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Revision 1.69 by root, Tue Oct 4 17:45:04 2011 UTC vs.
Revision 1.71 by root, Wed Aug 21 08:40:28 2013 UTC

262 262
263 Example 2: fire an event after 0.5 seconds, then roughly every second. 263 Example 2: fire an event after 0.5 seconds, then roughly every second.
264 264
265 my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub { 265 my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
266 warn "timeout\n"; 266 warn "timeout\n";
267 }; 267 });
268 268
269 TIMING ISSUES 269 TIMING ISSUES
270 There are two ways to handle timers: based on real time (relative, "fire 270 There are two ways to handle timers: based on real time (relative, "fire
271 in 10 seconds") and based on wallclock time (absolute, "fire at 12 271 in 10 seconds") and based on wallclock time (absolute, "fire at 12
272 o'clock"). 272 o'clock").
419 race-free signal handling in perl, requiring C libraries for this. 419 race-free signal handling in perl, requiring C libraries for this.
420 AnyEvent will try to do its best, which means in some cases, signals 420 AnyEvent will try to do its best, which means in some cases, signals
421 will be delayed. The maximum time a signal might be delayed is 10 421 will be delayed. The maximum time a signal might be delayed is 10
422 seconds by default, but can be overriden via 422 seconds by default, but can be overriden via
423 $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} or $AnyEvent::MAX_SIGNAL_LATENCY 423 $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} or $AnyEvent::MAX_SIGNAL_LATENCY
424 - see the Ö<ENVIRONMENT VARIABLES> section for details. 424 - see the "ENVIRONMENT VARIABLES" section for details.
425 425
426 All these problems can be avoided by installing the optional 426 All these problems can be avoided by installing the optional
427 Async::Interrupt module, which works with most event loops. It will not 427 Async::Interrupt module, which works with most event loops. It will not
428 work with inherently broken event loops such as Event or Event::Lib (and 428 work with inherently broken event loops such as Event or Event::Lib (and
429 not with POE currently). For those, you just have to suffer the delays. 429 not with POE currently). For those, you just have to suffer the delays.
736 }; 736 };
737 } 737 }
738 738
739 $cv->end; 739 $cv->end;
740 740
741 ...
742
743 my $results = $cv->recv;
744
741 This code fragment supposedly pings a number of hosts and calls 745 This code fragment supposedly pings a number of hosts and calls
742 "send" after results for all then have have been gathered - in any 746 "send" after results for all then have have been gathered - in any
743 order. To achieve this, the code issues a call to "begin" when it 747 order. To achieve this, the code issues a call to "begin" when it
744 starts each ping request and calls "end" when it has received some 748 starts each ping request and calls "end" when it has received some
745 result for it. Since "begin" and "end" only maintain a counter, the 749 result for it. Since "begin" and "end" only maintain a counter, the
774 In list context, all parameters passed to "send" will be returned, 778 In list context, all parameters passed to "send" will be returned,
775 in scalar context only the first one will be returned. 779 in scalar context only the first one will be returned.
776 780
777 Note that doing a blocking wait in a callback is not supported by 781 Note that doing a blocking wait in a callback is not supported by
778 any event loop, that is, recursive invocation of a blocking "->recv" 782 any event loop, that is, recursive invocation of a blocking "->recv"
779 is not allowed, and the "recv" call will "croak" if such a condition 783 is not allowed and the "recv" call will "croak" if such a condition
780 is detected. This condition can be slightly loosened by using 784 is detected. This requirement can be dropped by relying on
781 Coro::AnyEvent, which allows you to do a blocking "->recv" from any 785 Coro::AnyEvent , which allows you to do a blocking "->recv" from any
782 thread that doesn't run the event loop itself. 786 thread that doesn't run the event loop itself. Coro::AnyEvent is
787 loaded automatically when Coro is used with AnyEvent, so code does
788 not need to do anything special to take advantage of that: any code
789 that would normally block your program because it calls "recv", be
790 executed in an "async" thread instead without blocking other
791 threads.
783 792
784 Not all event models support a blocking wait - some die in that case 793 Not all event models support a blocking wait - some die in that case
785 (programs might want to do that to stay interactive), so *if you are 794 (programs might want to do that to stay interactive), so *if you are
786 using this from a module, never require a blocking wait*. Instead, 795 using this from a module, never require a blocking wait*. Instead,
787 let the caller decide whether the call will block or not (for 796 let the caller decide whether the call will block or not (for
1082 modules come as part of AnyEvent, the others are available via CPAN (see 1091 modules come as part of AnyEvent, the others are available via CPAN (see
1083 <http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for a longer 1092 <http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for a longer
1084 non-exhaustive list), and the list is heavily biased towards modules of 1093 non-exhaustive list), and the list is heavily biased towards modules of
1085 the AnyEvent author himself :) 1094 the AnyEvent author himself :)
1086 1095
1087 AnyEvent::Util 1096 AnyEvent::Util (part of the AnyEvent distribution)
1088 Contains various utility functions that replace often-used blocking 1097 Contains various utility functions that replace often-used blocking
1089 functions such as "inet_aton" with event/callback-based versions. 1098 functions such as "inet_aton" with event/callback-based versions.
1090 1099
1091 AnyEvent::Socket 1100 AnyEvent::Socket (part of the AnyEvent distribution)
1092 Provides various utility functions for (internet protocol) sockets, 1101 Provides various utility functions for (internet protocol) sockets,
1093 addresses and name resolution. Also functions to create non-blocking 1102 addresses and name resolution. Also functions to create non-blocking
1094 tcp connections or tcp servers, with IPv6 and SRV record support and 1103 tcp connections or tcp servers, with IPv6 and SRV record support and
1095 more. 1104 more.
1096 1105
1097 AnyEvent::Handle 1106 AnyEvent::Handle (part of the AnyEvent distribution)
1098 Provide read and write buffers, manages watchers for reads and 1107 Provide read and write buffers, manages watchers for reads and
1099 writes, supports raw and formatted I/O, I/O queued and fully 1108 writes, supports raw and formatted I/O, I/O queued and fully
1100 transparent and non-blocking SSL/TLS (via AnyEvent::TLS). 1109 transparent and non-blocking SSL/TLS (via AnyEvent::TLS).
1101 1110
1102 AnyEvent::DNS 1111 AnyEvent::DNS (part of the AnyEvent distribution)
1103 Provides rich asynchronous DNS resolver capabilities. 1112 Provides rich asynchronous DNS resolver capabilities.
1104 1113
1105 AnyEvent::HTTP, AnyEvent::IRC, AnyEvent::XMPP, AnyEvent::GPSD, 1114 AnyEvent::HTTP, AnyEvent::IRC, AnyEvent::XMPP, AnyEvent::GPSD,
1106 AnyEvent::IGS, AnyEvent::FCP 1115 AnyEvent::IGS, AnyEvent::FCP
1107 Implement event-based interfaces to the protocols of the same name 1116 Implement event-based interfaces to the protocols of the same name
1108 (for the curious, IGS is the International Go Server and FCP is the 1117 (for the curious, IGS is the International Go Server and FCP is the
1109 Freenet Client Protocol). 1118 Freenet Client Protocol).
1110 1119
1111 AnyEvent::AIO 1120 AnyEvent::AIO (part of the AnyEvent distribution)
1112 Truly asynchronous (as opposed to non-blocking) I/O, should be in 1121 Truly asynchronous (as opposed to non-blocking) I/O, should be in
1113 the toolbox of every event programmer. AnyEvent::AIO transparently 1122 the toolbox of every event programmer. AnyEvent::AIO transparently
1114 fuses IO::AIO and AnyEvent together, giving AnyEvent access to 1123 fuses IO::AIO and AnyEvent together, giving AnyEvent access to
1115 event-based file I/O, and much more. 1124 event-based file I/O, and much more.
1116 1125
1214 This ensures that child processes will not see the "AE_" variables. 1223 This ensures that child processes will not see the "AE_" variables.
1215 1224
1216 The following environment variables are currently known to AnyEvent: 1225 The following environment variables are currently known to AnyEvent:
1217 1226
1218 "PERL_ANYEVENT_VERBOSE" 1227 "PERL_ANYEVENT_VERBOSE"
1219 By default, AnyEvent will only log messages with loglevel 3 1228 By default, AnyEvent will log messages with loglevel 4 ("error") or
1220 ("critical") or higher (see AnyEvent::Log). You can set this 1229 higher (see AnyEvent::Log). You can set this environment variable to
1221 environment variable to a numerical loglevel to make AnyEvent more 1230 a numerical loglevel to make AnyEvent more (or less) talkative.
1222 (or less) talkative.
1223 1231
1224 If you want to do more than just set the global logging level you 1232 If you want to do more than just set the global logging level you
1225 should have a look at "PERL_ANYEVENT_LOG", which allows much more 1233 should have a look at "PERL_ANYEVENT_LOG", which allows much more
1226 complex specifications. 1234 complex specifications.
1227 1235
1228 When set to 0 ("off"), then no messages whatsoever will be logged 1236 When set to 0 ("off"), then no messages whatsoever will be logged
1229 with the default logging settings. 1237 with everything else at defaults.
1230 1238
1231 When set to 5 or higher ("warn"), causes AnyEvent to warn about 1239 When set to 5 or higher ("warn"), AnyEvent warns about unexpected
1232 unexpected conditions, such as not being able to load the event 1240 conditions, such as not being able to load the event model specified
1233 model specified by "PERL_ANYEVENT_MODEL", or a guard callback 1241 by "PERL_ANYEVENT_MODEL", or a guard callback throwing an exception
1234 throwing an exception - this is the minimum recommended level. 1242 - this is the minimum recommended level for use during development.
1235 1243
1236 When set to 7 or higher (info), cause AnyEvent to report which event 1244 When set to 7 or higher (info), AnyEvent reports which event model
1237 model it chooses. 1245 it chooses.
1238 1246
1239 When set to 8 or higher (debug), then AnyEvent will report extra 1247 When set to 8 or higher (debug), then AnyEvent will report extra
1240 information on which optional modules it loads and how it implements 1248 information on which optional modules it loads and how it implements
1241 certain features. 1249 certain features.
1242 1250
1254 itself. 1262 itself.
1255 1263
1256 Note that specifying this environment variable causes the 1264 Note that specifying this environment variable causes the
1257 AnyEvent::Log module to be loaded, while "PERL_ANYEVENT_VERBOSE" 1265 AnyEvent::Log module to be loaded, while "PERL_ANYEVENT_VERBOSE"
1258 does not, so only using the latter saves a few hundred kB of memory 1266 does not, so only using the latter saves a few hundred kB of memory
1259 until the first message is being logged. 1267 unless a module explicitly needs the extra features of
1268 AnyEvent::Log.
1260 1269
1261 "PERL_ANYEVENT_STRICT" 1270 "PERL_ANYEVENT_STRICT"
1262 AnyEvent does not do much argument checking by default, as thorough 1271 AnyEvent does not do much argument checking by default, as thorough
1263 argument checking is very costly. Setting this variable to a true 1272 argument checking is very costly. Setting this variable to a true
1264 value will cause AnyEvent to load "AnyEvent::Strict" and then to 1273 value will cause AnyEvent to load "AnyEvent::Strict" and then to
1316 1325
1317 For example, to force the pure perl model (AnyEvent::Loop::Perl) you 1326 For example, to force the pure perl model (AnyEvent::Loop::Perl) you
1318 could start your program like this: 1327 could start your program like this:
1319 1328
1320 PERL_ANYEVENT_MODEL=Perl perl ... 1329 PERL_ANYEVENT_MODEL=Perl perl ...
1330
1331 "PERL_ANYEVENT_IO_MODEL"
1332 The current file I/O model - see AnyEvent::IO for more info.
1333
1334 At the moment, only "Perl" (small, pure-perl, synchronous) and
1335 "IOAIO" (truly asynchronous) are supported. The default is "IOAIO"
1336 if AnyEvent::AIO can be loaded, otherwise it is "Perl".
1321 1337
1322 "PERL_ANYEVENT_PROTOCOLS" 1338 "PERL_ANYEVENT_PROTOCOLS"
1323 Used by both AnyEvent::DNS and AnyEvent::Socket to determine 1339 Used by both AnyEvent::DNS and AnyEvent::Socket to determine
1324 preferences for IPv4 or IPv6. The default is unspecified (and might 1340 preferences for IPv4 or IPv6. The default is unspecified (and might
1325 change, or be the result of auto probing). 1341 change, or be the result of auto probing).
1994 This module is part of perl since release 5.008. It will be used 2010 This module is part of perl since release 5.008. It will be used
1995 when the chosen event library does not come with a timing source of 2011 when the chosen event library does not come with a timing source of
1996 its own. The pure-perl event loop (AnyEvent::Loop) will additionally 2012 its own. The pure-perl event loop (AnyEvent::Loop) will additionally
1997 load it to try to use a monotonic clock for timing stability. 2013 load it to try to use a monotonic clock for timing stability.
1998 2014
2015 AnyEvent::AIO (and IO::AIO)
2016 The default implementation of AnyEvent::IO is to do I/O
2017 synchronously, stopping programs while they access the disk, which
2018 is fine for a lot of programs.
2019
2020 Installing AnyEvent::AIO (and its IO::AIO dependency) makes it
2021 switch to a true asynchronous implementation, so event processing
2022 can continue even while waiting for disk I/O.
2023
1999FORK 2024FORK
2000 Most event libraries are not fork-safe. The ones who are usually are 2025 Most event libraries are not fork-safe. The ones who are usually are
2001 because they rely on inefficient but fork-safe "select" or "poll" calls 2026 because they rely on inefficient but fork-safe "select" or "poll" calls
2002 - higher performance APIs such as BSD's kqueue or the dreaded Linux 2027 - higher performance APIs such as BSD's kqueue or the dreaded Linux
2003 epoll are usually badly thought-out hacks that are incompatible with 2028 epoll are usually badly thought-out hacks that are incompatible with
2074 AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi, AnyEvent::Impl::FLTK. 2099 AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi, AnyEvent::Impl::FLTK.
2075 2100
2076 Non-blocking handles, pipes, stream sockets, TCP clients and servers: 2101 Non-blocking handles, pipes, stream sockets, TCP clients and servers:
2077 AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS. 2102 AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS.
2078 2103
2104 Asynchronous File I/O: AnyEvent::IO.
2105
2079 Asynchronous DNS: AnyEvent::DNS. 2106 Asynchronous DNS: AnyEvent::DNS.
2080 2107
2081 Thread support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event. 2108 Thread support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event.
2082 2109
2083 Nontrivial usage examples: AnyEvent::GPSD, AnyEvent::IRC, 2110 Nontrivial usage examples: AnyEvent::GPSD, AnyEvent::IRC,
2084 AnyEvent::HTTP. 2111 AnyEvent::HTTP.
2085 2112
2086AUTHOR 2113AUTHOR
2087 Marc Lehmann <schmorp@schmorp.de> 2114 Marc Lehmann <schmorp@schmorp.de>
2088 http://home.schmorp.de/ 2115 http://anyevent.schmorp.de
2089 2116

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