1 | =head1 NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | AnyEvent - provide framework for multiple event loops |
3 | AnyEvent - provide framework for multiple event loops |
4 | |
4 | |
5 | EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops |
5 | EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops |
6 | |
6 | |
7 | =head1 SYNOPSIS |
7 | =head1 SYNOPSIS |
8 | |
8 | |
9 | use AnyEvent; |
9 | use AnyEvent; |
10 | |
10 | |
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15 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
15 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
16 | ... |
16 | ... |
17 | }); |
17 | }); |
18 | |
18 | |
19 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
19 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
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20 | $w->send; # wake up current and all future recv's |
20 | $w->wait; # enters "main loop" till $condvar gets ->broadcast |
21 | $w->recv; # enters "main loop" till $condvar gets ->send |
21 | $w->broadcast; # wake up current and all future wait's |
22 | |
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23 | =head1 INTRODUCTION/TUTORIAL |
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24 | |
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25 | This manpage is mainly a reference manual. If you are interested |
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26 | in a tutorial or some gentle introduction, have a look at the |
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27 | L<AnyEvent::Intro> manpage. |
22 | |
28 | |
23 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
29 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
24 | |
30 | |
25 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
31 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
26 | nowadays. So what is different about AnyEvent? |
32 | nowadays. So what is different about AnyEvent? |
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48 | isn't itself. What's worse, all the potential users of your module are |
54 | isn't itself. What's worse, all the potential users of your module are |
49 | I<also> forced to use the same event loop you use. |
55 | I<also> forced to use the same event loop you use. |
50 | |
56 | |
51 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
57 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
52 | fine. AnyEvent + Tk works fine etc. etc. but none of these work together |
58 | fine. AnyEvent + Tk works fine etc. etc. but none of these work together |
53 | with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if |
59 | with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if |
54 | your module uses one of those, every user of your module has to use it, |
60 | your module uses one of those, every user of your module has to use it, |
55 | too. But if your module uses AnyEvent, it works transparently with all |
61 | too. But if your module uses AnyEvent, it works transparently with all |
56 | event models it supports (including stuff like POE and IO::Async, as long |
62 | event models it supports (including stuff like POE and IO::Async, as long |
57 | as those use one of the supported event loops. It is trivial to add new |
63 | as those use one of the supported event loops. It is trivial to add new |
58 | event loops to AnyEvent, too, so it is future-proof). |
64 | event loops to AnyEvent, too, so it is future-proof). |
59 | |
65 | |
60 | In addition to being free of having to use I<the one and only true event |
66 | In addition to being free of having to use I<the one and only true event |
61 | model>, AnyEvent also is free of bloat and policy: with POE or similar |
67 | model>, AnyEvent also is free of bloat and policy: with POE or similar |
62 | modules, you get an enourmous amount of code and strict rules you have to |
68 | modules, you get an enormous amount of code and strict rules you have to |
63 | follow. AnyEvent, on the other hand, is lean and up to the point, by only |
69 | follow. AnyEvent, on the other hand, is lean and up to the point, by only |
64 | offering the functionality that is necessary, in as thin as a wrapper as |
70 | offering the functionality that is necessary, in as thin as a wrapper as |
65 | technically possible. |
71 | technically possible. |
66 | |
72 | |
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73 | Of course, AnyEvent comes with a big (and fully optional!) toolbox |
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74 | of useful functionality, such as an asynchronous DNS resolver, 100% |
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75 | non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms |
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76 | such as Windows) and lots of real-world knowledge and workarounds for |
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77 | platform bugs and differences. |
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78 | |
67 | Of course, if you want lots of policy (this can arguably be somewhat |
79 | Now, if you I<do want> lots of policy (this can arguably be somewhat |
68 | useful) and you want to force your users to use the one and only event |
80 | useful) and you want to force your users to use the one and only event |
69 | model, you should I<not> use this module. |
81 | model, you should I<not> use this module. |
70 | |
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71 | #TODO# |
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72 | |
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73 | Net::IRC3 |
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74 | AnyEvent::HTTPD |
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75 | AnyEvent::DNS |
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76 | IO::AnyEvent |
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77 | Net::FPing |
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78 | Net::XMPP2 |
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79 | Coro |
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80 | |
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81 | AnyEvent::IRC |
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82 | AnyEvent::HTTPD |
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83 | AnyEvent::DNS |
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84 | AnyEvent::Handle |
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85 | AnyEvent::Socket |
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86 | AnyEvent::FPing |
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87 | AnyEvent::XMPP |
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88 | AnyEvent::SNMP |
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89 | Coro |
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90 | |
82 | |
91 | =head1 DESCRIPTION |
83 | =head1 DESCRIPTION |
92 | |
84 | |
93 | L<AnyEvent> provides an identical interface to multiple event loops. This |
85 | L<AnyEvent> provides an identical interface to multiple event loops. This |
94 | allows module authors to utilise an event loop without forcing module |
86 | allows module authors to utilise an event loop without forcing module |
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98 | The interface itself is vaguely similar, but not identical to the L<Event> |
90 | The interface itself is vaguely similar, but not identical to the L<Event> |
99 | module. |
91 | module. |
100 | |
92 | |
101 | During the first call of any watcher-creation method, the module tries |
93 | During the first call of any watcher-creation method, the module tries |
102 | to detect the currently loaded event loop by probing whether one of the |
94 | to detect the currently loaded event loop by probing whether one of the |
103 | following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>, |
95 | following modules is already loaded: L<EV>, |
104 | L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, |
96 | L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, |
105 | L<POE>. The first one found is used. If none are found, the module tries |
97 | L<POE>. The first one found is used. If none are found, the module tries |
106 | to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl |
98 | to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl |
107 | adaptor should always succeed) in the order given. The first one that can |
99 | adaptor should always succeed) in the order given. The first one that can |
108 | be successfully loaded will be used. If, after this, still none could be |
100 | be successfully loaded will be used. If, after this, still none could be |
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122 | starts using it, all bets are off. Maybe you should tell their authors to |
114 | starts using it, all bets are off. Maybe you should tell their authors to |
123 | use AnyEvent so their modules work together with others seamlessly... |
115 | use AnyEvent so their modules work together with others seamlessly... |
124 | |
116 | |
125 | The pure-perl implementation of AnyEvent is called |
117 | The pure-perl implementation of AnyEvent is called |
126 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
118 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
127 | explicitly. |
119 | explicitly and enjoy the high availability of that event loop :) |
128 | |
120 | |
129 | =head1 WATCHERS |
121 | =head1 WATCHERS |
130 | |
122 | |
131 | AnyEvent has the central concept of a I<watcher>, which is an object that |
123 | AnyEvent has the central concept of a I<watcher>, which is an object that |
132 | stores relevant data for each kind of event you are waiting for, such as |
124 | stores relevant data for each kind of event you are waiting for, such as |
133 | the callback to call, the filehandle to watch, etc. |
125 | the callback to call, the file handle to watch, etc. |
134 | |
126 | |
135 | These watchers are normal Perl objects with normal Perl lifetime. After |
127 | These watchers are normal Perl objects with normal Perl lifetime. After |
136 | creating a watcher it will immediately "watch" for events and invoke the |
128 | creating a watcher it will immediately "watch" for events and invoke the |
137 | callback when the event occurs (of course, only when the event model |
129 | callback when the event occurs (of course, only when the event model |
138 | is in control). |
130 | is in control). |
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146 | Many watchers either are used with "recursion" (repeating timers for |
138 | Many watchers either are used with "recursion" (repeating timers for |
147 | example), or need to refer to their watcher object in other ways. |
139 | example), or need to refer to their watcher object in other ways. |
148 | |
140 | |
149 | An any way to achieve that is this pattern: |
141 | An any way to achieve that is this pattern: |
150 | |
142 | |
151 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
143 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
152 | # you can use $w here, for example to undef it |
144 | # you can use $w here, for example to undef it |
153 | undef $w; |
145 | undef $w; |
154 | }); |
146 | }); |
155 | |
147 | |
156 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
148 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
157 | my variables are only visible after the statement in which they are |
149 | my variables are only visible after the statement in which they are |
158 | declared. |
150 | declared. |
159 | |
151 | |
160 | =head2 I/O WATCHERS |
152 | =head2 I/O WATCHERS |
161 | |
153 | |
162 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
154 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
163 | with the following mandatory key-value pairs as arguments: |
155 | with the following mandatory key-value pairs as arguments: |
164 | |
156 | |
165 | C<fh> the Perl I<file handle> (I<not> file descriptor) to watch |
157 | C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events |
166 | for events. C<poll> must be a string that is either C<r> or C<w>, |
158 | (AnyEvent might or might not keep a reference to this file handle). C<poll> |
167 | which creates a watcher waiting for "r"eadable or "w"ritable events, |
159 | must be a string that is either C<r> or C<w>, which creates a watcher |
168 | respectively. C<cb> is the callback to invoke each time the file handle |
160 | waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the |
169 | becomes ready. |
161 | callback to invoke each time the file handle becomes ready. |
170 | |
162 | |
171 | Although the callback might get passed parameters, their value and |
163 | Although the callback might get passed parameters, their value and |
172 | presence is undefined and you cannot rely on them. Portable AnyEvent |
164 | presence is undefined and you cannot rely on them. Portable AnyEvent |
173 | callbacks cannot use arguments passed to I/O watcher callbacks. |
165 | callbacks cannot use arguments passed to I/O watcher callbacks. |
174 | |
166 | |
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178 | |
170 | |
179 | Some event loops issue spurious readyness notifications, so you should |
171 | Some event loops issue spurious readyness notifications, so you should |
180 | always use non-blocking calls when reading/writing from/to your file |
172 | always use non-blocking calls when reading/writing from/to your file |
181 | handles. |
173 | handles. |
182 | |
174 | |
183 | Example: |
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184 | |
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185 | # wait for readability of STDIN, then read a line and disable the watcher |
175 | Example: wait for readability of STDIN, then read a line and disable the |
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176 | watcher. |
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177 | |
186 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
178 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
187 | chomp (my $input = <STDIN>); |
179 | chomp (my $input = <STDIN>); |
188 | warn "read: $input\n"; |
180 | warn "read: $input\n"; |
189 | undef $w; |
181 | undef $w; |
190 | }); |
182 | }); |
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200 | |
192 | |
201 | Although the callback might get passed parameters, their value and |
193 | Although the callback might get passed parameters, their value and |
202 | presence is undefined and you cannot rely on them. Portable AnyEvent |
194 | presence is undefined and you cannot rely on them. Portable AnyEvent |
203 | callbacks cannot use arguments passed to time watcher callbacks. |
195 | callbacks cannot use arguments passed to time watcher callbacks. |
204 | |
196 | |
205 | The timer callback will be invoked at most once: if you want a repeating |
197 | The callback will normally be invoked once only. If you specify another |
206 | timer you have to create a new watcher (this is a limitation by both Tk |
198 | parameter, C<interval>, as a strictly positive number (> 0), then the |
207 | and Glib). |
199 | callback will be invoked regularly at that interval (in fractional |
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200 | seconds) after the first invocation. If C<interval> is specified with a |
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201 | false value, then it is treated as if it were missing. |
208 | |
202 | |
209 | Example: |
203 | The callback will be rescheduled before invoking the callback, but no |
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204 | attempt is done to avoid timer drift in most backends, so the interval is |
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205 | only approximate. |
210 | |
206 | |
211 | # fire an event after 7.7 seconds |
207 | Example: fire an event after 7.7 seconds. |
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208 | |
212 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
209 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
213 | warn "timeout\n"; |
210 | warn "timeout\n"; |
214 | }); |
211 | }); |
215 | |
212 | |
216 | # to cancel the timer: |
213 | # to cancel the timer: |
217 | undef $w; |
214 | undef $w; |
218 | |
215 | |
219 | Example 2: |
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220 | |
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221 | # fire an event after 0.5 seconds, then roughly every second |
216 | Example 2: fire an event after 0.5 seconds, then roughly every second. |
222 | my $w; |
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223 | |
217 | |
224 | my $cb = sub { |
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225 | # cancel the old timer while creating a new one |
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226 | $w = AnyEvent->timer (after => 1, cb => $cb); |
218 | my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub { |
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219 | warn "timeout\n"; |
227 | }; |
220 | }; |
228 | |
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229 | # start the "loop" by creating the first watcher |
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230 | $w = AnyEvent->timer (after => 0.5, cb => $cb); |
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231 | |
221 | |
232 | =head3 TIMING ISSUES |
222 | =head3 TIMING ISSUES |
233 | |
223 | |
234 | There are two ways to handle timers: based on real time (relative, "fire |
224 | There are two ways to handle timers: based on real time (relative, "fire |
235 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
225 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
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247 | timers. |
237 | timers. |
248 | |
238 | |
249 | AnyEvent always prefers relative timers, if available, matching the |
239 | AnyEvent always prefers relative timers, if available, matching the |
250 | AnyEvent API. |
240 | AnyEvent API. |
251 | |
241 | |
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242 | AnyEvent has two additional methods that return the "current time": |
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243 | |
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244 | =over 4 |
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245 | |
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246 | =item AnyEvent->time |
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247 | |
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248 | This returns the "current wallclock time" as a fractional number of |
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249 | seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time> |
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250 | return, and the result is guaranteed to be compatible with those). |
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251 | |
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252 | It progresses independently of any event loop processing, i.e. each call |
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253 | will check the system clock, which usually gets updated frequently. |
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254 | |
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255 | =item AnyEvent->now |
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256 | |
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257 | This also returns the "current wallclock time", but unlike C<time>, above, |
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258 | this value might change only once per event loop iteration, depending on |
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259 | the event loop (most return the same time as C<time>, above). This is the |
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260 | time that AnyEvent's timers get scheduled against. |
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261 | |
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262 | I<In almost all cases (in all cases if you don't care), this is the |
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263 | function to call when you want to know the current time.> |
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264 | |
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265 | This function is also often faster then C<< AnyEvent->time >>, and |
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266 | thus the preferred method if you want some timestamp (for example, |
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267 | L<AnyEvent::Handle> uses this to update it's activity timeouts). |
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268 | |
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269 | The rest of this section is only of relevance if you try to be very exact |
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270 | with your timing, you can skip it without bad conscience. |
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271 | |
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272 | For a practical example of when these times differ, consider L<Event::Lib> |
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273 | and L<EV> and the following set-up: |
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274 | |
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275 | The event loop is running and has just invoked one of your callback at |
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276 | time=500 (assume no other callbacks delay processing). In your callback, |
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277 | you wait a second by executing C<sleep 1> (blocking the process for a |
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278 | second) and then (at time=501) you create a relative timer that fires |
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279 | after three seconds. |
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280 | |
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281 | With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will |
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282 | both return C<501>, because that is the current time, and the timer will |
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283 | be scheduled to fire at time=504 (C<501> + C<3>). |
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284 | |
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285 | With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current |
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286 | time), but C<< AnyEvent->now >> returns C<500>, as that is the time the |
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287 | last event processing phase started. With L<EV>, your timer gets scheduled |
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288 | to run at time=503 (C<500> + C<3>). |
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289 | |
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290 | In one sense, L<Event::Lib> is more exact, as it uses the current time |
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291 | regardless of any delays introduced by event processing. However, most |
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292 | callbacks do not expect large delays in processing, so this causes a |
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293 | higher drift (and a lot more system calls to get the current time). |
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294 | |
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295 | In another sense, L<EV> is more exact, as your timer will be scheduled at |
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296 | the same time, regardless of how long event processing actually took. |
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297 | |
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298 | In either case, if you care (and in most cases, you don't), then you |
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299 | can get whatever behaviour you want with any event loop, by taking the |
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300 | difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into |
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301 | account. |
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302 | |
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303 | =back |
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304 | |
252 | =head2 SIGNAL WATCHERS |
305 | =head2 SIGNAL WATCHERS |
253 | |
306 | |
254 | You can watch for signals using a signal watcher, C<signal> is the signal |
307 | You can watch for signals using a signal watcher, C<signal> is the signal |
255 | I<name> without any C<SIG> prefix, C<cb> is the Perl callback to |
308 | I<name> without any C<SIG> prefix, C<cb> is the Perl callback to |
256 | be invoked whenever a signal occurs. |
309 | be invoked whenever a signal occurs. |
257 | |
310 | |
258 | Although the callback might get passed parameters, their value and |
311 | Although the callback might get passed parameters, their value and |
259 | presence is undefined and you cannot rely on them. Portable AnyEvent |
312 | presence is undefined and you cannot rely on them. Portable AnyEvent |
260 | callbacks cannot use arguments passed to signal watcher callbacks. |
313 | callbacks cannot use arguments passed to signal watcher callbacks. |
261 | |
314 | |
262 | Multiple signal occurances can be clumped together into one callback |
315 | Multiple signal occurrences can be clumped together into one callback |
263 | invocation, and callback invocation will be synchronous. synchronous means |
316 | invocation, and callback invocation will be synchronous. Synchronous means |
264 | that it might take a while until the signal gets handled by the process, |
317 | that it might take a while until the signal gets handled by the process, |
265 | but it is guarenteed not to interrupt any other callbacks. |
318 | but it is guaranteed not to interrupt any other callbacks. |
266 | |
319 | |
267 | The main advantage of using these watchers is that you can share a signal |
320 | The main advantage of using these watchers is that you can share a signal |
268 | between multiple watchers. |
321 | between multiple watchers. |
269 | |
322 | |
270 | This watcher might use C<%SIG>, so programs overwriting those signals |
323 | This watcher might use C<%SIG>, so programs overwriting those signals |
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297 | AnyEvent program, you I<have> to create at least one watcher before you |
350 | AnyEvent program, you I<have> to create at least one watcher before you |
298 | C<fork> the child (alternatively, you can call C<AnyEvent::detect>). |
351 | C<fork> the child (alternatively, you can call C<AnyEvent::detect>). |
299 | |
352 | |
300 | Example: fork a process and wait for it |
353 | Example: fork a process and wait for it |
301 | |
354 | |
302 | my $done = AnyEvent->condvar; |
355 | my $done = AnyEvent->condvar; |
303 | |
356 | |
304 | AnyEvent::detect; # force event module to be initialised |
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305 | |
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306 | my $pid = fork or exit 5; |
357 | my $pid = fork or exit 5; |
307 | |
358 | |
308 | my $w = AnyEvent->child ( |
359 | my $w = AnyEvent->child ( |
309 | pid => $pid, |
360 | pid => $pid, |
310 | cb => sub { |
361 | cb => sub { |
311 | my ($pid, $status) = @_; |
362 | my ($pid, $status) = @_; |
312 | warn "pid $pid exited with status $status"; |
363 | warn "pid $pid exited with status $status"; |
313 | $done->broadcast; |
364 | $done->send; |
314 | }, |
365 | }, |
315 | ); |
366 | ); |
316 | |
367 | |
317 | # do something else, then wait for process exit |
368 | # do something else, then wait for process exit |
318 | $done->wait; |
369 | $done->recv; |
319 | |
370 | |
320 | =head2 CONDITION VARIABLES |
371 | =head2 CONDITION VARIABLES |
321 | |
372 | |
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373 | If you are familiar with some event loops you will know that all of them |
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374 | require you to run some blocking "loop", "run" or similar function that |
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375 | will actively watch for new events and call your callbacks. |
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376 | |
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377 | AnyEvent is different, it expects somebody else to run the event loop and |
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378 | will only block when necessary (usually when told by the user). |
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379 | |
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380 | The instrument to do that is called a "condition variable", so called |
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381 | because they represent a condition that must become true. |
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382 | |
322 | Condition variables can be created by calling the C<< AnyEvent->condvar >> |
383 | Condition variables can be created by calling the C<< AnyEvent->condvar |
323 | method without any arguments. |
384 | >> method, usually without arguments. The only argument pair allowed is |
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385 | C<cb>, which specifies a callback to be called when the condition variable |
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386 | becomes true. |
324 | |
387 | |
325 | A condition variable waits for a condition - precisely that the C<< |
388 | After creation, the condition variable is "false" until it becomes "true" |
326 | ->broadcast >> method has been called. |
389 | by calling the C<send> method (or calling the condition variable as if it |
|
|
390 | were a callback, read about the caveats in the description for the C<< |
|
|
391 | ->send >> method). |
327 | |
392 | |
328 | They are very useful to signal that a condition has been fulfilled, for |
393 | Condition variables are similar to callbacks, except that you can |
|
|
394 | optionally wait for them. They can also be called merge points - points |
|
|
395 | in time where multiple outstanding events have been processed. And yet |
|
|
396 | another way to call them is transactions - each condition variable can be |
|
|
397 | used to represent a transaction, which finishes at some point and delivers |
|
|
398 | a result. |
|
|
399 | |
|
|
400 | Condition variables are very useful to signal that something has finished, |
329 | example, if you write a module that does asynchronous http requests, |
401 | for example, if you write a module that does asynchronous http requests, |
330 | then a condition variable would be the ideal candidate to signal the |
402 | then a condition variable would be the ideal candidate to signal the |
331 | availability of results. |
403 | availability of results. The user can either act when the callback is |
|
|
404 | called or can synchronously C<< ->recv >> for the results. |
332 | |
405 | |
333 | You can also use condition variables to block your main program until |
406 | You can also use them to simulate traditional event loops - for example, |
334 | an event occurs - for example, you could C<< ->wait >> in your main |
407 | you can block your main program until an event occurs - for example, you |
335 | program until the user clicks the Quit button in your app, which would C<< |
408 | could C<< ->recv >> in your main program until the user clicks the Quit |
336 | ->broadcast >> the "quit" event. |
409 | button of your app, which would C<< ->send >> the "quit" event. |
337 | |
410 | |
338 | Note that condition variables recurse into the event loop - if you have |
411 | Note that condition variables recurse into the event loop - if you have |
339 | two pirces of code that call C<< ->wait >> in a round-robbin fashion, you |
412 | two pieces of code that call C<< ->recv >> in a round-robin fashion, you |
340 | lose. Therefore, condition variables are good to export to your caller, but |
413 | lose. Therefore, condition variables are good to export to your caller, but |
341 | you should avoid making a blocking wait yourself, at least in callbacks, |
414 | you should avoid making a blocking wait yourself, at least in callbacks, |
342 | as this asks for trouble. |
415 | as this asks for trouble. |
343 | |
416 | |
344 | This object has two methods: |
417 | Condition variables are represented by hash refs in perl, and the keys |
|
|
418 | used by AnyEvent itself are all named C<_ae_XXX> to make subclassing |
|
|
419 | easy (it is often useful to build your own transaction class on top of |
|
|
420 | AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call |
|
|
421 | it's C<new> method in your own C<new> method. |
|
|
422 | |
|
|
423 | There are two "sides" to a condition variable - the "producer side" which |
|
|
424 | eventually calls C<< -> send >>, and the "consumer side", which waits |
|
|
425 | for the send to occur. |
|
|
426 | |
|
|
427 | Example: wait for a timer. |
|
|
428 | |
|
|
429 | # wait till the result is ready |
|
|
430 | my $result_ready = AnyEvent->condvar; |
|
|
431 | |
|
|
432 | # do something such as adding a timer |
|
|
433 | # or socket watcher the calls $result_ready->send |
|
|
434 | # when the "result" is ready. |
|
|
435 | # in this case, we simply use a timer: |
|
|
436 | my $w = AnyEvent->timer ( |
|
|
437 | after => 1, |
|
|
438 | cb => sub { $result_ready->send }, |
|
|
439 | ); |
|
|
440 | |
|
|
441 | # this "blocks" (while handling events) till the callback |
|
|
442 | # calls send |
|
|
443 | $result_ready->recv; |
|
|
444 | |
|
|
445 | Example: wait for a timer, but take advantage of the fact that |
|
|
446 | condition variables are also code references. |
|
|
447 | |
|
|
448 | my $done = AnyEvent->condvar; |
|
|
449 | my $delay = AnyEvent->timer (after => 5, cb => $done); |
|
|
450 | $done->recv; |
|
|
451 | |
|
|
452 | =head3 METHODS FOR PRODUCERS |
|
|
453 | |
|
|
454 | These methods should only be used by the producing side, i.e. the |
|
|
455 | code/module that eventually sends the signal. Note that it is also |
|
|
456 | the producer side which creates the condvar in most cases, but it isn't |
|
|
457 | uncommon for the consumer to create it as well. |
345 | |
458 | |
346 | =over 4 |
459 | =over 4 |
347 | |
460 | |
|
|
461 | =item $cv->send (...) |
|
|
462 | |
|
|
463 | Flag the condition as ready - a running C<< ->recv >> and all further |
|
|
464 | calls to C<recv> will (eventually) return after this method has been |
|
|
465 | called. If nobody is waiting the send will be remembered. |
|
|
466 | |
|
|
467 | If a callback has been set on the condition variable, it is called |
|
|
468 | immediately from within send. |
|
|
469 | |
|
|
470 | Any arguments passed to the C<send> call will be returned by all |
|
|
471 | future C<< ->recv >> calls. |
|
|
472 | |
|
|
473 | Condition variables are overloaded so one can call them directly |
|
|
474 | (as a code reference). Calling them directly is the same as calling |
|
|
475 | C<send>. Note, however, that many C-based event loops do not handle |
|
|
476 | overloading, so as tempting as it may be, passing a condition variable |
|
|
477 | instead of a callback does not work. Both the pure perl and EV loops |
|
|
478 | support overloading, however, as well as all functions that use perl to |
|
|
479 | invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for |
|
|
480 | example). |
|
|
481 | |
|
|
482 | =item $cv->croak ($error) |
|
|
483 | |
|
|
484 | Similar to send, but causes all call's to C<< ->recv >> to invoke |
|
|
485 | C<Carp::croak> with the given error message/object/scalar. |
|
|
486 | |
|
|
487 | This can be used to signal any errors to the condition variable |
|
|
488 | user/consumer. |
|
|
489 | |
|
|
490 | =item $cv->begin ([group callback]) |
|
|
491 | |
348 | =item $cv->wait |
492 | =item $cv->end |
349 | |
493 | |
350 | Wait (blocking if necessary) until the C<< ->broadcast >> method has been |
494 | These two methods are EXPERIMENTAL and MIGHT CHANGE. |
|
|
495 | |
|
|
496 | These two methods can be used to combine many transactions/events into |
|
|
497 | one. For example, a function that pings many hosts in parallel might want |
|
|
498 | to use a condition variable for the whole process. |
|
|
499 | |
|
|
500 | Every call to C<< ->begin >> will increment a counter, and every call to |
|
|
501 | C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end |
|
|
502 | >>, the (last) callback passed to C<begin> will be executed. That callback |
|
|
503 | is I<supposed> to call C<< ->send >>, but that is not required. If no |
|
|
504 | callback was set, C<send> will be called without any arguments. |
|
|
505 | |
|
|
506 | Let's clarify this with the ping example: |
|
|
507 | |
|
|
508 | my $cv = AnyEvent->condvar; |
|
|
509 | |
|
|
510 | my %result; |
|
|
511 | $cv->begin (sub { $cv->send (\%result) }); |
|
|
512 | |
|
|
513 | for my $host (@list_of_hosts) { |
|
|
514 | $cv->begin; |
|
|
515 | ping_host_then_call_callback $host, sub { |
|
|
516 | $result{$host} = ...; |
|
|
517 | $cv->end; |
|
|
518 | }; |
|
|
519 | } |
|
|
520 | |
|
|
521 | $cv->end; |
|
|
522 | |
|
|
523 | This code fragment supposedly pings a number of hosts and calls |
|
|
524 | C<send> after results for all then have have been gathered - in any |
|
|
525 | order. To achieve this, the code issues a call to C<begin> when it starts |
|
|
526 | each ping request and calls C<end> when it has received some result for |
|
|
527 | it. Since C<begin> and C<end> only maintain a counter, the order in which |
|
|
528 | results arrive is not relevant. |
|
|
529 | |
|
|
530 | There is an additional bracketing call to C<begin> and C<end> outside the |
|
|
531 | loop, which serves two important purposes: first, it sets the callback |
|
|
532 | to be called once the counter reaches C<0>, and second, it ensures that |
|
|
533 | C<send> is called even when C<no> hosts are being pinged (the loop |
|
|
534 | doesn't execute once). |
|
|
535 | |
|
|
536 | This is the general pattern when you "fan out" into multiple subrequests: |
|
|
537 | use an outer C<begin>/C<end> pair to set the callback and ensure C<end> |
|
|
538 | is called at least once, and then, for each subrequest you start, call |
|
|
539 | C<begin> and for each subrequest you finish, call C<end>. |
|
|
540 | |
|
|
541 | =back |
|
|
542 | |
|
|
543 | =head3 METHODS FOR CONSUMERS |
|
|
544 | |
|
|
545 | These methods should only be used by the consuming side, i.e. the |
|
|
546 | code awaits the condition. |
|
|
547 | |
|
|
548 | =over 4 |
|
|
549 | |
|
|
550 | =item $cv->recv |
|
|
551 | |
|
|
552 | Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak |
351 | called on c<$cv>, while servicing other watchers normally. |
553 | >> methods have been called on c<$cv>, while servicing other watchers |
|
|
554 | normally. |
352 | |
555 | |
353 | You can only wait once on a condition - additional calls will return |
556 | You can only wait once on a condition - additional calls are valid but |
354 | immediately. |
557 | will return immediately. |
|
|
558 | |
|
|
559 | If an error condition has been set by calling C<< ->croak >>, then this |
|
|
560 | function will call C<croak>. |
|
|
561 | |
|
|
562 | In list context, all parameters passed to C<send> will be returned, |
|
|
563 | in scalar context only the first one will be returned. |
355 | |
564 | |
356 | Not all event models support a blocking wait - some die in that case |
565 | Not all event models support a blocking wait - some die in that case |
357 | (programs might want to do that to stay interactive), so I<if you are |
566 | (programs might want to do that to stay interactive), so I<if you are |
358 | using this from a module, never require a blocking wait>, but let the |
567 | using this from a module, never require a blocking wait>, but let the |
359 | caller decide whether the call will block or not (for example, by coupling |
568 | caller decide whether the call will block or not (for example, by coupling |
360 | condition variables with some kind of request results and supporting |
569 | condition variables with some kind of request results and supporting |
361 | callbacks so the caller knows that getting the result will not block, |
570 | callbacks so the caller knows that getting the result will not block, |
362 | while still suppporting blocking waits if the caller so desires). |
571 | while still supporting blocking waits if the caller so desires). |
363 | |
572 | |
364 | Another reason I<never> to C<< ->wait >> in a module is that you cannot |
573 | Another reason I<never> to C<< ->recv >> in a module is that you cannot |
365 | sensibly have two C<< ->wait >>'s in parallel, as that would require |
574 | sensibly have two C<< ->recv >>'s in parallel, as that would require |
366 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
575 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
367 | can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and |
576 | can supply. |
368 | L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s |
|
|
369 | from different coroutines, however). |
|
|
370 | |
577 | |
371 | =item $cv->broadcast |
578 | The L<Coro> module, however, I<can> and I<does> supply coroutines and, in |
|
|
579 | fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe |
|
|
580 | versions and also integrates coroutines into AnyEvent, making blocking |
|
|
581 | C<< ->recv >> calls perfectly safe as long as they are done from another |
|
|
582 | coroutine (one that doesn't run the event loop). |
372 | |
583 | |
373 | Flag the condition as ready - a running C<< ->wait >> and all further |
584 | You can ensure that C<< -recv >> never blocks by setting a callback and |
374 | calls to C<wait> will (eventually) return after this method has been |
585 | only calling C<< ->recv >> from within that callback (or at a later |
375 | called. If nobody is waiting the broadcast will be remembered.. |
586 | time). This will work even when the event loop does not support blocking |
|
|
587 | waits otherwise. |
|
|
588 | |
|
|
589 | =item $bool = $cv->ready |
|
|
590 | |
|
|
591 | Returns true when the condition is "true", i.e. whether C<send> or |
|
|
592 | C<croak> have been called. |
|
|
593 | |
|
|
594 | =item $cb = $cv->cb ([new callback]) |
|
|
595 | |
|
|
596 | This is a mutator function that returns the callback set and optionally |
|
|
597 | replaces it before doing so. |
|
|
598 | |
|
|
599 | The callback will be called when the condition becomes "true", i.e. when |
|
|
600 | C<send> or C<croak> are called, with the only argument being the condition |
|
|
601 | variable itself. Calling C<recv> inside the callback or at any later time |
|
|
602 | is guaranteed not to block. |
376 | |
603 | |
377 | =back |
604 | =back |
378 | |
|
|
379 | Example: |
|
|
380 | |
|
|
381 | # wait till the result is ready |
|
|
382 | my $result_ready = AnyEvent->condvar; |
|
|
383 | |
|
|
384 | # do something such as adding a timer |
|
|
385 | # or socket watcher the calls $result_ready->broadcast |
|
|
386 | # when the "result" is ready. |
|
|
387 | # in this case, we simply use a timer: |
|
|
388 | my $w = AnyEvent->timer ( |
|
|
389 | after => 1, |
|
|
390 | cb => sub { $result_ready->broadcast }, |
|
|
391 | ); |
|
|
392 | |
|
|
393 | # this "blocks" (while handling events) till the watcher |
|
|
394 | # calls broadcast |
|
|
395 | $result_ready->wait; |
|
|
396 | |
605 | |
397 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
606 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
398 | |
607 | |
399 | =over 4 |
608 | =over 4 |
400 | |
609 | |
… | |
… | |
406 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
615 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
407 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
616 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
408 | |
617 | |
409 | The known classes so far are: |
618 | The known classes so far are: |
410 | |
619 | |
411 | AnyEvent::Impl::CoroEV based on Coro::EV, best choice. |
|
|
412 | AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice. |
|
|
413 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
620 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
414 | AnyEvent::Impl::Event based on Event, second best choice. |
621 | AnyEvent::Impl::Event based on Event, second best choice. |
|
|
622 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
415 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
623 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
416 | AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable. |
|
|
417 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
624 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
418 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
625 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
419 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
626 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
420 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
627 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
421 | |
628 | |
… | |
… | |
434 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
641 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
435 | if necessary. You should only call this function right before you would |
642 | if necessary. You should only call this function right before you would |
436 | have created an AnyEvent watcher anyway, that is, as late as possible at |
643 | have created an AnyEvent watcher anyway, that is, as late as possible at |
437 | runtime. |
644 | runtime. |
438 | |
645 | |
|
|
646 | =item $guard = AnyEvent::post_detect { BLOCK } |
|
|
647 | |
|
|
648 | Arranges for the code block to be executed as soon as the event model is |
|
|
649 | autodetected (or immediately if this has already happened). |
|
|
650 | |
|
|
651 | If called in scalar or list context, then it creates and returns an object |
|
|
652 | that automatically removes the callback again when it is destroyed. See |
|
|
653 | L<Coro::BDB> for a case where this is useful. |
|
|
654 | |
|
|
655 | =item @AnyEvent::post_detect |
|
|
656 | |
|
|
657 | If there are any code references in this array (you can C<push> to it |
|
|
658 | before or after loading AnyEvent), then they will called directly after |
|
|
659 | the event loop has been chosen. |
|
|
660 | |
|
|
661 | You should check C<$AnyEvent::MODEL> before adding to this array, though: |
|
|
662 | if it contains a true value then the event loop has already been detected, |
|
|
663 | and the array will be ignored. |
|
|
664 | |
|
|
665 | Best use C<AnyEvent::post_detect { BLOCK }> instead. |
|
|
666 | |
439 | =back |
667 | =back |
440 | |
668 | |
441 | =head1 WHAT TO DO IN A MODULE |
669 | =head1 WHAT TO DO IN A MODULE |
442 | |
670 | |
443 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
671 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
… | |
… | |
446 | Be careful when you create watchers in the module body - AnyEvent will |
674 | Be careful when you create watchers in the module body - AnyEvent will |
447 | decide which event module to use as soon as the first method is called, so |
675 | decide which event module to use as soon as the first method is called, so |
448 | by calling AnyEvent in your module body you force the user of your module |
676 | by calling AnyEvent in your module body you force the user of your module |
449 | to load the event module first. |
677 | to load the event module first. |
450 | |
678 | |
451 | Never call C<< ->wait >> on a condition variable unless you I<know> that |
679 | Never call C<< ->recv >> on a condition variable unless you I<know> that |
452 | the C<< ->broadcast >> method has been called on it already. This is |
680 | the C<< ->send >> method has been called on it already. This is |
453 | because it will stall the whole program, and the whole point of using |
681 | because it will stall the whole program, and the whole point of using |
454 | events is to stay interactive. |
682 | events is to stay interactive. |
455 | |
683 | |
456 | It is fine, however, to call C<< ->wait >> when the user of your module |
684 | It is fine, however, to call C<< ->recv >> when the user of your module |
457 | requests it (i.e. if you create a http request object ad have a method |
685 | requests it (i.e. if you create a http request object ad have a method |
458 | called C<results> that returns the results, it should call C<< ->wait >> |
686 | called C<results> that returns the results, it should call C<< ->recv >> |
459 | freely, as the user of your module knows what she is doing. always). |
687 | freely, as the user of your module knows what she is doing. always). |
460 | |
688 | |
461 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
689 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
462 | |
690 | |
463 | There will always be a single main program - the only place that should |
691 | There will always be a single main program - the only place that should |
… | |
… | |
465 | |
693 | |
466 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
694 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
467 | do anything special (it does not need to be event-based) and let AnyEvent |
695 | do anything special (it does not need to be event-based) and let AnyEvent |
468 | decide which implementation to chose if some module relies on it. |
696 | decide which implementation to chose if some module relies on it. |
469 | |
697 | |
470 | If the main program relies on a specific event model. For example, in |
698 | If the main program relies on a specific event model - for example, in |
471 | Gtk2 programs you have to rely on the Glib module. You should load the |
699 | Gtk2 programs you have to rely on the Glib module - you should load the |
472 | event module before loading AnyEvent or any module that uses it: generally |
700 | event module before loading AnyEvent or any module that uses it: generally |
473 | speaking, you should load it as early as possible. The reason is that |
701 | speaking, you should load it as early as possible. The reason is that |
474 | modules might create watchers when they are loaded, and AnyEvent will |
702 | modules might create watchers when they are loaded, and AnyEvent will |
475 | decide on the event model to use as soon as it creates watchers, and it |
703 | decide on the event model to use as soon as it creates watchers, and it |
476 | might chose the wrong one unless you load the correct one yourself. |
704 | might chose the wrong one unless you load the correct one yourself. |
477 | |
705 | |
478 | You can chose to use a rather inefficient pure-perl implementation by |
706 | You can chose to use a pure-perl implementation by loading the |
479 | loading the C<AnyEvent::Impl::Perl> module, which gives you similar |
707 | C<AnyEvent::Impl::Perl> module, which gives you similar behaviour |
480 | behaviour everywhere, but letting AnyEvent chose is generally better. |
708 | everywhere, but letting AnyEvent chose the model is generally better. |
|
|
709 | |
|
|
710 | =head2 MAINLOOP EMULATION |
|
|
711 | |
|
|
712 | Sometimes (often for short test scripts, or even standalone programs who |
|
|
713 | only want to use AnyEvent), you do not want to run a specific event loop. |
|
|
714 | |
|
|
715 | In that case, you can use a condition variable like this: |
|
|
716 | |
|
|
717 | AnyEvent->condvar->recv; |
|
|
718 | |
|
|
719 | This has the effect of entering the event loop and looping forever. |
|
|
720 | |
|
|
721 | Note that usually your program has some exit condition, in which case |
|
|
722 | it is better to use the "traditional" approach of storing a condition |
|
|
723 | variable somewhere, waiting for it, and sending it when the program should |
|
|
724 | exit cleanly. |
|
|
725 | |
481 | |
726 | |
482 | =head1 OTHER MODULES |
727 | =head1 OTHER MODULES |
483 | |
728 | |
484 | L<AnyEvent> itself comes with useful utility modules: |
729 | The following is a non-exhaustive list of additional modules that use |
485 | |
730 | AnyEvent and can therefore be mixed easily with other AnyEvent modules |
486 | To make it easier to do non-blocking IO the modules L<AnyEvent::Handle> |
731 | in the same program. Some of the modules come with AnyEvent, some are |
487 | and L<AnyEvent::Socket> are provided. L<AnyEvent::Handle> provides |
732 | available via CPAN. |
488 | read and write buffers and manages watchers for reads and writes. |
|
|
489 | L<AnyEvent::Socket> provides means to do non-blocking connects. |
|
|
490 | |
|
|
491 | Aside from those there are these modules that support AnyEvent (and use it |
|
|
492 | for non-blocking IO): |
|
|
493 | |
733 | |
494 | =over 4 |
734 | =over 4 |
495 | |
735 | |
|
|
736 | =item L<AnyEvent::Util> |
|
|
737 | |
|
|
738 | Contains various utility functions that replace often-used but blocking |
|
|
739 | functions such as C<inet_aton> by event-/callback-based versions. |
|
|
740 | |
|
|
741 | =item L<AnyEvent::Socket> |
|
|
742 | |
|
|
743 | Provides various utility functions for (internet protocol) sockets, |
|
|
744 | addresses and name resolution. Also functions to create non-blocking tcp |
|
|
745 | connections or tcp servers, with IPv6 and SRV record support and more. |
|
|
746 | |
|
|
747 | =item L<AnyEvent::Handle> |
|
|
748 | |
|
|
749 | Provide read and write buffers, manages watchers for reads and writes, |
|
|
750 | supports raw and formatted I/O, I/O queued and fully transparent and |
|
|
751 | non-blocking SSL/TLS. |
|
|
752 | |
|
|
753 | =item L<AnyEvent::DNS> |
|
|
754 | |
|
|
755 | Provides rich asynchronous DNS resolver capabilities. |
|
|
756 | |
|
|
757 | =item L<AnyEvent::HTTP> |
|
|
758 | |
|
|
759 | A simple-to-use HTTP library that is capable of making a lot of concurrent |
|
|
760 | HTTP requests. |
|
|
761 | |
|
|
762 | =item L<AnyEvent::HTTPD> |
|
|
763 | |
|
|
764 | Provides a simple web application server framework. |
|
|
765 | |
496 | =item L<AnyEvent::FastPing> |
766 | =item L<AnyEvent::FastPing> |
497 | |
767 | |
|
|
768 | The fastest ping in the west. |
|
|
769 | |
|
|
770 | =item L<AnyEvent::DBI> |
|
|
771 | |
|
|
772 | Executes L<DBI> requests asynchronously in a proxy process. |
|
|
773 | |
|
|
774 | =item L<AnyEvent::AIO> |
|
|
775 | |
|
|
776 | Truly asynchronous I/O, should be in the toolbox of every event |
|
|
777 | programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent |
|
|
778 | together. |
|
|
779 | |
|
|
780 | =item L<AnyEvent::BDB> |
|
|
781 | |
|
|
782 | Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses |
|
|
783 | L<BDB> and AnyEvent together. |
|
|
784 | |
|
|
785 | =item L<AnyEvent::GPSD> |
|
|
786 | |
|
|
787 | A non-blocking interface to gpsd, a daemon delivering GPS information. |
|
|
788 | |
|
|
789 | =item L<AnyEvent::IGS> |
|
|
790 | |
|
|
791 | A non-blocking interface to the Internet Go Server protocol (used by |
|
|
792 | L<App::IGS>). |
|
|
793 | |
498 | =item L<Net::IRC3> |
794 | =item L<Net::IRC3> |
499 | |
795 | |
|
|
796 | AnyEvent based IRC client module family. |
|
|
797 | |
500 | =item L<Net::XMPP2> |
798 | =item L<Net::XMPP2> |
|
|
799 | |
|
|
800 | AnyEvent based XMPP (Jabber protocol) module family. |
|
|
801 | |
|
|
802 | =item L<Net::FCP> |
|
|
803 | |
|
|
804 | AnyEvent-based implementation of the Freenet Client Protocol, birthplace |
|
|
805 | of AnyEvent. |
|
|
806 | |
|
|
807 | =item L<Event::ExecFlow> |
|
|
808 | |
|
|
809 | High level API for event-based execution flow control. |
|
|
810 | |
|
|
811 | =item L<Coro> |
|
|
812 | |
|
|
813 | Has special support for AnyEvent via L<Coro::AnyEvent>. |
|
|
814 | |
|
|
815 | =item L<IO::Lambda> |
|
|
816 | |
|
|
817 | The lambda approach to I/O - don't ask, look there. Can use AnyEvent. |
501 | |
818 | |
502 | =back |
819 | =back |
503 | |
820 | |
504 | =cut |
821 | =cut |
505 | |
822 | |
… | |
… | |
508 | no warnings; |
825 | no warnings; |
509 | use strict; |
826 | use strict; |
510 | |
827 | |
511 | use Carp; |
828 | use Carp; |
512 | |
829 | |
513 | our $VERSION = '3.3'; |
830 | our $VERSION = 4.2; |
514 | our $MODEL; |
831 | our $MODEL; |
515 | |
832 | |
516 | our $AUTOLOAD; |
833 | our $AUTOLOAD; |
517 | our @ISA; |
834 | our @ISA; |
518 | |
835 | |
|
|
836 | our @REGISTRY; |
|
|
837 | |
|
|
838 | our $WIN32; |
|
|
839 | |
|
|
840 | BEGIN { |
|
|
841 | my $win32 = ! ! ($^O =~ /mswin32/i); |
|
|
842 | eval "sub WIN32(){ $win32 }"; |
|
|
843 | } |
|
|
844 | |
519 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
845 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
520 | |
846 | |
521 | our @REGISTRY; |
847 | our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred |
|
|
848 | |
|
|
849 | { |
|
|
850 | my $idx; |
|
|
851 | $PROTOCOL{$_} = ++$idx |
|
|
852 | for reverse split /\s*,\s*/, |
|
|
853 | $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; |
|
|
854 | } |
522 | |
855 | |
523 | my @models = ( |
856 | my @models = ( |
524 | [Coro::EV:: => AnyEvent::Impl::CoroEV::], |
|
|
525 | [Coro::Event:: => AnyEvent::Impl::CoroEvent::], |
|
|
526 | [EV:: => AnyEvent::Impl::EV::], |
857 | [EV:: => AnyEvent::Impl::EV::], |
527 | [Event:: => AnyEvent::Impl::Event::], |
858 | [Event:: => AnyEvent::Impl::Event::], |
528 | [Glib:: => AnyEvent::Impl::Glib::], |
|
|
529 | [Tk:: => AnyEvent::Impl::Tk::], |
|
|
530 | [Wx:: => AnyEvent::Impl::POE::], |
|
|
531 | [Prima:: => AnyEvent::Impl::POE::], |
|
|
532 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
859 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
533 | # everything below here will not be autoprobed as the pureperl backend should work everywhere |
860 | # everything below here will not be autoprobed |
|
|
861 | # as the pureperl backend should work everywhere |
|
|
862 | # and is usually faster |
|
|
863 | [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles |
|
|
864 | [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers |
534 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
865 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
535 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
866 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
536 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
867 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
|
|
868 | [Wx:: => AnyEvent::Impl::POE::], |
|
|
869 | [Prima:: => AnyEvent::Impl::POE::], |
537 | ); |
870 | ); |
538 | |
871 | |
539 | our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY); |
872 | our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY); |
|
|
873 | |
|
|
874 | our @post_detect; |
|
|
875 | |
|
|
876 | sub post_detect(&) { |
|
|
877 | my ($cb) = @_; |
|
|
878 | |
|
|
879 | if ($MODEL) { |
|
|
880 | $cb->(); |
|
|
881 | |
|
|
882 | 1 |
|
|
883 | } else { |
|
|
884 | push @post_detect, $cb; |
|
|
885 | |
|
|
886 | defined wantarray |
|
|
887 | ? bless \$cb, "AnyEvent::Util::PostDetect" |
|
|
888 | : () |
|
|
889 | } |
|
|
890 | } |
|
|
891 | |
|
|
892 | sub AnyEvent::Util::PostDetect::DESTROY { |
|
|
893 | @post_detect = grep $_ != ${$_[0]}, @post_detect; |
|
|
894 | } |
540 | |
895 | |
541 | sub detect() { |
896 | sub detect() { |
542 | unless ($MODEL) { |
897 | unless ($MODEL) { |
543 | no strict 'refs'; |
898 | no strict 'refs'; |
|
|
899 | local $SIG{__DIE__}; |
544 | |
900 | |
545 | if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { |
901 | if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { |
546 | my $model = "AnyEvent::Impl::$1"; |
902 | my $model = "AnyEvent::Impl::$1"; |
547 | if (eval "require $model") { |
903 | if (eval "require $model") { |
548 | $MODEL = $model; |
904 | $MODEL = $model; |
… | |
… | |
578 | last; |
934 | last; |
579 | } |
935 | } |
580 | } |
936 | } |
581 | |
937 | |
582 | $MODEL |
938 | $MODEL |
583 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib."; |
939 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib."; |
584 | } |
940 | } |
585 | } |
941 | } |
586 | |
942 | |
587 | unshift @ISA, $MODEL; |
943 | unshift @ISA, $MODEL; |
588 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
944 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
|
|
945 | |
|
|
946 | (shift @post_detect)->() while @post_detect; |
589 | } |
947 | } |
590 | |
948 | |
591 | $MODEL |
949 | $MODEL |
592 | } |
950 | } |
593 | |
951 | |
… | |
… | |
603 | $class->$func (@_); |
961 | $class->$func (@_); |
604 | } |
962 | } |
605 | |
963 | |
606 | package AnyEvent::Base; |
964 | package AnyEvent::Base; |
607 | |
965 | |
|
|
966 | # default implementation for now and time |
|
|
967 | |
|
|
968 | use Time::HiRes (); |
|
|
969 | |
|
|
970 | sub time { Time::HiRes::time } |
|
|
971 | sub now { Time::HiRes::time } |
|
|
972 | |
608 | # default implementation for ->condvar, ->wait, ->broadcast |
973 | # default implementation for ->condvar |
609 | |
974 | |
610 | sub condvar { |
975 | sub condvar { |
611 | bless \my $flag, "AnyEvent::Base::CondVar" |
976 | bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: |
612 | } |
|
|
613 | |
|
|
614 | sub AnyEvent::Base::CondVar::broadcast { |
|
|
615 | ${$_[0]}++; |
|
|
616 | } |
|
|
617 | |
|
|
618 | sub AnyEvent::Base::CondVar::wait { |
|
|
619 | AnyEvent->one_event while !${$_[0]}; |
|
|
620 | } |
977 | } |
621 | |
978 | |
622 | # default implementation for ->signal |
979 | # default implementation for ->signal |
623 | |
980 | |
624 | our %SIG_CB; |
981 | our %SIG_CB; |
… | |
… | |
640 | sub AnyEvent::Base::Signal::DESTROY { |
997 | sub AnyEvent::Base::Signal::DESTROY { |
641 | my ($signal, $cb) = @{$_[0]}; |
998 | my ($signal, $cb) = @{$_[0]}; |
642 | |
999 | |
643 | delete $SIG_CB{$signal}{$cb}; |
1000 | delete $SIG_CB{$signal}{$cb}; |
644 | |
1001 | |
645 | $SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} }; |
1002 | delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} }; |
646 | } |
1003 | } |
647 | |
1004 | |
648 | # default implementation for ->child |
1005 | # default implementation for ->child |
649 | |
1006 | |
650 | our %PID_CB; |
1007 | our %PID_CB; |
… | |
… | |
677 | or Carp::croak "required option 'pid' is missing"; |
1034 | or Carp::croak "required option 'pid' is missing"; |
678 | |
1035 | |
679 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
1036 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
680 | |
1037 | |
681 | unless ($WNOHANG) { |
1038 | unless ($WNOHANG) { |
682 | $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1; |
1039 | $WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; |
683 | } |
1040 | } |
684 | |
1041 | |
685 | unless ($CHLD_W) { |
1042 | unless ($CHLD_W) { |
686 | $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); |
1043 | $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); |
687 | # child could be a zombie already, so make at least one round |
1044 | # child could be a zombie already, so make at least one round |
… | |
… | |
697 | delete $PID_CB{$pid}{$cb}; |
1054 | delete $PID_CB{$pid}{$cb}; |
698 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
1055 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
699 | |
1056 | |
700 | undef $CHLD_W unless keys %PID_CB; |
1057 | undef $CHLD_W unless keys %PID_CB; |
701 | } |
1058 | } |
|
|
1059 | |
|
|
1060 | package AnyEvent::CondVar; |
|
|
1061 | |
|
|
1062 | our @ISA = AnyEvent::CondVar::Base::; |
|
|
1063 | |
|
|
1064 | package AnyEvent::CondVar::Base; |
|
|
1065 | |
|
|
1066 | use overload |
|
|
1067 | '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, |
|
|
1068 | fallback => 1; |
|
|
1069 | |
|
|
1070 | sub _send { |
|
|
1071 | # nop |
|
|
1072 | } |
|
|
1073 | |
|
|
1074 | sub send { |
|
|
1075 | my $cv = shift; |
|
|
1076 | $cv->{_ae_sent} = [@_]; |
|
|
1077 | (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb}; |
|
|
1078 | $cv->_send; |
|
|
1079 | } |
|
|
1080 | |
|
|
1081 | sub croak { |
|
|
1082 | $_[0]{_ae_croak} = $_[1]; |
|
|
1083 | $_[0]->send; |
|
|
1084 | } |
|
|
1085 | |
|
|
1086 | sub ready { |
|
|
1087 | $_[0]{_ae_sent} |
|
|
1088 | } |
|
|
1089 | |
|
|
1090 | sub _wait { |
|
|
1091 | AnyEvent->one_event while !$_[0]{_ae_sent}; |
|
|
1092 | } |
|
|
1093 | |
|
|
1094 | sub recv { |
|
|
1095 | $_[0]->_wait; |
|
|
1096 | |
|
|
1097 | Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; |
|
|
1098 | wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] |
|
|
1099 | } |
|
|
1100 | |
|
|
1101 | sub cb { |
|
|
1102 | $_[0]{_ae_cb} = $_[1] if @_ > 1; |
|
|
1103 | $_[0]{_ae_cb} |
|
|
1104 | } |
|
|
1105 | |
|
|
1106 | sub begin { |
|
|
1107 | ++$_[0]{_ae_counter}; |
|
|
1108 | $_[0]{_ae_end_cb} = $_[1] if @_ > 1; |
|
|
1109 | } |
|
|
1110 | |
|
|
1111 | sub end { |
|
|
1112 | return if --$_[0]{_ae_counter}; |
|
|
1113 | &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } }; |
|
|
1114 | } |
|
|
1115 | |
|
|
1116 | # undocumented/compatibility with pre-3.4 |
|
|
1117 | *broadcast = \&send; |
|
|
1118 | *wait = \&_wait; |
702 | |
1119 | |
703 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
1120 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
704 | |
1121 | |
705 | This is an advanced topic that you do not normally need to use AnyEvent in |
1122 | This is an advanced topic that you do not normally need to use AnyEvent in |
706 | a module. This section is only of use to event loop authors who want to |
1123 | a module. This section is only of use to event loop authors who want to |
… | |
… | |
763 | model it chooses. |
1180 | model it chooses. |
764 | |
1181 | |
765 | =item C<PERL_ANYEVENT_MODEL> |
1182 | =item C<PERL_ANYEVENT_MODEL> |
766 | |
1183 | |
767 | This can be used to specify the event model to be used by AnyEvent, before |
1184 | This can be used to specify the event model to be used by AnyEvent, before |
768 | autodetection and -probing kicks in. It must be a string consisting |
1185 | auto detection and -probing kicks in. It must be a string consisting |
769 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
1186 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
770 | and the resulting module name is loaded and if the load was successful, |
1187 | and the resulting module name is loaded and if the load was successful, |
771 | used as event model. If it fails to load AnyEvent will proceed with |
1188 | used as event model. If it fails to load AnyEvent will proceed with |
772 | autodetection and -probing. |
1189 | auto detection and -probing. |
773 | |
1190 | |
774 | This functionality might change in future versions. |
1191 | This functionality might change in future versions. |
775 | |
1192 | |
776 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
1193 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
777 | could start your program like this: |
1194 | could start your program like this: |
778 | |
1195 | |
779 | PERL_ANYEVENT_MODEL=Perl perl ... |
1196 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
1197 | |
|
|
1198 | =item C<PERL_ANYEVENT_PROTOCOLS> |
|
|
1199 | |
|
|
1200 | Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences |
|
|
1201 | for IPv4 or IPv6. The default is unspecified (and might change, or be the result |
|
|
1202 | of auto probing). |
|
|
1203 | |
|
|
1204 | Must be set to a comma-separated list of protocols or address families, |
|
|
1205 | current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be |
|
|
1206 | used, and preference will be given to protocols mentioned earlier in the |
|
|
1207 | list. |
|
|
1208 | |
|
|
1209 | This variable can effectively be used for denial-of-service attacks |
|
|
1210 | against local programs (e.g. when setuid), although the impact is likely |
|
|
1211 | small, as the program has to handle connection errors already- |
|
|
1212 | |
|
|
1213 | Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6, |
|
|
1214 | but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> |
|
|
1215 | - only support IPv4, never try to resolve or contact IPv6 |
|
|
1216 | addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or |
|
|
1217 | IPv6, but prefer IPv6 over IPv4. |
|
|
1218 | |
|
|
1219 | =item C<PERL_ANYEVENT_EDNS0> |
|
|
1220 | |
|
|
1221 | Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension |
|
|
1222 | for DNS. This extension is generally useful to reduce DNS traffic, but |
|
|
1223 | some (broken) firewalls drop such DNS packets, which is why it is off by |
|
|
1224 | default. |
|
|
1225 | |
|
|
1226 | Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce |
|
|
1227 | EDNS0 in its DNS requests. |
|
|
1228 | |
|
|
1229 | =item C<PERL_ANYEVENT_MAX_FORKS> |
|
|
1230 | |
|
|
1231 | The maximum number of child processes that C<AnyEvent::Util::fork_call> |
|
|
1232 | will create in parallel. |
780 | |
1233 | |
781 | =back |
1234 | =back |
782 | |
1235 | |
783 | =head1 EXAMPLE PROGRAM |
1236 | =head1 EXAMPLE PROGRAM |
784 | |
1237 | |
… | |
… | |
795 | poll => 'r', |
1248 | poll => 'r', |
796 | cb => sub { |
1249 | cb => sub { |
797 | warn "io event <$_[0]>\n"; # will always output <r> |
1250 | warn "io event <$_[0]>\n"; # will always output <r> |
798 | chomp (my $input = <STDIN>); # read a line |
1251 | chomp (my $input = <STDIN>); # read a line |
799 | warn "read: $input\n"; # output what has been read |
1252 | warn "read: $input\n"; # output what has been read |
800 | $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i |
1253 | $cv->send if $input =~ /^q/i; # quit program if /^q/i |
801 | }, |
1254 | }, |
802 | ); |
1255 | ); |
803 | |
1256 | |
804 | my $time_watcher; # can only be used once |
1257 | my $time_watcher; # can only be used once |
805 | |
1258 | |
… | |
… | |
810 | }); |
1263 | }); |
811 | } |
1264 | } |
812 | |
1265 | |
813 | new_timer; # create first timer |
1266 | new_timer; # create first timer |
814 | |
1267 | |
815 | $cv->wait; # wait until user enters /^q/i |
1268 | $cv->recv; # wait until user enters /^q/i |
816 | |
1269 | |
817 | =head1 REAL-WORLD EXAMPLE |
1270 | =head1 REAL-WORLD EXAMPLE |
818 | |
1271 | |
819 | Consider the L<Net::FCP> module. It features (among others) the following |
1272 | Consider the L<Net::FCP> module. It features (among others) the following |
820 | API calls, which are to freenet what HTTP GET requests are to http: |
1273 | API calls, which are to freenet what HTTP GET requests are to http: |
… | |
… | |
870 | syswrite $txn->{fh}, $txn->{request} |
1323 | syswrite $txn->{fh}, $txn->{request} |
871 | or die "connection or write error"; |
1324 | or die "connection or write error"; |
872 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
1325 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
873 | |
1326 | |
874 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
1327 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
875 | result and signals any possible waiters that the request ahs finished: |
1328 | result and signals any possible waiters that the request has finished: |
876 | |
1329 | |
877 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
1330 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
878 | |
1331 | |
879 | if (end-of-file or data complete) { |
1332 | if (end-of-file or data complete) { |
880 | $txn->{result} = $txn->{buf}; |
1333 | $txn->{result} = $txn->{buf}; |
881 | $txn->{finished}->broadcast; |
1334 | $txn->{finished}->send; |
882 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
1335 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
883 | } |
1336 | } |
884 | |
1337 | |
885 | The C<result> method, finally, just waits for the finished signal (if the |
1338 | The C<result> method, finally, just waits for the finished signal (if the |
886 | request was already finished, it doesn't wait, of course, and returns the |
1339 | request was already finished, it doesn't wait, of course, and returns the |
887 | data: |
1340 | data: |
888 | |
1341 | |
889 | $txn->{finished}->wait; |
1342 | $txn->{finished}->recv; |
890 | return $txn->{result}; |
1343 | return $txn->{result}; |
891 | |
1344 | |
892 | The actual code goes further and collects all errors (C<die>s, exceptions) |
1345 | The actual code goes further and collects all errors (C<die>s, exceptions) |
893 | that occured during request processing. The C<result> method detects |
1346 | that occurred during request processing. The C<result> method detects |
894 | whether an exception as thrown (it is stored inside the $txn object) |
1347 | whether an exception as thrown (it is stored inside the $txn object) |
895 | and just throws the exception, which means connection errors and other |
1348 | and just throws the exception, which means connection errors and other |
896 | problems get reported tot he code that tries to use the result, not in a |
1349 | problems get reported tot he code that tries to use the result, not in a |
897 | random callback. |
1350 | random callback. |
898 | |
1351 | |
… | |
… | |
929 | |
1382 | |
930 | my $quit = AnyEvent->condvar; |
1383 | my $quit = AnyEvent->condvar; |
931 | |
1384 | |
932 | $fcp->txn_client_get ($url)->cb (sub { |
1385 | $fcp->txn_client_get ($url)->cb (sub { |
933 | ... |
1386 | ... |
934 | $quit->broadcast; |
1387 | $quit->send; |
935 | }); |
1388 | }); |
936 | |
1389 | |
937 | $quit->wait; |
1390 | $quit->recv; |
938 | |
1391 | |
939 | |
1392 | |
940 | =head1 BENCHMARKS |
1393 | =head1 BENCHMARKS |
941 | |
1394 | |
942 | To give you an idea of the performance and overheads that AnyEvent adds |
1395 | To give you an idea of the performance and overheads that AnyEvent adds |
… | |
… | |
944 | of various event loops I prepared some benchmarks. |
1397 | of various event loops I prepared some benchmarks. |
945 | |
1398 | |
946 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
1399 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
947 | |
1400 | |
948 | Here is a benchmark of various supported event models used natively and |
1401 | Here is a benchmark of various supported event models used natively and |
949 | through anyevent. The benchmark creates a lot of timers (with a zero |
1402 | through AnyEvent. The benchmark creates a lot of timers (with a zero |
950 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
1403 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
951 | which it is), lets them fire exactly once and destroys them again. |
1404 | which it is), lets them fire exactly once and destroys them again. |
952 | |
1405 | |
953 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
1406 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
954 | distribution. |
1407 | distribution. |
… | |
… | |
971 | all watchers, to avoid adding memory overhead. That means closure creation |
1424 | all watchers, to avoid adding memory overhead. That means closure creation |
972 | and memory usage is not included in the figures. |
1425 | and memory usage is not included in the figures. |
973 | |
1426 | |
974 | I<invoke> is the time, in microseconds, used to invoke a simple |
1427 | I<invoke> is the time, in microseconds, used to invoke a simple |
975 | callback. The callback simply counts down a Perl variable and after it was |
1428 | callback. The callback simply counts down a Perl variable and after it was |
976 | invoked "watcher" times, it would C<< ->broadcast >> a condvar once to |
1429 | invoked "watcher" times, it would C<< ->send >> a condvar once to |
977 | signal the end of this phase. |
1430 | signal the end of this phase. |
978 | |
1431 | |
979 | I<destroy> is the time, in microseconds, that it takes to destroy a single |
1432 | I<destroy> is the time, in microseconds, that it takes to destroy a single |
980 | watcher. |
1433 | watcher. |
981 | |
1434 | |
… | |
… | |
1041 | file descriptor is dup()ed for each watcher. This shows that the dup() |
1494 | file descriptor is dup()ed for each watcher. This shows that the dup() |
1042 | employed by some adaptors is not a big performance issue (it does incur a |
1495 | employed by some adaptors is not a big performance issue (it does incur a |
1043 | hidden memory cost inside the kernel which is not reflected in the figures |
1496 | hidden memory cost inside the kernel which is not reflected in the figures |
1044 | above). |
1497 | above). |
1045 | |
1498 | |
1046 | C<POE>, regardless of underlying event loop (whether using its pure |
1499 | C<POE>, regardless of underlying event loop (whether using its pure perl |
1047 | perl select-based backend or the Event module, the POE-EV backend |
1500 | select-based backend or the Event module, the POE-EV backend couldn't |
1048 | couldn't be tested because it wasn't working) shows abysmal performance |
1501 | be tested because it wasn't working) shows abysmal performance and |
1049 | and memory usage: Watchers use almost 30 times as much memory as |
1502 | memory usage with AnyEvent: Watchers use almost 30 times as much memory |
1050 | EV watchers, and 10 times as much memory as Event (the high memory |
1503 | as EV watchers, and 10 times as much memory as Event (the high memory |
1051 | requirements are caused by requiring a session for each watcher). Watcher |
1504 | requirements are caused by requiring a session for each watcher). Watcher |
1052 | invocation speed is almost 900 times slower than with AnyEvent's pure perl |
1505 | invocation speed is almost 900 times slower than with AnyEvent's pure perl |
|
|
1506 | implementation. |
|
|
1507 | |
1053 | implementation. The design of the POE adaptor class in AnyEvent can not |
1508 | The design of the POE adaptor class in AnyEvent can not really account |
1054 | really account for this, as session creation overhead is small compared |
1509 | for the performance issues, though, as session creation overhead is |
1055 | to execution of the state machine, which is coded pretty optimally within |
1510 | small compared to execution of the state machine, which is coded pretty |
1056 | L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow. |
1511 | optimally within L<AnyEvent::Impl::POE> (and while everybody agrees that |
|
|
1512 | using multiple sessions is not a good approach, especially regarding |
|
|
1513 | memory usage, even the author of POE could not come up with a faster |
|
|
1514 | design). |
1057 | |
1515 | |
1058 | =head3 Summary |
1516 | =head3 Summary |
1059 | |
1517 | |
1060 | =over 4 |
1518 | =over 4 |
1061 | |
1519 | |
… | |
… | |
1072 | |
1530 | |
1073 | =back |
1531 | =back |
1074 | |
1532 | |
1075 | =head2 BENCHMARKING THE LARGE SERVER CASE |
1533 | =head2 BENCHMARKING THE LARGE SERVER CASE |
1076 | |
1534 | |
1077 | This benchmark atcually benchmarks the event loop itself. It works by |
1535 | This benchmark actually benchmarks the event loop itself. It works by |
1078 | creating a number of "servers": each server consists of a socketpair, a |
1536 | creating a number of "servers": each server consists of a socket pair, a |
1079 | timeout watcher that gets reset on activity (but never fires), and an I/O |
1537 | timeout watcher that gets reset on activity (but never fires), and an I/O |
1080 | watcher waiting for input on one side of the socket. Each time the socket |
1538 | watcher waiting for input on one side of the socket. Each time the socket |
1081 | watcher reads a byte it will write that byte to a random other "server". |
1539 | watcher reads a byte it will write that byte to a random other "server". |
1082 | |
1540 | |
1083 | The effect is that there will be a lot of I/O watchers, only part of which |
1541 | The effect is that there will be a lot of I/O watchers, only part of which |
1084 | are active at any one point (so there is a constant number of active |
1542 | are active at any one point (so there is a constant number of active |
1085 | fds for each loop iterstaion, but which fds these are is random). The |
1543 | fds for each loop iteration, but which fds these are is random). The |
1086 | timeout is reset each time something is read because that reflects how |
1544 | timeout is reset each time something is read because that reflects how |
1087 | most timeouts work (and puts extra pressure on the event loops). |
1545 | most timeouts work (and puts extra pressure on the event loops). |
1088 | |
1546 | |
1089 | In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100 |
1547 | In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 |
1090 | (1%) are active. This mirrors the activity of large servers with many |
1548 | (1%) are active. This mirrors the activity of large servers with many |
1091 | connections, most of which are idle at any one point in time. |
1549 | connections, most of which are idle at any one point in time. |
1092 | |
1550 | |
1093 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
1551 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
1094 | distribution. |
1552 | distribution. |
… | |
… | |
1096 | =head3 Explanation of the columns |
1554 | =head3 Explanation of the columns |
1097 | |
1555 | |
1098 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
1556 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
1099 | each server has a read and write socket end). |
1557 | each server has a read and write socket end). |
1100 | |
1558 | |
1101 | I<create> is the time it takes to create a socketpair (which is |
1559 | I<create> is the time it takes to create a socket pair (which is |
1102 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
1560 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
1103 | |
1561 | |
1104 | I<request>, the most important value, is the time it takes to handle a |
1562 | I<request>, the most important value, is the time it takes to handle a |
1105 | single "request", that is, reading the token from the pipe and forwarding |
1563 | single "request", that is, reading the token from the pipe and forwarding |
1106 | it to another server. This includes deleting the old timeout and creating |
1564 | it to another server. This includes deleting the old timeout and creating |
… | |
… | |
1140 | |
1598 | |
1141 | =head3 Summary |
1599 | =head3 Summary |
1142 | |
1600 | |
1143 | =over 4 |
1601 | =over 4 |
1144 | |
1602 | |
1145 | =item * The pure perl implementation performs extremely well, considering |
1603 | =item * The pure perl implementation performs extremely well. |
1146 | that it uses select. |
|
|
1147 | |
1604 | |
1148 | =item * Avoid Glib or POE in large projects where performance matters. |
1605 | =item * Avoid Glib or POE in large projects where performance matters. |
1149 | |
1606 | |
1150 | =back |
1607 | =back |
1151 | |
1608 | |
… | |
… | |
1180 | speed most when you have lots of watchers, not when you only have a few of |
1637 | speed most when you have lots of watchers, not when you only have a few of |
1181 | them). |
1638 | them). |
1182 | |
1639 | |
1183 | EV is again fastest. |
1640 | EV is again fastest. |
1184 | |
1641 | |
1185 | The C-based event loops Event and Glib come in second this time, as the |
1642 | Perl again comes second. It is noticeably faster than the C-based event |
1186 | overhead of running an iteration is much smaller in C than in Perl (little |
1643 | loops Event and Glib, although the difference is too small to really |
1187 | code to execute in the inner loop, and perl's function calling overhead is |
1644 | matter. |
1188 | high, and updating all the data structures is costly). |
|
|
1189 | |
|
|
1190 | The pure perl event loop is much slower, but still competitive. |
|
|
1191 | |
1645 | |
1192 | POE also performs much better in this case, but is is still far behind the |
1646 | POE also performs much better in this case, but is is still far behind the |
1193 | others. |
1647 | others. |
1194 | |
1648 | |
1195 | =head3 Summary |
1649 | =head3 Summary |
… | |
… | |
1203 | |
1657 | |
1204 | |
1658 | |
1205 | =head1 FORK |
1659 | =head1 FORK |
1206 | |
1660 | |
1207 | Most event libraries are not fork-safe. The ones who are usually are |
1661 | Most event libraries are not fork-safe. The ones who are usually are |
1208 | because they are so inefficient. Only L<EV> is fully fork-aware. |
1662 | because they rely on inefficient but fork-safe C<select> or C<poll> |
|
|
1663 | calls. Only L<EV> is fully fork-aware. |
1209 | |
1664 | |
1210 | If you have to fork, you must either do so I<before> creating your first |
1665 | If you have to fork, you must either do so I<before> creating your first |
1211 | watcher OR you must not use AnyEvent at all in the child. |
1666 | watcher OR you must not use AnyEvent at all in the child. |
1212 | |
1667 | |
1213 | |
1668 | |
… | |
… | |
1221 | specified in the variable. |
1676 | specified in the variable. |
1222 | |
1677 | |
1223 | You can make AnyEvent completely ignore this variable by deleting it |
1678 | You can make AnyEvent completely ignore this variable by deleting it |
1224 | before the first watcher gets created, e.g. with a C<BEGIN> block: |
1679 | before the first watcher gets created, e.g. with a C<BEGIN> block: |
1225 | |
1680 | |
1226 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
1681 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
1227 | |
1682 | |
1228 | use AnyEvent; |
1683 | use AnyEvent; |
|
|
1684 | |
|
|
1685 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
|
|
1686 | be used to probe what backend is used and gain other information (which is |
|
|
1687 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL). |
|
|
1688 | |
|
|
1689 | |
|
|
1690 | =head1 BUGS |
|
|
1691 | |
|
|
1692 | Perl 5.8 has numerous memleaks that sometimes hit this module and are hard |
|
|
1693 | to work around. If you suffer from memleaks, first upgrade to Perl 5.10 |
|
|
1694 | and check wether the leaks still show up. (Perl 5.10.0 has other annoying |
|
|
1695 | mamleaks, such as leaking on C<map> and C<grep> but it is usually not as |
|
|
1696 | pronounced). |
1229 | |
1697 | |
1230 | |
1698 | |
1231 | =head1 SEE ALSO |
1699 | =head1 SEE ALSO |
1232 | |
1700 | |
1233 | Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>, |
1701 | Utility functions: L<AnyEvent::Util>. |
1234 | L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>, |
1702 | |
|
|
1703 | Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, |
1235 | L<Event::Lib>, L<Qt>, L<POE>. |
1704 | L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. |
1236 | |
1705 | |
1237 | Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>, |
1706 | Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, |
1238 | L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, |
1707 | L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, |
1239 | L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>, |
1708 | L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, |
1240 | L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>. |
1709 | L<AnyEvent::Impl::POE>. |
1241 | |
1710 | |
|
|
1711 | Non-blocking file handles, sockets, TCP clients and |
|
|
1712 | servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. |
|
|
1713 | |
|
|
1714 | Asynchronous DNS: L<AnyEvent::DNS>. |
|
|
1715 | |
|
|
1716 | Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, |
|
|
1717 | |
1242 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. |
1718 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. |
1243 | |
1719 | |
1244 | |
1720 | |
1245 | =head1 AUTHOR |
1721 | =head1 AUTHOR |
1246 | |
1722 | |
1247 | Marc Lehmann <schmorp@schmorp.de> |
1723 | Marc Lehmann <schmorp@schmorp.de> |
1248 | http://home.schmorp.de/ |
1724 | http://home.schmorp.de/ |
1249 | |
1725 | |
1250 | =cut |
1726 | =cut |
1251 | |
1727 | |
1252 | 1 |
1728 | 1 |
1253 | |
1729 | |