… | |
… | |
38 | |
38 | |
39 | my $w = EV::child 666, sub { |
39 | my $w = EV::child 666, sub { |
40 | my ($w, $revents) = @_; |
40 | my ($w, $revents) = @_; |
41 | my $status = $w->rstatus; |
41 | my $status = $w->rstatus; |
42 | }; |
42 | }; |
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43 | |
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44 | # STAT CHANGES |
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45 | my $w = EV::stat "/etc/passwd", 10, sub { |
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46 | my ($w, $revents) = @_; |
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47 | warn $w->path, " has changed somehow.\n"; |
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48 | }; |
43 | |
49 | |
44 | # MAINLOOP |
50 | # MAINLOOP |
45 | EV::loop; # loop until EV::loop_done is called or all watchers stop |
51 | EV::loop; # loop until EV::unloop is called or all watchers stop |
46 | EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled |
52 | EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled |
47 | EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block |
53 | EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block |
48 | |
54 | |
49 | DESCRIPTION |
55 | DESCRIPTION |
50 | This module provides an interface to libev |
56 | This module provides an interface to libev |
51 | (<http://software.schmorp.de/pkg/libev.html>). |
57 | (<http://software.schmorp.de/pkg/libev.html>). While the documentation |
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58 | below is comprehensive, one might also consult the documentation of |
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59 | libev itself (<http://cvs.schmorp.de/libev/ev.html>) for more subtle |
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60 | details on watcher semantics or some discussion on the available |
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61 | backends, or how to force a specific backend with "LIBEV_FLAGS", or just |
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62 | about in any case because it has much more detailed information. |
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63 | |
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64 | EVENT LOOPS |
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65 | EV supports multiple event loops: There is a single "default event loop" |
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66 | that can handle everything including signals and child watchers, and any |
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67 | number of "dynamic event loops" that can use different backends (with |
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68 | various limitations), but no child and signal watchers. |
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69 | |
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70 | You do not have to do anything to create the default event loop: When |
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71 | the module is loaded a suitable backend is selected on the premise of |
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72 | selecting a working backend (which for example rules out kqueue on most |
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73 | BSDs). Modules should, unless they have "special needs" always use the |
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74 | default loop as this is fastest (perl-wise), best supported by other |
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75 | modules (e.g. AnyEvent or Coro) and most portable event loop. |
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76 | |
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77 | For specific programs you cna create additional event loops dynamically. |
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78 | |
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79 | $loop = new EV::loop [$flags] |
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80 | Create a new event loop as per the specified flags. Please refer to |
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81 | the "ev_loop_new ()" function description in the libev documentation |
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82 | (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI |
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83 | ONS>) for more info. |
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84 | |
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85 | The loop will automatically be destroyed when it is no longer |
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86 | referenced by any watcher and the loop object goes out of scope. |
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87 | |
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88 | Using "EV::FLAG_FORKCHECK" is recommended, as only the default event |
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89 | loop is protected by this module. |
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90 | |
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91 | $loop->loop_fork |
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92 | Must be called after a fork in the child, before entering or |
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93 | continuing the event loop. An alternative is to use |
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94 | "EV::FLAG_FORKCHECK" which calls this fucntion automatically, at |
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95 | some performance loss (refer to the libev documentation). |
52 | |
96 | |
53 | BASIC INTERFACE |
97 | BASIC INTERFACE |
54 | $EV::DIED |
98 | $EV::DIED |
55 | Must contain a reference to a function that is called when a |
99 | Must contain a reference to a function that is called when a |
56 | callback throws an exception (with $@ containing thr error). The |
100 | callback throws an exception (with $@ containing the error). The |
57 | default prints an informative message and continues. |
101 | default prints an informative message and continues. |
58 | |
102 | |
59 | If this callback throws an exception it will be silently ignored. |
103 | If this callback throws an exception it will be silently ignored. |
60 | |
104 | |
61 | $time = EV::time |
105 | $time = EV::time |
62 | Returns the current time in (fractional) seconds since the epoch. |
106 | Returns the current time in (fractional) seconds since the epoch. |
63 | |
107 | |
64 | $time = EV::now |
108 | $time = EV::now |
|
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109 | $time = $loop->now |
65 | Returns the time the last event loop iteration has been started. |
110 | Returns the time the last event loop iteration has been started. |
66 | This is the time that (relative) timers are based on, and refering |
111 | This is the time that (relative) timers are based on, and refering |
67 | to it is usually faster then calling EV::time. |
112 | to it is usually faster then calling EV::time. |
68 | |
113 | |
69 | $method = EV::ev_method |
114 | $backend = EV::backend |
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115 | $backend = $loop->backend |
70 | Returns an integer describing the backend used by libev |
116 | Returns an integer describing the backend used by libev |
71 | (EV::METHOD_SELECT or EV::METHOD_EPOLL). |
117 | (EV::METHOD_SELECT or EV::METHOD_EPOLL). |
72 | |
118 | |
73 | EV::loop [$flags] |
119 | EV::loop [$flags] |
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120 | $loop->loop ([$flags]) |
74 | Begin checking for events and calling callbacks. It returns when a |
121 | Begin checking for events and calling callbacks. It returns when a |
75 | callback calls EV::loop_done. |
122 | callback calls EV::unloop. |
76 | |
123 | |
77 | The $flags argument can be one of the following: |
124 | The $flags argument can be one of the following: |
78 | |
125 | |
79 | 0 as above |
126 | 0 as above |
80 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
127 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
81 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
128 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
82 | |
129 | |
83 | EV::loop_done [$how] |
130 | EV::unloop [$how] |
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131 | $loop->unloop ([$how]) |
84 | When called with no arguments or an argument of 1, makes the |
132 | When called with no arguments or an argument of EV::UNLOOP_ONE, |
85 | innermost call to EV::loop return. |
133 | makes the innermost call to EV::loop return. |
86 | |
134 | |
87 | When called with an agrument of 2, all calls to EV::loop will return |
135 | When called with an argument of EV::UNLOOP_ALL, all calls to |
88 | as fast as possible. |
136 | EV::loop will return as fast as possible. |
89 | |
137 | |
90 | WATCHER |
138 | $count = EV::loop_count |
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139 | $count = $loop->loop_count |
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140 | Return the number of times the event loop has polled for new events. |
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141 | Sometiems useful as a generation counter. |
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142 | |
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143 | EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
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144 | $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) |
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145 | This function rolls together an I/O and a timer watcher for a single |
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146 | one-shot event without the need for managing a watcher object. |
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147 | |
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148 | If $fh_or_undef is a filehandle or file descriptor, then $events |
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149 | must be a bitset containing either "EV::READ", "EV::WRITE" or |
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150 | "EV::READ | EV::WRITE", indicating the type of I/O event you want to |
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151 | wait for. If you do not want to wait for some I/O event, specify |
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152 | "undef" for $fh_or_undef and 0 for $events). |
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153 | |
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154 | If timeout is "undef" or negative, then there will be no timeout. |
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155 | Otherwise a EV::timer with this value will be started. |
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156 | |
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157 | When an error occurs or either the timeout or I/O watcher triggers, |
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158 | then the callback will be called with the received event set (in |
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159 | general you can expect it to be a combination of "EV::ERROR", |
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160 | "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). |
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161 | |
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162 | EV::once doesn't return anything: the watchers stay active till |
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163 | either of them triggers, then they will be stopped and freed, and |
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164 | the callback invoked. |
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165 | |
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166 | EV::feed_fd_event ($fd, $revents) |
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167 | $loop->feed_fd_event ($fd, $revents) |
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168 | Feed an event on a file descriptor into EV. EV will react to this |
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169 | call as if the readyness notifications specified by $revents (a |
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170 | combination of "EV::READ" and "EV::WRITE") happened on the file |
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171 | descriptor $fd. |
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172 | |
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173 | EV::feed_signal_event ($signal) |
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174 | Feed a signal event into EV. EV will react to this call as if the |
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175 | signal specified by $signal had occured. |
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176 | |
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177 | WATCHER OBJECTS |
91 | A watcher is an object that gets created to record your interest in some |
178 | A watcher is an object that gets created to record your interest in some |
92 | event. For instance, if you want to wait for STDIN to become readable, |
179 | event. For instance, if you want to wait for STDIN to become readable, |
93 | you would create an EV::io watcher for that: |
180 | you would create an EV::io watcher for that: |
94 | |
181 | |
95 | my $watcher = EV::io *STDIN, EV::READ, sub { |
182 | my $watcher = EV::io *STDIN, EV::READ, sub { |
96 | my ($watcher, $revents) = @_; |
183 | my ($watcher, $revents) = @_; |
97 | warn "yeah, STDIN should not be readable without blocking!\n" |
184 | warn "yeah, STDIN should now be readable without blocking!\n" |
98 | }; |
185 | }; |
99 | |
186 | |
100 | All watchers can be active (waiting for events) or inactive (paused). |
187 | All watchers can be active (waiting for events) or inactive (paused). |
101 | Only active watchers will have their callbacks invoked. All callbacks |
188 | Only active watchers will have their callbacks invoked. All callbacks |
102 | will be called with at least two arguments: the watcher and a bitmask of |
189 | will be called with at least two arguments: the watcher and a bitmask of |
103 | received events. |
190 | received events. |
104 | |
191 | |
105 | Each watcher type has its associated bit in revents, so you can use the |
192 | Each watcher type has its associated bit in revents, so you can use the |
106 | same callback for multiple watchers. The event mask is named after the |
193 | same callback for multiple watchers. The event mask is named after the |
107 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
194 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
108 | EV::periodic sets EV::PERIODIC and so on, with the exception of IO |
195 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O |
109 | events (which can set both EV::READ and EV::WRITE bits), and EV::timer |
196 | events (which can set both EV::READ and EV::WRITE bits), and EV::timer |
110 | (which uses EV::TIMEOUT). |
197 | (which uses EV::TIMEOUT). |
111 | |
198 | |
112 | In the rare case where one wants to create a watcher but not start it at |
199 | In the rare case where one wants to create a watcher but not start it at |
113 | the same time, each constructor has a variant with a trailing "_ns" in |
200 | the same time, each constructor has a variant with a trailing "_ns" in |
… | |
… | |
119 | |
206 | |
120 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
207 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
121 | ->fh and so on) automatically stop and start it again if it is active, |
208 | ->fh and so on) automatically stop and start it again if it is active, |
122 | which means pending events get lost. |
209 | which means pending events get lost. |
123 | |
210 | |
124 | WATCHER TYPES |
211 | COMMON WATCHER METHODS |
125 | Now lets move to the existing watcher types and asociated methods. |
212 | This section lists methods common to all watchers. |
126 | |
|
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127 | The following methods are available for all watchers. Then followes a |
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128 | description of each watcher constructor (EV::io, EV::timer, |
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129 | EV::periodic, EV::signal, EV::child, EV::idle, EV::prepare and |
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130 | EV::check), followed by any type-specific methods (if any). |
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131 | |
213 | |
132 | $w->start |
214 | $w->start |
133 | Starts a watcher if it isn't active already. Does nothing to an |
215 | Starts a watcher if it isn't active already. Does nothing to an |
134 | already active watcher. By default, all watchers start out in the |
216 | already active watcher. By default, all watchers start out in the |
135 | active state (see the description of the "_ns" variants if you need |
217 | active state (see the description of the "_ns" variants if you need |
136 | stopped watchers). |
218 | stopped watchers). |
137 | |
219 | |
138 | $w->stop |
220 | $w->stop |
139 | Stop a watcher if it is active. Also clear any pending events |
221 | Stop a watcher if it is active. Also clear any pending events |
140 | (events that have been received but that didn't yet result in a |
222 | (events that have been received but that didn't yet result in a |
141 | callback invocation), regardless of wether the watcher was active or |
223 | callback invocation), regardless of whether the watcher was active |
142 | not. |
224 | or not. |
143 | |
225 | |
144 | $bool = $w->is_active |
226 | $bool = $w->is_active |
145 | Returns true if the watcher is active, false otherwise. |
227 | Returns true if the watcher is active, false otherwise. |
146 | |
228 | |
147 | $current_data = $w->data |
229 | $current_data = $w->data |
… | |
… | |
165 | Pending watchers with higher priority will be invoked first. The |
247 | Pending watchers with higher priority will be invoked first. The |
166 | valid range of priorities lies between EV::MAXPRI (default 2) and |
248 | valid range of priorities lies between EV::MAXPRI (default 2) and |
167 | EV::MINPRI (default -2). If the priority is outside this range it |
249 | EV::MINPRI (default -2). If the priority is outside this range it |
168 | will automatically be normalised to the nearest valid priority. |
250 | will automatically be normalised to the nearest valid priority. |
169 | |
251 | |
170 | The default priority of any newly-created weatcher is 0. |
252 | The default priority of any newly-created watcher is 0. |
171 | |
253 | |
|
|
254 | Note that the priority semantics have not yet been fleshed out and |
|
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255 | are subject to almost certain change. |
|
|
256 | |
172 | $w->trigger ($revents) |
257 | $w->invoke ($revents) |
173 | Call the callback *now* with the given event mask. |
258 | Call the callback *now* with the given event mask. |
174 | |
259 | |
|
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260 | $w->feed_event ($revents) |
|
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261 | Feed some events on this watcher into EV. EV will react to this call |
|
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262 | as if the watcher had received the given $revents mask. |
|
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263 | |
|
|
264 | $revents = $w->clear_pending |
|
|
265 | If the watcher is pending, this function clears its pending status |
|
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266 | and returns its $revents bitset (as if its callback was invoked). If |
|
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267 | the watcher isn't pending it does nothing and returns 0. |
|
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268 | |
|
|
269 | $previous_state = $w->keepalive ($bool) |
|
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270 | Normally, "EV::loop" will return when there are no active watchers |
|
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271 | (which is a "deadlock" because no progress can be made anymore). |
|
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272 | This is convinient because it allows you to start your watchers (and |
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273 | your jobs), call "EV::loop" once and when it returns you know that |
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274 | all your jobs are finished (or they forgot to register some watchers |
|
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275 | for their task :). |
|
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276 | |
|
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277 | Sometimes, however, this gets in your way, for example when the |
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278 | module that calls "EV::loop" (usually the main program) is not the |
|
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279 | same module as a long-living watcher (for example a DNS client |
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280 | module written by somebody else even). Then you might want any |
|
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281 | outstanding requests to be handled, but you would not want to keep |
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282 | "EV::loop" from returning just because you happen to have this |
|
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283 | long-running UDP port watcher. |
|
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284 | |
|
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285 | In this case you can clear the keepalive status, which means that |
|
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286 | even though your watcher is active, it won't keep "EV::loop" from |
|
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287 | returning. |
|
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288 | |
|
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289 | The initial value for keepalive is true (enabled), and you cna |
|
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290 | change it any time. |
|
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291 | |
|
|
292 | Example: Register an I/O watcher for some UDP socket but do not keep |
|
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293 | the event loop from running just because of that watcher. |
|
|
294 | |
|
|
295 | my $udp_socket = ... |
|
|
296 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
|
|
297 | $1000udp_watcher->keepalive (0); |
|
|
298 | |
|
|
299 | $loop = $w->loop |
|
|
300 | Return the loop that this watcher is attached to. |
|
|
301 | |
|
|
302 | WATCHER TYPES |
|
|
303 | Each of the following subsections describes a single watcher type. |
|
|
304 | |
|
|
305 | I/O WATCHERS - is this file descriptor readable or writable? |
175 | $w = EV::io $fileno_or_fh, $eventmask, $callback |
306 | $w = EV::io $fileno_or_fh, $eventmask, $callback |
176 | $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
307 | $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
|
|
308 | $w = $loop->io ($fileno_or_fh, $eventmask, $callback) |
|
|
309 | $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback) |
177 | As long as the returned watcher object is alive, call the $callback |
310 | As long as the returned watcher object is alive, call the $callback |
178 | when the events specified in $eventmask. |
311 | when at least one of events specified in $eventmask occurs. |
179 | |
312 | |
180 | The $eventmask can be one or more of these constants ORed together: |
313 | The $eventmask can be one or more of these constants ORed together: |
181 | |
314 | |
182 | EV::READ wait until read() wouldn't block anymore |
315 | EV::READ wait until read() wouldn't block anymore |
183 | EV::WRITE wait until write() wouldn't block anymore |
316 | EV::WRITE wait until write() wouldn't block anymore |
… | |
… | |
195 | |
328 | |
196 | $current_eventmask = $w->events |
329 | $current_eventmask = $w->events |
197 | $old_eventmask = $w->events ($new_eventmask) |
330 | $old_eventmask = $w->events ($new_eventmask) |
198 | Returns the previously set event mask and optionally set a new one. |
331 | Returns the previously set event mask and optionally set a new one. |
199 | |
332 | |
|
|
333 | TIMER WATCHERS - relative and optionally repeating timeouts |
200 | $w = EV::timer $after, $repeat, $callback |
334 | $w = EV::timer $after, $repeat, $callback |
201 | $w = EV::timer_ns $after, $repeat, $callback |
335 | $w = EV::timer_ns $after, $repeat, $callback |
202 | Calls the callback after $after seconds. If $repeat is non-zero, the |
336 | $w = $loop->timer ($after, $repeat, $callback) |
203 | timer will be restarted (with the $repeat value as $after) after the |
337 | $w = $loop->timer_ns ($after, $repeat, $callback) |
204 | callback returns. |
338 | Calls the callback after $after seconds (which may be fractional). |
|
|
339 | If $repeat is non-zero, the timer will be restarted (with the |
|
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340 | $repeat value as $after) after the callback returns. |
205 | |
341 | |
206 | This means that the callback would be called roughly after $after |
342 | This means that the callback would be called roughly after $after |
207 | seconds, and then every $repeat seconds. "Roughly" because the time |
343 | seconds, and then every $repeat seconds. The timer does his best not |
208 | of callback processing is not taken into account, so the timer will |
344 | to drift, but it will not invoke the timer more often then once per |
209 | slowly drift. If that isn't acceptable, look at EV::periodic. |
345 | event loop iteration, and might drift in other cases. If that isn't |
|
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346 | acceptable, look at EV::periodic, which can provide long-term stable |
|
|
347 | timers. |
210 | |
348 | |
211 | The timer is based on a monotonic clock, that is if somebody is |
349 | The timer is based on a monotonic clock, that is, if somebody is |
212 | sitting in front of the machine while the timer is running and |
350 | sitting in front of the machine while the timer is running and |
213 | changes the system clock, the timer will nevertheless run (roughly) |
351 | changes the system clock, the timer will nevertheless run (roughly) |
214 | the same time. |
352 | the same time. |
215 | |
353 | |
216 | The "timer_ns" variant doesn't start (activate) the newly created |
354 | The "timer_ns" variant doesn't start (activate) the newly created |
217 | watcher. |
355 | watcher. |
218 | |
356 | |
219 | $w->set ($after, $repeat) |
357 | $w->set ($after, $repeat) |
220 | Reconfigures the watcher, see the constructor above for details. Can |
358 | Reconfigures the watcher, see the constructor above for details. Can |
221 | be at any time. |
359 | be called at any time. |
222 | |
360 | |
223 | $w->again |
361 | $w->again |
224 | Similar to the "start" method, but has special semantics for |
362 | Similar to the "start" method, but has special semantics for |
225 | repeating timers: |
363 | repeating timers: |
226 | |
364 | |
|
|
365 | If the timer is active and non-repeating, it will be stopped. |
|
|
366 | |
227 | If the timer is active and repeating, reset the timeout to occur |
367 | If the timer is active and repeating, reset the timeout to occur |
228 | $repeat seconds after now. |
368 | $repeat seconds after now. |
229 | |
369 | |
230 | If the timer is active and non-repeating, it will be stopped. |
|
|
231 | |
|
|
232 | If the timer is in active and repeating, start it. |
370 | If the timer is inactive and repeating, start it using the repeat |
|
|
371 | value. |
233 | |
372 | |
234 | Otherwise do nothing. |
373 | Otherwise do nothing. |
235 | |
374 | |
236 | This behaviour is useful when you have a timeout for some IO |
375 | This behaviour is useful when you have a timeout for some IO |
237 | operation. You create a timer object with the same value for $after |
376 | operation. You create a timer object with the same value for $after |
238 | and $repeat, and then, in the read/write watcher, run the "again" |
377 | and $repeat, and then, in the read/write watcher, run the "again" |
239 | method on the timeout. |
378 | method on the timeout. |
240 | |
379 | |
|
|
380 | PERIODIC WATCHERS - to cron or not to cron? |
241 | $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
381 | $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
242 | $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
382 | $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
|
|
383 | $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback) |
|
|
384 | $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback) |
243 | Similar to EV::timer, but is not based on relative timeouts but on |
385 | Similar to EV::timer, but is not based on relative timeouts but on |
244 | absolute times. Apart from creating "simple" timers that trigger |
386 | absolute times. Apart from creating "simple" timers that trigger |
245 | "at" the specified time, it can also be used for non-drifting |
387 | "at" the specified time, it can also be used for non-drifting |
246 | absolute timers and more complex, cron-like, setups that are not |
388 | absolute timers and more complex, cron-like, setups that are not |
247 | adversely affected by time jumps (i.e. when the system clock is |
389 | adversely affected by time jumps (i.e. when the system clock is |
… | |
… | |
275 | at the next possible time where "$time = $at (mod $interval)", |
417 | at the next possible time where "$time = $at (mod $interval)", |
276 | regardless of any time jumps. |
418 | regardless of any time jumps. |
277 | |
419 | |
278 | * manual reschedule mode ($reschedule_cb = coderef) |
420 | * manual reschedule mode ($reschedule_cb = coderef) |
279 | In this mode $interval and $at are both being ignored. Instead, |
421 | In this mode $interval and $at are both being ignored. Instead, |
280 | each time the periodic watcher gets scheduled, the first |
422 | each time the periodic watcher gets scheduled, the reschedule |
281 | callback ($reschedule_cb) will be called with the watcher as |
423 | callback ($reschedule_cb) will be called with the watcher as |
282 | first, and the current time as second argument. |
424 | first, and the current time as second argument. |
283 | |
425 | |
284 | *This callback MUST NOT stop or destroy this or any other |
426 | *This callback MUST NOT stop or destroy this or any other |
285 | periodic watcher, ever*. If you need to stop it, return 1e30 and |
427 | periodic watcher, ever*. If you need to stop it, return 1e30 and |
… | |
… | |
310 | The "periodic_ns" variant doesn't start (activate) the newly created |
452 | The "periodic_ns" variant doesn't start (activate) the newly created |
311 | watcher. |
453 | watcher. |
312 | |
454 | |
313 | $w->set ($at, $interval, $reschedule_cb) |
455 | $w->set ($at, $interval, $reschedule_cb) |
314 | Reconfigures the watcher, see the constructor above for details. Can |
456 | Reconfigures the watcher, see the constructor above for details. Can |
315 | be at any time. |
457 | be called at any time. |
316 | |
458 | |
317 | $w->again |
459 | $w->again |
318 | Simply stops and starts the watcher again. |
460 | Simply stops and starts the watcher again. |
319 | |
461 | |
|
|
462 | $time = $w->at |
|
|
463 | Return the time that the watcher is expected to trigger next. |
|
|
464 | |
|
|
465 | SIGNAL WATCHERS - signal me when a signal gets signalled! |
320 | $w = EV::signal $signal, $callback |
466 | $w = EV::signal $signal, $callback |
321 | $w = EV::signal_ns $signal, $callback |
467 | $w = EV::signal_ns $signal, $callback |
322 | Call the callback when $signal is received (the signal can be |
468 | Call the callback when $signal is received (the signal can be |
323 | specified by number or by name, just as with kill or %SIG). |
469 | specified by number or by name, just as with "kill" or %SIG). |
324 | |
470 | |
325 | EV will grab the signal for the process (the kernel only allows one |
471 | EV will grab the signal for the process (the kernel only allows one |
326 | component to receive a signal at a time) when you start a signal |
472 | component to receive a signal at a time) when you start a signal |
327 | watcher, and removes it again when you stop it. Perl does the same |
473 | watcher, and removes it again when you stop it. Perl does the same |
328 | when you add/remove callbacks to %SIG, so watch out. |
474 | when you add/remove callbacks to %SIG, so watch out. |
… | |
… | |
332 | The "signal_ns" variant doesn't start (activate) the newly created |
478 | The "signal_ns" variant doesn't start (activate) the newly created |
333 | watcher. |
479 | watcher. |
334 | |
480 | |
335 | $w->set ($signal) |
481 | $w->set ($signal) |
336 | Reconfigures the watcher, see the constructor above for details. Can |
482 | Reconfigures the watcher, see the constructor above for details. Can |
337 | be at any time. |
483 | be called at any time. |
338 | |
484 | |
339 | $current_signum = $w->signal |
485 | $current_signum = $w->signal |
340 | $old_signum = $w->signal ($new_signal) |
486 | $old_signum = $w->signal ($new_signal) |
341 | Returns the previously set signal (always as a number not name) and |
487 | Returns the previously set signal (always as a number not name) and |
342 | optionally set a new one. |
488 | optionally set a new one. |
343 | |
489 | |
|
|
490 | CHILD WATCHERS - watch out for process status changes |
344 | $w = EV::child $pid, $callback |
491 | $w = EV::child $pid, $callback |
345 | $w = EV::child_ns $pid, $callback |
492 | $w = EV::child_ns $pid, $callback |
|
|
493 | $w = $loop->child ($pid, $callback) |
|
|
494 | $w = $loop->child_ns ($pid, $callback) |
346 | Call the callback when a status change for pid $pid (or any pid if |
495 | Call the callback when a status change for pid $pid (or any pid if |
347 | $pid is 0) has been received. More precisely: when the process |
496 | $pid is 0) has been received. More precisely: when the process |
348 | receives a SIGCHLD, EV will fetch the outstanding exit/wait status |
497 | receives a "SIGCHLD", EV will fetch the outstanding exit/wait status |
349 | for all changed/zombie children and call the callback. |
498 | for all changed/zombie children and call the callback. |
350 | |
499 | |
351 | You can access both status and pid by using the "rstatus" and "rpid" |
500 | It is valid (and fully supported) to install a child watcher after a |
|
|
501 | child has exited but before the event loop has started its next |
|
|
502 | iteration (for example, first you "fork", then the new child process |
|
|
503 | might exit, and only then do you install a child watcher in the |
|
|
504 | parent for the new pid). |
|
|
505 | |
|
|
506 | You can access both exit (or tracing) status and pid by using the |
352 | methods on the watcher object. |
507 | "rstatus" and "rpid" methods on the watcher object. |
353 | |
508 | |
354 | You can have as many pid watchers per pid as you want. |
509 | You can have as many pid watchers per pid as you want, they will all |
|
|
510 | be called. |
355 | |
511 | |
356 | The "child_ns" variant doesn't start (activate) the newly created |
512 | The "child_ns" variant doesn't start (activate) the newly created |
357 | watcher. |
513 | watcher. |
358 | |
514 | |
359 | $w->set ($pid) |
515 | $w->set ($pid) |
360 | Reconfigures the watcher, see the constructor above for details. Can |
516 | Reconfigures the watcher, see the constructor above for details. Can |
361 | be at any time. |
517 | be called at any time. |
362 | |
518 | |
363 | $current_pid = $w->pid |
519 | $current_pid = $w->pid |
364 | $old_pid = $w->pid ($new_pid) |
520 | $old_pid = $w->pid ($new_pid) |
365 | Returns the previously set process id and optionally set a new one. |
521 | Returns the previously set process id and optionally set a new one. |
366 | |
522 | |
… | |
… | |
370 | |
526 | |
371 | $pid = $w->rpid |
527 | $pid = $w->rpid |
372 | Return the pid of the awaited child (useful when you have installed |
528 | Return the pid of the awaited child (useful when you have installed |
373 | a watcher for all pids). |
529 | a watcher for all pids). |
374 | |
530 | |
|
|
531 | STAT WATCHERS - did the file attributes just change? |
|
|
532 | $w = EV::stat $path, $interval, $callback |
|
|
533 | $w = EV::stat_ns $path, $interval, $callback |
|
|
534 | $w = $loop->stat ($path, $interval, $callback) |
|
|
535 | $w = $loop->stat_ns ($path, $interval, $callback) |
|
|
536 | Call the callback when a file status change has been detected on |
|
|
537 | $path. The $path does not need to exist, changing from "path exists" |
|
|
538 | to "path does not exist" is a status change like any other. |
|
|
539 | |
|
|
540 | The $interval is a recommended polling interval for systems where |
|
|
541 | OS-supported change notifications don't exist or are not supported. |
|
|
542 | If you use 0 then an unspecified default is used (which is highly |
|
|
543 | recommended!), which is to be expected to be around five seconds |
|
|
544 | usually. |
|
|
545 | |
|
|
546 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
547 | as even with OS-supported change notifications, this can be |
|
|
548 | resource-intensive. |
|
|
549 | |
|
|
550 | The "stat_ns" variant doesn't start (activate) the newly created |
|
|
551 | watcher. |
|
|
552 | |
|
|
553 | ... = $w->stat |
|
|
554 | This call is very similar to the perl "stat" built-in: It stats |
|
|
555 | (using "lstat") the path specified in the watcher and sets perls |
|
|
556 | stat cache (as well as EV's idea of the current stat values) to the |
|
|
557 | values found. |
|
|
558 | |
|
|
559 | In scalar context, a boolean is return indicating success or failure |
|
|
560 | of the stat. In list context, the same 13-value list as with stat is |
|
|
561 | returned (except that the blksize and blocks fields are not |
|
|
562 | reliable). |
|
|
563 | |
|
|
564 | In the case of an error, errno is set to "ENOENT" (regardless of the |
|
|
565 | actual error value) and the "nlink" value is forced to zero (if the |
|
|
566 | stat was successful then nlink is guaranteed to be non-zero). |
|
|
567 | |
|
|
568 | See also the next two entries for more info. |
|
|
569 | |
|
|
570 | ... = $w->attr |
|
|
571 | Just like "$w->stat", but without the initial stat'ing: this returns |
|
|
572 | the values most recently detected by EV. See the next entry for more |
|
|
573 | info. |
|
|
574 | |
|
|
575 | ... = $w->prev |
|
|
576 | Just like "$w->stat", but without the initial stat'ing: this returns |
|
|
577 | the previous set of values, before the change. |
|
|
578 | |
|
|
579 | That is, when the watcher callback is invoked, "$w->prev" will be |
|
|
580 | set to the values found *before* a change was detected, while |
|
|
581 | "$w->attr" returns the values found leading to the change detection. |
|
|
582 | The difference (if any) between "prev" and "attr" is what triggered |
|
|
583 | the callback. |
|
|
584 | |
|
|
585 | If you did something to the filesystem object and do not want to |
|
|
586 | trigger yet another change, you can call "stat" to update EV's idea |
|
|
587 | of what the current attributes are. |
|
|
588 | |
|
|
589 | $w->set ($path, $interval) |
|
|
590 | Reconfigures the watcher, see the constructor above for details. Can |
|
|
591 | be called at any time. |
|
|
592 | |
|
|
593 | $current_path = $w->path |
|
|
594 | $old_path = $w->path ($new_path) |
|
|
595 | Returns the previously set path and optionally set a new one. |
|
|
596 | |
|
|
597 | $current_interval = $w->interval |
|
|
598 | $old_interval = $w->interval ($new_interval) |
|
|
599 | Returns the previously set interval and optionally set a new one. |
|
|
600 | Can be used to query the actual interval used. |
|
|
601 | |
|
|
602 | IDLE WATCHERS - when you've got nothing better to do... |
375 | $w = EV::idle $callback |
603 | $w = EV::idle $callback |
376 | $w = EV::idle_ns $callback |
604 | $w = EV::idle_ns $callback |
|
|
605 | $w = $loop->idle ($callback) |
|
|
606 | $w = $loop->idle_ns ($callback) |
377 | Call the callback when there are no pending io, timer/periodic, |
607 | Call the callback when there are no other pending watchers of the |
378 | signal or child events, i.e. when the process is idle. |
608 | same or higher priority (excluding check, prepare and other idle |
|
|
609 | watchers of the same or lower priority, of course). They are called |
|
|
610 | idle watchers because when the watcher is the highest priority |
|
|
611 | pending event in the process, the process is considered to be idle |
|
|
612 | at that priority. |
|
|
613 | |
|
|
614 | If you want a watcher that is only ever called when *no* other |
|
|
615 | events are outstanding you have to set the priority to "EV::MINPRI". |
379 | |
616 | |
380 | The process will not block as long as any idle watchers are active, |
617 | The process will not block as long as any idle watchers are active, |
381 | and they will be called repeatedly until stopped. |
618 | and they will be called repeatedly until stopped. |
382 | |
619 | |
|
|
620 | For example, if you have idle watchers at priority 0 and 1, and an |
|
|
621 | I/O watcher at priority 0, then the idle watcher at priority 1 and |
|
|
622 | the I/O watcher will always run when ready. Only when the idle |
|
|
623 | watcher at priority 1 is stopped and the I/O watcher at priority 0 |
|
|
624 | is not pending with the 0-priority idle watcher be invoked. |
|
|
625 | |
383 | The "idle_ns" variant doesn't start (activate) the newly created |
626 | The "idle_ns" variant doesn't start (activate) the newly created |
384 | watcher. |
627 | watcher. |
385 | |
628 | |
|
|
629 | PREPARE WATCHERS - customise your event loop! |
386 | $w = EV::prepare $callback |
630 | $w = EV::prepare $callback |
387 | $w = EV::prepare_ns $callback |
631 | $w = EV::prepare_ns $callback |
|
|
632 | $w = $loop->prepare ($callback) |
|
|
633 | $w = $loop->prepare_ns ($callback) |
388 | Call the callback just before the process would block. You can still |
634 | Call the callback just before the process would block. You can still |
389 | create/modify any watchers at this point. |
635 | create/modify any watchers at this point. |
390 | |
636 | |
391 | See the EV::check watcher, below, for explanations and an example. |
637 | See the EV::check watcher, below, for explanations and an example. |
392 | |
638 | |
393 | The "prepare_ns" variant doesn't start (activate) the newly created |
639 | The "prepare_ns" variant doesn't start (activate) the newly created |
394 | watcher. |
640 | watcher. |
395 | |
641 | |
|
|
642 | CHECK WATCHERS - customise your event loop even more! |
396 | $w = EV::check $callback |
643 | $w = EV::check $callback |
397 | $w = EV::check_ns $callback |
644 | $w = EV::check_ns $callback |
|
|
645 | $w = $loop->check ($callback) |
|
|
646 | $w = $loop->check_ns ($callback) |
398 | Call the callback just after the process wakes up again (after it |
647 | Call the callback just after the process wakes up again (after it |
399 | has gathered events), but before any other callbacks have been |
648 | has gathered events), but before any other callbacks have been |
400 | invoked. |
649 | invoked. |
401 | |
650 | |
402 | This is used to integrate other event-based software into the EV |
651 | This is used to integrate other event-based software into the EV |
… | |
… | |
411 | # do nothing unless active |
660 | # do nothing unless active |
412 | $dispatcher->{_event_queue_h} |
661 | $dispatcher->{_event_queue_h} |
413 | or return; |
662 | or return; |
414 | |
663 | |
415 | # make the dispatcher handle any outstanding stuff |
664 | # make the dispatcher handle any outstanding stuff |
|
|
665 | ... not shown |
416 | |
666 | |
417 | # create an IO watcher for each and every socket |
667 | # create an I/O watcher for each and every socket |
418 | @snmp_watcher = ( |
668 | @snmp_watcher = ( |
419 | (map { EV::io $_, EV::READ, sub { } } |
669 | (map { EV::io $_, EV::READ, sub { } } |
420 | keys %{ $dispatcher->{_descriptors} }), |
670 | keys %{ $dispatcher->{_descriptors} }), |
|
|
671 | |
|
|
672 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
|
|
673 | ? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0), |
|
|
674 | 0, sub { }, |
421 | ); |
675 | ); |
422 | |
|
|
423 | # if there are any timeouts, also create a timer |
|
|
424 | push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { } |
|
|
425 | if $event->[Net::SNMP::Dispatcher::_ACTIVE]; |
|
|
426 | }; |
676 | }; |
427 | |
677 | |
428 | The callbacks are irrelevant, the only purpose of those watchers is |
678 | The callbacks are irrelevant (and are not even being called), the |
429 | to wake up the process as soon as one of those events occurs (socket |
679 | only purpose of those watchers is to wake up the process as soon as |
430 | readable, or timer timed out). The corresponding EV::check watcher |
680 | one of those events occurs (socket readable, or timer timed out). |
431 | will then clean up: |
681 | The corresponding EV::check watcher will then clean up: |
432 | |
682 | |
433 | our $snmp_check = EV::check sub { |
683 | our $snmp_check = EV::check sub { |
434 | # destroy all watchers |
684 | # destroy all watchers |
435 | @snmp_watcher = (); |
685 | @snmp_watcher = (); |
436 | |
686 | |
437 | # make the dispatcher handle any new stuff |
687 | # make the dispatcher handle any new stuff |
|
|
688 | ... not shown |
438 | }; |
689 | }; |
439 | |
690 | |
440 | The callbacks of the created watchers will not be called as the |
691 | The callbacks of the created watchers will not be called as the |
441 | watchers are destroyed before this cna happen (remember EV::check |
692 | watchers are destroyed before this cna happen (remember EV::check |
442 | gets called first). |
693 | gets called first). |
443 | |
694 | |
444 | The "check_ns" variant doesn't start (activate) the newly created |
695 | The "check_ns" variant doesn't start (activate) the newly created |
445 | watcher. |
696 | watcher. |
446 | |
697 | |
|
|
698 | FORK WATCHERS - the audacity to resume the event loop after a fork |
|
|
699 | Fork watchers are called when a "fork ()" was detected. The invocation |
|
|
700 | is done before the event loop blocks next and before "check" watchers |
|
|
701 | are being called, and only in the child after the fork. |
|
|
702 | |
|
|
703 | $w = EV::fork $callback |
|
|
704 | $w = EV::fork_ns $callback |
|
|
705 | $w = $loop->fork ($callback) |
|
|
706 | $w = $loop->fork_ns ($callback) |
|
|
707 | Call the callback before the event loop is resumed in the child |
|
|
708 | process after a fork. |
|
|
709 | |
|
|
710 | The "fork_ns" variant doesn't start (activate) the newly created |
|
|
711 | watcher. |
|
|
712 | |
|
|
713 | PERL SIGNALS |
|
|
714 | While Perl signal handling (%SIG) is not affected by EV, the behaviour |
|
|
715 | with EV is as the same as any other C library: Perl-signals will only be |
|
|
716 | handled when Perl runs, which means your signal handler might be invoked |
|
|
717 | only the next time an event callback is invoked. |
|
|
718 | |
|
|
719 | The solution is to use EV signal watchers (see "EV::signal"), which will |
|
|
720 | ensure proper operations with regards to other event watchers. |
|
|
721 | |
|
|
722 | If you cannot do this for whatever reason, you can also force a watcher |
|
|
723 | to be called on every event loop iteration by installing a "EV::check" |
|
|
724 | watcher: |
|
|
725 | |
|
|
726 | my $async_check = EV::check sub { }; |
|
|
727 | |
|
|
728 | This ensures that perl gets into control for a short time to handle any |
|
|
729 | pending signals, and also ensures (slightly) slower overall operation. |
|
|
730 | |
447 | THREADS |
731 | THREADS |
448 | Threads are not supported by this in any way. Perl pseudo-threads is |
732 | Threads are not supported by this module in any way. Perl pseudo-threads |
449 | evil stuff and must die. |
733 | is evil stuff and must die. As soon as Perl gains real threads I will |
|
|
734 | work on thread support for it. |
|
|
735 | |
|
|
736 | FORK |
|
|
737 | Most of the "improved" event delivering mechanisms of modern operating |
|
|
738 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
|
|
739 | not supported and usually destructive). Libev makes it possible to work |
|
|
740 | around this by having a function that recreates the kernel state after |
|
|
741 | fork in the child. |
|
|
742 | |
|
|
743 | On non-win32 platforms, this module requires the pthread_atfork |
|
|
744 | functionality to do this automatically for you. This function is quite |
|
|
745 | buggy on most BSDs, though, so YMMV. The overhead for this is quite |
|
|
746 | negligible, because everything the function currently does is set a flag |
|
|
747 | that is checked only when the event loop gets used the next time, so |
|
|
748 | when you do fork but not use EV, the overhead is minimal. |
|
|
749 | |
|
|
750 | On win32, there is no notion of fork so all this doesn't apply, of |
|
|
751 | course. |
450 | |
752 | |
451 | SEE ALSO |
753 | SEE ALSO |
452 | L<EV::DNS>, L<EV::AnyEvent>. |
754 | EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event |
|
|
755 | loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines |
|
|
756 | with EV), Net::SNMP::EV (asynchronous SNMP). |
453 | |
757 | |
454 | AUTHOR |
758 | AUTHOR |
455 | Marc Lehmann <schmorp@schmorp.de> |
759 | Marc Lehmann <schmorp@schmorp.de> |
456 | http://home.schmorp.de/ |
760 | http://home.schmorp.de/ |
457 | |
761 | |