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2 | AnyEvent - provide framework for multiple event loops |
2 | AnyEvent - provide framework for multiple event loops |
3 | |
3 | |
4 | Event, Coro, Glib, Tk - various supported event loops |
4 | Event, Coro, Glib, Tk - various supported event loops |
5 | |
5 | |
6 | SYNOPSIS |
6 | SYNOPSIS |
7 | use AnyEvent; |
7 | use AnyEvent; |
8 | |
8 | |
9 | my $w = AnyEvent->io (fh => ..., poll => "[rw]+", cb => sub { |
9 | my $w = AnyEvent->io (fh => ..., poll => "[rw]+", cb => sub { |
10 | my ($poll_got) = @_; |
10 | my ($poll_got) = @_; |
11 | ... |
11 | ... |
12 | }); |
12 | }); |
13 | |
13 | |
14 | - only one io watcher per $fh and $poll type is allowed (i.e. on a |
14 | * only one io watcher per $fh and $poll type is allowed (i.e. on a |
15 | socket you can have one r + one w or one rw watcher, not any more. |
15 | socket you can have one r + one w or one rw watcher, not any more |
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16 | (limitation by Tk). |
16 | |
17 | |
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18 | * the $poll_got passed to the handler needs to be checked by looking for |
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19 | single characters (e.g. with a regex), as it can contain more event |
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20 | types than were requested (e.g. a 'w' watcher might generate 'rw' |
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21 | events, limitation by Glib). |
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22 | |
17 | - AnyEvent will keep filehandles alive, so as long as the watcher |
23 | * AnyEvent will keep filehandles alive, so as long as the watcher |
18 | exists, the filehandle exists. |
24 | exists, the filehandle exists. |
19 | |
25 | |
20 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
26 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
21 | ... |
27 | ... |
22 | }); |
28 | }); |
23 | |
29 | |
24 | - io and time watchers get canceled whenever $w is destroyed, so keep a |
30 | * io and time watchers get canceled whenever $w is destroyed, so keep a |
25 | copy |
31 | copy |
26 | |
32 | |
27 | - timers can only be used once and must be recreated for repeated |
33 | * timers can only be used once and must be recreated for repeated |
28 | operation |
34 | operation (limitation by Glib and Tk). |
29 | |
35 | |
30 | my $w = AnyEvent->condvar; # kind of main loop replacement |
36 | my $w = AnyEvent->condvar; # kind of main loop replacement |
31 | $w->wait; # enters main loop till $condvar gets ->broadcast |
37 | $w->wait; # enters main loop till $condvar gets ->broadcast |
32 | $w->broadcast; # wake up current and all future wait's |
38 | $w->broadcast; # wake up current and all future wait's |
33 | |
39 | |
34 | - condvars are used to give blocking behaviour when neccessary. Create a |
40 | * condvars are used to give blocking behaviour when neccessary. Create a |
35 | condvar for any "request" or "event" your module might create, |
41 | condvar for any "request" or "event" your module might create, |
36 | "->broadcast" it when the event happens and provide a function that |
42 | "->broadcast" it when the event happens and provide a function that |
37 | calls "->wait" for it. See the examples below. |
43 | calls "->wait" for it. See the examples below. |
38 | |
44 | |
39 | DESCRIPTION |
45 | DESCRIPTION |
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50 | modules is loaded: Coro::Event, Event, Glib, Tk. The first one found is |
56 | modules is loaded: Coro::Event, Event, Glib, Tk. The first one found is |
51 | used. If none is found, the module tries to load these modules in the |
57 | used. If none is found, the module tries to load these modules in the |
52 | order given. The first one that could be successfully loaded will be |
58 | order given. The first one that could be successfully loaded will be |
53 | used. If still none could be found, it will issue an error. |
59 | used. If still none could be found, it will issue an error. |
54 | |
60 | |
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61 | ENVIRONMENT VARIABLES |
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62 | The following environment variables are used by this module: |
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63 | |
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64 | "PERL_ANYEVENT_VERBOSE" when set to 2 or higher, reports which event |
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65 | model gets used. |
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66 | |
55 | EXAMPLE |
67 | EXAMPLE |
56 | The following program uses an io watcher to read data from stdin, a |
68 | The following program uses an io watcher to read data from stdin, a |
57 | timer to display a message once per second, and a condvar to exit the |
69 | timer to display a message once per second, and a condvar to exit the |
58 | program when the user enters quit: |
70 | program when the user enters quit: |
59 | |
71 | |
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116 | connect $txn->{fh}, ... |
128 | connect $txn->{fh}, ... |
117 | and !$!{EWOULDBLOCK} |
129 | and !$!{EWOULDBLOCK} |
118 | and !$!{EINPROGRESS} |
130 | and !$!{EINPROGRESS} |
119 | and Carp::croak "unable to connect: $!\n"; |
131 | and Carp::croak "unable to connect: $!\n"; |
120 | |
132 | |
121 | Then it creates a write-watcher which gets called wehnever an error |
133 | Then it creates a write-watcher which gets called whenever an error |
122 | occurs or the connection succeeds: |
134 | occurs or the connection succeeds: |
123 | |
135 | |
124 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'w', cb => sub { $txn->fh_ready_w }); |
136 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'w', cb => sub { $txn->fh_ready_w }); |
125 | |
137 | |
126 | And returns this transaction object. The "fh_ready_w" callback gets |
138 | And returns this transaction object. The "fh_ready_w" callback gets |
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143 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
155 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
144 | |
156 | |
145 | if (end-of-file or data complete) { |
157 | if (end-of-file or data complete) { |
146 | $txn->{result} = $txn->{buf}; |
158 | $txn->{result} = $txn->{buf}; |
147 | $txn->{finished}->broadcast; |
159 | $txn->{finished}->broadcast; |
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160 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
148 | } |
161 | } |
149 | |
162 | |
150 | The "result" method, finally, just waits for the finished signal (if the |
163 | The "result" method, finally, just waits for the finished signal (if the |
151 | request was already finished, it doesn't wait, of course, and returns |
164 | request was already finished, it doesn't wait, of course, and returns |
152 | the data: |
165 | the data: |
153 | |
166 | |
154 | $txn->{finished}->wait; |
167 | $txn->{finished}->wait; |
155 | return $txn->{buf}; |
168 | return $txn->{result}; |
156 | |
169 | |
157 | The actual code goes further and collects all errors ("die"s, |
170 | The actual code goes further and collects all errors ("die"s, |
158 | exceptions) that occured during request processing. The "result" method |
171 | exceptions) that occured during request processing. The "result" method |
159 | detects wether an exception as thrown (it is stored inside the $txn |
172 | detects wether an exception as thrown (it is stored inside the $txn |
160 | object) and just throws the exception, which means connection errors and |
173 | object) and just throws the exception, which means connection errors and |