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Revision 1.63 by root, Wed Oct 13 19:49:46 2010 UTC vs.
Revision 1.68 by root, Fri Aug 26 18:09:04 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
… …
80 that isn't them. What's worse, all the potential users of your module 80 that isn't them. What's worse, all the potential users of your module
81 are *also* forced to use the same event loop you use. 81 are *also* forced to use the same event loop you use.
82 82
83 AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works 83 AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
84 fine. AnyEvent + Tk works fine etc. etc. but none of these work together 84 fine. AnyEvent + Tk works fine etc. etc. but none of these work together
85 with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if your 85 with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module
86 module uses one of those, every user of your module has to use it, too. 86 uses one of those, every user of your module has to use it, too. But if
87 But if your module uses AnyEvent, it works transparently with all event 87 your module uses AnyEvent, it works transparently with all event models
88 models it supports (including stuff like IO::Async, as long as those use 88 it supports (including stuff like IO::Async, as long as those use one of
89 one of the supported event loops. It is easy to add new event loops to 89 the supported event loops. It is easy to add new event loops to
90 AnyEvent, too, so it is future-proof). 90 AnyEvent, too, so it is future-proof).
91 91
92 In addition to being free of having to use *the one and only true event 92 In addition to being free of having to use *the one and only true event
93 model*, AnyEvent also is free of bloat and policy: with POE or similar 93 model*, AnyEvent also is free of bloat and policy: with POE or similar
94 modules, you get an enormous amount of code and strict rules you have to 94 modules, you get an enormous amount of code and strict rules you have to
… …
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
… …
837 AnyEvent::Impl::Glib based on Glib, slow but very stable. 837 AnyEvent::Impl::Glib based on Glib, slow but very stable.
838 AnyEvent::Impl::Tk based on Tk, very broken. 838 AnyEvent::Impl::Tk based on Tk, very broken.
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.
843 AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
844 AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding).
842 845
843 Backends with special needs. 846 Backends with special needs.
844 Qt requires the Qt::Application to be instantiated first, but will 847 Qt requires the Qt::Application to be instantiated first, but will
845 otherwise be picked up automatically. As long as the main program 848 otherwise be picked up automatically. As long as the main program
846 instantiates the application before any AnyEvent watchers are 849 instantiates the application before any AnyEvent watchers are
847 created, everything should just work. 850 created, everything should just work.
848 851
849 AnyEvent::Impl::Qt based on Qt. 852 AnyEvent::Impl::Qt based on Qt.
850
851 Support for IO::Async can only be partial, as it is too broken and
852 architecturally limited to even support the AnyEvent API. It also is
853 the only event loop that needs the loop to be set explicitly, so it
854 can only be used by a main program knowing about AnyEvent. See
855 AnyEvent::Impl::IOAsync for the gory details.
856
857 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
858 853
859 Event loops that are indirectly supported via other backends. 854 Event loops that are indirectly supported via other backends.
860 Some event loops can be supported via other modules: 855 Some event loops can be supported via other modules:
861 856
862 There is no direct support for WxWidgets (Wx) or Prima. 857 There is no direct support for WxWidgets (Wx) or Prima.
… …
891 Returns $AnyEvent::MODEL, forcing autodetection of the event model 886 Returns $AnyEvent::MODEL, forcing autodetection of the event model
892 if necessary. You should only call this function right before you 887 if necessary. You should only call this function right before you
893 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
894 possible at runtime, and not e.g. during initialisation of your 889 possible at runtime, and not e.g. during initialisation of your
895 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).
896 895
897 If you need to do some initialisation before AnyEvent watchers are 896 If you need to do some initialisation before AnyEvent watchers are
898 created, use "post_detect". 897 created, use "post_detect".
899 898
900 $guard = AnyEvent::post_detect { BLOCK } 899 $guard = AnyEvent::post_detect { BLOCK }
… …
962 # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent 961 # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
963 # as soon as it is 962 # as soon as it is
964 push @AnyEvent::post_detect, sub { require Coro::AnyEvent }; 963 push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
965 } 964 }
966 965
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
967WHAT TO DO IN A MODULE 1022WHAT TO DO IN A MODULE
968 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
969 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.
970 1025
971 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
… …
1001 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,
1002 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
1003 yourself. 1058 yourself.
1004 1059
1005 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
1006 "AnyEvent::Impl::Perl" module, which gives you similar behaviour 1061 "AnyEvent::Loop" module, which gives you similar behaviour everywhere,
1007 everywhere, but letting AnyEvent chose the model is generally better. 1062 but letting AnyEvent chose the model is generally better.
1008 1063
1009 MAINLOOP EMULATION 1064 MAINLOOP EMULATION
1010 Sometimes (often for short test scripts, or even standalone programs who 1065 Sometimes (often for short test scripts, or even standalone programs who
1011 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
1012 loop. 1067 loop.
… …
1024 1079
1025OTHER MODULES 1080OTHER MODULES
1026 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
1027 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
1028 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
1029 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 :)
1030 1088
1031 AnyEvent::Util 1089 AnyEvent::Util
1032 Contains various utility functions that replace often-used blocking 1090 Contains various utility functions that replace often-used blocking
1033 functions such as "inet_aton" with event/callback-based versions. 1091 functions such as "inet_aton" with event/callback-based versions.
1034 1092
… …
1050 AnyEvent::IGS, AnyEvent::FCP 1108 AnyEvent::IGS, AnyEvent::FCP
1051 Implement event-based interfaces to the protocols of the same name 1109 Implement event-based interfaces to the protocols of the same name
1052 (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
1053 Freenet Client Protocol). 1111 Freenet Client Protocol).
1054 1112
1055 AnyEvent::Handle::UDP
1056 Here be danger!
1057
1058 As Pauli would put it, "Not only is it not right, it's not even
1059 wrong!" - there are so many things wrong with AnyEvent::Handle::UDP,
1060 most notably its use of a stream-based API with a protocol that
1061 isn't streamable, that the only way to improve it is to delete it.
1062
1063 It features data corruption (but typically only under load) and
1064 general confusion. On top, the author is not only clueless about UDP
1065 but also fact-resistant - some gems of his understanding: "connect
1066 doesn't work with UDP", "UDP packets are not IP packets", "UDP only
1067 has datagrams, not packets", "I don't need to implement proper error
1068 checking as UDP doesn't support error checking" and so on - he
1069 doesn't even understand what's wrong with his module when it is
1070 explained to him.
1071
1072 AnyEvent::DBI
1073 Executes DBI requests asynchronously in a proxy process for you,
1074 notifying you in an event-based way when the operation is finished.
1075
1076 AnyEvent::AIO 1113 AnyEvent::AIO
1077 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
1078 the toolbox of every event programmer. AnyEvent::AIO transparently 1115 the toolbox of every event programmer. AnyEvent::AIO transparently
1079 fuses IO::AIO and AnyEvent together, giving AnyEvent access to 1116 fuses IO::AIO and AnyEvent together, giving AnyEvent access to
1080 event-based file I/O, and much more. 1117 event-based file I/O, and much more.
1081 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
1082 AnyEvent::HTTPD 1136 AnyEvent::HTTPD
1083 A simple embedded webserver. 1137 A simple embedded webserver.
1084 1138
1085 AnyEvent::FastPing 1139 AnyEvent::FastPing
1086 The fastest ping in the west. 1140 The fastest ping in the west.
1087 1141
1088 Coro 1142 Coro
1089 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, $hdr) = Coro::rouse_wait;
1156 };
1090 1157
1091SIMPLIFIED AE API 1158SIMPLIFIED AE API
1092 Starting with version 5.0, AnyEvent officially supports a second, much 1159 Starting with version 5.0, AnyEvent officially supports a second, much
1093 simpler, API that is designed to reduce the calling, typing and memory 1160 simpler, API that is designed to reduce the calling, typing and memory
1094 overhead by using function call syntax and a fixed number of parameters. 1161 overhead by using function call syntax and a fixed number of parameters.
… …
1110 The pure perl event loop simply re-throws the exception (usually within 1177 The pure perl event loop simply re-throws the exception (usually within
1111 "condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()", 1178 "condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()",
1112 Glib uses "install_exception_handler" and so on. 1179 Glib uses "install_exception_handler" and so on.
1113 1180
1114ENVIRONMENT VARIABLES 1181ENVIRONMENT VARIABLES
1115 The following environment variables are used by this module or its 1182 AnyEvent supports a number of environment variables that tune the
1116 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.
1117 1188
1118 Note that AnyEvent will remove *all* environment variables starting with 1189 All the environment variables documented here start with
1119 "PERL_ANYEVENT_" from %ENV when it is loaded while taint mode is 1190 "PERL_ANYEVENT_", which is what AnyEvent considers its own namespace.
1120 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:
1121 1219
1122 "PERL_ANYEVENT_VERBOSE" 1220 "PERL_ANYEVENT_VERBOSE"
1123 By default, AnyEvent will be completely silent except in fatal 1221 By default, AnyEvent will be completely silent except in fatal
1124 conditions. You can set this environment variable to make AnyEvent 1222 conditions. You can set this environment variable to make AnyEvent
1125 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.
1126 1226
1127 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
1128 conditions, such as not being able to load the event model specified 1228 unexpected conditions, such as not being able to load the event
1129 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.
1130 1231
1131 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
1132 event model it chooses. 1233 model it chooses.
1133 1234
1134 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
1135 on which optional modules it loads and how it implements certain 1236 information on which optional modules it loads and how it implements
1136 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.
1137 1256
1138 "PERL_ANYEVENT_STRICT" 1257 "PERL_ANYEVENT_STRICT"
1139 AnyEvent does not do much argument checking by default, as thorough 1258 AnyEvent does not do much argument checking by default, as thorough
1140 argument checking is very costly. Setting this variable to a true 1259 argument checking is very costly. Setting this variable to a true
1141 value will cause AnyEvent to load "AnyEvent::Strict" and then to 1260 value will cause AnyEvent to load "AnyEvent::Strict" and then to
… …
1147 Unlike "use strict" (or its modern cousin, "use common::sense", it 1266 Unlike "use strict" (or its modern cousin, "use common::sense", it
1148 is definitely recommended to keep it off in production. Keeping 1267 is definitely recommended to keep it off in production. Keeping
1149 "PERL_ANYEVENT_STRICT=1" in your environment while developing 1268 "PERL_ANYEVENT_STRICT=1" in your environment while developing
1150 programs can be very useful, however. 1269 programs can be very useful, however.
1151 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
1152 "PERL_ANYEVENT_MODEL" 1292 "PERL_ANYEVENT_MODEL"
1153 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,
1154 before auto detection and -probing kicks in. It must be a string 1294 before auto detection and -probing kicks in.
1155 consisting entirely of ASCII letters. The string "AnyEvent::Impl::" 1295
1156 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.
1157 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
1158 AnyEvent will proceed with auto detection and -probing. 1300 will proceed with auto detection and -probing.
1159 1301
1160 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).
1161 1306
1162 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
1163 could start your program like this: 1308 could start your program like this:
1164 1309
1165 PERL_ANYEVENT_MODEL=Perl perl ... 1310 PERL_ANYEVENT_MODEL=Perl perl ...
1166 1311
1167 "PERL_ANYEVENT_PROTOCOLS" 1312 "PERL_ANYEVENT_PROTOCOLS"
… …
1184 "PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to 1329 "PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to
1185 resolve or contact IPv6 addresses. 1330 resolve or contact IPv6 addresses.
1186 "PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4" support either IPv4 or IPv6, but 1331 "PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4" support either IPv4 or IPv6, but
1187 prefer IPv6 over IPv4. 1332 prefer IPv6 over IPv4.
1188 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
1189 "PERL_ANYEVENT_EDNS0" 1339 "PERL_ANYEVENT_EDNS0"
1190 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
1191 for DNS. This extension is generally useful to reduce DNS traffic, 1341 for DNS. This extension is generally useful to reduce DNS traffic,
1192 but some (broken) firewalls drop such DNS packets, which is why it 1342 especially when DNSSEC is involved, but some (broken) firewalls drop
1193 is off by default. 1343 such DNS packets, which is why it is off by default.
1194 1344
1195 Setting this variable to 1 will cause AnyEvent::DNS to announce 1345 Setting this variable to 1 will cause AnyEvent::DNS to announce
1196 EDNS0 in its DNS requests. 1346 EDNS0 in its DNS requests.
1197 1347
1198 "PERL_ANYEVENT_MAX_FORKS" 1348 "PERL_ANYEVENT_MAX_FORKS"
… …
1203 The default value for the "max_outstanding" parameter for the 1353 The default value for the "max_outstanding" parameter for the
1204 default DNS resolver - this is the maximum number of parallel DNS 1354 default DNS resolver - this is the maximum number of parallel DNS
1205 requests that are sent to the DNS server. 1355 requests that are sent to the DNS server.
1206 1356
1207 "PERL_ANYEVENT_RESOLV_CONF" 1357 "PERL_ANYEVENT_RESOLV_CONF"
1208 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
1209 configuration) in the default resolver. When set to the empty 1359 /etc/resolv.conf (or the OS-specific configuration) in the default
1210 string, no default config will be used. 1360 resolver, or the empty string to select the default configuration.
1211 1361
1212 "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH". 1362 "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH".
1213 When neither "ca_file" nor "ca_path" was specified during 1363 When neither "ca_file" nor "ca_path" was specified during
1214 AnyEvent::TLS context creation, and either of these environment 1364 AnyEvent::TLS context creation, and either of these environment
1215 variables exist, they will be used to specify CA certificate 1365 variables are nonempty, they will be used to specify CA certificate
1216 locations instead of a system-dependent default. 1366 locations instead of a system-dependent default.
1217 1367
1218 "PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT" 1368 "PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT"
1219 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.
1220 Mostly good for testing AnyEvent itself. 1370 Mostly good for testing AnyEvent itself.
… …
1540 when used without AnyEvent), but most event loops have acceptable 1690 when used without AnyEvent), but most event loops have acceptable
1541 performance with or without AnyEvent. 1691 performance with or without AnyEvent.
1542 1692
1543 * The overhead AnyEvent adds is usually much smaller than the overhead 1693 * The overhead AnyEvent adds is usually much smaller than the overhead
1544 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
1545 as EV adds AnyEvent significant overhead. 1695 as EV does AnyEvent add significant overhead.
1546 1696
1547 * 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
1548 reasonable memory usage. 1698 reasonable memory usage.
1549 1699
1550 BENCHMARKING THE LARGE SERVER CASE 1700 BENCHMARKING THE LARGE SERVER CASE
… …
1810 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.
1811 1961
1812 Time::HiRes 1962 Time::HiRes
1813 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
1814 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
1815 its own. The pure-perl event loop (AnyEvent::Impl::Perl) will 1965 its own. The pure-perl event loop (AnyEvent::Loop) will additionally
1816 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.
1817 stability.
1818 1967
1819FORK 1968FORK
1820 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
1821 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
1822 - 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
… …
1877SEE ALSO 2026SEE ALSO
1878 Tutorial/Introduction: AnyEvent::Intro. 2027 Tutorial/Introduction: AnyEvent::Intro.
1879 2028
1880 FAQ: AnyEvent::FAQ. 2029 FAQ: AnyEvent::FAQ.
1881 2030
1882 Utility functions: AnyEvent::Util. 2031 Utility functions: AnyEvent::Util (misc. grab-bag), AnyEvent::Log
2032 (simply logging).
1883 2033
1884 Event modules: EV, EV::Glib, Glib::EV, Event, Glib::Event, Glib, Tk, 2034 Development/Debugging: AnyEvent::Strict (stricter checking),
1885 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.
1886 2039
1887 Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event, 2040 Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event,
1888 AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl, 2041 AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl,
1889 AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE, 2042 AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE,
1890 AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi. 2043 AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi, AnyEvent::Impl::FLTK.
1891 2044
1892 Non-blocking file handles, sockets, TCP clients and servers: 2045 Non-blocking handles, pipes, stream sockets, TCP clients and servers:
1893 AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS. 2046 AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS.
1894 2047
1895 Asynchronous DNS: AnyEvent::DNS. 2048 Asynchronous DNS: AnyEvent::DNS.
1896 2049
1897 Thread support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event. 2050 Thread support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event.

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