… | |
… | |
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, $revents) = @_; |
40 | my ($w, $revents) = @_; |
45 | # my $pid = $w->rpid; |
|
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46 | my $status = $w->rstatus; |
41 | my $status = $w->rstatus; |
47 | }; |
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 | }; |
48 | |
49 | |
49 | # MAINLOOP |
50 | # MAINLOOP |
50 | EV::loop; # loop until EV::loop_done is called |
51 | EV::loop; # loop until EV::unloop is called or all watchers stop |
51 | 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 |
52 | 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 |
53 | |
54 | |
54 | DESCRIPTION |
55 | DESCRIPTION |
55 | This module provides an interface to libev |
56 | This module provides an interface to libev |
56 | (<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", or just |
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62 | about in any case because it has much more detailed information. |
57 | |
63 | |
58 | BASIC INTERFACE |
64 | BASIC INTERFACE |
59 | $EV::DIED |
65 | $EV::DIED |
60 | Must contain a reference to a function that is called when a |
66 | Must contain a reference to a function that is called when a |
61 | callback throws an exception (with $@ containing thr error). The |
67 | callback throws an exception (with $@ containing thr error). The |
… | |
… | |
69 | $time = EV::now |
75 | $time = EV::now |
70 | Returns the time the last event loop iteration has been started. |
76 | Returns the time the last event loop iteration has been started. |
71 | This is the time that (relative) timers are based on, and refering |
77 | This is the time that (relative) timers are based on, and refering |
72 | to it is usually faster then calling EV::time. |
78 | to it is usually faster then calling EV::time. |
73 | |
79 | |
74 | $method = EV::ev_method |
80 | $method = EV::method |
75 | Returns an integer describing the backend used by libev |
81 | Returns an integer describing the backend used by libev |
76 | (EV::METHOD_SELECT or EV::METHOD_EPOLL). |
82 | (EV::METHOD_SELECT or EV::METHOD_EPOLL). |
77 | |
83 | |
78 | EV::loop [$flags] |
84 | EV::loop [$flags] |
79 | Begin checking for events and calling callbacks. It returns when a |
85 | Begin checking for events and calling callbacks. It returns when a |
80 | callback calls EV::loop_done. |
86 | callback calls EV::unloop. |
81 | |
87 | |
82 | The $flags argument can be one of the following: |
88 | The $flags argument can be one of the following: |
83 | |
89 | |
84 | 0 as above |
90 | 0 as above |
85 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
91 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
86 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
92 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
87 | |
93 | |
88 | EV::loop_done [$how] |
94 | EV::unloop [$how] |
89 | When called with no arguments or an argument of 1, makes the |
95 | When called with no arguments or an argument of EV::UNLOOP_ONE, |
90 | innermost call to EV::loop return. |
96 | makes the innermost call to EV::loop return. |
91 | |
97 | |
92 | When called with an agrument of 2, all calls to EV::loop will return |
98 | When called with an argument of EV::UNLOOP_ALL, all calls to |
93 | as fast as possible. |
99 | EV::loop will return as fast as possible. |
94 | |
100 | |
95 | WATCHER |
101 | $count = EV::loop_count |
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102 | Return the number of times the event loop has polled for new events. |
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103 | Sometiems useful as a generation counter. |
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104 | |
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105 | EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
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106 | This function rolls together an I/O and a timer watcher for a single |
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107 | one-shot event without the need for managing a watcher object. |
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108 | |
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109 | If $fh_or_undef is a filehandle or file descriptor, then $events |
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110 | must be a bitset containing either "EV::READ", "EV::WRITE" or |
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111 | "EV::READ | EV::WRITE", indicating the type of I/O event you want to |
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112 | wait for. If you do not want to wait for some I/O event, specify |
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113 | "undef" for $fh_or_undef and 0 for $events). |
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114 | |
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115 | If timeout is "undef" or negative, then there will be no timeout. |
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116 | Otherwise a EV::timer with this value will be started. |
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117 | |
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118 | When an error occurs or either the timeout or I/O watcher triggers, |
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119 | then the callback will be called with the received event set (in |
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120 | general you can expect it to be a combination of "EV:ERROR", |
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121 | "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). |
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122 | |
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123 | EV::once doesn't return anything: the watchers stay active till |
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124 | either of them triggers, then they will be stopped and freed, and |
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125 | the callback invoked. |
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126 | |
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127 | EV::feed_fd_event ($fd, $revents) |
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128 | Feed an event on a file descriptor into EV. EV will react to this |
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129 | call as if the readyness notifications specified by $revents (a |
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130 | combination of "EV::READ" and "EV::WRITE") happened on the file |
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131 | descriptor $fd. |
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132 | |
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133 | EV::feed_signal_event ($signal) |
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134 | Feed a signal event into EV. EV will react to this call as if the |
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135 | signal specified by $signal had occured. |
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136 | |
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137 | WATCHER OBJECTS |
96 | A watcher is an object that gets created to record your interest in some |
138 | A watcher is an object that gets created to record your interest in some |
97 | event. For instance, if you want to wait for STDIN to become readable, |
139 | event. For instance, if you want to wait for STDIN to become readable, |
98 | you would create an EV::io watcher for that: |
140 | you would create an EV::io watcher for that: |
99 | |
141 | |
100 | my $watcher = EV::io *STDIN, EV::READ, sub { |
142 | my $watcher = EV::io *STDIN, EV::READ, sub { |
… | |
… | |
108 | received events. |
150 | received events. |
109 | |
151 | |
110 | Each watcher type has its associated bit in revents, so you can use the |
152 | Each watcher type has its associated bit in revents, so you can use the |
111 | same callback for multiple watchers. The event mask is named after the |
153 | same callback for multiple watchers. The event mask is named after the |
112 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
154 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
113 | EV::periodic sets EV::PERIODIC and so on, with the exception of IO |
155 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O |
114 | events (which can set both EV::READ and EV::WRITE bits), and EV::timer |
156 | events (which can set both EV::READ and EV::WRITE bits), and EV::timer |
115 | (which uses EV::TIMEOUT). |
157 | (which uses EV::TIMEOUT). |
116 | |
158 | |
117 | In the rare case where one wants to create a watcher but not start it at |
159 | In the rare case where one wants to create a watcher but not start it at |
118 | the same time, each constructor has a variant with a trailing "_ns" in |
160 | the same time, each constructor has a variant with a trailing "_ns" in |
… | |
… | |
124 | |
166 | |
125 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
167 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
126 | ->fh and so on) automatically stop and start it again if it is active, |
168 | ->fh and so on) automatically stop and start it again if it is active, |
127 | which means pending events get lost. |
169 | which means pending events get lost. |
128 | |
170 | |
129 | WATCHER TYPES |
171 | COMMON WATCHER METHODS |
130 | Now lets move to the existing watcher types and asociated methods. |
172 | This section lists methods common to all watchers. |
131 | |
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132 | The following methods are available for all watchers. Then followes a |
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133 | description of each watcher constructor (EV::io, EV::timer, |
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134 | EV::periodic, EV::signal, EV::child, EV::idle, EV::prepare and |
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135 | EV::check), followed by any type-specific methods (if any). |
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136 | |
173 | |
137 | $w->start |
174 | $w->start |
138 | Starts a watcher if it isn't active already. Does nothing to an |
175 | Starts a watcher if it isn't active already. Does nothing to an |
139 | already active watcher. By default, all watchers start out in the |
176 | already active watcher. By default, all watchers start out in the |
140 | active state (see the description of the "_ns" variants if you need |
177 | active state (see the description of the "_ns" variants if you need |
141 | stopped watchers). |
178 | stopped watchers). |
142 | |
179 | |
143 | $w->stop |
180 | $w->stop |
144 | Stop a watcher if it is active. Also clear any pending events |
181 | Stop a watcher if it is active. Also clear any pending events |
145 | (events that have been received but that didn't yet result in a |
182 | (events that have been received but that didn't yet result in a |
146 | callback invocation), regardless of wether the watcher was active or |
183 | callback invocation), regardless of whether the watcher was active |
147 | not. |
184 | or not. |
148 | |
185 | |
149 | $bool = $w->is_active |
186 | $bool = $w->is_active |
150 | Returns true if the watcher is active, false otherwise. |
187 | Returns true if the watcher is active, false otherwise. |
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188 | |
|
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189 | $current_data = $w->data |
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190 | $old_data = $w->data ($new_data) |
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191 | Queries a freely usable data scalar on the watcher and optionally |
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192 | changes it. This is a way to associate custom data with a watcher: |
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193 | |
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194 | my $w = EV::timer 60, 0, sub { |
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195 | warn $_[0]->data; |
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196 | }; |
|
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197 | $w->data ("print me!"); |
151 | |
198 | |
152 | $current_cb = $w->cb |
199 | $current_cb = $w->cb |
153 | $old_cb = $w->cb ($new_cb) |
200 | $old_cb = $w->cb ($new_cb) |
154 | Queries the callback on the watcher and optionally changes it. You |
201 | Queries the callback on the watcher and optionally changes it. You |
155 | can do this at any time without the watcher restarting. |
202 | can do this at any time without the watcher restarting. |
… | |
… | |
160 | Pending watchers with higher priority will be invoked first. The |
207 | Pending watchers with higher priority will be invoked first. The |
161 | valid range of priorities lies between EV::MAXPRI (default 2) and |
208 | valid range of priorities lies between EV::MAXPRI (default 2) and |
162 | EV::MINPRI (default -2). If the priority is outside this range it |
209 | EV::MINPRI (default -2). If the priority is outside this range it |
163 | will automatically be normalised to the nearest valid priority. |
210 | will automatically be normalised to the nearest valid priority. |
164 | |
211 | |
165 | The default priority of any newly-created weatcher is 0. |
212 | The default priority of any newly-created watcher is 0. |
166 | |
213 | |
|
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214 | Note that the priority semantics have not yet been fleshed out and |
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215 | are subject to almost certain change. |
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216 | |
167 | $w->trigger ($revents) |
217 | $w->invoke ($revents) |
168 | Call the callback *now* with the given event mask. |
218 | Call the callback *now* with the given event mask. |
169 | |
219 | |
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220 | $w->feed_event ($revents) |
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221 | Feed some events on this watcher into EV. EV will react to this call |
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222 | as if the watcher had received the given $revents mask. |
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223 | |
|
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224 | $revents = $w->clear_pending |
|
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225 | If the watcher is pending, this function returns clears its pending |
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226 | status and returns its $revents bitset (as if its callback was |
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227 | invoked). If the watcher isn't pending it does nothing and returns |
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228 | 0. |
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229 | |
|
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230 | $previous_state = $w->keepalive ($bool) |
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231 | Normally, "EV::loop" will return when there are no active watchers |
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232 | (which is a "deadlock" because no progress can be made anymore). |
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233 | This is convinient because it allows you to start your watchers (and |
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234 | your jobs), call "EV::loop" once and when it returns you know that |
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235 | all your jobs are finished (or they forgot to register some watchers |
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236 | for their task :). |
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237 | |
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238 | Sometimes, however, this gets in your way, for example when you the |
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239 | module that calls "EV::loop" (usually the main program) is not the |
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240 | same module as a long-living watcher (for example a DNS client |
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241 | module written by somebody else even). Then you might want any |
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242 | outstanding requests to be handled, but you would not want to keep |
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243 | "EV::loop" from returning just because you happen to have this |
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244 | long-running UDP port watcher. |
|
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245 | |
|
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246 | In this case you can clear the keepalive status, which means that |
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247 | even though your watcher is active, it won't keep "EV::loop" from |
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248 | returning. |
|
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249 | |
|
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250 | The initial value for keepalive is true (enabled), and you cna |
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251 | change it any time. |
|
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252 | |
|
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253 | Example: Register an I/O watcher for some UDP socket but do not keep |
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254 | the event loop from running just because of that watcher. |
|
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255 | |
|
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256 | my $udp_socket = ... |
|
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257 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
|
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258 | $udp_watcher->keepalive (0); |
|
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259 | |
|
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260 | WATCHER TYPES |
|
|
261 | Each of the following subsections describes a single watcher type. |
|
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262 | |
|
|
263 | I/O WATCHERS - is this file descriptor readable or writable? |
170 | $w = EV::io $fileno_or_fh, $eventmask, $callback |
264 | $w = EV::io $fileno_or_fh, $eventmask, $callback |
171 | $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
265 | $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
172 | As long as the returned watcher object is alive, call the $callback |
266 | As long as the returned watcher object is alive, call the $callback |
173 | when the events specified in $eventmask. |
267 | when at least one of events specified in $eventmask occurs. |
174 | |
268 | |
175 | The $eventmask can be one or more of these constants ORed together: |
269 | The $eventmask can be one or more of these constants ORed together: |
176 | |
270 | |
177 | EV::READ wait until read() wouldn't block anymore |
271 | EV::READ wait until read() wouldn't block anymore |
178 | EV::WRITE wait until write() wouldn't block anymore |
272 | EV::WRITE wait until write() wouldn't block anymore |
… | |
… | |
190 | |
284 | |
191 | $current_eventmask = $w->events |
285 | $current_eventmask = $w->events |
192 | $old_eventmask = $w->events ($new_eventmask) |
286 | $old_eventmask = $w->events ($new_eventmask) |
193 | Returns the previously set event mask and optionally set a new one. |
287 | Returns the previously set event mask and optionally set a new one. |
194 | |
288 | |
|
|
289 | TIMER WATCHERS - relative and optionally repeating timeouts |
195 | $w = EV::timer $after, $repeat, $callback |
290 | $w = EV::timer $after, $repeat, $callback |
196 | $w = EV::timer_ns $after, $repeat, $callback |
291 | $w = EV::timer_ns $after, $repeat, $callback |
197 | Calls the callback after $after seconds. If $repeat is non-zero, the |
292 | Calls the callback after $after seconds (which may be fractional). |
198 | timer will be restarted (with the $repeat value as $after) after the |
293 | If $repeat is non-zero, the timer will be restarted (with the |
199 | callback returns. |
294 | $repeat value as $after) after the callback returns. |
200 | |
295 | |
201 | This means that the callback would be called roughly after $after |
296 | This means that the callback would be called roughly after $after |
202 | seconds, and then every $repeat seconds. "Roughly" because the time |
297 | seconds, and then every $repeat seconds. The timer does his best not |
203 | of callback processing is not taken into account, so the timer will |
298 | to drift, but it will not invoke the timer more often then once per |
204 | slowly drift. If that isn't acceptable, look at EV::periodic. |
299 | event loop iteration, and might drift in other cases. If that isn't |
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300 | acceptable, look at EV::periodic, which can provide long-term stable |
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301 | timers. |
205 | |
302 | |
206 | The timer is based on a monotonic clock, that is if somebody is |
303 | The timer is based on a monotonic clock, that is, if somebody is |
207 | sitting in front of the machine while the timer is running and |
304 | sitting in front of the machine while the timer is running and |
208 | changes the system clock, the timer will nevertheless run (roughly) |
305 | changes the system clock, the timer will nevertheless run (roughly) |
209 | the same time. |
306 | the same time. |
210 | |
307 | |
211 | The "timer_ns" variant doesn't start (activate) the newly created |
308 | The "timer_ns" variant doesn't start (activate) the newly created |
212 | watcher. |
309 | watcher. |
213 | |
310 | |
214 | $w->set ($after, $repeat) |
311 | $w->set ($after, $repeat) |
215 | Reconfigures the watcher, see the constructor above for details. Can |
312 | Reconfigures the watcher, see the constructor above for details. Can |
216 | be at any time. |
313 | be called at any time. |
217 | |
314 | |
218 | $w->again |
315 | $w->again |
219 | Similar to the "start" method, but has special semantics for |
316 | Similar to the "start" method, but has special semantics for |
220 | repeating timers: |
317 | repeating timers: |
221 | |
318 | |
|
|
319 | If the timer is active and non-repeating, it will be stopped. |
|
|
320 | |
222 | If the timer is active and repeating, reset the timeout to occur |
321 | If the timer is active and repeating, reset the timeout to occur |
223 | $repeat seconds after now. |
322 | $repeat seconds after now. |
224 | |
323 | |
225 | If the timer is active and non-repeating, it will be stopped. |
|
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226 | |
|
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227 | If the timer is in active and repeating, start it. |
324 | If the timer is inactive and repeating, start it using the repeat |
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325 | value. |
228 | |
326 | |
229 | Otherwise do nothing. |
327 | Otherwise do nothing. |
230 | |
328 | |
231 | This behaviour is useful when you have a timeout for some IO |
329 | This behaviour is useful when you have a timeout for some IO |
232 | operation. You create a timer object with the same value for $after |
330 | operation. You create a timer object with the same value for $after |
233 | and $repeat, and then, in the read/write watcher, run the "again" |
331 | and $repeat, and then, in the read/write watcher, run the "again" |
234 | method on the timeout. |
332 | method on the timeout. |
235 | |
333 | |
|
|
334 | PERIODIC WATCHERS - to cron or not to cron? |
236 | $w = EV::periodic $at, $interval, $callback |
335 | $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
237 | $w = EV::periodic_ns $at, $interval, $callback |
336 | $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
238 | Similar to EV::timer, but the time is given as an absolute point in |
337 | Similar to EV::timer, but is not based on relative timeouts but on |
239 | time ($at), plus an optional $interval. |
338 | absolute times. Apart from creating "simple" timers that trigger |
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339 | "at" the specified time, it can also be used for non-drifting |
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340 | absolute timers and more complex, cron-like, setups that are not |
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341 | adversely affected by time jumps (i.e. when the system clock is |
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342 | changed by explicit date -s or other means such as ntpd). It is also |
|
|
343 | the most complex watcher type in EV. |
240 | |
344 | |
241 | If the $interval is zero, then the callback will be called at the |
345 | It has three distinct "modes": |
242 | time $at if that is in the future, or as soon as possible if it is |
|
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243 | in the past. It will not automatically repeat. |
|
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244 | |
346 | |
245 | If the $interval is nonzero, then the watcher will always be |
347 | * absolute timer ($interval = $reschedule_cb = 0) |
246 | scheduled to time out at the next "$at + N * $interval" time. |
348 | This time simply fires at the wallclock time $at and doesn't |
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349 | repeat. It will not adjust when a time jump occurs, that is, if |
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350 | it is to be run at January 1st 2011 then it will run when the |
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351 | system time reaches or surpasses this time. |
247 | |
352 | |
248 | This can be used to schedule a callback to run at very regular |
353 | * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) |
249 | intervals, as long as the processing time is less then the interval |
354 | In this mode the watcher will always be scheduled to time out at |
250 | (otherwise obviously events will be skipped). |
355 | the next "$at + N * $interval" time (for some integer N) and |
|
|
356 | then repeat, regardless of any time jumps. |
251 | |
357 | |
|
|
358 | This can be used to create timers that do not drift with respect |
|
|
359 | to system time: |
|
|
360 | |
|
|
361 | my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; |
|
|
362 | |
|
|
363 | That doesn't mean there will always be 3600 seconds in between |
|
|
364 | triggers, but only that the the clalback will be called when the |
|
|
365 | system time shows a full hour (UTC). |
|
|
366 | |
252 | Another way to think about it (for the mathematically inclined) is |
367 | Another way to think about it (for the mathematically inclined) |
253 | that EV::periodic will try to run the callback at the next possible |
368 | is that EV::periodic will try to run the callback in this mode |
254 | time where "$time = $at (mod $interval)", regardless of any time |
369 | at the next possible time where "$time = $at (mod $interval)", |
255 | jumps. |
370 | regardless of any time jumps. |
256 | |
371 | |
257 | This periodic timer is based on "wallclock time", that is, if the |
372 | * manual reschedule mode ($reschedule_cb = coderef) |
258 | clock changes ("ntp", "date -s" etc.), then the timer will |
373 | In this mode $interval and $at are both being ignored. Instead, |
259 | nevertheless run at the specified time. This means it will never |
374 | each time the periodic watcher gets scheduled, the reschedule |
260 | drift (it might jitter, but it will not drift). |
375 | callback ($reschedule_cb) will be called with the watcher as |
|
|
376 | first, and the current time as second argument. |
|
|
377 | |
|
|
378 | *This callback MUST NOT stop or destroy this or any other |
|
|
379 | periodic watcher, ever*. If you need to stop it, return 1e30 and |
|
|
380 | stop it afterwards. |
|
|
381 | |
|
|
382 | It must return the next time to trigger, based on the passed |
|
|
383 | time value (that is, the lowest time value larger than to the |
|
|
384 | second argument). It will usually be called just before the |
|
|
385 | callback will be triggered, but might be called at other times, |
|
|
386 | too. |
|
|
387 | |
|
|
388 | This can be used to create very complex timers, such as a timer |
|
|
389 | that triggers on each midnight, local time (actually 24 hours |
|
|
390 | after the last midnight, to keep the example simple. If you know |
|
|
391 | a way to do it correctly in about the same space (without |
|
|
392 | requiring elaborate modules), drop me a note :): |
|
|
393 | |
|
|
394 | my $daily = EV::periodic 0, 0, sub { |
|
|
395 | my ($w, $now) = @_; |
|
|
396 | |
|
|
397 | use Time::Local (); |
|
|
398 | my (undef, undef, undef, $d, $m, $y) = localtime $now; |
|
|
399 | 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y |
|
|
400 | }, sub { |
|
|
401 | print "it's midnight or likely shortly after, now\n"; |
|
|
402 | }; |
261 | |
403 | |
262 | The "periodic_ns" variant doesn't start (activate) the newly created |
404 | The "periodic_ns" variant doesn't start (activate) the newly created |
263 | watcher. |
405 | watcher. |
264 | |
406 | |
265 | $w->set ($at, $interval) |
407 | $w->set ($at, $interval, $reschedule_cb) |
266 | Reconfigures the watcher, see the constructor above for details. Can |
408 | Reconfigures the watcher, see the constructor above for details. Can |
267 | be at any time. |
409 | be called at any time. |
268 | |
410 | |
|
|
411 | $w->again |
|
|
412 | Simply stops and starts the watcher again. |
|
|
413 | |
|
|
414 | SIGNAL WATCHERS - signal me when a signal gets signalled! |
269 | $w = EV::signal $signal, $callback |
415 | $w = EV::signal $signal, $callback |
270 | $w = EV::signal_ns $signal, $callback |
416 | $w = EV::signal_ns $signal, $callback |
271 | Call the callback when $signal is received (the signal can be |
417 | Call the callback when $signal is received (the signal can be |
272 | specified by number or by name, just as with kill or %SIG). |
418 | specified by number or by name, just as with "kill" or %SIG). |
273 | |
419 | |
274 | EV will grab the signal for the process (the kernel only allows one |
420 | EV will grab the signal for the process (the kernel only allows one |
275 | component to receive a signal at a time) when you start a signal |
421 | component to receive a signal at a time) when you start a signal |
276 | watcher, and removes it again when you stop it. Perl does the same |
422 | watcher, and removes it again when you stop it. Perl does the same |
277 | when you add/remove callbacks to %SIG, so watch out. |
423 | when you add/remove callbacks to %SIG, so watch out. |
… | |
… | |
281 | The "signal_ns" variant doesn't start (activate) the newly created |
427 | The "signal_ns" variant doesn't start (activate) the newly created |
282 | watcher. |
428 | watcher. |
283 | |
429 | |
284 | $w->set ($signal) |
430 | $w->set ($signal) |
285 | Reconfigures the watcher, see the constructor above for details. Can |
431 | Reconfigures the watcher, see the constructor above for details. Can |
286 | be at any time. |
432 | be called at any time. |
287 | |
433 | |
288 | $current_signum = $w->signal |
434 | $current_signum = $w->signal |
289 | $old_signum = $w->signal ($new_signal) |
435 | $old_signum = $w->signal ($new_signal) |
290 | Returns the previously set signal (always as a number not name) and |
436 | Returns the previously set signal (always as a number not name) and |
291 | optionally set a new one. |
437 | optionally set a new one. |
292 | |
438 | |
|
|
439 | CHILD WATCHERS - watch out for process status changes |
293 | $w = EV::child $pid, $callback |
440 | $w = EV::child $pid, $callback |
294 | $w = EV::child_ns $pid, $callback |
441 | $w = EV::child_ns $pid, $callback |
295 | Call the callback when a status change for pid $pid (or any pid if |
442 | Call the callback when a status change for pid $pid (or any pid if |
296 | $pid is 0) has been received. More precisely: when the process |
443 | $pid is 0) has been received. More precisely: when the process |
297 | receives a SIGCHLD, EV will fetch the outstanding exit/wait status |
444 | receives a "SIGCHLD", EV will fetch the outstanding exit/wait status |
298 | for all changed/zombie children and call the callback. |
445 | for all changed/zombie children and call the callback. |
299 | |
446 | |
300 | You can access both status and pid by using the "rstatus" and "rpid" |
447 | It is valid (and fully supported) to install a child watcher after a |
|
|
448 | child has exited but before the event loop has started its next |
|
|
449 | iteration (for example, first you "fork", then the new child process |
|
|
450 | might exit, and only then do you install a child watcher in the |
|
|
451 | parent for the new pid). |
|
|
452 | |
|
|
453 | You can access both exit (or tracing) status and pid by using the |
301 | methods on the watcher object. |
454 | "rstatus" and "rpid" methods on the watcher object. |
302 | |
455 | |
303 | You can have as many pid watchers per pid as you want. |
456 | You can have as many pid watchers per pid as you want, they will all |
|
|
457 | be called. |
304 | |
458 | |
305 | The "child_ns" variant doesn't start (activate) the newly created |
459 | The "child_ns" variant doesn't start (activate) the newly created |
306 | watcher. |
460 | watcher. |
307 | |
461 | |
308 | $w->set ($pid) |
462 | $w->set ($pid) |
309 | Reconfigures the watcher, see the constructor above for details. Can |
463 | Reconfigures the watcher, see the constructor above for details. Can |
310 | be at any time. |
464 | be called at any time. |
311 | |
465 | |
312 | $current_pid = $w->pid |
466 | $current_pid = $w->pid |
313 | $old_pid = $w->pid ($new_pid) |
467 | $old_pid = $w->pid ($new_pid) |
314 | Returns the previously set process id and optionally set a new one. |
468 | Returns the previously set process id and optionally set a new one. |
315 | |
469 | |
… | |
… | |
319 | |
473 | |
320 | $pid = $w->rpid |
474 | $pid = $w->rpid |
321 | Return the pid of the awaited child (useful when you have installed |
475 | Return the pid of the awaited child (useful when you have installed |
322 | a watcher for all pids). |
476 | a watcher for all pids). |
323 | |
477 | |
|
|
478 | STAT WATCHERS - did the file attributes just change? |
|
|
479 | $w = EV::stat $path, $interval, $callback |
|
|
480 | $w = EV::stat_ns $path, $interval, $callback |
|
|
481 | Call the callback when a file status change has been detected on |
|
|
482 | $path. The $path does not need to exist, changing from "path exists" |
|
|
483 | to "path does not exist" is a status change like any other. |
|
|
484 | |
|
|
485 | The $interval is a recommended polling interval for systems where |
|
|
486 | OS-supported change notifications don't exist or are not supported. |
|
|
487 | If you use 0 then an unspecified default is used (which is highly |
|
|
488 | recommended!), which is to be expected to be around five seconds |
|
|
489 | usually. |
|
|
490 | |
|
|
491 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
492 | as even with OS-supported change notifications, this can be |
|
|
493 | resource-intensive. |
|
|
494 | |
|
|
495 | The "stat_ns" variant doesn't start (activate) the newly created |
|
|
496 | watcher. |
|
|
497 | |
|
|
498 | ... = $w->stat |
|
|
499 | This call is very similar to the perl "stat" built-in: It stats |
|
|
500 | (using "lstat") the path specified in the watcher and sets perls |
|
|
501 | stat cache (as well as EV's idea of the current stat values) to the |
|
|
502 | values found. |
|
|
503 | |
|
|
504 | In scalar context, a boolean is return indicating success or failure |
|
|
505 | of the stat. In list context, the same 13-value list as with stat is |
|
|
506 | returned (except that the blksize and blocks fields are not |
|
|
507 | reliable). |
|
|
508 | |
|
|
509 | In the case of an error, errno is set to "ENOENT" (regardless of the |
|
|
510 | actual error value) and the "nlink" value is forced to zero (if the |
|
|
511 | stat was successful then nlink is guaranteed to be non-zero). |
|
|
512 | |
|
|
513 | See also the next two entries for more info. |
|
|
514 | |
|
|
515 | ... = $w->attr |
|
|
516 | Just like "$w->stat", but without the initial stat'ing: this returns |
|
|
517 | the values most recently detected by EV. See the next entry for more |
|
|
518 | info. |
|
|
519 | |
|
|
520 | ... = $w->prev |
|
|
521 | Just like "$w->stat", but without the initial stat'ing: this returns |
|
|
522 | the previous set of values, before the change. |
|
|
523 | |
|
|
524 | That is, when the watcher callback is invoked, "$w->prev" will be |
|
|
525 | set to the values found *before* a change was detected, while |
|
|
526 | "$w->attr" returns the values found leading to the change detection. |
|
|
527 | The difference (if any) between "prev" and "attr" is what triggered |
|
|
528 | the callback. |
|
|
529 | |
|
|
530 | If you did something to the filesystem object and do not want to |
|
|
531 | trigger yet another change, you can call "stat" to update EV's idea |
|
|
532 | of what the current attributes are. |
|
|
533 | |
|
|
534 | $w->set ($path, $interval) |
|
|
535 | Reconfigures the watcher, see the constructor above for details. Can |
|
|
536 | be called at any time. |
|
|
537 | |
|
|
538 | $current_path = $w->path |
|
|
539 | $old_path = $w->path ($new_path) |
|
|
540 | Returns the previously set path and optionally set a new one. |
|
|
541 | |
|
|
542 | $current_interval = $w->interval |
|
|
543 | $old_interval = $w->interval ($new_interval) |
|
|
544 | Returns the previously set interval and optionally set a new one. |
|
|
545 | Can be used to query the actual interval used. |
|
|
546 | |
|
|
547 | IDLE WATCHERS - when you've got nothing better to do... |
324 | $w = EV::idle $callback |
548 | $w = EV::idle $callback |
325 | $w = EV::idle_ns $callback |
549 | $w = EV::idle_ns $callback |
326 | Call the callback when there are no pending io, timer/periodic, |
550 | Call the callback when there are no other pending watchers of the |
327 | signal or child events, i.e. when the process is idle. |
551 | same or higher priority (excluding check, prepare and other idle |
|
|
552 | watchers of the same or lower priority, of course). They are called |
|
|
553 | idle watchers because when the watcher is the highest priority |
|
|
554 | pending event in the process, the process is considered to be idle |
|
|
555 | at that priority. |
|
|
556 | |
|
|
557 | If you want a watcher that is only ever called when *no* other |
|
|
558 | events are outstanding you have to set the priority to "EV::MINPRI". |
328 | |
559 | |
329 | The process will not block as long as any idle watchers are active, |
560 | The process will not block as long as any idle watchers are active, |
330 | and they will be called repeatedly until stopped. |
561 | and they will be called repeatedly until stopped. |
331 | |
562 | |
|
|
563 | For example, if you have idle watchers at priority 0 and 1, and an |
|
|
564 | I/O watcher at priority 0, then the idle watcher at priority 1 and |
|
|
565 | the I/O watcher will always run when ready. Only when the idle |
|
|
566 | watcher at priority 1 is stopped and the I/O watcher at priority 0 |
|
|
567 | is not pending with the 0-priority idle watcher be invoked. |
|
|
568 | |
332 | The "idle_ns" variant doesn't start (activate) the newly created |
569 | The "idle_ns" variant doesn't start (activate) the newly created |
333 | watcher. |
570 | watcher. |
334 | |
571 | |
|
|
572 | PREPARE WATCHERS - customise your event loop! |
335 | $w = EV::prepare $callback |
573 | $w = EV::prepare $callback |
336 | $w = EV::prepare_ns $callback |
574 | $w = EV::prepare_ns $callback |
337 | Call the callback just before the process would block. You can still |
575 | Call the callback just before the process would block. You can still |
338 | create/modify any watchers at this point. |
576 | create/modify any watchers at this point. |
339 | |
577 | |
340 | See the EV::check watcher, below, for explanations and an example. |
578 | See the EV::check watcher, below, for explanations and an example. |
341 | |
579 | |
342 | The "prepare_ns" variant doesn't start (activate) the newly created |
580 | The "prepare_ns" variant doesn't start (activate) the newly created |
343 | watcher. |
581 | watcher. |
344 | |
582 | |
|
|
583 | CHECK WATCHERS - customise your event loop even more! |
345 | $w = EV::check $callback |
584 | $w = EV::check $callback |
346 | $w = EV::check_ns $callback |
585 | $w = EV::check_ns $callback |
347 | Call the callback just after the process wakes up again (after it |
586 | Call the callback just after the process wakes up again (after it |
348 | has gathered events), but before any other callbacks have been |
587 | has gathered events), but before any other callbacks have been |
349 | invoked. |
588 | invoked. |
… | |
… | |
360 | # do nothing unless active |
599 | # do nothing unless active |
361 | $dispatcher->{_event_queue_h} |
600 | $dispatcher->{_event_queue_h} |
362 | or return; |
601 | or return; |
363 | |
602 | |
364 | # make the dispatcher handle any outstanding stuff |
603 | # make the dispatcher handle any outstanding stuff |
|
|
604 | ... not shown |
365 | |
605 | |
366 | # create an IO watcher for each and every socket |
606 | # create an I/O watcher for each and every socket |
367 | @snmp_watcher = ( |
607 | @snmp_watcher = ( |
368 | (map { EV::io $_, EV::READ, sub { } } |
608 | (map { EV::io $_, EV::READ, sub { } } |
369 | keys %{ $dispatcher->{_descriptors} }), |
609 | keys %{ $dispatcher->{_descriptors} }), |
|
|
610 | |
|
|
611 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
|
|
612 | ? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0), |
|
|
613 | 0, sub { }, |
370 | ); |
614 | ); |
371 | |
|
|
372 | # if there are any timeouts, also create a timer |
|
|
373 | push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { } |
|
|
374 | if $event->[Net::SNMP::Dispatcher::_ACTIVE]; |
|
|
375 | }; |
615 | }; |
376 | |
616 | |
377 | The callbacks are irrelevant, the only purpose of those watchers is |
617 | The callbacks are irrelevant (and are not even being called), the |
378 | to wake up the process as soon as one of those events occurs (socket |
618 | only purpose of those watchers is to wake up the process as soon as |
379 | readable, or timer timed out). The corresponding EV::check watcher |
619 | one of those events occurs (socket readable, or timer timed out). |
380 | will then clean up: |
620 | The corresponding EV::check watcher will then clean up: |
381 | |
621 | |
382 | our $snmp_check = EV::check sub { |
622 | our $snmp_check = EV::check sub { |
383 | # destroy all watchers |
623 | # destroy all watchers |
384 | @snmp_watcher = (); |
624 | @snmp_watcher = (); |
385 | |
625 | |
386 | # make the dispatcher handle any new stuff |
626 | # make the dispatcher handle any new stuff |
|
|
627 | ... not shown |
387 | }; |
628 | }; |
388 | |
629 | |
389 | The callbacks of the created watchers will not be called as the |
630 | The callbacks of the created watchers will not be called as the |
390 | watchers are destroyed before this cna happen (remember EV::check |
631 | watchers are destroyed before this cna happen (remember EV::check |
391 | gets called first). |
632 | gets called first). |
392 | |
633 | |
393 | The "check_ns" variant doesn't start (activate) the newly created |
634 | The "check_ns" variant doesn't start (activate) the newly created |
394 | watcher. |
635 | watcher. |
395 | |
636 | |
|
|
637 | FORK WATCHERS - the audacity to resume the event loop after a fork |
|
|
638 | Fork watchers are called when a "fork ()" was detected. The invocation |
|
|
639 | is done before the event loop blocks next and before "check" watchers |
|
|
640 | are being called, and only in the child after the fork. |
|
|
641 | |
|
|
642 | $w = EV::fork $callback |
|
|
643 | $w = EV::fork_ns $callback |
|
|
644 | Call the callback before the event loop is resumed in the child |
|
|
645 | process after a fork. |
|
|
646 | |
|
|
647 | The "fork_ns" variant doesn't start (activate) the newly created |
|
|
648 | watcher. |
|
|
649 | |
|
|
650 | PERL SIGNALS |
|
|
651 | While Perl signal handling (%SIG) is not affected by EV, the behaviour |
|
|
652 | with EV is as the same as any other C library: Perl-signals will only be |
|
|
653 | handled when Perl runs, which means your signal handler might be invoked |
|
|
654 | only the next time an event callback is invoked. |
|
|
655 | |
|
|
656 | The solution is to use EV signal watchers (see "EV::signal"), which will |
|
|
657 | ensure proper operations with regards to other event watchers. |
|
|
658 | |
|
|
659 | If you cannot do this for whatever reason, you can also force a watcher |
|
|
660 | to be called on every event loop iteration by installing a "EV::check" |
|
|
661 | watcher: |
|
|
662 | |
|
|
663 | my $async_check = EV::check sub { }; |
|
|
664 | |
|
|
665 | This ensures that perl shortly gets into control for a short time, and |
|
|
666 | also ensures slower overall operation. |
|
|
667 | |
396 | THREADS |
668 | THREADS |
397 | Threads are not supported by this in any way. Perl pseudo-threads is |
669 | Threads are not supported by this module in any way. Perl pseudo-threads |
398 | evil stuff and must die. |
670 | is evil stuff and must die. As soon as Perl gains real threads I will |
|
|
671 | work on thread support for it. |
|
|
672 | |
|
|
673 | FORK |
|
|
674 | Most of the "improved" event delivering mechanisms of modern operating |
|
|
675 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
|
|
676 | not supported and usually destructive). Libev makes it possible to work |
|
|
677 | around this by having a function that recreates the kernel state after |
|
|
678 | fork in the child. |
|
|
679 | |
|
|
680 | On non-win32 platforms, this module requires the pthread_atfork |
|
|
681 | functionality to do this automatically for you. This function is quite |
|
|
682 | buggy on most BSDs, though, so YMMV. The overhead for this is quite |
|
|
683 | negligible, because everything the function currently does is set a flag |
|
|
684 | that is checked only when the event loop gets used the next time, so |
|
|
685 | when you do fork but not use EV, the overhead is minimal. |
|
|
686 | |
|
|
687 | On win32, there is no notion of fork so all this doesn't apply, of |
|
|
688 | course. |
399 | |
689 | |
400 | SEE ALSO |
690 | SEE ALSO |
401 | L<EV::DNS>, L<EV::AnyEvent>. |
691 | EV::ADNS (asynchronous dns), Glib::EV (makes Glib/Gtk2 use EV as event |
|
|
692 | loop), Coro::EV (efficient coroutines with EV). |
402 | |
693 | |
403 | AUTHOR |
694 | AUTHOR |
404 | Marc Lehmann <schmorp@schmorp.de> |
695 | Marc Lehmann <schmorp@schmorp.de> |
405 | http://home.schmorp.de/ |
696 | http://home.schmorp.de/ |
406 | |
697 | |