | # IO |
|
|
26 | |
27 | my $w = EV::io \*STDIN, EV::READ | EV::PERSIST, sub { |
27 | my $w = EV::io *STDIN, EV::READ, sub { |
28 | my ($w, $events) = @_; # all callbacks get the watcher object and event mask |
28 | my ($w, $revents) = @_; # all callbacks receive the watcher and event mask |
29 | if ($events & EV::TIMEOUT) { |
|
|
30 | warn "nothing received on stdin for 10 seconds, retrying"; |
|
|
31 | } else { |
|
|
32 | warn "stdin is readable, you entered: ", <STDIN>; |
29 | warn "stdin is readable, you entered: ", <STDIN>; |
33 | } |
|
|
34 | }; |
30 | }; |
35 | $w->timeout (10); |
31 | |
|
|
32 | # SIGNALS |
|
|
33 | |
|
|
34 | my $w = EV::signal 'QUIT', sub { |
|
|
35 | warn "sigquit received\n"; |
|
|
36 | }; |
|
|
37 | |
|
|
38 | # CHILD/PID STATUS CHANGES |
36 | |
39 | |
|
|
40 | my $w = EV::child 666, sub { |
|
|
41 | my ($w, $revents) = @_; |
|
|
42 | my $status = $w->rstatus; |
|
|
43 | }; |
|
|
44 | |
37 | # MAINLOOP |
45 | # MAINLOOP |
38 | EV::dispatch; # loop as long as watchers are active |
46 | EV::loop; # loop until EV::unloop is called or all watchers stop |
39 | EV::loop; # the same thing |
47 | EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled |
40 | EV::loop EV::LOOP_ONCE; |
48 | EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block |
41 | EV::loop EV::LOOP_ONSHOT; |
|
|
42 | |
49 | |
43 | =head1 DESCRIPTION |
50 | =head1 DESCRIPTION |
44 | |
51 | |
45 | This module provides an interface to libevent |
52 | This module provides an interface to libev |
46 | (L<http://monkey.org/~provos/libevent/>). You probably should acquaint |
53 | (L<http://software.schmorp.de/pkg/libev.html>). |
47 | yourself with its documentation and source code to be able to use this |
|
|
48 | module fully. |
|
|
49 | |
|
|
50 | Please note thta this module disables the libevent EPOLL method by |
|
|
51 | default, see BUGS, below, if you need to enable it. |
|
|
52 | |
54 | |
53 | =cut |
55 | =cut |
54 | |
56 | |
55 | package EV; |
57 | package EV; |
56 | |
58 | |
57 | use strict; |
59 | use strict; |
58 | |
60 | |
59 | BEGIN { |
61 | BEGIN { |
60 | our $VERSION = '0.02'; |
62 | our $VERSION = '1.3'; |
61 | use XSLoader; |
63 | use XSLoader; |
62 | XSLoader::load "EV", $VERSION; |
64 | XSLoader::load "EV", $VERSION; |
63 | } |
65 | } |
64 | |
66 | |
|
|
67 | @EV::IO::ISA = |
|
|
68 | @EV::Timer::ISA = |
|
|
69 | @EV::Periodic::ISA = |
|
|
70 | @EV::Signal::ISA = |
|
|
71 | @EV::Idle::ISA = |
|
|
72 | @EV::Prepare::ISA = |
|
|
73 | @EV::Check::ISA = |
|
|
74 | @EV::Child::ISA = "EV::Watcher"; |
|
|
75 | |
65 | =head1 BASIC INTERFACE |
76 | =head1 BASIC INTERFACE |
66 | |
77 | |
67 | =over 4 |
78 | =over 4 |
68 | |
|
|
69 | =item $EV::NPRI |
|
|
70 | |
|
|
71 | How many priority levels are available. |
|
|
72 | |
79 | |
73 | =item $EV::DIED |
80 | =item $EV::DIED |
74 | |
81 | |
75 | Must contain a reference to a function that is called when a callback |
82 | Must contain a reference to a function that is called when a callback |
76 | throws an exception (with $@ containing thr error). The default prints an |
83 | throws an exception (with $@ containing thr error). The default prints an |
77 | informative message and continues. |
84 | informative message and continues. |
78 | |
85 | |
79 | If this callback throws an exception it will be silently ignored. |
86 | If this callback throws an exception it will be silently ignored. |
80 | |
87 | |
|
|
88 | =item $time = EV::time |
|
|
89 | |
|
|
90 | Returns the current time in (fractional) seconds since the epoch. |
|
|
91 | |
81 | =item $time = EV::now |
92 | =item $time = EV::now |
82 | |
93 | |
83 | Returns the time in (fractional) seconds since the epoch. |
94 | Returns the time the last event loop iteration has been started. This |
84 | |
95 | is the time that (relative) timers are based on, and refering to it is |
85 | =item $version = EV::version |
96 | usually faster then calling EV::time. |
86 | |
97 | |
87 | =item $method = EV::method |
98 | =item $method = EV::method |
88 | |
99 | |
89 | Return version string and event polling method used. |
100 | Returns an integer describing the backend used by libev (EV::METHOD_SELECT |
|
|
101 | or EV::METHOD_EPOLL). |
90 | |
102 | |
91 | =item EV::loop $flags # EV::LOOP_ONCE, EV::LOOP_ONESHOT |
103 | =item EV::loop [$flags] |
92 | |
104 | |
93 | =item EV::loopexit $after |
105 | Begin checking for events and calling callbacks. It returns when a |
|
|
106 | callback calls EV::unloop. |
94 | |
107 | |
95 | Exit any active loop or dispatch after C<$after> seconds or immediately if |
108 | The $flags argument can be one of the following: |
96 | C<$after> is missing or zero. |
|
|
97 | |
109 | |
98 | =item EV::dispatch |
110 | 0 as above |
|
|
111 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
|
|
112 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
99 | |
113 | |
100 | Same as C<EV::loop 0>. |
114 | =item EV::unloop [$how] |
101 | |
115 | |
102 | =item EV::event $callback |
116 | When called with no arguments or an argument of EV::UNLOOP_ONE, makes the |
|
|
117 | innermost call to EV::loop return. |
103 | |
118 | |
104 | Creates a new event watcher waiting for nothing, calling the given callback. |
119 | When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as |
|
|
120 | fast as possible. |
105 | |
121 | |
|
|
122 | =item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
|
|
123 | |
|
|
124 | This function rolls together an I/O and a timer watcher for a single |
|
|
125 | one-shot event without the need for managing a watcher object. |
|
|
126 | |
|
|
127 | If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> |
|
|
128 | must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ |
|
|
129 | | EV::WRITE>, indicating the type of I/O event you want to wait for. If |
|
|
130 | you do not want to wait for some I/O event, specify C<undef> for |
|
|
131 | C<$fh_or_undef> and C<0> for C<$events>). |
|
|
132 | |
|
|
133 | If timeout is C<undef> or negative, then there will be no |
|
|
134 | timeout. Otherwise a EV::timer with this value will be started. |
|
|
135 | |
|
|
136 | When an error occurs or either the timeout or I/O watcher triggers, then |
|
|
137 | the callback will be called with the received event set (in general |
|
|
138 | you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>, |
|
|
139 | C<EV::WRITE> and C<EV::TIMEOUT>). |
|
|
140 | |
|
|
141 | EV::once doesn't return anything: the watchers stay active till either |
|
|
142 | of them triggers, then they will be stopped and freed, and the callback |
|
|
143 | invoked. |
|
|
144 | |
|
|
145 | =back |
|
|
146 | |
|
|
147 | =head2 WATCHER |
|
|
148 | |
|
|
149 | A watcher is an object that gets created to record your interest in some |
|
|
150 | event. For instance, if you want to wait for STDIN to become readable, you |
|
|
151 | would create an EV::io watcher for that: |
|
|
152 | |
|
|
153 | my $watcher = EV::io *STDIN, EV::READ, sub { |
|
|
154 | my ($watcher, $revents) = @_; |
|
|
155 | warn "yeah, STDIN should not be readable without blocking!\n" |
|
|
156 | }; |
|
|
157 | |
|
|
158 | All watchers can be active (waiting for events) or inactive (paused). Only |
|
|
159 | active watchers will have their callbacks invoked. All callbacks will be |
|
|
160 | called with at least two arguments: the watcher and a bitmask of received |
|
|
161 | events. |
|
|
162 | |
|
|
163 | Each watcher type has its associated bit in revents, so you can use the |
|
|
164 | same callback for multiple watchers. The event mask is named after the |
|
|
165 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
|
|
166 | EV::periodic sets EV::PERIODIC and so on, with the exception of IO events |
|
|
167 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
|
|
168 | uses EV::TIMEOUT). |
|
|
169 | |
|
|
170 | In the rare case where one wants to create a watcher but not start it at |
|
|
171 | the same time, each constructor has a variant with a trailing C<_ns> in |
|
|
172 | its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. |
|
|
173 | |
|
|
174 | Please note that a watcher will automatically be stopped when the watcher |
|
|
175 | object is destroyed, so you I<need> to keep the watcher objects returned by |
|
|
176 | the constructors. |
|
|
177 | |
|
|
178 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
|
|
179 | ->fh and so on) automatically stop and start it again if it is active, |
|
|
180 | which means pending events get lost. |
|
|
181 | |
|
|
182 | =head2 WATCHER TYPES |
|
|
183 | |
|
|
184 | Now lets move to the existing watcher types and asociated methods. |
|
|
185 | |
|
|
186 | The following methods are available for all watchers. Then followes a |
|
|
187 | description of each watcher constructor (EV::io, EV::timer, EV::periodic, |
|
|
188 | EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by |
|
|
189 | any type-specific methods (if any). |
|
|
190 | |
|
|
191 | =over 4 |
|
|
192 | |
|
|
193 | =item $w->start |
|
|
194 | |
|
|
195 | Starts a watcher if it isn't active already. Does nothing to an already |
|
|
196 | active watcher. By default, all watchers start out in the active state |
|
|
197 | (see the description of the C<_ns> variants if you need stopped watchers). |
|
|
198 | |
|
|
199 | =item $w->stop |
|
|
200 | |
|
|
201 | Stop a watcher if it is active. Also clear any pending events (events that |
|
|
202 | have been received but that didn't yet result in a callback invocation), |
|
|
203 | regardless of wether the watcher was active or not. |
|
|
204 | |
|
|
205 | =item $bool = $w->is_active |
|
|
206 | |
|
|
207 | Returns true if the watcher is active, false otherwise. |
|
|
208 | |
|
|
209 | =item $current_data = $w->data |
|
|
210 | |
|
|
211 | =item $old_data = $w->data ($new_data) |
|
|
212 | |
|
|
213 | Queries a freely usable data scalar on the watcher and optionally changes |
|
|
214 | it. This is a way to associate custom data with a watcher: |
|
|
215 | |
|
|
216 | my $w = EV::timer 60, 0, sub { |
|
|
217 | warn $_[0]->data; |
|
|
218 | }; |
|
|
219 | $w->data ("print me!"); |
|
|
220 | |
|
|
221 | =item $current_cb = $w->cb |
|
|
222 | |
|
|
223 | =item $old_cb = $w->cb ($new_cb) |
|
|
224 | |
|
|
225 | Queries the callback on the watcher and optionally changes it. You can do |
|
|
226 | this at any time without the watcher restarting. |
|
|
227 | |
|
|
228 | =item $current_priority = $w->priority |
|
|
229 | |
|
|
230 | =item $old_priority = $w->priority ($new_priority) |
|
|
231 | |
|
|
232 | Queries the priority on the watcher and optionally changes it. Pending |
|
|
233 | watchers with higher priority will be invoked first. The valid range of |
|
|
234 | priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default |
|
|
235 | -2). If the priority is outside this range it will automatically be |
|
|
236 | normalised to the nearest valid priority. |
|
|
237 | |
|
|
238 | The default priority of any newly-created watcher is 0. |
|
|
239 | |
|
|
240 | Note that the priority semantics have not yet been fleshed out and are |
|
|
241 | subject to almost certain change. |
|
|
242 | |
|
|
243 | =item $w->trigger ($revents) |
|
|
244 | |
|
|
245 | Call the callback *now* with the given event mask. |
|
|
246 | |
|
|
247 | =item $previous_state = $w->keepalive ($bool) |
|
|
248 | |
|
|
249 | Normally, C<EV::loop> will return when there are no active watchers |
|
|
250 | (which is a "deadlock" because no progress can be made anymore). This is |
|
|
251 | convinient because it allows you to start your watchers (and your jobs), |
|
|
252 | call C<EV::loop> once and when it returns you know that all your jobs are |
|
|
253 | finished (or they forgot to register some watchers for their task :). |
|
|
254 | |
|
|
255 | Sometimes, however, this gets in your way, for example when you the module |
|
|
256 | that calls C<EV::loop> (usually the main program) is not the same module |
|
|
257 | as a long-living watcher (for example a DNS client module written by |
|
|
258 | somebody else even). Then you might want any outstanding requests to be |
|
|
259 | handled, but you would not want to keep C<EV::loop> from returning just |
|
|
260 | because you happen to have this long-running UDP port watcher. |
|
|
261 | |
|
|
262 | In this case you can clear the keepalive status, which means that even |
|
|
263 | though your watcher is active, it won't keep C<EV::loop> from returning. |
|
|
264 | |
|
|
265 | The initial value for keepalive is true (enabled), and you cna change it |
|
|
266 | any time. |
|
|
267 | |
|
|
268 | Example: Register an IO watcher for some UDP socket but do not keep the |
|
|
269 | event loop from running just because of that watcher. |
|
|
270 | |
|
|
271 | my $udp_socket = ... |
|
|
272 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
|
|
273 | $udp_watcher->keepalive (0); |
|
|
274 | |
106 | =item my $w = EV::io $fileno_or_fh, $eventmask, $callback |
275 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
107 | |
276 | |
108 | =item my $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
277 | =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
109 | |
278 | |
110 | As long as the returned watcher object is alive, call the C<$callback> |
279 | As long as the returned watcher object is alive, call the C<$callback> |
111 | when the events specified in C<$eventmask> happen. Initially, the timeout |
280 | when the events specified in C<$eventmask>. |
112 | is disabled. |
|
|
113 | |
281 | |
114 | You can additionall set a timeout to occur on the watcher, but note that |
|
|
115 | this timeout will not be reset when you get an I/O event in the EV::PERSIST |
|
|
116 | case, and reaching a timeout will always stop the watcher even in the |
|
|
117 | EV::PERSIST case. |
|
|
118 | |
|
|
119 | If you want a timeout to occur only after a specific time of inactivity, set |
|
|
120 | a repeating timeout and do NOT use EV::PERSIST. |
|
|
121 | |
|
|
122 | Eventmask can be one or more of these constants ORed together: |
282 | The $eventmask can be one or more of these constants ORed together: |
123 | |
283 | |
124 | EV::READ wait until read() wouldn't block anymore |
284 | EV::READ wait until read() wouldn't block anymore |
125 | EV::WRITE wait until write() wouldn't block anymore |
285 | EV::WRITE wait until write() wouldn't block anymore |
126 | EV::PERSIST stay active after a (non-timeout) event occured |
|
|
127 | |
286 | |
128 | The C<io_ns> variant doesn't add/start the newly created watcher. |
287 | The C<io_ns> variant doesn't start (activate) the newly created watcher. |
129 | |
288 | |
130 | =item my $w = EV::timed_io $fileno_or_fh, $eventmask, $timeout, $callback |
289 | =item $w->set ($fileno_or_fh, $eventmask) |
131 | |
290 | |
132 | =item my $w = EV::timed_io_ns $fileno_or_fh, $eventmask, $timeout, $callback |
291 | Reconfigures the watcher, see the constructor above for details. Can be |
|
|
292 | called at any time. |
133 | |
293 | |
134 | Same as C<io> and C<io_ns>, but also specifies a timeout (as if there was |
294 | =item $current_fh = $w->fh |
135 | a call to C<< $w->timeout ($timout, 1) >>. The persist flag is not allowed |
|
|
136 | and will automatically be cleared. The watcher will be restarted after each event. |
|
|
137 | |
295 | |
138 | If the timeout is zero or undef, no timeout will be set, and a normal |
296 | =item $old_fh = $w->fh ($new_fh) |
139 | watcher (with the persist flag set!) will be created. |
|
|
140 | |
297 | |
141 | This has the effect of timing out after the specified period of inactivity |
298 | Returns the previously set filehandle and optionally set a new one. |
142 | has happened. |
|
|
143 | |
299 | |
144 | Due to the design of libevent, this is also relatively inefficient, having |
300 | =item $current_eventmask = $w->events |
145 | one or two io watchers and a separate timeout watcher that you reset on |
|
|
146 | activity (by calling its C<start> method) is usually more efficient. |
|
|
147 | |
301 | |
|
|
302 | =item $old_eventmask = $w->events ($new_eventmask) |
|
|
303 | |
|
|
304 | Returns the previously set event mask and optionally set a new one. |
|
|
305 | |
|
|
306 | |
148 | =item my $w = EV::timer $after, $repeat, $callback |
307 | =item $w = EV::timer $after, $repeat, $callback |
149 | |
308 | |
150 | =item my $w = EV::timer_ns $after, $repeat, $callback |
309 | =item $w = EV::timer_ns $after, $repeat, $callback |
151 | |
310 | |
152 | Calls the callback after C<$after> seconds. If C<$repeat> is true, the |
311 | Calls the callback after C<$after> seconds. If C<$repeat> is non-zero, |
153 | timer will be restarted after the callback returns. This means that the |
312 | the timer will be restarted (with the $repeat value as $after) after the |
154 | callback would be called roughly every C<$after> seconds, prolonged by the |
313 | callback returns. |
155 | time the callback takes. |
|
|
156 | |
314 | |
|
|
315 | This means that the callback would be called roughly after C<$after> |
|
|
316 | seconds, and then every C<$repeat> seconds. The timer does his best not |
|
|
317 | to drift, but it will not invoke the timer more often then once per event |
|
|
318 | loop iteration, and might drift in other cases. If that isn't acceptable, |
|
|
319 | look at EV::periodic, which can provide long-term stable timers. |
|
|
320 | |
|
|
321 | The timer is based on a monotonic clock, that is, if somebody is sitting |
|
|
322 | in front of the machine while the timer is running and changes the system |
|
|
323 | clock, the timer will nevertheless run (roughly) the same time. |
|
|
324 | |
157 | The C<timer_ns> variant doesn't add/start the newly created watcher. |
325 | The C<timer_ns> variant doesn't start (activate) the newly created watcher. |
158 | |
326 | |
159 | =item my $w = EV::timer_abs $at, $interval, $callback |
327 | =item $w->set ($after, $repeat) |
160 | |
328 | |
161 | =item my $w = EV::timer_abs_ns $at, $interval, $callback |
329 | Reconfigures the watcher, see the constructor above for details. Can be at |
|
|
330 | any time. |
162 | |
331 | |
163 | Similar to EV::timer, but the time is given as an absolute point in time |
332 | =item $w->again |
164 | (C<$at>), plus an optional C<$interval>. |
|
|
165 | |
333 | |
166 | If the C<$interval> is zero, then the callback will be called at the time |
334 | Similar to the C<start> method, but has special semantics for repeating timers: |
167 | C<$at> if that is in the future, or as soon as possible if its in the |
|
|
168 | past. It will not automatically repeat. |
|
|
169 | |
335 | |
170 | If the C<$interval> is nonzero, then the watcher will always be scheduled |
336 | If the timer is active and non-repeating, it will be stopped. |
171 | to time out at the next C<$at + integer * $interval> time. |
|
|
172 | |
337 | |
173 | This can be used to schedule a callback to run at very regular intervals, |
338 | If the timer is active and repeating, reset the timeout to occur |
174 | as long as the processing time is less then the interval (otherwise |
339 | C<$repeat> seconds after now. |
175 | obviously events will be skipped). |
340 | |
|
|
341 | If the timer is inactive and repeating, start it using the repeat value. |
|
|
342 | |
|
|
343 | Otherwise do nothing. |
|
|
344 | |
|
|
345 | This behaviour is useful when you have a timeout for some IO |
|
|
346 | operation. You create a timer object with the same value for C<$after> and |
|
|
347 | C<$repeat>, and then, in the read/write watcher, run the C<again> method |
|
|
348 | on the timeout. |
|
|
349 | |
|
|
350 | |
|
|
351 | =item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
|
|
352 | |
|
|
353 | =item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
|
|
354 | |
|
|
355 | Similar to EV::timer, but is not based on relative timeouts but on |
|
|
356 | absolute times. Apart from creating "simple" timers that trigger "at" the |
|
|
357 | specified time, it can also be used for non-drifting absolute timers and |
|
|
358 | more complex, cron-like, setups that are not adversely affected by time |
|
|
359 | jumps (i.e. when the system clock is changed by explicit date -s or other |
|
|
360 | means such as ntpd). It is also the most complex watcher type in EV. |
|
|
361 | |
|
|
362 | It has three distinct "modes": |
|
|
363 | |
|
|
364 | =over 4 |
|
|
365 | |
|
|
366 | =item * absolute timer ($interval = $reschedule_cb = 0) |
|
|
367 | |
|
|
368 | This time simply fires at the wallclock time C<$at> and doesn't repeat. It |
|
|
369 | will not adjust when a time jump occurs, that is, if it is to be run |
|
|
370 | at January 1st 2011 then it will run when the system time reaches or |
|
|
371 | surpasses this time. |
|
|
372 | |
|
|
373 | =item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) |
|
|
374 | |
|
|
375 | In this mode the watcher will always be scheduled to time out at the |
|
|
376 | next C<$at + N * $interval> time (for some integer N) and then repeat, |
|
|
377 | regardless of any time jumps. |
|
|
378 | |
|
|
379 | This can be used to create timers that do not drift with respect to system |
|
|
380 | time: |
|
|
381 | |
|
|
382 | my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; |
|
|
383 | |
|
|
384 | That doesn't mean there will always be 3600 seconds in between triggers, |
|
|
385 | but only that the the clalback will be called when the system time shows a |
|
|
386 | full hour (UTC). |
176 | |
387 | |
177 | Another way to think about it (for the mathematically inclined) is that |
388 | Another way to think about it (for the mathematically inclined) is that |
178 | C<timer_abs> will try to tun the callback at the next possible time where |
389 | EV::periodic will try to run the callback in this mode at the next |
179 | C<$time = $at (mod $interval)>, regardless of any time jumps. |
390 | possible time where C<$time = $at (mod $interval)>, regardless of any time |
|
|
391 | jumps. |
180 | |
392 | |
181 | The C<timer_abs_ns> variant doesn't add/start the newly created watcher. |
393 | =item * manual reschedule mode ($reschedule_cb = coderef) |
182 | |
394 | |
183 | =item my $w = EV::signal $signum, $callback |
395 | In this mode $interval and $at are both being ignored. Instead, each |
|
|
396 | time the periodic watcher gets scheduled, the reschedule callback |
|
|
397 | ($reschedule_cb) will be called with the watcher as first, and the current |
|
|
398 | time as second argument. |
184 | |
399 | |
185 | =item my $w = EV::signal_ns $signum, $callback |
400 | I<This callback MUST NOT stop or destroy this or any other periodic |
|
|
401 | watcher, ever>. If you need to stop it, return 1e30 and stop it |
|
|
402 | afterwards. |
186 | |
403 | |
187 | Call the callback when signal $signum is received. |
404 | It must return the next time to trigger, based on the passed time value |
|
|
405 | (that is, the lowest time value larger than to the second argument). It |
|
|
406 | will usually be called just before the callback will be triggered, but |
|
|
407 | might be called at other times, too. |
188 | |
408 | |
189 | The C<signal_ns> variant doesn't add/start the newly created watcher. |
409 | This can be used to create very complex timers, such as a timer that |
|
|
410 | triggers on each midnight, local time (actually 24 hours after the last |
|
|
411 | midnight, to keep the example simple. If you know a way to do it correctly |
|
|
412 | in about the same space (without requiring elaborate modules), drop me a |
|
|
413 | note :): |
|
|
414 | |
|
|
415 | my $daily = EV::periodic 0, 0, sub { |
|
|
416 | my ($w, $now) = @_; |
|
|
417 | |
|
|
418 | use Time::Local (); |
|
|
419 | my (undef, undef, undef, $d, $m, $y) = localtime $now; |
|
|
420 | 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y |
|
|
421 | }, sub { |
|
|
422 | print "it's midnight or likely shortly after, now\n"; |
|
|
423 | }; |
190 | |
424 | |
191 | =back |
425 | =back |
192 | |
426 | |
193 | =head1 THE EV::Event CLASS |
427 | The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
194 | |
428 | |
195 | All EV functions creating an event watcher (designated by C<my $w => |
429 | =item $w->set ($at, $interval, $reschedule_cb) |
196 | above) support the following methods on the returned watcher object: |
|
|
197 | |
430 | |
198 | =over 4 |
431 | Reconfigures the watcher, see the constructor above for details. Can be at |
|
|
432 | any time. |
199 | |
433 | |
200 | =item $w->add ($timeout) |
434 | =item $w->again |
201 | |
435 | |
202 | Stops and (re-)starts the event watcher, setting the optional timeout to |
436 | Simply stops and starts the watcher again. |
203 | the given value, or clearing the timeout if none is given. |
|
|
204 | |
437 | |
205 | =item $w->start |
|
|
206 | |
438 | |
207 | Stops and (re-)starts the event watcher without touching the timeout. |
439 | =item $w = EV::signal $signal, $callback |
208 | |
440 | |
209 | =item $w->del |
441 | =item $w = EV::signal_ns $signal, $callback |
210 | |
442 | |
211 | =item $w->stop |
443 | Call the callback when $signal is received (the signal can be specified |
|
|
444 | by number or by name, just as with kill or %SIG). |
212 | |
445 | |
213 | Stop the event watcher if it was started. |
446 | EV will grab the signal for the process (the kernel only allows one |
|
|
447 | component to receive a signal at a time) when you start a signal watcher, |
|
|
448 | and removes it again when you stop it. Perl does the same when you |
|
|
449 | add/remove callbacks to %SIG, so watch out. |
214 | |
450 | |
215 | =item $current_callback = $w->cb |
451 | You can have as many signal watchers per signal as you want. |
216 | |
452 | |
217 | =item $old_callback = $w->cb ($new_callback) |
453 | The C<signal_ns> variant doesn't start (activate) the newly created watcher. |
218 | |
454 | |
219 | Return the previously set callback and optionally set a new one. |
455 | =item $w->set ($signal) |
220 | |
456 | |
221 | =item $current_fh = $w->fh |
457 | Reconfigures the watcher, see the constructor above for details. Can be at |
|
|
458 | any time. |
222 | |
459 | |
223 | =item $old_fh = $w->fh ($new_fh) |
|
|
224 | |
|
|
225 | Returns the previously set filehandle and optionally set a new one (also |
|
|
226 | clears the EV::SIGNAL flag when setting a filehandle). |
|
|
227 | |
|
|
228 | =item $current_signal = $w->signal |
460 | =item $current_signum = $w->signal |
229 | |
461 | |
230 | =item $old_signal = $w->signal ($new_signal) |
462 | =item $old_signum = $w->signal ($new_signal) |
231 | |
463 | |
232 | Returns the previously set signal number and optionally set a new one (also sets |
464 | Returns the previously set signal (always as a number not name) and |
233 | the EV::SIGNAL flag when setting a signal). |
465 | optionally set a new one. |
234 | |
466 | |
235 | =item $current_eventmask = $w->events |
|
|
236 | |
467 | |
237 | =item $old_eventmask = $w->events ($new_eventmask) |
468 | =item $w = EV::child $pid, $callback |
238 | |
469 | |
|
|
470 | =item $w = EV::child_ns $pid, $callback |
|
|
471 | |
|
|
472 | Call the callback when a status change for pid C<$pid> (or any pid |
|
|
473 | if C<$pid> is 0) has been received. More precisely: when the process |
|
|
474 | receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all |
|
|
475 | changed/zombie children and call the callback. |
|
|
476 | |
|
|
477 | You can access both status and pid by using the C<rstatus> and C<rpid> |
|
|
478 | methods on the watcher object. |
|
|
479 | |
|
|
480 | You can have as many pid watchers per pid as you want. |
|
|
481 | |
|
|
482 | The C<child_ns> variant doesn't start (activate) the newly created watcher. |
|
|
483 | |
|
|
484 | =item $w->set ($pid) |
|
|
485 | |
|
|
486 | Reconfigures the watcher, see the constructor above for details. Can be at |
|
|
487 | any time. |
|
|
488 | |
|
|
489 | =item $current_pid = $w->pid |
|
|
490 | |
|
|
491 | =item $old_pid = $w->pid ($new_pid) |
|
|
492 | |
239 | Returns the previously set event mask and optionally set a new one. |
493 | Returns the previously set process id and optionally set a new one. |
240 | |
494 | |
241 | =item $w->timeout ($after, $repeat) |
495 | =item $exit_status = $w->rstatus |
242 | |
496 | |
243 | Resets the timeout (see C<EV::timer> for details). |
497 | Return the exit/wait status (as returned by waitpid, see the waitpid entry |
|
|
498 | in perlfunc). |
244 | |
499 | |
245 | =item $w->timeout_abs ($at, $interval) |
500 | =item $pid = $w->rpid |
246 | |
501 | |
247 | Resets the timeout (see C<EV::timer_abs> for details). |
502 | Return the pid of the awaited child (useful when you have installed a |
|
|
503 | watcher for all pids). |
248 | |
504 | |
249 | =item $w->priority_set ($priority) |
|
|
250 | |
505 | |
251 | Set the priority of the watcher to C<$priority> (0 <= $priority < $EV::NPRI). |
506 | =item $w = EV::idle $callback |
|
|
507 | |
|
|
508 | =item $w = EV::idle_ns $callback |
|
|
509 | |
|
|
510 | Call the callback when there are no pending io, timer/periodic, signal or |
|
|
511 | child events, i.e. when the process is idle. |
|
|
512 | |
|
|
513 | The process will not block as long as any idle watchers are active, and |
|
|
514 | they will be called repeatedly until stopped. |
|
|
515 | |
|
|
516 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
|
|
517 | |
|
|
518 | |
|
|
519 | =item $w = EV::prepare $callback |
|
|
520 | |
|
|
521 | =item $w = EV::prepare_ns $callback |
|
|
522 | |
|
|
523 | Call the callback just before the process would block. You can still |
|
|
524 | create/modify any watchers at this point. |
|
|
525 | |
|
|
526 | See the EV::check watcher, below, for explanations and an example. |
|
|
527 | |
|
|
528 | The C<prepare_ns> variant doesn't start (activate) the newly created watcher. |
|
|
529 | |
|
|
530 | |
|
|
531 | =item $w = EV::check $callback |
|
|
532 | |
|
|
533 | =item $w = EV::check_ns $callback |
|
|
534 | |
|
|
535 | Call the callback just after the process wakes up again (after it has |
|
|
536 | gathered events), but before any other callbacks have been invoked. |
|
|
537 | |
|
|
538 | This is used to integrate other event-based software into the EV |
|
|
539 | mainloop: You register a prepare callback and in there, you create io and |
|
|
540 | timer watchers as required by the other software. Here is a real-world |
|
|
541 | example of integrating Net::SNMP (with some details left out): |
|
|
542 | |
|
|
543 | our @snmp_watcher; |
|
|
544 | |
|
|
545 | our $snmp_prepare = EV::prepare sub { |
|
|
546 | # do nothing unless active |
|
|
547 | $dispatcher->{_event_queue_h} |
|
|
548 | or return; |
|
|
549 | |
|
|
550 | # make the dispatcher handle any outstanding stuff |
|
|
551 | ... not shown |
|
|
552 | |
|
|
553 | # create an IO watcher for each and every socket |
|
|
554 | @snmp_watcher = ( |
|
|
555 | (map { EV::io $_, EV::READ, sub { } } |
|
|
556 | keys %{ $dispatcher->{_descriptors} }), |
|
|
557 | |
|
|
558 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
|
|
559 | ? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0), |
|
|
560 | 0, sub { }, |
|
|
561 | ); |
|
|
562 | }; |
|
|
563 | |
|
|
564 | The callbacks are irrelevant (and are not even being called), the |
|
|
565 | only purpose of those watchers is to wake up the process as soon as |
|
|
566 | one of those events occurs (socket readable, or timer timed out). The |
|
|
567 | corresponding EV::check watcher will then clean up: |
|
|
568 | |
|
|
569 | our $snmp_check = EV::check sub { |
|
|
570 | # destroy all watchers |
|
|
571 | @snmp_watcher = (); |
|
|
572 | |
|
|
573 | # make the dispatcher handle any new stuff |
|
|
574 | ... not shown |
|
|
575 | }; |
|
|
576 | |
|
|
577 | The callbacks of the created watchers will not be called as the watchers |
|
|
578 | are destroyed before this cna happen (remember EV::check gets called |
|
|
579 | first). |
|
|
580 | |
|
|
581 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
252 | |
582 | |
253 | =back |
583 | =back |
254 | |
584 | |
255 | =head1 BUGS |
585 | =head1 THREADS |
256 | |
586 | |
257 | Lots. Libevent itself isn't well tested and rather buggy, and this module |
587 | Threads are not supported by this module in any way. Perl pseudo-threads |
258 | is quite new at the moment. |
588 | is evil stuff and must die. As soon as Perl gains real threads I will work |
|
|
589 | on thread support for it. |
259 | |
590 | |
260 | Please note that the epoll method is not, in general, reliable in programs |
591 | =head1 FORK |
261 | that use fork (even if no libveent calls are being made in the forked |
|
|
262 | process). If your program behaves erratically, try setting the environment |
|
|
263 | variable C<EVENT_NOEPOLL> first when running the program. |
|
|
264 | |
592 | |
265 | In general, if you fork, then you can only use the EV module in one of the |
593 | Most of the "improved" event delivering mechanisms of modern operating |
266 | children. |
594 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
|
|
595 | not supported and usually destructive). Libev makes it possible to work |
|
|
596 | around this by having a function that recreates the kernel state after |
|
|
597 | fork in the child. |
|
|
598 | |
|
|
599 | On non-win32 platforms, this module requires the pthread_atfork |
|
|
600 | functionality to do this automatically for you. This function is quite |
|
|
601 | buggy on most BSDs, though, so YMMV. The overhead for this is quite |
|
|
602 | negligible, because everything the function currently does is set a flag |
|
|
603 | that is checked only when the event loop gets used the next time, so when |
|
|
604 | you do fork but not use EV, the overhead is minimal. |
|
|
605 | |
|
|
606 | On win32, there is no notion of fork so all this doesn't apply, of course. |
267 | |
607 | |
268 | =cut |
608 | =cut |
269 | |
609 | |
270 | our $DIED = sub { |
610 | our $DIED = sub { |
271 | warn "EV: error in callback (ignoring): $@"; |
611 | warn "EV: error in callback (ignoring): $@"; |
272 | }; |
612 | }; |
273 | |
613 | |
274 | our $NPRI = 4; |
614 | default_loop |
275 | our $BASE = init; |
615 | or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; |
276 | priority_init $NPRI; |
|
|
277 | |
|
|
278 | push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"]; |
|
|
279 | |
616 | |
280 | 1; |
617 | 1; |
281 | |
618 | |
282 | =head1 SEE ALSO |
619 | =head1 SEE ALSO |
283 | |
620 | |
284 | L<EV::DNS>, L<event(3)>, L<event.h>, L<evdns.h>. |
621 | L<EV::DNS>. |
285 | L<EV::AnyEvent>. |
|
|
286 | |
622 | |
287 | =head1 AUTHOR |
623 | =head1 AUTHOR |
288 | |
624 | |
289 | Marc Lehmann <schmorp@schmorp.de> |
625 | Marc Lehmann <schmorp@schmorp.de> |
290 | http://home.schmorp.de/ |
626 | http://home.schmorp.de/ |