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 | Event, Coro, Glib, Tk, Perl - various supported event loops |
5 | EV, Event, Coro::EV, Coro::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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14 | |
14 | |
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 wether a condition was flagged |
19 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
20 | $w->wait; # enters "main loop" till $condvar gets ->broadcast |
20 | $w->wait; # enters "main loop" till $condvar gets ->broadcast |
21 | $w->broadcast; # wake up current and all future wait's |
21 | $w->broadcast; # wake up current and all future wait's |
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22 | |
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23 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
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24 | |
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25 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
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26 | nowadays. So what is different about AnyEvent? |
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27 | |
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28 | Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of |
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29 | policy> and AnyEvent is I<small and efficient>. |
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30 | |
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31 | First and foremost, I<AnyEvent is not an event model> itself, it only |
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32 | interfaces to whatever event model the main program happens to use in a |
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33 | pragmatic way. For event models and certain classes of immortals alike, |
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34 | the statement "there can only be one" is a bitter reality: In general, |
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35 | only one event loop can be active at the same time in a process. AnyEvent |
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36 | helps hiding the differences between those event loops. |
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37 | |
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38 | The goal of AnyEvent is to offer module authors the ability to do event |
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39 | programming (waiting for I/O or timer events) without subscribing to a |
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40 | religion, a way of living, and most importantly: without forcing your |
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41 | module users into the same thing by forcing them to use the same event |
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42 | model you use. |
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43 | |
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44 | For modules like POE or IO::Async (which is a total misnomer as it is |
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45 | actually doing all I/O I<synchronously>...), using them in your module is |
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46 | like joining a cult: After you joined, you are dependent on them and you |
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47 | cannot use anything else, as it is simply incompatible to everything that |
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48 | isn't itself. What's worse, all the potential users of your module are |
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49 | I<also> forced to use the same event loop you use. |
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50 | |
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51 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
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52 | fine. AnyEvent + Tk works fine etc. etc. but none of these work together |
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53 | with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if |
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54 | your module uses one of those, every user of your module has to use it, |
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55 | too. But if your module uses AnyEvent, it works transparently with all |
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56 | event models it supports (including stuff like POE and IO::Async, as long |
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57 | as those use one of the supported event loops. It is trivial to add new |
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58 | event loops to AnyEvent, too, so it is future-proof). |
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59 | |
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60 | In addition to being free of having to use I<the one and only true event |
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61 | model>, AnyEvent also is free of bloat and policy: with POE or similar |
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62 | modules, you get an enourmous amount of code and strict rules you have to |
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63 | follow. AnyEvent, on the other hand, is lean and up to the point, by only |
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64 | offering the functionality that is necessary, in as thin as a wrapper as |
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65 | technically possible. |
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66 | |
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67 | Of course, if you want lots of policy (this can arguably be somewhat |
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68 | useful) and you want to force your users to use the one and only event |
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69 | model, you should I<not> use this module. |
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70 | |
22 | |
71 | |
23 | =head1 DESCRIPTION |
72 | =head1 DESCRIPTION |
24 | |
73 | |
25 | L<AnyEvent> provides an identical interface to multiple event loops. This |
74 | L<AnyEvent> provides an identical interface to multiple event loops. This |
26 | allows module authors to utilise an event loop without forcing module |
75 | allows module authors to utilise an event loop without forcing module |
27 | users to use the same event loop (as only a single event loop can coexist |
76 | users to use the same event loop (as only a single event loop can coexist |
28 | peacefully at any one time). |
77 | peacefully at any one time). |
29 | |
78 | |
30 | The interface itself is vaguely similar but not identical to the Event |
79 | The interface itself is vaguely similar, but not identical to the L<Event> |
31 | module. |
80 | module. |
32 | |
81 | |
33 | On the first call of any method, the module tries to detect the currently |
82 | During the first call of any watcher-creation method, the module tries |
34 | loaded event loop by probing wether any of the following modules is |
83 | to detect the currently loaded event loop by probing whether one of the |
35 | loaded: L<Coro::Event>, L<Event>, L<Glib>, L<Tk>. The first one found is |
84 | following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>, |
36 | used. If none is found, the module tries to load these modules in the |
85 | L<Event>, L<Glib>, L<Tk>, L<AnyEvent::Impl::Perl>, L<Event::Lib>, L<Qt>, |
37 | order given. The first one that could be successfully loaded will be |
86 | L<POE>. The first one found is used. If none are found, the module tries |
38 | used. If still none could be found, AnyEvent will fall back to a pure-perl |
87 | to load these modules (excluding Event::Lib, Qt and POE as the pure perl |
39 | event loop, which is also not very efficient. |
88 | adaptor should always succeed) in the order given. The first one that can |
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89 | be successfully loaded will be used. If, after this, still none could be |
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90 | found, AnyEvent will fall back to a pure-perl event loop, which is not |
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91 | very efficient, but should work everywhere. |
40 | |
92 | |
41 | Because AnyEvent first checks for modules that are already loaded, loading |
93 | Because AnyEvent first checks for modules that are already loaded, loading |
42 | an Event model explicitly before first using AnyEvent will likely make |
94 | an event model explicitly before first using AnyEvent will likely make |
43 | that model the default. For example: |
95 | that model the default. For example: |
44 | |
96 | |
45 | use Tk; |
97 | use Tk; |
46 | use AnyEvent; |
98 | use AnyEvent; |
47 | |
99 | |
48 | # .. AnyEvent will likely default to Tk |
100 | # .. AnyEvent will likely default to Tk |
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101 | |
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102 | The I<likely> means that, if any module loads another event model and |
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103 | starts using it, all bets are off. Maybe you should tell their authors to |
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104 | use AnyEvent so their modules work together with others seamlessly... |
49 | |
105 | |
50 | The pure-perl implementation of AnyEvent is called |
106 | The pure-perl implementation of AnyEvent is called |
51 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
107 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
52 | explicitly. |
108 | explicitly. |
53 | |
109 | |
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56 | AnyEvent has the central concept of a I<watcher>, which is an object that |
112 | AnyEvent has the central concept of a I<watcher>, which is an object that |
57 | stores relevant data for each kind of event you are waiting for, such as |
113 | stores relevant data for each kind of event you are waiting for, such as |
58 | the callback to call, the filehandle to watch, etc. |
114 | the callback to call, the filehandle to watch, etc. |
59 | |
115 | |
60 | These watchers are normal Perl objects with normal Perl lifetime. After |
116 | These watchers are normal Perl objects with normal Perl lifetime. After |
61 | creating a watcher it will immediately "watch" for events and invoke |
117 | creating a watcher it will immediately "watch" for events and invoke the |
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118 | callback when the event occurs (of course, only when the event model |
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119 | is in control). |
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120 | |
62 | the callback. To disable the watcher you have to destroy it (e.g. by |
121 | To disable the watcher you have to destroy it (e.g. by setting the |
63 | setting the variable that stores it to C<undef> or otherwise deleting all |
122 | variable you store it in to C<undef> or otherwise deleting all references |
64 | references to it). |
123 | to it). |
65 | |
124 | |
66 | All watchers are created by calling a method on the C<AnyEvent> class. |
125 | All watchers are created by calling a method on the C<AnyEvent> class. |
67 | |
126 | |
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127 | Many watchers either are used with "recursion" (repeating timers for |
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128 | example), or need to refer to their watcher object in other ways. |
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129 | |
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130 | An any way to achieve that is this pattern: |
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131 | |
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132 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
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133 | # you can use $w here, for example to undef it |
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134 | undef $w; |
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135 | }); |
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136 | |
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137 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
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138 | my variables are only visible after the statement in which they are |
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139 | declared. |
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140 | |
68 | =head2 IO WATCHERS |
141 | =head2 IO WATCHERS |
69 | |
142 | |
70 | You can create I/O watcher by calling the C<< AnyEvent->io >> method with |
143 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
71 | the following mandatory arguments: |
144 | with the following mandatory key-value pairs as arguments: |
72 | |
145 | |
73 | C<fh> the Perl I<filehandle> (not filedescriptor) to watch for |
146 | C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for |
74 | events. C<poll> must be a string that is either C<r> or C<w>, that creates |
147 | events. C<poll> must be a string that is either C<r> or C<w>, which |
75 | a watcher waiting for "r"eadable or "w"ritable events. C<cb> teh callback |
148 | creates a watcher waiting for "r"eadable or "w"ritable events, |
76 | to invoke everytime the filehandle becomes ready. |
149 | respectively. C<cb> is the callback to invoke each time the file handle |
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150 | becomes ready. |
77 | |
151 | |
78 | Only one io watcher per C<fh> and C<poll> combination is allowed (i.e. on |
152 | As long as the I/O watcher exists it will keep the file descriptor or a |
79 | a socket you can have one r + one w, not any more (limitation comes from |
153 | copy of it alive/open. |
80 | Tk - if you are sure you are not using Tk this limitation is gone). |
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81 | |
154 | |
82 | Filehandles will be kept alive, so as long as the watcher exists, the |
155 | It is not allowed to close a file handle as long as any watcher is active |
83 | filehandle exists, too. |
156 | on the underlying file descriptor. |
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157 | |
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158 | Some event loops issue spurious readyness notifications, so you should |
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159 | always use non-blocking calls when reading/writing from/to your file |
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160 | handles. |
84 | |
161 | |
85 | Example: |
162 | Example: |
86 | |
163 | |
87 | # wait for readability of STDIN, then read a line and disable the watcher |
164 | # wait for readability of STDIN, then read a line and disable the watcher |
88 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
165 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
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94 | =head2 TIME WATCHERS |
171 | =head2 TIME WATCHERS |
95 | |
172 | |
96 | You can create a time watcher by calling the C<< AnyEvent->timer >> |
173 | You can create a time watcher by calling the C<< AnyEvent->timer >> |
97 | method with the following mandatory arguments: |
174 | method with the following mandatory arguments: |
98 | |
175 | |
99 | C<after> after how many seconds (fractions are supported) should the timer |
176 | C<after> specifies after how many seconds (fractional values are |
100 | activate. C<cb> the callback to invoke. |
177 | supported) should the timer activate. C<cb> the callback to invoke in that |
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178 | case. |
101 | |
179 | |
102 | The timer callback will be invoked at most once: if you want a repeating |
180 | The timer callback will be invoked at most once: if you want a repeating |
103 | timer you have to create a new watcher (this is a limitation by both Tk |
181 | timer you have to create a new watcher (this is a limitation by both Tk |
104 | and Glib). |
182 | and Glib). |
105 | |
183 | |
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109 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
187 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
110 | warn "timeout\n"; |
188 | warn "timeout\n"; |
111 | }); |
189 | }); |
112 | |
190 | |
113 | # to cancel the timer: |
191 | # to cancel the timer: |
114 | undef $w |
192 | undef $w; |
115 | |
193 | |
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194 | Example 2: |
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195 | |
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196 | # fire an event after 0.5 seconds, then roughly every second |
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197 | my $w; |
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198 | |
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199 | my $cb = sub { |
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200 | # cancel the old timer while creating a new one |
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201 | $w = AnyEvent->timer (after => 1, cb => $cb); |
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202 | }; |
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203 | |
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204 | # start the "loop" by creating the first watcher |
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205 | $w = AnyEvent->timer (after => 0.5, cb => $cb); |
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206 | |
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207 | =head3 TIMING ISSUES |
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208 | |
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209 | There are two ways to handle timers: based on real time (relative, "fire |
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210 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
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211 | o'clock"). |
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212 | |
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213 | While most event loops expect timers to specified in a relative way, they |
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214 | use absolute time internally. This makes a difference when your clock |
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215 | "jumps", for example, when ntp decides to set your clock backwards from |
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216 | the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to |
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217 | fire "after" a second might actually take six years to finally fire. |
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218 | |
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219 | AnyEvent cannot compensate for this. The only event loop that is conscious |
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220 | about these issues is L<EV>, which offers both relative (ev_timer, based |
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221 | on true relative time) and absolute (ev_periodic, based on wallclock time) |
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222 | timers. |
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223 | |
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224 | AnyEvent always prefers relative timers, if available, matching the |
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225 | AnyEvent API. |
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226 | |
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227 | =head2 SIGNAL WATCHERS |
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228 | |
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229 | You can watch for signals using a signal watcher, C<signal> is the signal |
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230 | I<name> without any C<SIG> prefix, C<cb> is the Perl callback to |
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231 | be invoked whenever a signal occurs. |
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232 | |
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233 | Multiple signal occurances can be clumped together into one callback |
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234 | invocation, and callback invocation will be synchronous. synchronous means |
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235 | that it might take a while until the signal gets handled by the process, |
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236 | but it is guarenteed not to interrupt any other callbacks. |
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237 | |
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238 | The main advantage of using these watchers is that you can share a signal |
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239 | between multiple watchers. |
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240 | |
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241 | This watcher might use C<%SIG>, so programs overwriting those signals |
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242 | directly will likely not work correctly. |
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243 | |
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244 | Example: exit on SIGINT |
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245 | |
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246 | my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); |
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247 | |
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248 | =head2 CHILD PROCESS WATCHERS |
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249 | |
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250 | You can also watch on a child process exit and catch its exit status. |
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251 | |
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252 | The child process is specified by the C<pid> argument (if set to C<0>, it |
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253 | watches for any child process exit). The watcher will trigger as often |
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254 | as status change for the child are received. This works by installing a |
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255 | signal handler for C<SIGCHLD>. The callback will be called with the pid |
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256 | and exit status (as returned by waitpid). |
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257 | |
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258 | Example: wait for pid 1333 |
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259 | |
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260 | my $w = AnyEvent->child ( |
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261 | pid => 1333, |
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262 | cb => sub { |
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263 | my ($pid, $status) = @_; |
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264 | warn "pid $pid exited with status $status"; |
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265 | }, |
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266 | ); |
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267 | |
116 | =head2 CONDITION WATCHERS |
268 | =head2 CONDITION VARIABLES |
117 | |
269 | |
118 | Condition watchers can be created by calling the C<< AnyEvent->condvar >> |
270 | Condition variables can be created by calling the C<< AnyEvent->condvar >> |
119 | method without any arguments. |
271 | method without any arguments. |
120 | |
272 | |
121 | A condition watcher watches for a condition - precisely that the C<< |
273 | A condition variable waits for a condition - precisely that the C<< |
122 | ->broadcast >> method has been called. |
274 | ->broadcast >> method has been called. |
123 | |
275 | |
124 | The watcher has only two methods: |
276 | They are very useful to signal that a condition has been fulfilled, for |
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277 | example, if you write a module that does asynchronous http requests, |
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278 | then a condition variable would be the ideal candidate to signal the |
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279 | availability of results. |
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280 | |
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281 | You can also use condition variables to block your main program until |
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282 | an event occurs - for example, you could C<< ->wait >> in your main |
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283 | program until the user clicks the Quit button in your app, which would C<< |
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284 | ->broadcast >> the "quit" event. |
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285 | |
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286 | Note that condition variables recurse into the event loop - if you have |
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287 | two pirces of code that call C<< ->wait >> in a round-robbin fashion, you |
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288 | lose. Therefore, condition variables are good to export to your caller, but |
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289 | you should avoid making a blocking wait yourself, at least in callbacks, |
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290 | as this asks for trouble. |
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291 | |
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292 | This object has two methods: |
125 | |
293 | |
126 | =over 4 |
294 | =over 4 |
127 | |
295 | |
128 | =item $cv->wait |
296 | =item $cv->wait |
129 | |
297 | |
130 | Wait (blocking if necessary) until the C<< ->broadcast >> method has been |
298 | Wait (blocking if necessary) until the C<< ->broadcast >> method has been |
131 | called on c<$cv>, while servicing other watchers normally. |
299 | called on c<$cv>, while servicing other watchers normally. |
132 | |
300 | |
133 | Not all event models support a blocking wait - some die in that case, so |
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134 | if you are using this from a module, never require a blocking wait, but |
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135 | let the caller decide wether the call will block or not (for example, |
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136 | by coupling condition variables with some kind of request results and |
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137 | supporting callbacks so the caller knows that getting the result will not |
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138 | block, while still suppporting blockign waits if the caller so desires). |
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139 | |
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140 | You can only wait once on a condition - additional calls will return |
301 | You can only wait once on a condition - additional calls will return |
141 | immediately. |
302 | immediately. |
142 | |
303 | |
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304 | Not all event models support a blocking wait - some die in that case |
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305 | (programs might want to do that to stay interactive), so I<if you are |
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306 | using this from a module, never require a blocking wait>, but let the |
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307 | caller decide whether the call will block or not (for example, by coupling |
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308 | condition variables with some kind of request results and supporting |
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309 | callbacks so the caller knows that getting the result will not block, |
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310 | while still suppporting blocking waits if the caller so desires). |
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311 | |
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312 | Another reason I<never> to C<< ->wait >> in a module is that you cannot |
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313 | sensibly have two C<< ->wait >>'s in parallel, as that would require |
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314 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
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315 | can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and |
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316 | L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s |
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317 | from different coroutines, however). |
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318 | |
143 | =item $cv->broadcast |
319 | =item $cv->broadcast |
144 | |
320 | |
145 | Flag the condition as ready - a running C<< ->wait >> and all further |
321 | Flag the condition as ready - a running C<< ->wait >> and all further |
146 | calls to C<wait> will return after this method has been called. If nobody |
322 | calls to C<wait> will (eventually) return after this method has been |
147 | is waiting the broadcast will be remembered.. |
323 | called. If nobody is waiting the broadcast will be remembered.. |
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324 | |
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325 | =back |
148 | |
326 | |
149 | Example: |
327 | Example: |
150 | |
328 | |
151 | # wait till the result is ready |
329 | # wait till the result is ready |
152 | my $result_ready = AnyEvent->condvar; |
330 | my $result_ready = AnyEvent->condvar; |
153 | |
331 | |
154 | # do something such as adding a timer |
332 | # do something such as adding a timer |
155 | # or socket watcher the calls $result_ready->broadcast |
333 | # or socket watcher the calls $result_ready->broadcast |
156 | # when the "result" is ready. |
334 | # when the "result" is ready. |
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335 | # in this case, we simply use a timer: |
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336 | my $w = AnyEvent->timer ( |
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337 | after => 1, |
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338 | cb => sub { $result_ready->broadcast }, |
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339 | ); |
157 | |
340 | |
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341 | # this "blocks" (while handling events) till the watcher |
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342 | # calls broadcast |
158 | $result_ready->wait; |
343 | $result_ready->wait; |
159 | |
344 | |
160 | =back |
345 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
161 | |
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162 | =head2 SIGNAL WATCHERS |
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163 | |
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164 | You can listen for signals using a signal watcher, C<signal> is the signal |
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165 | I<name> without any C<SIG> prefix. Multiple signals events can be clumped |
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166 | together into one callback invocation, and callbakc invocation might or |
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167 | might not be asynchronous. |
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168 | |
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169 | These watchers might use C<%SIG>, so programs overwriting those signals |
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170 | directly will likely not work correctly. |
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171 | |
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172 | Example: exit on SIGINT |
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173 | |
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174 | my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); |
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175 | |
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176 | =head2 CHILD PROCESS WATCHERS |
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177 | |
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178 | You can also listen for the status of a child process specified by the |
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179 | C<pid> argument. The watcher will only trigger once. This works by |
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180 | installing a signal handler for C<SIGCHLD>. |
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181 | |
|
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182 | Example: wait for pid 1333 |
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183 | |
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184 | my $w = AnyEvent->child (pid => 1333, cb => sub { warn "exit status $?" }); |
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185 | |
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186 | =head1 GLOBALS |
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187 | |
346 | |
188 | =over 4 |
347 | =over 4 |
189 | |
348 | |
190 | =item $AnyEvent::MODEL |
349 | =item $AnyEvent::MODEL |
191 | |
350 | |
… | |
… | |
195 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
354 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
196 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
355 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
197 | |
356 | |
198 | The known classes so far are: |
357 | The known classes so far are: |
199 | |
358 | |
200 | AnyEvent::Impl::Coro based on Coro::Event, best choise. |
359 | AnyEvent::Impl::CoroEV based on Coro::EV, best choice. |
|
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360 | AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice. |
|
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361 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
201 | AnyEvent::Impl::Event based on Event, also best choice :) |
362 | AnyEvent::Impl::Event based on Event, second best choice. |
202 | AnyEvent::Impl::Glib based on Glib, second-best choice. |
363 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
203 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
364 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
204 | AnyEvent::Impl::Perl pure-perl implementation, inefficient. |
365 | AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable. |
|
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366 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
|
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367 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
|
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368 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
|
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369 | |
|
|
370 | There is no support for WxWidgets, as WxWidgets has no support for |
|
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371 | watching file handles. However, you can use WxWidgets through the |
|
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372 | POE Adaptor, as POE has a Wx backend that simply polls 20 times per |
|
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373 | second, which was considered to be too horrible to even consider for |
|
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374 | AnyEvent. Likewise, other POE backends can be used by AnyEvent by using |
|
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375 | it's adaptor. |
|
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376 | |
|
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377 | AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when |
|
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378 | autodetecting them. |
205 | |
379 | |
206 | =item AnyEvent::detect |
380 | =item AnyEvent::detect |
207 | |
381 | |
208 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model if |
382 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
209 | necessary. You should only call this function right before you would have |
383 | if necessary. You should only call this function right before you would |
210 | created an AnyEvent watcher anyway, that is, very late at runtime. |
384 | have created an AnyEvent watcher anyway, that is, as late as possible at |
|
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385 | runtime. |
211 | |
386 | |
212 | =back |
387 | =back |
213 | |
388 | |
214 | =head1 WHAT TO DO IN A MODULE |
389 | =head1 WHAT TO DO IN A MODULE |
215 | |
390 | |
216 | As a module author, you should "use AnyEvent" and call AnyEvent methods |
391 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
217 | freely, but you should not load a specific event module or rely on it. |
392 | freely, but you should not load a specific event module or rely on it. |
218 | |
393 | |
219 | Be careful when you create watchers in the module body - Anyevent will |
394 | Be careful when you create watchers in the module body - AnyEvent will |
220 | decide which event module to use as soon as the first method is called, so |
395 | decide which event module to use as soon as the first method is called, so |
221 | by calling AnyEvent in your module body you force the user of your module |
396 | by calling AnyEvent in your module body you force the user of your module |
222 | to load the event module first. |
397 | to load the event module first. |
223 | |
398 | |
|
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399 | Never call C<< ->wait >> on a condition variable unless you I<know> that |
|
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400 | the C<< ->broadcast >> method has been called on it already. This is |
|
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401 | because it will stall the whole program, and the whole point of using |
|
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402 | events is to stay interactive. |
|
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403 | |
|
|
404 | It is fine, however, to call C<< ->wait >> when the user of your module |
|
|
405 | requests it (i.e. if you create a http request object ad have a method |
|
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406 | called C<results> that returns the results, it should call C<< ->wait >> |
|
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407 | freely, as the user of your module knows what she is doing. always). |
|
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408 | |
224 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
409 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
225 | |
410 | |
226 | There will always be a single main program - the only place that should |
411 | There will always be a single main program - the only place that should |
227 | dictate which event model to use. |
412 | dictate which event model to use. |
228 | |
413 | |
229 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
414 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
230 | do anything special and let AnyEvent decide which implementation to chose. |
415 | do anything special (it does not need to be event-based) and let AnyEvent |
|
|
416 | decide which implementation to chose if some module relies on it. |
231 | |
417 | |
232 | If the main program relies on a specific event model (for example, in Gtk2 |
418 | If the main program relies on a specific event model. For example, in |
233 | programs you have to rely on either Glib or Glib::Event), you should load |
419 | Gtk2 programs you have to rely on the Glib module. You should load the |
234 | it before loading AnyEvent or any module that uses it, generally, as early |
420 | event module before loading AnyEvent or any module that uses it: generally |
235 | as possible. The reason is that modules might create watchers when they |
421 | speaking, you should load it as early as possible. The reason is that |
236 | are loaded, and AnyEvent will decide on the event model to use as soon as |
422 | modules might create watchers when they are loaded, and AnyEvent will |
237 | it creates watchers, and it might chose the wrong one unless you load the |
423 | decide on the event model to use as soon as it creates watchers, and it |
238 | correct one yourself. |
424 | might chose the wrong one unless you load the correct one yourself. |
239 | |
425 | |
240 | You can chose to use a rather inefficient pure-perl implementation by |
426 | You can chose to use a rather inefficient pure-perl implementation by |
241 | loading the C<AnyEvent::Impl::Perl> module, but letting AnyEvent chose is |
427 | loading the C<AnyEvent::Impl::Perl> module, which gives you similar |
242 | generally better. |
428 | behaviour everywhere, but letting AnyEvent chose is generally better. |
243 | |
429 | |
244 | =cut |
430 | =cut |
245 | |
431 | |
246 | package AnyEvent; |
432 | package AnyEvent; |
247 | |
433 | |
248 | no warnings; |
434 | no warnings; |
249 | use strict; |
435 | use strict; |
|
|
436 | |
250 | use Carp; |
437 | use Carp; |
251 | |
438 | |
252 | our $VERSION = '2.5'; |
439 | our $VERSION = '3.3'; |
253 | our $MODEL; |
440 | our $MODEL; |
254 | |
441 | |
255 | our $AUTOLOAD; |
442 | our $AUTOLOAD; |
256 | our @ISA; |
443 | our @ISA; |
257 | |
444 | |
258 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
445 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
259 | |
446 | |
260 | our @REGISTRY; |
447 | our @REGISTRY; |
261 | |
448 | |
262 | my @models = ( |
449 | my @models = ( |
|
|
450 | [Coro::EV:: => AnyEvent::Impl::CoroEV::], |
263 | [Coro::Event:: => AnyEvent::Impl::Coro::], |
451 | [Coro::Event:: => AnyEvent::Impl::CoroEvent::], |
|
|
452 | [EV:: => AnyEvent::Impl::EV::], |
264 | [Event:: => AnyEvent::Impl::Event::], |
453 | [Event:: => AnyEvent::Impl::Event::], |
265 | [Glib:: => AnyEvent::Impl::Glib::], |
454 | [Glib:: => AnyEvent::Impl::Glib::], |
266 | [Tk:: => AnyEvent::Impl::Tk::], |
455 | [Tk:: => AnyEvent::Impl::Tk::], |
|
|
456 | [Wx:: => AnyEvent::Impl::POE::], |
|
|
457 | [Prima:: => AnyEvent::Impl::POE::], |
267 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
458 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
|
|
459 | # everything below here will not be autoprobed as the pureperl backend should work everywhere |
|
|
460 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
|
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461 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
|
|
462 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
268 | ); |
463 | ); |
269 | |
464 | |
270 | our %method = map +($_ => 1), qw(io timer condvar broadcast wait signal one_event DESTROY); |
465 | our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY); |
271 | |
466 | |
272 | sub detect() { |
467 | sub detect() { |
273 | unless ($MODEL) { |
468 | unless ($MODEL) { |
274 | no strict 'refs'; |
469 | no strict 'refs'; |
275 | |
470 | |
|
|
471 | if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { |
|
|
472 | my $model = "AnyEvent::Impl::$1"; |
|
|
473 | if (eval "require $model") { |
|
|
474 | $MODEL = $model; |
|
|
475 | warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1; |
|
|
476 | } else { |
|
|
477 | warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose; |
|
|
478 | } |
|
|
479 | } |
|
|
480 | |
276 | # check for already loaded models |
481 | # check for already loaded models |
|
|
482 | unless ($MODEL) { |
277 | for (@REGISTRY, @models) { |
483 | for (@REGISTRY, @models) { |
278 | my ($package, $model) = @$_; |
484 | my ($package, $model) = @$_; |
279 | if (${"$package\::VERSION"} > 0) { |
485 | if (${"$package\::VERSION"} > 0) { |
280 | if (eval "require $model") { |
486 | if (eval "require $model") { |
281 | $MODEL = $model; |
487 | $MODEL = $model; |
282 | warn "AnyEvent: found model '$model', using it.\n" if $verbose > 1; |
488 | warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1; |
283 | last; |
489 | last; |
|
|
490 | } |
284 | } |
491 | } |
285 | } |
492 | } |
286 | } |
|
|
287 | |
493 | |
288 | unless ($MODEL) { |
494 | unless ($MODEL) { |
289 | # try to load a model |
495 | # try to load a model |
290 | |
496 | |
291 | for (@REGISTRY, @models) { |
497 | for (@REGISTRY, @models) { |
292 | my ($package, $model) = @$_; |
498 | my ($package, $model) = @$_; |
|
|
499 | if (eval "require $package" |
|
|
500 | and ${"$package\::VERSION"} > 0 |
293 | if (eval "require $model") { |
501 | and eval "require $model") { |
294 | $MODEL = $model; |
502 | $MODEL = $model; |
295 | warn "AnyEvent: autoprobed and loaded model '$model', using it.\n" if $verbose > 1; |
503 | warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1; |
296 | last; |
504 | last; |
|
|
505 | } |
297 | } |
506 | } |
|
|
507 | |
|
|
508 | $MODEL |
|
|
509 | 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."; |
298 | } |
510 | } |
299 | |
|
|
300 | $MODEL |
|
|
301 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: Event (or Coro+Event), Glib or Tk."; |
|
|
302 | } |
511 | } |
303 | |
512 | |
304 | unshift @ISA, $MODEL; |
513 | unshift @ISA, $MODEL; |
305 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
514 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
306 | } |
515 | } |
… | |
… | |
364 | |
573 | |
365 | # default implementation for ->child |
574 | # default implementation for ->child |
366 | |
575 | |
367 | our %PID_CB; |
576 | our %PID_CB; |
368 | our $CHLD_W; |
577 | our $CHLD_W; |
|
|
578 | our $CHLD_DELAY_W; |
369 | our $PID_IDLE; |
579 | our $PID_IDLE; |
370 | our $WNOHANG; |
580 | our $WNOHANG; |
371 | |
581 | |
372 | sub _child_wait { |
582 | sub _child_wait { |
373 | while (0 < (my $pid = waitpid -1, $WNOHANG)) { |
583 | while (0 < (my $pid = waitpid -1, $WNOHANG)) { |
374 | $_->() for values %{ (delete $PID_CB{$pid}) || {} }; |
584 | $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), |
|
|
585 | (values %{ $PID_CB{0} || {} }); |
375 | } |
586 | } |
376 | |
587 | |
377 | undef $PID_IDLE; |
588 | undef $PID_IDLE; |
|
|
589 | } |
|
|
590 | |
|
|
591 | sub _sigchld { |
|
|
592 | # make sure we deliver these changes "synchronous" with the event loop. |
|
|
593 | $CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub { |
|
|
594 | undef $CHLD_DELAY_W; |
|
|
595 | &_child_wait; |
|
|
596 | }); |
378 | } |
597 | } |
379 | |
598 | |
380 | sub child { |
599 | sub child { |
381 | my (undef, %arg) = @_; |
600 | my (undef, %arg) = @_; |
382 | |
601 | |
383 | my $pid = uc $arg{pid} |
602 | defined (my $pid = $arg{pid} + 0) |
384 | or Carp::croak "required option 'pid' is missing"; |
603 | or Carp::croak "required option 'pid' is missing"; |
385 | |
604 | |
386 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
605 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
387 | |
606 | |
388 | unless ($WNOHANG) { |
607 | unless ($WNOHANG) { |
389 | $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_child_wait); |
|
|
390 | $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1; |
608 | $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1; |
391 | } |
609 | } |
392 | |
610 | |
393 | # child could be a zombie already |
611 | unless ($CHLD_W) { |
394 | $PID_IDLE ||= AnyEvent->timer (after => 0, cb => \&_child_wait); |
612 | $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); |
|
|
613 | # child could be a zombie already, so make at least one round |
|
|
614 | &_sigchld; |
|
|
615 | } |
395 | |
616 | |
396 | bless [$pid, $arg{cb}], "AnyEvent::Base::Child" |
617 | bless [$pid, $arg{cb}], "AnyEvent::Base::Child" |
397 | } |
618 | } |
398 | |
619 | |
399 | sub AnyEvent::Base::Child::DESTROY { |
620 | sub AnyEvent::Base::Child::DESTROY { |
… | |
… | |
404 | |
625 | |
405 | undef $CHLD_W unless keys %PID_CB; |
626 | undef $CHLD_W unless keys %PID_CB; |
406 | } |
627 | } |
407 | |
628 | |
408 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
629 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
|
|
630 | |
|
|
631 | This is an advanced topic that you do not normally need to use AnyEvent in |
|
|
632 | a module. This section is only of use to event loop authors who want to |
|
|
633 | provide AnyEvent compatibility. |
409 | |
634 | |
410 | If you need to support another event library which isn't directly |
635 | If you need to support another event library which isn't directly |
411 | supported by AnyEvent, you can supply your own interface to it by |
636 | supported by AnyEvent, you can supply your own interface to it by |
412 | pushing, before the first watcher gets created, the package name of |
637 | pushing, before the first watcher gets created, the package name of |
413 | the event module and the package name of the interface to use onto |
638 | the event module and the package name of the interface to use onto |
414 | C<@AnyEvent::REGISTRY>. You can do that before and even without loading |
639 | C<@AnyEvent::REGISTRY>. You can do that before and even without loading |
415 | AnyEvent. |
640 | AnyEvent, so it is reasonably cheap. |
416 | |
641 | |
417 | Example: |
642 | Example: |
418 | |
643 | |
419 | push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::]; |
644 | push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::]; |
420 | |
645 | |
421 | This tells AnyEvent to (literally) use the C<urxvt::anyevent::> |
646 | This tells AnyEvent to (literally) use the C<urxvt::anyevent::> |
422 | package/class when it finds the C<urxvt> package/module is loaded. When |
647 | package/class when it finds the C<urxvt> package/module is already loaded. |
|
|
648 | |
423 | AnyEvent is loaded and asked to find a suitable event model, it will |
649 | When AnyEvent is loaded and asked to find a suitable event model, it |
424 | first check for the presence of urxvt. |
650 | will first check for the presence of urxvt by trying to C<use> the |
|
|
651 | C<urxvt::anyevent> module. |
425 | |
652 | |
426 | The class should provide implementations for all watcher types (see |
653 | The class should provide implementations for all watcher types. See |
427 | L<AnyEvent::Impl::Event> (source code), L<AnyEvent::Impl::Glib> |
654 | L<AnyEvent::Impl::EV> (source code), L<AnyEvent::Impl::Glib> (Source code) |
428 | (Source code) and so on for actual examples, use C<perldoc -m |
655 | and so on for actual examples. Use C<perldoc -m AnyEvent::Impl::Glib> to |
429 | AnyEvent::Impl::Glib> to see the sources). |
656 | see the sources. |
430 | |
657 | |
|
|
658 | If you don't provide C<signal> and C<child> watchers than AnyEvent will |
|
|
659 | provide suitable (hopefully) replacements. |
|
|
660 | |
431 | The above isn't fictitious, the I<rxvt-unicode> (a.k.a. urxvt) |
661 | The above example isn't fictitious, the I<rxvt-unicode> (a.k.a. urxvt) |
432 | uses the above line as-is. An interface isn't included in AnyEvent |
662 | terminal emulator uses the above line as-is. An interface isn't included |
433 | because it doesn't make sense outside the embedded interpreter inside |
663 | in AnyEvent because it doesn't make sense outside the embedded interpreter |
434 | I<rxvt-unicode>, and it is updated and maintained as part of the |
664 | inside I<rxvt-unicode>, and it is updated and maintained as part of the |
435 | I<rxvt-unicode> distribution. |
665 | I<rxvt-unicode> distribution. |
436 | |
666 | |
437 | I<rxvt-unicode> also cheats a bit by not providing blocking access to |
667 | I<rxvt-unicode> also cheats a bit by not providing blocking access to |
438 | condition variables: code blocking while waiting for a condition will |
668 | condition variables: code blocking while waiting for a condition will |
439 | C<die>. This still works with most modules/usages, and blocking calls must |
669 | C<die>. This still works with most modules/usages, and blocking calls must |
440 | not be in an interactive appliation, so it makes sense. |
670 | not be done in an interactive application, so it makes sense. |
441 | |
671 | |
442 | =head1 ENVIRONMENT VARIABLES |
672 | =head1 ENVIRONMENT VARIABLES |
443 | |
673 | |
444 | The following environment variables are used by this module: |
674 | The following environment variables are used by this module: |
445 | |
675 | |
446 | C<PERL_ANYEVENT_VERBOSE> when set to C<2> or higher, reports which event |
676 | =over 4 |
447 | model gets used. |
|
|
448 | |
677 | |
|
|
678 | =item C<PERL_ANYEVENT_VERBOSE> |
|
|
679 | |
|
|
680 | By default, AnyEvent will be completely silent except in fatal |
|
|
681 | conditions. You can set this environment variable to make AnyEvent more |
|
|
682 | talkative. |
|
|
683 | |
|
|
684 | When set to C<1> or higher, causes AnyEvent to warn about unexpected |
|
|
685 | conditions, such as not being able to load the event model specified by |
|
|
686 | C<PERL_ANYEVENT_MODEL>. |
|
|
687 | |
|
|
688 | When set to C<2> or higher, cause AnyEvent to report to STDERR which event |
|
|
689 | model it chooses. |
|
|
690 | |
|
|
691 | =item C<PERL_ANYEVENT_MODEL> |
|
|
692 | |
|
|
693 | This can be used to specify the event model to be used by AnyEvent, before |
|
|
694 | autodetection and -probing kicks in. It must be a string consisting |
|
|
695 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
|
|
696 | and the resulting module name is loaded and if the load was successful, |
|
|
697 | used as event model. If it fails to load AnyEvent will proceed with |
|
|
698 | autodetection and -probing. |
|
|
699 | |
|
|
700 | This functionality might change in future versions. |
|
|
701 | |
|
|
702 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
|
|
703 | could start your program like this: |
|
|
704 | |
|
|
705 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
706 | |
|
|
707 | =back |
|
|
708 | |
449 | =head1 EXAMPLE |
709 | =head1 EXAMPLE PROGRAM |
450 | |
710 | |
451 | The following program uses an io watcher to read data from stdin, a timer |
711 | The following program uses an IO watcher to read data from STDIN, a timer |
452 | to display a message once per second, and a condvar to exit the program |
712 | to display a message once per second, and a condition variable to quit the |
453 | when the user enters quit: |
713 | program when the user enters quit: |
454 | |
714 | |
455 | use AnyEvent; |
715 | use AnyEvent; |
456 | |
716 | |
457 | my $cv = AnyEvent->condvar; |
717 | my $cv = AnyEvent->condvar; |
458 | |
718 | |
459 | my $io_watcher = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
719 | my $io_watcher = AnyEvent->io ( |
|
|
720 | fh => \*STDIN, |
|
|
721 | poll => 'r', |
|
|
722 | cb => sub { |
460 | warn "io event <$_[0]>\n"; # will always output <r> |
723 | warn "io event <$_[0]>\n"; # will always output <r> |
461 | chomp (my $input = <STDIN>); # read a line |
724 | chomp (my $input = <STDIN>); # read a line |
462 | warn "read: $input\n"; # output what has been read |
725 | warn "read: $input\n"; # output what has been read |
463 | $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i |
726 | $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i |
|
|
727 | }, |
464 | }); |
728 | ); |
465 | |
729 | |
466 | my $time_watcher; # can only be used once |
730 | my $time_watcher; # can only be used once |
467 | |
731 | |
468 | sub new_timer { |
732 | sub new_timer { |
469 | $timer = AnyEvent->timer (after => 1, cb => sub { |
733 | $timer = AnyEvent->timer (after => 1, cb => sub { |
… | |
… | |
551 | $txn->{finished}->wait; |
815 | $txn->{finished}->wait; |
552 | return $txn->{result}; |
816 | return $txn->{result}; |
553 | |
817 | |
554 | The actual code goes further and collects all errors (C<die>s, exceptions) |
818 | The actual code goes further and collects all errors (C<die>s, exceptions) |
555 | that occured during request processing. The C<result> method detects |
819 | that occured during request processing. The C<result> method detects |
556 | wether an exception as thrown (it is stored inside the $txn object) |
820 | whether an exception as thrown (it is stored inside the $txn object) |
557 | and just throws the exception, which means connection errors and other |
821 | and just throws the exception, which means connection errors and other |
558 | problems get reported tot he code that tries to use the result, not in a |
822 | problems get reported tot he code that tries to use the result, not in a |
559 | random callback. |
823 | random callback. |
560 | |
824 | |
561 | All of this enables the following usage styles: |
825 | All of this enables the following usage styles: |
562 | |
826 | |
563 | 1. Blocking: |
827 | 1. Blocking: |
564 | |
828 | |
565 | my $data = $fcp->client_get ($url); |
829 | my $data = $fcp->client_get ($url); |
566 | |
830 | |
567 | 2. Blocking, but parallelizing: |
831 | 2. Blocking, but running in parallel: |
568 | |
832 | |
569 | my @datas = map $_->result, |
833 | my @datas = map $_->result, |
570 | map $fcp->txn_client_get ($_), |
834 | map $fcp->txn_client_get ($_), |
571 | @urls; |
835 | @urls; |
572 | |
836 | |
573 | Both blocking examples work without the module user having to know |
837 | Both blocking examples work without the module user having to know |
574 | anything about events. |
838 | anything about events. |
575 | |
839 | |
576 | 3a. Event-based in a main program, using any support Event module: |
840 | 3a. Event-based in a main program, using any supported event module: |
577 | |
841 | |
578 | use Event; |
842 | use EV; |
579 | |
843 | |
580 | $fcp->txn_client_get ($url)->cb (sub { |
844 | $fcp->txn_client_get ($url)->cb (sub { |
581 | my $txn = shift; |
845 | my $txn = shift; |
582 | my $data = $txn->result; |
846 | my $data = $txn->result; |
583 | ... |
847 | ... |
584 | }); |
848 | }); |
585 | |
849 | |
586 | Event::loop; |
850 | EV::loop; |
587 | |
851 | |
588 | 3b. The module user could use AnyEvent, too: |
852 | 3b. The module user could use AnyEvent, too: |
589 | |
853 | |
590 | use AnyEvent; |
854 | use AnyEvent; |
591 | |
855 | |
… | |
… | |
596 | $quit->broadcast; |
860 | $quit->broadcast; |
597 | }); |
861 | }); |
598 | |
862 | |
599 | $quit->wait; |
863 | $quit->wait; |
600 | |
864 | |
|
|
865 | |
|
|
866 | =head1 BENCHMARK |
|
|
867 | |
|
|
868 | To give you an idea of the performance and overheads that AnyEvent adds |
|
|
869 | over the backends directly, here is a benchmark of various supported event |
|
|
870 | models natively and with anyevent. The benchmark creates a lot of timers |
|
|
871 | (with a zero timeout) and io watchers (watching STDOUT, a pty, to become |
|
|
872 | writable, which it is), lets them fire exactly once and destroys them |
|
|
873 | again. |
|
|
874 | |
|
|
875 | Explanation of the fields: |
|
|
876 | |
|
|
877 | I<watcher> is the number of event watchers created/destroyed. Sicne |
|
|
878 | different event models have vastly different performance each backend was |
|
|
879 | handed a number of watchers so that overall runtime is acceptable and |
|
|
880 | similar to all backends (and keep them from crashing). |
|
|
881 | |
|
|
882 | I<bytes> is the number of bytes (as measured by resident set size) used by |
|
|
883 | each watcher. |
|
|
884 | |
|
|
885 | I<create> is the time, in microseconds, to create a single watcher. |
|
|
886 | |
|
|
887 | I<invoke> is the time, in microseconds, used to invoke a simple callback |
|
|
888 | that simply counts down. |
|
|
889 | |
|
|
890 | I<destroy> is the time, in microseconds, to destroy a single watcher. |
|
|
891 | |
|
|
892 | name watcher bytes create invoke destroy comment |
|
|
893 | EV/EV 400000 244 0.56 0.46 0.31 EV native interface |
|
|
894 | EV/Any 100000 610 3.52 0.91 0.75 |
|
|
895 | CoroEV/Any 100000 610 3.49 0.92 0.75 coroutines + Coro::Signal |
|
|
896 | Perl/Any 10000 654 4.64 1.22 0.77 pure perl implementation |
|
|
897 | Event/Event 10000 523 28.05 21.38 5.22 Event native interface |
|
|
898 | Event/Any 10000 943 34.43 20.48 1.39 |
|
|
899 | Glib/Any 16000 1357 96.99 12.55 55.51 quadratic behaviour |
|
|
900 | Tk/Any 2000 1855 27.01 66.61 14.03 SEGV with >> 2000 watchers |
|
|
901 | POE/Select 2000 6343 94.69 807.65 562.69 POE::Loop::Select |
|
|
902 | POE/Event 2000 6644 108.15 768.19 14.33 POE::Loop::Event |
|
|
903 | |
|
|
904 | Discussion: The benchmark does I<not> bench scalability of the |
|
|
905 | backend. For example a select-based backend (such as the pureperl one) can |
|
|
906 | never compete with a backend using epoll. In this benchmark, only a single |
|
|
907 | filehandle is used. |
|
|
908 | |
|
|
909 | EV is the sole leader regarding speed and memory use, which are both |
|
|
910 | maximal/minimal. Even when going through AnyEvent, there is only one event |
|
|
911 | loop that uses less memory (the Event module natively), and no faster |
|
|
912 | event model. |
|
|
913 | |
|
|
914 | The pure perl implementation is hit in a few sweet spots (both the |
|
|
915 | zero timeout and the use of a single fd hit optimisations in the perl |
|
|
916 | interpreter and the backend itself), but it shows that it adds very little |
|
|
917 | overhead in itself. Like any select-based backend it's performance becomes |
|
|
918 | really bad with lots of file descriptors. |
|
|
919 | |
|
|
920 | The Event module has a relatively high setup and callback invocation cost, |
|
|
921 | but overall scores on the third place. |
|
|
922 | |
|
|
923 | Glib has a little higher memory cost, a bit fster callback invocation and |
|
|
924 | has a similar speed as Event. |
|
|
925 | |
|
|
926 | The Tk backend works relatively well, the fact that it crashes with |
|
|
927 | more than 2000 watchers is a big setback, however, as correctness takes |
|
|
928 | precedence over speed. |
|
|
929 | |
|
|
930 | POE, regardless of backend (wether it's pure perl select backend or the |
|
|
931 | Event backend) shows abysmal performance and memory usage: Watchers use |
|
|
932 | almost 30 times as much memory as EV watchers, and 10 times as much memory |
|
|
933 | as both Event or EV via AnyEvent. |
|
|
934 | |
|
|
935 | Summary: using EV through AnyEvent is faster than any other event |
|
|
936 | loop. The overhead AnyEvent adds can be very small, and you should avoid |
|
|
937 | POE like the plague if you want performance or reasonable memory usage. |
|
|
938 | |
|
|
939 | |
|
|
940 | =head1 FORK |
|
|
941 | |
|
|
942 | Most event libraries are not fork-safe. The ones who are usually are |
|
|
943 | because they are so inefficient. Only L<EV> is fully fork-aware. |
|
|
944 | |
|
|
945 | If you have to fork, you must either do so I<before> creating your first |
|
|
946 | watcher OR you must not use AnyEvent at all in the child. |
|
|
947 | |
|
|
948 | |
|
|
949 | =head1 SECURITY CONSIDERATIONS |
|
|
950 | |
|
|
951 | AnyEvent can be forced to load any event model via |
|
|
952 | $ENV{PERL_ANYEVENT_MODEL}. While this cannot (to my knowledge) be used to |
|
|
953 | execute arbitrary code or directly gain access, it can easily be used to |
|
|
954 | make the program hang or malfunction in subtle ways, as AnyEvent watchers |
|
|
955 | will not be active when the program uses a different event model than |
|
|
956 | specified in the variable. |
|
|
957 | |
|
|
958 | You can make AnyEvent completely ignore this variable by deleting it |
|
|
959 | before the first watcher gets created, e.g. with a C<BEGIN> block: |
|
|
960 | |
|
|
961 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
|
|
962 | |
|
|
963 | use AnyEvent; |
|
|
964 | |
|
|
965 | |
601 | =head1 SEE ALSO |
966 | =head1 SEE ALSO |
602 | |
967 | |
603 | Event modules: L<Coro::Event>, L<Coro>, L<Event>, L<Glib::Event>, L<Glib>. |
968 | Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>, |
|
|
969 | L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>, |
|
|
970 | L<Event::Lib>, L<Qt>, L<POE>. |
604 | |
971 | |
|
|
972 | Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>, |
605 | Implementations: L<AnyEvent::Impl::Coro>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>. |
973 | L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, |
|
|
974 | L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>, |
|
|
975 | L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>. |
606 | |
976 | |
607 | Nontrivial usage example: L<Net::FCP>. |
977 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. |
608 | |
978 | |
609 | =head1 |
979 | |
|
|
980 | =head1 AUTHOR |
|
|
981 | |
|
|
982 | Marc Lehmann <schmorp@schmorp.de> |
|
|
983 | http://home.schmorp.de/ |
610 | |
984 | |
611 | =cut |
985 | =cut |
612 | |
986 | |
613 | 1 |
987 | 1 |
614 | |
988 | |