| 1 | =head1 NAME |
1 | =head1 NAME |
| 2 | |
2 | |
| 3 | AnyEvent - provide framework for multiple event loops |
3 | AnyEvent - events independent of event loop implementation |
| 4 | |
4 | |
| 5 | EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported |
5 | EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported |
| 6 | event loops. |
6 | event loops. |
| 7 | |
7 | |
| 8 | =head1 SYNOPSIS |
8 | =head1 SYNOPSIS |
| … | |
… | |
| 40 | =head1 INTRODUCTION/TUTORIAL |
40 | =head1 INTRODUCTION/TUTORIAL |
| 41 | |
41 | |
| 42 | This manpage is mainly a reference manual. If you are interested |
42 | This manpage is mainly a reference manual. If you are interested |
| 43 | in a tutorial or some gentle introduction, have a look at the |
43 | in a tutorial or some gentle introduction, have a look at the |
| 44 | L<AnyEvent::Intro> manpage. |
44 | L<AnyEvent::Intro> manpage. |
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45 | |
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46 | =head1 SUPPORT |
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47 | |
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48 | There is a mailinglist for discussing all things AnyEvent, and an IRC |
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49 | channel, too. |
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50 | |
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51 | See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software |
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52 | Respository>, at L<http://anyevent.schmorp.de>, for more info. |
| 45 | |
53 | |
| 46 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
54 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
| 47 | |
55 | |
| 48 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
56 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
| 49 | nowadays. So what is different about AnyEvent? |
57 | nowadays. So what is different about AnyEvent? |
| … | |
… | |
| 368 | |
376 | |
| 369 | This watcher might use C<%SIG> (depending on the event loop used), |
377 | This watcher might use C<%SIG> (depending on the event loop used), |
| 370 | so programs overwriting those signals directly will likely not work |
378 | so programs overwriting those signals directly will likely not work |
| 371 | correctly. |
379 | correctly. |
| 372 | |
380 | |
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381 | Example: exit on SIGINT |
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382 | |
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383 | my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); |
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384 | |
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385 | =head3 Signal Races, Delays and Workarounds |
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386 | |
| 373 | Also note that many event loops (e.g. Glib, Tk, Qt, IO::Async) do not |
387 | Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching |
| 374 | support attaching callbacks to signals, which is a pity, as you cannot do |
388 | callbacks to signals in a generic way, which is a pity, as you cannot do |
| 375 | race-free signal handling in perl. AnyEvent will try to do it's best, but |
389 | race-free signal handling in perl. AnyEvent will try to do it's best, but |
| 376 | in some cases, signals will be delayed. The maximum time a signal might |
390 | in some cases, signals will be delayed. The maximum time a signal might |
| 377 | be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 |
391 | be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 |
| 378 | seconds). This variable can be changed only before the first signal |
392 | seconds). This variable can be changed only before the first signal |
| 379 | watcher is created, and should be left alone otherwise. Higher values |
393 | watcher is created, and should be left alone otherwise. Higher values |
| 380 | will cause fewer spurious wake-ups, which is better for power and CPU |
394 | will cause fewer spurious wake-ups, which is better for power and CPU |
| 381 | saving. All these problems can be avoided by installing the optional |
395 | saving. All these problems can be avoided by installing the optional |
| 382 | L<Async::Interrupt> module. |
396 | L<Async::Interrupt> module. This will not work with inherently broken |
| 383 | |
397 | event loops such as L<Event> or L<Event::Lib> (and not with L<POE> |
| 384 | Example: exit on SIGINT |
398 | currently, as POE does it's own workaround with one-second latency). With |
| 385 | |
399 | those, you just have to suffer the delays. |
| 386 | my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); |
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| 387 | |
400 | |
| 388 | =head2 CHILD PROCESS WATCHERS |
401 | =head2 CHILD PROCESS WATCHERS |
| 389 | |
402 | |
| 390 | You can also watch on a child process exit and catch its exit status. |
403 | You can also watch on a child process exit and catch its exit status. |
| 391 | |
404 | |
| … | |
… | |
| 504 | Condition variables are similar to callbacks, except that you can |
517 | Condition variables are similar to callbacks, except that you can |
| 505 | optionally wait for them. They can also be called merge points - points |
518 | optionally wait for them. They can also be called merge points - points |
| 506 | in time where multiple outstanding events have been processed. And yet |
519 | in time where multiple outstanding events have been processed. And yet |
| 507 | another way to call them is transactions - each condition variable can be |
520 | another way to call them is transactions - each condition variable can be |
| 508 | used to represent a transaction, which finishes at some point and delivers |
521 | used to represent a transaction, which finishes at some point and delivers |
| 509 | a result. |
522 | a result. And yet some people know them as "futures" - a promise to |
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523 | compute/deliver something that you can wait for. |
| 510 | |
524 | |
| 511 | Condition variables are very useful to signal that something has finished, |
525 | Condition variables are very useful to signal that something has finished, |
| 512 | for example, if you write a module that does asynchronous http requests, |
526 | for example, if you write a module that does asynchronous http requests, |
| 513 | then a condition variable would be the ideal candidate to signal the |
527 | then a condition variable would be the ideal candidate to signal the |
| 514 | availability of results. The user can either act when the callback is |
528 | availability of results. The user can either act when the callback is |
| … | |
… | |
| 1053 | |
1067 | |
| 1054 | BEGIN { AnyEvent::common_sense } |
1068 | BEGIN { AnyEvent::common_sense } |
| 1055 | |
1069 | |
| 1056 | use Carp (); |
1070 | use Carp (); |
| 1057 | |
1071 | |
| 1058 | our $VERSION = 4.83; |
1072 | our $VERSION = 4.86; |
| 1059 | our $MODEL; |
1073 | our $MODEL; |
| 1060 | |
1074 | |
| 1061 | our $AUTOLOAD; |
1075 | our $AUTOLOAD; |
| 1062 | our @ISA; |
1076 | our @ISA; |
| 1063 | |
1077 | |
| … | |
… | |
| 1270 | $_->() for values %{ $SIG_CB{$_} || {} }; |
1284 | $_->() for values %{ $SIG_CB{$_} || {} }; |
| 1271 | } |
1285 | } |
| 1272 | } |
1286 | } |
| 1273 | } |
1287 | } |
| 1274 | |
1288 | |
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1289 | # install a dumym wakeupw atcher to reduce signal catching latency |
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1290 | sub _sig_add() { |
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1291 | unless ($SIG_COUNT++) { |
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1292 | # try to align timer on a full-second boundary, if possible |
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1293 | my $NOW = AnyEvent->now; |
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1294 | |
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1295 | $SIG_TW = AnyEvent->timer ( |
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1296 | after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW), |
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1297 | interval => $MAX_SIGNAL_LATENCY, |
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1298 | cb => sub { }, # just for the PERL_ASYNC_CHECK |
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1299 | ); |
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1300 | } |
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1301 | } |
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1302 | |
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1303 | sub _sig_del { |
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1304 | undef $SIG_TW |
|
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1305 | unless --$SIG_COUNT; |
|
|
1306 | } |
|
|
1307 | |
| 1275 | sub _signal { |
1308 | sub _signal { |
| 1276 | my (undef, %arg) = @_; |
1309 | my (undef, %arg) = @_; |
| 1277 | |
1310 | |
| 1278 | my $signal = uc $arg{signal} |
1311 | my $signal = uc $arg{signal} |
| 1279 | or Carp::croak "required option 'signal' is missing"; |
1312 | or Carp::croak "required option 'signal' is missing"; |
| … | |
… | |
| 1303 | undef $SIG_EV{$signal}; |
1336 | undef $SIG_EV{$signal}; |
| 1304 | }; |
1337 | }; |
| 1305 | |
1338 | |
| 1306 | # can't do signal processing without introducing races in pure perl, |
1339 | # can't do signal processing without introducing races in pure perl, |
| 1307 | # so limit the signal latency. |
1340 | # so limit the signal latency. |
| 1308 | ++$SIG_COUNT; |
1341 | _sig_add; |
| 1309 | $SIG_TW ||= AnyEvent->timer ( |
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| 1310 | after => $MAX_SIGNAL_LATENCY, |
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| 1311 | interval => $MAX_SIGNAL_LATENCY, |
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| 1312 | cb => sub { }, # just for the PERL_ASYNC_CHECK |
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| 1313 | ); |
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|
| 1314 | } |
1342 | } |
| 1315 | |
1343 | |
| 1316 | bless [$signal, $arg{cb}], "AnyEvent::Base::signal" |
1344 | bless [$signal, $arg{cb}], "AnyEvent::Base::signal" |
| 1317 | } |
1345 | } |
| 1318 | |
1346 | |
| … | |
… | |
| 1357 | } |
1385 | } |
| 1358 | |
1386 | |
| 1359 | sub AnyEvent::Base::signal::DESTROY { |
1387 | sub AnyEvent::Base::signal::DESTROY { |
| 1360 | my ($signal, $cb) = @{$_[0]}; |
1388 | my ($signal, $cb) = @{$_[0]}; |
| 1361 | |
1389 | |
| 1362 | undef $SIG_TW |
1390 | _sig_del; |
| 1363 | unless --$SIG_COUNT; |
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| 1364 | |
1391 | |
| 1365 | delete $SIG_CB{$signal}{$cb}; |
1392 | delete $SIG_CB{$signal}{$cb}; |
| 1366 | |
1393 | |
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1394 | $HAVE_ASYNC_INTERRUPT |
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1395 | ? delete $SIG_ASY{$signal} |
| 1367 | # delete doesn't work with older perls - they then |
1396 | : # delete doesn't work with older perls - they then |
| 1368 | # print weird messages, or just unconditionally exit |
1397 | # print weird messages, or just unconditionally exit |
| 1369 | # instead of getting the default action. |
1398 | # instead of getting the default action. |
| 1370 | undef $SIG{$signal} |
1399 | undef $SIG{$signal} |
| 1371 | unless keys %{ $SIG_CB{$signal} }; |
1400 | unless keys %{ $SIG_CB{$signal} }; |
| 1372 | } |
1401 | } |
| 1373 | |
1402 | |
| 1374 | # default implementation for ->child |
1403 | # default implementation for ->child |
| 1375 | |
1404 | |
| … | |
… | |
| 2255 | |
2284 | |
| 2256 | This slightly arcane module is used to implement fast signal handling: To |
2285 | This slightly arcane module is used to implement fast signal handling: To |
| 2257 | my knowledge, there is no way to do completely race-free and quick |
2286 | my knowledge, there is no way to do completely race-free and quick |
| 2258 | signal handling in pure perl. To ensure that signals still get |
2287 | signal handling in pure perl. To ensure that signals still get |
| 2259 | delivered, AnyEvent will start an interval timer to wake up perl (and |
2288 | delivered, AnyEvent will start an interval timer to wake up perl (and |
| 2260 | catch the signals) with soemd elay (default is 10 seconds, look for |
2289 | catch the signals) with some delay (default is 10 seconds, look for |
| 2261 | C<$AnyEvent::MAX_SIGNAL_LATENCY>). |
2290 | C<$AnyEvent::MAX_SIGNAL_LATENCY>). |
| 2262 | |
2291 | |
| 2263 | If this module is available, then it will be used to implement signal |
2292 | If this module is available, then it will be used to implement signal |
| 2264 | catching, which means that signals will not be delayed, and the event loop |
2293 | catching, which means that signals will not be delayed, and the event loop |
| 2265 | will not be interrupted regularly, which is more efficient (And good for |
2294 | will not be interrupted regularly, which is more efficient (And good for |
| 2266 | battery life on laptops). |
2295 | battery life on laptops). |
| 2267 | |
2296 | |
| 2268 | This affects not just the pure-perl event loop, but also other event loops |
2297 | This affects not just the pure-perl event loop, but also other event loops |
| 2269 | that have no signal handling on their own (e.g. Glib, Tk, Qt). |
2298 | that have no signal handling on their own (e.g. Glib, Tk, Qt). |
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2299 | |
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2300 | Some event loops (POE, Event, Event::Lib) offer signal watchers natively, |
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2301 | and either employ their own workarounds (POE) or use AnyEvent's workaround |
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2302 | (using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt> |
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2303 | does nothing for those backends. |
| 2270 | |
2304 | |
| 2271 | =item L<EV> |
2305 | =item L<EV> |
| 2272 | |
2306 | |
| 2273 | This module isn't really "optional", as it is simply one of the backend |
2307 | This module isn't really "optional", as it is simply one of the backend |
| 2274 | event loops that AnyEvent can use. However, it is simply the best event |
2308 | event loops that AnyEvent can use. However, it is simply the best event |
| … | |
… | |
| 2288 | |
2322 | |
| 2289 | =item L<JSON> and L<JSON::XS> |
2323 | =item L<JSON> and L<JSON::XS> |
| 2290 | |
2324 | |
| 2291 | This module is required when you want to read or write JSON data via |
2325 | This module is required when you want to read or write JSON data via |
| 2292 | L<AnyEvent::Handle>. It is also written in pure-perl, but can take |
2326 | L<AnyEvent::Handle>. It is also written in pure-perl, but can take |
| 2293 | advantage of the ulta-high-speed L<JSON::XS> module when it is installed. |
2327 | advantage of the ultra-high-speed L<JSON::XS> module when it is installed. |
| 2294 | |
2328 | |
| 2295 | In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is |
2329 | In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is |
| 2296 | installed. |
2330 | installed. |
| 2297 | |
2331 | |
| 2298 | =item L<Net::SSLeay> |
2332 | =item L<Net::SSLeay> |
