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Revision 1.65 by root, Sat Aug 13 22:44:05 2011 UTC vs.
Revision 1.67 by root, Fri Aug 26 05:33:53 2011 UTC

1NAME 1NAME
2 AnyEvent - the DBI of event loop programming 2 AnyEvent - the DBI of event loop programming
3 3
4 EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, 4 EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async,
5 Qt and POE are various supported event loops/environments. 5 Qt, FLTK and POE are various supported event loops/environments.
6 6
7SYNOPSIS 7SYNOPSIS
8 use AnyEvent; 8 use AnyEvent;
9 9
10 # if you prefer function calls, look at the AE manpage for 10 # if you prefer function calls, look at the AE manpage for
1002 It should use "postpone": 1002 It should use "postpone":
1003 1003
1004 AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later 1004 AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
1005 if $some_error_condition; 1005 if $some_error_condition;
1006 1006
1007 AnyEvent::log $level, $msg[, @args]
1008 Log the given $msg at the given $level.
1009
1010 If AnyEvent::Log is not loaded then this function makes a simple
1011 test to see whether the message will be logged. If the test succeeds
1012 it will load AnyEvent::Log and call "AnyEvent::Log::log" -
1013 consequently, look at the AnyEvent::Log documentation for details.
1014
1015 If the test fails it will simply return.
1016
1017 If you want to sprinkle loads of logging calls around your code,
1018 consider creating a logger callback with the "AnyEvent::Log::logger"
1019 function, which can reduce typing, codesize and can reduce the
1020 logging overhead enourmously.
1021
1007WHAT TO DO IN A MODULE 1022WHAT TO DO IN A MODULE
1008 As a module author, you should "use AnyEvent" and call AnyEvent methods 1023 As a module author, you should "use AnyEvent" and call AnyEvent methods
1009 freely, but you should not load a specific event module or rely on it. 1024 freely, but you should not load a specific event module or rely on it.
1010 1025
1011 Be careful when you create watchers in the module body - AnyEvent will 1026 Be careful when you create watchers in the module body - AnyEvent will
1064 1079
1065OTHER MODULES 1080OTHER MODULES
1066 The following is a non-exhaustive list of additional modules that use 1081 The following is a non-exhaustive list of additional modules that use
1067 AnyEvent as a client and can therefore be mixed easily with other 1082 AnyEvent as a client and can therefore be mixed easily with other
1068 AnyEvent modules and other event loops in the same program. Some of the 1083 AnyEvent modules and other event loops in the same program. Some of the
1069 modules come as part of AnyEvent, the others are available via CPAN. 1084 modules come as part of AnyEvent, the others are available via CPAN (see
1085 <http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for a longer
1086 non-exhaustive list), and the list is heavily biased towards modules of
1087 the AnyEvent author himself :)
1070 1088
1071 AnyEvent::Util 1089 AnyEvent::Util
1072 Contains various utility functions that replace often-used blocking 1090 Contains various utility functions that replace often-used blocking
1073 functions such as "inet_aton" with event/callback-based versions. 1091 functions such as "inet_aton" with event/callback-based versions.
1074 1092
1090 AnyEvent::IGS, AnyEvent::FCP 1108 AnyEvent::IGS, AnyEvent::FCP
1091 Implement event-based interfaces to the protocols of the same name 1109 Implement event-based interfaces to the protocols of the same name
1092 (for the curious, IGS is the International Go Server and FCP is the 1110 (for the curious, IGS is the International Go Server and FCP is the
1093 Freenet Client Protocol). 1111 Freenet Client Protocol).
1094 1112
1095 AnyEvent::Handle::UDP
1096 Here be danger!
1097
1098 As Pauli would put it, "Not only is it not right, it's not even
1099 wrong!" - there are so many things wrong with AnyEvent::Handle::UDP,
1100 most notably its use of a stream-based API with a protocol that
1101 isn't streamable, that the only way to improve it is to delete it.
1102
1103 It features data corruption (but typically only under load) and
1104 general confusion. On top, the author is not only clueless about UDP
1105 but also fact-resistant - some gems of his understanding: "connect
1106 doesn't work with UDP", "UDP packets are not IP packets", "UDP only
1107 has datagrams, not packets", "I don't need to implement proper error
1108 checking as UDP doesn't support error checking" and so on - he
1109 doesn't even understand what's wrong with his module when it is
1110 explained to him.
1111
1112 AnyEvent::DBI
1113 Executes DBI requests asynchronously in a proxy process for you,
1114 notifying you in an event-based way when the operation is finished.
1115
1116 AnyEvent::AIO 1113 AnyEvent::AIO
1117 Truly asynchronous (as opposed to non-blocking) I/O, should be in 1114 Truly asynchronous (as opposed to non-blocking) I/O, should be in
1118 the toolbox of every event programmer. AnyEvent::AIO transparently 1115 the toolbox of every event programmer. AnyEvent::AIO transparently
1119 fuses IO::AIO and AnyEvent together, giving AnyEvent access to 1116 fuses IO::AIO and AnyEvent together, giving AnyEvent access to
1120 event-based file I/O, and much more. 1117 event-based file I/O, and much more.
1121 1118
1119 AnyEvent::Filesys::Notify
1120 AnyEvent is good for non-blocking stuff, but it can't detect file or
1121 path changes (e.g. "watch this directory for new files", "watch this
1122 file for changes"). The AnyEvent::Filesys::Notify module promises to
1123 do just that in a portbale fashion, supporting inotify on GNU/Linux
1124 and some weird, without doubt broken, stuff on OS X to monitor
1125 files. It can fall back to blocking scans at regular intervals
1126 transparently on other platforms, so it's about as portable as it
1127 gets.
1128
1129 (I haven't used it myself, but I haven't heard anybody complaining
1130 about it yet).
1131
1132 AnyEvent::DBI
1133 Executes DBI requests asynchronously in a proxy process for you,
1134 notifying you in an event-based way when the operation is finished.
1135
1122 AnyEvent::HTTPD 1136 AnyEvent::HTTPD
1123 A simple embedded webserver. 1137 A simple embedded webserver.
1124 1138
1125 AnyEvent::FastPing 1139 AnyEvent::FastPing
1126 The fastest ping in the west. 1140 The fastest ping in the west.
1127 1141
1128 Coro 1142 Coro
1129 Has special support for AnyEvent via Coro::AnyEvent. 1143 Has special support for AnyEvent via Coro::AnyEvent, which allows
1144 you to simply invert the flow control - don't call us, we will call
1145 you:
1146
1147 async {
1148 Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
1149 print "5 seconds later!\n";
1150
1151 Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
1152 my $line = <STDIN>; # works for ttys
1153
1154 AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
1155 my ($body, $hdr) = Coro::rouse_wait;
1156 };
1130 1157
1131SIMPLIFIED AE API 1158SIMPLIFIED AE API
1132 Starting with version 5.0, AnyEvent officially supports a second, much 1159 Starting with version 5.0, AnyEvent officially supports a second, much
1133 simpler, API that is designed to reduce the calling, typing and memory 1160 simpler, API that is designed to reduce the calling, typing and memory
1134 overhead by using function call syntax and a fixed number of parameters. 1161 overhead by using function call syntax and a fixed number of parameters.
1150 The pure perl event loop simply re-throws the exception (usually within 1177 The pure perl event loop simply re-throws the exception (usually within
1151 "condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()", 1178 "condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()",
1152 Glib uses "install_exception_handler" and so on. 1179 Glib uses "install_exception_handler" and so on.
1153 1180
1154ENVIRONMENT VARIABLES 1181ENVIRONMENT VARIABLES
1155 The following environment variables are used by this module or its 1182 AnyEvent supports a number of environment variables that tune the
1156 submodules. 1183 runtime behaviour. They are usually evaluated when AnyEvent is loaded,
1184 initialised, or a submodule that uses them is loaded. Many of them also
1185 cause AnyEvent to load additional modules - for example,
1186 "PERL_ANYEVENT_DEBUG_WRAP" causes the AnyEvent::Debug module to be
1187 loaded.
1157 1188
1158 Note that AnyEvent will remove *all* environment variables starting with 1189 All the environment variables documented here start with
1159 "PERL_ANYEVENT_" from %ENV when it is loaded while taint mode is 1190 "PERL_ANYEVENT_", which is what AnyEvent considers its own namespace.
1160 enabled. 1191 Other modules are encouraged (but by no means required) to use
1192 "PERL_ANYEVENT_SUBMODULE" if they have registered the
1193 AnyEvent::Submodule namespace on CPAN, for any submodule. For example,
1194 AnyEvent::HTTP could be expected to use "PERL_ANYEVENT_HTTP_PROXY" (it
1195 should not access env variables starting with "AE_", see below).
1196
1197 All variables can also be set via the "AE_" prefix, that is, instead of
1198 setting "PERL_ANYEVENT_VERBOSE" you can also set "AE_VERBOSE". In case
1199 there is a clash btween anyevent and another program that uses
1200 "AE_something" you can set the corresponding "PERL_ANYEVENT_something"
1201 variable to the empty string, as those variables take precedence.
1202
1203 When AnyEvent is first loaded, it copies all "AE_xxx" env variables to
1204 their "PERL_ANYEVENT_xxx" counterpart unless that variable already
1205 exists. If taint mode is on, then AnyEvent will remove *all* environment
1206 variables starting with "PERL_ANYEVENT_" from %ENV (or replace them with
1207 "undef" or the empty string, if the corresaponding "AE_" variable is
1208 set).
1209
1210 The exact algorithm is currently:
1211
1212 1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
1213 2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
1214 3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
1215
1216 This ensures that child processes will not see the "AE_" variables.
1217
1218 The following environment variables are currently known to AnyEvent:
1161 1219
1162 "PERL_ANYEVENT_VERBOSE" 1220 "PERL_ANYEVENT_VERBOSE"
1163 By default, AnyEvent will be completely silent except in fatal 1221 By default, AnyEvent will be completely silent except in fatal
1164 conditions. You can set this environment variable to make AnyEvent 1222 conditions. You can set this environment variable to make AnyEvent
1165 more talkative. 1223 more talkative. If you want to do more than just set the global
1224 logging level you should have a look at "PERL_ANYEVENT_LOG", which
1225 allows much more complex specifications.
1166 1226
1167 When set to 1 or higher, causes AnyEvent to warn about unexpected 1227 When set to 5 or higher (warn), causes AnyEvent to warn about
1168 conditions, such as not being able to load the event model specified 1228 unexpected conditions, such as not being able to load the event
1169 by "PERL_ANYEVENT_MODEL". 1229 model specified by "PERL_ANYEVENT_MODEL", or a guard callback
1230 throwing an exception - this is the minimum recommended level.
1170 1231
1171 When set to 2 or higher, cause AnyEvent to report to STDERR which 1232 When set to 7 or higher (info), cause AnyEvent to report which event
1172 event model it chooses. 1233 model it chooses.
1173 1234
1174 When set to 8 or higher, then AnyEvent will report extra information 1235 When set to 8 or higher (debug), then AnyEvent will report extra
1175 on which optional modules it loads and how it implements certain 1236 information on which optional modules it loads and how it implements
1176 features. 1237 certain features.
1238
1239 "PERL_ANYEVENT_LOG"
1240 Accepts rather complex logging specifications. For example, you
1241 could log all "debug" messages of some module to stderr, warnings
1242 and above to stderr, and errors and above to syslog, with:
1243
1244 PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
1245
1246 For the rather extensive details, see AnyEvent::Log.
1247
1248 This variable is evaluated when AnyEvent (or AnyEvent::Log) is
1249 loaded, so will take effect even before AnyEvent has initialised
1250 itself.
1251
1252 Note that specifying this environment variable causes the
1253 AnyEvent::Log module to be loaded, while "PERL_ANYEVENT_VERBOSE"
1254 does not, so only using the latter saves a few hundred kB of memory
1255 until the first message is being logged.
1177 1256
1178 "PERL_ANYEVENT_STRICT" 1257 "PERL_ANYEVENT_STRICT"
1179 AnyEvent does not do much argument checking by default, as thorough 1258 AnyEvent does not do much argument checking by default, as thorough
1180 argument checking is very costly. Setting this variable to a true 1259 argument checking is very costly. Setting this variable to a true
1181 value will cause AnyEvent to load "AnyEvent::Strict" and then to 1260 value will cause AnyEvent to load "AnyEvent::Strict" and then to
1194 by "AnyEvent::Socket::parse_hostport" (after replacing every 1273 by "AnyEvent::Socket::parse_hostport" (after replacing every
1195 occurance of $$ by the process pid) and an "AnyEvent::Debug::shell" 1274 occurance of $$ by the process pid) and an "AnyEvent::Debug::shell"
1196 is bound on that port. The shell object is saved in 1275 is bound on that port. The shell object is saved in
1197 $AnyEvent::Debug::SHELL. 1276 $AnyEvent::Debug::SHELL.
1198 1277
1199 This takes place when the first watcher is created. 1278 This happens when the first watcher is created.
1200 1279
1201 For example, to bind a debug shell on a unix domain socket in 1280 For example, to bind a debug shell on a unix domain socket in
1202 /tmp/debug<pid>.sock, you could use this: 1281 /tmp/debug<pid>.sock, you could use this:
1203 1282
1204 PERL_ANYEVENT_DEBUG_SHELL=unix/:/tmp/debug\$\$.sock perlprog 1283 PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
1205 1284
1206 Note that creating sockets in /tmp is very unsafe on multiuser 1285 Note that creating sockets in /tmp is very unsafe on multiuser
1207 systems. 1286 systems.
1208 1287
1209 "PERL_ANYEVENT_DEBUG_WRAP" 1288 "PERL_ANYEVENT_DEBUG_WRAP"
1250 "PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to 1329 "PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to
1251 resolve or contact IPv6 addresses. 1330 resolve or contact IPv6 addresses.
1252 "PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4" support either IPv4 or IPv6, but 1331 "PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4" support either IPv4 or IPv6, but
1253 prefer IPv6 over IPv4. 1332 prefer IPv6 over IPv4.
1254 1333
1334 "PERL_ANYEVENT_HOSTS"
1335 This variable, if specified, overrides the /etc/hosts file used by
1336 AnyEvent::Socket"::resolve_sockaddr", i.e. hosts aliases will be
1337 read from that file instead.
1338
1255 "PERL_ANYEVENT_EDNS0" 1339 "PERL_ANYEVENT_EDNS0"
1256 Used by AnyEvent::DNS to decide whether to use the EDNS0 extension 1340 Used by AnyEvent::DNS to decide whether to use the EDNS0 extension
1257 for DNS. This extension is generally useful to reduce DNS traffic, 1341 for DNS. This extension is generally useful to reduce DNS traffic,
1258 but some (broken) firewalls drop such DNS packets, which is why it 1342 especially when DNSSEC is involved, but some (broken) firewalls drop
1259 is off by default. 1343 such DNS packets, which is why it is off by default.
1260 1344
1261 Setting this variable to 1 will cause AnyEvent::DNS to announce 1345 Setting this variable to 1 will cause AnyEvent::DNS to announce
1262 EDNS0 in its DNS requests. 1346 EDNS0 in its DNS requests.
1263 1347
1264 "PERL_ANYEVENT_MAX_FORKS" 1348 "PERL_ANYEVENT_MAX_FORKS"
1269 The default value for the "max_outstanding" parameter for the 1353 The default value for the "max_outstanding" parameter for the
1270 default DNS resolver - this is the maximum number of parallel DNS 1354 default DNS resolver - this is the maximum number of parallel DNS
1271 requests that are sent to the DNS server. 1355 requests that are sent to the DNS server.
1272 1356
1273 "PERL_ANYEVENT_RESOLV_CONF" 1357 "PERL_ANYEVENT_RESOLV_CONF"
1274 The file to use instead of /etc/resolv.conf (or OS-specific 1358 The absolute path to a resolv.conf-style file to use instead of
1275 configuration) in the default resolver. When set to the empty 1359 /etc/resolv.conf (or the OS-specific configuration) in the default
1276 string, no default config will be used. 1360 resolver, or the empty string to select the default configuration.
1277 1361
1278 "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH". 1362 "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH".
1279 When neither "ca_file" nor "ca_path" was specified during 1363 When neither "ca_file" nor "ca_path" was specified during
1280 AnyEvent::TLS context creation, and either of these environment 1364 AnyEvent::TLS context creation, and either of these environment
1281 variables exist, they will be used to specify CA certificate 1365 variables are nonempty, they will be used to specify CA certificate
1282 locations instead of a system-dependent default. 1366 locations instead of a system-dependent default.
1283 1367
1284 "PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT" 1368 "PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT"
1285 When these are set to 1, then the respective modules are not loaded. 1369 When these are set to 1, then the respective modules are not loaded.
1286 Mostly good for testing AnyEvent itself. 1370 Mostly good for testing AnyEvent itself.
1606 when used without AnyEvent), but most event loops have acceptable 1690 when used without AnyEvent), but most event loops have acceptable
1607 performance with or without AnyEvent. 1691 performance with or without AnyEvent.
1608 1692
1609 * The overhead AnyEvent adds is usually much smaller than the overhead 1693 * The overhead AnyEvent adds is usually much smaller than the overhead
1610 of the actual event loop, only with extremely fast event loops such 1694 of the actual event loop, only with extremely fast event loops such
1611 as EV adds AnyEvent significant overhead. 1695 as EV does AnyEvent add significant overhead.
1612 1696
1613 * You should avoid POE like the plague if you want performance or 1697 * You should avoid POE like the plague if you want performance or
1614 reasonable memory usage. 1698 reasonable memory usage.
1615 1699
1616 BENCHMARKING THE LARGE SERVER CASE 1700 BENCHMARKING THE LARGE SERVER CASE
1942SEE ALSO 2026SEE ALSO
1943 Tutorial/Introduction: AnyEvent::Intro. 2027 Tutorial/Introduction: AnyEvent::Intro.
1944 2028
1945 FAQ: AnyEvent::FAQ. 2029 FAQ: AnyEvent::FAQ.
1946 2030
1947 Utility functions: AnyEvent::Util. 2031 Utility functions: AnyEvent::Util (misc. grab-bag), AnyEvent::Log
2032 (simply logging).
1948 2033
2034 Development/Debugging: AnyEvent::Strict (stricter checking),
2035 AnyEvent::Debug (interactive shell, watcher tracing).
2036
1949 Event modules: AnyEvent::Loop, EV, EV::Glib, Glib::EV, Event, 2037 Supported event modules: AnyEvent::Loop, EV, EV::Glib, Glib::EV, Event,
1950 Glib::Event, Glib, Tk, Event::Lib, Qt, POE. 2038 Glib::Event, Glib, Tk, Event::Lib, Qt, POE, FLTK.
1951 2039
1952 Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event, 2040 Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event,
1953 AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl, 2041 AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl,
1954 AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE, 2042 AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE,
1955 AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi. 2043 AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi, AnyEvent::Impl::FLTK.
1956 2044
1957 Non-blocking file handles, sockets, TCP clients and servers: 2045 Non-blocking handles, pipes, stream sockets, TCP clients and servers:
1958 AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS. 2046 AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS.
1959 2047
1960 Asynchronous DNS: AnyEvent::DNS. 2048 Asynchronous DNS: AnyEvent::DNS.
1961 2049
1962 Thread support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event. 2050 Thread support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event.

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