1 |
root |
1.1 |
=head1 NAME |
2 |
|
|
|
3 |
root |
1.20 |
EV - perl interface to libev, a high performance full-featured event loop |
4 |
root |
1.1 |
|
5 |
|
|
=head1 SYNOPSIS |
6 |
|
|
|
7 |
root |
1.11 |
use EV; |
8 |
|
|
|
9 |
root |
1.20 |
# TIMERS |
10 |
root |
1.11 |
|
11 |
|
|
my $w = EV::timer 2, 0, sub { |
12 |
|
|
warn "is called after 2s"; |
13 |
|
|
}; |
14 |
|
|
|
15 |
root |
1.35 |
my $w = EV::timer 2, 2, sub { |
16 |
|
|
warn "is called roughly every 2s (repeat = 2)"; |
17 |
root |
1.11 |
}; |
18 |
|
|
|
19 |
|
|
undef $w; # destroy event watcher again |
20 |
|
|
|
21 |
root |
1.30 |
my $w = EV::periodic 0, 60, 0, sub { |
22 |
root |
1.11 |
warn "is called every minute, on the minute, exactly"; |
23 |
|
|
}; |
24 |
|
|
|
25 |
|
|
# IO |
26 |
|
|
|
27 |
root |
1.20 |
my $w = EV::io *STDIN, EV::READ, sub { |
28 |
root |
1.35 |
my ($w, $revents) = @_; # all callbacks receive the watcher and event mask |
29 |
root |
1.20 |
warn "stdin is readable, you entered: ", <STDIN>; |
30 |
root |
1.11 |
}; |
31 |
|
|
|
32 |
|
|
# SIGNALS |
33 |
|
|
|
34 |
|
|
my $w = EV::signal 'QUIT', sub { |
35 |
|
|
warn "sigquit received\n"; |
36 |
|
|
}; |
37 |
|
|
|
38 |
root |
1.16 |
# CHILD/PID STATUS CHANGES |
39 |
|
|
|
40 |
|
|
my $w = EV::child 666, sub { |
41 |
root |
1.27 |
my ($w, $revents) = @_; |
42 |
|
|
my $status = $w->rstatus; |
43 |
root |
1.16 |
}; |
44 |
root |
1.11 |
|
45 |
|
|
# MAINLOOP |
46 |
root |
1.39 |
EV::loop; # loop until EV::unloop is called or all watchers stop |
47 |
root |
1.20 |
EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled |
48 |
|
|
EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block |
49 |
root |
1.2 |
|
50 |
root |
1.1 |
=head1 DESCRIPTION |
51 |
|
|
|
52 |
root |
1.16 |
This module provides an interface to libev |
53 |
root |
1.20 |
(L<http://software.schmorp.de/pkg/libev.html>). |
54 |
root |
1.1 |
|
55 |
|
|
=cut |
56 |
|
|
|
57 |
|
|
package EV; |
58 |
|
|
|
59 |
|
|
use strict; |
60 |
|
|
|
61 |
|
|
BEGIN { |
62 |
root |
1.44 |
our $VERSION = '1.2'; |
63 |
root |
1.1 |
use XSLoader; |
64 |
|
|
XSLoader::load "EV", $VERSION; |
65 |
|
|
} |
66 |
|
|
|
67 |
root |
1.18 |
@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 |
root |
1.17 |
@EV::Child::ISA = "EV::Watcher"; |
75 |
root |
1.15 |
|
76 |
root |
1.8 |
=head1 BASIC INTERFACE |
77 |
root |
1.1 |
|
78 |
|
|
=over 4 |
79 |
|
|
|
80 |
root |
1.8 |
=item $EV::DIED |
81 |
|
|
|
82 |
|
|
Must contain a reference to a function that is called when a callback |
83 |
|
|
throws an exception (with $@ containing thr error). The default prints an |
84 |
|
|
informative message and continues. |
85 |
|
|
|
86 |
|
|
If this callback throws an exception it will be silently ignored. |
87 |
|
|
|
88 |
root |
1.20 |
=item $time = EV::time |
89 |
|
|
|
90 |
|
|
Returns the current time in (fractional) seconds since the epoch. |
91 |
|
|
|
92 |
root |
1.2 |
=item $time = EV::now |
93 |
|
|
|
94 |
root |
1.20 |
Returns the time the last event loop iteration has been started. This |
95 |
|
|
is the time that (relative) timers are based on, and refering to it is |
96 |
|
|
usually faster then calling EV::time. |
97 |
|
|
|
98 |
root |
1.41 |
=item $method = EV::method |
99 |
root |
1.20 |
|
100 |
|
|
Returns an integer describing the backend used by libev (EV::METHOD_SELECT |
101 |
|
|
or EV::METHOD_EPOLL). |
102 |
|
|
|
103 |
|
|
=item EV::loop [$flags] |
104 |
root |
1.2 |
|
105 |
root |
1.20 |
Begin checking for events and calling callbacks. It returns when a |
106 |
root |
1.39 |
callback calls EV::unloop. |
107 |
root |
1.2 |
|
108 |
root |
1.20 |
The $flags argument can be one of the following: |
109 |
root |
1.2 |
|
110 |
root |
1.20 |
0 as above |
111 |
|
|
EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
112 |
|
|
EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
113 |
root |
1.2 |
|
114 |
root |
1.39 |
=item EV::unloop [$how] |
115 |
root |
1.2 |
|
116 |
root |
1.39 |
When called with no arguments or an argument of EV::UNLOOP_ONE, makes the |
117 |
|
|
innermost call to EV::loop return. |
118 |
root |
1.2 |
|
119 |
root |
1.39 |
When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as |
120 |
root |
1.20 |
fast as possible. |
121 |
root |
1.2 |
|
122 |
root |
1.47 |
=item EV::once $fh_or_undef, $events, $timeout, $cb->($events) |
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 |
root |
1.20 |
=back |
146 |
|
|
|
147 |
|
|
=head2 WATCHER |
148 |
root |
1.2 |
|
149 |
root |
1.20 |
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 |
root |
1.2 |
|
158 |
root |
1.20 |
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 |
root |
1.23 |
object is destroyed, so you I<need> to keep the watcher objects returned by |
176 |
root |
1.20 |
the constructors. |
177 |
|
|
|
178 |
root |
1.23 |
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 |
root |
1.20 |
=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 |
root |
1.2 |
|
193 |
root |
1.20 |
=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 |
root |
1.2 |
|
201 |
root |
1.20 |
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 |
root |
1.2 |
|
205 |
root |
1.20 |
=item $bool = $w->is_active |
206 |
root |
1.2 |
|
207 |
root |
1.20 |
Returns true if the watcher is active, false otherwise. |
208 |
|
|
|
209 |
root |
1.30 |
=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 |
root |
1.20 |
=item $current_cb = $w->cb |
222 |
|
|
|
223 |
|
|
=item $old_cb = $w->cb ($new_cb) |
224 |
|
|
|
225 |
root |
1.23 |
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 |
root |
1.24 |
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 |
root |
1.23 |
normalised to the nearest valid priority. |
237 |
|
|
|
238 |
|
|
The default priority of any newly-created weatcher is 0. |
239 |
root |
1.20 |
|
240 |
|
|
=item $w->trigger ($revents) |
241 |
|
|
|
242 |
|
|
Call the callback *now* with the given event mask. |
243 |
|
|
|
244 |
|
|
|
245 |
|
|
=item $w = EV::io $fileno_or_fh, $eventmask, $callback |
246 |
root |
1.2 |
|
247 |
root |
1.20 |
=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
248 |
root |
1.7 |
|
249 |
root |
1.20 |
As long as the returned watcher object is alive, call the C<$callback> |
250 |
|
|
when the events specified in C<$eventmask>. |
251 |
root |
1.2 |
|
252 |
root |
1.20 |
The $eventmask can be one or more of these constants ORed together: |
253 |
root |
1.2 |
|
254 |
|
|
EV::READ wait until read() wouldn't block anymore |
255 |
|
|
EV::WRITE wait until write() wouldn't block anymore |
256 |
root |
1.7 |
|
257 |
root |
1.20 |
The C<io_ns> variant doesn't start (activate) the newly created watcher. |
258 |
root |
1.2 |
|
259 |
root |
1.20 |
=item $w->set ($fileno_or_fh, $eventmask) |
260 |
root |
1.10 |
|
261 |
root |
1.20 |
Reconfigures the watcher, see the constructor above for details. Can be |
262 |
|
|
called at any time. |
263 |
root |
1.10 |
|
264 |
root |
1.20 |
=item $current_fh = $w->fh |
265 |
|
|
|
266 |
|
|
=item $old_fh = $w->fh ($new_fh) |
267 |
|
|
|
268 |
|
|
Returns the previously set filehandle and optionally set a new one. |
269 |
root |
1.10 |
|
270 |
root |
1.20 |
=item $current_eventmask = $w->events |
271 |
|
|
|
272 |
|
|
=item $old_eventmask = $w->events ($new_eventmask) |
273 |
root |
1.10 |
|
274 |
root |
1.20 |
Returns the previously set event mask and optionally set a new one. |
275 |
root |
1.10 |
|
276 |
|
|
|
277 |
root |
1.20 |
=item $w = EV::timer $after, $repeat, $callback |
278 |
root |
1.2 |
|
279 |
root |
1.20 |
=item $w = EV::timer_ns $after, $repeat, $callback |
280 |
root |
1.2 |
|
281 |
root |
1.20 |
Calls the callback after C<$after> seconds. If C<$repeat> is non-zero, |
282 |
|
|
the timer will be restarted (with the $repeat value as $after) after the |
283 |
|
|
callback returns. |
284 |
root |
1.2 |
|
285 |
root |
1.20 |
This means that the callback would be called roughly after C<$after> |
286 |
root |
1.39 |
seconds, and then every C<$repeat> seconds. The timer does his best not |
287 |
|
|
to drift, but it will not invoke the timer more often then once per event |
288 |
|
|
loop iteration, and might drift in other cases. If that isn't acceptable, |
289 |
|
|
look at EV::periodic, which can provide long-term stable timers. |
290 |
root |
1.2 |
|
291 |
root |
1.39 |
The timer is based on a monotonic clock, that is, if somebody is sitting |
292 |
root |
1.20 |
in front of the machine while the timer is running and changes the system |
293 |
|
|
clock, the timer will nevertheless run (roughly) the same time. |
294 |
root |
1.2 |
|
295 |
root |
1.20 |
The C<timer_ns> variant doesn't start (activate) the newly created watcher. |
296 |
|
|
|
297 |
|
|
=item $w->set ($after, $repeat) |
298 |
|
|
|
299 |
|
|
Reconfigures the watcher, see the constructor above for details. Can be at |
300 |
|
|
any time. |
301 |
|
|
|
302 |
|
|
=item $w->again |
303 |
|
|
|
304 |
|
|
Similar to the C<start> method, but has special semantics for repeating timers: |
305 |
|
|
|
306 |
root |
1.39 |
If the timer is active and non-repeating, it will be stopped. |
307 |
|
|
|
308 |
root |
1.20 |
If the timer is active and repeating, reset the timeout to occur |
309 |
|
|
C<$repeat> seconds after now. |
310 |
|
|
|
311 |
root |
1.39 |
If the timer is inactive and repeating, start it using the repeat value. |
312 |
root |
1.20 |
|
313 |
|
|
Otherwise do nothing. |
314 |
|
|
|
315 |
|
|
This behaviour is useful when you have a timeout for some IO |
316 |
|
|
operation. You create a timer object with the same value for C<$after> and |
317 |
|
|
C<$repeat>, and then, in the read/write watcher, run the C<again> method |
318 |
|
|
on the timeout. |
319 |
|
|
|
320 |
|
|
|
321 |
root |
1.30 |
=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
322 |
root |
1.20 |
|
323 |
root |
1.30 |
=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
324 |
|
|
|
325 |
|
|
Similar to EV::timer, but is not based on relative timeouts but on |
326 |
|
|
absolute times. Apart from creating "simple" timers that trigger "at" the |
327 |
|
|
specified time, it can also be used for non-drifting absolute timers and |
328 |
|
|
more complex, cron-like, setups that are not adversely affected by time |
329 |
|
|
jumps (i.e. when the system clock is changed by explicit date -s or other |
330 |
|
|
means such as ntpd). It is also the most complex watcher type in EV. |
331 |
|
|
|
332 |
|
|
It has three distinct "modes": |
333 |
|
|
|
334 |
|
|
=over 4 |
335 |
root |
1.2 |
|
336 |
root |
1.30 |
=item * absolute timer ($interval = $reschedule_cb = 0) |
337 |
root |
1.2 |
|
338 |
root |
1.30 |
This time simply fires at the wallclock time C<$at> and doesn't repeat. It |
339 |
|
|
will not adjust when a time jump occurs, that is, if it is to be run |
340 |
|
|
at January 1st 2011 then it will run when the system time reaches or |
341 |
|
|
surpasses this time. |
342 |
root |
1.2 |
|
343 |
root |
1.30 |
=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) |
344 |
root |
1.2 |
|
345 |
root |
1.30 |
In this mode the watcher will always be scheduled to time out at the |
346 |
|
|
next C<$at + N * $interval> time (for some integer N) and then repeat, |
347 |
|
|
regardless of any time jumps. |
348 |
|
|
|
349 |
|
|
This can be used to create timers that do not drift with respect to system |
350 |
|
|
time: |
351 |
|
|
|
352 |
|
|
my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; |
353 |
|
|
|
354 |
|
|
That doesn't mean there will always be 3600 seconds in between triggers, |
355 |
|
|
but only that the the clalback will be called when the system time shows a |
356 |
|
|
full hour (UTC). |
357 |
root |
1.2 |
|
358 |
root |
1.7 |
Another way to think about it (for the mathematically inclined) is that |
359 |
root |
1.30 |
EV::periodic will try to run the callback in this mode at the next |
360 |
|
|
possible time where C<$time = $at (mod $interval)>, regardless of any time |
361 |
|
|
jumps. |
362 |
|
|
|
363 |
|
|
=item * manual reschedule mode ($reschedule_cb = coderef) |
364 |
|
|
|
365 |
root |
1.37 |
In this mode $interval and $at are both being ignored. Instead, each |
366 |
|
|
time the periodic watcher gets scheduled, the reschedule callback |
367 |
|
|
($reschedule_cb) will be called with the watcher as first, and the current |
368 |
|
|
time as second argument. |
369 |
root |
1.30 |
|
370 |
root |
1.31 |
I<This callback MUST NOT stop or destroy this or any other periodic |
371 |
|
|
watcher, ever>. If you need to stop it, return 1e30 and stop it |
372 |
|
|
afterwards. |
373 |
root |
1.30 |
|
374 |
|
|
It must return the next time to trigger, based on the passed time value |
375 |
|
|
(that is, the lowest time value larger than to the second argument). It |
376 |
|
|
will usually be called just before the callback will be triggered, but |
377 |
|
|
might be called at other times, too. |
378 |
|
|
|
379 |
|
|
This can be used to create very complex timers, such as a timer that |
380 |
|
|
triggers on each midnight, local time (actually 24 hours after the last |
381 |
|
|
midnight, to keep the example simple. If you know a way to do it correctly |
382 |
|
|
in about the same space (without requiring elaborate modules), drop me a |
383 |
|
|
note :): |
384 |
|
|
|
385 |
|
|
my $daily = EV::periodic 0, 0, sub { |
386 |
|
|
my ($w, $now) = @_; |
387 |
|
|
|
388 |
|
|
use Time::Local (); |
389 |
|
|
my (undef, undef, undef, $d, $m, $y) = localtime $now; |
390 |
|
|
86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y |
391 |
|
|
}, sub { |
392 |
|
|
print "it's midnight or likely shortly after, now\n"; |
393 |
|
|
}; |
394 |
root |
1.7 |
|
395 |
root |
1.30 |
=back |
396 |
root |
1.20 |
|
397 |
|
|
The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
398 |
root |
1.2 |
|
399 |
root |
1.30 |
=item $w->set ($at, $interval, $reschedule_cb) |
400 |
root |
1.11 |
|
401 |
root |
1.20 |
Reconfigures the watcher, see the constructor above for details. Can be at |
402 |
|
|
any time. |
403 |
|
|
|
404 |
root |
1.30 |
=item $w->again |
405 |
|
|
|
406 |
|
|
Simply stops and starts the watcher again. |
407 |
|
|
|
408 |
root |
1.20 |
|
409 |
|
|
=item $w = EV::signal $signal, $callback |
410 |
|
|
|
411 |
|
|
=item $w = EV::signal_ns $signal, $callback |
412 |
root |
1.11 |
|
413 |
|
|
Call the callback when $signal is received (the signal can be specified |
414 |
root |
1.20 |
by number or by name, just as with kill or %SIG). |
415 |
root |
1.2 |
|
416 |
root |
1.11 |
EV will grab the signal for the process (the kernel only allows one |
417 |
root |
1.20 |
component to receive a signal at a time) when you start a signal watcher, |
418 |
|
|
and removes it again when you stop it. Perl does the same when you |
419 |
|
|
add/remove callbacks to %SIG, so watch out. |
420 |
|
|
|
421 |
|
|
You can have as many signal watchers per signal as you want. |
422 |
root |
1.2 |
|
423 |
root |
1.20 |
The C<signal_ns> variant doesn't start (activate) the newly created watcher. |
424 |
root |
1.2 |
|
425 |
root |
1.20 |
=item $w->set ($signal) |
426 |
root |
1.2 |
|
427 |
root |
1.20 |
Reconfigures the watcher, see the constructor above for details. Can be at |
428 |
|
|
any time. |
429 |
|
|
|
430 |
root |
1.22 |
=item $current_signum = $w->signal |
431 |
|
|
|
432 |
|
|
=item $old_signum = $w->signal ($new_signal) |
433 |
|
|
|
434 |
|
|
Returns the previously set signal (always as a number not name) and |
435 |
|
|
optionally set a new one. |
436 |
|
|
|
437 |
root |
1.20 |
|
438 |
|
|
=item $w = EV::child $pid, $callback |
439 |
|
|
|
440 |
|
|
=item $w = EV::child_ns $pid, $callback |
441 |
|
|
|
442 |
|
|
Call the callback when a status change for pid C<$pid> (or any pid |
443 |
|
|
if C<$pid> is 0) has been received. More precisely: when the process |
444 |
|
|
receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all |
445 |
|
|
changed/zombie children and call the callback. |
446 |
|
|
|
447 |
root |
1.27 |
You can access both status and pid by using the C<rstatus> and C<rpid> |
448 |
|
|
methods on the watcher object. |
449 |
root |
1.20 |
|
450 |
|
|
You can have as many pid watchers per pid as you want. |
451 |
|
|
|
452 |
|
|
The C<child_ns> variant doesn't start (activate) the newly created watcher. |
453 |
|
|
|
454 |
|
|
=item $w->set ($pid) |
455 |
root |
1.1 |
|
456 |
root |
1.20 |
Reconfigures the watcher, see the constructor above for details. Can be at |
457 |
|
|
any time. |
458 |
root |
1.2 |
|
459 |
root |
1.22 |
=item $current_pid = $w->pid |
460 |
|
|
|
461 |
|
|
=item $old_pid = $w->pid ($new_pid) |
462 |
|
|
|
463 |
|
|
Returns the previously set process id and optionally set a new one. |
464 |
|
|
|
465 |
root |
1.27 |
=item $exit_status = $w->rstatus |
466 |
|
|
|
467 |
|
|
Return the exit/wait status (as returned by waitpid, see the waitpid entry |
468 |
|
|
in perlfunc). |
469 |
|
|
|
470 |
|
|
=item $pid = $w->rpid |
471 |
|
|
|
472 |
|
|
Return the pid of the awaited child (useful when you have installed a |
473 |
|
|
watcher for all pids). |
474 |
|
|
|
475 |
root |
1.2 |
|
476 |
root |
1.20 |
=item $w = EV::idle $callback |
477 |
root |
1.2 |
|
478 |
root |
1.20 |
=item $w = EV::idle_ns $callback |
479 |
root |
1.2 |
|
480 |
root |
1.20 |
Call the callback when there are no pending io, timer/periodic, signal or |
481 |
|
|
child events, i.e. when the process is idle. |
482 |
root |
1.2 |
|
483 |
root |
1.20 |
The process will not block as long as any idle watchers are active, and |
484 |
|
|
they will be called repeatedly until stopped. |
485 |
root |
1.2 |
|
486 |
root |
1.20 |
The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
487 |
root |
1.2 |
|
488 |
|
|
|
489 |
root |
1.20 |
=item $w = EV::prepare $callback |
490 |
root |
1.1 |
|
491 |
root |
1.20 |
=item $w = EV::prepare_ns $callback |
492 |
root |
1.1 |
|
493 |
root |
1.20 |
Call the callback just before the process would block. You can still |
494 |
|
|
create/modify any watchers at this point. |
495 |
root |
1.1 |
|
496 |
root |
1.20 |
See the EV::check watcher, below, for explanations and an example. |
497 |
root |
1.2 |
|
498 |
root |
1.20 |
The C<prepare_ns> variant doesn't start (activate) the newly created watcher. |
499 |
root |
1.2 |
|
500 |
|
|
|
501 |
root |
1.20 |
=item $w = EV::check $callback |
502 |
root |
1.2 |
|
503 |
root |
1.20 |
=item $w = EV::check_ns $callback |
504 |
root |
1.10 |
|
505 |
root |
1.20 |
Call the callback just after the process wakes up again (after it has |
506 |
|
|
gathered events), but before any other callbacks have been invoked. |
507 |
root |
1.10 |
|
508 |
root |
1.20 |
This is used to integrate other event-based software into the EV |
509 |
|
|
mainloop: You register a prepare callback and in there, you create io and |
510 |
|
|
timer watchers as required by the other software. Here is a real-world |
511 |
|
|
example of integrating Net::SNMP (with some details left out): |
512 |
root |
1.10 |
|
513 |
root |
1.20 |
our @snmp_watcher; |
514 |
root |
1.2 |
|
515 |
root |
1.20 |
our $snmp_prepare = EV::prepare sub { |
516 |
|
|
# do nothing unless active |
517 |
|
|
$dispatcher->{_event_queue_h} |
518 |
|
|
or return; |
519 |
root |
1.2 |
|
520 |
root |
1.20 |
# make the dispatcher handle any outstanding stuff |
521 |
root |
1.45 |
... not shown |
522 |
root |
1.2 |
|
523 |
root |
1.20 |
# create an IO watcher for each and every socket |
524 |
|
|
@snmp_watcher = ( |
525 |
|
|
(map { EV::io $_, EV::READ, sub { } } |
526 |
|
|
keys %{ $dispatcher->{_descriptors} }), |
527 |
root |
1.45 |
|
528 |
|
|
EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
529 |
|
|
? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0), |
530 |
|
|
0, sub { }, |
531 |
root |
1.20 |
); |
532 |
|
|
}; |
533 |
root |
1.2 |
|
534 |
root |
1.45 |
The callbacks are irrelevant (and are not even being called), the |
535 |
|
|
only purpose of those watchers is to wake up the process as soon as |
536 |
|
|
one of those events occurs (socket readable, or timer timed out). The |
537 |
|
|
corresponding EV::check watcher will then clean up: |
538 |
root |
1.2 |
|
539 |
root |
1.20 |
our $snmp_check = EV::check sub { |
540 |
|
|
# destroy all watchers |
541 |
|
|
@snmp_watcher = (); |
542 |
root |
1.2 |
|
543 |
root |
1.20 |
# make the dispatcher handle any new stuff |
544 |
root |
1.45 |
... not shown |
545 |
root |
1.20 |
}; |
546 |
root |
1.2 |
|
547 |
root |
1.20 |
The callbacks of the created watchers will not be called as the watchers |
548 |
|
|
are destroyed before this cna happen (remember EV::check gets called |
549 |
|
|
first). |
550 |
root |
1.2 |
|
551 |
root |
1.20 |
The C<check_ns> variant doesn't start (activate) the newly created watcher. |
552 |
root |
1.1 |
|
553 |
|
|
=back |
554 |
|
|
|
555 |
root |
1.13 |
=head1 THREADS |
556 |
|
|
|
557 |
root |
1.45 |
Threads are not supported by this module in any way. Perl pseudo-threads |
558 |
root |
1.46 |
is evil stuff and must die. As soon as Perl gains real threads I will work |
559 |
|
|
on thread support for it. |
560 |
|
|
|
561 |
|
|
=head1 FORK |
562 |
|
|
|
563 |
|
|
Most of the "improved" event delivering mechanisms of modern operating |
564 |
|
|
systems have quite a few problems with fork(2) (to put it bluntly: it is |
565 |
|
|
not supported and usually destructive). Libev makes it possible to work |
566 |
|
|
around this by having a function that recreates the kernel state after |
567 |
|
|
fork in the child. |
568 |
|
|
|
569 |
|
|
On non-win32 platforms, this module requires the pthread_atfork |
570 |
|
|
functionality to do this automatically for you. This function is quite |
571 |
|
|
buggy on most BSDs, though, so YMMV. The overhead for this is quite |
572 |
|
|
negligible, because everything the function currently does is set a flag |
573 |
|
|
that is checked only when the event loop gets used the next time, so when |
574 |
|
|
you do fork but not use EV, the overhead is minimal. |
575 |
|
|
|
576 |
|
|
On win32, there is no notion of fork so all this doesn't apply, of course. |
577 |
root |
1.13 |
|
578 |
root |
1.1 |
=cut |
579 |
|
|
|
580 |
root |
1.8 |
our $DIED = sub { |
581 |
|
|
warn "EV: error in callback (ignoring): $@"; |
582 |
|
|
}; |
583 |
|
|
|
584 |
root |
1.28 |
default_loop |
585 |
root |
1.26 |
or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; |
586 |
root |
1.1 |
|
587 |
|
|
1; |
588 |
|
|
|
589 |
root |
1.3 |
=head1 SEE ALSO |
590 |
|
|
|
591 |
root |
1.40 |
L<EV::DNS>. |
592 |
root |
1.3 |
|
593 |
root |
1.1 |
=head1 AUTHOR |
594 |
|
|
|
595 |
|
|
Marc Lehmann <schmorp@schmorp.de> |
596 |
|
|
http://home.schmorp.de/ |
597 |
|
|
|
598 |
|
|
=cut |
599 |
|
|
|