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 and POE are various supported |
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6 | event loops. |
6 | |
7 | |
7 | =head1 SYNOPSIS |
8 | =head1 SYNOPSIS |
8 | |
9 | |
9 | use AnyEvent; |
10 | use AnyEvent; |
10 | |
11 | |
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12 | # file descriptor readable |
11 | my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { |
13 | my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... }); |
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14 | |
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15 | # one-shot or repeating timers |
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16 | my $w = AnyEvent->timer (after => $seconds, cb => sub { ... }); |
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17 | my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ... |
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18 | |
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19 | print AnyEvent->now; # prints current event loop time |
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20 | print AnyEvent->time; # think Time::HiRes::time or simply CORE::time. |
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21 | |
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22 | # POSIX signal |
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23 | my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... }); |
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24 | |
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25 | # child process exit |
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26 | my $w = AnyEvent->child (pid => $pid, cb => sub { |
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27 | my ($pid, $status) = @_; |
12 | ... |
28 | ... |
13 | }); |
29 | }); |
14 | |
30 | |
15 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
31 | # called when event loop idle (if applicable) |
16 | ... |
32 | my $w = AnyEvent->idle (cb => sub { ... }); |
17 | }); |
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18 | |
33 | |
19 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
34 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
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35 | $w->send; # wake up current and all future recv's |
20 | $w->wait; # enters "main loop" till $condvar gets ->send |
36 | $w->recv; # enters "main loop" till $condvar gets ->send |
21 | $w->send; # wake up current and all future wait's |
37 | # use a condvar in callback mode: |
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38 | $w->cb (sub { $_[0]->recv }); |
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39 | |
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40 | =head1 INTRODUCTION/TUTORIAL |
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41 | |
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42 | This manpage is mainly a reference manual. If you are interested |
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43 | in a tutorial or some gentle introduction, have a look at the |
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44 | L<AnyEvent::Intro> manpage. |
22 | |
45 | |
23 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
46 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
24 | |
47 | |
25 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
48 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
26 | nowadays. So what is different about AnyEvent? |
49 | nowadays. So what is different about AnyEvent? |
27 | |
50 | |
28 | Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of |
51 | Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of |
29 | policy> and AnyEvent is I<small and efficient>. |
52 | policy> and AnyEvent is I<small and efficient>. |
30 | |
53 | |
31 | First and foremost, I<AnyEvent is not an event model> itself, it only |
54 | 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 |
55 | 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, |
56 | 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, |
57 | 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 |
58 | only one event loop can be active at the same time in a process. AnyEvent |
36 | helps hiding the differences between those event loops. |
59 | cannot change this, but it can hide the differences between those event |
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60 | loops. |
37 | |
61 | |
38 | The goal of AnyEvent is to offer module authors the ability to do event |
62 | 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 |
63 | programming (waiting for I/O or timer events) without subscribing to a |
40 | religion, a way of living, and most importantly: without forcing your |
64 | 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 |
65 | module users into the same thing by forcing them to use the same event |
42 | model you use. |
66 | model you use. |
43 | |
67 | |
44 | For modules like POE or IO::Async (which is a total misnomer as it is |
68 | 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 |
69 | 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 |
70 | 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 |
71 | 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 |
72 | 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. |
73 | module are I<also> forced to use the same event loop you use. |
50 | |
74 | |
51 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
75 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
52 | fine. AnyEvent + Tk works fine etc. etc. but none of these work together |
76 | 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 |
77 | 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, |
78 | 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 |
79 | 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 |
80 | 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 |
81 | 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). |
82 | to AnyEvent, too, so it is future-proof). |
59 | |
83 | |
60 | In addition to being free of having to use I<the one and only true event |
84 | 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 |
85 | 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 |
86 | 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 |
87 | 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 |
88 | offering the functionality that is necessary, in as thin as a wrapper as |
65 | technically possible. |
89 | technically possible. |
66 | |
90 | |
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91 | Of course, AnyEvent comes with a big (and fully optional!) toolbox |
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92 | of useful functionality, such as an asynchronous DNS resolver, 100% |
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93 | non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms |
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94 | such as Windows) and lots of real-world knowledge and workarounds for |
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95 | platform bugs and differences. |
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96 | |
67 | Of course, if you want lots of policy (this can arguably be somewhat |
97 | 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 |
98 | useful) and you want to force your users to use the one and only event |
69 | model, you should I<not> use this module. |
99 | model, you should I<not> use this module. |
70 | |
100 | |
71 | =head1 DESCRIPTION |
101 | =head1 DESCRIPTION |
72 | |
102 | |
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78 | The interface itself is vaguely similar, but not identical to the L<Event> |
108 | The interface itself is vaguely similar, but not identical to the L<Event> |
79 | module. |
109 | module. |
80 | |
110 | |
81 | During the first call of any watcher-creation method, the module tries |
111 | During the first call of any watcher-creation method, the module tries |
82 | to detect the currently loaded event loop by probing whether one of the |
112 | to detect the currently loaded event loop by probing whether one of the |
83 | following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>, |
113 | following modules is already loaded: L<EV>, |
84 | L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, |
114 | L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, |
85 | L<POE>. The first one found is used. If none are found, the module tries |
115 | L<POE>. The first one found is used. If none are found, the module tries |
86 | to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl |
116 | to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl |
87 | adaptor should always succeed) in the order given. The first one that can |
117 | adaptor should always succeed) in the order given. The first one that can |
88 | be successfully loaded will be used. If, after this, still none could be |
118 | be successfully loaded will be used. If, after this, still none could be |
… | |
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102 | starts using it, all bets are off. Maybe you should tell their authors to |
132 | starts using it, all bets are off. Maybe you should tell their authors to |
103 | use AnyEvent so their modules work together with others seamlessly... |
133 | use AnyEvent so their modules work together with others seamlessly... |
104 | |
134 | |
105 | The pure-perl implementation of AnyEvent is called |
135 | The pure-perl implementation of AnyEvent is called |
106 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
136 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
107 | explicitly. |
137 | explicitly and enjoy the high availability of that event loop :) |
108 | |
138 | |
109 | =head1 WATCHERS |
139 | =head1 WATCHERS |
110 | |
140 | |
111 | AnyEvent has the central concept of a I<watcher>, which is an object that |
141 | AnyEvent has the central concept of a I<watcher>, which is an object that |
112 | stores relevant data for each kind of event you are waiting for, such as |
142 | stores relevant data for each kind of event you are waiting for, such as |
113 | the callback to call, the filehandle to watch, etc. |
143 | the callback to call, the file handle to watch, etc. |
114 | |
144 | |
115 | These watchers are normal Perl objects with normal Perl lifetime. After |
145 | These watchers are normal Perl objects with normal Perl lifetime. After |
116 | creating a watcher it will immediately "watch" for events and invoke the |
146 | creating a watcher it will immediately "watch" for events and invoke the |
117 | callback when the event occurs (of course, only when the event model |
147 | callback when the event occurs (of course, only when the event model |
118 | is in control). |
148 | is in control). |
119 | |
149 | |
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150 | Note that B<callbacks must not permanently change global variables> |
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151 | potentially in use by the event loop (such as C<$_> or C<$[>) and that B<< |
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152 | callbacks must not C<die> >>. The former is good programming practise in |
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153 | Perl and the latter stems from the fact that exception handling differs |
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154 | widely between event loops. |
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155 | |
120 | To disable the watcher you have to destroy it (e.g. by setting the |
156 | To disable the watcher you have to destroy it (e.g. by setting the |
121 | variable you store it in to C<undef> or otherwise deleting all references |
157 | variable you store it in to C<undef> or otherwise deleting all references |
122 | to it). |
158 | to it). |
123 | |
159 | |
124 | All watchers are created by calling a method on the C<AnyEvent> class. |
160 | All watchers are created by calling a method on the C<AnyEvent> class. |
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126 | Many watchers either are used with "recursion" (repeating timers for |
162 | Many watchers either are used with "recursion" (repeating timers for |
127 | example), or need to refer to their watcher object in other ways. |
163 | example), or need to refer to their watcher object in other ways. |
128 | |
164 | |
129 | An any way to achieve that is this pattern: |
165 | An any way to achieve that is this pattern: |
130 | |
166 | |
131 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
167 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
132 | # you can use $w here, for example to undef it |
168 | # you can use $w here, for example to undef it |
133 | undef $w; |
169 | undef $w; |
134 | }); |
170 | }); |
135 | |
171 | |
136 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
172 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
137 | my variables are only visible after the statement in which they are |
173 | my variables are only visible after the statement in which they are |
138 | declared. |
174 | declared. |
139 | |
175 | |
140 | =head2 I/O WATCHERS |
176 | =head2 I/O WATCHERS |
141 | |
177 | |
142 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
178 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
143 | with the following mandatory key-value pairs as arguments: |
179 | with the following mandatory key-value pairs as arguments: |
144 | |
180 | |
145 | C<fh> the Perl I<file handle> (I<not> file descriptor) to watch |
181 | C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch |
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182 | for events (AnyEvent might or might not keep a reference to this file |
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183 | handle). Note that only file handles pointing to things for which |
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184 | non-blocking operation makes sense are allowed. This includes sockets, |
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185 | most character devices, pipes, fifos and so on, but not for example files |
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186 | or block devices. |
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187 | |
146 | for events. C<poll> must be a string that is either C<r> or C<w>, |
188 | C<poll> must be a string that is either C<r> or C<w>, which creates a |
147 | which creates a watcher waiting for "r"eadable or "w"ritable events, |
189 | watcher waiting for "r"eadable or "w"ritable events, respectively. |
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190 | |
148 | respectively. C<cb> is the callback to invoke each time the file handle |
191 | C<cb> is the callback to invoke each time the file handle becomes ready. |
149 | becomes ready. |
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150 | |
192 | |
151 | Although the callback might get passed parameters, their value and |
193 | Although the callback might get passed parameters, their value and |
152 | presence is undefined and you cannot rely on them. Portable AnyEvent |
194 | presence is undefined and you cannot rely on them. Portable AnyEvent |
153 | callbacks cannot use arguments passed to I/O watcher callbacks. |
195 | callbacks cannot use arguments passed to I/O watcher callbacks. |
154 | |
196 | |
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158 | |
200 | |
159 | Some event loops issue spurious readyness notifications, so you should |
201 | Some event loops issue spurious readyness notifications, so you should |
160 | always use non-blocking calls when reading/writing from/to your file |
202 | always use non-blocking calls when reading/writing from/to your file |
161 | handles. |
203 | handles. |
162 | |
204 | |
163 | Example: |
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164 | |
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165 | # wait for readability of STDIN, then read a line and disable the watcher |
205 | Example: wait for readability of STDIN, then read a line and disable the |
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206 | watcher. |
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207 | |
166 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
208 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
167 | chomp (my $input = <STDIN>); |
209 | chomp (my $input = <STDIN>); |
168 | warn "read: $input\n"; |
210 | warn "read: $input\n"; |
169 | undef $w; |
211 | undef $w; |
170 | }); |
212 | }); |
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180 | |
222 | |
181 | Although the callback might get passed parameters, their value and |
223 | Although the callback might get passed parameters, their value and |
182 | presence is undefined and you cannot rely on them. Portable AnyEvent |
224 | presence is undefined and you cannot rely on them. Portable AnyEvent |
183 | callbacks cannot use arguments passed to time watcher callbacks. |
225 | callbacks cannot use arguments passed to time watcher callbacks. |
184 | |
226 | |
185 | The timer callback will be invoked at most once: if you want a repeating |
227 | The callback will normally be invoked once only. If you specify another |
186 | timer you have to create a new watcher (this is a limitation by both Tk |
228 | parameter, C<interval>, as a strictly positive number (> 0), then the |
187 | and Glib). |
229 | callback will be invoked regularly at that interval (in fractional |
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230 | seconds) after the first invocation. If C<interval> is specified with a |
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231 | false value, then it is treated as if it were missing. |
188 | |
232 | |
189 | Example: |
233 | The callback will be rescheduled before invoking the callback, but no |
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234 | attempt is done to avoid timer drift in most backends, so the interval is |
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235 | only approximate. |
190 | |
236 | |
191 | # fire an event after 7.7 seconds |
237 | Example: fire an event after 7.7 seconds. |
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238 | |
192 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
239 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
193 | warn "timeout\n"; |
240 | warn "timeout\n"; |
194 | }); |
241 | }); |
195 | |
242 | |
196 | # to cancel the timer: |
243 | # to cancel the timer: |
197 | undef $w; |
244 | undef $w; |
198 | |
245 | |
199 | Example 2: |
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200 | |
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201 | # fire an event after 0.5 seconds, then roughly every second |
246 | Example 2: fire an event after 0.5 seconds, then roughly every second. |
202 | my $w; |
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203 | |
247 | |
204 | my $cb = sub { |
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205 | # cancel the old timer while creating a new one |
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206 | $w = AnyEvent->timer (after => 1, cb => $cb); |
248 | my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub { |
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249 | warn "timeout\n"; |
207 | }; |
250 | }; |
208 | |
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209 | # start the "loop" by creating the first watcher |
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210 | $w = AnyEvent->timer (after => 0.5, cb => $cb); |
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211 | |
251 | |
212 | =head3 TIMING ISSUES |
252 | =head3 TIMING ISSUES |
213 | |
253 | |
214 | There are two ways to handle timers: based on real time (relative, "fire |
254 | There are two ways to handle timers: based on real time (relative, "fire |
215 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
255 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
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227 | timers. |
267 | timers. |
228 | |
268 | |
229 | AnyEvent always prefers relative timers, if available, matching the |
269 | AnyEvent always prefers relative timers, if available, matching the |
230 | AnyEvent API. |
270 | AnyEvent API. |
231 | |
271 | |
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272 | AnyEvent has two additional methods that return the "current time": |
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273 | |
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274 | =over 4 |
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275 | |
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276 | =item AnyEvent->time |
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277 | |
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278 | This returns the "current wallclock time" as a fractional number of |
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279 | seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time> |
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280 | return, and the result is guaranteed to be compatible with those). |
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281 | |
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282 | It progresses independently of any event loop processing, i.e. each call |
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283 | will check the system clock, which usually gets updated frequently. |
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284 | |
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285 | =item AnyEvent->now |
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286 | |
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287 | This also returns the "current wallclock time", but unlike C<time>, above, |
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288 | this value might change only once per event loop iteration, depending on |
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289 | the event loop (most return the same time as C<time>, above). This is the |
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290 | time that AnyEvent's timers get scheduled against. |
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291 | |
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292 | I<In almost all cases (in all cases if you don't care), this is the |
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293 | function to call when you want to know the current time.> |
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294 | |
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295 | This function is also often faster then C<< AnyEvent->time >>, and |
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296 | thus the preferred method if you want some timestamp (for example, |
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297 | L<AnyEvent::Handle> uses this to update it's activity timeouts). |
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298 | |
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299 | The rest of this section is only of relevance if you try to be very exact |
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300 | with your timing, you can skip it without bad conscience. |
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301 | |
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302 | For a practical example of when these times differ, consider L<Event::Lib> |
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303 | and L<EV> and the following set-up: |
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304 | |
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305 | The event loop is running and has just invoked one of your callback at |
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306 | time=500 (assume no other callbacks delay processing). In your callback, |
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307 | you wait a second by executing C<sleep 1> (blocking the process for a |
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308 | second) and then (at time=501) you create a relative timer that fires |
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309 | after three seconds. |
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310 | |
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311 | With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will |
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312 | both return C<501>, because that is the current time, and the timer will |
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313 | be scheduled to fire at time=504 (C<501> + C<3>). |
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314 | |
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315 | With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current |
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316 | time), but C<< AnyEvent->now >> returns C<500>, as that is the time the |
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317 | last event processing phase started. With L<EV>, your timer gets scheduled |
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318 | to run at time=503 (C<500> + C<3>). |
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319 | |
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320 | In one sense, L<Event::Lib> is more exact, as it uses the current time |
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321 | regardless of any delays introduced by event processing. However, most |
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322 | callbacks do not expect large delays in processing, so this causes a |
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323 | higher drift (and a lot more system calls to get the current time). |
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324 | |
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325 | In another sense, L<EV> is more exact, as your timer will be scheduled at |
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326 | the same time, regardless of how long event processing actually took. |
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327 | |
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328 | In either case, if you care (and in most cases, you don't), then you |
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329 | can get whatever behaviour you want with any event loop, by taking the |
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330 | difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into |
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331 | account. |
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332 | |
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333 | =item AnyEvent->now_update |
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334 | |
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335 | Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache |
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336 | the current time for each loop iteration (see the discussion of L<< |
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337 | AnyEvent->now >>, above). |
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338 | |
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339 | When a callback runs for a long time (or when the process sleeps), then |
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340 | this "current" time will differ substantially from the real time, which |
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341 | might affect timers and time-outs. |
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342 | |
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343 | When this is the case, you can call this method, which will update the |
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344 | event loop's idea of "current time". |
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345 | |
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346 | Note that updating the time I<might> cause some events to be handled. |
|
|
347 | |
|
|
348 | =back |
|
|
349 | |
232 | =head2 SIGNAL WATCHERS |
350 | =head2 SIGNAL WATCHERS |
233 | |
351 | |
234 | You can watch for signals using a signal watcher, C<signal> is the signal |
352 | You can watch for signals using a signal watcher, C<signal> is the signal |
235 | I<name> without any C<SIG> prefix, C<cb> is the Perl callback to |
353 | I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl |
236 | be invoked whenever a signal occurs. |
354 | callback to be invoked whenever a signal occurs. |
237 | |
355 | |
238 | Although the callback might get passed parameters, their value and |
356 | Although the callback might get passed parameters, their value and |
239 | presence is undefined and you cannot rely on them. Portable AnyEvent |
357 | presence is undefined and you cannot rely on them. Portable AnyEvent |
240 | callbacks cannot use arguments passed to signal watcher callbacks. |
358 | callbacks cannot use arguments passed to signal watcher callbacks. |
241 | |
359 | |
242 | Multiple signal occurances can be clumped together into one callback |
360 | Multiple signal occurrences can be clumped together into one callback |
243 | invocation, and callback invocation will be synchronous. synchronous means |
361 | invocation, and callback invocation will be synchronous. Synchronous means |
244 | that it might take a while until the signal gets handled by the process, |
362 | that it might take a while until the signal gets handled by the process, |
245 | but it is guarenteed not to interrupt any other callbacks. |
363 | but it is guaranteed not to interrupt any other callbacks. |
246 | |
364 | |
247 | The main advantage of using these watchers is that you can share a signal |
365 | The main advantage of using these watchers is that you can share a signal |
248 | between multiple watchers. |
366 | between multiple watchers. |
249 | |
367 | |
250 | This watcher might use C<%SIG>, so programs overwriting those signals |
368 | This watcher might use C<%SIG>, so programs overwriting those signals |
… | |
… | |
257 | =head2 CHILD PROCESS WATCHERS |
375 | =head2 CHILD PROCESS WATCHERS |
258 | |
376 | |
259 | You can also watch on a child process exit and catch its exit status. |
377 | You can also watch on a child process exit and catch its exit status. |
260 | |
378 | |
261 | The child process is specified by the C<pid> argument (if set to C<0>, it |
379 | The child process is specified by the C<pid> argument (if set to C<0>, it |
262 | watches for any child process exit). The watcher will trigger as often |
380 | watches for any child process exit). The watcher will triggered only when |
263 | as status change for the child are received. This works by installing a |
381 | the child process has finished and an exit status is available, not on |
264 | signal handler for C<SIGCHLD>. The callback will be called with the pid |
382 | any trace events (stopped/continued). |
265 | and exit status (as returned by waitpid), so unlike other watcher types, |
383 | |
266 | you I<can> rely on child watcher callback arguments. |
384 | The callback will be called with the pid and exit status (as returned by |
|
|
385 | waitpid), so unlike other watcher types, you I<can> rely on child watcher |
|
|
386 | callback arguments. |
|
|
387 | |
|
|
388 | This watcher type works by installing a signal handler for C<SIGCHLD>, |
|
|
389 | and since it cannot be shared, nothing else should use SIGCHLD or reap |
|
|
390 | random child processes (waiting for specific child processes, e.g. inside |
|
|
391 | C<system>, is just fine). |
267 | |
392 | |
268 | There is a slight catch to child watchers, however: you usually start them |
393 | There is a slight catch to child watchers, however: you usually start them |
269 | I<after> the child process was created, and this means the process could |
394 | I<after> the child process was created, and this means the process could |
270 | have exited already (and no SIGCHLD will be sent anymore). |
395 | have exited already (and no SIGCHLD will be sent anymore). |
271 | |
396 | |
… | |
… | |
277 | AnyEvent program, you I<have> to create at least one watcher before you |
402 | AnyEvent program, you I<have> to create at least one watcher before you |
278 | C<fork> the child (alternatively, you can call C<AnyEvent::detect>). |
403 | C<fork> the child (alternatively, you can call C<AnyEvent::detect>). |
279 | |
404 | |
280 | Example: fork a process and wait for it |
405 | Example: fork a process and wait for it |
281 | |
406 | |
282 | my $done = AnyEvent->condvar; |
407 | my $done = AnyEvent->condvar; |
283 | |
408 | |
284 | AnyEvent::detect; # force event module to be initialised |
|
|
285 | |
|
|
286 | my $pid = fork or exit 5; |
409 | my $pid = fork or exit 5; |
287 | |
410 | |
288 | my $w = AnyEvent->child ( |
411 | my $w = AnyEvent->child ( |
289 | pid => $pid, |
412 | pid => $pid, |
290 | cb => sub { |
413 | cb => sub { |
291 | my ($pid, $status) = @_; |
414 | my ($pid, $status) = @_; |
292 | warn "pid $pid exited with status $status"; |
415 | warn "pid $pid exited with status $status"; |
293 | $done->send; |
416 | $done->send; |
294 | }, |
417 | }, |
295 | ); |
418 | ); |
296 | |
419 | |
297 | # do something else, then wait for process exit |
420 | # do something else, then wait for process exit |
298 | $done->wait; |
421 | $done->recv; |
|
|
422 | |
|
|
423 | =head2 IDLE WATCHERS |
|
|
424 | |
|
|
425 | Sometimes there is a need to do something, but it is not so important |
|
|
426 | to do it instantly, but only when there is nothing better to do. This |
|
|
427 | "nothing better to do" is usually defined to be "no other events need |
|
|
428 | attention by the event loop". |
|
|
429 | |
|
|
430 | Idle watchers ideally get invoked when the event loop has nothing |
|
|
431 | better to do, just before it would block the process to wait for new |
|
|
432 | events. Instead of blocking, the idle watcher is invoked. |
|
|
433 | |
|
|
434 | Most event loops unfortunately do not really support idle watchers (only |
|
|
435 | EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent |
|
|
436 | will simply call the callback "from time to time". |
|
|
437 | |
|
|
438 | Example: read lines from STDIN, but only process them when the |
|
|
439 | program is otherwise idle: |
|
|
440 | |
|
|
441 | my @lines; # read data |
|
|
442 | my $idle_w; |
|
|
443 | my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
|
|
444 | push @lines, scalar <STDIN>; |
|
|
445 | |
|
|
446 | # start an idle watcher, if not already done |
|
|
447 | $idle_w ||= AnyEvent->idle (cb => sub { |
|
|
448 | # handle only one line, when there are lines left |
|
|
449 | if (my $line = shift @lines) { |
|
|
450 | print "handled when idle: $line"; |
|
|
451 | } else { |
|
|
452 | # otherwise disable the idle watcher again |
|
|
453 | undef $idle_w; |
|
|
454 | } |
|
|
455 | }); |
|
|
456 | }); |
299 | |
457 | |
300 | =head2 CONDITION VARIABLES |
458 | =head2 CONDITION VARIABLES |
301 | |
459 | |
302 | If you are familiar with some event loops you will know that all of them |
460 | If you are familiar with some event loops you will know that all of them |
303 | require you to run some blocking "loop", "run" or similar function that |
461 | require you to run some blocking "loop", "run" or similar function that |
… | |
… | |
309 | The instrument to do that is called a "condition variable", so called |
467 | The instrument to do that is called a "condition variable", so called |
310 | because they represent a condition that must become true. |
468 | because they represent a condition that must become true. |
311 | |
469 | |
312 | Condition variables can be created by calling the C<< AnyEvent->condvar |
470 | Condition variables can be created by calling the C<< AnyEvent->condvar |
313 | >> method, usually without arguments. The only argument pair allowed is |
471 | >> method, usually without arguments. The only argument pair allowed is |
|
|
472 | |
314 | C<cb>, which specifies a callback to be called when the condition variable |
473 | C<cb>, which specifies a callback to be called when the condition variable |
315 | becomes true. |
474 | becomes true, with the condition variable as the first argument (but not |
|
|
475 | the results). |
316 | |
476 | |
317 | After creation, the conditon variable is "false" until it becomes "true" |
477 | After creation, the condition variable is "false" until it becomes "true" |
318 | by calling the C<send> method. |
478 | by calling the C<send> method (or calling the condition variable as if it |
|
|
479 | were a callback, read about the caveats in the description for the C<< |
|
|
480 | ->send >> method). |
319 | |
481 | |
320 | Condition variables are similar to callbacks, except that you can |
482 | Condition variables are similar to callbacks, except that you can |
321 | optionally wait for them. They can also be called merge points - points |
483 | optionally wait for them. They can also be called merge points - points |
322 | in time where multiple outstandign events have been processed. And yet |
484 | in time where multiple outstanding events have been processed. And yet |
323 | another way to call them is transations - each condition variable can be |
485 | another way to call them is transactions - each condition variable can be |
324 | used to represent a transaction, which finishes at some point and delivers |
486 | used to represent a transaction, which finishes at some point and delivers |
325 | a result. |
487 | a result. |
326 | |
488 | |
327 | Condition variables are very useful to signal that something has finished, |
489 | Condition variables are very useful to signal that something has finished, |
328 | for example, if you write a module that does asynchronous http requests, |
490 | for example, if you write a module that does asynchronous http requests, |
329 | then a condition variable would be the ideal candidate to signal the |
491 | then a condition variable would be the ideal candidate to signal the |
330 | availability of results. The user can either act when the callback is |
492 | availability of results. The user can either act when the callback is |
331 | called or can synchronously C<< ->wait >> for the results. |
493 | called or can synchronously C<< ->recv >> for the results. |
332 | |
494 | |
333 | You can also use them to simulate traditional event loops - for example, |
495 | You can also use them to simulate traditional event loops - for example, |
334 | you can block your main program until an event occurs - for example, you |
496 | you can block your main program until an event occurs - for example, you |
335 | could C<< ->wait >> in your main program until the user clicks the Quit |
497 | could C<< ->recv >> in your main program until the user clicks the Quit |
336 | button of your app, which would C<< ->send >> the "quit" event. |
498 | button of your app, which would C<< ->send >> the "quit" event. |
337 | |
499 | |
338 | Note that condition variables recurse into the event loop - if you have |
500 | Note that condition variables recurse into the event loop - if you have |
339 | two pieces of code that call C<< ->wait >> in a round-robbin fashion, you |
501 | two pieces of code that call C<< ->recv >> in a round-robin fashion, you |
340 | lose. Therefore, condition variables are good to export to your caller, but |
502 | lose. Therefore, condition variables are good to export to your caller, but |
341 | you should avoid making a blocking wait yourself, at least in callbacks, |
503 | you should avoid making a blocking wait yourself, at least in callbacks, |
342 | as this asks for trouble. |
504 | as this asks for trouble. |
343 | |
505 | |
344 | Condition variables are represented by hash refs in perl, and the keys |
506 | Condition variables are represented by hash refs in perl, and the keys |
… | |
… | |
349 | |
511 | |
350 | There are two "sides" to a condition variable - the "producer side" which |
512 | There are two "sides" to a condition variable - the "producer side" which |
351 | eventually calls C<< -> send >>, and the "consumer side", which waits |
513 | eventually calls C<< -> send >>, and the "consumer side", which waits |
352 | for the send to occur. |
514 | for the send to occur. |
353 | |
515 | |
354 | Example: |
516 | Example: wait for a timer. |
355 | |
517 | |
356 | # wait till the result is ready |
518 | # wait till the result is ready |
357 | my $result_ready = AnyEvent->condvar; |
519 | my $result_ready = AnyEvent->condvar; |
358 | |
520 | |
359 | # do something such as adding a timer |
521 | # do something such as adding a timer |
… | |
… | |
365 | cb => sub { $result_ready->send }, |
527 | cb => sub { $result_ready->send }, |
366 | ); |
528 | ); |
367 | |
529 | |
368 | # this "blocks" (while handling events) till the callback |
530 | # this "blocks" (while handling events) till the callback |
369 | # calls send |
531 | # calls send |
370 | $result_ready->wait; |
532 | $result_ready->recv; |
|
|
533 | |
|
|
534 | Example: wait for a timer, but take advantage of the fact that |
|
|
535 | condition variables are also code references. |
|
|
536 | |
|
|
537 | my $done = AnyEvent->condvar; |
|
|
538 | my $delay = AnyEvent->timer (after => 5, cb => $done); |
|
|
539 | $done->recv; |
|
|
540 | |
|
|
541 | Example: Imagine an API that returns a condvar and doesn't support |
|
|
542 | callbacks. This is how you make a synchronous call, for example from |
|
|
543 | the main program: |
|
|
544 | |
|
|
545 | use AnyEvent::CouchDB; |
|
|
546 | |
|
|
547 | ... |
|
|
548 | |
|
|
549 | my @info = $couchdb->info->recv; |
|
|
550 | |
|
|
551 | And this is how you would just ste a callback to be called whenever the |
|
|
552 | results are available: |
|
|
553 | |
|
|
554 | $couchdb->info->cb (sub { |
|
|
555 | my @info = $_[0]->recv; |
|
|
556 | }); |
371 | |
557 | |
372 | =head3 METHODS FOR PRODUCERS |
558 | =head3 METHODS FOR PRODUCERS |
373 | |
559 | |
374 | These methods should only be used by the producing side, i.e. the |
560 | These methods should only be used by the producing side, i.e. the |
375 | code/module that eventually sends the signal. Note that it is also |
561 | code/module that eventually sends the signal. Note that it is also |
… | |
… | |
378 | |
564 | |
379 | =over 4 |
565 | =over 4 |
380 | |
566 | |
381 | =item $cv->send (...) |
567 | =item $cv->send (...) |
382 | |
568 | |
383 | Flag the condition as ready - a running C<< ->wait >> and all further |
569 | Flag the condition as ready - a running C<< ->recv >> and all further |
384 | calls to C<wait> will (eventually) return after this method has been |
570 | calls to C<recv> will (eventually) return after this method has been |
385 | called. If nobody is waiting the send will be remembered. |
571 | called. If nobody is waiting the send will be remembered. |
386 | |
572 | |
387 | If a callback has been set on the condition variable, it is called |
573 | If a callback has been set on the condition variable, it is called |
388 | immediately from within send. |
574 | immediately from within send. |
389 | |
575 | |
390 | Any arguments passed to the C<send> call will be returned by all |
576 | Any arguments passed to the C<send> call will be returned by all |
391 | future C<< ->wait >> calls. |
577 | future C<< ->recv >> calls. |
|
|
578 | |
|
|
579 | Condition variables are overloaded so one can call them directly |
|
|
580 | (as a code reference). Calling them directly is the same as calling |
|
|
581 | C<send>. Note, however, that many C-based event loops do not handle |
|
|
582 | overloading, so as tempting as it may be, passing a condition variable |
|
|
583 | instead of a callback does not work. Both the pure perl and EV loops |
|
|
584 | support overloading, however, as well as all functions that use perl to |
|
|
585 | invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for |
|
|
586 | example). |
392 | |
587 | |
393 | =item $cv->croak ($error) |
588 | =item $cv->croak ($error) |
394 | |
589 | |
395 | Similar to send, but causes all call's wait C<< ->wait >> to invoke |
590 | Similar to send, but causes all call's to C<< ->recv >> to invoke |
396 | C<Carp::croak> with the given error message/object/scalar. |
591 | C<Carp::croak> with the given error message/object/scalar. |
397 | |
592 | |
398 | This can be used to signal any errors to the condition variable |
593 | This can be used to signal any errors to the condition variable |
399 | user/consumer. |
594 | user/consumer. |
400 | |
595 | |
401 | =item $cv->begin ([group callback]) |
596 | =item $cv->begin ([group callback]) |
402 | |
597 | |
403 | =item $cv->end |
598 | =item $cv->end |
|
|
599 | |
|
|
600 | These two methods are EXPERIMENTAL and MIGHT CHANGE. |
404 | |
601 | |
405 | These two methods can be used to combine many transactions/events into |
602 | These two methods can be used to combine many transactions/events into |
406 | one. For example, a function that pings many hosts in parallel might want |
603 | one. For example, a function that pings many hosts in parallel might want |
407 | to use a condition variable for the whole process. |
604 | to use a condition variable for the whole process. |
408 | |
605 | |
… | |
… | |
443 | doesn't execute once). |
640 | doesn't execute once). |
444 | |
641 | |
445 | This is the general pattern when you "fan out" into multiple subrequests: |
642 | This is the general pattern when you "fan out" into multiple subrequests: |
446 | use an outer C<begin>/C<end> pair to set the callback and ensure C<end> |
643 | use an outer C<begin>/C<end> pair to set the callback and ensure C<end> |
447 | is called at least once, and then, for each subrequest you start, call |
644 | is called at least once, and then, for each subrequest you start, call |
448 | C<begin> and for eahc subrequest you finish, call C<end>. |
645 | C<begin> and for each subrequest you finish, call C<end>. |
449 | |
646 | |
450 | =back |
647 | =back |
451 | |
648 | |
452 | =head3 METHODS FOR CONSUMERS |
649 | =head3 METHODS FOR CONSUMERS |
453 | |
650 | |
454 | These methods should only be used by the consuming side, i.e. the |
651 | These methods should only be used by the consuming side, i.e. the |
455 | code awaits the condition. |
652 | code awaits the condition. |
456 | |
653 | |
457 | =over 4 |
654 | =over 4 |
458 | |
655 | |
459 | =item $cv->wait |
656 | =item $cv->recv |
460 | |
657 | |
461 | Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak |
658 | Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak |
462 | >> methods have been called on c<$cv>, while servicing other watchers |
659 | >> methods have been called on c<$cv>, while servicing other watchers |
463 | normally. |
660 | normally. |
464 | |
661 | |
… | |
… | |
475 | (programs might want to do that to stay interactive), so I<if you are |
672 | (programs might want to do that to stay interactive), so I<if you are |
476 | using this from a module, never require a blocking wait>, but let the |
673 | using this from a module, never require a blocking wait>, but let the |
477 | caller decide whether the call will block or not (for example, by coupling |
674 | caller decide whether the call will block or not (for example, by coupling |
478 | condition variables with some kind of request results and supporting |
675 | condition variables with some kind of request results and supporting |
479 | callbacks so the caller knows that getting the result will not block, |
676 | callbacks so the caller knows that getting the result will not block, |
480 | while still suppporting blocking waits if the caller so desires). |
677 | while still supporting blocking waits if the caller so desires). |
481 | |
678 | |
482 | Another reason I<never> to C<< ->wait >> in a module is that you cannot |
679 | Another reason I<never> to C<< ->recv >> in a module is that you cannot |
483 | sensibly have two C<< ->wait >>'s in parallel, as that would require |
680 | sensibly have two C<< ->recv >>'s in parallel, as that would require |
484 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
681 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
485 | can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and |
682 | can supply. |
486 | L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s |
|
|
487 | from different coroutines, however). |
|
|
488 | |
683 | |
|
|
684 | The L<Coro> module, however, I<can> and I<does> supply coroutines and, in |
|
|
685 | fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe |
|
|
686 | versions and also integrates coroutines into AnyEvent, making blocking |
|
|
687 | C<< ->recv >> calls perfectly safe as long as they are done from another |
|
|
688 | coroutine (one that doesn't run the event loop). |
|
|
689 | |
489 | You can ensure that C<< -wait >> never blocks by setting a callback and |
690 | You can ensure that C<< -recv >> never blocks by setting a callback and |
490 | only calling C<< ->wait >> from within that callback (or at a later |
691 | only calling C<< ->recv >> from within that callback (or at a later |
491 | time). This will work even when the event loop does not support blocking |
692 | time). This will work even when the event loop does not support blocking |
492 | waits otherwise. |
693 | waits otherwise. |
493 | |
694 | |
494 | =item $bool = $cv->ready |
695 | =item $bool = $cv->ready |
495 | |
696 | |
496 | Returns true when the condition is "true", i.e. whether C<send> or |
697 | Returns true when the condition is "true", i.e. whether C<send> or |
497 | C<croak> have been called. |
698 | C<croak> have been called. |
498 | |
699 | |
499 | =item $cb = $cv->cb ([new callback]) |
700 | =item $cb = $cv->cb ($cb->($cv)) |
500 | |
701 | |
501 | This is a mutator function that returns the callback set and optionally |
702 | This is a mutator function that returns the callback set and optionally |
502 | replaces it before doing so. |
703 | replaces it before doing so. |
503 | |
704 | |
504 | The callback will be called when the condition becomes "true", i.e. when |
705 | The callback will be called when the condition becomes "true", i.e. when |
505 | C<send> or C<croak> are called. Calling C<wait> inside the callback |
706 | C<send> or C<croak> are called, with the only argument being the condition |
506 | or at any later time is guaranteed not to block. |
707 | variable itself. Calling C<recv> inside the callback or at any later time |
|
|
708 | is guaranteed not to block. |
507 | |
709 | |
508 | =back |
710 | =back |
509 | |
711 | |
510 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
712 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
511 | |
713 | |
… | |
… | |
519 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
721 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
520 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
722 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
521 | |
723 | |
522 | The known classes so far are: |
724 | The known classes so far are: |
523 | |
725 | |
524 | AnyEvent::Impl::CoroEV based on Coro::EV, best choice. |
|
|
525 | AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice. |
|
|
526 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
726 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
527 | AnyEvent::Impl::Event based on Event, second best choice. |
727 | AnyEvent::Impl::Event based on Event, second best choice. |
528 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
728 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
529 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
729 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
530 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
730 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
… | |
… | |
547 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
747 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
548 | if necessary. You should only call this function right before you would |
748 | if necessary. You should only call this function right before you would |
549 | have created an AnyEvent watcher anyway, that is, as late as possible at |
749 | have created an AnyEvent watcher anyway, that is, as late as possible at |
550 | runtime. |
750 | runtime. |
551 | |
751 | |
|
|
752 | =item $guard = AnyEvent::post_detect { BLOCK } |
|
|
753 | |
|
|
754 | Arranges for the code block to be executed as soon as the event model is |
|
|
755 | autodetected (or immediately if this has already happened). |
|
|
756 | |
|
|
757 | If called in scalar or list context, then it creates and returns an object |
|
|
758 | that automatically removes the callback again when it is destroyed. See |
|
|
759 | L<Coro::BDB> for a case where this is useful. |
|
|
760 | |
|
|
761 | =item @AnyEvent::post_detect |
|
|
762 | |
|
|
763 | If there are any code references in this array (you can C<push> to it |
|
|
764 | before or after loading AnyEvent), then they will called directly after |
|
|
765 | the event loop has been chosen. |
|
|
766 | |
|
|
767 | You should check C<$AnyEvent::MODEL> before adding to this array, though: |
|
|
768 | if it contains a true value then the event loop has already been detected, |
|
|
769 | and the array will be ignored. |
|
|
770 | |
|
|
771 | Best use C<AnyEvent::post_detect { BLOCK }> instead. |
|
|
772 | |
552 | =back |
773 | =back |
553 | |
774 | |
554 | =head1 WHAT TO DO IN A MODULE |
775 | =head1 WHAT TO DO IN A MODULE |
555 | |
776 | |
556 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
777 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
… | |
… | |
559 | Be careful when you create watchers in the module body - AnyEvent will |
780 | Be careful when you create watchers in the module body - AnyEvent will |
560 | decide which event module to use as soon as the first method is called, so |
781 | decide which event module to use as soon as the first method is called, so |
561 | by calling AnyEvent in your module body you force the user of your module |
782 | by calling AnyEvent in your module body you force the user of your module |
562 | to load the event module first. |
783 | to load the event module first. |
563 | |
784 | |
564 | Never call C<< ->wait >> on a condition variable unless you I<know> that |
785 | Never call C<< ->recv >> on a condition variable unless you I<know> that |
565 | the C<< ->send >> method has been called on it already. This is |
786 | the C<< ->send >> method has been called on it already. This is |
566 | because it will stall the whole program, and the whole point of using |
787 | because it will stall the whole program, and the whole point of using |
567 | events is to stay interactive. |
788 | events is to stay interactive. |
568 | |
789 | |
569 | It is fine, however, to call C<< ->wait >> when the user of your module |
790 | It is fine, however, to call C<< ->recv >> when the user of your module |
570 | requests it (i.e. if you create a http request object ad have a method |
791 | requests it (i.e. if you create a http request object ad have a method |
571 | called C<results> that returns the results, it should call C<< ->wait >> |
792 | called C<results> that returns the results, it should call C<< ->recv >> |
572 | freely, as the user of your module knows what she is doing. always). |
793 | freely, as the user of your module knows what she is doing. always). |
573 | |
794 | |
574 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
795 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
575 | |
796 | |
576 | There will always be a single main program - the only place that should |
797 | There will always be a single main program - the only place that should |
… | |
… | |
578 | |
799 | |
579 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
800 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
580 | do anything special (it does not need to be event-based) and let AnyEvent |
801 | do anything special (it does not need to be event-based) and let AnyEvent |
581 | decide which implementation to chose if some module relies on it. |
802 | decide which implementation to chose if some module relies on it. |
582 | |
803 | |
583 | If the main program relies on a specific event model. For example, in |
804 | If the main program relies on a specific event model - for example, in |
584 | Gtk2 programs you have to rely on the Glib module. You should load the |
805 | Gtk2 programs you have to rely on the Glib module - you should load the |
585 | event module before loading AnyEvent or any module that uses it: generally |
806 | event module before loading AnyEvent or any module that uses it: generally |
586 | speaking, you should load it as early as possible. The reason is that |
807 | speaking, you should load it as early as possible. The reason is that |
587 | modules might create watchers when they are loaded, and AnyEvent will |
808 | modules might create watchers when they are loaded, and AnyEvent will |
588 | decide on the event model to use as soon as it creates watchers, and it |
809 | decide on the event model to use as soon as it creates watchers, and it |
589 | might chose the wrong one unless you load the correct one yourself. |
810 | might chose the wrong one unless you load the correct one yourself. |
590 | |
811 | |
591 | You can chose to use a rather inefficient pure-perl implementation by |
812 | You can chose to use a pure-perl implementation by loading the |
592 | loading the C<AnyEvent::Impl::Perl> module, which gives you similar |
813 | C<AnyEvent::Impl::Perl> module, which gives you similar behaviour |
593 | behaviour everywhere, but letting AnyEvent chose is generally better. |
814 | everywhere, but letting AnyEvent chose the model is generally better. |
|
|
815 | |
|
|
816 | =head2 MAINLOOP EMULATION |
|
|
817 | |
|
|
818 | Sometimes (often for short test scripts, or even standalone programs who |
|
|
819 | only want to use AnyEvent), you do not want to run a specific event loop. |
|
|
820 | |
|
|
821 | In that case, you can use a condition variable like this: |
|
|
822 | |
|
|
823 | AnyEvent->condvar->recv; |
|
|
824 | |
|
|
825 | This has the effect of entering the event loop and looping forever. |
|
|
826 | |
|
|
827 | Note that usually your program has some exit condition, in which case |
|
|
828 | it is better to use the "traditional" approach of storing a condition |
|
|
829 | variable somewhere, waiting for it, and sending it when the program should |
|
|
830 | exit cleanly. |
|
|
831 | |
594 | |
832 | |
595 | =head1 OTHER MODULES |
833 | =head1 OTHER MODULES |
596 | |
834 | |
597 | The following is a non-exhaustive list of additional modules that use |
835 | The following is a non-exhaustive list of additional modules that use |
598 | AnyEvent and can therefore be mixed easily with other AnyEvent modules |
836 | AnyEvent and can therefore be mixed easily with other AnyEvent modules |
… | |
… | |
604 | =item L<AnyEvent::Util> |
842 | =item L<AnyEvent::Util> |
605 | |
843 | |
606 | Contains various utility functions that replace often-used but blocking |
844 | Contains various utility functions that replace often-used but blocking |
607 | functions such as C<inet_aton> by event-/callback-based versions. |
845 | functions such as C<inet_aton> by event-/callback-based versions. |
608 | |
846 | |
|
|
847 | =item L<AnyEvent::Socket> |
|
|
848 | |
|
|
849 | Provides various utility functions for (internet protocol) sockets, |
|
|
850 | addresses and name resolution. Also functions to create non-blocking tcp |
|
|
851 | connections or tcp servers, with IPv6 and SRV record support and more. |
|
|
852 | |
609 | =item L<AnyEvent::Handle> |
853 | =item L<AnyEvent::Handle> |
610 | |
854 | |
611 | Provide read and write buffers and manages watchers for reads and writes. |
855 | Provide read and write buffers, manages watchers for reads and writes, |
|
|
856 | supports raw and formatted I/O, I/O queued and fully transparent and |
|
|
857 | non-blocking SSL/TLS. |
612 | |
858 | |
613 | =item L<AnyEvent::Socket> |
859 | =item L<AnyEvent::DNS> |
614 | |
860 | |
615 | Provides a means to do non-blocking connects, accepts etc. |
861 | Provides rich asynchronous DNS resolver capabilities. |
|
|
862 | |
|
|
863 | =item L<AnyEvent::HTTP> |
|
|
864 | |
|
|
865 | A simple-to-use HTTP library that is capable of making a lot of concurrent |
|
|
866 | HTTP requests. |
616 | |
867 | |
617 | =item L<AnyEvent::HTTPD> |
868 | =item L<AnyEvent::HTTPD> |
618 | |
869 | |
619 | Provides a simple web application server framework. |
870 | Provides a simple web application server framework. |
620 | |
871 | |
621 | =item L<AnyEvent::DNS> |
|
|
622 | |
|
|
623 | Provides asynchronous DNS resolver capabilities, beyond what |
|
|
624 | L<AnyEvent::Util> offers. |
|
|
625 | |
|
|
626 | =item L<AnyEvent::FastPing> |
872 | =item L<AnyEvent::FastPing> |
627 | |
873 | |
628 | The fastest ping in the west. |
874 | The fastest ping in the west. |
629 | |
875 | |
|
|
876 | =item L<AnyEvent::DBI> |
|
|
877 | |
|
|
878 | Executes L<DBI> requests asynchronously in a proxy process. |
|
|
879 | |
|
|
880 | =item L<AnyEvent::AIO> |
|
|
881 | |
|
|
882 | Truly asynchronous I/O, should be in the toolbox of every event |
|
|
883 | programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent |
|
|
884 | together. |
|
|
885 | |
|
|
886 | =item L<AnyEvent::BDB> |
|
|
887 | |
|
|
888 | Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses |
|
|
889 | L<BDB> and AnyEvent together. |
|
|
890 | |
|
|
891 | =item L<AnyEvent::GPSD> |
|
|
892 | |
|
|
893 | A non-blocking interface to gpsd, a daemon delivering GPS information. |
|
|
894 | |
|
|
895 | =item L<AnyEvent::IGS> |
|
|
896 | |
|
|
897 | A non-blocking interface to the Internet Go Server protocol (used by |
|
|
898 | L<App::IGS>). |
|
|
899 | |
630 | =item L<Net::IRC3> |
900 | =item L<AnyEvent::IRC> |
631 | |
901 | |
632 | AnyEvent based IRC client module family. |
902 | AnyEvent based IRC client module family (replacing the older Net::IRC3). |
633 | |
903 | |
634 | =item L<Net::XMPP2> |
904 | =item L<Net::XMPP2> |
635 | |
905 | |
636 | AnyEvent based XMPP (Jabber protocol) module family. |
906 | AnyEvent based XMPP (Jabber protocol) module family. |
637 | |
907 | |
… | |
… | |
644 | |
914 | |
645 | High level API for event-based execution flow control. |
915 | High level API for event-based execution flow control. |
646 | |
916 | |
647 | =item L<Coro> |
917 | =item L<Coro> |
648 | |
918 | |
649 | Has special support for AnyEvent. |
919 | Has special support for AnyEvent via L<Coro::AnyEvent>. |
650 | |
920 | |
651 | =item L<IO::Lambda> |
921 | =item L<IO::Lambda> |
652 | |
922 | |
653 | The lambda approach to I/O - don't ask, look there. Can use AnyEvent. |
923 | The lambda approach to I/O - don't ask, look there. Can use AnyEvent. |
654 | |
924 | |
655 | =item L<IO::AIO> |
|
|
656 | |
|
|
657 | Truly asynchronous I/O, should be in the toolbox of every event |
|
|
658 | programmer. Can be trivially made to use AnyEvent. |
|
|
659 | |
|
|
660 | =item L<BDB> |
|
|
661 | |
|
|
662 | Truly asynchronous Berkeley DB access. Can be trivially made to use |
|
|
663 | AnyEvent. |
|
|
664 | |
|
|
665 | =back |
925 | =back |
666 | |
926 | |
667 | =cut |
927 | =cut |
668 | |
928 | |
669 | package AnyEvent; |
929 | package AnyEvent; |
670 | |
930 | |
671 | no warnings; |
931 | no warnings; |
672 | use strict; |
932 | use strict qw(vars subs); |
673 | |
933 | |
674 | use Carp; |
934 | use Carp; |
675 | |
935 | |
676 | our $VERSION = '3.3'; |
936 | our $VERSION = 4.411; |
677 | our $MODEL; |
937 | our $MODEL; |
678 | |
938 | |
679 | our $AUTOLOAD; |
939 | our $AUTOLOAD; |
680 | our @ISA; |
940 | our @ISA; |
681 | |
941 | |
|
|
942 | our @REGISTRY; |
|
|
943 | |
|
|
944 | our $WIN32; |
|
|
945 | |
|
|
946 | BEGIN { |
|
|
947 | eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; |
|
|
948 | eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; |
|
|
949 | |
|
|
950 | delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} |
|
|
951 | if ${^TAINT}; |
|
|
952 | } |
|
|
953 | |
682 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
954 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
683 | |
955 | |
684 | our @REGISTRY; |
956 | our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred |
|
|
957 | |
|
|
958 | { |
|
|
959 | my $idx; |
|
|
960 | $PROTOCOL{$_} = ++$idx |
|
|
961 | for reverse split /\s*,\s*/, |
|
|
962 | $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; |
|
|
963 | } |
685 | |
964 | |
686 | my @models = ( |
965 | my @models = ( |
687 | [Coro::EV:: => AnyEvent::Impl::CoroEV::], |
|
|
688 | [Coro::Event:: => AnyEvent::Impl::CoroEvent::], |
|
|
689 | [EV:: => AnyEvent::Impl::EV::], |
966 | [EV:: => AnyEvent::Impl::EV::], |
690 | [Event:: => AnyEvent::Impl::Event::], |
967 | [Event:: => AnyEvent::Impl::Event::], |
691 | [Tk:: => AnyEvent::Impl::Tk::], |
|
|
692 | [Wx:: => AnyEvent::Impl::POE::], |
|
|
693 | [Prima:: => AnyEvent::Impl::POE::], |
|
|
694 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
968 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
695 | # everything below here will not be autoprobed as the pureperl backend should work everywhere |
969 | # everything below here will not be autoprobed |
696 | [Glib:: => AnyEvent::Impl::Glib::], |
970 | # as the pureperl backend should work everywhere |
|
|
971 | # and is usually faster |
|
|
972 | [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles |
|
|
973 | [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers |
697 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
974 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
698 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
975 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
699 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
976 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
|
|
977 | [Wx:: => AnyEvent::Impl::POE::], |
|
|
978 | [Prima:: => AnyEvent::Impl::POE::], |
700 | ); |
979 | ); |
701 | |
980 | |
702 | our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY); |
981 | our %method = map +($_ => 1), |
|
|
982 | qw(io timer time now now_update signal child idle condvar one_event DESTROY); |
|
|
983 | |
|
|
984 | our @post_detect; |
|
|
985 | |
|
|
986 | sub post_detect(&) { |
|
|
987 | my ($cb) = @_; |
|
|
988 | |
|
|
989 | if ($MODEL) { |
|
|
990 | $cb->(); |
|
|
991 | |
|
|
992 | 1 |
|
|
993 | } else { |
|
|
994 | push @post_detect, $cb; |
|
|
995 | |
|
|
996 | defined wantarray |
|
|
997 | ? bless \$cb, "AnyEvent::Util::postdetect" |
|
|
998 | : () |
|
|
999 | } |
|
|
1000 | } |
|
|
1001 | |
|
|
1002 | sub AnyEvent::Util::postdetect::DESTROY { |
|
|
1003 | @post_detect = grep $_ != ${$_[0]}, @post_detect; |
|
|
1004 | } |
703 | |
1005 | |
704 | sub detect() { |
1006 | sub detect() { |
705 | unless ($MODEL) { |
1007 | unless ($MODEL) { |
706 | no strict 'refs'; |
1008 | no strict 'refs'; |
|
|
1009 | local $SIG{__DIE__}; |
707 | |
1010 | |
708 | if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { |
1011 | if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { |
709 | my $model = "AnyEvent::Impl::$1"; |
1012 | my $model = "AnyEvent::Impl::$1"; |
710 | if (eval "require $model") { |
1013 | if (eval "require $model") { |
711 | $MODEL = $model; |
1014 | $MODEL = $model; |
… | |
… | |
741 | last; |
1044 | last; |
742 | } |
1045 | } |
743 | } |
1046 | } |
744 | |
1047 | |
745 | $MODEL |
1048 | $MODEL |
746 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib."; |
1049 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n"; |
747 | } |
1050 | } |
748 | } |
1051 | } |
749 | |
1052 | |
|
|
1053 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
|
|
1054 | |
750 | unshift @ISA, $MODEL; |
1055 | unshift @ISA, $MODEL; |
751 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
1056 | |
|
|
1057 | require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT}; |
|
|
1058 | |
|
|
1059 | (shift @post_detect)->() while @post_detect; |
752 | } |
1060 | } |
753 | |
1061 | |
754 | $MODEL |
1062 | $MODEL |
755 | } |
1063 | } |
756 | |
1064 | |
… | |
… | |
764 | |
1072 | |
765 | my $class = shift; |
1073 | my $class = shift; |
766 | $class->$func (@_); |
1074 | $class->$func (@_); |
767 | } |
1075 | } |
768 | |
1076 | |
|
|
1077 | # utility function to dup a filehandle. this is used by many backends |
|
|
1078 | # to support binding more than one watcher per filehandle (they usually |
|
|
1079 | # allow only one watcher per fd, so we dup it to get a different one). |
|
|
1080 | sub _dupfh($$$$) { |
|
|
1081 | my ($poll, $fh, $r, $w) = @_; |
|
|
1082 | |
|
|
1083 | # cygwin requires the fh mode to be matching, unix doesn't |
|
|
1084 | my ($rw, $mode) = $poll eq "r" ? ($r, "<") |
|
|
1085 | : $poll eq "w" ? ($w, ">") |
|
|
1086 | : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'"; |
|
|
1087 | |
|
|
1088 | open my $fh2, "$mode&" . fileno $fh |
|
|
1089 | or die "cannot dup() filehandle: $!,"; |
|
|
1090 | |
|
|
1091 | # we assume CLOEXEC is already set by perl in all important cases |
|
|
1092 | |
|
|
1093 | ($fh2, $rw) |
|
|
1094 | } |
|
|
1095 | |
769 | package AnyEvent::Base; |
1096 | package AnyEvent::Base; |
770 | |
1097 | |
|
|
1098 | # default implementations for many methods |
|
|
1099 | |
|
|
1100 | BEGIN { |
|
|
1101 | if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { |
|
|
1102 | *_time = \&Time::HiRes::time; |
|
|
1103 | # if (eval "use POSIX (); (POSIX::times())... |
|
|
1104 | } else { |
|
|
1105 | *_time = sub { time }; # epic fail |
|
|
1106 | } |
|
|
1107 | } |
|
|
1108 | |
|
|
1109 | sub time { _time } |
|
|
1110 | sub now { _time } |
|
|
1111 | sub now_update { } |
|
|
1112 | |
771 | # default implementation for ->condvar, ->wait, ->broadcast |
1113 | # default implementation for ->condvar |
772 | |
1114 | |
773 | sub condvar { |
1115 | sub condvar { |
774 | bless \my $flag, "AnyEvent::Base::CondVar" |
1116 | bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" |
775 | } |
|
|
776 | |
|
|
777 | sub AnyEvent::Base::CondVar::broadcast { |
|
|
778 | ${$_[0]}++; |
|
|
779 | } |
|
|
780 | |
|
|
781 | sub AnyEvent::Base::CondVar::wait { |
|
|
782 | AnyEvent->one_event while !${$_[0]}; |
|
|
783 | } |
1117 | } |
784 | |
1118 | |
785 | # default implementation for ->signal |
1119 | # default implementation for ->signal |
786 | |
1120 | |
787 | our %SIG_CB; |
1121 | our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); |
|
|
1122 | |
|
|
1123 | sub _signal_exec { |
|
|
1124 | sysread $SIGPIPE_R, my $dummy, 4; |
|
|
1125 | |
|
|
1126 | while (%SIG_EV) { |
|
|
1127 | for (keys %SIG_EV) { |
|
|
1128 | delete $SIG_EV{$_}; |
|
|
1129 | $_->() for values %{ $SIG_CB{$_} || {} }; |
|
|
1130 | } |
|
|
1131 | } |
|
|
1132 | } |
788 | |
1133 | |
789 | sub signal { |
1134 | sub signal { |
790 | my (undef, %arg) = @_; |
1135 | my (undef, %arg) = @_; |
791 | |
1136 | |
|
|
1137 | unless ($SIGPIPE_R) { |
|
|
1138 | require Fcntl; |
|
|
1139 | |
|
|
1140 | if (AnyEvent::WIN32) { |
|
|
1141 | require AnyEvent::Util; |
|
|
1142 | |
|
|
1143 | ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe (); |
|
|
1144 | AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R; |
|
|
1145 | AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case |
|
|
1146 | } else { |
|
|
1147 | pipe $SIGPIPE_R, $SIGPIPE_W; |
|
|
1148 | fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R; |
|
|
1149 | fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case |
|
|
1150 | |
|
|
1151 | # not strictly required, as $^F is normally 2, but let's make sure... |
|
|
1152 | fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC; |
|
|
1153 | fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC; |
|
|
1154 | } |
|
|
1155 | |
|
|
1156 | $SIGPIPE_R |
|
|
1157 | or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; |
|
|
1158 | |
|
|
1159 | $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec); |
|
|
1160 | } |
|
|
1161 | |
792 | my $signal = uc $arg{signal} |
1162 | my $signal = uc $arg{signal} |
793 | or Carp::croak "required option 'signal' is missing"; |
1163 | or Carp::croak "required option 'signal' is missing"; |
794 | |
1164 | |
795 | $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; |
1165 | $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; |
796 | $SIG{$signal} ||= sub { |
1166 | $SIG{$signal} ||= sub { |
797 | $_->() for values %{ $SIG_CB{$signal} || {} }; |
1167 | local $!; |
|
|
1168 | syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; |
|
|
1169 | undef $SIG_EV{$signal}; |
798 | }; |
1170 | }; |
799 | |
1171 | |
800 | bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" |
1172 | bless [$signal, $arg{cb}], "AnyEvent::Base::signal" |
801 | } |
1173 | } |
802 | |
1174 | |
803 | sub AnyEvent::Base::Signal::DESTROY { |
1175 | sub AnyEvent::Base::signal::DESTROY { |
804 | my ($signal, $cb) = @{$_[0]}; |
1176 | my ($signal, $cb) = @{$_[0]}; |
805 | |
1177 | |
806 | delete $SIG_CB{$signal}{$cb}; |
1178 | delete $SIG_CB{$signal}{$cb}; |
807 | |
1179 | |
|
|
1180 | # delete doesn't work with older perls - they then |
|
|
1181 | # print weird messages, or just unconditionally exit |
|
|
1182 | # instead of getting the default action. |
808 | $SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} }; |
1183 | undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} }; |
809 | } |
1184 | } |
810 | |
1185 | |
811 | # default implementation for ->child |
1186 | # default implementation for ->child |
812 | |
1187 | |
813 | our %PID_CB; |
1188 | our %PID_CB; |
814 | our $CHLD_W; |
1189 | our $CHLD_W; |
815 | our $CHLD_DELAY_W; |
1190 | our $CHLD_DELAY_W; |
816 | our $PID_IDLE; |
|
|
817 | our $WNOHANG; |
1191 | our $WNOHANG; |
818 | |
1192 | |
819 | sub _child_wait { |
1193 | sub _sigchld { |
820 | while (0 < (my $pid = waitpid -1, $WNOHANG)) { |
1194 | while (0 < (my $pid = waitpid -1, $WNOHANG)) { |
821 | $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), |
1195 | $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), |
822 | (values %{ $PID_CB{0} || {} }); |
1196 | (values %{ $PID_CB{0} || {} }); |
823 | } |
1197 | } |
824 | |
|
|
825 | undef $PID_IDLE; |
|
|
826 | } |
|
|
827 | |
|
|
828 | sub _sigchld { |
|
|
829 | # make sure we deliver these changes "synchronous" with the event loop. |
|
|
830 | $CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub { |
|
|
831 | undef $CHLD_DELAY_W; |
|
|
832 | &_child_wait; |
|
|
833 | }); |
|
|
834 | } |
1198 | } |
835 | |
1199 | |
836 | sub child { |
1200 | sub child { |
837 | my (undef, %arg) = @_; |
1201 | my (undef, %arg) = @_; |
838 | |
1202 | |
839 | defined (my $pid = $arg{pid} + 0) |
1203 | defined (my $pid = $arg{pid} + 0) |
840 | or Carp::croak "required option 'pid' is missing"; |
1204 | or Carp::croak "required option 'pid' is missing"; |
841 | |
1205 | |
842 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
1206 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
843 | |
1207 | |
844 | unless ($WNOHANG) { |
|
|
845 | $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1; |
1208 | $WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; |
846 | } |
|
|
847 | |
1209 | |
848 | unless ($CHLD_W) { |
1210 | unless ($CHLD_W) { |
849 | $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); |
1211 | $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); |
850 | # child could be a zombie already, so make at least one round |
1212 | # child could be a zombie already, so make at least one round |
851 | &_sigchld; |
1213 | &_sigchld; |
852 | } |
1214 | } |
853 | |
1215 | |
854 | bless [$pid, $arg{cb}], "AnyEvent::Base::Child" |
1216 | bless [$pid, $arg{cb}], "AnyEvent::Base::child" |
855 | } |
1217 | } |
856 | |
1218 | |
857 | sub AnyEvent::Base::Child::DESTROY { |
1219 | sub AnyEvent::Base::child::DESTROY { |
858 | my ($pid, $cb) = @{$_[0]}; |
1220 | my ($pid, $cb) = @{$_[0]}; |
859 | |
1221 | |
860 | delete $PID_CB{$pid}{$cb}; |
1222 | delete $PID_CB{$pid}{$cb}; |
861 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
1223 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
862 | |
1224 | |
863 | undef $CHLD_W unless keys %PID_CB; |
1225 | undef $CHLD_W unless keys %PID_CB; |
864 | } |
1226 | } |
|
|
1227 | |
|
|
1228 | # idle emulation is done by simply using a timer, regardless |
|
|
1229 | # of whether the process is idle or not, and not letting |
|
|
1230 | # the callback use more than 50% of the time. |
|
|
1231 | sub idle { |
|
|
1232 | my (undef, %arg) = @_; |
|
|
1233 | |
|
|
1234 | my ($cb, $w, $rcb) = $arg{cb}; |
|
|
1235 | |
|
|
1236 | $rcb = sub { |
|
|
1237 | if ($cb) { |
|
|
1238 | $w = _time; |
|
|
1239 | &$cb; |
|
|
1240 | $w = _time - $w; |
|
|
1241 | |
|
|
1242 | # never use more then 50% of the time for the idle watcher, |
|
|
1243 | # within some limits |
|
|
1244 | $w = 0.0001 if $w < 0.0001; |
|
|
1245 | $w = 5 if $w > 5; |
|
|
1246 | |
|
|
1247 | $w = AnyEvent->timer (after => $w, cb => $rcb); |
|
|
1248 | } else { |
|
|
1249 | # clean up... |
|
|
1250 | undef $w; |
|
|
1251 | undef $rcb; |
|
|
1252 | } |
|
|
1253 | }; |
|
|
1254 | |
|
|
1255 | $w = AnyEvent->timer (after => 0.05, cb => $rcb); |
|
|
1256 | |
|
|
1257 | bless \\$cb, "AnyEvent::Base::idle" |
|
|
1258 | } |
|
|
1259 | |
|
|
1260 | sub AnyEvent::Base::idle::DESTROY { |
|
|
1261 | undef $${$_[0]}; |
|
|
1262 | } |
|
|
1263 | |
|
|
1264 | package AnyEvent::CondVar; |
|
|
1265 | |
|
|
1266 | our @ISA = AnyEvent::CondVar::Base::; |
|
|
1267 | |
|
|
1268 | package AnyEvent::CondVar::Base; |
|
|
1269 | |
|
|
1270 | use overload |
|
|
1271 | '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, |
|
|
1272 | fallback => 1; |
|
|
1273 | |
|
|
1274 | sub _send { |
|
|
1275 | # nop |
|
|
1276 | } |
|
|
1277 | |
|
|
1278 | sub send { |
|
|
1279 | my $cv = shift; |
|
|
1280 | $cv->{_ae_sent} = [@_]; |
|
|
1281 | (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb}; |
|
|
1282 | $cv->_send; |
|
|
1283 | } |
|
|
1284 | |
|
|
1285 | sub croak { |
|
|
1286 | $_[0]{_ae_croak} = $_[1]; |
|
|
1287 | $_[0]->send; |
|
|
1288 | } |
|
|
1289 | |
|
|
1290 | sub ready { |
|
|
1291 | $_[0]{_ae_sent} |
|
|
1292 | } |
|
|
1293 | |
|
|
1294 | sub _wait { |
|
|
1295 | AnyEvent->one_event while !$_[0]{_ae_sent}; |
|
|
1296 | } |
|
|
1297 | |
|
|
1298 | sub recv { |
|
|
1299 | $_[0]->_wait; |
|
|
1300 | |
|
|
1301 | Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; |
|
|
1302 | wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] |
|
|
1303 | } |
|
|
1304 | |
|
|
1305 | sub cb { |
|
|
1306 | $_[0]{_ae_cb} = $_[1] if @_ > 1; |
|
|
1307 | $_[0]{_ae_cb} |
|
|
1308 | } |
|
|
1309 | |
|
|
1310 | sub begin { |
|
|
1311 | ++$_[0]{_ae_counter}; |
|
|
1312 | $_[0]{_ae_end_cb} = $_[1] if @_ > 1; |
|
|
1313 | } |
|
|
1314 | |
|
|
1315 | sub end { |
|
|
1316 | return if --$_[0]{_ae_counter}; |
|
|
1317 | &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } }; |
|
|
1318 | } |
|
|
1319 | |
|
|
1320 | # undocumented/compatibility with pre-3.4 |
|
|
1321 | *broadcast = \&send; |
|
|
1322 | *wait = \&_wait; |
|
|
1323 | |
|
|
1324 | =head1 ERROR AND EXCEPTION HANDLING |
|
|
1325 | |
|
|
1326 | In general, AnyEvent does not do any error handling - it relies on the |
|
|
1327 | caller to do that if required. The L<AnyEvent::Strict> module (see also |
|
|
1328 | the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict |
|
|
1329 | checking of all AnyEvent methods, however, which is highly useful during |
|
|
1330 | development. |
|
|
1331 | |
|
|
1332 | As for exception handling (i.e. runtime errors and exceptions thrown while |
|
|
1333 | executing a callback), this is not only highly event-loop specific, but |
|
|
1334 | also not in any way wrapped by this module, as this is the job of the main |
|
|
1335 | program. |
|
|
1336 | |
|
|
1337 | The pure perl event loop simply re-throws the exception (usually |
|
|
1338 | within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<< |
|
|
1339 | $Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and |
|
|
1340 | so on. |
|
|
1341 | |
|
|
1342 | =head1 ENVIRONMENT VARIABLES |
|
|
1343 | |
|
|
1344 | The following environment variables are used by this module or its |
|
|
1345 | submodules. |
|
|
1346 | |
|
|
1347 | Note that AnyEvent will remove I<all> environment variables starting with |
|
|
1348 | C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is |
|
|
1349 | enabled. |
|
|
1350 | |
|
|
1351 | =over 4 |
|
|
1352 | |
|
|
1353 | =item C<PERL_ANYEVENT_VERBOSE> |
|
|
1354 | |
|
|
1355 | By default, AnyEvent will be completely silent except in fatal |
|
|
1356 | conditions. You can set this environment variable to make AnyEvent more |
|
|
1357 | talkative. |
|
|
1358 | |
|
|
1359 | When set to C<1> or higher, causes AnyEvent to warn about unexpected |
|
|
1360 | conditions, such as not being able to load the event model specified by |
|
|
1361 | C<PERL_ANYEVENT_MODEL>. |
|
|
1362 | |
|
|
1363 | When set to C<2> or higher, cause AnyEvent to report to STDERR which event |
|
|
1364 | model it chooses. |
|
|
1365 | |
|
|
1366 | =item C<PERL_ANYEVENT_STRICT> |
|
|
1367 | |
|
|
1368 | AnyEvent does not do much argument checking by default, as thorough |
|
|
1369 | argument checking is very costly. Setting this variable to a true value |
|
|
1370 | will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly |
|
|
1371 | check the arguments passed to most method calls. If it finds any problems |
|
|
1372 | it will croak. |
|
|
1373 | |
|
|
1374 | In other words, enables "strict" mode. |
|
|
1375 | |
|
|
1376 | Unlike C<use strict>, it is definitely recommended ot keep it off in |
|
|
1377 | production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while |
|
|
1378 | developing programs can be very useful, however. |
|
|
1379 | |
|
|
1380 | =item C<PERL_ANYEVENT_MODEL> |
|
|
1381 | |
|
|
1382 | This can be used to specify the event model to be used by AnyEvent, before |
|
|
1383 | auto detection and -probing kicks in. It must be a string consisting |
|
|
1384 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
|
|
1385 | and the resulting module name is loaded and if the load was successful, |
|
|
1386 | used as event model. If it fails to load AnyEvent will proceed with |
|
|
1387 | auto detection and -probing. |
|
|
1388 | |
|
|
1389 | This functionality might change in future versions. |
|
|
1390 | |
|
|
1391 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
|
|
1392 | could start your program like this: |
|
|
1393 | |
|
|
1394 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
1395 | |
|
|
1396 | =item C<PERL_ANYEVENT_PROTOCOLS> |
|
|
1397 | |
|
|
1398 | Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences |
|
|
1399 | for IPv4 or IPv6. The default is unspecified (and might change, or be the result |
|
|
1400 | of auto probing). |
|
|
1401 | |
|
|
1402 | Must be set to a comma-separated list of protocols or address families, |
|
|
1403 | current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be |
|
|
1404 | used, and preference will be given to protocols mentioned earlier in the |
|
|
1405 | list. |
|
|
1406 | |
|
|
1407 | This variable can effectively be used for denial-of-service attacks |
|
|
1408 | against local programs (e.g. when setuid), although the impact is likely |
|
|
1409 | small, as the program has to handle conenction and other failures anyways. |
|
|
1410 | |
|
|
1411 | Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6, |
|
|
1412 | but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> |
|
|
1413 | - only support IPv4, never try to resolve or contact IPv6 |
|
|
1414 | addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or |
|
|
1415 | IPv6, but prefer IPv6 over IPv4. |
|
|
1416 | |
|
|
1417 | =item C<PERL_ANYEVENT_EDNS0> |
|
|
1418 | |
|
|
1419 | Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension |
|
|
1420 | for DNS. This extension is generally useful to reduce DNS traffic, but |
|
|
1421 | some (broken) firewalls drop such DNS packets, which is why it is off by |
|
|
1422 | default. |
|
|
1423 | |
|
|
1424 | Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce |
|
|
1425 | EDNS0 in its DNS requests. |
|
|
1426 | |
|
|
1427 | =item C<PERL_ANYEVENT_MAX_FORKS> |
|
|
1428 | |
|
|
1429 | The maximum number of child processes that C<AnyEvent::Util::fork_call> |
|
|
1430 | will create in parallel. |
|
|
1431 | |
|
|
1432 | =back |
865 | |
1433 | |
866 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
1434 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
867 | |
1435 | |
868 | This is an advanced topic that you do not normally need to use AnyEvent in |
1436 | This is an advanced topic that you do not normally need to use AnyEvent in |
869 | a module. This section is only of use to event loop authors who want to |
1437 | a module. This section is only of use to event loop authors who want to |
… | |
… | |
903 | |
1471 | |
904 | I<rxvt-unicode> also cheats a bit by not providing blocking access to |
1472 | I<rxvt-unicode> also cheats a bit by not providing blocking access to |
905 | condition variables: code blocking while waiting for a condition will |
1473 | condition variables: code blocking while waiting for a condition will |
906 | C<die>. This still works with most modules/usages, and blocking calls must |
1474 | C<die>. This still works with most modules/usages, and blocking calls must |
907 | not be done in an interactive application, so it makes sense. |
1475 | not be done in an interactive application, so it makes sense. |
908 | |
|
|
909 | =head1 ENVIRONMENT VARIABLES |
|
|
910 | |
|
|
911 | The following environment variables are used by this module: |
|
|
912 | |
|
|
913 | =over 4 |
|
|
914 | |
|
|
915 | =item C<PERL_ANYEVENT_VERBOSE> |
|
|
916 | |
|
|
917 | By default, AnyEvent will be completely silent except in fatal |
|
|
918 | conditions. You can set this environment variable to make AnyEvent more |
|
|
919 | talkative. |
|
|
920 | |
|
|
921 | When set to C<1> or higher, causes AnyEvent to warn about unexpected |
|
|
922 | conditions, such as not being able to load the event model specified by |
|
|
923 | C<PERL_ANYEVENT_MODEL>. |
|
|
924 | |
|
|
925 | When set to C<2> or higher, cause AnyEvent to report to STDERR which event |
|
|
926 | model it chooses. |
|
|
927 | |
|
|
928 | =item C<PERL_ANYEVENT_MODEL> |
|
|
929 | |
|
|
930 | This can be used to specify the event model to be used by AnyEvent, before |
|
|
931 | autodetection and -probing kicks in. It must be a string consisting |
|
|
932 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
|
|
933 | and the resulting module name is loaded and if the load was successful, |
|
|
934 | used as event model. If it fails to load AnyEvent will proceed with |
|
|
935 | autodetection and -probing. |
|
|
936 | |
|
|
937 | This functionality might change in future versions. |
|
|
938 | |
|
|
939 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
|
|
940 | could start your program like this: |
|
|
941 | |
|
|
942 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
943 | |
|
|
944 | =back |
|
|
945 | |
1476 | |
946 | =head1 EXAMPLE PROGRAM |
1477 | =head1 EXAMPLE PROGRAM |
947 | |
1478 | |
948 | The following program uses an I/O watcher to read data from STDIN, a timer |
1479 | The following program uses an I/O watcher to read data from STDIN, a timer |
949 | to display a message once per second, and a condition variable to quit the |
1480 | to display a message once per second, and a condition variable to quit the |
… | |
… | |
958 | poll => 'r', |
1489 | poll => 'r', |
959 | cb => sub { |
1490 | cb => sub { |
960 | warn "io event <$_[0]>\n"; # will always output <r> |
1491 | warn "io event <$_[0]>\n"; # will always output <r> |
961 | chomp (my $input = <STDIN>); # read a line |
1492 | chomp (my $input = <STDIN>); # read a line |
962 | warn "read: $input\n"; # output what has been read |
1493 | warn "read: $input\n"; # output what has been read |
963 | $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i |
1494 | $cv->send if $input =~ /^q/i; # quit program if /^q/i |
964 | }, |
1495 | }, |
965 | ); |
1496 | ); |
966 | |
1497 | |
967 | my $time_watcher; # can only be used once |
1498 | my $time_watcher; # can only be used once |
968 | |
1499 | |
… | |
… | |
973 | }); |
1504 | }); |
974 | } |
1505 | } |
975 | |
1506 | |
976 | new_timer; # create first timer |
1507 | new_timer; # create first timer |
977 | |
1508 | |
978 | $cv->wait; # wait until user enters /^q/i |
1509 | $cv->recv; # wait until user enters /^q/i |
979 | |
1510 | |
980 | =head1 REAL-WORLD EXAMPLE |
1511 | =head1 REAL-WORLD EXAMPLE |
981 | |
1512 | |
982 | Consider the L<Net::FCP> module. It features (among others) the following |
1513 | Consider the L<Net::FCP> module. It features (among others) the following |
983 | API calls, which are to freenet what HTTP GET requests are to http: |
1514 | API calls, which are to freenet what HTTP GET requests are to http: |
… | |
… | |
1033 | syswrite $txn->{fh}, $txn->{request} |
1564 | syswrite $txn->{fh}, $txn->{request} |
1034 | or die "connection or write error"; |
1565 | or die "connection or write error"; |
1035 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
1566 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
1036 | |
1567 | |
1037 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
1568 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
1038 | result and signals any possible waiters that the request ahs finished: |
1569 | result and signals any possible waiters that the request has finished: |
1039 | |
1570 | |
1040 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
1571 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
1041 | |
1572 | |
1042 | if (end-of-file or data complete) { |
1573 | if (end-of-file or data complete) { |
1043 | $txn->{result} = $txn->{buf}; |
1574 | $txn->{result} = $txn->{buf}; |
1044 | $txn->{finished}->broadcast; |
1575 | $txn->{finished}->send; |
1045 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
1576 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
1046 | } |
1577 | } |
1047 | |
1578 | |
1048 | The C<result> method, finally, just waits for the finished signal (if the |
1579 | The C<result> method, finally, just waits for the finished signal (if the |
1049 | request was already finished, it doesn't wait, of course, and returns the |
1580 | request was already finished, it doesn't wait, of course, and returns the |
1050 | data: |
1581 | data: |
1051 | |
1582 | |
1052 | $txn->{finished}->wait; |
1583 | $txn->{finished}->recv; |
1053 | return $txn->{result}; |
1584 | return $txn->{result}; |
1054 | |
1585 | |
1055 | The actual code goes further and collects all errors (C<die>s, exceptions) |
1586 | The actual code goes further and collects all errors (C<die>s, exceptions) |
1056 | that occured during request processing. The C<result> method detects |
1587 | that occurred during request processing. The C<result> method detects |
1057 | whether an exception as thrown (it is stored inside the $txn object) |
1588 | whether an exception as thrown (it is stored inside the $txn object) |
1058 | and just throws the exception, which means connection errors and other |
1589 | and just throws the exception, which means connection errors and other |
1059 | problems get reported tot he code that tries to use the result, not in a |
1590 | problems get reported tot he code that tries to use the result, not in a |
1060 | random callback. |
1591 | random callback. |
1061 | |
1592 | |
… | |
… | |
1092 | |
1623 | |
1093 | my $quit = AnyEvent->condvar; |
1624 | my $quit = AnyEvent->condvar; |
1094 | |
1625 | |
1095 | $fcp->txn_client_get ($url)->cb (sub { |
1626 | $fcp->txn_client_get ($url)->cb (sub { |
1096 | ... |
1627 | ... |
1097 | $quit->broadcast; |
1628 | $quit->send; |
1098 | }); |
1629 | }); |
1099 | |
1630 | |
1100 | $quit->wait; |
1631 | $quit->recv; |
1101 | |
1632 | |
1102 | |
1633 | |
1103 | =head1 BENCHMARKS |
1634 | =head1 BENCHMARKS |
1104 | |
1635 | |
1105 | To give you an idea of the performance and overheads that AnyEvent adds |
1636 | To give you an idea of the performance and overheads that AnyEvent adds |
… | |
… | |
1107 | of various event loops I prepared some benchmarks. |
1638 | of various event loops I prepared some benchmarks. |
1108 | |
1639 | |
1109 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
1640 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
1110 | |
1641 | |
1111 | Here is a benchmark of various supported event models used natively and |
1642 | Here is a benchmark of various supported event models used natively and |
1112 | through anyevent. The benchmark creates a lot of timers (with a zero |
1643 | through AnyEvent. The benchmark creates a lot of timers (with a zero |
1113 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
1644 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
1114 | which it is), lets them fire exactly once and destroys them again. |
1645 | which it is), lets them fire exactly once and destroys them again. |
1115 | |
1646 | |
1116 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
1647 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
1117 | distribution. |
1648 | distribution. |
… | |
… | |
1134 | all watchers, to avoid adding memory overhead. That means closure creation |
1665 | all watchers, to avoid adding memory overhead. That means closure creation |
1135 | and memory usage is not included in the figures. |
1666 | and memory usage is not included in the figures. |
1136 | |
1667 | |
1137 | I<invoke> is the time, in microseconds, used to invoke a simple |
1668 | I<invoke> is the time, in microseconds, used to invoke a simple |
1138 | callback. The callback simply counts down a Perl variable and after it was |
1669 | callback. The callback simply counts down a Perl variable and after it was |
1139 | invoked "watcher" times, it would C<< ->broadcast >> a condvar once to |
1670 | invoked "watcher" times, it would C<< ->send >> a condvar once to |
1140 | signal the end of this phase. |
1671 | signal the end of this phase. |
1141 | |
1672 | |
1142 | I<destroy> is the time, in microseconds, that it takes to destroy a single |
1673 | I<destroy> is the time, in microseconds, that it takes to destroy a single |
1143 | watcher. |
1674 | watcher. |
1144 | |
1675 | |
1145 | =head3 Results |
1676 | =head3 Results |
1146 | |
1677 | |
1147 | name watchers bytes create invoke destroy comment |
1678 | name watchers bytes create invoke destroy comment |
1148 | EV/EV 400000 244 0.56 0.46 0.31 EV native interface |
1679 | EV/EV 400000 224 0.47 0.35 0.27 EV native interface |
1149 | EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers |
1680 | EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers |
1150 | CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal |
1681 | CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal |
1151 | Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation |
1682 | Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation |
1152 | Event/Event 16000 516 31.88 31.30 0.85 Event native interface |
1683 | Event/Event 16000 517 32.20 31.80 0.81 Event native interface |
1153 | Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers |
1684 | Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers |
1154 | Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour |
1685 | Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour |
1155 | Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers |
1686 | Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers |
1156 | POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event |
1687 | POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event |
1157 | POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select |
1688 | POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select |
1158 | |
1689 | |
1159 | =head3 Discussion |
1690 | =head3 Discussion |
1160 | |
1691 | |
1161 | The benchmark does I<not> measure scalability of the event loop very |
1692 | The benchmark does I<not> measure scalability of the event loop very |
1162 | well. For example, a select-based event loop (such as the pure perl one) |
1693 | well. For example, a select-based event loop (such as the pure perl one) |
… | |
… | |
1240 | |
1771 | |
1241 | =back |
1772 | =back |
1242 | |
1773 | |
1243 | =head2 BENCHMARKING THE LARGE SERVER CASE |
1774 | =head2 BENCHMARKING THE LARGE SERVER CASE |
1244 | |
1775 | |
1245 | This benchmark atcually benchmarks the event loop itself. It works by |
1776 | This benchmark actually benchmarks the event loop itself. It works by |
1246 | creating a number of "servers": each server consists of a socketpair, a |
1777 | creating a number of "servers": each server consists of a socket pair, a |
1247 | timeout watcher that gets reset on activity (but never fires), and an I/O |
1778 | timeout watcher that gets reset on activity (but never fires), and an I/O |
1248 | watcher waiting for input on one side of the socket. Each time the socket |
1779 | watcher waiting for input on one side of the socket. Each time the socket |
1249 | watcher reads a byte it will write that byte to a random other "server". |
1780 | watcher reads a byte it will write that byte to a random other "server". |
1250 | |
1781 | |
1251 | The effect is that there will be a lot of I/O watchers, only part of which |
1782 | The effect is that there will be a lot of I/O watchers, only part of which |
1252 | are active at any one point (so there is a constant number of active |
1783 | are active at any one point (so there is a constant number of active |
1253 | fds for each loop iterstaion, but which fds these are is random). The |
1784 | fds for each loop iteration, but which fds these are is random). The |
1254 | timeout is reset each time something is read because that reflects how |
1785 | timeout is reset each time something is read because that reflects how |
1255 | most timeouts work (and puts extra pressure on the event loops). |
1786 | most timeouts work (and puts extra pressure on the event loops). |
1256 | |
1787 | |
1257 | In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100 |
1788 | In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 |
1258 | (1%) are active. This mirrors the activity of large servers with many |
1789 | (1%) are active. This mirrors the activity of large servers with many |
1259 | connections, most of which are idle at any one point in time. |
1790 | connections, most of which are idle at any one point in time. |
1260 | |
1791 | |
1261 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
1792 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
1262 | distribution. |
1793 | distribution. |
… | |
… | |
1264 | =head3 Explanation of the columns |
1795 | =head3 Explanation of the columns |
1265 | |
1796 | |
1266 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
1797 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
1267 | each server has a read and write socket end). |
1798 | each server has a read and write socket end). |
1268 | |
1799 | |
1269 | I<create> is the time it takes to create a socketpair (which is |
1800 | I<create> is the time it takes to create a socket pair (which is |
1270 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
1801 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
1271 | |
1802 | |
1272 | I<request>, the most important value, is the time it takes to handle a |
1803 | I<request>, the most important value, is the time it takes to handle a |
1273 | single "request", that is, reading the token from the pipe and forwarding |
1804 | single "request", that is, reading the token from the pipe and forwarding |
1274 | it to another server. This includes deleting the old timeout and creating |
1805 | it to another server. This includes deleting the old timeout and creating |
… | |
… | |
1347 | speed most when you have lots of watchers, not when you only have a few of |
1878 | speed most when you have lots of watchers, not when you only have a few of |
1348 | them). |
1879 | them). |
1349 | |
1880 | |
1350 | EV is again fastest. |
1881 | EV is again fastest. |
1351 | |
1882 | |
1352 | Perl again comes second. It is noticably faster than the C-based event |
1883 | Perl again comes second. It is noticeably faster than the C-based event |
1353 | loops Event and Glib, although the difference is too small to really |
1884 | loops Event and Glib, although the difference is too small to really |
1354 | matter. |
1885 | matter. |
1355 | |
1886 | |
1356 | POE also performs much better in this case, but is is still far behind the |
1887 | POE also performs much better in this case, but is is still far behind the |
1357 | others. |
1888 | others. |
… | |
… | |
1362 | |
1893 | |
1363 | =item * C-based event loops perform very well with small number of |
1894 | =item * C-based event loops perform very well with small number of |
1364 | watchers, as the management overhead dominates. |
1895 | watchers, as the management overhead dominates. |
1365 | |
1896 | |
1366 | =back |
1897 | =back |
|
|
1898 | |
|
|
1899 | =head2 THE IO::Lambda BENCHMARK |
|
|
1900 | |
|
|
1901 | Recently I was told about the benchmark in the IO::Lambda manpage, which |
|
|
1902 | could be misinterpreted to make AnyEvent look bad. In fact, the benchmark |
|
|
1903 | simply compares IO::Lambda with POE, and IO::Lambda looks better (which |
|
|
1904 | shouldn't come as a surprise to anybody). As such, the benchmark is |
|
|
1905 | fine, and shows that the AnyEvent backend from IO::Lambda isn't very |
|
|
1906 | optimal. But how would AnyEvent compare when used without the extra |
|
|
1907 | baggage? To explore this, I wrote the equivalent benchmark for AnyEvent. |
|
|
1908 | |
|
|
1909 | The benchmark itself creates an echo-server, and then, for 500 times, |
|
|
1910 | connects to the echo server, sends a line, waits for the reply, and then |
|
|
1911 | creates the next connection. This is a rather bad benchmark, as it doesn't |
|
|
1912 | test the efficiency of the framework, but it is a benchmark nevertheless. |
|
|
1913 | |
|
|
1914 | name runtime |
|
|
1915 | Lambda/select 0.330 sec |
|
|
1916 | + optimized 0.122 sec |
|
|
1917 | Lambda/AnyEvent 0.327 sec |
|
|
1918 | + optimized 0.138 sec |
|
|
1919 | Raw sockets/select 0.077 sec |
|
|
1920 | POE/select, components 0.662 sec |
|
|
1921 | POE/select, raw sockets 0.226 sec |
|
|
1922 | POE/select, optimized 0.404 sec |
|
|
1923 | |
|
|
1924 | AnyEvent/select/nb 0.085 sec |
|
|
1925 | AnyEvent/EV/nb 0.068 sec |
|
|
1926 | +state machine 0.134 sec |
|
|
1927 | |
|
|
1928 | The benchmark is also a bit unfair (my fault) - the IO::Lambda |
|
|
1929 | benchmarks actually make blocking connects and use 100% blocking I/O, |
|
|
1930 | defeating the purpose of an event-based solution. All of the newly |
|
|
1931 | written AnyEvent benchmarks use 100% non-blocking connects (using |
|
|
1932 | AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS |
|
|
1933 | resolver), so AnyEvent is at a disadvantage here as non-blocking connects |
|
|
1934 | generally require a lot more bookkeeping and event handling than blocking |
|
|
1935 | connects (which involve a single syscall only). |
|
|
1936 | |
|
|
1937 | The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which |
|
|
1938 | offers similar expressive power as POE and IO::Lambda (using conventional |
|
|
1939 | Perl syntax), which means both the echo server and the client are 100% |
|
|
1940 | non-blocking w.r.t. I/O, further placing it at a disadvantage. |
|
|
1941 | |
|
|
1942 | As you can see, AnyEvent + EV even beats the hand-optimised "raw sockets |
|
|
1943 | benchmark", while AnyEvent + its pure perl backend easily beats |
|
|
1944 | IO::Lambda and POE. |
|
|
1945 | |
|
|
1946 | And even the 100% non-blocking version written using the high-level (and |
|
|
1947 | slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda, |
|
|
1948 | even thought it does all of DNS, tcp-connect and socket I/O in a |
|
|
1949 | non-blocking way. |
|
|
1950 | |
|
|
1951 | The two AnyEvent benchmarks can be found as F<eg/ae0.pl> and F<eg/ae2.pl> |
|
|
1952 | in the AnyEvent distribution, the remaining benchmarks are part of the |
|
|
1953 | IO::lambda distribution and were used without any changes. |
|
|
1954 | |
|
|
1955 | |
|
|
1956 | =head1 SIGNALS |
|
|
1957 | |
|
|
1958 | AnyEvent currently installs handlers for these signals: |
|
|
1959 | |
|
|
1960 | =over 4 |
|
|
1961 | |
|
|
1962 | =item SIGCHLD |
|
|
1963 | |
|
|
1964 | A handler for C<SIGCHLD> is installed by AnyEvent's child watcher |
|
|
1965 | emulation for event loops that do not support them natively. Also, some |
|
|
1966 | event loops install a similar handler. |
|
|
1967 | |
|
|
1968 | =item SIGPIPE |
|
|
1969 | |
|
|
1970 | A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> |
|
|
1971 | when AnyEvent gets loaded. |
|
|
1972 | |
|
|
1973 | The rationale for this is that AnyEvent users usually do not really depend |
|
|
1974 | on SIGPIPE delivery (which is purely an optimisation for shell use, or |
|
|
1975 | badly-written programs), but C<SIGPIPE> can cause spurious and rare |
|
|
1976 | program exits as a lot of people do not expect C<SIGPIPE> when writing to |
|
|
1977 | some random socket. |
|
|
1978 | |
|
|
1979 | The rationale for installing a no-op handler as opposed to ignoring it is |
|
|
1980 | that this way, the handler will be restored to defaults on exec. |
|
|
1981 | |
|
|
1982 | Feel free to install your own handler, or reset it to defaults. |
|
|
1983 | |
|
|
1984 | =back |
|
|
1985 | |
|
|
1986 | =cut |
|
|
1987 | |
|
|
1988 | $SIG{PIPE} = sub { } |
|
|
1989 | unless defined $SIG{PIPE}; |
1367 | |
1990 | |
1368 | |
1991 | |
1369 | =head1 FORK |
1992 | =head1 FORK |
1370 | |
1993 | |
1371 | Most event libraries are not fork-safe. The ones who are usually are |
1994 | Most event libraries are not fork-safe. The ones who are usually are |
… | |
… | |
1386 | specified in the variable. |
2009 | specified in the variable. |
1387 | |
2010 | |
1388 | You can make AnyEvent completely ignore this variable by deleting it |
2011 | You can make AnyEvent completely ignore this variable by deleting it |
1389 | before the first watcher gets created, e.g. with a C<BEGIN> block: |
2012 | before the first watcher gets created, e.g. with a C<BEGIN> block: |
1390 | |
2013 | |
1391 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
2014 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
1392 | |
2015 | |
1393 | use AnyEvent; |
2016 | use AnyEvent; |
1394 | |
2017 | |
1395 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
2018 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
1396 | be used to probe what backend is used and gain other information (which is |
2019 | be used to probe what backend is used and gain other information (which is |
1397 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL). |
2020 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and |
|
|
2021 | $ENV{PERL_ANYEVENT_STRICT}. |
|
|
2022 | |
|
|
2023 | |
|
|
2024 | =head1 BUGS |
|
|
2025 | |
|
|
2026 | Perl 5.8 has numerous memleaks that sometimes hit this module and are hard |
|
|
2027 | to work around. If you suffer from memleaks, first upgrade to Perl 5.10 |
|
|
2028 | and check wether the leaks still show up. (Perl 5.10.0 has other annoying |
|
|
2029 | memleaks, such as leaking on C<map> and C<grep> but it is usually not as |
|
|
2030 | pronounced). |
1398 | |
2031 | |
1399 | |
2032 | |
1400 | =head1 SEE ALSO |
2033 | =head1 SEE ALSO |
1401 | |
2034 | |
1402 | Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>, |
2035 | Utility functions: L<AnyEvent::Util>. |
1403 | L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>, |
2036 | |
|
|
2037 | Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, |
1404 | L<Event::Lib>, L<Qt>, L<POE>. |
2038 | L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. |
1405 | |
2039 | |
1406 | Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>, |
2040 | Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, |
1407 | L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, |
2041 | L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, |
1408 | L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>, |
2042 | L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, |
1409 | L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>. |
2043 | L<AnyEvent::Impl::POE>. |
1410 | |
2044 | |
|
|
2045 | Non-blocking file handles, sockets, TCP clients and |
|
|
2046 | servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. |
|
|
2047 | |
|
|
2048 | Asynchronous DNS: L<AnyEvent::DNS>. |
|
|
2049 | |
|
|
2050 | Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, |
|
|
2051 | |
1411 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. |
2052 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. |
1412 | |
2053 | |
1413 | |
2054 | |
1414 | =head1 AUTHOR |
2055 | =head1 AUTHOR |
1415 | |
2056 | |
1416 | Marc Lehmann <schmorp@schmorp.de> |
2057 | Marc Lehmann <schmorp@schmorp.de> |
1417 | http://home.schmorp.de/ |
2058 | http://home.schmorp.de/ |
1418 | |
2059 | |
1419 | =cut |
2060 | =cut |
1420 | |
2061 | |
1421 | 1 |
2062 | 1 |
1422 | |
2063 | |