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 | |
11 | my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { |
11 | my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { ... }); |
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12 | |
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13 | my $w = AnyEvent->timer (after => $seconds, cb => sub { ... }); |
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14 | my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ... |
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15 | |
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16 | print AnyEvent->now; # prints current event loop time |
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17 | print AnyEvent->time; # think Time::HiRes::time or simply CORE::time. |
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18 | |
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19 | my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... }); |
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20 | |
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21 | my $w = AnyEvent->child (pid => $pid, cb => sub { |
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22 | my ($pid, $status) = @_; |
12 | ... |
23 | ... |
13 | }); |
24 | }); |
14 | |
25 | |
15 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
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16 | ... |
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17 | }); |
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18 | |
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19 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
26 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
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27 | $w->send; # wake up current and all future recv's |
20 | $w->wait; # enters "main loop" till $condvar gets ->broadcast |
28 | $w->recv; # enters "main loop" till $condvar gets ->send |
21 | $w->broadcast; # wake up current and all future wait's |
29 | # use a condvar in callback mode: |
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30 | $w->cb (sub { $_[0]->recv }); |
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31 | |
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32 | =head1 INTRODUCTION/TUTORIAL |
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33 | |
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34 | This manpage is mainly a reference manual. If you are interested |
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35 | in a tutorial or some gentle introduction, have a look at the |
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36 | L<AnyEvent::Intro> manpage. |
22 | |
37 | |
23 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
38 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
24 | |
39 | |
25 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
40 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
26 | nowadays. So what is different about AnyEvent? |
41 | nowadays. So what is different about AnyEvent? |
27 | |
42 | |
28 | Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of |
43 | Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of |
29 | policy> and AnyEvent is I<small and efficient>. |
44 | policy> and AnyEvent is I<small and efficient>. |
30 | |
45 | |
31 | First and foremost, I<AnyEvent is not an event model> itself, it only |
46 | First and foremost, I<AnyEvent is not an event model> itself, it only |
32 | interfaces to whatever event model the main program happens to use in a |
47 | interfaces to whatever event model the main program happens to use, in a |
33 | pragmatic way. For event models and certain classes of immortals alike, |
48 | pragmatic way. For event models and certain classes of immortals alike, |
34 | the statement "there can only be one" is a bitter reality: In general, |
49 | the statement "there can only be one" is a bitter reality: In general, |
35 | only one event loop can be active at the same time in a process. AnyEvent |
50 | only one event loop can be active at the same time in a process. AnyEvent |
36 | helps hiding the differences between those event loops. |
51 | cannot change this, but it can hide the differences between those event |
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52 | loops. |
37 | |
53 | |
38 | The goal of AnyEvent is to offer module authors the ability to do event |
54 | The goal of AnyEvent is to offer module authors the ability to do event |
39 | programming (waiting for I/O or timer events) without subscribing to a |
55 | programming (waiting for I/O or timer events) without subscribing to a |
40 | religion, a way of living, and most importantly: without forcing your |
56 | religion, a way of living, and most importantly: without forcing your |
41 | module users into the same thing by forcing them to use the same event |
57 | module users into the same thing by forcing them to use the same event |
42 | model you use. |
58 | model you use. |
43 | |
59 | |
44 | For modules like POE or IO::Async (which is a total misnomer as it is |
60 | For modules like POE or IO::Async (which is a total misnomer as it is |
45 | actually doing all I/O I<synchronously>...), using them in your module is |
61 | actually doing all I/O I<synchronously>...), using them in your module is |
46 | like joining a cult: After you joined, you are dependent on them and you |
62 | like joining a cult: After you joined, you are dependent on them and you |
47 | cannot use anything else, as it is simply incompatible to everything that |
63 | cannot use anything else, as they are simply incompatible to everything |
48 | isn't itself. What's worse, all the potential users of your module are |
64 | that isn't them. What's worse, all the potential users of your |
49 | I<also> forced to use the same event loop you use. |
65 | module are I<also> forced to use the same event loop you use. |
50 | |
66 | |
51 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
67 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
52 | fine. AnyEvent + Tk works fine etc. etc. but none of these work together |
68 | 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 |
69 | 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, |
70 | 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 |
71 | 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 |
72 | event models it supports (including stuff like IO::Async, as long as those |
57 | as those use one of the supported event loops. It is trivial to add new |
73 | use one of the supported event loops. It is trivial to add new event loops |
58 | event loops to AnyEvent, too, so it is future-proof). |
74 | to AnyEvent, too, so it is future-proof). |
59 | |
75 | |
60 | In addition to being free of having to use I<the one and only true event |
76 | 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 |
77 | 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 |
78 | 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 |
79 | 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 |
80 | offering the functionality that is necessary, in as thin as a wrapper as |
65 | technically possible. |
81 | technically possible. |
66 | |
82 | |
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83 | Of course, AnyEvent comes with a big (and fully optional!) toolbox |
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84 | of useful functionality, such as an asynchronous DNS resolver, 100% |
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85 | non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms |
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86 | such as Windows) and lots of real-world knowledge and workarounds for |
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87 | platform bugs and differences. |
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88 | |
67 | Of course, if you want lots of policy (this can arguably be somewhat |
89 | 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 |
90 | useful) and you want to force your users to use the one and only event |
69 | model, you should I<not> use this module. |
91 | model, you should I<not> use this module. |
70 | |
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71 | |
92 | |
72 | =head1 DESCRIPTION |
93 | =head1 DESCRIPTION |
73 | |
94 | |
74 | L<AnyEvent> provides an identical interface to multiple event loops. This |
95 | L<AnyEvent> provides an identical interface to multiple event loops. This |
75 | allows module authors to utilise an event loop without forcing module |
96 | allows module authors to utilise an event loop without forcing module |
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79 | The interface itself is vaguely similar, but not identical to the L<Event> |
100 | The interface itself is vaguely similar, but not identical to the L<Event> |
80 | module. |
101 | module. |
81 | |
102 | |
82 | During the first call of any watcher-creation method, the module tries |
103 | During the first call of any watcher-creation method, the module tries |
83 | to detect the currently loaded event loop by probing whether one of the |
104 | to detect the currently loaded event loop by probing whether one of the |
84 | following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>, |
105 | following modules is already loaded: L<EV>, |
85 | L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, |
106 | L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, |
86 | L<POE>. The first one found is used. If none are found, the module tries |
107 | L<POE>. The first one found is used. If none are found, the module tries |
87 | to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl |
108 | to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl |
88 | adaptor should always succeed) in the order given. The first one that can |
109 | adaptor should always succeed) in the order given. The first one that can |
89 | be successfully loaded will be used. If, after this, still none could be |
110 | be successfully loaded will be used. If, after this, still none could be |
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103 | starts using it, all bets are off. Maybe you should tell their authors to |
124 | starts using it, all bets are off. Maybe you should tell their authors to |
104 | use AnyEvent so their modules work together with others seamlessly... |
125 | use AnyEvent so their modules work together with others seamlessly... |
105 | |
126 | |
106 | The pure-perl implementation of AnyEvent is called |
127 | The pure-perl implementation of AnyEvent is called |
107 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
128 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
108 | explicitly. |
129 | explicitly and enjoy the high availability of that event loop :) |
109 | |
130 | |
110 | =head1 WATCHERS |
131 | =head1 WATCHERS |
111 | |
132 | |
112 | AnyEvent has the central concept of a I<watcher>, which is an object that |
133 | AnyEvent has the central concept of a I<watcher>, which is an object that |
113 | stores relevant data for each kind of event you are waiting for, such as |
134 | stores relevant data for each kind of event you are waiting for, such as |
114 | the callback to call, the filehandle to watch, etc. |
135 | the callback to call, the file handle to watch, etc. |
115 | |
136 | |
116 | These watchers are normal Perl objects with normal Perl lifetime. After |
137 | These watchers are normal Perl objects with normal Perl lifetime. After |
117 | creating a watcher it will immediately "watch" for events and invoke the |
138 | creating a watcher it will immediately "watch" for events and invoke the |
118 | callback when the event occurs (of course, only when the event model |
139 | callback when the event occurs (of course, only when the event model |
119 | is in control). |
140 | is in control). |
120 | |
141 | |
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142 | Note that B<callbacks must not permanently change global variables> |
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143 | potentially in use by the event loop (such as C<$_> or C<$[>) and that B<< |
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144 | callbacks must not C<die> >>. The former is good programming practise in |
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145 | Perl and the latter stems from the fact that exception handling differs |
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146 | widely between event loops. |
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147 | |
121 | To disable the watcher you have to destroy it (e.g. by setting the |
148 | To disable the watcher you have to destroy it (e.g. by setting the |
122 | variable you store it in to C<undef> or otherwise deleting all references |
149 | variable you store it in to C<undef> or otherwise deleting all references |
123 | to it). |
150 | to it). |
124 | |
151 | |
125 | All watchers are created by calling a method on the C<AnyEvent> class. |
152 | All watchers are created by calling a method on the C<AnyEvent> class. |
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127 | Many watchers either are used with "recursion" (repeating timers for |
154 | Many watchers either are used with "recursion" (repeating timers for |
128 | example), or need to refer to their watcher object in other ways. |
155 | example), or need to refer to their watcher object in other ways. |
129 | |
156 | |
130 | An any way to achieve that is this pattern: |
157 | An any way to achieve that is this pattern: |
131 | |
158 | |
132 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
159 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
133 | # you can use $w here, for example to undef it |
160 | # you can use $w here, for example to undef it |
134 | undef $w; |
161 | undef $w; |
135 | }); |
162 | }); |
136 | |
163 | |
137 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
164 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
138 | my variables are only visible after the statement in which they are |
165 | my variables are only visible after the statement in which they are |
139 | declared. |
166 | declared. |
140 | |
167 | |
141 | =head2 I/O WATCHERS |
168 | =head2 I/O WATCHERS |
142 | |
169 | |
143 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
170 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
144 | with the following mandatory key-value pairs as arguments: |
171 | with the following mandatory key-value pairs as arguments: |
145 | |
172 | |
146 | C<fh> the Perl I<file handle> (I<not> file descriptor) to watch |
173 | C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events |
147 | for events. C<poll> must be a string that is either C<r> or C<w>, |
174 | (AnyEvent might or might not keep a reference to this file handle). C<poll> |
148 | which creates a watcher waiting for "r"eadable or "w"ritable events, |
175 | must be a string that is either C<r> or C<w>, which creates a watcher |
149 | respectively. C<cb> is the callback to invoke each time the file handle |
176 | waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the |
150 | becomes ready. |
177 | callback to invoke each time the file handle becomes ready. |
151 | |
178 | |
152 | Although the callback might get passed parameters, their value and |
179 | Although the callback might get passed parameters, their value and |
153 | presence is undefined and you cannot rely on them. Portable AnyEvent |
180 | presence is undefined and you cannot rely on them. Portable AnyEvent |
154 | callbacks cannot use arguments passed to I/O watcher callbacks. |
181 | callbacks cannot use arguments passed to I/O watcher callbacks. |
155 | |
182 | |
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159 | |
186 | |
160 | Some event loops issue spurious readyness notifications, so you should |
187 | Some event loops issue spurious readyness notifications, so you should |
161 | always use non-blocking calls when reading/writing from/to your file |
188 | always use non-blocking calls when reading/writing from/to your file |
162 | handles. |
189 | handles. |
163 | |
190 | |
164 | Example: |
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165 | |
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166 | # wait for readability of STDIN, then read a line and disable the watcher |
191 | Example: wait for readability of STDIN, then read a line and disable the |
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192 | watcher. |
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193 | |
167 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
194 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
168 | chomp (my $input = <STDIN>); |
195 | chomp (my $input = <STDIN>); |
169 | warn "read: $input\n"; |
196 | warn "read: $input\n"; |
170 | undef $w; |
197 | undef $w; |
171 | }); |
198 | }); |
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181 | |
208 | |
182 | Although the callback might get passed parameters, their value and |
209 | Although the callback might get passed parameters, their value and |
183 | presence is undefined and you cannot rely on them. Portable AnyEvent |
210 | presence is undefined and you cannot rely on them. Portable AnyEvent |
184 | callbacks cannot use arguments passed to time watcher callbacks. |
211 | callbacks cannot use arguments passed to time watcher callbacks. |
185 | |
212 | |
186 | The timer callback will be invoked at most once: if you want a repeating |
213 | The callback will normally be invoked once only. If you specify another |
187 | timer you have to create a new watcher (this is a limitation by both Tk |
214 | parameter, C<interval>, as a strictly positive number (> 0), then the |
188 | and Glib). |
215 | callback will be invoked regularly at that interval (in fractional |
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216 | seconds) after the first invocation. If C<interval> is specified with a |
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217 | false value, then it is treated as if it were missing. |
189 | |
218 | |
190 | Example: |
219 | The callback will be rescheduled before invoking the callback, but no |
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220 | attempt is done to avoid timer drift in most backends, so the interval is |
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221 | only approximate. |
191 | |
222 | |
192 | # fire an event after 7.7 seconds |
223 | Example: fire an event after 7.7 seconds. |
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224 | |
193 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
225 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
194 | warn "timeout\n"; |
226 | warn "timeout\n"; |
195 | }); |
227 | }); |
196 | |
228 | |
197 | # to cancel the timer: |
229 | # to cancel the timer: |
198 | undef $w; |
230 | undef $w; |
199 | |
231 | |
200 | Example 2: |
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201 | |
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202 | # fire an event after 0.5 seconds, then roughly every second |
232 | Example 2: fire an event after 0.5 seconds, then roughly every second. |
203 | my $w; |
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204 | |
233 | |
205 | my $cb = sub { |
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206 | # cancel the old timer while creating a new one |
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207 | $w = AnyEvent->timer (after => 1, cb => $cb); |
234 | my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub { |
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235 | warn "timeout\n"; |
208 | }; |
236 | }; |
209 | |
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210 | # start the "loop" by creating the first watcher |
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211 | $w = AnyEvent->timer (after => 0.5, cb => $cb); |
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212 | |
237 | |
213 | =head3 TIMING ISSUES |
238 | =head3 TIMING ISSUES |
214 | |
239 | |
215 | There are two ways to handle timers: based on real time (relative, "fire |
240 | There are two ways to handle timers: based on real time (relative, "fire |
216 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
241 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
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228 | timers. |
253 | timers. |
229 | |
254 | |
230 | AnyEvent always prefers relative timers, if available, matching the |
255 | AnyEvent always prefers relative timers, if available, matching the |
231 | AnyEvent API. |
256 | AnyEvent API. |
232 | |
257 | |
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258 | AnyEvent has two additional methods that return the "current time": |
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259 | |
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260 | =over 4 |
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261 | |
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262 | =item AnyEvent->time |
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263 | |
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264 | This returns the "current wallclock time" as a fractional number of |
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265 | seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time> |
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266 | return, and the result is guaranteed to be compatible with those). |
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267 | |
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268 | It progresses independently of any event loop processing, i.e. each call |
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269 | will check the system clock, which usually gets updated frequently. |
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270 | |
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271 | =item AnyEvent->now |
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272 | |
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273 | This also returns the "current wallclock time", but unlike C<time>, above, |
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274 | this value might change only once per event loop iteration, depending on |
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275 | the event loop (most return the same time as C<time>, above). This is the |
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276 | time that AnyEvent's timers get scheduled against. |
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277 | |
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278 | I<In almost all cases (in all cases if you don't care), this is the |
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279 | function to call when you want to know the current time.> |
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280 | |
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281 | This function is also often faster then C<< AnyEvent->time >>, and |
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282 | thus the preferred method if you want some timestamp (for example, |
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283 | L<AnyEvent::Handle> uses this to update it's activity timeouts). |
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284 | |
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285 | The rest of this section is only of relevance if you try to be very exact |
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286 | with your timing, you can skip it without bad conscience. |
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287 | |
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288 | For a practical example of when these times differ, consider L<Event::Lib> |
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289 | and L<EV> and the following set-up: |
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290 | |
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291 | The event loop is running and has just invoked one of your callback at |
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292 | time=500 (assume no other callbacks delay processing). In your callback, |
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293 | you wait a second by executing C<sleep 1> (blocking the process for a |
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294 | second) and then (at time=501) you create a relative timer that fires |
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295 | after three seconds. |
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296 | |
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297 | With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will |
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298 | both return C<501>, because that is the current time, and the timer will |
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299 | be scheduled to fire at time=504 (C<501> + C<3>). |
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300 | |
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301 | With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current |
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302 | time), but C<< AnyEvent->now >> returns C<500>, as that is the time the |
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303 | last event processing phase started. With L<EV>, your timer gets scheduled |
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304 | to run at time=503 (C<500> + C<3>). |
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305 | |
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306 | In one sense, L<Event::Lib> is more exact, as it uses the current time |
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307 | regardless of any delays introduced by event processing. However, most |
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308 | callbacks do not expect large delays in processing, so this causes a |
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309 | higher drift (and a lot more system calls to get the current time). |
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310 | |
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311 | In another sense, L<EV> is more exact, as your timer will be scheduled at |
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312 | the same time, regardless of how long event processing actually took. |
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313 | |
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314 | In either case, if you care (and in most cases, you don't), then you |
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315 | can get whatever behaviour you want with any event loop, by taking the |
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316 | difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into |
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317 | account. |
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318 | |
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319 | =back |
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320 | |
233 | =head2 SIGNAL WATCHERS |
321 | =head2 SIGNAL WATCHERS |
234 | |
322 | |
235 | You can watch for signals using a signal watcher, C<signal> is the signal |
323 | You can watch for signals using a signal watcher, C<signal> is the signal |
236 | I<name> without any C<SIG> prefix, C<cb> is the Perl callback to |
324 | I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl |
237 | be invoked whenever a signal occurs. |
325 | callback to be invoked whenever a signal occurs. |
238 | |
326 | |
239 | Although the callback might get passed parameters, their value and |
327 | Although the callback might get passed parameters, their value and |
240 | presence is undefined and you cannot rely on them. Portable AnyEvent |
328 | presence is undefined and you cannot rely on them. Portable AnyEvent |
241 | callbacks cannot use arguments passed to signal watcher callbacks. |
329 | callbacks cannot use arguments passed to signal watcher callbacks. |
242 | |
330 | |
243 | Multiple signal occurances can be clumped together into one callback |
331 | Multiple signal occurrences can be clumped together into one callback |
244 | invocation, and callback invocation will be synchronous. synchronous means |
332 | invocation, and callback invocation will be synchronous. Synchronous means |
245 | that it might take a while until the signal gets handled by the process, |
333 | that it might take a while until the signal gets handled by the process, |
246 | but it is guarenteed not to interrupt any other callbacks. |
334 | but it is guaranteed not to interrupt any other callbacks. |
247 | |
335 | |
248 | The main advantage of using these watchers is that you can share a signal |
336 | The main advantage of using these watchers is that you can share a signal |
249 | between multiple watchers. |
337 | between multiple watchers. |
250 | |
338 | |
251 | This watcher might use C<%SIG>, so programs overwriting those signals |
339 | This watcher might use C<%SIG>, so programs overwriting those signals |
… | |
… | |
258 | =head2 CHILD PROCESS WATCHERS |
346 | =head2 CHILD PROCESS WATCHERS |
259 | |
347 | |
260 | You can also watch on a child process exit and catch its exit status. |
348 | You can also watch on a child process exit and catch its exit status. |
261 | |
349 | |
262 | The child process is specified by the C<pid> argument (if set to C<0>, it |
350 | The child process is specified by the C<pid> argument (if set to C<0>, it |
263 | watches for any child process exit). The watcher will trigger as often |
351 | watches for any child process exit). The watcher will triggered only when |
264 | as status change for the child are received. This works by installing a |
352 | the child process has finished and an exit status is available, not on |
265 | signal handler for C<SIGCHLD>. The callback will be called with the pid |
353 | any trace events (stopped/continued). |
266 | and exit status (as returned by waitpid), so unlike other watcher types, |
354 | |
267 | you I<can> rely on child watcher callback arguments. |
355 | The callback will be called with the pid and exit status (as returned by |
|
|
356 | waitpid), so unlike other watcher types, you I<can> rely on child watcher |
|
|
357 | callback arguments. |
|
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358 | |
|
|
359 | This watcher type works by installing a signal handler for C<SIGCHLD>, |
|
|
360 | and since it cannot be shared, nothing else should use SIGCHLD or reap |
|
|
361 | random child processes (waiting for specific child processes, e.g. inside |
|
|
362 | C<system>, is just fine). |
268 | |
363 | |
269 | There is a slight catch to child watchers, however: you usually start them |
364 | There is a slight catch to child watchers, however: you usually start them |
270 | I<after> the child process was created, and this means the process could |
365 | I<after> the child process was created, and this means the process could |
271 | have exited already (and no SIGCHLD will be sent anymore). |
366 | have exited already (and no SIGCHLD will be sent anymore). |
272 | |
367 | |
… | |
… | |
278 | AnyEvent program, you I<have> to create at least one watcher before you |
373 | AnyEvent program, you I<have> to create at least one watcher before you |
279 | C<fork> the child (alternatively, you can call C<AnyEvent::detect>). |
374 | C<fork> the child (alternatively, you can call C<AnyEvent::detect>). |
280 | |
375 | |
281 | Example: fork a process and wait for it |
376 | Example: fork a process and wait for it |
282 | |
377 | |
283 | my $done = AnyEvent->condvar; |
378 | my $done = AnyEvent->condvar; |
284 | |
379 | |
285 | AnyEvent::detect; # force event module to be initialised |
|
|
286 | |
|
|
287 | my $pid = fork or exit 5; |
380 | my $pid = fork or exit 5; |
288 | |
381 | |
289 | my $w = AnyEvent->child ( |
382 | my $w = AnyEvent->child ( |
290 | pid => $pid, |
383 | pid => $pid, |
291 | cb => sub { |
384 | cb => sub { |
292 | my ($pid, $status) = @_; |
385 | my ($pid, $status) = @_; |
293 | warn "pid $pid exited with status $status"; |
386 | warn "pid $pid exited with status $status"; |
294 | $done->broadcast; |
387 | $done->send; |
295 | }, |
388 | }, |
296 | ); |
389 | ); |
297 | |
390 | |
298 | # do something else, then wait for process exit |
391 | # do something else, then wait for process exit |
299 | $done->wait; |
392 | $done->recv; |
300 | |
393 | |
301 | =head2 CONDITION VARIABLES |
394 | =head2 CONDITION VARIABLES |
302 | |
395 | |
|
|
396 | If you are familiar with some event loops you will know that all of them |
|
|
397 | require you to run some blocking "loop", "run" or similar function that |
|
|
398 | will actively watch for new events and call your callbacks. |
|
|
399 | |
|
|
400 | AnyEvent is different, it expects somebody else to run the event loop and |
|
|
401 | will only block when necessary (usually when told by the user). |
|
|
402 | |
|
|
403 | The instrument to do that is called a "condition variable", so called |
|
|
404 | because they represent a condition that must become true. |
|
|
405 | |
303 | Condition variables can be created by calling the C<< AnyEvent->condvar >> |
406 | Condition variables can be created by calling the C<< AnyEvent->condvar |
304 | method without any arguments. |
407 | >> method, usually without arguments. The only argument pair allowed is |
305 | |
408 | |
306 | A condition variable waits for a condition - precisely that the C<< |
409 | C<cb>, which specifies a callback to be called when the condition variable |
307 | ->broadcast >> method has been called. |
410 | becomes true, with the condition variable as the first argument (but not |
|
|
411 | the results). |
308 | |
412 | |
309 | They are very useful to signal that a condition has been fulfilled, for |
413 | After creation, the condition variable is "false" until it becomes "true" |
|
|
414 | by calling the C<send> method (or calling the condition variable as if it |
|
|
415 | were a callback, read about the caveats in the description for the C<< |
|
|
416 | ->send >> method). |
|
|
417 | |
|
|
418 | Condition variables are similar to callbacks, except that you can |
|
|
419 | optionally wait for them. They can also be called merge points - points |
|
|
420 | in time where multiple outstanding events have been processed. And yet |
|
|
421 | another way to call them is transactions - each condition variable can be |
|
|
422 | used to represent a transaction, which finishes at some point and delivers |
|
|
423 | a result. |
|
|
424 | |
|
|
425 | Condition variables are very useful to signal that something has finished, |
310 | example, if you write a module that does asynchronous http requests, |
426 | for example, if you write a module that does asynchronous http requests, |
311 | then a condition variable would be the ideal candidate to signal the |
427 | then a condition variable would be the ideal candidate to signal the |
312 | availability of results. |
428 | availability of results. The user can either act when the callback is |
|
|
429 | called or can synchronously C<< ->recv >> for the results. |
313 | |
430 | |
314 | You can also use condition variables to block your main program until |
431 | You can also use them to simulate traditional event loops - for example, |
315 | an event occurs - for example, you could C<< ->wait >> in your main |
432 | you can block your main program until an event occurs - for example, you |
316 | program until the user clicks the Quit button in your app, which would C<< |
433 | could C<< ->recv >> in your main program until the user clicks the Quit |
317 | ->broadcast >> the "quit" event. |
434 | button of your app, which would C<< ->send >> the "quit" event. |
318 | |
435 | |
319 | Note that condition variables recurse into the event loop - if you have |
436 | Note that condition variables recurse into the event loop - if you have |
320 | two pirces of code that call C<< ->wait >> in a round-robbin fashion, you |
437 | two pieces of code that call C<< ->recv >> in a round-robin fashion, you |
321 | lose. Therefore, condition variables are good to export to your caller, but |
438 | lose. Therefore, condition variables are good to export to your caller, but |
322 | you should avoid making a blocking wait yourself, at least in callbacks, |
439 | you should avoid making a blocking wait yourself, at least in callbacks, |
323 | as this asks for trouble. |
440 | as this asks for trouble. |
324 | |
441 | |
325 | This object has two methods: |
442 | Condition variables are represented by hash refs in perl, and the keys |
|
|
443 | used by AnyEvent itself are all named C<_ae_XXX> to make subclassing |
|
|
444 | easy (it is often useful to build your own transaction class on top of |
|
|
445 | AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call |
|
|
446 | it's C<new> method in your own C<new> method. |
|
|
447 | |
|
|
448 | There are two "sides" to a condition variable - the "producer side" which |
|
|
449 | eventually calls C<< -> send >>, and the "consumer side", which waits |
|
|
450 | for the send to occur. |
|
|
451 | |
|
|
452 | Example: wait for a timer. |
|
|
453 | |
|
|
454 | # wait till the result is ready |
|
|
455 | my $result_ready = AnyEvent->condvar; |
|
|
456 | |
|
|
457 | # do something such as adding a timer |
|
|
458 | # or socket watcher the calls $result_ready->send |
|
|
459 | # when the "result" is ready. |
|
|
460 | # in this case, we simply use a timer: |
|
|
461 | my $w = AnyEvent->timer ( |
|
|
462 | after => 1, |
|
|
463 | cb => sub { $result_ready->send }, |
|
|
464 | ); |
|
|
465 | |
|
|
466 | # this "blocks" (while handling events) till the callback |
|
|
467 | # calls send |
|
|
468 | $result_ready->recv; |
|
|
469 | |
|
|
470 | Example: wait for a timer, but take advantage of the fact that |
|
|
471 | condition variables are also code references. |
|
|
472 | |
|
|
473 | my $done = AnyEvent->condvar; |
|
|
474 | my $delay = AnyEvent->timer (after => 5, cb => $done); |
|
|
475 | $done->recv; |
|
|
476 | |
|
|
477 | Example: Imagine an API that returns a condvar and doesn't support |
|
|
478 | callbacks. This is how you make a synchronous call, for example from |
|
|
479 | the main program: |
|
|
480 | |
|
|
481 | use AnyEvent::CouchDB; |
|
|
482 | |
|
|
483 | ... |
|
|
484 | |
|
|
485 | my @info = $couchdb->info->recv; |
|
|
486 | |
|
|
487 | And this is how you would just ste a callback to be called whenever the |
|
|
488 | results are available: |
|
|
489 | |
|
|
490 | $couchdb->info->cb (sub { |
|
|
491 | my @info = $_[0]->recv; |
|
|
492 | }); |
|
|
493 | |
|
|
494 | =head3 METHODS FOR PRODUCERS |
|
|
495 | |
|
|
496 | These methods should only be used by the producing side, i.e. the |
|
|
497 | code/module that eventually sends the signal. Note that it is also |
|
|
498 | the producer side which creates the condvar in most cases, but it isn't |
|
|
499 | uncommon for the consumer to create it as well. |
326 | |
500 | |
327 | =over 4 |
501 | =over 4 |
328 | |
502 | |
|
|
503 | =item $cv->send (...) |
|
|
504 | |
|
|
505 | Flag the condition as ready - a running C<< ->recv >> and all further |
|
|
506 | calls to C<recv> will (eventually) return after this method has been |
|
|
507 | called. If nobody is waiting the send will be remembered. |
|
|
508 | |
|
|
509 | If a callback has been set on the condition variable, it is called |
|
|
510 | immediately from within send. |
|
|
511 | |
|
|
512 | Any arguments passed to the C<send> call will be returned by all |
|
|
513 | future C<< ->recv >> calls. |
|
|
514 | |
|
|
515 | Condition variables are overloaded so one can call them directly |
|
|
516 | (as a code reference). Calling them directly is the same as calling |
|
|
517 | C<send>. Note, however, that many C-based event loops do not handle |
|
|
518 | overloading, so as tempting as it may be, passing a condition variable |
|
|
519 | instead of a callback does not work. Both the pure perl and EV loops |
|
|
520 | support overloading, however, as well as all functions that use perl to |
|
|
521 | invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for |
|
|
522 | example). |
|
|
523 | |
|
|
524 | =item $cv->croak ($error) |
|
|
525 | |
|
|
526 | Similar to send, but causes all call's to C<< ->recv >> to invoke |
|
|
527 | C<Carp::croak> with the given error message/object/scalar. |
|
|
528 | |
|
|
529 | This can be used to signal any errors to the condition variable |
|
|
530 | user/consumer. |
|
|
531 | |
|
|
532 | =item $cv->begin ([group callback]) |
|
|
533 | |
329 | =item $cv->wait |
534 | =item $cv->end |
330 | |
535 | |
331 | Wait (blocking if necessary) until the C<< ->broadcast >> method has been |
536 | These two methods are EXPERIMENTAL and MIGHT CHANGE. |
|
|
537 | |
|
|
538 | These two methods can be used to combine many transactions/events into |
|
|
539 | one. For example, a function that pings many hosts in parallel might want |
|
|
540 | to use a condition variable for the whole process. |
|
|
541 | |
|
|
542 | Every call to C<< ->begin >> will increment a counter, and every call to |
|
|
543 | C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end |
|
|
544 | >>, the (last) callback passed to C<begin> will be executed. That callback |
|
|
545 | is I<supposed> to call C<< ->send >>, but that is not required. If no |
|
|
546 | callback was set, C<send> will be called without any arguments. |
|
|
547 | |
|
|
548 | Let's clarify this with the ping example: |
|
|
549 | |
|
|
550 | my $cv = AnyEvent->condvar; |
|
|
551 | |
|
|
552 | my %result; |
|
|
553 | $cv->begin (sub { $cv->send (\%result) }); |
|
|
554 | |
|
|
555 | for my $host (@list_of_hosts) { |
|
|
556 | $cv->begin; |
|
|
557 | ping_host_then_call_callback $host, sub { |
|
|
558 | $result{$host} = ...; |
|
|
559 | $cv->end; |
|
|
560 | }; |
|
|
561 | } |
|
|
562 | |
|
|
563 | $cv->end; |
|
|
564 | |
|
|
565 | This code fragment supposedly pings a number of hosts and calls |
|
|
566 | C<send> after results for all then have have been gathered - in any |
|
|
567 | order. To achieve this, the code issues a call to C<begin> when it starts |
|
|
568 | each ping request and calls C<end> when it has received some result for |
|
|
569 | it. Since C<begin> and C<end> only maintain a counter, the order in which |
|
|
570 | results arrive is not relevant. |
|
|
571 | |
|
|
572 | There is an additional bracketing call to C<begin> and C<end> outside the |
|
|
573 | loop, which serves two important purposes: first, it sets the callback |
|
|
574 | to be called once the counter reaches C<0>, and second, it ensures that |
|
|
575 | C<send> is called even when C<no> hosts are being pinged (the loop |
|
|
576 | doesn't execute once). |
|
|
577 | |
|
|
578 | This is the general pattern when you "fan out" into multiple subrequests: |
|
|
579 | use an outer C<begin>/C<end> pair to set the callback and ensure C<end> |
|
|
580 | is called at least once, and then, for each subrequest you start, call |
|
|
581 | C<begin> and for each subrequest you finish, call C<end>. |
|
|
582 | |
|
|
583 | =back |
|
|
584 | |
|
|
585 | =head3 METHODS FOR CONSUMERS |
|
|
586 | |
|
|
587 | These methods should only be used by the consuming side, i.e. the |
|
|
588 | code awaits the condition. |
|
|
589 | |
|
|
590 | =over 4 |
|
|
591 | |
|
|
592 | =item $cv->recv |
|
|
593 | |
|
|
594 | Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak |
332 | called on c<$cv>, while servicing other watchers normally. |
595 | >> methods have been called on c<$cv>, while servicing other watchers |
|
|
596 | normally. |
333 | |
597 | |
334 | You can only wait once on a condition - additional calls will return |
598 | You can only wait once on a condition - additional calls are valid but |
335 | immediately. |
599 | will return immediately. |
|
|
600 | |
|
|
601 | If an error condition has been set by calling C<< ->croak >>, then this |
|
|
602 | function will call C<croak>. |
|
|
603 | |
|
|
604 | In list context, all parameters passed to C<send> will be returned, |
|
|
605 | in scalar context only the first one will be returned. |
336 | |
606 | |
337 | Not all event models support a blocking wait - some die in that case |
607 | Not all event models support a blocking wait - some die in that case |
338 | (programs might want to do that to stay interactive), so I<if you are |
608 | (programs might want to do that to stay interactive), so I<if you are |
339 | using this from a module, never require a blocking wait>, but let the |
609 | using this from a module, never require a blocking wait>, but let the |
340 | caller decide whether the call will block or not (for example, by coupling |
610 | caller decide whether the call will block or not (for example, by coupling |
341 | condition variables with some kind of request results and supporting |
611 | condition variables with some kind of request results and supporting |
342 | callbacks so the caller knows that getting the result will not block, |
612 | callbacks so the caller knows that getting the result will not block, |
343 | while still suppporting blocking waits if the caller so desires). |
613 | while still supporting blocking waits if the caller so desires). |
344 | |
614 | |
345 | Another reason I<never> to C<< ->wait >> in a module is that you cannot |
615 | Another reason I<never> to C<< ->recv >> in a module is that you cannot |
346 | sensibly have two C<< ->wait >>'s in parallel, as that would require |
616 | sensibly have two C<< ->recv >>'s in parallel, as that would require |
347 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
617 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
348 | can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and |
618 | can supply. |
349 | L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s |
|
|
350 | from different coroutines, however). |
|
|
351 | |
619 | |
352 | =item $cv->broadcast |
620 | The L<Coro> module, however, I<can> and I<does> supply coroutines and, in |
|
|
621 | fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe |
|
|
622 | versions and also integrates coroutines into AnyEvent, making blocking |
|
|
623 | C<< ->recv >> calls perfectly safe as long as they are done from another |
|
|
624 | coroutine (one that doesn't run the event loop). |
353 | |
625 | |
354 | Flag the condition as ready - a running C<< ->wait >> and all further |
626 | You can ensure that C<< -recv >> never blocks by setting a callback and |
355 | calls to C<wait> will (eventually) return after this method has been |
627 | only calling C<< ->recv >> from within that callback (or at a later |
356 | called. If nobody is waiting the broadcast will be remembered.. |
628 | time). This will work even when the event loop does not support blocking |
|
|
629 | waits otherwise. |
|
|
630 | |
|
|
631 | =item $bool = $cv->ready |
|
|
632 | |
|
|
633 | Returns true when the condition is "true", i.e. whether C<send> or |
|
|
634 | C<croak> have been called. |
|
|
635 | |
|
|
636 | =item $cb = $cv->cb ($cb->($cv)) |
|
|
637 | |
|
|
638 | This is a mutator function that returns the callback set and optionally |
|
|
639 | replaces it before doing so. |
|
|
640 | |
|
|
641 | The callback will be called when the condition becomes "true", i.e. when |
|
|
642 | C<send> or C<croak> are called, with the only argument being the condition |
|
|
643 | variable itself. Calling C<recv> inside the callback or at any later time |
|
|
644 | is guaranteed not to block. |
357 | |
645 | |
358 | =back |
646 | =back |
359 | |
|
|
360 | Example: |
|
|
361 | |
|
|
362 | # wait till the result is ready |
|
|
363 | my $result_ready = AnyEvent->condvar; |
|
|
364 | |
|
|
365 | # do something such as adding a timer |
|
|
366 | # or socket watcher the calls $result_ready->broadcast |
|
|
367 | # when the "result" is ready. |
|
|
368 | # in this case, we simply use a timer: |
|
|
369 | my $w = AnyEvent->timer ( |
|
|
370 | after => 1, |
|
|
371 | cb => sub { $result_ready->broadcast }, |
|
|
372 | ); |
|
|
373 | |
|
|
374 | # this "blocks" (while handling events) till the watcher |
|
|
375 | # calls broadcast |
|
|
376 | $result_ready->wait; |
|
|
377 | |
647 | |
378 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
648 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
379 | |
649 | |
380 | =over 4 |
650 | =over 4 |
381 | |
651 | |
… | |
… | |
387 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
657 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
388 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
658 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
389 | |
659 | |
390 | The known classes so far are: |
660 | The known classes so far are: |
391 | |
661 | |
392 | AnyEvent::Impl::CoroEV based on Coro::EV, best choice. |
|
|
393 | AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice. |
|
|
394 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
662 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
395 | AnyEvent::Impl::Event based on Event, second best choice. |
663 | AnyEvent::Impl::Event based on Event, second best choice. |
|
|
664 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
396 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
665 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
397 | AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable. |
|
|
398 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
666 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
399 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
667 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
400 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
668 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
401 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
669 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
402 | |
670 | |
… | |
… | |
415 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
683 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
416 | if necessary. You should only call this function right before you would |
684 | if necessary. You should only call this function right before you would |
417 | have created an AnyEvent watcher anyway, that is, as late as possible at |
685 | have created an AnyEvent watcher anyway, that is, as late as possible at |
418 | runtime. |
686 | runtime. |
419 | |
687 | |
|
|
688 | =item $guard = AnyEvent::post_detect { BLOCK } |
|
|
689 | |
|
|
690 | Arranges for the code block to be executed as soon as the event model is |
|
|
691 | autodetected (or immediately if this has already happened). |
|
|
692 | |
|
|
693 | If called in scalar or list context, then it creates and returns an object |
|
|
694 | that automatically removes the callback again when it is destroyed. See |
|
|
695 | L<Coro::BDB> for a case where this is useful. |
|
|
696 | |
|
|
697 | =item @AnyEvent::post_detect |
|
|
698 | |
|
|
699 | If there are any code references in this array (you can C<push> to it |
|
|
700 | before or after loading AnyEvent), then they will called directly after |
|
|
701 | the event loop has been chosen. |
|
|
702 | |
|
|
703 | You should check C<$AnyEvent::MODEL> before adding to this array, though: |
|
|
704 | if it contains a true value then the event loop has already been detected, |
|
|
705 | and the array will be ignored. |
|
|
706 | |
|
|
707 | Best use C<AnyEvent::post_detect { BLOCK }> instead. |
|
|
708 | |
420 | =back |
709 | =back |
421 | |
710 | |
422 | =head1 WHAT TO DO IN A MODULE |
711 | =head1 WHAT TO DO IN A MODULE |
423 | |
712 | |
424 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
713 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
… | |
… | |
427 | Be careful when you create watchers in the module body - AnyEvent will |
716 | Be careful when you create watchers in the module body - AnyEvent will |
428 | decide which event module to use as soon as the first method is called, so |
717 | decide which event module to use as soon as the first method is called, so |
429 | by calling AnyEvent in your module body you force the user of your module |
718 | by calling AnyEvent in your module body you force the user of your module |
430 | to load the event module first. |
719 | to load the event module first. |
431 | |
720 | |
432 | Never call C<< ->wait >> on a condition variable unless you I<know> that |
721 | Never call C<< ->recv >> on a condition variable unless you I<know> that |
433 | the C<< ->broadcast >> method has been called on it already. This is |
722 | the C<< ->send >> method has been called on it already. This is |
434 | because it will stall the whole program, and the whole point of using |
723 | because it will stall the whole program, and the whole point of using |
435 | events is to stay interactive. |
724 | events is to stay interactive. |
436 | |
725 | |
437 | It is fine, however, to call C<< ->wait >> when the user of your module |
726 | It is fine, however, to call C<< ->recv >> when the user of your module |
438 | requests it (i.e. if you create a http request object ad have a method |
727 | requests it (i.e. if you create a http request object ad have a method |
439 | called C<results> that returns the results, it should call C<< ->wait >> |
728 | called C<results> that returns the results, it should call C<< ->recv >> |
440 | freely, as the user of your module knows what she is doing. always). |
729 | freely, as the user of your module knows what she is doing. always). |
441 | |
730 | |
442 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
731 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
443 | |
732 | |
444 | There will always be a single main program - the only place that should |
733 | There will always be a single main program - the only place that should |
… | |
… | |
446 | |
735 | |
447 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
736 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
448 | do anything special (it does not need to be event-based) and let AnyEvent |
737 | do anything special (it does not need to be event-based) and let AnyEvent |
449 | decide which implementation to chose if some module relies on it. |
738 | decide which implementation to chose if some module relies on it. |
450 | |
739 | |
451 | If the main program relies on a specific event model. For example, in |
740 | If the main program relies on a specific event model - for example, in |
452 | Gtk2 programs you have to rely on the Glib module. You should load the |
741 | Gtk2 programs you have to rely on the Glib module - you should load the |
453 | event module before loading AnyEvent or any module that uses it: generally |
742 | event module before loading AnyEvent or any module that uses it: generally |
454 | speaking, you should load it as early as possible. The reason is that |
743 | speaking, you should load it as early as possible. The reason is that |
455 | modules might create watchers when they are loaded, and AnyEvent will |
744 | modules might create watchers when they are loaded, and AnyEvent will |
456 | decide on the event model to use as soon as it creates watchers, and it |
745 | decide on the event model to use as soon as it creates watchers, and it |
457 | might chose the wrong one unless you load the correct one yourself. |
746 | might chose the wrong one unless you load the correct one yourself. |
458 | |
747 | |
459 | You can chose to use a rather inefficient pure-perl implementation by |
748 | You can chose to use a pure-perl implementation by loading the |
460 | loading the C<AnyEvent::Impl::Perl> module, which gives you similar |
749 | C<AnyEvent::Impl::Perl> module, which gives you similar behaviour |
461 | behaviour everywhere, but letting AnyEvent chose is generally better. |
750 | everywhere, but letting AnyEvent chose the model is generally better. |
|
|
751 | |
|
|
752 | =head2 MAINLOOP EMULATION |
|
|
753 | |
|
|
754 | Sometimes (often for short test scripts, or even standalone programs who |
|
|
755 | only want to use AnyEvent), you do not want to run a specific event loop. |
|
|
756 | |
|
|
757 | In that case, you can use a condition variable like this: |
|
|
758 | |
|
|
759 | AnyEvent->condvar->recv; |
|
|
760 | |
|
|
761 | This has the effect of entering the event loop and looping forever. |
|
|
762 | |
|
|
763 | Note that usually your program has some exit condition, in which case |
|
|
764 | it is better to use the "traditional" approach of storing a condition |
|
|
765 | variable somewhere, waiting for it, and sending it when the program should |
|
|
766 | exit cleanly. |
|
|
767 | |
|
|
768 | |
|
|
769 | =head1 OTHER MODULES |
|
|
770 | |
|
|
771 | The following is a non-exhaustive list of additional modules that use |
|
|
772 | AnyEvent and can therefore be mixed easily with other AnyEvent modules |
|
|
773 | in the same program. Some of the modules come with AnyEvent, some are |
|
|
774 | available via CPAN. |
|
|
775 | |
|
|
776 | =over 4 |
|
|
777 | |
|
|
778 | =item L<AnyEvent::Util> |
|
|
779 | |
|
|
780 | Contains various utility functions that replace often-used but blocking |
|
|
781 | functions such as C<inet_aton> by event-/callback-based versions. |
|
|
782 | |
|
|
783 | =item L<AnyEvent::Socket> |
|
|
784 | |
|
|
785 | Provides various utility functions for (internet protocol) sockets, |
|
|
786 | addresses and name resolution. Also functions to create non-blocking tcp |
|
|
787 | connections or tcp servers, with IPv6 and SRV record support and more. |
|
|
788 | |
|
|
789 | =item L<AnyEvent::Handle> |
|
|
790 | |
|
|
791 | Provide read and write buffers, manages watchers for reads and writes, |
|
|
792 | supports raw and formatted I/O, I/O queued and fully transparent and |
|
|
793 | non-blocking SSL/TLS. |
|
|
794 | |
|
|
795 | =item L<AnyEvent::DNS> |
|
|
796 | |
|
|
797 | Provides rich asynchronous DNS resolver capabilities. |
|
|
798 | |
|
|
799 | =item L<AnyEvent::HTTP> |
|
|
800 | |
|
|
801 | A simple-to-use HTTP library that is capable of making a lot of concurrent |
|
|
802 | HTTP requests. |
|
|
803 | |
|
|
804 | =item L<AnyEvent::HTTPD> |
|
|
805 | |
|
|
806 | Provides a simple web application server framework. |
|
|
807 | |
|
|
808 | =item L<AnyEvent::FastPing> |
|
|
809 | |
|
|
810 | The fastest ping in the west. |
|
|
811 | |
|
|
812 | =item L<AnyEvent::DBI> |
|
|
813 | |
|
|
814 | Executes L<DBI> requests asynchronously in a proxy process. |
|
|
815 | |
|
|
816 | =item L<AnyEvent::AIO> |
|
|
817 | |
|
|
818 | Truly asynchronous I/O, should be in the toolbox of every event |
|
|
819 | programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent |
|
|
820 | together. |
|
|
821 | |
|
|
822 | =item L<AnyEvent::BDB> |
|
|
823 | |
|
|
824 | Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses |
|
|
825 | L<BDB> and AnyEvent together. |
|
|
826 | |
|
|
827 | =item L<AnyEvent::GPSD> |
|
|
828 | |
|
|
829 | A non-blocking interface to gpsd, a daemon delivering GPS information. |
|
|
830 | |
|
|
831 | =item L<AnyEvent::IGS> |
|
|
832 | |
|
|
833 | A non-blocking interface to the Internet Go Server protocol (used by |
|
|
834 | L<App::IGS>). |
|
|
835 | |
|
|
836 | =item L<AnyEvent::IRC> |
|
|
837 | |
|
|
838 | AnyEvent based IRC client module family (replacing the older Net::IRC3). |
|
|
839 | |
|
|
840 | =item L<Net::XMPP2> |
|
|
841 | |
|
|
842 | AnyEvent based XMPP (Jabber protocol) module family. |
|
|
843 | |
|
|
844 | =item L<Net::FCP> |
|
|
845 | |
|
|
846 | AnyEvent-based implementation of the Freenet Client Protocol, birthplace |
|
|
847 | of AnyEvent. |
|
|
848 | |
|
|
849 | =item L<Event::ExecFlow> |
|
|
850 | |
|
|
851 | High level API for event-based execution flow control. |
|
|
852 | |
|
|
853 | =item L<Coro> |
|
|
854 | |
|
|
855 | Has special support for AnyEvent via L<Coro::AnyEvent>. |
|
|
856 | |
|
|
857 | =item L<IO::Lambda> |
|
|
858 | |
|
|
859 | The lambda approach to I/O - don't ask, look there. Can use AnyEvent. |
|
|
860 | |
|
|
861 | =back |
462 | |
862 | |
463 | =cut |
863 | =cut |
464 | |
864 | |
465 | package AnyEvent; |
865 | package AnyEvent; |
466 | |
866 | |
467 | no warnings; |
867 | no warnings; |
468 | use strict; |
868 | use strict qw(vars subs); |
469 | |
869 | |
470 | use Carp; |
870 | use Carp; |
471 | |
871 | |
472 | our $VERSION = '3.3'; |
872 | our $VERSION = 4.341; |
473 | our $MODEL; |
873 | our $MODEL; |
474 | |
874 | |
475 | our $AUTOLOAD; |
875 | our $AUTOLOAD; |
476 | our @ISA; |
876 | our @ISA; |
477 | |
877 | |
|
|
878 | our @REGISTRY; |
|
|
879 | |
|
|
880 | our $WIN32; |
|
|
881 | |
|
|
882 | BEGIN { |
|
|
883 | my $win32 = ! ! ($^O =~ /mswin32/i); |
|
|
884 | eval "sub WIN32(){ $win32 }"; |
|
|
885 | } |
|
|
886 | |
478 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
887 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
479 | |
888 | |
480 | our @REGISTRY; |
889 | our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred |
|
|
890 | |
|
|
891 | { |
|
|
892 | my $idx; |
|
|
893 | $PROTOCOL{$_} = ++$idx |
|
|
894 | for reverse split /\s*,\s*/, |
|
|
895 | $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; |
|
|
896 | } |
481 | |
897 | |
482 | my @models = ( |
898 | my @models = ( |
483 | [Coro::EV:: => AnyEvent::Impl::CoroEV::], |
|
|
484 | [Coro::Event:: => AnyEvent::Impl::CoroEvent::], |
|
|
485 | [EV:: => AnyEvent::Impl::EV::], |
899 | [EV:: => AnyEvent::Impl::EV::], |
486 | [Event:: => AnyEvent::Impl::Event::], |
900 | [Event:: => AnyEvent::Impl::Event::], |
487 | [Glib:: => AnyEvent::Impl::Glib::], |
|
|
488 | [Tk:: => AnyEvent::Impl::Tk::], |
|
|
489 | [Wx:: => AnyEvent::Impl::POE::], |
|
|
490 | [Prima:: => AnyEvent::Impl::POE::], |
|
|
491 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
901 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
492 | # everything below here will not be autoprobed as the pureperl backend should work everywhere |
902 | # everything below here will not be autoprobed |
|
|
903 | # as the pureperl backend should work everywhere |
|
|
904 | # and is usually faster |
|
|
905 | [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles |
|
|
906 | [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers |
493 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
907 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
494 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
908 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
495 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
909 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
|
|
910 | [Wx:: => AnyEvent::Impl::POE::], |
|
|
911 | [Prima:: => AnyEvent::Impl::POE::], |
496 | ); |
912 | ); |
497 | |
913 | |
498 | our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY); |
914 | our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY); |
|
|
915 | |
|
|
916 | our @post_detect; |
|
|
917 | |
|
|
918 | sub post_detect(&) { |
|
|
919 | my ($cb) = @_; |
|
|
920 | |
|
|
921 | if ($MODEL) { |
|
|
922 | $cb->(); |
|
|
923 | |
|
|
924 | 1 |
|
|
925 | } else { |
|
|
926 | push @post_detect, $cb; |
|
|
927 | |
|
|
928 | defined wantarray |
|
|
929 | ? bless \$cb, "AnyEvent::Util::PostDetect" |
|
|
930 | : () |
|
|
931 | } |
|
|
932 | } |
|
|
933 | |
|
|
934 | sub AnyEvent::Util::PostDetect::DESTROY { |
|
|
935 | @post_detect = grep $_ != ${$_[0]}, @post_detect; |
|
|
936 | } |
499 | |
937 | |
500 | sub detect() { |
938 | sub detect() { |
501 | unless ($MODEL) { |
939 | unless ($MODEL) { |
502 | no strict 'refs'; |
940 | no strict 'refs'; |
|
|
941 | local $SIG{__DIE__}; |
503 | |
942 | |
504 | if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { |
943 | if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { |
505 | my $model = "AnyEvent::Impl::$1"; |
944 | my $model = "AnyEvent::Impl::$1"; |
506 | if (eval "require $model") { |
945 | if (eval "require $model") { |
507 | $MODEL = $model; |
946 | $MODEL = $model; |
… | |
… | |
537 | last; |
976 | last; |
538 | } |
977 | } |
539 | } |
978 | } |
540 | |
979 | |
541 | $MODEL |
980 | $MODEL |
542 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib."; |
981 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib."; |
543 | } |
982 | } |
544 | } |
983 | } |
545 | |
984 | |
|
|
985 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
|
|
986 | |
546 | unshift @ISA, $MODEL; |
987 | unshift @ISA, $MODEL; |
547 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
988 | |
|
|
989 | require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT}; |
|
|
990 | |
|
|
991 | (shift @post_detect)->() while @post_detect; |
548 | } |
992 | } |
549 | |
993 | |
550 | $MODEL |
994 | $MODEL |
551 | } |
995 | } |
552 | |
996 | |
… | |
… | |
560 | |
1004 | |
561 | my $class = shift; |
1005 | my $class = shift; |
562 | $class->$func (@_); |
1006 | $class->$func (@_); |
563 | } |
1007 | } |
564 | |
1008 | |
|
|
1009 | # utility function to dup a filehandle. this is used by many backends |
|
|
1010 | # to support binding more than one watcher per filehandle (they usually |
|
|
1011 | # allow only one watcher per fd, so we dup it to get a different one). |
|
|
1012 | sub _dupfh($$$$) { |
|
|
1013 | my ($poll, $fh, $r, $w) = @_; |
|
|
1014 | |
|
|
1015 | # cygwin requires the fh mode to be matching, unix doesn't |
|
|
1016 | my ($rw, $mode) = $poll eq "r" ? ($r, "<") |
|
|
1017 | : $poll eq "w" ? ($w, ">") |
|
|
1018 | : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'"; |
|
|
1019 | |
|
|
1020 | open my $fh2, "$mode&" . fileno $fh |
|
|
1021 | or die "cannot dup() filehandle: $!"; |
|
|
1022 | |
|
|
1023 | # we assume CLOEXEC is already set by perl in all important cases |
|
|
1024 | |
|
|
1025 | ($fh2, $rw) |
|
|
1026 | } |
|
|
1027 | |
565 | package AnyEvent::Base; |
1028 | package AnyEvent::Base; |
566 | |
1029 | |
|
|
1030 | # default implementation for now and time |
|
|
1031 | |
|
|
1032 | BEGIN { |
|
|
1033 | if (eval "use Time::HiRes (); time (); 1") { |
|
|
1034 | *_time = \&Time::HiRes::time; |
|
|
1035 | # if (eval "use POSIX (); (POSIX::times())... |
|
|
1036 | } else { |
|
|
1037 | *_time = sub { time }; # epic fail |
|
|
1038 | } |
|
|
1039 | } |
|
|
1040 | |
|
|
1041 | sub time { _time } |
|
|
1042 | sub now { _time } |
|
|
1043 | |
567 | # default implementation for ->condvar, ->wait, ->broadcast |
1044 | # default implementation for ->condvar |
568 | |
1045 | |
569 | sub condvar { |
1046 | sub condvar { |
570 | bless \my $flag, "AnyEvent::Base::CondVar" |
1047 | bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: |
571 | } |
|
|
572 | |
|
|
573 | sub AnyEvent::Base::CondVar::broadcast { |
|
|
574 | ${$_[0]}++; |
|
|
575 | } |
|
|
576 | |
|
|
577 | sub AnyEvent::Base::CondVar::wait { |
|
|
578 | AnyEvent->one_event while !${$_[0]}; |
|
|
579 | } |
1048 | } |
580 | |
1049 | |
581 | # default implementation for ->signal |
1050 | # default implementation for ->signal |
582 | |
1051 | |
583 | our %SIG_CB; |
1052 | our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); |
|
|
1053 | |
|
|
1054 | sub _signal_exec { |
|
|
1055 | while (%SIG_EV) { |
|
|
1056 | sysread $SIGPIPE_R, my $dummy, 4; |
|
|
1057 | for (keys %SIG_EV) { |
|
|
1058 | delete $SIG_EV{$_}; |
|
|
1059 | $_->() for values %{ $SIG_CB{$_} || {} }; |
|
|
1060 | } |
|
|
1061 | } |
|
|
1062 | } |
584 | |
1063 | |
585 | sub signal { |
1064 | sub signal { |
586 | my (undef, %arg) = @_; |
1065 | my (undef, %arg) = @_; |
587 | |
1066 | |
|
|
1067 | unless ($SIGPIPE_R) { |
|
|
1068 | if (AnyEvent::WIN32) { |
|
|
1069 | ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe (); |
|
|
1070 | AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R; |
|
|
1071 | AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case |
|
|
1072 | } else { |
|
|
1073 | pipe $SIGPIPE_R, $SIGPIPE_W; |
|
|
1074 | require Fcntl; |
|
|
1075 | fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R; |
|
|
1076 | fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case |
|
|
1077 | } |
|
|
1078 | |
|
|
1079 | $SIGPIPE_R |
|
|
1080 | or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; |
|
|
1081 | |
|
|
1082 | $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec); |
|
|
1083 | } |
|
|
1084 | |
588 | my $signal = uc $arg{signal} |
1085 | my $signal = uc $arg{signal} |
589 | or Carp::croak "required option 'signal' is missing"; |
1086 | or Carp::croak "required option 'signal' is missing"; |
590 | |
1087 | |
591 | $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; |
1088 | $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; |
592 | $SIG{$signal} ||= sub { |
1089 | $SIG{$signal} ||= sub { |
593 | $_->() for values %{ $SIG_CB{$signal} || {} }; |
1090 | syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; |
|
|
1091 | undef $SIG_EV{$signal}; |
594 | }; |
1092 | }; |
595 | |
1093 | |
596 | bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" |
1094 | bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" |
597 | } |
1095 | } |
598 | |
1096 | |
599 | sub AnyEvent::Base::Signal::DESTROY { |
1097 | sub AnyEvent::Base::Signal::DESTROY { |
600 | my ($signal, $cb) = @{$_[0]}; |
1098 | my ($signal, $cb) = @{$_[0]}; |
601 | |
1099 | |
602 | delete $SIG_CB{$signal}{$cb}; |
1100 | delete $SIG_CB{$signal}{$cb}; |
603 | |
1101 | |
604 | $SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} }; |
1102 | delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} }; |
605 | } |
1103 | } |
606 | |
1104 | |
607 | # default implementation for ->child |
1105 | # default implementation for ->child |
608 | |
1106 | |
609 | our %PID_CB; |
1107 | our %PID_CB; |
… | |
… | |
636 | or Carp::croak "required option 'pid' is missing"; |
1134 | or Carp::croak "required option 'pid' is missing"; |
637 | |
1135 | |
638 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
1136 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
639 | |
1137 | |
640 | unless ($WNOHANG) { |
1138 | unless ($WNOHANG) { |
641 | $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1; |
1139 | $WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; |
642 | } |
1140 | } |
643 | |
1141 | |
644 | unless ($CHLD_W) { |
1142 | unless ($CHLD_W) { |
645 | $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); |
1143 | $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); |
646 | # child could be a zombie already, so make at least one round |
1144 | # child could be a zombie already, so make at least one round |
… | |
… | |
656 | delete $PID_CB{$pid}{$cb}; |
1154 | delete $PID_CB{$pid}{$cb}; |
657 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
1155 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
658 | |
1156 | |
659 | undef $CHLD_W unless keys %PID_CB; |
1157 | undef $CHLD_W unless keys %PID_CB; |
660 | } |
1158 | } |
|
|
1159 | |
|
|
1160 | package AnyEvent::CondVar; |
|
|
1161 | |
|
|
1162 | our @ISA = AnyEvent::CondVar::Base::; |
|
|
1163 | |
|
|
1164 | package AnyEvent::CondVar::Base; |
|
|
1165 | |
|
|
1166 | use overload |
|
|
1167 | '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, |
|
|
1168 | fallback => 1; |
|
|
1169 | |
|
|
1170 | sub _send { |
|
|
1171 | # nop |
|
|
1172 | } |
|
|
1173 | |
|
|
1174 | sub send { |
|
|
1175 | my $cv = shift; |
|
|
1176 | $cv->{_ae_sent} = [@_]; |
|
|
1177 | (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb}; |
|
|
1178 | $cv->_send; |
|
|
1179 | } |
|
|
1180 | |
|
|
1181 | sub croak { |
|
|
1182 | $_[0]{_ae_croak} = $_[1]; |
|
|
1183 | $_[0]->send; |
|
|
1184 | } |
|
|
1185 | |
|
|
1186 | sub ready { |
|
|
1187 | $_[0]{_ae_sent} |
|
|
1188 | } |
|
|
1189 | |
|
|
1190 | sub _wait { |
|
|
1191 | AnyEvent->one_event while !$_[0]{_ae_sent}; |
|
|
1192 | } |
|
|
1193 | |
|
|
1194 | sub recv { |
|
|
1195 | $_[0]->_wait; |
|
|
1196 | |
|
|
1197 | Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; |
|
|
1198 | wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] |
|
|
1199 | } |
|
|
1200 | |
|
|
1201 | sub cb { |
|
|
1202 | $_[0]{_ae_cb} = $_[1] if @_ > 1; |
|
|
1203 | $_[0]{_ae_cb} |
|
|
1204 | } |
|
|
1205 | |
|
|
1206 | sub begin { |
|
|
1207 | ++$_[0]{_ae_counter}; |
|
|
1208 | $_[0]{_ae_end_cb} = $_[1] if @_ > 1; |
|
|
1209 | } |
|
|
1210 | |
|
|
1211 | sub end { |
|
|
1212 | return if --$_[0]{_ae_counter}; |
|
|
1213 | &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } }; |
|
|
1214 | } |
|
|
1215 | |
|
|
1216 | # undocumented/compatibility with pre-3.4 |
|
|
1217 | *broadcast = \&send; |
|
|
1218 | *wait = \&_wait; |
|
|
1219 | |
|
|
1220 | =head1 ERROR AND EXCEPTION HANDLING |
|
|
1221 | |
|
|
1222 | In general, AnyEvent does not do any error handling - it relies on the |
|
|
1223 | caller to do that if required. The L<AnyEvent::Strict> module (see also |
|
|
1224 | the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict |
|
|
1225 | checking of all AnyEvent methods, however, which is highly useful during |
|
|
1226 | development. |
|
|
1227 | |
|
|
1228 | As for exception handling (i.e. runtime errors and exceptions thrown while |
|
|
1229 | executing a callback), this is not only highly event-loop specific, but |
|
|
1230 | also not in any way wrapped by this module, as this is the job of the main |
|
|
1231 | program. |
|
|
1232 | |
|
|
1233 | The pure perl event loop simply re-throws the exception (usually |
|
|
1234 | within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<< |
|
|
1235 | $Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and |
|
|
1236 | so on. |
|
|
1237 | |
|
|
1238 | =head1 ENVIRONMENT VARIABLES |
|
|
1239 | |
|
|
1240 | The following environment variables are used by this module or its |
|
|
1241 | submodules: |
|
|
1242 | |
|
|
1243 | =over 4 |
|
|
1244 | |
|
|
1245 | =item C<PERL_ANYEVENT_VERBOSE> |
|
|
1246 | |
|
|
1247 | By default, AnyEvent will be completely silent except in fatal |
|
|
1248 | conditions. You can set this environment variable to make AnyEvent more |
|
|
1249 | talkative. |
|
|
1250 | |
|
|
1251 | When set to C<1> or higher, causes AnyEvent to warn about unexpected |
|
|
1252 | conditions, such as not being able to load the event model specified by |
|
|
1253 | C<PERL_ANYEVENT_MODEL>. |
|
|
1254 | |
|
|
1255 | When set to C<2> or higher, cause AnyEvent to report to STDERR which event |
|
|
1256 | model it chooses. |
|
|
1257 | |
|
|
1258 | =item C<PERL_ANYEVENT_STRICT> |
|
|
1259 | |
|
|
1260 | AnyEvent does not do much argument checking by default, as thorough |
|
|
1261 | argument checking is very costly. Setting this variable to a true value |
|
|
1262 | will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly |
|
|
1263 | check the arguments passed to most method calls. If it finds any problems |
|
|
1264 | it will croak. |
|
|
1265 | |
|
|
1266 | In other words, enables "strict" mode. |
|
|
1267 | |
|
|
1268 | Unlike C<use strict>, it is definitely recommended ot keep it off in |
|
|
1269 | production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while |
|
|
1270 | developing programs can be very useful, however. |
|
|
1271 | |
|
|
1272 | =item C<PERL_ANYEVENT_MODEL> |
|
|
1273 | |
|
|
1274 | This can be used to specify the event model to be used by AnyEvent, before |
|
|
1275 | auto detection and -probing kicks in. It must be a string consisting |
|
|
1276 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
|
|
1277 | and the resulting module name is loaded and if the load was successful, |
|
|
1278 | used as event model. If it fails to load AnyEvent will proceed with |
|
|
1279 | auto detection and -probing. |
|
|
1280 | |
|
|
1281 | This functionality might change in future versions. |
|
|
1282 | |
|
|
1283 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
|
|
1284 | could start your program like this: |
|
|
1285 | |
|
|
1286 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
1287 | |
|
|
1288 | =item C<PERL_ANYEVENT_PROTOCOLS> |
|
|
1289 | |
|
|
1290 | Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences |
|
|
1291 | for IPv4 or IPv6. The default is unspecified (and might change, or be the result |
|
|
1292 | of auto probing). |
|
|
1293 | |
|
|
1294 | Must be set to a comma-separated list of protocols or address families, |
|
|
1295 | current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be |
|
|
1296 | used, and preference will be given to protocols mentioned earlier in the |
|
|
1297 | list. |
|
|
1298 | |
|
|
1299 | This variable can effectively be used for denial-of-service attacks |
|
|
1300 | against local programs (e.g. when setuid), although the impact is likely |
|
|
1301 | small, as the program has to handle conenction and other failures anyways. |
|
|
1302 | |
|
|
1303 | Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6, |
|
|
1304 | but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> |
|
|
1305 | - only support IPv4, never try to resolve or contact IPv6 |
|
|
1306 | addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or |
|
|
1307 | IPv6, but prefer IPv6 over IPv4. |
|
|
1308 | |
|
|
1309 | =item C<PERL_ANYEVENT_EDNS0> |
|
|
1310 | |
|
|
1311 | Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension |
|
|
1312 | for DNS. This extension is generally useful to reduce DNS traffic, but |
|
|
1313 | some (broken) firewalls drop such DNS packets, which is why it is off by |
|
|
1314 | default. |
|
|
1315 | |
|
|
1316 | Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce |
|
|
1317 | EDNS0 in its DNS requests. |
|
|
1318 | |
|
|
1319 | =item C<PERL_ANYEVENT_MAX_FORKS> |
|
|
1320 | |
|
|
1321 | The maximum number of child processes that C<AnyEvent::Util::fork_call> |
|
|
1322 | will create in parallel. |
|
|
1323 | |
|
|
1324 | =back |
661 | |
1325 | |
662 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
1326 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
663 | |
1327 | |
664 | This is an advanced topic that you do not normally need to use AnyEvent in |
1328 | This is an advanced topic that you do not normally need to use AnyEvent in |
665 | a module. This section is only of use to event loop authors who want to |
1329 | a module. This section is only of use to event loop authors who want to |
… | |
… | |
699 | |
1363 | |
700 | I<rxvt-unicode> also cheats a bit by not providing blocking access to |
1364 | I<rxvt-unicode> also cheats a bit by not providing blocking access to |
701 | condition variables: code blocking while waiting for a condition will |
1365 | condition variables: code blocking while waiting for a condition will |
702 | C<die>. This still works with most modules/usages, and blocking calls must |
1366 | C<die>. This still works with most modules/usages, and blocking calls must |
703 | not be done in an interactive application, so it makes sense. |
1367 | not be done in an interactive application, so it makes sense. |
704 | |
|
|
705 | =head1 ENVIRONMENT VARIABLES |
|
|
706 | |
|
|
707 | The following environment variables are used by this module: |
|
|
708 | |
|
|
709 | =over 4 |
|
|
710 | |
|
|
711 | =item C<PERL_ANYEVENT_VERBOSE> |
|
|
712 | |
|
|
713 | By default, AnyEvent will be completely silent except in fatal |
|
|
714 | conditions. You can set this environment variable to make AnyEvent more |
|
|
715 | talkative. |
|
|
716 | |
|
|
717 | When set to C<1> or higher, causes AnyEvent to warn about unexpected |
|
|
718 | conditions, such as not being able to load the event model specified by |
|
|
719 | C<PERL_ANYEVENT_MODEL>. |
|
|
720 | |
|
|
721 | When set to C<2> or higher, cause AnyEvent to report to STDERR which event |
|
|
722 | model it chooses. |
|
|
723 | |
|
|
724 | =item C<PERL_ANYEVENT_MODEL> |
|
|
725 | |
|
|
726 | This can be used to specify the event model to be used by AnyEvent, before |
|
|
727 | autodetection and -probing kicks in. It must be a string consisting |
|
|
728 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
|
|
729 | and the resulting module name is loaded and if the load was successful, |
|
|
730 | used as event model. If it fails to load AnyEvent will proceed with |
|
|
731 | autodetection and -probing. |
|
|
732 | |
|
|
733 | This functionality might change in future versions. |
|
|
734 | |
|
|
735 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
|
|
736 | could start your program like this: |
|
|
737 | |
|
|
738 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
739 | |
|
|
740 | =back |
|
|
741 | |
1368 | |
742 | =head1 EXAMPLE PROGRAM |
1369 | =head1 EXAMPLE PROGRAM |
743 | |
1370 | |
744 | The following program uses an I/O watcher to read data from STDIN, a timer |
1371 | The following program uses an I/O watcher to read data from STDIN, a timer |
745 | to display a message once per second, and a condition variable to quit the |
1372 | to display a message once per second, and a condition variable to quit the |
… | |
… | |
754 | poll => 'r', |
1381 | poll => 'r', |
755 | cb => sub { |
1382 | cb => sub { |
756 | warn "io event <$_[0]>\n"; # will always output <r> |
1383 | warn "io event <$_[0]>\n"; # will always output <r> |
757 | chomp (my $input = <STDIN>); # read a line |
1384 | chomp (my $input = <STDIN>); # read a line |
758 | warn "read: $input\n"; # output what has been read |
1385 | warn "read: $input\n"; # output what has been read |
759 | $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i |
1386 | $cv->send if $input =~ /^q/i; # quit program if /^q/i |
760 | }, |
1387 | }, |
761 | ); |
1388 | ); |
762 | |
1389 | |
763 | my $time_watcher; # can only be used once |
1390 | my $time_watcher; # can only be used once |
764 | |
1391 | |
… | |
… | |
769 | }); |
1396 | }); |
770 | } |
1397 | } |
771 | |
1398 | |
772 | new_timer; # create first timer |
1399 | new_timer; # create first timer |
773 | |
1400 | |
774 | $cv->wait; # wait until user enters /^q/i |
1401 | $cv->recv; # wait until user enters /^q/i |
775 | |
1402 | |
776 | =head1 REAL-WORLD EXAMPLE |
1403 | =head1 REAL-WORLD EXAMPLE |
777 | |
1404 | |
778 | Consider the L<Net::FCP> module. It features (among others) the following |
1405 | Consider the L<Net::FCP> module. It features (among others) the following |
779 | API calls, which are to freenet what HTTP GET requests are to http: |
1406 | API calls, which are to freenet what HTTP GET requests are to http: |
… | |
… | |
829 | syswrite $txn->{fh}, $txn->{request} |
1456 | syswrite $txn->{fh}, $txn->{request} |
830 | or die "connection or write error"; |
1457 | or die "connection or write error"; |
831 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
1458 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
832 | |
1459 | |
833 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
1460 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
834 | result and signals any possible waiters that the request ahs finished: |
1461 | result and signals any possible waiters that the request has finished: |
835 | |
1462 | |
836 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
1463 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
837 | |
1464 | |
838 | if (end-of-file or data complete) { |
1465 | if (end-of-file or data complete) { |
839 | $txn->{result} = $txn->{buf}; |
1466 | $txn->{result} = $txn->{buf}; |
840 | $txn->{finished}->broadcast; |
1467 | $txn->{finished}->send; |
841 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
1468 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
842 | } |
1469 | } |
843 | |
1470 | |
844 | The C<result> method, finally, just waits for the finished signal (if the |
1471 | The C<result> method, finally, just waits for the finished signal (if the |
845 | request was already finished, it doesn't wait, of course, and returns the |
1472 | request was already finished, it doesn't wait, of course, and returns the |
846 | data: |
1473 | data: |
847 | |
1474 | |
848 | $txn->{finished}->wait; |
1475 | $txn->{finished}->recv; |
849 | return $txn->{result}; |
1476 | return $txn->{result}; |
850 | |
1477 | |
851 | The actual code goes further and collects all errors (C<die>s, exceptions) |
1478 | The actual code goes further and collects all errors (C<die>s, exceptions) |
852 | that occured during request processing. The C<result> method detects |
1479 | that occurred during request processing. The C<result> method detects |
853 | whether an exception as thrown (it is stored inside the $txn object) |
1480 | whether an exception as thrown (it is stored inside the $txn object) |
854 | and just throws the exception, which means connection errors and other |
1481 | and just throws the exception, which means connection errors and other |
855 | problems get reported tot he code that tries to use the result, not in a |
1482 | problems get reported tot he code that tries to use the result, not in a |
856 | random callback. |
1483 | random callback. |
857 | |
1484 | |
… | |
… | |
888 | |
1515 | |
889 | my $quit = AnyEvent->condvar; |
1516 | my $quit = AnyEvent->condvar; |
890 | |
1517 | |
891 | $fcp->txn_client_get ($url)->cb (sub { |
1518 | $fcp->txn_client_get ($url)->cb (sub { |
892 | ... |
1519 | ... |
893 | $quit->broadcast; |
1520 | $quit->send; |
894 | }); |
1521 | }); |
895 | |
1522 | |
896 | $quit->wait; |
1523 | $quit->recv; |
897 | |
1524 | |
898 | |
1525 | |
899 | =head1 BENCHMARKS |
1526 | =head1 BENCHMARKS |
900 | |
1527 | |
901 | To give you an idea of the performance and overheads that AnyEvent adds |
1528 | To give you an idea of the performance and overheads that AnyEvent adds |
… | |
… | |
903 | of various event loops I prepared some benchmarks. |
1530 | of various event loops I prepared some benchmarks. |
904 | |
1531 | |
905 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
1532 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
906 | |
1533 | |
907 | Here is a benchmark of various supported event models used natively and |
1534 | Here is a benchmark of various supported event models used natively and |
908 | through anyevent. The benchmark creates a lot of timers (with a zero |
1535 | through AnyEvent. The benchmark creates a lot of timers (with a zero |
909 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
1536 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
910 | which it is), lets them fire exactly once and destroys them again. |
1537 | which it is), lets them fire exactly once and destroys them again. |
911 | |
1538 | |
912 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
1539 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
913 | distribution. |
1540 | distribution. |
… | |
… | |
930 | all watchers, to avoid adding memory overhead. That means closure creation |
1557 | all watchers, to avoid adding memory overhead. That means closure creation |
931 | and memory usage is not included in the figures. |
1558 | and memory usage is not included in the figures. |
932 | |
1559 | |
933 | I<invoke> is the time, in microseconds, used to invoke a simple |
1560 | I<invoke> is the time, in microseconds, used to invoke a simple |
934 | callback. The callback simply counts down a Perl variable and after it was |
1561 | callback. The callback simply counts down a Perl variable and after it was |
935 | invoked "watcher" times, it would C<< ->broadcast >> a condvar once to |
1562 | invoked "watcher" times, it would C<< ->send >> a condvar once to |
936 | signal the end of this phase. |
1563 | signal the end of this phase. |
937 | |
1564 | |
938 | I<destroy> is the time, in microseconds, that it takes to destroy a single |
1565 | I<destroy> is the time, in microseconds, that it takes to destroy a single |
939 | watcher. |
1566 | watcher. |
940 | |
1567 | |
941 | =head3 Results |
1568 | =head3 Results |
942 | |
1569 | |
943 | name watchers bytes create invoke destroy comment |
1570 | name watchers bytes create invoke destroy comment |
944 | EV/EV 400000 244 0.56 0.46 0.31 EV native interface |
1571 | EV/EV 400000 224 0.47 0.35 0.27 EV native interface |
945 | EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers |
1572 | EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers |
946 | CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal |
1573 | CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal |
947 | Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation |
1574 | Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation |
948 | Event/Event 16000 516 31.88 31.30 0.85 Event native interface |
1575 | Event/Event 16000 517 32.20 31.80 0.81 Event native interface |
949 | Event/Any 16000 936 39.17 33.63 1.43 Event + AnyEvent watchers |
1576 | Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers |
950 | Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour |
1577 | Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour |
951 | Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers |
1578 | Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers |
952 | POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event |
1579 | POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event |
953 | POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select |
1580 | POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select |
954 | |
1581 | |
955 | =head3 Discussion |
1582 | =head3 Discussion |
956 | |
1583 | |
957 | The benchmark does I<not> measure scalability of the event loop very |
1584 | The benchmark does I<not> measure scalability of the event loop very |
958 | well. For example, a select-based event loop (such as the pure perl one) |
1585 | well. For example, a select-based event loop (such as the pure perl one) |
959 | can never compete with an event loop that uses epoll when the number of |
1586 | can never compete with an event loop that uses epoll when the number of |
960 | file descriptors grows high. In this benchmark, all events become ready at |
1587 | file descriptors grows high. In this benchmark, all events become ready at |
961 | the same time, so select/poll-based implementations get an unnatural speed |
1588 | the same time, so select/poll-based implementations get an unnatural speed |
962 | boost. |
1589 | boost. |
|
|
1590 | |
|
|
1591 | Also, note that the number of watchers usually has a nonlinear effect on |
|
|
1592 | overall speed, that is, creating twice as many watchers doesn't take twice |
|
|
1593 | the time - usually it takes longer. This puts event loops tested with a |
|
|
1594 | higher number of watchers at a disadvantage. |
|
|
1595 | |
|
|
1596 | To put the range of results into perspective, consider that on the |
|
|
1597 | benchmark machine, handling an event takes roughly 1600 CPU cycles with |
|
|
1598 | EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU |
|
|
1599 | cycles with POE. |
963 | |
1600 | |
964 | C<EV> is the sole leader regarding speed and memory use, which are both |
1601 | C<EV> is the sole leader regarding speed and memory use, which are both |
965 | maximal/minimal, respectively. Even when going through AnyEvent, it uses |
1602 | maximal/minimal, respectively. Even when going through AnyEvent, it uses |
966 | far less memory than any other event loop and is still faster than Event |
1603 | far less memory than any other event loop and is still faster than Event |
967 | natively. |
1604 | natively. |
… | |
… | |
990 | file descriptor is dup()ed for each watcher. This shows that the dup() |
1627 | file descriptor is dup()ed for each watcher. This shows that the dup() |
991 | employed by some adaptors is not a big performance issue (it does incur a |
1628 | employed by some adaptors is not a big performance issue (it does incur a |
992 | hidden memory cost inside the kernel which is not reflected in the figures |
1629 | hidden memory cost inside the kernel which is not reflected in the figures |
993 | above). |
1630 | above). |
994 | |
1631 | |
995 | C<POE>, regardless of underlying event loop (whether using its pure |
1632 | C<POE>, regardless of underlying event loop (whether using its pure perl |
996 | perl select-based backend or the Event module, the POE-EV backend |
1633 | select-based backend or the Event module, the POE-EV backend couldn't |
997 | couldn't be tested because it wasn't working) shows abysmal performance |
1634 | be tested because it wasn't working) shows abysmal performance and |
998 | and memory usage: Watchers use almost 30 times as much memory as |
1635 | memory usage with AnyEvent: Watchers use almost 30 times as much memory |
999 | EV watchers, and 10 times as much memory as Event (the high memory |
1636 | as EV watchers, and 10 times as much memory as Event (the high memory |
1000 | requirements are caused by requiring a session for each watcher). Watcher |
1637 | requirements are caused by requiring a session for each watcher). Watcher |
1001 | invocation speed is almost 900 times slower than with AnyEvent's pure perl |
1638 | invocation speed is almost 900 times slower than with AnyEvent's pure perl |
|
|
1639 | implementation. |
|
|
1640 | |
1002 | implementation. The design of the POE adaptor class in AnyEvent can not |
1641 | The design of the POE adaptor class in AnyEvent can not really account |
1003 | really account for this, as session creation overhead is small compared |
1642 | for the performance issues, though, as session creation overhead is |
1004 | to execution of the state machine, which is coded pretty optimally within |
1643 | small compared to execution of the state machine, which is coded pretty |
1005 | L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow. |
1644 | optimally within L<AnyEvent::Impl::POE> (and while everybody agrees that |
|
|
1645 | using multiple sessions is not a good approach, especially regarding |
|
|
1646 | memory usage, even the author of POE could not come up with a faster |
|
|
1647 | design). |
1006 | |
1648 | |
1007 | =head3 Summary |
1649 | =head3 Summary |
1008 | |
1650 | |
1009 | =over 4 |
1651 | =over 4 |
1010 | |
1652 | |
… | |
… | |
1021 | |
1663 | |
1022 | =back |
1664 | =back |
1023 | |
1665 | |
1024 | =head2 BENCHMARKING THE LARGE SERVER CASE |
1666 | =head2 BENCHMARKING THE LARGE SERVER CASE |
1025 | |
1667 | |
1026 | This benchmark atcually benchmarks the event loop itself. It works by |
1668 | This benchmark actually benchmarks the event loop itself. It works by |
1027 | creating a number of "servers": each server consists of a socketpair, a |
1669 | creating a number of "servers": each server consists of a socket pair, a |
1028 | timeout watcher that gets reset on activity (but never fires), and an I/O |
1670 | timeout watcher that gets reset on activity (but never fires), and an I/O |
1029 | watcher waiting for input on one side of the socket. Each time the socket |
1671 | watcher waiting for input on one side of the socket. Each time the socket |
1030 | watcher reads a byte it will write that byte to a random other "server". |
1672 | watcher reads a byte it will write that byte to a random other "server". |
1031 | |
1673 | |
1032 | The effect is that there will be a lot of I/O watchers, only part of which |
1674 | The effect is that there will be a lot of I/O watchers, only part of which |
1033 | are active at any one point (so there is a constant number of active |
1675 | are active at any one point (so there is a constant number of active |
1034 | fds for each loop iterstaion, but which fds these are is random). The |
1676 | fds for each loop iteration, but which fds these are is random). The |
1035 | timeout is reset each time something is read because that reflects how |
1677 | timeout is reset each time something is read because that reflects how |
1036 | most timeouts work (and puts extra pressure on the event loops). |
1678 | most timeouts work (and puts extra pressure on the event loops). |
1037 | |
1679 | |
1038 | In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100 |
1680 | In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 |
1039 | (1%) are active. This mirrors the activity of large servers with many |
1681 | (1%) are active. This mirrors the activity of large servers with many |
1040 | connections, most of which are idle at any one point in time. |
1682 | connections, most of which are idle at any one point in time. |
1041 | |
1683 | |
1042 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
1684 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
1043 | distribution. |
1685 | distribution. |
1044 | |
1686 | |
1045 | =head3 Explanation of the columns |
1687 | =head3 Explanation of the columns |
1046 | |
1688 | |
1047 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
1689 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
1048 | eahc server has a read and write socket end). |
1690 | each server has a read and write socket end). |
1049 | |
1691 | |
1050 | I<create> is the time it takes to create a socketpair (which is |
1692 | I<create> is the time it takes to create a socket pair (which is |
1051 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
1693 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
1052 | |
1694 | |
1053 | I<request>, the most important value, is the time it takes to handle a |
1695 | I<request>, the most important value, is the time it takes to handle a |
1054 | single "request", that is, reading the token from the pipe and forwarding |
1696 | single "request", that is, reading the token from the pipe and forwarding |
1055 | it to another server. This includes deleting the old timeout and creating |
1697 | it to another server. This includes deleting the old timeout and creating |
… | |
… | |
1057 | |
1699 | |
1058 | =head3 Results |
1700 | =head3 Results |
1059 | |
1701 | |
1060 | name sockets create request |
1702 | name sockets create request |
1061 | EV 20000 69.01 11.16 |
1703 | EV 20000 69.01 11.16 |
1062 | Perl 20000 75.28 112.76 |
1704 | Perl 20000 73.32 35.87 |
1063 | Event 20000 212.62 257.32 |
1705 | Event 20000 212.62 257.32 |
1064 | Glib 20000 651.16 1896.30 |
1706 | Glib 20000 651.16 1896.30 |
1065 | POE 20000 349.67 12317.24 uses POE::Loop::Event |
1707 | POE 20000 349.67 12317.24 uses POE::Loop::Event |
1066 | |
1708 | |
1067 | =head3 Discussion |
1709 | =head3 Discussion |
… | |
… | |
1089 | |
1731 | |
1090 | =head3 Summary |
1732 | =head3 Summary |
1091 | |
1733 | |
1092 | =over 4 |
1734 | =over 4 |
1093 | |
1735 | |
1094 | =item * The pure perl implementation performs extremely well, considering |
1736 | =item * The pure perl implementation performs extremely well. |
1095 | that it uses select. |
|
|
1096 | |
1737 | |
1097 | =item * Avoid Glib or POE in large projects where performance matters. |
1738 | =item * Avoid Glib or POE in large projects where performance matters. |
1098 | |
1739 | |
1099 | =back |
1740 | =back |
1100 | |
1741 | |
… | |
… | |
1113 | |
1754 | |
1114 | =head3 Results |
1755 | =head3 Results |
1115 | |
1756 | |
1116 | name sockets create request |
1757 | name sockets create request |
1117 | EV 16 20.00 6.54 |
1758 | EV 16 20.00 6.54 |
|
|
1759 | Perl 16 25.75 12.62 |
1118 | Event 16 81.27 35.86 |
1760 | Event 16 81.27 35.86 |
1119 | Glib 16 32.63 15.48 |
1761 | Glib 16 32.63 15.48 |
1120 | Perl 16 24.62 162.37 |
|
|
1121 | POE 16 261.87 276.28 uses POE::Loop::Event |
1762 | POE 16 261.87 276.28 uses POE::Loop::Event |
1122 | |
1763 | |
1123 | =head3 Discussion |
1764 | =head3 Discussion |
1124 | |
1765 | |
1125 | The benchmark tries to test the performance of a typical small |
1766 | The benchmark tries to test the performance of a typical small |
1126 | server. While knowing how various event loops perform is interesting, keep |
1767 | server. While knowing how various event loops perform is interesting, keep |
1127 | in mind that their overhead in this case is usually not as important, due |
1768 | in mind that their overhead in this case is usually not as important, due |
1128 | to the small absolute number of watchers. |
1769 | to the small absolute number of watchers (that is, you need efficiency and |
|
|
1770 | speed most when you have lots of watchers, not when you only have a few of |
|
|
1771 | them). |
1129 | |
1772 | |
1130 | EV is again fastest. |
1773 | EV is again fastest. |
1131 | |
1774 | |
1132 | The C-based event loops Event and Glib come in second this time, as the |
1775 | Perl again comes second. It is noticeably faster than the C-based event |
1133 | overhead of running an iteration is much smaller in C than in Perl (little |
1776 | loops Event and Glib, although the difference is too small to really |
1134 | code to execute in the inner loop, and perl's function calling overhead is |
1777 | matter. |
1135 | high, and updating all the data structures is costly). |
|
|
1136 | |
1778 | |
1137 | The pure perl event loop is much slower, but still competitive. |
|
|
1138 | |
|
|
1139 | POE also performs much better in this case, but is is stillf ar behind the |
1779 | POE also performs much better in this case, but is is still far behind the |
1140 | others. |
1780 | others. |
1141 | |
1781 | |
1142 | =head3 Summary |
1782 | =head3 Summary |
1143 | |
1783 | |
1144 | =over 4 |
1784 | =over 4 |
… | |
… | |
1147 | watchers, as the management overhead dominates. |
1787 | watchers, as the management overhead dominates. |
1148 | |
1788 | |
1149 | =back |
1789 | =back |
1150 | |
1790 | |
1151 | |
1791 | |
|
|
1792 | =head1 SIGNALS |
|
|
1793 | |
|
|
1794 | AnyEvent currently installs handlers for these signals: |
|
|
1795 | |
|
|
1796 | =over 4 |
|
|
1797 | |
|
|
1798 | =item SIGCHLD |
|
|
1799 | |
|
|
1800 | A handler for C<SIGCHLD> is installed by AnyEvent's child watcher |
|
|
1801 | emulation for event loops that do not support them natively. Also, some |
|
|
1802 | event loops install a similar handler. |
|
|
1803 | |
|
|
1804 | =item SIGPIPE |
|
|
1805 | |
|
|
1806 | A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> |
|
|
1807 | when AnyEvent gets loaded. |
|
|
1808 | |
|
|
1809 | The rationale for this is that AnyEvent users usually do not really depend |
|
|
1810 | on SIGPIPE delivery (which is purely an optimisation for shell use, or |
|
|
1811 | badly-written programs), but C<SIGPIPE> can cause spurious and rare |
|
|
1812 | program exits as a lot of people do not expect C<SIGPIPE> when writing to |
|
|
1813 | some random socket. |
|
|
1814 | |
|
|
1815 | The rationale for installing a no-op handler as opposed to ignoring it is |
|
|
1816 | that this way, the handler will be restored to defaults on exec. |
|
|
1817 | |
|
|
1818 | Feel free to install your own handler, or reset it to defaults. |
|
|
1819 | |
|
|
1820 | =back |
|
|
1821 | |
|
|
1822 | =cut |
|
|
1823 | |
|
|
1824 | $SIG{PIPE} = sub { } |
|
|
1825 | unless defined $SIG{PIPE}; |
|
|
1826 | |
|
|
1827 | |
1152 | =head1 FORK |
1828 | =head1 FORK |
1153 | |
1829 | |
1154 | Most event libraries are not fork-safe. The ones who are usually are |
1830 | Most event libraries are not fork-safe. The ones who are usually are |
1155 | because they are so inefficient. Only L<EV> is fully fork-aware. |
1831 | because they rely on inefficient but fork-safe C<select> or C<poll> |
|
|
1832 | calls. Only L<EV> is fully fork-aware. |
1156 | |
1833 | |
1157 | If you have to fork, you must either do so I<before> creating your first |
1834 | If you have to fork, you must either do so I<before> creating your first |
1158 | watcher OR you must not use AnyEvent at all in the child. |
1835 | watcher OR you must not use AnyEvent at all in the child. |
1159 | |
1836 | |
1160 | |
1837 | |
… | |
… | |
1168 | specified in the variable. |
1845 | specified in the variable. |
1169 | |
1846 | |
1170 | You can make AnyEvent completely ignore this variable by deleting it |
1847 | You can make AnyEvent completely ignore this variable by deleting it |
1171 | before the first watcher gets created, e.g. with a C<BEGIN> block: |
1848 | before the first watcher gets created, e.g. with a C<BEGIN> block: |
1172 | |
1849 | |
1173 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
1850 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
1174 | |
1851 | |
1175 | use AnyEvent; |
1852 | use AnyEvent; |
|
|
1853 | |
|
|
1854 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
|
|
1855 | be used to probe what backend is used and gain other information (which is |
|
|
1856 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and |
|
|
1857 | $ENV{PERL_ANYEGENT_STRICT}. |
|
|
1858 | |
|
|
1859 | |
|
|
1860 | =head1 BUGS |
|
|
1861 | |
|
|
1862 | Perl 5.8 has numerous memleaks that sometimes hit this module and are hard |
|
|
1863 | to work around. If you suffer from memleaks, first upgrade to Perl 5.10 |
|
|
1864 | and check wether the leaks still show up. (Perl 5.10.0 has other annoying |
|
|
1865 | memleaks, such as leaking on C<map> and C<grep> but it is usually not as |
|
|
1866 | pronounced). |
1176 | |
1867 | |
1177 | |
1868 | |
1178 | =head1 SEE ALSO |
1869 | =head1 SEE ALSO |
1179 | |
1870 | |
1180 | Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>, |
1871 | Utility functions: L<AnyEvent::Util>. |
1181 | L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>, |
1872 | |
|
|
1873 | Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, |
1182 | L<Event::Lib>, L<Qt>, L<POE>. |
1874 | L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. |
1183 | |
1875 | |
1184 | Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>, |
1876 | Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, |
1185 | L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, |
1877 | L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, |
1186 | L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>, |
1878 | L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, |
1187 | L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>. |
1879 | L<AnyEvent::Impl::POE>. |
1188 | |
1880 | |
|
|
1881 | Non-blocking file handles, sockets, TCP clients and |
|
|
1882 | servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. |
|
|
1883 | |
|
|
1884 | Asynchronous DNS: L<AnyEvent::DNS>. |
|
|
1885 | |
|
|
1886 | Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, |
|
|
1887 | |
1189 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. |
1888 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. |
1190 | |
1889 | |
1191 | |
1890 | |
1192 | =head1 AUTHOR |
1891 | =head1 AUTHOR |
1193 | |
1892 | |
1194 | Marc Lehmann <schmorp@schmorp.de> |
1893 | Marc Lehmann <schmorp@schmorp.de> |
1195 | http://home.schmorp.de/ |
1894 | http://home.schmorp.de/ |
1196 | |
1895 | |
1197 | =cut |
1896 | =cut |
1198 | |
1897 | |
1199 | 1 |
1898 | 1 |
1200 | |
1899 | |