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Revision 1.64 by root, Fri Dec 31 04:50:44 2010 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
… …
115 The interface itself is vaguely similar, but not identical to the Event 115 The interface itself is vaguely similar, but not identical to the Event
116 module. 116 module.
117 117
118 During the first call of any watcher-creation method, the module tries 118 During the first call of any watcher-creation method, the module tries
119 to detect the currently loaded event loop by probing whether one of the 119 to detect the currently loaded event loop by probing whether one of the
120 following modules is already loaded: EV, AnyEvent::Impl::Perl, Event, 120 following modules is already loaded: EV, AnyEvent::Loop, Event, Glib,
121 Glib, Tk, Event::Lib, Qt, POE. The first one found is used. If none are 121 Tk, Event::Lib, Qt, POE. The first one found is used. If none are
122 detected, the module tries to load the first four modules in the order 122 detected, the module tries to load the first four modules in the order
123 given; but note that if EV is not available, the pure-perl 123 given; but note that if EV is not available, the pure-perl
124 AnyEvent::Impl::Perl should always work, so the other two are not 124 AnyEvent::Loop should always work, so the other two are not normally
125 normally tried. 125 tried.
126 126
127 Because AnyEvent first checks for modules that are already loaded, 127 Because AnyEvent first checks for modules that are already loaded,
128 loading an event model explicitly before first using AnyEvent will 128 loading an event model explicitly before first using AnyEvent will
129 likely make that model the default. For example: 129 likely make that model the default. For example:
130 130
… …
136 The *likely* means that, if any module loads another event model and 136 The *likely* means that, if any module loads another event model and
137 starts using it, all bets are off - this case should be very rare 137 starts using it, all bets are off - this case should be very rare
138 though, as very few modules hardcode event loops without announcing this 138 though, as very few modules hardcode event loops without announcing this
139 very loudly. 139 very loudly.
140 140
141 The pure-perl implementation of AnyEvent is called 141 The pure-perl implementation of AnyEvent is called "AnyEvent::Loop".
142 "AnyEvent::Impl::Perl". Like other event modules you can load it 142 Like other event modules you can load it explicitly and enjoy the high
143 explicitly and enjoy the high availability of that event loop :) 143 availability of that event loop :)
144 144
145WATCHERS 145WATCHERS
146 AnyEvent has the central concept of a *watcher*, which is an object that 146 AnyEvent has the central concept of a *watcher*, which is an object that
147 stores relevant data for each kind of event you are waiting for, such as 147 stores relevant data for each kind of event you are waiting for, such as
148 the callback to call, the file handle to watch, etc. 148 the callback to call, the file handle to watch, etc.
… …
347 can get whatever behaviour you want with any event loop, by taking 347 can get whatever behaviour you want with any event loop, by taking
348 the difference between "AnyEvent->time" and "AnyEvent->now" into 348 the difference between "AnyEvent->time" and "AnyEvent->now" into
349 account. 349 account.
350 350
351 AnyEvent->now_update 351 AnyEvent->now_update
352 Some event loops (such as EV or AnyEvent::Impl::Perl) cache the 352 Some event loops (such as EV or AnyEvent::Loop) cache the current
353 current time for each loop iteration (see the discussion of 353 time for each loop iteration (see the discussion of AnyEvent->now,
354 AnyEvent->now, above). 354 above).
355 355
356 When a callback runs for a long time (or when the process sleeps), 356 When a callback runs for a long time (or when the process sleeps),
357 then this "current" time will differ substantially from the real 357 then this "current" time will differ substantially from the real
358 time, which might affect timers and time-outs. 358 time, which might affect timers and time-outs.
359 359
… …
466 This means you cannot create a child watcher as the very first thing in 466 This means you cannot create a child watcher as the very first thing in
467 an AnyEvent program, you *have* to create at least one watcher before 467 an AnyEvent program, you *have* to create at least one watcher before
468 you "fork" the child (alternatively, you can call "AnyEvent::detect"). 468 you "fork" the child (alternatively, you can call "AnyEvent::detect").
469 469
470 As most event loops do not support waiting for child events, they will 470 As most event loops do not support waiting for child events, they will
471 be emulated by AnyEvent in most cases, in which the latency and race 471 be emulated by AnyEvent in most cases, in which case the latency and
472 problems mentioned in the description of signal watchers apply. 472 race problems mentioned in the description of signal watchers apply.
473 473
474 Example: fork a process and wait for it 474 Example: fork a process and wait for it
475 475
476 my $done = AnyEvent->condvar; 476 my $done = AnyEvent->condvar;
477 477
… …
821 use. If EV is not installed, then AnyEvent will fall back to its own 821 use. If EV is not installed, then AnyEvent will fall back to its own
822 pure-perl implementation, which is available everywhere as it comes 822 pure-perl implementation, which is available everywhere as it comes
823 with AnyEvent itself. 823 with AnyEvent itself.
824 824
825 AnyEvent::Impl::EV based on EV (interface to libev, best choice). 825 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
826 AnyEvent::Impl::Perl pure-perl implementation, fast and portable. 826 AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
827 827
828 Backends that are transparently being picked up when they are used. 828 Backends that are transparently being picked up when they are used.
829 These will be used if they are already loaded when the first watcher 829 These will be used if they are already loaded when the first watcher
830 is created, in which case it is assumed that the application is 830 is created, in which case it is assumed that the application is
831 using them. This means that AnyEvent will automatically pick the 831 using them. This means that AnyEvent will automatically pick the
… …
839 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. 839 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
840 AnyEvent::Impl::POE based on POE, very slow, some limitations. 840 AnyEvent::Impl::POE based on POE, very slow, some limitations.
841 AnyEvent::Impl::Irssi used when running within irssi. 841 AnyEvent::Impl::Irssi used when running within irssi.
842 AnyEvent::Impl::IOAsync based on IO::Async. 842 AnyEvent::Impl::IOAsync based on IO::Async.
843 AnyEvent::Impl::Cocoa based on Cocoa::EventLoop. 843 AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
844 AnyEvent::Impl::FLTK2 based on FLTK (fltk 2 binding).
844 845
845 Backends with special needs. 846 Backends with special needs.
846 Qt requires the Qt::Application to be instantiated first, but will 847 Qt requires the Qt::Application to be instantiated first, but will
847 otherwise be picked up automatically. As long as the main program 848 otherwise be picked up automatically. As long as the main program
848 instantiates the application before any AnyEvent watchers are 849 instantiates the application before any AnyEvent watchers are
… …
885 Returns $AnyEvent::MODEL, forcing autodetection of the event model 886 Returns $AnyEvent::MODEL, forcing autodetection of the event model
886 if necessary. You should only call this function right before you 887 if necessary. You should only call this function right before you
887 would have created an AnyEvent watcher anyway, that is, as late as 888 would have created an AnyEvent watcher anyway, that is, as late as
888 possible at runtime, and not e.g. during initialisation of your 889 possible at runtime, and not e.g. during initialisation of your
889 module. 890 module.
891
892 The effect of calling this function is as if a watcher had been
893 created (specifically, actions that happen "when the first watcher
894 is created" happen when calling detetc as well).
890 895
891 If you need to do some initialisation before AnyEvent watchers are 896 If you need to do some initialisation before AnyEvent watchers are
892 created, use "post_detect". 897 created, use "post_detect".
893 898
894 $guard = AnyEvent::post_detect { BLOCK } 899 $guard = AnyEvent::post_detect { BLOCK }
… …
956 # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent 961 # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
957 # as soon as it is 962 # as soon as it is
958 push @AnyEvent::post_detect, sub { require Coro::AnyEvent }; 963 push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
959 } 964 }
960 965
966 AnyEvent::postpone { BLOCK }
967 Arranges for the block to be executed as soon as possible, but not
968 before the call itself returns. In practise, the block will be
969 executed just before the event loop polls for new events, or shortly
970 afterwards.
971
972 This function never returns anything (to make the "return postpone {
973 ... }" idiom more useful.
974
975 To understand the usefulness of this function, consider a function
976 that asynchronously does something for you and returns some
977 transaction object or guard to let you cancel the operation. For
978 example, "AnyEvent::Socket::tcp_connect":
979
980 # start a conenction attempt unless one is active
981 $self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
982 delete $self->{connect_guard};
983 ...
984 };
985
986 Imagine that this function could instantly call the callback, for
987 example, because it detects an obvious error such as a negative port
988 number. Invoking the callback before the function returns causes
989 problems however: the callback will be called and will try to delete
990 the guard object. But since the function hasn't returned yet, there
991 is nothing to delete. When the function eventually returns it will
992 assign the guard object to "$self->{connect_guard}", where it will
993 likely never be deleted, so the program thinks it is still trying to
994 connect.
995
996 This is where "AnyEvent::postpone" should be used. Instead of
997 calling the callback directly on error:
998
999 $cb->(undef), return # signal error to callback, BAD!
1000 if $some_error_condition;
1001
1002 It should use "postpone":
1003
1004 AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
1005 if $some_error_condition;
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
961WHAT TO DO IN A MODULE 1022WHAT TO DO IN A MODULE
962 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
963 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.
964 1025
965 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
… …
995 will decide on the event model to use as soon as it creates watchers, 1056 will decide on the event model to use as soon as it creates watchers,
996 and it might choose the wrong one unless you load the correct one 1057 and it might choose the wrong one unless you load the correct one
997 yourself. 1058 yourself.
998 1059
999 You can chose to use a pure-perl implementation by loading the 1060 You can chose to use a pure-perl implementation by loading the
1000 "AnyEvent::Impl::Perl" module, which gives you similar behaviour 1061 "AnyEvent::Loop" module, which gives you similar behaviour everywhere,
1001 everywhere, but letting AnyEvent chose the model is generally better. 1062 but letting AnyEvent chose the model is generally better.
1002 1063
1003 MAINLOOP EMULATION 1064 MAINLOOP EMULATION
1004 Sometimes (often for short test scripts, or even standalone programs who 1065 Sometimes (often for short test scripts, or even standalone programs who
1005 only want to use AnyEvent), you do not want to run a specific event 1066 only want to use AnyEvent), you do not want to run a specific event
1006 loop. 1067 loop.
… …
1018 1079
1019OTHER MODULES 1080OTHER MODULES
1020 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
1021 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
1022 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
1023 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 :)
1024 1088
1025 AnyEvent::Util 1089 AnyEvent::Util
1026 Contains various utility functions that replace often-used blocking 1090 Contains various utility functions that replace often-used blocking
1027 functions such as "inet_aton" with event/callback-based versions. 1091 functions such as "inet_aton" with event/callback-based versions.
1028 1092
… …
1044 AnyEvent::IGS, AnyEvent::FCP 1108 AnyEvent::IGS, AnyEvent::FCP
1045 Implement event-based interfaces to the protocols of the same name 1109 Implement event-based interfaces to the protocols of the same name
1046 (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
1047 Freenet Client Protocol). 1111 Freenet Client Protocol).
1048 1112
1049 AnyEvent::Handle::UDP
1050 Here be danger!
1051
1052 As Pauli would put it, "Not only is it not right, it's not even
1053 wrong!" - there are so many things wrong with AnyEvent::Handle::UDP,
1054 most notably its use of a stream-based API with a protocol that
1055 isn't streamable, that the only way to improve it is to delete it.
1056
1057 It features data corruption (but typically only under load) and
1058 general confusion. On top, the author is not only clueless about UDP
1059 but also fact-resistant - some gems of his understanding: "connect
1060 doesn't work with UDP", "UDP packets are not IP packets", "UDP only
1061 has datagrams, not packets", "I don't need to implement proper error
1062 checking as UDP doesn't support error checking" and so on - he
1063 doesn't even understand what's wrong with his module when it is
1064 explained to him.
1065
1066 AnyEvent::DBI
1067 Executes DBI requests asynchronously in a proxy process for you,
1068 notifying you in an event-based way when the operation is finished.
1069
1070 AnyEvent::AIO 1113 AnyEvent::AIO
1071 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
1072 the toolbox of every event programmer. AnyEvent::AIO transparently 1115 the toolbox of every event programmer. AnyEvent::AIO transparently
1073 fuses IO::AIO and AnyEvent together, giving AnyEvent access to 1116 fuses IO::AIO and AnyEvent together, giving AnyEvent access to
1074 event-based file I/O, and much more. 1117 event-based file I/O, and much more.
1075 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
1076 AnyEvent::HTTPD 1136 AnyEvent::HTTPD
1077 A simple embedded webserver. 1137 A simple embedded webserver.
1078 1138
1079 AnyEvent::FastPing 1139 AnyEvent::FastPing
1080 The fastest ping in the west. 1140 The fastest ping in the west.
1081 1141
1082 Coro 1142 Coro
1083 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, $hdr) = Coro::rouse_wait;
1156 };
1084 1157
1085SIMPLIFIED AE API 1158SIMPLIFIED AE API
1086 Starting with version 5.0, AnyEvent officially supports a second, much 1159 Starting with version 5.0, AnyEvent officially supports a second, much
1087 simpler, API that is designed to reduce the calling, typing and memory 1160 simpler, API that is designed to reduce the calling, typing and memory
1088 overhead by using function call syntax and a fixed number of parameters. 1161 overhead by using function call syntax and a fixed number of parameters.
… …
1104 The pure perl event loop simply re-throws the exception (usually within 1177 The pure perl event loop simply re-throws the exception (usually within
1105 "condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()", 1178 "condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()",
1106 Glib uses "install_exception_handler" and so on. 1179 Glib uses "install_exception_handler" and so on.
1107 1180
1108ENVIRONMENT VARIABLES 1181ENVIRONMENT VARIABLES
1109 The following environment variables are used by this module or its 1182 AnyEvent supports a number of environment variables that tune the
1110 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.
1111 1188
1112 Note that AnyEvent will remove *all* environment variables starting with 1189 All the environment variables documented here start with
1113 "PERL_ANYEVENT_" from %ENV when it is loaded while taint mode is 1190 "PERL_ANYEVENT_", which is what AnyEvent considers its own namespace.
1114 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:
1115 1219
1116 "PERL_ANYEVENT_VERBOSE" 1220 "PERL_ANYEVENT_VERBOSE"
1117 By default, AnyEvent will be completely silent except in fatal 1221 By default, AnyEvent will be completely silent except in fatal
1118 conditions. You can set this environment variable to make AnyEvent 1222 conditions. You can set this environment variable to make AnyEvent
1119 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.
1120 1226
1121 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
1122 conditions, such as not being able to load the event model specified 1228 unexpected conditions, such as not being able to load the event
1123 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.
1124 1231
1125 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
1126 event model it chooses. 1233 model it chooses.
1127 1234
1128 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
1129 on which optional modules it loads and how it implements certain 1236 information on which optional modules it loads and how it implements
1130 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.
1131 1256
1132 "PERL_ANYEVENT_STRICT" 1257 "PERL_ANYEVENT_STRICT"
1133 AnyEvent does not do much argument checking by default, as thorough 1258 AnyEvent does not do much argument checking by default, as thorough
1134 argument checking is very costly. Setting this variable to a true 1259 argument checking is very costly. Setting this variable to a true
1135 value will cause AnyEvent to load "AnyEvent::Strict" and then to 1260 value will cause AnyEvent to load "AnyEvent::Strict" and then to
… …
1141 Unlike "use strict" (or its modern cousin, "use common::sense", it 1266 Unlike "use strict" (or its modern cousin, "use common::sense", it
1142 is definitely recommended to keep it off in production. Keeping 1267 is definitely recommended to keep it off in production. Keeping
1143 "PERL_ANYEVENT_STRICT=1" in your environment while developing 1268 "PERL_ANYEVENT_STRICT=1" in your environment while developing
1144 programs can be very useful, however. 1269 programs can be very useful, however.
1145 1270
1271 "PERL_ANYEVENT_DEBUG_SHELL"
1272 If this env variable is set, then its contents will be interpreted
1273 by "AnyEvent::Socket::parse_hostport" (after replacing every
1274 occurance of $$ by the process pid) and an "AnyEvent::Debug::shell"
1275 is bound on that port. The shell object is saved in
1276 $AnyEvent::Debug::SHELL.
1277
1278 This happens when the first watcher is created.
1279
1280 For example, to bind a debug shell on a unix domain socket in
1281 /tmp/debug<pid>.sock, you could use this:
1282
1283 PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
1284
1285 Note that creating sockets in /tmp is very unsafe on multiuser
1286 systems.
1287
1288 "PERL_ANYEVENT_DEBUG_WRAP"
1289 Can be set to 0, 1 or 2 and enables wrapping of all watchers for
1290 debugging purposes. See "AnyEvent::Debug::wrap" for details.
1291
1146 "PERL_ANYEVENT_MODEL" 1292 "PERL_ANYEVENT_MODEL"
1147 This can be used to specify the event model to be used by AnyEvent, 1293 This can be used to specify the event model to be used by AnyEvent,
1148 before auto detection and -probing kicks in. It must be a string 1294 before auto detection and -probing kicks in.
1149 consisting entirely of ASCII letters. The string "AnyEvent::Impl::" 1295
1150 gets prepended and the resulting module name is loaded and if the 1296 It normally is a string consisting entirely of ASCII letters (e.g.
1151 load was successful, used as event model. If it fails to load 1297 "EV" or "IOAsync"). The string "AnyEvent::Impl::" gets prepended and
1298 the resulting module name is loaded and - if the load was successful
1299 - used as event model backend. If it fails to load then AnyEvent
1152 AnyEvent will proceed with auto detection and -probing. 1300 will proceed with auto detection and -probing.
1153 1301
1154 This functionality might change in future versions. 1302 If the string ends with "::" instead (e.g. "AnyEvent::Impl::EV::")
1303 then nothing gets prepended and the module name is used as-is (hint:
1304 "::" at the end of a string designates a module name and quotes it
1305 appropriately).
1155 1306
1156 For example, to force the pure perl model (AnyEvent::Impl::Perl) you 1307 For example, to force the pure perl model (AnyEvent::Loop::Perl) you
1157 could start your program like this: 1308 could start your program like this:
1158 1309
1159 PERL_ANYEVENT_MODEL=Perl perl ... 1310 PERL_ANYEVENT_MODEL=Perl perl ...
1160 1311
1161 "PERL_ANYEVENT_PROTOCOLS" 1312 "PERL_ANYEVENT_PROTOCOLS"
… …
1178 "PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to 1329 "PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to
1179 resolve or contact IPv6 addresses. 1330 resolve or contact IPv6 addresses.
1180 "PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4" support either IPv4 or IPv6, but 1331 "PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4" support either IPv4 or IPv6, but
1181 prefer IPv6 over IPv4. 1332 prefer IPv6 over IPv4.
1182 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
1183 "PERL_ANYEVENT_EDNS0" 1339 "PERL_ANYEVENT_EDNS0"
1184 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
1185 for DNS. This extension is generally useful to reduce DNS traffic, 1341 for DNS. This extension is generally useful to reduce DNS traffic,
1186 but some (broken) firewalls drop such DNS packets, which is why it 1342 especially when DNSSEC is involved, but some (broken) firewalls drop
1187 is off by default. 1343 such DNS packets, which is why it is off by default.
1188 1344
1189 Setting this variable to 1 will cause AnyEvent::DNS to announce 1345 Setting this variable to 1 will cause AnyEvent::DNS to announce
1190 EDNS0 in its DNS requests. 1346 EDNS0 in its DNS requests.
1191 1347
1192 "PERL_ANYEVENT_MAX_FORKS" 1348 "PERL_ANYEVENT_MAX_FORKS"
… …
1197 The default value for the "max_outstanding" parameter for the 1353 The default value for the "max_outstanding" parameter for the
1198 default DNS resolver - this is the maximum number of parallel DNS 1354 default DNS resolver - this is the maximum number of parallel DNS
1199 requests that are sent to the DNS server. 1355 requests that are sent to the DNS server.
1200 1356
1201 "PERL_ANYEVENT_RESOLV_CONF" 1357 "PERL_ANYEVENT_RESOLV_CONF"
1202 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
1203 configuration) in the default resolver. When set to the empty 1359 /etc/resolv.conf (or the OS-specific configuration) in the default
1204 string, no default config will be used. 1360 resolver, or the empty string to select the default configuration.
1205 1361
1206 "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH". 1362 "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH".
1207 When neither "ca_file" nor "ca_path" was specified during 1363 When neither "ca_file" nor "ca_path" was specified during
1208 AnyEvent::TLS context creation, and either of these environment 1364 AnyEvent::TLS context creation, and either of these environment
1209 variables exist, they will be used to specify CA certificate 1365 variables are nonempty, they will be used to specify CA certificate
1210 locations instead of a system-dependent default. 1366 locations instead of a system-dependent default.
1211 1367
1212 "PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT" 1368 "PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT"
1213 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.
1214 Mostly good for testing AnyEvent itself. 1370 Mostly good for testing AnyEvent itself.
… …
1534 when used without AnyEvent), but most event loops have acceptable 1690 when used without AnyEvent), but most event loops have acceptable
1535 performance with or without AnyEvent. 1691 performance with or without AnyEvent.
1536 1692
1537 * The overhead AnyEvent adds is usually much smaller than the overhead 1693 * The overhead AnyEvent adds is usually much smaller than the overhead
1538 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
1539 as EV adds AnyEvent significant overhead. 1695 as EV does AnyEvent add significant overhead.
1540 1696
1541 * 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
1542 reasonable memory usage. 1698 reasonable memory usage.
1543 1699
1544 BENCHMARKING THE LARGE SERVER CASE 1700 BENCHMARKING THE LARGE SERVER CASE
… …
1804 the help of AnyEvent::TLS), gains the ability to do TLS/SSL. 1960 the help of AnyEvent::TLS), gains the ability to do TLS/SSL.
1805 1961
1806 Time::HiRes 1962 Time::HiRes
1807 This module is part of perl since release 5.008. It will be used 1963 This module is part of perl since release 5.008. It will be used
1808 when the chosen event library does not come with a timing source of 1964 when the chosen event library does not come with a timing source of
1809 its own. The pure-perl event loop (AnyEvent::Impl::Perl) will 1965 its own. The pure-perl event loop (AnyEvent::Loop) will additionally
1810 additionally use it to try to use a monotonic clock for timing 1966 load it to try to use a monotonic clock for timing stability.
1811 stability.
1812 1967
1813FORK 1968FORK
1814 Most event libraries are not fork-safe. The ones who are usually are 1969 Most event libraries are not fork-safe. The ones who are usually are
1815 because they rely on inefficient but fork-safe "select" or "poll" calls 1970 because they rely on inefficient but fork-safe "select" or "poll" calls
1816 - higher performance APIs such as BSD's kqueue or the dreaded Linux 1971 - higher performance APIs such as BSD's kqueue or the dreaded Linux
… …
1871SEE ALSO 2026SEE ALSO
1872 Tutorial/Introduction: AnyEvent::Intro. 2027 Tutorial/Introduction: AnyEvent::Intro.
1873 2028
1874 FAQ: AnyEvent::FAQ. 2029 FAQ: AnyEvent::FAQ.
1875 2030
1876 Utility functions: AnyEvent::Util. 2031 Utility functions: AnyEvent::Util (misc. grab-bag), AnyEvent::Log
2032 (simply logging).
1877 2033
1878 Event modules: EV, EV::Glib, Glib::EV, Event, Glib::Event, Glib, Tk, 2034 Development/Debugging: AnyEvent::Strict (stricter checking),
1879 Event::Lib, Qt, POE. 2035 AnyEvent::Debug (interactive shell, watcher tracing).
2036
2037 Supported event modules: AnyEvent::Loop, EV, EV::Glib, Glib::EV, Event,
2038 Glib::Event, Glib, Tk, Event::Lib, Qt, POE, FLTK.
1880 2039
1881 Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event, 2040 Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event,
1882 AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl, 2041 AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl,
1883 AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE, 2042 AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE,
1884 AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi. 2043 AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi, AnyEvent::Impl::FLTK.
1885 2044
1886 Non-blocking file handles, sockets, TCP clients and servers: 2045 Non-blocking handles, pipes, stream sockets, TCP clients and servers:
1887 AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS. 2046 AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS.
1888 2047
1889 Asynchronous DNS: AnyEvent::DNS. 2048 Asynchronous DNS: AnyEvent::DNS.
1890 2049
1891 Thread support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event. 2050 Thread support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event.

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