1 | => NAME |
1 | NAME |
2 | AnyEvent - provide framework for multiple event loops |
2 | AnyEvent - provide framework for multiple event loops |
3 | |
3 | |
4 | EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event |
4 | EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event |
5 | loops |
5 | loops |
6 | |
6 | |
7 | SYNOPSIS |
7 | SYNOPSIS |
8 | use AnyEvent; |
8 | use AnyEvent; |
9 | |
9 | |
10 | my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { |
10 | my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { ... }); |
11 | ... |
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12 | }); |
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13 | |
11 | |
14 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
12 | my $w = AnyEvent->timer (after => $seconds, cb => sub { ... }); |
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13 | my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ... |
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14 | |
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15 | print AnyEvent->now; # prints current event loop time |
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16 | print AnyEvent->time; # think Time::HiRes::time or simply CORE::time. |
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17 | |
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18 | my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... }); |
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19 | |
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20 | my $w = AnyEvent->child (pid => $pid, cb => sub { |
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21 | my ($pid, $status) = @_; |
15 | ... |
22 | ... |
16 | }); |
23 | }); |
17 | |
24 | |
18 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
25 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
19 | $w->send; # wake up current and all future recv's |
26 | $w->send; # wake up current and all future recv's |
20 | $w->recv; # enters "main loop" till $condvar gets ->send |
27 | $w->recv; # enters "main loop" till $condvar gets ->send |
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28 | # use a condvar in callback mode: |
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29 | $w->cb (sub { $_[0]->recv }); |
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30 | |
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31 | INTRODUCTION/TUTORIAL |
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32 | This manpage is mainly a reference manual. If you are interested in a |
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33 | tutorial or some gentle introduction, have a look at the AnyEvent::Intro |
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34 | manpage. |
21 | |
35 | |
22 | WHY YOU SHOULD USE THIS MODULE (OR NOT) |
36 | WHY YOU SHOULD USE THIS MODULE (OR NOT) |
23 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
37 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
24 | nowadays. So what is different about AnyEvent? |
38 | nowadays. So what is different about AnyEvent? |
25 | |
39 | |
26 | Executive Summary: AnyEvent is *compatible*, AnyEvent is *free of |
40 | Executive Summary: AnyEvent is *compatible*, AnyEvent is *free of |
27 | policy* and AnyEvent is *small and efficient*. |
41 | policy* and AnyEvent is *small and efficient*. |
28 | |
42 | |
29 | First and foremost, *AnyEvent is not an event model* itself, it only |
43 | First and foremost, *AnyEvent is not an event model* itself, it only |
30 | interfaces to whatever event model the main program happens to use in a |
44 | interfaces to whatever event model the main program happens to use, in a |
31 | pragmatic way. For event models and certain classes of immortals alike, |
45 | pragmatic way. For event models and certain classes of immortals alike, |
32 | the statement "there can only be one" is a bitter reality: In general, |
46 | the statement "there can only be one" is a bitter reality: In general, |
33 | only one event loop can be active at the same time in a process. |
47 | only one event loop can be active at the same time in a process. |
34 | AnyEvent helps hiding the differences between those event loops. |
48 | AnyEvent cannot change this, but it can hide the differences between |
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49 | those event loops. |
35 | |
50 | |
36 | The goal of AnyEvent is to offer module authors the ability to do event |
51 | The goal of AnyEvent is to offer module authors the ability to do event |
37 | programming (waiting for I/O or timer events) without subscribing to a |
52 | programming (waiting for I/O or timer events) without subscribing to a |
38 | religion, a way of living, and most importantly: without forcing your |
53 | religion, a way of living, and most importantly: without forcing your |
39 | module users into the same thing by forcing them to use the same event |
54 | module users into the same thing by forcing them to use the same event |
40 | model you use. |
55 | model you use. |
41 | |
56 | |
42 | For modules like POE or IO::Async (which is a total misnomer as it is |
57 | For modules like POE or IO::Async (which is a total misnomer as it is |
43 | actually doing all I/O *synchronously*...), using them in your module is |
58 | actually doing all I/O *synchronously*...), using them in your module is |
44 | like joining a cult: After you joined, you are dependent on them and you |
59 | like joining a cult: After you joined, you are dependent on them and you |
45 | cannot use anything else, as it is simply incompatible to everything |
60 | cannot use anything else, as they are simply incompatible to everything |
46 | that isn't itself. What's worse, all the potential users of your module |
61 | that isn't them. What's worse, all the potential users of your module |
47 | are *also* forced to use the same event loop you use. |
62 | are *also* forced to use the same event loop you use. |
48 | |
63 | |
49 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
64 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
50 | fine. AnyEvent + Tk works fine etc. etc. but none of these work together |
65 | fine. AnyEvent + Tk works fine etc. etc. but none of these work together |
51 | with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if your |
66 | with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if your |
52 | module uses one of those, every user of your module has to use it, too. |
67 | module uses one of those, every user of your module has to use it, too. |
53 | But if your module uses AnyEvent, it works transparently with all event |
68 | But if your module uses AnyEvent, it works transparently with all event |
54 | models it supports (including stuff like POE and IO::Async, as long as |
69 | models it supports (including stuff like IO::Async, as long as those use |
55 | those use one of the supported event loops. It is trivial to add new |
70 | one of the supported event loops. It is trivial to add new event loops |
56 | event loops to AnyEvent, too, so it is future-proof). |
71 | to AnyEvent, too, so it is future-proof). |
57 | |
72 | |
58 | In addition to being free of having to use *the one and only true event |
73 | In addition to being free of having to use *the one and only true event |
59 | model*, AnyEvent also is free of bloat and policy: with POE or similar |
74 | model*, AnyEvent also is free of bloat and policy: with POE or similar |
60 | modules, you get an enormous amount of code and strict rules you have to |
75 | modules, you get an enormous amount of code and strict rules you have to |
61 | follow. AnyEvent, on the other hand, is lean and up to the point, by |
76 | follow. AnyEvent, on the other hand, is lean and up to the point, by |
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128 | Many watchers either are used with "recursion" (repeating timers for |
143 | Many watchers either are used with "recursion" (repeating timers for |
129 | example), or need to refer to their watcher object in other ways. |
144 | example), or need to refer to their watcher object in other ways. |
130 | |
145 | |
131 | An any way to achieve that is this pattern: |
146 | An any way to achieve that is this pattern: |
132 | |
147 | |
133 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
148 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
134 | # you can use $w here, for example to undef it |
149 | # you can use $w here, for example to undef it |
135 | undef $w; |
150 | undef $w; |
136 | }); |
151 | }); |
137 | |
152 | |
138 | Note that "my $w; $w =" combination. This is necessary because in Perl, |
153 | Note that "my $w; $w =" combination. This is necessary because in Perl, |
139 | my variables are only visible after the statement in which they are |
154 | my variables are only visible after the statement in which they are |
140 | declared. |
155 | declared. |
141 | |
156 | |
142 | I/O WATCHERS |
157 | I/O WATCHERS |
143 | You can create an I/O watcher by calling the "AnyEvent->io" method with |
158 | You can create an I/O watcher by calling the "AnyEvent->io" method with |
144 | the following mandatory key-value pairs as arguments: |
159 | the following mandatory key-value pairs as arguments: |
145 | |
160 | |
146 | "fh" the Perl *file handle* (*not* file descriptor) to watch for events. |
161 | "fh" the Perl *file handle* (*not* file descriptor) to watch for events |
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162 | (AnyEvent might or might not keep a reference to this file handle). |
147 | "poll" must be a string that is either "r" or "w", which creates a |
163 | "poll" must be a string that is either "r" or "w", which creates a |
148 | watcher waiting for "r"eadable or "w"ritable events, respectively. "cb" |
164 | watcher waiting for "r"eadable or "w"ritable events, respectively. "cb" |
149 | is the callback to invoke each time the file handle becomes ready. |
165 | is the callback to invoke each time the file handle becomes ready. |
150 | |
166 | |
151 | Although the callback might get passed parameters, their value and |
167 | Although the callback might get passed parameters, their value and |
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158 | |
174 | |
159 | Some event loops issue spurious readyness notifications, so you should |
175 | Some event loops issue spurious readyness notifications, so you should |
160 | always use non-blocking calls when reading/writing from/to your file |
176 | always use non-blocking calls when reading/writing from/to your file |
161 | handles. |
177 | handles. |
162 | |
178 | |
163 | Example: |
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164 | |
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165 | # wait for readability of STDIN, then read a line and disable the watcher |
179 | Example: wait for readability of STDIN, then read a line and disable the |
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180 | watcher. |
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181 | |
166 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
182 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
167 | chomp (my $input = <STDIN>); |
183 | chomp (my $input = <STDIN>); |
168 | warn "read: $input\n"; |
184 | warn "read: $input\n"; |
169 | undef $w; |
185 | undef $w; |
170 | }); |
186 | }); |
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179 | |
195 | |
180 | Although the callback might get passed parameters, their value and |
196 | Although the callback might get passed parameters, their value and |
181 | presence is undefined and you cannot rely on them. Portable AnyEvent |
197 | presence is undefined and you cannot rely on them. Portable AnyEvent |
182 | callbacks cannot use arguments passed to time watcher callbacks. |
198 | callbacks cannot use arguments passed to time watcher callbacks. |
183 | |
199 | |
184 | The timer callback will be invoked at most once: if you want a repeating |
200 | The callback will normally be invoked once only. If you specify another |
185 | timer you have to create a new watcher (this is a limitation by both Tk |
201 | parameter, "interval", as a strictly positive number (> 0), then the |
186 | and Glib). |
202 | callback will be invoked regularly at that interval (in fractional |
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203 | seconds) after the first invocation. If "interval" is specified with a |
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204 | false value, then it is treated as if it were missing. |
187 | |
205 | |
188 | Example: |
206 | The callback will be rescheduled before invoking the callback, but no |
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207 | attempt is done to avoid timer drift in most backends, so the interval |
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208 | is only approximate. |
189 | |
209 | |
190 | # fire an event after 7.7 seconds |
210 | Example: fire an event after 7.7 seconds. |
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211 | |
191 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
212 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
192 | warn "timeout\n"; |
213 | warn "timeout\n"; |
193 | }); |
214 | }); |
194 | |
215 | |
195 | # to cancel the timer: |
216 | # to cancel the timer: |
196 | undef $w; |
217 | undef $w; |
197 | |
218 | |
198 | Example 2: |
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199 | |
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200 | # fire an event after 0.5 seconds, then roughly every second |
219 | Example 2: fire an event after 0.5 seconds, then roughly every second. |
201 | my $w; |
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202 | |
220 | |
203 | my $cb = sub { |
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204 | # cancel the old timer while creating a new one |
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205 | $w = AnyEvent->timer (after => 1, cb => $cb); |
221 | my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub { |
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222 | warn "timeout\n"; |
206 | }; |
223 | }; |
207 | |
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208 | # start the "loop" by creating the first watcher |
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209 | $w = AnyEvent->timer (after => 0.5, cb => $cb); |
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210 | |
224 | |
211 | TIMING ISSUES |
225 | TIMING ISSUES |
212 | There are two ways to handle timers: based on real time (relative, "fire |
226 | There are two ways to handle timers: based on real time (relative, "fire |
213 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
227 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
214 | o'clock"). |
228 | o'clock"). |
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290 | the difference between "AnyEvent->time" and "AnyEvent->now" into |
304 | the difference between "AnyEvent->time" and "AnyEvent->now" into |
291 | account. |
305 | account. |
292 | |
306 | |
293 | SIGNAL WATCHERS |
307 | SIGNAL WATCHERS |
294 | You can watch for signals using a signal watcher, "signal" is the signal |
308 | You can watch for signals using a signal watcher, "signal" is the signal |
295 | *name* without any "SIG" prefix, "cb" is the Perl callback to be invoked |
309 | *name* in uppercase and without any "SIG" prefix, "cb" is the Perl |
296 | whenever a signal occurs. |
310 | callback to be invoked whenever a signal occurs. |
297 | |
311 | |
298 | Although the callback might get passed parameters, their value and |
312 | Although the callback might get passed parameters, their value and |
299 | presence is undefined and you cannot rely on them. Portable AnyEvent |
313 | presence is undefined and you cannot rely on them. Portable AnyEvent |
300 | callbacks cannot use arguments passed to signal watcher callbacks. |
314 | callbacks cannot use arguments passed to signal watcher callbacks. |
301 | |
315 | |
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316 | |
330 | |
317 | CHILD PROCESS WATCHERS |
331 | CHILD PROCESS WATCHERS |
318 | You can also watch on a child process exit and catch its exit status. |
332 | You can also watch on a child process exit and catch its exit status. |
319 | |
333 | |
320 | The child process is specified by the "pid" argument (if set to 0, it |
334 | The child process is specified by the "pid" argument (if set to 0, it |
321 | watches for any child process exit). The watcher will trigger as often |
335 | watches for any child process exit). The watcher will triggered only |
322 | as status change for the child are received. This works by installing a |
336 | when the child process has finished and an exit status is available, not |
323 | signal handler for "SIGCHLD". The callback will be called with the pid |
337 | on any trace events (stopped/continued). |
324 | and exit status (as returned by waitpid), so unlike other watcher types, |
338 | |
325 | you *can* rely on child watcher callback arguments. |
339 | The callback will be called with the pid and exit status (as returned by |
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340 | waitpid), so unlike other watcher types, you *can* rely on child watcher |
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341 | callback arguments. |
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342 | |
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343 | This watcher type works by installing a signal handler for "SIGCHLD", |
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344 | and since it cannot be shared, nothing else should use SIGCHLD or reap |
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345 | random child processes (waiting for specific child processes, e.g. |
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346 | inside "system", is just fine). |
326 | |
347 | |
327 | There is a slight catch to child watchers, however: you usually start |
348 | There is a slight catch to child watchers, however: you usually start |
328 | them *after* the child process was created, and this means the process |
349 | them *after* the child process was created, and this means the process |
329 | could have exited already (and no SIGCHLD will be sent anymore). |
350 | could have exited already (and no SIGCHLD will be sent anymore). |
330 | |
351 | |
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337 | an AnyEvent program, you *have* to create at least one watcher before |
358 | an AnyEvent program, you *have* to create at least one watcher before |
338 | you "fork" the child (alternatively, you can call "AnyEvent::detect"). |
359 | you "fork" the child (alternatively, you can call "AnyEvent::detect"). |
339 | |
360 | |
340 | Example: fork a process and wait for it |
361 | Example: fork a process and wait for it |
341 | |
362 | |
342 | my $done = AnyEvent->condvar; |
363 | my $done = AnyEvent->condvar; |
343 | |
364 | |
344 | my $pid = fork or exit 5; |
365 | my $pid = fork or exit 5; |
345 | |
366 | |
346 | my $w = AnyEvent->child ( |
367 | my $w = AnyEvent->child ( |
347 | pid => $pid, |
368 | pid => $pid, |
348 | cb => sub { |
369 | cb => sub { |
349 | my ($pid, $status) = @_; |
370 | my ($pid, $status) = @_; |
350 | warn "pid $pid exited with status $status"; |
371 | warn "pid $pid exited with status $status"; |
351 | $done->send; |
372 | $done->send; |
352 | }, |
373 | }, |
353 | ); |
374 | ); |
354 | |
375 | |
355 | # do something else, then wait for process exit |
376 | # do something else, then wait for process exit |
356 | $done->recv; |
377 | $done->recv; |
357 | |
378 | |
358 | CONDITION VARIABLES |
379 | CONDITION VARIABLES |
359 | If you are familiar with some event loops you will know that all of them |
380 | If you are familiar with some event loops you will know that all of them |
360 | require you to run some blocking "loop", "run" or similar function that |
381 | require you to run some blocking "loop", "run" or similar function that |
361 | will actively watch for new events and call your callbacks. |
382 | will actively watch for new events and call your callbacks. |
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366 | The instrument to do that is called a "condition variable", so called |
387 | The instrument to do that is called a "condition variable", so called |
367 | because they represent a condition that must become true. |
388 | because they represent a condition that must become true. |
368 | |
389 | |
369 | Condition variables can be created by calling the "AnyEvent->condvar" |
390 | Condition variables can be created by calling the "AnyEvent->condvar" |
370 | method, usually without arguments. The only argument pair allowed is |
391 | method, usually without arguments. The only argument pair allowed is |
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392 | |
371 | "cb", which specifies a callback to be called when the condition |
393 | "cb", which specifies a callback to be called when the condition |
372 | variable becomes true. |
394 | variable becomes true, with the condition variable as the first argument |
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395 | (but not the results). |
373 | |
396 | |
374 | After creation, the condition variable is "false" until it becomes |
397 | After creation, the condition variable is "false" until it becomes |
375 | "true" by calling the "send" method (or calling the condition variable |
398 | "true" by calling the "send" method (or calling the condition variable |
376 | as if it were a callback, read about the caveats in the description for |
399 | as if it were a callback, read about the caveats in the description for |
377 | the "->send" method). |
400 | the "->send" method). |
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433 | |
456 | |
434 | my $done = AnyEvent->condvar; |
457 | my $done = AnyEvent->condvar; |
435 | my $delay = AnyEvent->timer (after => 5, cb => $done); |
458 | my $delay = AnyEvent->timer (after => 5, cb => $done); |
436 | $done->recv; |
459 | $done->recv; |
437 | |
460 | |
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461 | Example: Imagine an API that returns a condvar and doesn't support |
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462 | callbacks. This is how you make a synchronous call, for example from the |
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463 | main program: |
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464 | |
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465 | use AnyEvent::CouchDB; |
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466 | |
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467 | ... |
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468 | |
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469 | my @info = $couchdb->info->recv; |
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470 | |
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471 | And this is how you would just ste a callback to be called whenever the |
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472 | results are available: |
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473 | |
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474 | $couchdb->info->cb (sub { |
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475 | my @info = $_[0]->recv; |
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476 | }); |
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477 | |
438 | METHODS FOR PRODUCERS |
478 | METHODS FOR PRODUCERS |
439 | These methods should only be used by the producing side, i.e. the |
479 | These methods should only be used by the producing side, i.e. the |
440 | code/module that eventually sends the signal. Note that it is also the |
480 | code/module that eventually sends the signal. Note that it is also the |
441 | producer side which creates the condvar in most cases, but it isn't |
481 | producer side which creates the condvar in most cases, but it isn't |
442 | uncommon for the consumer to create it as well. |
482 | uncommon for the consumer to create it as well. |
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562 | |
602 | |
563 | $bool = $cv->ready |
603 | $bool = $cv->ready |
564 | Returns true when the condition is "true", i.e. whether "send" or |
604 | Returns true when the condition is "true", i.e. whether "send" or |
565 | "croak" have been called. |
605 | "croak" have been called. |
566 | |
606 | |
567 | $cb = $cv->cb ([new callback]) |
607 | $cb = $cv->cb ($cb->($cv)) |
568 | This is a mutator function that returns the callback set and |
608 | This is a mutator function that returns the callback set and |
569 | optionally replaces it before doing so. |
609 | optionally replaces it before doing so. |
570 | |
610 | |
571 | The callback will be called when the condition becomes "true", i.e. |
611 | The callback will be called when the condition becomes "true", i.e. |
572 | when "send" or "croak" are called. Calling "recv" inside the |
612 | when "send" or "croak" are called, with the only argument being the |
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613 | condition variable itself. Calling "recv" inside the callback or at |
573 | callback or at any later time is guaranteed not to block. |
614 | any later time is guaranteed not to block. |
574 | |
615 | |
575 | GLOBAL VARIABLES AND FUNCTIONS |
616 | GLOBAL VARIABLES AND FUNCTIONS |
576 | $AnyEvent::MODEL |
617 | $AnyEvent::MODEL |
577 | Contains "undef" until the first watcher is being created. Then it |
618 | Contains "undef" until the first watcher is being created. Then it |
578 | contains the event model that is being used, which is the name of |
619 | contains the event model that is being used, which is the name of |
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692 | AnyEvent::Util |
733 | AnyEvent::Util |
693 | Contains various utility functions that replace often-used but |
734 | Contains various utility functions that replace often-used but |
694 | blocking functions such as "inet_aton" by event-/callback-based |
735 | blocking functions such as "inet_aton" by event-/callback-based |
695 | versions. |
736 | versions. |
696 | |
737 | |
697 | AnyEvent::Handle |
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698 | Provide read and write buffers and manages watchers for reads and |
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699 | writes. |
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700 | |
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701 | AnyEvent::Socket |
738 | AnyEvent::Socket |
702 | Provides various utility functions for (internet protocol) sockets, |
739 | Provides various utility functions for (internet protocol) sockets, |
703 | addresses and name resolution. Also functions to create non-blocking |
740 | addresses and name resolution. Also functions to create non-blocking |
704 | tcp connections or tcp servers, with IPv6 and SRV record support and |
741 | tcp connections or tcp servers, with IPv6 and SRV record support and |
705 | more. |
742 | more. |
706 | |
743 | |
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744 | AnyEvent::Handle |
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745 | Provide read and write buffers, manages watchers for reads and |
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746 | writes, supports raw and formatted I/O, I/O queued and fully |
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747 | transparent and non-blocking SSL/TLS. |
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748 | |
707 | AnyEvent::DNS |
749 | AnyEvent::DNS |
708 | Provides rich asynchronous DNS resolver capabilities. |
750 | Provides rich asynchronous DNS resolver capabilities. |
709 | |
751 | |
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752 | AnyEvent::HTTP |
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753 | A simple-to-use HTTP library that is capable of making a lot of |
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754 | concurrent HTTP requests. |
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755 | |
710 | AnyEvent::HTTPD |
756 | AnyEvent::HTTPD |
711 | Provides a simple web application server framework. |
757 | Provides a simple web application server framework. |
712 | |
758 | |
713 | AnyEvent::FastPing |
759 | AnyEvent::FastPing |
714 | The fastest ping in the west. |
760 | The fastest ping in the west. |
715 | |
761 | |
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762 | AnyEvent::DBI |
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763 | Executes DBI requests asynchronously in a proxy process. |
|
|
764 | |
|
|
765 | AnyEvent::AIO |
|
|
766 | Truly asynchronous I/O, should be in the toolbox of every event |
|
|
767 | programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent |
|
|
768 | together. |
|
|
769 | |
|
|
770 | AnyEvent::BDB |
|
|
771 | Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently |
|
|
772 | fuses BDB and AnyEvent together. |
|
|
773 | |
|
|
774 | AnyEvent::GPSD |
|
|
775 | A non-blocking interface to gpsd, a daemon delivering GPS |
|
|
776 | information. |
|
|
777 | |
|
|
778 | AnyEvent::IGS |
|
|
779 | A non-blocking interface to the Internet Go Server protocol (used by |
|
|
780 | App::IGS). |
|
|
781 | |
|
|
782 | AnyEvent::IRC |
|
|
783 | AnyEvent based IRC client module family (replacing the older |
716 | Net::IRC3 |
784 | Net::IRC3). |
717 | AnyEvent based IRC client module family. |
|
|
718 | |
785 | |
719 | Net::XMPP2 |
786 | Net::XMPP2 |
720 | AnyEvent based XMPP (Jabber protocol) module family. |
787 | AnyEvent based XMPP (Jabber protocol) module family. |
721 | |
788 | |
722 | Net::FCP |
789 | Net::FCP |
… | |
… | |
727 | High level API for event-based execution flow control. |
794 | High level API for event-based execution flow control. |
728 | |
795 | |
729 | Coro |
796 | Coro |
730 | Has special support for AnyEvent via Coro::AnyEvent. |
797 | Has special support for AnyEvent via Coro::AnyEvent. |
731 | |
798 | |
732 | AnyEvent::AIO, IO::AIO |
|
|
733 | Truly asynchronous I/O, should be in the toolbox of every event |
|
|
734 | programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent |
|
|
735 | together. |
|
|
736 | |
|
|
737 | AnyEvent::BDB, BDB |
|
|
738 | Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently |
|
|
739 | fuses IO::AIO and AnyEvent together. |
|
|
740 | |
|
|
741 | IO::Lambda |
799 | IO::Lambda |
742 | The lambda approach to I/O - don't ask, look there. Can use |
800 | The lambda approach to I/O - don't ask, look there. Can use |
743 | AnyEvent. |
801 | AnyEvent. |
744 | |
802 | |
745 | SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
803 | ERROR AND EXCEPTION HANDLING |
746 | This is an advanced topic that you do not normally need to use AnyEvent |
804 | In general, AnyEvent does not do any error handling - it relies on the |
747 | in a module. This section is only of use to event loop authors who want |
805 | caller to do that if required. The AnyEvent::Strict module (see also the |
748 | to provide AnyEvent compatibility. |
806 | "PERL_ANYEVENT_STRICT" environment variable, below) provides strict |
|
|
807 | checking of all AnyEvent methods, however, which is highly useful during |
|
|
808 | development. |
749 | |
809 | |
750 | If you need to support another event library which isn't directly |
810 | As for exception handling (i.e. runtime errors and exceptions thrown |
751 | supported by AnyEvent, you can supply your own interface to it by |
811 | while executing a callback), this is not only highly event-loop |
752 | pushing, before the first watcher gets created, the package name of the |
812 | specific, but also not in any way wrapped by this module, as this is the |
753 | event module and the package name of the interface to use onto |
813 | job of the main program. |
754 | @AnyEvent::REGISTRY. You can do that before and even without loading |
|
|
755 | AnyEvent, so it is reasonably cheap. |
|
|
756 | |
814 | |
757 | Example: |
815 | The pure perl event loop simply re-throws the exception (usually within |
758 | |
816 | "condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()", |
759 | push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::]; |
817 | Glib uses "install_exception_handler" and so on. |
760 | |
|
|
761 | This tells AnyEvent to (literally) use the "urxvt::anyevent::" |
|
|
762 | package/class when it finds the "urxvt" package/module is already |
|
|
763 | loaded. |
|
|
764 | |
|
|
765 | When AnyEvent is loaded and asked to find a suitable event model, it |
|
|
766 | will first check for the presence of urxvt by trying to "use" the |
|
|
767 | "urxvt::anyevent" module. |
|
|
768 | |
|
|
769 | The class should provide implementations for all watcher types. See |
|
|
770 | AnyEvent::Impl::EV (source code), AnyEvent::Impl::Glib (Source code) and |
|
|
771 | so on for actual examples. Use "perldoc -m AnyEvent::Impl::Glib" to see |
|
|
772 | the sources. |
|
|
773 | |
|
|
774 | If you don't provide "signal" and "child" watchers than AnyEvent will |
|
|
775 | provide suitable (hopefully) replacements. |
|
|
776 | |
|
|
777 | The above example isn't fictitious, the *rxvt-unicode* (a.k.a. urxvt) |
|
|
778 | terminal emulator uses the above line as-is. An interface isn't included |
|
|
779 | in AnyEvent because it doesn't make sense outside the embedded |
|
|
780 | interpreter inside *rxvt-unicode*, and it is updated and maintained as |
|
|
781 | part of the *rxvt-unicode* distribution. |
|
|
782 | |
|
|
783 | *rxvt-unicode* also cheats a bit by not providing blocking access to |
|
|
784 | condition variables: code blocking while waiting for a condition will |
|
|
785 | "die". This still works with most modules/usages, and blocking calls |
|
|
786 | must not be done in an interactive application, so it makes sense. |
|
|
787 | |
818 | |
788 | ENVIRONMENT VARIABLES |
819 | ENVIRONMENT VARIABLES |
789 | The following environment variables are used by this module: |
820 | The following environment variables are used by this module or its |
|
|
821 | submodules: |
790 | |
822 | |
791 | "PERL_ANYEVENT_VERBOSE" |
823 | "PERL_ANYEVENT_VERBOSE" |
792 | By default, AnyEvent will be completely silent except in fatal |
824 | By default, AnyEvent will be completely silent except in fatal |
793 | conditions. You can set this environment variable to make AnyEvent |
825 | conditions. You can set this environment variable to make AnyEvent |
794 | more talkative. |
826 | more talkative. |
… | |
… | |
797 | conditions, such as not being able to load the event model specified |
829 | conditions, such as not being able to load the event model specified |
798 | by "PERL_ANYEVENT_MODEL". |
830 | by "PERL_ANYEVENT_MODEL". |
799 | |
831 | |
800 | When set to 2 or higher, cause AnyEvent to report to STDERR which |
832 | When set to 2 or higher, cause AnyEvent to report to STDERR which |
801 | event model it chooses. |
833 | event model it chooses. |
|
|
834 | |
|
|
835 | "PERL_ANYEVENT_STRICT" |
|
|
836 | AnyEvent does not do much argument checking by default, as thorough |
|
|
837 | argument checking is very costly. Setting this variable to a true |
|
|
838 | value will cause AnyEvent to load "AnyEvent::Strict" and then to |
|
|
839 | thoroughly check the arguments passed to most method calls. If it |
|
|
840 | finds any problems it will croak. |
|
|
841 | |
|
|
842 | In other words, enables "strict" mode. |
|
|
843 | |
|
|
844 | Unlike "use strict", it is definitely recommended ot keep it off in |
|
|
845 | production. Keeping "PERL_ANYEVENT_STRICT=1" in your environment |
|
|
846 | while developing programs can be very useful, however. |
802 | |
847 | |
803 | "PERL_ANYEVENT_MODEL" |
848 | "PERL_ANYEVENT_MODEL" |
804 | This can be used to specify the event model to be used by AnyEvent, |
849 | This can be used to specify the event model to be used by AnyEvent, |
805 | before auto detection and -probing kicks in. It must be a string |
850 | before auto detection and -probing kicks in. It must be a string |
806 | consisting entirely of ASCII letters. The string "AnyEvent::Impl::" |
851 | consisting entirely of ASCII letters. The string "AnyEvent::Impl::" |
… | |
… | |
811 | This functionality might change in future versions. |
856 | This functionality might change in future versions. |
812 | |
857 | |
813 | For example, to force the pure perl model (AnyEvent::Impl::Perl) you |
858 | For example, to force the pure perl model (AnyEvent::Impl::Perl) you |
814 | could start your program like this: |
859 | could start your program like this: |
815 | |
860 | |
816 | PERL_ANYEVENT_MODEL=Perl perl ... |
861 | PERL_ANYEVENT_MODEL=Perl perl ... |
817 | |
862 | |
818 | "PERL_ANYEVENT_PROTOCOLS" |
863 | "PERL_ANYEVENT_PROTOCOLS" |
819 | Used by both AnyEvent::DNS and AnyEvent::Socket to determine |
864 | Used by both AnyEvent::DNS and AnyEvent::Socket to determine |
820 | preferences for IPv4 or IPv6. The default is unspecified (and might |
865 | preferences for IPv4 or IPv6. The default is unspecified (and might |
821 | change, or be the result of auto probing). |
866 | change, or be the result of auto probing). |
… | |
… | |
847 | EDNS0 in its DNS requests. |
892 | EDNS0 in its DNS requests. |
848 | |
893 | |
849 | "PERL_ANYEVENT_MAX_FORKS" |
894 | "PERL_ANYEVENT_MAX_FORKS" |
850 | The maximum number of child processes that |
895 | The maximum number of child processes that |
851 | "AnyEvent::Util::fork_call" will create in parallel. |
896 | "AnyEvent::Util::fork_call" will create in parallel. |
|
|
897 | |
|
|
898 | SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
|
|
899 | This is an advanced topic that you do not normally need to use AnyEvent |
|
|
900 | in a module. This section is only of use to event loop authors who want |
|
|
901 | to provide AnyEvent compatibility. |
|
|
902 | |
|
|
903 | If you need to support another event library which isn't directly |
|
|
904 | supported by AnyEvent, you can supply your own interface to it by |
|
|
905 | pushing, before the first watcher gets created, the package name of the |
|
|
906 | event module and the package name of the interface to use onto |
|
|
907 | @AnyEvent::REGISTRY. You can do that before and even without loading |
|
|
908 | AnyEvent, so it is reasonably cheap. |
|
|
909 | |
|
|
910 | Example: |
|
|
911 | |
|
|
912 | push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::]; |
|
|
913 | |
|
|
914 | This tells AnyEvent to (literally) use the "urxvt::anyevent::" |
|
|
915 | package/class when it finds the "urxvt" package/module is already |
|
|
916 | loaded. |
|
|
917 | |
|
|
918 | When AnyEvent is loaded and asked to find a suitable event model, it |
|
|
919 | will first check for the presence of urxvt by trying to "use" the |
|
|
920 | "urxvt::anyevent" module. |
|
|
921 | |
|
|
922 | The class should provide implementations for all watcher types. See |
|
|
923 | AnyEvent::Impl::EV (source code), AnyEvent::Impl::Glib (Source code) and |
|
|
924 | so on for actual examples. Use "perldoc -m AnyEvent::Impl::Glib" to see |
|
|
925 | the sources. |
|
|
926 | |
|
|
927 | If you don't provide "signal" and "child" watchers than AnyEvent will |
|
|
928 | provide suitable (hopefully) replacements. |
|
|
929 | |
|
|
930 | The above example isn't fictitious, the *rxvt-unicode* (a.k.a. urxvt) |
|
|
931 | terminal emulator uses the above line as-is. An interface isn't included |
|
|
932 | in AnyEvent because it doesn't make sense outside the embedded |
|
|
933 | interpreter inside *rxvt-unicode*, and it is updated and maintained as |
|
|
934 | part of the *rxvt-unicode* distribution. |
|
|
935 | |
|
|
936 | *rxvt-unicode* also cheats a bit by not providing blocking access to |
|
|
937 | condition variables: code blocking while waiting for a condition will |
|
|
938 | "die". This still works with most modules/usages, and blocking calls |
|
|
939 | must not be done in an interactive application, so it makes sense. |
852 | |
940 | |
853 | EXAMPLE PROGRAM |
941 | EXAMPLE PROGRAM |
854 | The following program uses an I/O watcher to read data from STDIN, a |
942 | The following program uses an I/O watcher to read data from STDIN, a |
855 | timer to display a message once per second, and a condition variable to |
943 | timer to display a message once per second, and a condition variable to |
856 | quit the program when the user enters quit: |
944 | quit the program when the user enters quit: |
… | |
… | |
1243 | |
1331 | |
1244 | Summary |
1332 | Summary |
1245 | * C-based event loops perform very well with small number of watchers, |
1333 | * C-based event loops perform very well with small number of watchers, |
1246 | as the management overhead dominates. |
1334 | as the management overhead dominates. |
1247 | |
1335 | |
|
|
1336 | SIGNALS |
|
|
1337 | AnyEvent currently installs handlers for these signals: |
|
|
1338 | |
|
|
1339 | SIGCHLD |
|
|
1340 | A handler for "SIGCHLD" is installed by AnyEvent's child watcher |
|
|
1341 | emulation for event loops that do not support them natively. Also, |
|
|
1342 | some event loops install a similar handler. |
|
|
1343 | |
|
|
1344 | SIGPIPE |
|
|
1345 | A no-op handler is installed for "SIGPIPE" when $SIG{PIPE} is |
|
|
1346 | "undef" when AnyEvent gets loaded. |
|
|
1347 | |
|
|
1348 | The rationale for this is that AnyEvent users usually do not really |
|
|
1349 | depend on SIGPIPE delivery (which is purely an optimisation for |
|
|
1350 | shell use, or badly-written programs), but "SIGPIPE" can cause |
|
|
1351 | spurious and rare program exits as a lot of people do not expect |
|
|
1352 | "SIGPIPE" when writing to some random socket. |
|
|
1353 | |
|
|
1354 | The rationale for installing a no-op handler as opposed to ignoring |
|
|
1355 | it is that this way, the handler will be restored to defaults on |
|
|
1356 | exec. |
|
|
1357 | |
|
|
1358 | Feel free to install your own handler, or reset it to defaults. |
|
|
1359 | |
1248 | FORK |
1360 | FORK |
1249 | Most event libraries are not fork-safe. The ones who are usually are |
1361 | Most event libraries are not fork-safe. The ones who are usually are |
1250 | because they rely on inefficient but fork-safe "select" or "poll" calls. |
1362 | because they rely on inefficient but fork-safe "select" or "poll" calls. |
1251 | Only EV is fully fork-aware. |
1363 | Only EV is fully fork-aware. |
1252 | |
1364 | |
… | |
… | |
1262 | model than specified in the variable. |
1374 | model than specified in the variable. |
1263 | |
1375 | |
1264 | You can make AnyEvent completely ignore this variable by deleting it |
1376 | You can make AnyEvent completely ignore this variable by deleting it |
1265 | before the first watcher gets created, e.g. with a "BEGIN" block: |
1377 | before the first watcher gets created, e.g. with a "BEGIN" block: |
1266 | |
1378 | |
1267 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
1379 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
1268 | |
1380 | |
1269 | use AnyEvent; |
1381 | use AnyEvent; |
1270 | |
1382 | |
1271 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
1383 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
1272 | be used to probe what backend is used and gain other information (which |
1384 | be used to probe what backend is used and gain other information (which |
1273 | is probably even less useful to an attacker than PERL_ANYEVENT_MODEL). |
1385 | is probably even less useful to an attacker than PERL_ANYEVENT_MODEL), |
|
|
1386 | and $ENV{PERL_ANYEGENT_STRICT}. |
|
|
1387 | |
|
|
1388 | BUGS |
|
|
1389 | Perl 5.8 has numerous memleaks that sometimes hit this module and are |
|
|
1390 | hard to work around. If you suffer from memleaks, first upgrade to Perl |
|
|
1391 | 5.10 and check wether the leaks still show up. (Perl 5.10.0 has other |
|
|
1392 | annoying mamleaks, such as leaking on "map" and "grep" but it is usually |
|
|
1393 | not as pronounced). |
1274 | |
1394 | |
1275 | SEE ALSO |
1395 | SEE ALSO |
1276 | Utility functions: AnyEvent::Util. |
1396 | Utility functions: AnyEvent::Util. |
1277 | |
1397 | |
1278 | Event modules: EV, EV::Glib, Glib::EV, Event, Glib::Event, Glib, Tk, |
1398 | Event modules: EV, EV::Glib, Glib::EV, Event, Glib::Event, Glib, Tk, |
… | |
… | |
1290 | Coroutine support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event, |
1410 | Coroutine support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event, |
1291 | |
1411 | |
1292 | Nontrivial usage examples: Net::FCP, Net::XMPP2, AnyEvent::DNS. |
1412 | Nontrivial usage examples: Net::FCP, Net::XMPP2, AnyEvent::DNS. |
1293 | |
1413 | |
1294 | AUTHOR |
1414 | AUTHOR |
1295 | Marc Lehmann <schmorp@schmorp.de> |
1415 | Marc Lehmann <schmorp@schmorp.de> |
1296 | http://home.schmorp.de/ |
1416 | http://home.schmorp.de/ |
1297 | |
1417 | |