… | |
… | |
38 | |
38 | |
39 | my $w = EV::child 666, sub { |
39 | my $w = EV::child 666, sub { |
40 | my ($w, $revents) = @_; |
40 | my ($w, $revents) = @_; |
41 | my $status = $w->rstatus; |
41 | my $status = $w->rstatus; |
42 | }; |
42 | }; |
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43 | |
|
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44 | # STAT CHANGES |
|
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45 | my $w = EV::stat "/etc/passwd", 10, sub { |
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46 | my ($w, $revents) = @_; |
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47 | warn $w->path, " has changed somehow.\n"; |
|
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48 | }; |
43 | |
49 | |
44 | # MAINLOOP |
50 | # MAINLOOP |
45 | EV::loop; # loop until EV::loop_done is called or all watchers stop |
51 | EV::loop; # loop until EV::unloop is called or all watchers stop |
46 | EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled |
52 | EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled |
47 | EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block |
53 | EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block |
48 | |
54 | |
49 | DESCRIPTION |
55 | DESCRIPTION |
50 | This module provides an interface to libev |
56 | This module provides an interface to libev |
51 | (<http://software.schmorp.de/pkg/libev.html>). |
57 | (<http://software.schmorp.de/pkg/libev.html>). While the documentation |
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58 | below is comprehensive, one might also consult the documentation of |
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59 | libev itself (<http://cvs.schmorp.de/libev/ev.html>) for more subtle |
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60 | details on watcher semantics or some discussion on the available |
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61 | backends, or how to force a specific backend with "LIBEV_FLAGS". |
52 | |
62 | |
53 | BASIC INTERFACE |
63 | BASIC INTERFACE |
54 | $EV::DIED |
64 | $EV::DIED |
55 | Must contain a reference to a function that is called when a |
65 | Must contain a reference to a function that is called when a |
56 | callback throws an exception (with $@ containing thr error). The |
66 | callback throws an exception (with $@ containing thr error). The |
… | |
… | |
64 | $time = EV::now |
74 | $time = EV::now |
65 | Returns the time the last event loop iteration has been started. |
75 | Returns the time the last event loop iteration has been started. |
66 | This is the time that (relative) timers are based on, and refering |
76 | This is the time that (relative) timers are based on, and refering |
67 | to it is usually faster then calling EV::time. |
77 | to it is usually faster then calling EV::time. |
68 | |
78 | |
69 | $method = EV::ev_method |
79 | $method = EV::method |
70 | Returns an integer describing the backend used by libev |
80 | Returns an integer describing the backend used by libev |
71 | (EV::METHOD_SELECT or EV::METHOD_EPOLL). |
81 | (EV::METHOD_SELECT or EV::METHOD_EPOLL). |
72 | |
82 | |
73 | EV::loop [$flags] |
83 | EV::loop [$flags] |
74 | Begin checking for events and calling callbacks. It returns when a |
84 | Begin checking for events and calling callbacks. It returns when a |
75 | callback calls EV::loop_done. |
85 | callback calls EV::unloop. |
76 | |
86 | |
77 | The $flags argument can be one of the following: |
87 | The $flags argument can be one of the following: |
78 | |
88 | |
79 | 0 as above |
89 | 0 as above |
80 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
90 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
81 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
91 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
82 | |
92 | |
83 | EV::loop_done [$how] |
93 | EV::unloop [$how] |
84 | When called with no arguments or an argument of 1, makes the |
94 | When called with no arguments or an argument of EV::UNLOOP_ONE, |
85 | innermost call to EV::loop return. |
95 | makes the innermost call to EV::loop return. |
86 | |
96 | |
87 | When called with an agrument of 2, all calls to EV::loop will return |
97 | When called with an argument of EV::UNLOOP_ALL, all calls to |
88 | as fast as possible. |
98 | EV::loop will return as fast as possible. |
89 | |
99 | |
90 | WATCHER |
100 | EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
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101 | This function rolls together an I/O and a timer watcher for a single |
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102 | one-shot event without the need for managing a watcher object. |
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103 | |
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104 | If $fh_or_undef is a filehandle or file descriptor, then $events |
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105 | must be a bitset containing either "EV::READ", "EV::WRITE" or |
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106 | "EV::READ | EV::WRITE", indicating the type of I/O event you want to |
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107 | wait for. If you do not want to wait for some I/O event, specify |
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108 | "undef" for $fh_or_undef and 0 for $events). |
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109 | |
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110 | If timeout is "undef" or negative, then there will be no timeout. |
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111 | Otherwise a EV::timer with this value will be started. |
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112 | |
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113 | When an error occurs or either the timeout or I/O watcher triggers, |
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114 | then the callback will be called with the received event set (in |
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115 | general you can expect it to be a combination of "EV:ERROR", |
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116 | "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). |
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117 | |
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118 | EV::once doesn't return anything: the watchers stay active till |
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119 | either of them triggers, then they will be stopped and freed, and |
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120 | the callback invoked. |
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121 | |
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122 | WATCHER OBJECTS |
91 | A watcher is an object that gets created to record your interest in some |
123 | A watcher is an object that gets created to record your interest in some |
92 | event. For instance, if you want to wait for STDIN to become readable, |
124 | event. For instance, if you want to wait for STDIN to become readable, |
93 | you would create an EV::io watcher for that: |
125 | you would create an EV::io watcher for that: |
94 | |
126 | |
95 | my $watcher = EV::io *STDIN, EV::READ, sub { |
127 | my $watcher = EV::io *STDIN, EV::READ, sub { |
… | |
… | |
119 | |
151 | |
120 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
152 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
121 | ->fh and so on) automatically stop and start it again if it is active, |
153 | ->fh and so on) automatically stop and start it again if it is active, |
122 | which means pending events get lost. |
154 | which means pending events get lost. |
123 | |
155 | |
124 | WATCHER TYPES |
156 | COMMON WATCHER METHODS |
125 | Now lets move to the existing watcher types and asociated methods. |
157 | This section lists methods common to all watchers. |
126 | |
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127 | The following methods are available for all watchers. Then followes a |
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128 | description of each watcher constructor (EV::io, EV::timer, |
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129 | EV::periodic, EV::signal, EV::child, EV::idle, EV::prepare and |
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130 | EV::check), followed by any type-specific methods (if any). |
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131 | |
158 | |
132 | $w->start |
159 | $w->start |
133 | Starts a watcher if it isn't active already. Does nothing to an |
160 | Starts a watcher if it isn't active already. Does nothing to an |
134 | already active watcher. By default, all watchers start out in the |
161 | already active watcher. By default, all watchers start out in the |
135 | active state (see the description of the "_ns" variants if you need |
162 | active state (see the description of the "_ns" variants if you need |
… | |
… | |
165 | Pending watchers with higher priority will be invoked first. The |
192 | Pending watchers with higher priority will be invoked first. The |
166 | valid range of priorities lies between EV::MAXPRI (default 2) and |
193 | valid range of priorities lies between EV::MAXPRI (default 2) and |
167 | EV::MINPRI (default -2). If the priority is outside this range it |
194 | EV::MINPRI (default -2). If the priority is outside this range it |
168 | will automatically be normalised to the nearest valid priority. |
195 | will automatically be normalised to the nearest valid priority. |
169 | |
196 | |
170 | The default priority of any newly-created weatcher is 0. |
197 | The default priority of any newly-created watcher is 0. |
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198 | |
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199 | Note that the priority semantics have not yet been fleshed out and |
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200 | are subject to almost certain change. |
171 | |
201 | |
172 | $w->trigger ($revents) |
202 | $w->trigger ($revents) |
173 | Call the callback *now* with the given event mask. |
203 | Call the callback *now* with the given event mask. |
174 | |
204 | |
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205 | $previous_state = $w->keepalive ($bool) |
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206 | Normally, "EV::loop" will return when there are no active watchers |
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207 | (which is a "deadlock" because no progress can be made anymore). |
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208 | This is convinient because it allows you to start your watchers (and |
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209 | your jobs), call "EV::loop" once and when it returns you know that |
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210 | all your jobs are finished (or they forgot to register some watchers |
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211 | for their task :). |
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212 | |
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213 | Sometimes, however, this gets in your way, for example when you the |
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214 | module that calls "EV::loop" (usually the main program) is not the |
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215 | same module as a long-living watcher (for example a DNS client |
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216 | module written by somebody else even). Then you might want any |
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217 | outstanding requests to be handled, but you would not want to keep |
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218 | "EV::loop" from returning just because you happen to have this |
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219 | long-running UDP port watcher. |
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220 | |
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221 | In this case you can clear the keepalive status, which means that |
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222 | even though your watcher is active, it won't keep "EV::loop" from |
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223 | returning. |
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224 | |
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225 | The initial value for keepalive is true (enabled), and you cna |
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226 | change it any time. |
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227 | |
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228 | Example: Register an IO watcher for some UDP socket but do not keep |
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229 | the event loop from running just because of that watcher. |
|
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230 | |
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231 | my $udp_socket = ... |
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232 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
|
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233 | $udp_watcher->keepalive (0); |
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234 | |
|
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235 | WATCHER TYPES |
|
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236 | Each of the following subsections describes a single watcher type. |
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237 | |
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238 | IO WATCHERS - is this file descriptor readable or writable? |
175 | $w = EV::io $fileno_or_fh, $eventmask, $callback |
239 | $w = EV::io $fileno_or_fh, $eventmask, $callback |
176 | $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
240 | $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
177 | As long as the returned watcher object is alive, call the $callback |
241 | As long as the returned watcher object is alive, call the $callback |
178 | when the events specified in $eventmask. |
242 | when at least one of events specified in $eventmask occurs. |
179 | |
243 | |
180 | The $eventmask can be one or more of these constants ORed together: |
244 | The $eventmask can be one or more of these constants ORed together: |
181 | |
245 | |
182 | EV::READ wait until read() wouldn't block anymore |
246 | EV::READ wait until read() wouldn't block anymore |
183 | EV::WRITE wait until write() wouldn't block anymore |
247 | EV::WRITE wait until write() wouldn't block anymore |
… | |
… | |
195 | |
259 | |
196 | $current_eventmask = $w->events |
260 | $current_eventmask = $w->events |
197 | $old_eventmask = $w->events ($new_eventmask) |
261 | $old_eventmask = $w->events ($new_eventmask) |
198 | Returns the previously set event mask and optionally set a new one. |
262 | Returns the previously set event mask and optionally set a new one. |
199 | |
263 | |
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264 | TIMER WATCHERS - relative and optionally repeating timeouts |
200 | $w = EV::timer $after, $repeat, $callback |
265 | $w = EV::timer $after, $repeat, $callback |
201 | $w = EV::timer_ns $after, $repeat, $callback |
266 | $w = EV::timer_ns $after, $repeat, $callback |
202 | Calls the callback after $after seconds. If $repeat is non-zero, the |
267 | Calls the callback after $after seconds (which may be fractional). |
203 | timer will be restarted (with the $repeat value as $after) after the |
268 | If $repeat is non-zero, the timer will be restarted (with the |
204 | callback returns. |
269 | $repeat value as $after) after the callback returns. |
205 | |
270 | |
206 | This means that the callback would be called roughly after $after |
271 | This means that the callback would be called roughly after $after |
207 | seconds, and then every $repeat seconds. "Roughly" because the time |
272 | seconds, and then every $repeat seconds. The timer does his best not |
208 | of callback processing is not taken into account, so the timer will |
273 | to drift, but it will not invoke the timer more often then once per |
209 | slowly drift. If that isn't acceptable, look at EV::periodic. |
274 | event loop iteration, and might drift in other cases. If that isn't |
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275 | acceptable, look at EV::periodic, which can provide long-term stable |
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276 | timers. |
210 | |
277 | |
211 | The timer is based on a monotonic clock, that is if somebody is |
278 | The timer is based on a monotonic clock, that is, if somebody is |
212 | sitting in front of the machine while the timer is running and |
279 | sitting in front of the machine while the timer is running and |
213 | changes the system clock, the timer will nevertheless run (roughly) |
280 | changes the system clock, the timer will nevertheless run (roughly) |
214 | the same time. |
281 | the same time. |
215 | |
282 | |
216 | The "timer_ns" variant doesn't start (activate) the newly created |
283 | The "timer_ns" variant doesn't start (activate) the newly created |
217 | watcher. |
284 | watcher. |
218 | |
285 | |
219 | $w->set ($after, $repeat) |
286 | $w->set ($after, $repeat) |
220 | Reconfigures the watcher, see the constructor above for details. Can |
287 | Reconfigures the watcher, see the constructor above for details. Can |
221 | be at any time. |
288 | be called at any time. |
222 | |
289 | |
223 | $w->again |
290 | $w->again |
224 | Similar to the "start" method, but has special semantics for |
291 | Similar to the "start" method, but has special semantics for |
225 | repeating timers: |
292 | repeating timers: |
226 | |
293 | |
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294 | If the timer is active and non-repeating, it will be stopped. |
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295 | |
227 | If the timer is active and repeating, reset the timeout to occur |
296 | If the timer is active and repeating, reset the timeout to occur |
228 | $repeat seconds after now. |
297 | $repeat seconds after now. |
229 | |
298 | |
230 | If the timer is active and non-repeating, it will be stopped. |
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231 | |
|
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232 | If the timer is in active and repeating, start it. |
299 | If the timer is inactive and repeating, start it using the repeat |
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300 | value. |
233 | |
301 | |
234 | Otherwise do nothing. |
302 | Otherwise do nothing. |
235 | |
303 | |
236 | This behaviour is useful when you have a timeout for some IO |
304 | This behaviour is useful when you have a timeout for some IO |
237 | operation. You create a timer object with the same value for $after |
305 | operation. You create a timer object with the same value for $after |
238 | and $repeat, and then, in the read/write watcher, run the "again" |
306 | and $repeat, and then, in the read/write watcher, run the "again" |
239 | method on the timeout. |
307 | method on the timeout. |
240 | |
308 | |
|
|
309 | PERIODIC WATCHERS - to cron or not to cron? |
241 | $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
310 | $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
242 | $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
311 | $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
243 | Similar to EV::timer, but is not based on relative timeouts but on |
312 | Similar to EV::timer, but is not based on relative timeouts but on |
244 | absolute times. Apart from creating "simple" timers that trigger |
313 | absolute times. Apart from creating "simple" timers that trigger |
245 | "at" the specified time, it can also be used for non-drifting |
314 | "at" the specified time, it can also be used for non-drifting |
… | |
… | |
275 | at the next possible time where "$time = $at (mod $interval)", |
344 | at the next possible time where "$time = $at (mod $interval)", |
276 | regardless of any time jumps. |
345 | regardless of any time jumps. |
277 | |
346 | |
278 | * manual reschedule mode ($reschedule_cb = coderef) |
347 | * manual reschedule mode ($reschedule_cb = coderef) |
279 | In this mode $interval and $at are both being ignored. Instead, |
348 | In this mode $interval and $at are both being ignored. Instead, |
280 | each time the periodic watcher gets scheduled, the first |
349 | each time the periodic watcher gets scheduled, the reschedule |
281 | callback ($reschedule_cb) will be called with the watcher as |
350 | callback ($reschedule_cb) will be called with the watcher as |
282 | first, and the current time as second argument. |
351 | first, and the current time as second argument. |
283 | |
352 | |
284 | *This callback MUST NOT stop or destroy this or any other |
353 | *This callback MUST NOT stop or destroy this or any other |
285 | periodic watcher, ever*. If you need to stop it, return 1e30 and |
354 | periodic watcher, ever*. If you need to stop it, return 1e30 and |
… | |
… | |
310 | The "periodic_ns" variant doesn't start (activate) the newly created |
379 | The "periodic_ns" variant doesn't start (activate) the newly created |
311 | watcher. |
380 | watcher. |
312 | |
381 | |
313 | $w->set ($at, $interval, $reschedule_cb) |
382 | $w->set ($at, $interval, $reschedule_cb) |
314 | Reconfigures the watcher, see the constructor above for details. Can |
383 | Reconfigures the watcher, see the constructor above for details. Can |
315 | be at any time. |
384 | be called at any time. |
316 | |
385 | |
317 | $w->again |
386 | $w->again |
318 | Simply stops and starts the watcher again. |
387 | Simply stops and starts the watcher again. |
319 | |
388 | |
|
|
389 | SIGNAL WATCHERS - signal me when a signal gets signalled! |
320 | $w = EV::signal $signal, $callback |
390 | $w = EV::signal $signal, $callback |
321 | $w = EV::signal_ns $signal, $callback |
391 | $w = EV::signal_ns $signal, $callback |
322 | Call the callback when $signal is received (the signal can be |
392 | Call the callback when $signal is received (the signal can be |
323 | specified by number or by name, just as with kill or %SIG). |
393 | specified by number or by name, just as with "kill" or %SIG). |
324 | |
394 | |
325 | EV will grab the signal for the process (the kernel only allows one |
395 | EV will grab the signal for the process (the kernel only allows one |
326 | component to receive a signal at a time) when you start a signal |
396 | component to receive a signal at a time) when you start a signal |
327 | watcher, and removes it again when you stop it. Perl does the same |
397 | watcher, and removes it again when you stop it. Perl does the same |
328 | when you add/remove callbacks to %SIG, so watch out. |
398 | when you add/remove callbacks to %SIG, so watch out. |
… | |
… | |
332 | The "signal_ns" variant doesn't start (activate) the newly created |
402 | The "signal_ns" variant doesn't start (activate) the newly created |
333 | watcher. |
403 | watcher. |
334 | |
404 | |
335 | $w->set ($signal) |
405 | $w->set ($signal) |
336 | Reconfigures the watcher, see the constructor above for details. Can |
406 | Reconfigures the watcher, see the constructor above for details. Can |
337 | be at any time. |
407 | be called at any time. |
338 | |
408 | |
339 | $current_signum = $w->signal |
409 | $current_signum = $w->signal |
340 | $old_signum = $w->signal ($new_signal) |
410 | $old_signum = $w->signal ($new_signal) |
341 | Returns the previously set signal (always as a number not name) and |
411 | Returns the previously set signal (always as a number not name) and |
342 | optionally set a new one. |
412 | optionally set a new one. |
343 | |
413 | |
|
|
414 | CHILD WATCHERS - watch out for process status changes |
344 | $w = EV::child $pid, $callback |
415 | $w = EV::child $pid, $callback |
345 | $w = EV::child_ns $pid, $callback |
416 | $w = EV::child_ns $pid, $callback |
346 | Call the callback when a status change for pid $pid (or any pid if |
417 | Call the callback when a status change for pid $pid (or any pid if |
347 | $pid is 0) has been received. More precisely: when the process |
418 | $pid is 0) has been received. More precisely: when the process |
348 | receives a SIGCHLD, EV will fetch the outstanding exit/wait status |
419 | receives a "SIGCHLD", EV will fetch the outstanding exit/wait status |
349 | for all changed/zombie children and call the callback. |
420 | for all changed/zombie children and call the callback. |
350 | |
421 | |
351 | You can access both status and pid by using the "rstatus" and "rpid" |
422 | It is valid (and fully supported) to install a child watcher after a |
|
|
423 | child has exited but before the event loop has started its next |
|
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424 | iteration (for example, first you "fork", then the new child process |
|
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425 | might exit, and only then do you install a child watcher in the |
|
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426 | parent for the new pid). |
|
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427 | |
|
|
428 | You can access both exit (or tracing) status and pid by using the |
352 | methods on the watcher object. |
429 | "rstatus" and "rpid" methods on the watcher object. |
353 | |
430 | |
354 | You can have as many pid watchers per pid as you want. |
431 | You can have as many pid watchers per pid as you want, they will all |
|
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432 | be called. |
355 | |
433 | |
356 | The "child_ns" variant doesn't start (activate) the newly created |
434 | The "child_ns" variant doesn't start (activate) the newly created |
357 | watcher. |
435 | watcher. |
358 | |
436 | |
359 | $w->set ($pid) |
437 | $w->set ($pid) |
360 | Reconfigures the watcher, see the constructor above for details. Can |
438 | Reconfigures the watcher, see the constructor above for details. Can |
361 | be at any time. |
439 | be called at any time. |
362 | |
440 | |
363 | $current_pid = $w->pid |
441 | $current_pid = $w->pid |
364 | $old_pid = $w->pid ($new_pid) |
442 | $old_pid = $w->pid ($new_pid) |
365 | Returns the previously set process id and optionally set a new one. |
443 | Returns the previously set process id and optionally set a new one. |
366 | |
444 | |
… | |
… | |
370 | |
448 | |
371 | $pid = $w->rpid |
449 | $pid = $w->rpid |
372 | Return the pid of the awaited child (useful when you have installed |
450 | Return the pid of the awaited child (useful when you have installed |
373 | a watcher for all pids). |
451 | a watcher for all pids). |
374 | |
452 | |
|
|
453 | STAT WATCHERS - did the file attributes just change? |
|
|
454 | $w = EV::stat $path, $interval, $callback |
|
|
455 | $w = EV::stat_ns $path, $interval, $callback |
|
|
456 | Call the callback when a file status change has been detected on |
|
|
457 | $path. The $path does not need to exist, changing from "path exists" |
|
|
458 | to "path does not exist" is a status change like any other. |
|
|
459 | |
|
|
460 | The $interval is a recommended polling interval for systems where |
|
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461 | OS-supported change notifications don't exist or are not supported. |
|
|
462 | If you use 0 then an unspecified default is used (which is highly |
|
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463 | recommended!), which is to be expected to be around five seconds |
|
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464 | usually. |
|
|
465 | |
|
|
466 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
467 | as even with OS-supported change notifications, this can be |
|
|
468 | resource-intensive. |
|
|
469 | |
|
|
470 | The "stat_ns" variant doesn't start (activate) the newly created |
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471 | watcher. |
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472 | |
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473 | ... = $w->stat |
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474 | This call is very similar to the perl "stat" built-in: It stats |
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475 | (using "lstat") the path specified in the watcher and sets perls |
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476 | stat cache (as well as EV's idea of the current stat values) to the |
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477 | values found. |
|
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478 | |
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479 | In scalar context, a boolean is return indicating success or failure |
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480 | of the stat. In list context, the same 13-value list as with stat is |
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481 | returned (except that the blksize and blocks fields are not |
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482 | reliable). |
|
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483 | |
|
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484 | In the case of an error, errno is set to "ENOENT" (regardless of the |
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485 | actual error value) and the "nlink" value is forced to zero (if the |
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486 | stat was successful then nlink is guaranteed to be non-zero). |
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487 | |
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488 | See also the next two entries for more info. |
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489 | |
|
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490 | ... = $w->attr |
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491 | Just like "$w->stat", but without the initial stat'ing: this returns |
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492 | the values most recently detected by EV. See the next entry for more |
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493 | info. |
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494 | |
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495 | ... = $w->prev |
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496 | Just like "$w->stat", but without the initial stat'ing: this returns |
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497 | the previous set of values, before the change. |
|
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498 | |
|
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499 | That is, when the watcher callback is invoked, "$w->prev" will be |
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500 | set to the values found *before* a change was detected, while |
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501 | "$w->attr" returns the values found leading to the change detection. |
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502 | The difference (if any) between "prev" and "attr" is what triggered |
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503 | the callback. |
|
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504 | |
|
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505 | If you did something to the filesystem object and do not want to |
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506 | trigger yet another change, you can call "stat" to update EV's idea |
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507 | of what the current attributes are. |
|
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508 | |
|
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509 | $w->set ($path, $interval) |
|
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510 | Reconfigures the watcher, see the constructor above for details. Can |
|
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511 | be called at any time. |
|
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512 | |
|
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513 | $current_path = $w->path |
|
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514 | $old_path = $w->path ($new_path) |
|
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515 | Returns the previously set path and optionally set a new one. |
|
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516 | |
|
|
517 | $current_interval = $w->interval |
|
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518 | $old_interval = $w->interval ($new_interval) |
|
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519 | Returns the previously set interval and optionally set a new one. |
|
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520 | Can be used to query the actual interval used. |
|
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521 | |
|
|
522 | IDLE WATCHERS - when you've got nothing better to do... |
375 | $w = EV::idle $callback |
523 | $w = EV::idle $callback |
376 | $w = EV::idle_ns $callback |
524 | $w = EV::idle_ns $callback |
377 | Call the callback when there are no pending io, timer/periodic, |
525 | Call the callback when there are no pending io, timer/periodic, |
378 | signal or child events, i.e. when the process is idle. |
526 | signal or child events, i.e. when the process is idle. |
379 | |
527 | |
… | |
… | |
381 | and they will be called repeatedly until stopped. |
529 | and they will be called repeatedly until stopped. |
382 | |
530 | |
383 | The "idle_ns" variant doesn't start (activate) the newly created |
531 | The "idle_ns" variant doesn't start (activate) the newly created |
384 | watcher. |
532 | watcher. |
385 | |
533 | |
|
|
534 | PREPARE WATCHERS - customise your event loop! |
386 | $w = EV::prepare $callback |
535 | $w = EV::prepare $callback |
387 | $w = EV::prepare_ns $callback |
536 | $w = EV::prepare_ns $callback |
388 | Call the callback just before the process would block. You can still |
537 | Call the callback just before the process would block. You can still |
389 | create/modify any watchers at this point. |
538 | create/modify any watchers at this point. |
390 | |
539 | |
391 | See the EV::check watcher, below, for explanations and an example. |
540 | See the EV::check watcher, below, for explanations and an example. |
392 | |
541 | |
393 | The "prepare_ns" variant doesn't start (activate) the newly created |
542 | The "prepare_ns" variant doesn't start (activate) the newly created |
394 | watcher. |
543 | watcher. |
395 | |
544 | |
|
|
545 | CHECK WATCHERS - customise your event loop even more! |
396 | $w = EV::check $callback |
546 | $w = EV::check $callback |
397 | $w = EV::check_ns $callback |
547 | $w = EV::check_ns $callback |
398 | Call the callback just after the process wakes up again (after it |
548 | Call the callback just after the process wakes up again (after it |
399 | has gathered events), but before any other callbacks have been |
549 | has gathered events), but before any other callbacks have been |
400 | invoked. |
550 | invoked. |
… | |
… | |
411 | # do nothing unless active |
561 | # do nothing unless active |
412 | $dispatcher->{_event_queue_h} |
562 | $dispatcher->{_event_queue_h} |
413 | or return; |
563 | or return; |
414 | |
564 | |
415 | # make the dispatcher handle any outstanding stuff |
565 | # make the dispatcher handle any outstanding stuff |
|
|
566 | ... not shown |
416 | |
567 | |
417 | # create an IO watcher for each and every socket |
568 | # create an IO watcher for each and every socket |
418 | @snmp_watcher = ( |
569 | @snmp_watcher = ( |
419 | (map { EV::io $_, EV::READ, sub { } } |
570 | (map { EV::io $_, EV::READ, sub { } } |
420 | keys %{ $dispatcher->{_descriptors} }), |
571 | keys %{ $dispatcher->{_descriptors} }), |
|
|
572 | |
|
|
573 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
|
|
574 | ? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0), |
|
|
575 | 0, sub { }, |
421 | ); |
576 | ); |
422 | |
|
|
423 | # if there are any timeouts, also create a timer |
|
|
424 | push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { } |
|
|
425 | if $event->[Net::SNMP::Dispatcher::_ACTIVE]; |
|
|
426 | }; |
577 | }; |
427 | |
578 | |
428 | The callbacks are irrelevant, the only purpose of those watchers is |
579 | The callbacks are irrelevant (and are not even being called), the |
429 | to wake up the process as soon as one of those events occurs (socket |
580 | only purpose of those watchers is to wake up the process as soon as |
430 | readable, or timer timed out). The corresponding EV::check watcher |
581 | one of those events occurs (socket readable, or timer timed out). |
431 | will then clean up: |
582 | The corresponding EV::check watcher will then clean up: |
432 | |
583 | |
433 | our $snmp_check = EV::check sub { |
584 | our $snmp_check = EV::check sub { |
434 | # destroy all watchers |
585 | # destroy all watchers |
435 | @snmp_watcher = (); |
586 | @snmp_watcher = (); |
436 | |
587 | |
437 | # make the dispatcher handle any new stuff |
588 | # make the dispatcher handle any new stuff |
|
|
589 | ... not shown |
438 | }; |
590 | }; |
439 | |
591 | |
440 | The callbacks of the created watchers will not be called as the |
592 | The callbacks of the created watchers will not be called as the |
441 | watchers are destroyed before this cna happen (remember EV::check |
593 | watchers are destroyed before this cna happen (remember EV::check |
442 | gets called first). |
594 | gets called first). |
443 | |
595 | |
444 | The "check_ns" variant doesn't start (activate) the newly created |
596 | The "check_ns" variant doesn't start (activate) the newly created |
445 | watcher. |
597 | watcher. |
446 | |
598 | |
|
|
599 | FORK WATCHERS - the audacity to resume the event loop after a fork |
|
|
600 | Fork watchers are called when a "fork ()" was detected. The invocation |
|
|
601 | is done before the event loop blocks next and before "check" watchers |
|
|
602 | are being called, and only in the child after the fork. |
|
|
603 | |
|
|
604 | $w = EV::fork $callback |
|
|
605 | $w = EV::fork_ns $callback |
|
|
606 | Call the callback before the event loop is resumed in the child |
|
|
607 | process after a fork. |
|
|
608 | |
|
|
609 | The "fork_ns" variant doesn't start (activate) the newly created |
|
|
610 | watcher. |
|
|
611 | |
447 | THREADS |
612 | THREADS |
448 | Threads are not supported by this in any way. Perl pseudo-threads is |
613 | Threads are not supported by this module in any way. Perl pseudo-threads |
449 | evil stuff and must die. |
614 | is evil stuff and must die. As soon as Perl gains real threads I will |
|
|
615 | work on thread support for it. |
|
|
616 | |
|
|
617 | FORK |
|
|
618 | Most of the "improved" event delivering mechanisms of modern operating |
|
|
619 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
|
|
620 | not supported and usually destructive). Libev makes it possible to work |
|
|
621 | around this by having a function that recreates the kernel state after |
|
|
622 | fork in the child. |
|
|
623 | |
|
|
624 | On non-win32 platforms, this module requires the pthread_atfork |
|
|
625 | functionality to do this automatically for you. This function is quite |
|
|
626 | buggy on most BSDs, though, so YMMV. The overhead for this is quite |
|
|
627 | negligible, because everything the function currently does is set a flag |
|
|
628 | that is checked only when the event loop gets used the next time, so |
|
|
629 | when you do fork but not use EV, the overhead is minimal. |
|
|
630 | |
|
|
631 | On win32, there is no notion of fork so all this doesn't apply, of |
|
|
632 | course. |
450 | |
633 | |
451 | SEE ALSO |
634 | SEE ALSO |
452 | L<EV::DNS>, L<EV::AnyEvent>. |
635 | EV::DNS. |
453 | |
636 | |
454 | AUTHOR |
637 | AUTHOR |
455 | Marc Lehmann <schmorp@schmorp.de> |
638 | Marc Lehmann <schmorp@schmorp.de> |
456 | http://home.schmorp.de/ |
639 | http://home.schmorp.de/ |
457 | |
640 | |