… | |
… | |
9 | |
9 | |
10 | my $w = EV::timer 2, 0, sub { |
10 | my $w = EV::timer 2, 0, sub { |
11 | warn "is called after 2s"; |
11 | warn "is called after 2s"; |
12 | }; |
12 | }; |
13 | |
13 | |
14 | my $w = EV::timer 2, 1, sub { |
14 | my $w = EV::timer 2, 2, sub { |
15 | warn "is called roughly every 2s (repeat = 1)"; |
15 | warn "is called roughly every 2s (repeat = 2)"; |
16 | }; |
16 | }; |
17 | |
17 | |
18 | undef $w; # destroy event watcher again |
18 | undef $w; # destroy event watcher again |
19 | |
19 | |
20 | my $w = EV::periodic 0, 60, sub { |
20 | my $w = EV::periodic 0, 60, 0, sub { |
21 | warn "is called every minute, on the minute, exactly"; |
21 | warn "is called every minute, on the minute, exactly"; |
22 | }; |
22 | }; |
23 | |
23 | |
24 | # IO |
24 | # IO |
25 | |
25 | |
26 | my $w = EV::io *STDIN, EV::READ, sub { |
26 | my $w = EV::io *STDIN, EV::READ, sub { |
27 | my ($w, $revents) = @_; # all callbacks get the watcher object and event mask |
27 | my ($w, $revents) = @_; # all callbacks receive the watcher and event mask |
28 | warn "stdin is readable, you entered: ", <STDIN>; |
28 | warn "stdin is readable, you entered: ", <STDIN>; |
29 | }; |
29 | }; |
30 | |
30 | |
31 | # SIGNALS |
31 | # SIGNALS |
32 | |
32 | |
33 | my $w = EV::signal 'QUIT', sub { |
33 | my $w = EV::signal 'QUIT', sub { |
34 | warn "sigquit received\n"; |
34 | warn "sigquit received\n"; |
35 | }; |
35 | }; |
36 | |
36 | |
37 | my $w = EV::signal 3, sub { |
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38 | warn "sigquit received (this is GNU/Linux, right?)\n"; |
|
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39 | }; |
|
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40 | |
|
|
41 | # CHILD/PID STATUS CHANGES |
37 | # CHILD/PID STATUS CHANGES |
42 | |
38 | |
43 | my $w = EV::child 666, sub { |
39 | my $w = EV::child 666, sub { |
44 | my ($w, $revents, $status) = @_; |
40 | my ($w, $revents) = @_; |
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41 | my $status = $w->rstatus; |
|
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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"; |
45 | }; |
48 | }; |
46 | |
49 | |
47 | # MAINLOOP |
50 | # MAINLOOP |
48 | EV::loop; # loop until EV::loop_done is called |
51 | EV::loop; # loop until EV::unloop is called or all watchers stop |
49 | 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 |
50 | 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 |
51 | |
54 | |
52 | DESCRIPTION |
55 | DESCRIPTION |
53 | This module provides an interface to libev |
56 | This module provides an interface to libev |
54 | (<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". |
55 | |
62 | |
56 | BASIC INTERFACE |
63 | BASIC INTERFACE |
57 | $EV::DIED |
64 | $EV::DIED |
58 | 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 |
59 | callback throws an exception (with $@ containing thr error). The |
66 | callback throws an exception (with $@ containing thr error). The |
… | |
… | |
67 | $time = EV::now |
74 | $time = EV::now |
68 | Returns the time the last event loop iteration has been started. |
75 | Returns the time the last event loop iteration has been started. |
69 | 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 |
70 | to it is usually faster then calling EV::time. |
77 | to it is usually faster then calling EV::time. |
71 | |
78 | |
72 | $method = EV::ev_method |
79 | $method = EV::method |
73 | Returns an integer describing the backend used by libev |
80 | Returns an integer describing the backend used by libev |
74 | (EV::METHOD_SELECT or EV::METHOD_EPOLL). |
81 | (EV::METHOD_SELECT or EV::METHOD_EPOLL). |
75 | |
82 | |
76 | EV::loop [$flags] |
83 | EV::loop [$flags] |
77 | Begin checking for events and calling callbacks. It returns when a |
84 | Begin checking for events and calling callbacks. It returns when a |
78 | callback calls EV::loop_done. |
85 | callback calls EV::unloop. |
79 | |
86 | |
80 | The $flags argument can be one of the following: |
87 | The $flags argument can be one of the following: |
81 | |
88 | |
82 | 0 as above |
89 | 0 as above |
83 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
90 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
84 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
91 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
85 | |
92 | |
86 | EV::loop_done [$how] |
93 | EV::unloop [$how] |
87 | 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, |
88 | innermost call to EV::loop return. |
95 | makes the innermost call to EV::loop return. |
89 | |
96 | |
90 | 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 |
91 | as fast as possible. |
98 | EV::loop will return as fast as possible. |
92 | |
99 | |
93 | 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 |
94 | 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 |
95 | 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, |
96 | you would create an EV::io watcher for that: |
125 | you would create an EV::io watcher for that: |
97 | |
126 | |
98 | my $watcher = EV::io *STDIN, EV::READ, sub { |
127 | my $watcher = EV::io *STDIN, EV::READ, sub { |
… | |
… | |
115 | In the rare case where one wants to create a watcher but not start it at |
144 | In the rare case where one wants to create a watcher but not start it at |
116 | the same time, each constructor has a variant with a trailing "_ns" in |
145 | the same time, each constructor has a variant with a trailing "_ns" in |
117 | its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. |
146 | its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. |
118 | |
147 | |
119 | Please note that a watcher will automatically be stopped when the |
148 | Please note that a watcher will automatically be stopped when the |
120 | watcher object is returned, so you *need* to keep the watcher objects |
149 | watcher object is destroyed, so you *need* to keep the watcher objects |
121 | returned by the constructors. |
150 | returned by the constructors. |
122 | |
151 | |
123 | WATCHER TYPES |
152 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
124 | Now lets move to the existing watcher types and asociated methods. |
153 | ->fh and so on) automatically stop and start it again if it is active, |
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154 | which means pending events get lost. |
125 | |
155 | |
126 | The following methods are available for all watchers. Then followes a |
156 | COMMON WATCHER METHODS |
127 | description of each watcher constructor (EV::io, EV::timer, |
157 | This section lists methods common to all watchers. |
128 | EV::periodic, EV::signal, EV::child, EV::idle, EV::prepare and |
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129 | EV::check), followed by any type-specific methods (if any). |
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130 | |
158 | |
131 | $w->start |
159 | $w->start |
132 | 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 |
133 | already active watcher. By default, all watchers start out in the |
161 | already active watcher. By default, all watchers start out in the |
134 | 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 |
… | |
… | |
141 | not. |
169 | not. |
142 | |
170 | |
143 | $bool = $w->is_active |
171 | $bool = $w->is_active |
144 | Returns true if the watcher is active, false otherwise. |
172 | Returns true if the watcher is active, false otherwise. |
145 | |
173 | |
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174 | $current_data = $w->data |
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175 | $old_data = $w->data ($new_data) |
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176 | Queries a freely usable data scalar on the watcher and optionally |
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177 | changes it. This is a way to associate custom data with a watcher: |
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178 | |
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179 | my $w = EV::timer 60, 0, sub { |
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180 | warn $_[0]->data; |
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181 | }; |
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182 | $w->data ("print me!"); |
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183 | |
146 | $current_cb = $w->cb |
184 | $current_cb = $w->cb |
147 | $old_cb = $w->cb ($new_cb) |
185 | $old_cb = $w->cb ($new_cb) |
148 | Queries the callback on the watcher and optionally changes it. You |
186 | Queries the callback on the watcher and optionally changes it. You |
149 | cna do this at any time. |
187 | can do this at any time without the watcher restarting. |
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188 | |
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189 | $current_priority = $w->priority |
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190 | $old_priority = $w->priority ($new_priority) |
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191 | Queries the priority on the watcher and optionally changes it. |
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192 | Pending watchers with higher priority will be invoked first. The |
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193 | valid range of priorities lies between EV::MAXPRI (default 2) and |
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194 | EV::MINPRI (default -2). If the priority is outside this range it |
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195 | will automatically be normalised to the nearest valid priority. |
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196 | |
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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. |
150 | |
201 | |
151 | $w->trigger ($revents) |
202 | $w->trigger ($revents) |
152 | Call the callback *now* with the given event mask. |
203 | Call the callback *now* with the given event mask. |
153 | |
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? |
154 | $w = EV::io $fileno_or_fh, $eventmask, $callback |
239 | $w = EV::io $fileno_or_fh, $eventmask, $callback |
155 | $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
240 | $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
156 | 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 |
157 | when the events specified in $eventmask. |
242 | when at least one of events specified in $eventmask occurs. |
158 | |
243 | |
159 | 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: |
160 | |
245 | |
161 | EV::READ wait until read() wouldn't block anymore |
246 | EV::READ wait until read() wouldn't block anymore |
162 | EV::WRITE wait until write() wouldn't block anymore |
247 | EV::WRITE wait until write() wouldn't block anymore |
… | |
… | |
174 | |
259 | |
175 | $current_eventmask = $w->events |
260 | $current_eventmask = $w->events |
176 | $old_eventmask = $w->events ($new_eventmask) |
261 | $old_eventmask = $w->events ($new_eventmask) |
177 | 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. |
178 | |
263 | |
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264 | TIMER WATCHERS - relative and optionally repeating timeouts |
179 | $w = EV::timer $after, $repeat, $callback |
265 | $w = EV::timer $after, $repeat, $callback |
180 | $w = EV::timer_ns $after, $repeat, $callback |
266 | $w = EV::timer_ns $after, $repeat, $callback |
181 | Calls the callback after $after seconds. If $repeat is non-zero, the |
267 | Calls the callback after $after seconds (which may be fractional). |
182 | 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 |
183 | callback returns. |
269 | $repeat value as $after) after the callback returns. |
184 | |
270 | |
185 | This means that the callback would be called roughly after $after |
271 | This means that the callback would be called roughly after $after |
186 | seconds, and then every $repeat seconds. "Roughly" because the time |
272 | seconds, and then every $repeat seconds. The timer does his best not |
187 | 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 |
188 | 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. |
189 | |
277 | |
190 | 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 |
191 | 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 |
192 | changes the system clock, the timer will nevertheless run (roughly) |
280 | changes the system clock, the timer will nevertheless run (roughly) |
193 | the same time. |
281 | the same time. |
194 | |
282 | |
195 | The "timer_ns" variant doesn't start (activate) the newly created |
283 | The "timer_ns" variant doesn't start (activate) the newly created |
196 | watcher. |
284 | watcher. |
197 | |
285 | |
198 | $w->set ($after, $repeat) |
286 | $w->set ($after, $repeat) |
199 | Reconfigures the watcher, see the constructor above for details. Can |
287 | Reconfigures the watcher, see the constructor above for details. Can |
200 | be at any time. |
288 | be called at any time. |
201 | |
289 | |
202 | $w->again |
290 | $w->again |
203 | Similar to the "start" method, but has special semantics for |
291 | Similar to the "start" method, but has special semantics for |
204 | repeating timers: |
292 | repeating timers: |
205 | |
293 | |
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294 | If the timer is active and non-repeating, it will be stopped. |
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295 | |
206 | 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 |
207 | $repeat seconds after now. |
297 | $repeat seconds after now. |
208 | |
298 | |
209 | If the timer is active and non-repeating, it will be stopped. |
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210 | |
|
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211 | 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. |
212 | |
301 | |
213 | Otherwise do nothing. |
302 | Otherwise do nothing. |
214 | |
303 | |
215 | 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 |
216 | 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 |
217 | 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" |
218 | method on the timeout. |
307 | method on the timeout. |
219 | |
308 | |
|
|
309 | PERIODIC WATCHERS - to cron or not to cron? |
220 | $w = EV::periodic $at, $interval, $callback |
310 | $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
221 | $w = EV::periodic_ns $at, $interval, $callback |
311 | $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
222 | Similar to EV::timer, but the time is given as an absolute point in |
312 | Similar to EV::timer, but is not based on relative timeouts but on |
223 | time ($at), plus an optional $interval. |
313 | absolute times. Apart from creating "simple" timers that trigger |
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314 | "at" the specified time, it can also be used for non-drifting |
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315 | absolute timers and more complex, cron-like, setups that are not |
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316 | adversely affected by time jumps (i.e. when the system clock is |
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317 | changed by explicit date -s or other means such as ntpd). It is also |
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318 | the most complex watcher type in EV. |
224 | |
319 | |
225 | If the $interval is zero, then the callback will be called at the |
320 | It has three distinct "modes": |
226 | time $at if that is in the future, or as soon as possible if it is |
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227 | in the past. It will not automatically repeat. |
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228 | |
321 | |
229 | If the $interval is nonzero, then the watcher will always be |
322 | * absolute timer ($interval = $reschedule_cb = 0) |
230 | scheduled to time out at the next "$at + N * $interval" time. |
323 | This time simply fires at the wallclock time $at and doesn't |
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324 | repeat. It will not adjust when a time jump occurs, that is, if |
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325 | it is to be run at January 1st 2011 then it will run when the |
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326 | system time reaches or surpasses this time. |
231 | |
327 | |
232 | This can be used to schedule a callback to run at very regular |
328 | * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) |
233 | intervals, as long as the processing time is less then the interval |
329 | In this mode the watcher will always be scheduled to time out at |
234 | (otherwise obviously events will be skipped). |
330 | the next "$at + N * $interval" time (for some integer N) and |
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331 | then repeat, regardless of any time jumps. |
235 | |
332 | |
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333 | This can be used to create timers that do not drift with respect |
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334 | to system time: |
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335 | |
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336 | my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; |
|
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337 | |
|
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338 | That doesn't mean there will always be 3600 seconds in between |
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339 | triggers, but only that the the clalback will be called when the |
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340 | system time shows a full hour (UTC). |
|
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341 | |
236 | Another way to think about it (for the mathematically inclined) is |
342 | Another way to think about it (for the mathematically inclined) |
237 | that EV::periodic will try to run the callback at the next possible |
343 | is that EV::periodic will try to run the callback in this mode |
238 | time where "$time = $at (mod $interval)", regardless of any time |
344 | at the next possible time where "$time = $at (mod $interval)", |
239 | jumps. |
345 | regardless of any time jumps. |
240 | |
346 | |
241 | This periodic timer is based on "wallclock time", that is, if the |
347 | * manual reschedule mode ($reschedule_cb = coderef) |
242 | clock changes ("ntp", "date -s" etc.), then the timer will |
348 | In this mode $interval and $at are both being ignored. Instead, |
243 | nevertheless run at the specified time. This means it will never |
349 | each time the periodic watcher gets scheduled, the reschedule |
244 | drift (it might jitter, but it will not drift). |
350 | callback ($reschedule_cb) will be called with the watcher as |
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351 | first, and the current time as second argument. |
|
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352 | |
|
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353 | *This callback MUST NOT stop or destroy this or any other |
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354 | periodic watcher, ever*. If you need to stop it, return 1e30 and |
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355 | stop it afterwards. |
|
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356 | |
|
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357 | It must return the next time to trigger, based on the passed |
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358 | time value (that is, the lowest time value larger than to the |
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359 | second argument). It will usually be called just before the |
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360 | callback will be triggered, but might be called at other times, |
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361 | too. |
|
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362 | |
|
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363 | This can be used to create very complex timers, such as a timer |
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364 | that triggers on each midnight, local time (actually 24 hours |
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365 | after the last midnight, to keep the example simple. If you know |
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366 | a way to do it correctly in about the same space (without |
|
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367 | requiring elaborate modules), drop me a note :): |
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368 | |
|
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369 | my $daily = EV::periodic 0, 0, sub { |
|
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370 | my ($w, $now) = @_; |
|
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371 | |
|
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372 | use Time::Local (); |
|
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373 | my (undef, undef, undef, $d, $m, $y) = localtime $now; |
|
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374 | 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y |
|
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375 | }, sub { |
|
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376 | print "it's midnight or likely shortly after, now\n"; |
|
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377 | }; |
245 | |
378 | |
246 | The "periodic_ns" variant doesn't start (activate) the newly created |
379 | The "periodic_ns" variant doesn't start (activate) the newly created |
247 | watcher. |
380 | watcher. |
248 | |
381 | |
249 | $w->set ($at, $interval) |
382 | $w->set ($at, $interval, $reschedule_cb) |
250 | Reconfigures the watcher, see the constructor above for details. Can |
383 | Reconfigures the watcher, see the constructor above for details. Can |
251 | be at any time. |
384 | be called at any time. |
252 | |
385 | |
|
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386 | $w->again |
|
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387 | Simply stops and starts the watcher again. |
|
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388 | |
|
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389 | SIGNAL WATCHERS - signal me when a signal gets signalled! |
253 | $w = EV::signal $signal, $callback |
390 | $w = EV::signal $signal, $callback |
254 | $w = EV::signal_ns $signal, $callback |
391 | $w = EV::signal_ns $signal, $callback |
255 | Call the callback when $signal is received (the signal can be |
392 | Call the callback when $signal is received (the signal can be |
256 | 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). |
257 | |
394 | |
258 | 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 |
259 | 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 |
260 | 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 |
261 | when you add/remove callbacks to %SIG, so watch out. |
398 | when you add/remove callbacks to %SIG, so watch out. |
… | |
… | |
265 | The "signal_ns" variant doesn't start (activate) the newly created |
402 | The "signal_ns" variant doesn't start (activate) the newly created |
266 | watcher. |
403 | watcher. |
267 | |
404 | |
268 | $w->set ($signal) |
405 | $w->set ($signal) |
269 | Reconfigures the watcher, see the constructor above for details. Can |
406 | Reconfigures the watcher, see the constructor above for details. Can |
270 | be at any time. |
407 | be called at any time. |
271 | |
408 | |
|
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409 | $current_signum = $w->signal |
|
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410 | $old_signum = $w->signal ($new_signal) |
|
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411 | Returns the previously set signal (always as a number not name) and |
|
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412 | optionally set a new one. |
|
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413 | |
|
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414 | CHILD WATCHERS - watch out for process status changes |
272 | $w = EV::child $pid, $callback |
415 | $w = EV::child $pid, $callback |
273 | $w = EV::child_ns $pid, $callback |
416 | $w = EV::child_ns $pid, $callback |
274 | 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 |
275 | $pid is 0) has been received. More precisely: when the process |
418 | $pid is 0) has been received. More precisely: when the process |
276 | receives a SIGCHLD, EV will fetch the outstanding exit/wait status |
419 | receives a "SIGCHLD", EV will fetch the outstanding exit/wait status |
277 | for all changed/zombie children and call the callback. |
420 | for all changed/zombie children and call the callback. |
278 | |
421 | |
279 | Unlike all other callbacks, this callback will be called with an |
422 | It is valid (and fully supported) to install a child watcher after a |
280 | additional third argument which is the exit status. See the |
423 | child has exited but before the event loop has started its next |
281 | "waitpid" function for details. |
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). |
282 | |
427 | |
|
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428 | You can access both exit (or tracing) status and pid by using the |
|
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429 | "rstatus" and "rpid" methods on the watcher object. |
|
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430 | |
283 | 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. |
284 | |
433 | |
285 | The "child_ns" variant doesn't start (activate) the newly created |
434 | The "child_ns" variant doesn't start (activate) the newly created |
286 | watcher. |
435 | watcher. |
287 | |
436 | |
288 | $w->set ($pid) |
437 | $w->set ($pid) |
289 | Reconfigures the watcher, see the constructor above for details. Can |
438 | Reconfigures the watcher, see the constructor above for details. Can |
290 | be at any time. |
439 | be called at any time. |
291 | |
440 | |
|
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441 | $current_pid = $w->pid |
|
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442 | $old_pid = $w->pid ($new_pid) |
|
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443 | Returns the previously set process id and optionally set a new one. |
|
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444 | |
|
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445 | $exit_status = $w->rstatus |
|
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446 | Return the exit/wait status (as returned by waitpid, see the waitpid |
|
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447 | entry in perlfunc). |
|
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448 | |
|
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449 | $pid = $w->rpid |
|
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450 | Return the pid of the awaited child (useful when you have installed |
|
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451 | a watcher for all pids). |
|
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452 | |
|
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453 | STAT WATCHERS - did the file attributes just change? |
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454 | $w = EV::stat $path, $interval, $callback |
|
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455 | $w = EV::stat_ns $path, $interval, $callback |
|
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456 | Call the callback when a file status change has been detected on |
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457 | $path. The $path does not need to exist, changing from "path exists" |
|
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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 | |
|
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466 | This watcher type is not meant for massive numbers of stat watchers, |
|
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467 | as even with OS-supported change notifications, this can be |
|
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468 | resource-intensive. |
|
|
469 | |
|
|
470 | The "stat_ns" variant doesn't start (activate) the newly created |
|
|
471 | watcher. |
|
|
472 | |
|
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473 | $w->set ($path, $interval) |
|
|
474 | Reconfigures the watcher, see the constructor above for details. Can |
|
|
475 | be called at any time. |
|
|
476 | |
|
|
477 | $current_path = $w->path |
|
|
478 | $old_path = $w->path ($new_path) |
|
|
479 | Returns the previously set path and optionally set a new one. |
|
|
480 | |
|
|
481 | $current_interval = $w->interval |
|
|
482 | $old_interval = $w->interval ($new_interval) |
|
|
483 | Returns the previously set interval and optionally set a new one. |
|
|
484 | Can be used to query the actual interval used. |
|
|
485 | |
|
|
486 | IDLE WATCHERS - when you've got nothing better to do... |
292 | $w = EV::idle $callback |
487 | $w = EV::idle $callback |
293 | $w = EV::idle_ns $callback |
488 | $w = EV::idle_ns $callback |
294 | Call the callback when there are no pending io, timer/periodic, |
489 | Call the callback when there are no pending io, timer/periodic, |
295 | signal or child events, i.e. when the process is idle. |
490 | signal or child events, i.e. when the process is idle. |
296 | |
491 | |
… | |
… | |
298 | and they will be called repeatedly until stopped. |
493 | and they will be called repeatedly until stopped. |
299 | |
494 | |
300 | The "idle_ns" variant doesn't start (activate) the newly created |
495 | The "idle_ns" variant doesn't start (activate) the newly created |
301 | watcher. |
496 | watcher. |
302 | |
497 | |
|
|
498 | PREPARE WATCHERS - customise your event loop! |
303 | $w = EV::prepare $callback |
499 | $w = EV::prepare $callback |
304 | $w = EV::prepare_ns $callback |
500 | $w = EV::prepare_ns $callback |
305 | Call the callback just before the process would block. You can still |
501 | Call the callback just before the process would block. You can still |
306 | create/modify any watchers at this point. |
502 | create/modify any watchers at this point. |
307 | |
503 | |
308 | See the EV::check watcher, below, for explanations and an example. |
504 | See the EV::check watcher, below, for explanations and an example. |
309 | |
505 | |
310 | The "prepare_ns" variant doesn't start (activate) the newly created |
506 | The "prepare_ns" variant doesn't start (activate) the newly created |
311 | watcher. |
507 | watcher. |
312 | |
508 | |
|
|
509 | CHECK WATCHERS - customise your event loop even more! |
313 | $w = EV::check $callback |
510 | $w = EV::check $callback |
314 | $w = EV::check_ns $callback |
511 | $w = EV::check_ns $callback |
315 | Call the callback just after the process wakes up again (after it |
512 | Call the callback just after the process wakes up again (after it |
316 | has gathered events), but before any other callbacks have been |
513 | has gathered events), but before any other callbacks have been |
317 | invoked. |
514 | invoked. |
… | |
… | |
328 | # do nothing unless active |
525 | # do nothing unless active |
329 | $dispatcher->{_event_queue_h} |
526 | $dispatcher->{_event_queue_h} |
330 | or return; |
527 | or return; |
331 | |
528 | |
332 | # make the dispatcher handle any outstanding stuff |
529 | # make the dispatcher handle any outstanding stuff |
|
|
530 | ... not shown |
333 | |
531 | |
334 | # create an IO watcher for each and every socket |
532 | # create an IO watcher for each and every socket |
335 | @snmp_watcher = ( |
533 | @snmp_watcher = ( |
336 | (map { EV::io $_, EV::READ, sub { } } |
534 | (map { EV::io $_, EV::READ, sub { } } |
337 | keys %{ $dispatcher->{_descriptors} }), |
535 | keys %{ $dispatcher->{_descriptors} }), |
|
|
536 | |
|
|
537 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
|
|
538 | ? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0), |
|
|
539 | 0, sub { }, |
338 | ); |
540 | ); |
339 | |
|
|
340 | # if there are any timeouts, also create a timer |
|
|
341 | push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { } |
|
|
342 | if $event->[Net::SNMP::Dispatcher::_ACTIVE]; |
|
|
343 | }; |
541 | }; |
344 | |
542 | |
345 | The callbacks are irrelevant, the only purpose of those watchers is |
543 | The callbacks are irrelevant (and are not even being called), the |
346 | to wake up the process as soon as one of those events occurs (socket |
544 | only purpose of those watchers is to wake up the process as soon as |
347 | readable, or timer timed out). The corresponding EV::check watcher |
545 | one of those events occurs (socket readable, or timer timed out). |
348 | will then clean up: |
546 | The corresponding EV::check watcher will then clean up: |
349 | |
547 | |
350 | our $snmp_check = EV::check sub { |
548 | our $snmp_check = EV::check sub { |
351 | # destroy all watchers |
549 | # destroy all watchers |
352 | @snmp_watcher = (); |
550 | @snmp_watcher = (); |
353 | |
551 | |
354 | # make the dispatcher handle any new stuff |
552 | # make the dispatcher handle any new stuff |
|
|
553 | ... not shown |
355 | }; |
554 | }; |
356 | |
555 | |
357 | The callbacks of the created watchers will not be called as the |
556 | The callbacks of the created watchers will not be called as the |
358 | watchers are destroyed before this cna happen (remember EV::check |
557 | watchers are destroyed before this cna happen (remember EV::check |
359 | gets called first). |
558 | gets called first). |
360 | |
559 | |
361 | The "check_ns" variant doesn't start (activate) the newly created |
560 | The "check_ns" variant doesn't start (activate) the newly created |
362 | watcher. |
561 | watcher. |
363 | |
562 | |
|
|
563 | FORK WATCHERS - the audacity to resume the event loop after a fork |
|
|
564 | Fork watchers are called when a "fork ()" was detected. The invocation |
|
|
565 | is done before the event loop blocks next and before "check" watchers |
|
|
566 | are being called, and only in the child after the fork. |
|
|
567 | |
|
|
568 | $w = EV::fork $callback |
|
|
569 | $w = EV::fork_ns $callback |
|
|
570 | Call the callback before the event loop is resumed in the child |
|
|
571 | process after a fork. |
|
|
572 | |
|
|
573 | The "fork_ns" variant doesn't start (activate) the newly created |
|
|
574 | watcher. |
|
|
575 | |
364 | THREADS |
576 | THREADS |
365 | Threads are not supported by this in any way. Perl pseudo-threads is |
577 | Threads are not supported by this module in any way. Perl pseudo-threads |
366 | evil stuff and must die. |
578 | is evil stuff and must die. As soon as Perl gains real threads I will |
|
|
579 | work on thread support for it. |
|
|
580 | |
|
|
581 | FORK |
|
|
582 | Most of the "improved" event delivering mechanisms of modern operating |
|
|
583 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
|
|
584 | not supported and usually destructive). Libev makes it possible to work |
|
|
585 | around this by having a function that recreates the kernel state after |
|
|
586 | fork in the child. |
|
|
587 | |
|
|
588 | On non-win32 platforms, this module requires the pthread_atfork |
|
|
589 | functionality to do this automatically for you. This function is quite |
|
|
590 | buggy on most BSDs, though, so YMMV. The overhead for this is quite |
|
|
591 | negligible, because everything the function currently does is set a flag |
|
|
592 | that is checked only when the event loop gets used the next time, so |
|
|
593 | when you do fork but not use EV, the overhead is minimal. |
|
|
594 | |
|
|
595 | On win32, there is no notion of fork so all this doesn't apply, of |
|
|
596 | course. |
367 | |
597 | |
368 | SEE ALSO |
598 | SEE ALSO |
369 | L<EV::DNS>, L<EV::AnyEvent>. |
599 | EV::DNS. |
370 | |
600 | |
371 | AUTHOR |
601 | AUTHOR |
372 | Marc Lehmann <schmorp@schmorp.de> |
602 | Marc Lehmann <schmorp@schmorp.de> |
373 | http://home.schmorp.de/ |
603 | http://home.schmorp.de/ |
374 | |
604 | |