1 | NAME |
1 | NAME |
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 | |
7 | SYNOPSIS |
7 | SYNOPSIS |
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 |
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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 | |
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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 | |
145 | WATCHERS |
145 | WATCHERS |
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. |
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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 | |
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403 | will not restart syscalls (that includes Async::Interrupt and AnyEvent's |
403 | will not restart syscalls (that includes Async::Interrupt and AnyEvent's |
404 | pure perl implementation). |
404 | pure perl implementation). |
405 | |
405 | |
406 | Safe/Unsafe Signals |
406 | Safe/Unsafe Signals |
407 | Perl signals can be either "safe" (synchronous to opcode handling) or |
407 | Perl signals can be either "safe" (synchronous to opcode handling) or |
408 | "unsafe" (asynchronous) - the former might get delayed indefinitely, the |
408 | "unsafe" (asynchronous) - the former might delay signal delivery |
409 | latter might corrupt your memory. |
409 | indefinitely, the latter might corrupt your memory. |
410 | |
410 | |
411 | AnyEvent signal handlers are, in addition, synchronous to the event |
411 | AnyEvent signal handlers are, in addition, synchronous to the event |
412 | loop, i.e. they will not interrupt your running perl program but will |
412 | loop, i.e. they will not interrupt your running perl program but will |
413 | only be called as part of the normal event handling (just like timer, |
413 | only be called as part of the normal event handling (just like timer, |
414 | I/O etc. callbacks, too). |
414 | I/O etc. callbacks, too). |
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416 | Signal Races, Delays and Workarounds |
416 | Signal Races, Delays and Workarounds |
417 | Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching |
417 | Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching |
418 | callbacks to signals in a generic way, which is a pity, as you cannot do |
418 | callbacks to signals in a generic way, which is a pity, as you cannot do |
419 | race-free signal handling in perl, requiring C libraries for this. |
419 | race-free signal handling in perl, requiring C libraries for this. |
420 | AnyEvent will try to do its best, which means in some cases, signals |
420 | AnyEvent will try to do its best, which means in some cases, signals |
421 | will be delayed. The maximum time a signal might be delayed is specified |
421 | will be delayed. The maximum time a signal might be delayed is 10 |
422 | in $AnyEvent::MAX_SIGNAL_LATENCY (default: 10 seconds). This variable |
422 | seconds by default, but can be overriden via |
423 | can be changed only before the first signal watcher is created, and |
423 | $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} or $AnyEvent::MAX_SIGNAL_LATENCY |
424 | should be left alone otherwise. This variable determines how often |
424 | - see the Ö<ENVIRONMENT VARIABLES> section for details. |
425 | AnyEvent polls for signals (in case a wake-up was missed). Higher values |
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426 | will cause fewer spurious wake-ups, which is better for power and CPU |
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427 | saving. |
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428 | |
425 | |
429 | All these problems can be avoided by installing the optional |
426 | All these problems can be avoided by installing the optional |
430 | Async::Interrupt module, which works with most event loops. It will not |
427 | Async::Interrupt module, which works with most event loops. It will not |
431 | work with inherently broken event loops such as Event or Event::Lib (and |
428 | work with inherently broken event loops such as Event or Event::Lib (and |
432 | not with POE currently, as POE does its own workaround with one-second |
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433 | latency). For those, you just have to suffer the delays. |
429 | not with POE currently). For those, you just have to suffer the delays. |
434 | |
430 | |
435 | CHILD PROCESS WATCHERS |
431 | CHILD PROCESS WATCHERS |
436 | $w = AnyEvent->child (pid => <process id>, cb => <callback>); |
432 | $w = AnyEvent->child (pid => <process id>, cb => <callback>); |
437 | |
433 | |
438 | You can also watch for a child process exit and catch its exit status. |
434 | You can also watch for a child process exit and catch its exit status. |
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466 | This means you cannot create a child watcher as the very first thing in |
462 | 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 |
463 | an AnyEvent program, you *have* to create at least one watcher before |
468 | you "fork" the child (alternatively, you can call "AnyEvent::detect"). |
464 | you "fork" the child (alternatively, you can call "AnyEvent::detect"). |
469 | |
465 | |
470 | As most event loops do not support waiting for child events, they will |
466 | 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 |
467 | be emulated by AnyEvent in most cases, in which case the latency and |
472 | problems mentioned in the description of signal watchers apply. |
468 | race problems mentioned in the description of signal watchers apply. |
473 | |
469 | |
474 | Example: fork a process and wait for it |
470 | Example: fork a process and wait for it |
475 | |
471 | |
476 | my $done = AnyEvent->condvar; |
472 | my $done = AnyEvent->condvar; |
477 | |
473 | |
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821 | use. If EV is not installed, then AnyEvent will fall back to its own |
817 | 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 |
818 | pure-perl implementation, which is available everywhere as it comes |
823 | with AnyEvent itself. |
819 | with AnyEvent itself. |
824 | |
820 | |
825 | AnyEvent::Impl::EV based on EV (interface to libev, best choice). |
821 | AnyEvent::Impl::EV based on EV (interface to libev, best choice). |
826 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
822 | AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable. |
827 | |
823 | |
828 | Backends that are transparently being picked up when they are used. |
824 | 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 |
825 | 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 |
826 | is created, in which case it is assumed that the application is |
831 | using them. This means that AnyEvent will automatically pick the |
827 | using them. This means that AnyEvent will automatically pick the |
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839 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
835 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
840 | AnyEvent::Impl::POE based on POE, very slow, some limitations. |
836 | AnyEvent::Impl::POE based on POE, very slow, some limitations. |
841 | AnyEvent::Impl::Irssi used when running within irssi. |
837 | AnyEvent::Impl::Irssi used when running within irssi. |
842 | AnyEvent::Impl::IOAsync based on IO::Async. |
838 | AnyEvent::Impl::IOAsync based on IO::Async. |
843 | AnyEvent::Impl::Cocoa based on Cocoa::EventLoop. |
839 | AnyEvent::Impl::Cocoa based on Cocoa::EventLoop. |
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840 | AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding). |
844 | |
841 | |
845 | Backends with special needs. |
842 | Backends with special needs. |
846 | Qt requires the Qt::Application to be instantiated first, but will |
843 | Qt requires the Qt::Application to be instantiated first, but will |
847 | otherwise be picked up automatically. As long as the main program |
844 | otherwise be picked up automatically. As long as the main program |
848 | instantiates the application before any AnyEvent watchers are |
845 | instantiates the application before any AnyEvent watchers are |
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885 | Returns $AnyEvent::MODEL, forcing autodetection of the event model |
882 | Returns $AnyEvent::MODEL, forcing autodetection of the event model |
886 | if necessary. You should only call this function right before you |
883 | if necessary. You should only call this function right before you |
887 | would have created an AnyEvent watcher anyway, that is, as late as |
884 | would have created an AnyEvent watcher anyway, that is, as late as |
888 | possible at runtime, and not e.g. during initialisation of your |
885 | possible at runtime, and not e.g. during initialisation of your |
889 | module. |
886 | module. |
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887 | |
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888 | The effect of calling this function is as if a watcher had been |
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889 | created (specifically, actions that happen "when the first watcher |
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890 | is created" happen when calling detetc as well). |
890 | |
891 | |
891 | If you need to do some initialisation before AnyEvent watchers are |
892 | If you need to do some initialisation before AnyEvent watchers are |
892 | created, use "post_detect". |
893 | created, use "post_detect". |
893 | |
894 | |
894 | $guard = AnyEvent::post_detect { BLOCK } |
895 | $guard = AnyEvent::post_detect { BLOCK } |
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956 | # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent |
957 | # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent |
957 | # as soon as it is |
958 | # as soon as it is |
958 | push @AnyEvent::post_detect, sub { require Coro::AnyEvent }; |
959 | push @AnyEvent::post_detect, sub { require Coro::AnyEvent }; |
959 | } |
960 | } |
960 | |
961 | |
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962 | AnyEvent::postpone { BLOCK } |
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963 | Arranges for the block to be executed as soon as possible, but not |
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964 | before the call itself returns. In practise, the block will be |
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965 | executed just before the event loop polls for new events, or shortly |
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966 | afterwards. |
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967 | |
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968 | This function never returns anything (to make the "return postpone { |
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969 | ... }" idiom more useful. |
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970 | |
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971 | To understand the usefulness of this function, consider a function |
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972 | that asynchronously does something for you and returns some |
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973 | transaction object or guard to let you cancel the operation. For |
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974 | example, "AnyEvent::Socket::tcp_connect": |
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975 | |
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976 | # start a conenction attempt unless one is active |
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977 | $self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub { |
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978 | delete $self->{connect_guard}; |
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979 | ... |
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980 | }; |
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981 | |
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982 | Imagine that this function could instantly call the callback, for |
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983 | example, because it detects an obvious error such as a negative port |
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984 | number. Invoking the callback before the function returns causes |
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985 | problems however: the callback will be called and will try to delete |
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986 | the guard object. But since the function hasn't returned yet, there |
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987 | is nothing to delete. When the function eventually returns it will |
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988 | assign the guard object to "$self->{connect_guard}", where it will |
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989 | likely never be deleted, so the program thinks it is still trying to |
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990 | connect. |
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991 | |
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992 | This is where "AnyEvent::postpone" should be used. Instead of |
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993 | calling the callback directly on error: |
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994 | |
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995 | $cb->(undef), return # signal error to callback, BAD! |
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996 | if $some_error_condition; |
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997 | |
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998 | It should use "postpone": |
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999 | |
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1000 | AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later |
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1001 | if $some_error_condition; |
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1002 | |
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1003 | AnyEvent::log $level, $msg[, @args] |
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1004 | Log the given $msg at the given $level. |
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1005 | |
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1006 | If AnyEvent::Log is not loaded then this function makes a simple |
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1007 | test to see whether the message will be logged. If the test succeeds |
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1008 | it will load AnyEvent::Log and call "AnyEvent::Log::log" - |
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1009 | consequently, look at the AnyEvent::Log documentation for details. |
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1010 | |
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1011 | If the test fails it will simply return. Right now this happens when |
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1012 | a numerical loglevel is used and it is larger than the level |
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1013 | specified via $ENV{PERL_ANYEVENT_VERBOSE}. |
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1014 | |
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1015 | If you want to sprinkle loads of logging calls around your code, |
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1016 | consider creating a logger callback with the "AnyEvent::Log::logger" |
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1017 | function, which can reduce typing, codesize and can reduce the |
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1018 | logging overhead enourmously. |
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1019 | |
961 | WHAT TO DO IN A MODULE |
1020 | WHAT TO DO IN A MODULE |
962 | As a module author, you should "use AnyEvent" and call AnyEvent methods |
1021 | 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. |
1022 | freely, but you should not load a specific event module or rely on it. |
964 | |
1023 | |
965 | Be careful when you create watchers in the module body - AnyEvent will |
1024 | Be careful when you create watchers in the module body - AnyEvent will |
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995 | will decide on the event model to use as soon as it creates watchers, |
1054 | 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 |
1055 | and it might choose the wrong one unless you load the correct one |
997 | yourself. |
1056 | yourself. |
998 | |
1057 | |
999 | You can chose to use a pure-perl implementation by loading the |
1058 | You can chose to use a pure-perl implementation by loading the |
1000 | "AnyEvent::Impl::Perl" module, which gives you similar behaviour |
1059 | "AnyEvent::Loop" module, which gives you similar behaviour everywhere, |
1001 | everywhere, but letting AnyEvent chose the model is generally better. |
1060 | but letting AnyEvent chose the model is generally better. |
1002 | |
1061 | |
1003 | MAINLOOP EMULATION |
1062 | MAINLOOP EMULATION |
1004 | Sometimes (often for short test scripts, or even standalone programs who |
1063 | 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 |
1064 | only want to use AnyEvent), you do not want to run a specific event |
1006 | loop. |
1065 | loop. |
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1018 | |
1077 | |
1019 | OTHER MODULES |
1078 | OTHER MODULES |
1020 | The following is a non-exhaustive list of additional modules that use |
1079 | 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 |
1080 | 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 |
1081 | 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. |
1082 | modules come as part of AnyEvent, the others are available via CPAN (see |
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1083 | <http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for a longer |
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1084 | non-exhaustive list), and the list is heavily biased towards modules of |
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1085 | the AnyEvent author himself :) |
1024 | |
1086 | |
1025 | AnyEvent::Util |
1087 | AnyEvent::Util |
1026 | Contains various utility functions that replace often-used blocking |
1088 | Contains various utility functions that replace often-used blocking |
1027 | functions such as "inet_aton" with event/callback-based versions. |
1089 | functions such as "inet_aton" with event/callback-based versions. |
1028 | |
1090 | |
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1044 | AnyEvent::IGS, AnyEvent::FCP |
1106 | AnyEvent::IGS, AnyEvent::FCP |
1045 | Implement event-based interfaces to the protocols of the same name |
1107 | 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 |
1108 | (for the curious, IGS is the International Go Server and FCP is the |
1047 | Freenet Client Protocol). |
1109 | Freenet Client Protocol). |
1048 | |
1110 | |
1049 | AnyEvent::Handle::UDP |
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1050 | Here be danger! |
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1051 | |
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1052 | As Pauli would put it, "Not only is it not right, it's not even |
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1053 | wrong!" - there are so many things wrong with AnyEvent::Handle::UDP, |
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1054 | most notably its use of a stream-based API with a protocol that |
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1055 | isn't streamable, that the only way to improve it is to delete it. |
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1056 | |
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1057 | It features data corruption (but typically only under load) and |
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1058 | general confusion. On top, the author is not only clueless about UDP |
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1059 | but also fact-resistant - some gems of his understanding: "connect |
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1060 | doesn't work with UDP", "UDP packets are not IP packets", "UDP only |
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1061 | has datagrams, not packets", "I don't need to implement proper error |
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1062 | checking as UDP doesn't support error checking" and so on - he |
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1063 | doesn't even understand what's wrong with his module when it is |
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1064 | explained to him. |
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1065 | |
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1066 | AnyEvent::DBI |
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1067 | Executes DBI requests asynchronously in a proxy process for you, |
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1068 | notifying you in an event-based way when the operation is finished. |
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1069 | |
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1070 | AnyEvent::AIO |
1111 | AnyEvent::AIO |
1071 | Truly asynchronous (as opposed to non-blocking) I/O, should be in |
1112 | Truly asynchronous (as opposed to non-blocking) I/O, should be in |
1072 | the toolbox of every event programmer. AnyEvent::AIO transparently |
1113 | the toolbox of every event programmer. AnyEvent::AIO transparently |
1073 | fuses IO::AIO and AnyEvent together, giving AnyEvent access to |
1114 | fuses IO::AIO and AnyEvent together, giving AnyEvent access to |
1074 | event-based file I/O, and much more. |
1115 | event-based file I/O, and much more. |
1075 | |
1116 | |
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1117 | AnyEvent::Filesys::Notify |
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1118 | AnyEvent is good for non-blocking stuff, but it can't detect file or |
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1119 | path changes (e.g. "watch this directory for new files", "watch this |
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1120 | file for changes"). The AnyEvent::Filesys::Notify module promises to |
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1121 | do just that in a portbale fashion, supporting inotify on GNU/Linux |
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1122 | and some weird, without doubt broken, stuff on OS X to monitor |
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1123 | files. It can fall back to blocking scans at regular intervals |
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1124 | transparently on other platforms, so it's about as portable as it |
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1125 | gets. |
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1126 | |
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1127 | (I haven't used it myself, but I haven't heard anybody complaining |
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1128 | about it yet). |
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1129 | |
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1130 | AnyEvent::DBI |
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1131 | Executes DBI requests asynchronously in a proxy process for you, |
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1132 | notifying you in an event-based way when the operation is finished. |
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1133 | |
1076 | AnyEvent::HTTPD |
1134 | AnyEvent::HTTPD |
1077 | A simple embedded webserver. |
1135 | A simple embedded webserver. |
1078 | |
1136 | |
1079 | AnyEvent::FastPing |
1137 | AnyEvent::FastPing |
1080 | The fastest ping in the west. |
1138 | The fastest ping in the west. |
1081 | |
1139 | |
1082 | Coro |
1140 | Coro |
1083 | Has special support for AnyEvent via Coro::AnyEvent. |
1141 | Has special support for AnyEvent via Coro::AnyEvent, which allows |
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1142 | you to simply invert the flow control - don't call us, we will call |
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1143 | you: |
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1144 | |
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1145 | async { |
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1146 | Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it |
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1147 | print "5 seconds later!\n"; |
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1148 | |
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1149 | Coro::AnyEvent::readable *STDIN; # uses an I/O watcher |
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1150 | my $line = <STDIN>; # works for ttys |
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1151 | |
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1152 | AnyEvent::HTTP::http_get "url", Coro::rouse_cb; |
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1153 | my ($body, $hdr) = Coro::rouse_wait; |
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1154 | }; |
1084 | |
1155 | |
1085 | SIMPLIFIED AE API |
1156 | SIMPLIFIED AE API |
1086 | Starting with version 5.0, AnyEvent officially supports a second, much |
1157 | Starting with version 5.0, AnyEvent officially supports a second, much |
1087 | simpler, API that is designed to reduce the calling, typing and memory |
1158 | simpler, API that is designed to reduce the calling, typing and memory |
1088 | overhead by using function call syntax and a fixed number of parameters. |
1159 | overhead by using function call syntax and a fixed number of parameters. |
… | |
… | |
1104 | The pure perl event loop simply re-throws the exception (usually within |
1175 | The pure perl event loop simply re-throws the exception (usually within |
1105 | "condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()", |
1176 | "condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()", |
1106 | Glib uses "install_exception_handler" and so on. |
1177 | Glib uses "install_exception_handler" and so on. |
1107 | |
1178 | |
1108 | ENVIRONMENT VARIABLES |
1179 | ENVIRONMENT VARIABLES |
1109 | The following environment variables are used by this module or its |
1180 | AnyEvent supports a number of environment variables that tune the |
1110 | submodules. |
1181 | runtime behaviour. They are usually evaluated when AnyEvent is loaded, |
|
|
1182 | initialised, or a submodule that uses them is loaded. Many of them also |
|
|
1183 | cause AnyEvent to load additional modules - for example, |
|
|
1184 | "PERL_ANYEVENT_DEBUG_WRAP" causes the AnyEvent::Debug module to be |
|
|
1185 | loaded. |
1111 | |
1186 | |
1112 | Note that AnyEvent will remove *all* environment variables starting with |
1187 | All the environment variables documented here start with |
1113 | "PERL_ANYEVENT_" from %ENV when it is loaded while taint mode is |
1188 | "PERL_ANYEVENT_", which is what AnyEvent considers its own namespace. |
1114 | enabled. |
1189 | Other modules are encouraged (but by no means required) to use |
|
|
1190 | "PERL_ANYEVENT_SUBMODULE" if they have registered the |
|
|
1191 | AnyEvent::Submodule namespace on CPAN, for any submodule. For example, |
|
|
1192 | AnyEvent::HTTP could be expected to use "PERL_ANYEVENT_HTTP_PROXY" (it |
|
|
1193 | should not access env variables starting with "AE_", see below). |
|
|
1194 | |
|
|
1195 | All variables can also be set via the "AE_" prefix, that is, instead of |
|
|
1196 | setting "PERL_ANYEVENT_VERBOSE" you can also set "AE_VERBOSE". In case |
|
|
1197 | there is a clash btween anyevent and another program that uses |
|
|
1198 | "AE_something" you can set the corresponding "PERL_ANYEVENT_something" |
|
|
1199 | variable to the empty string, as those variables take precedence. |
|
|
1200 | |
|
|
1201 | When AnyEvent is first loaded, it copies all "AE_xxx" env variables to |
|
|
1202 | their "PERL_ANYEVENT_xxx" counterpart unless that variable already |
|
|
1203 | exists. If taint mode is on, then AnyEvent will remove *all* environment |
|
|
1204 | variables starting with "PERL_ANYEVENT_" from %ENV (or replace them with |
|
|
1205 | "undef" or the empty string, if the corresaponding "AE_" variable is |
|
|
1206 | set). |
|
|
1207 | |
|
|
1208 | The exact algorithm is currently: |
|
|
1209 | |
|
|
1210 | 1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV |
|
|
1211 | 2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists |
|
|
1212 | 3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef. |
|
|
1213 | |
|
|
1214 | This ensures that child processes will not see the "AE_" variables. |
|
|
1215 | |
|
|
1216 | The following environment variables are currently known to AnyEvent: |
1115 | |
1217 | |
1116 | "PERL_ANYEVENT_VERBOSE" |
1218 | "PERL_ANYEVENT_VERBOSE" |
1117 | By default, AnyEvent will be completely silent except in fatal |
1219 | By default, AnyEvent will only log messages with loglevel 3 |
1118 | conditions. You can set this environment variable to make AnyEvent |
1220 | ("critical") or higher (see AnyEvent::Log). You can set this |
|
|
1221 | environment variable to a numerical loglevel to make AnyEvent more |
1119 | more talkative. |
1222 | (or less) talkative. |
1120 | |
1223 | |
|
|
1224 | If you want to do more than just set the global logging level you |
|
|
1225 | should have a look at "PERL_ANYEVENT_LOG", which allows much more |
|
|
1226 | complex specifications. |
|
|
1227 | |
|
|
1228 | When set to 0 ("off"), then no messages whatsoever will be logged |
|
|
1229 | with the default logging settings. |
|
|
1230 | |
1121 | When set to 1 or higher, causes AnyEvent to warn about unexpected |
1231 | 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 |
1232 | unexpected conditions, such as not being able to load the event |
1123 | by "PERL_ANYEVENT_MODEL". |
1233 | model specified by "PERL_ANYEVENT_MODEL", or a guard callback |
|
|
1234 | throwing an exception - this is the minimum recommended level. |
1124 | |
1235 | |
1125 | When set to 2 or higher, cause AnyEvent to report to STDERR which |
1236 | When set to 7 or higher (info), cause AnyEvent to report which event |
1126 | event model it chooses. |
1237 | model it chooses. |
1127 | |
1238 | |
1128 | When set to 8 or higher, then AnyEvent will report extra information |
1239 | When set to 8 or higher (debug), then AnyEvent will report extra |
1129 | on which optional modules it loads and how it implements certain |
1240 | information on which optional modules it loads and how it implements |
1130 | features. |
1241 | certain features. |
|
|
1242 | |
|
|
1243 | "PERL_ANYEVENT_LOG" |
|
|
1244 | Accepts rather complex logging specifications. For example, you |
|
|
1245 | could log all "debug" messages of some module to stderr, warnings |
|
|
1246 | and above to stderr, and errors and above to syslog, with: |
|
|
1247 | |
|
|
1248 | PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog |
|
|
1249 | |
|
|
1250 | For the rather extensive details, see AnyEvent::Log. |
|
|
1251 | |
|
|
1252 | This variable is evaluated when AnyEvent (or AnyEvent::Log) is |
|
|
1253 | loaded, so will take effect even before AnyEvent has initialised |
|
|
1254 | itself. |
|
|
1255 | |
|
|
1256 | Note that specifying this environment variable causes the |
|
|
1257 | AnyEvent::Log module to be loaded, while "PERL_ANYEVENT_VERBOSE" |
|
|
1258 | does not, so only using the latter saves a few hundred kB of memory |
|
|
1259 | until the first message is being logged. |
1131 | |
1260 | |
1132 | "PERL_ANYEVENT_STRICT" |
1261 | "PERL_ANYEVENT_STRICT" |
1133 | AnyEvent does not do much argument checking by default, as thorough |
1262 | AnyEvent does not do much argument checking by default, as thorough |
1134 | argument checking is very costly. Setting this variable to a true |
1263 | argument checking is very costly. Setting this variable to a true |
1135 | value will cause AnyEvent to load "AnyEvent::Strict" and then to |
1264 | value will cause AnyEvent to load "AnyEvent::Strict" and then to |
… | |
… | |
1141 | Unlike "use strict" (or its modern cousin, "use common::sense", it |
1270 | Unlike "use strict" (or its modern cousin, "use common::sense", it |
1142 | is definitely recommended to keep it off in production. Keeping |
1271 | is definitely recommended to keep it off in production. Keeping |
1143 | "PERL_ANYEVENT_STRICT=1" in your environment while developing |
1272 | "PERL_ANYEVENT_STRICT=1" in your environment while developing |
1144 | programs can be very useful, however. |
1273 | programs can be very useful, however. |
1145 | |
1274 | |
|
|
1275 | "PERL_ANYEVENT_DEBUG_SHELL" |
|
|
1276 | If this env variable is nonempty, then its contents will be |
|
|
1277 | interpreted by "AnyEvent::Socket::parse_hostport" and |
|
|
1278 | "AnyEvent::Debug::shell" (after replacing every occurance of $$ by |
|
|
1279 | the process pid). The shell object is saved in |
|
|
1280 | $AnyEvent::Debug::SHELL. |
|
|
1281 | |
|
|
1282 | This happens when the first watcher is created. |
|
|
1283 | |
|
|
1284 | For example, to bind a debug shell on a unix domain socket in |
|
|
1285 | /tmp/debug<pid>.sock, you could use this: |
|
|
1286 | |
|
|
1287 | PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog |
|
|
1288 | # connect with e.g.: socat readline /tmp/debug123.sock |
|
|
1289 | |
|
|
1290 | Or to bind to tcp port 4545 on localhost: |
|
|
1291 | |
|
|
1292 | PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog |
|
|
1293 | # connect with e.g.: telnet localhost 4545 |
|
|
1294 | |
|
|
1295 | Note that creating sockets in /tmp or on localhost is very unsafe on |
|
|
1296 | multiuser systems. |
|
|
1297 | |
|
|
1298 | "PERL_ANYEVENT_DEBUG_WRAP" |
|
|
1299 | Can be set to 0, 1 or 2 and enables wrapping of all watchers for |
|
|
1300 | debugging purposes. See "AnyEvent::Debug::wrap" for details. |
|
|
1301 | |
1146 | "PERL_ANYEVENT_MODEL" |
1302 | "PERL_ANYEVENT_MODEL" |
1147 | This can be used to specify the event model to be used by AnyEvent, |
1303 | 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 |
1304 | before auto detection and -probing kicks in. |
1149 | consisting entirely of ASCII letters. The string "AnyEvent::Impl::" |
1305 | |
1150 | gets prepended and the resulting module name is loaded and if the |
1306 | 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 |
1307 | "EV" or "IOAsync"). The string "AnyEvent::Impl::" gets prepended and |
|
|
1308 | the resulting module name is loaded and - if the load was successful |
|
|
1309 | - used as event model backend. If it fails to load then AnyEvent |
1152 | AnyEvent will proceed with auto detection and -probing. |
1310 | will proceed with auto detection and -probing. |
1153 | |
1311 | |
1154 | This functionality might change in future versions. |
1312 | If the string ends with "::" instead (e.g. "AnyEvent::Impl::EV::") |
|
|
1313 | then nothing gets prepended and the module name is used as-is (hint: |
|
|
1314 | "::" at the end of a string designates a module name and quotes it |
|
|
1315 | appropriately). |
1155 | |
1316 | |
1156 | For example, to force the pure perl model (AnyEvent::Impl::Perl) you |
1317 | For example, to force the pure perl model (AnyEvent::Loop::Perl) you |
1157 | could start your program like this: |
1318 | could start your program like this: |
1158 | |
1319 | |
1159 | PERL_ANYEVENT_MODEL=Perl perl ... |
1320 | PERL_ANYEVENT_MODEL=Perl perl ... |
1160 | |
1321 | |
1161 | "PERL_ANYEVENT_PROTOCOLS" |
1322 | "PERL_ANYEVENT_PROTOCOLS" |
… | |
… | |
1178 | "PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to |
1339 | "PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to |
1179 | resolve or contact IPv6 addresses. |
1340 | resolve or contact IPv6 addresses. |
1180 | "PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4" support either IPv4 or IPv6, but |
1341 | "PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4" support either IPv4 or IPv6, but |
1181 | prefer IPv6 over IPv4. |
1342 | prefer IPv6 over IPv4. |
1182 | |
1343 | |
|
|
1344 | "PERL_ANYEVENT_HOSTS" |
|
|
1345 | This variable, if specified, overrides the /etc/hosts file used by |
|
|
1346 | AnyEvent::Socket"::resolve_sockaddr", i.e. hosts aliases will be |
|
|
1347 | read from that file instead. |
|
|
1348 | |
1183 | "PERL_ANYEVENT_EDNS0" |
1349 | "PERL_ANYEVENT_EDNS0" |
1184 | Used by AnyEvent::DNS to decide whether to use the EDNS0 extension |
1350 | Used by AnyEvent::DNS to decide whether to use the EDNS0 extension |
1185 | for DNS. This extension is generally useful to reduce DNS traffic, |
1351 | for DNS. This extension is generally useful to reduce DNS traffic, |
1186 | but some (broken) firewalls drop such DNS packets, which is why it |
1352 | especially when DNSSEC is involved, but some (broken) firewalls drop |
1187 | is off by default. |
1353 | such DNS packets, which is why it is off by default. |
1188 | |
1354 | |
1189 | Setting this variable to 1 will cause AnyEvent::DNS to announce |
1355 | Setting this variable to 1 will cause AnyEvent::DNS to announce |
1190 | EDNS0 in its DNS requests. |
1356 | EDNS0 in its DNS requests. |
1191 | |
1357 | |
1192 | "PERL_ANYEVENT_MAX_FORKS" |
1358 | "PERL_ANYEVENT_MAX_FORKS" |
… | |
… | |
1196 | "PERL_ANYEVENT_MAX_OUTSTANDING_DNS" |
1362 | "PERL_ANYEVENT_MAX_OUTSTANDING_DNS" |
1197 | The default value for the "max_outstanding" parameter for the |
1363 | The default value for the "max_outstanding" parameter for the |
1198 | default DNS resolver - this is the maximum number of parallel DNS |
1364 | default DNS resolver - this is the maximum number of parallel DNS |
1199 | requests that are sent to the DNS server. |
1365 | requests that are sent to the DNS server. |
1200 | |
1366 | |
|
|
1367 | "PERL_ANYEVENT_MAX_SIGNAL_LATENCY" |
|
|
1368 | Perl has inherently racy signal handling (you can basically choose |
|
|
1369 | between losing signals and memory corruption) - pure perl event |
|
|
1370 | loops (including "AnyEvent::Loop", when "Async::Interrupt" isn't |
|
|
1371 | available) therefore have to poll regularly to avoid losing signals. |
|
|
1372 | |
|
|
1373 | Some event loops are racy, but don't poll regularly, and some event |
|
|
1374 | loops are written in C but are still racy. For those event loops, |
|
|
1375 | AnyEvent installs a timer that regularly wakes up the event loop. |
|
|
1376 | |
|
|
1377 | By default, the interval for this timer is 10 seconds, but you can |
|
|
1378 | override this delay with this environment variable (or by setting |
|
|
1379 | the $AnyEvent::MAX_SIGNAL_LATENCY variable before creating signal |
|
|
1380 | watchers). |
|
|
1381 | |
|
|
1382 | Lower values increase CPU (and energy) usage, higher values can |
|
|
1383 | introduce long delays when reaping children or waiting for signals. |
|
|
1384 | |
|
|
1385 | The AnyEvent::Async module, if available, will be used to avoid this |
|
|
1386 | polling (with most event loops). |
|
|
1387 | |
1201 | "PERL_ANYEVENT_RESOLV_CONF" |
1388 | "PERL_ANYEVENT_RESOLV_CONF" |
1202 | The file to use instead of /etc/resolv.conf (or OS-specific |
1389 | The absolute path to a resolv.conf-style file to use instead of |
1203 | configuration) in the default resolver. When set to the empty |
1390 | /etc/resolv.conf (or the OS-specific configuration) in the default |
1204 | string, no default config will be used. |
1391 | resolver, or the empty string to select the default configuration. |
1205 | |
1392 | |
1206 | "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH". |
1393 | "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH". |
1207 | When neither "ca_file" nor "ca_path" was specified during |
1394 | When neither "ca_file" nor "ca_path" was specified during |
1208 | AnyEvent::TLS context creation, and either of these environment |
1395 | AnyEvent::TLS context creation, and either of these environment |
1209 | variables exist, they will be used to specify CA certificate |
1396 | variables are nonempty, they will be used to specify CA certificate |
1210 | locations instead of a system-dependent default. |
1397 | locations instead of a system-dependent default. |
1211 | |
1398 | |
1212 | "PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT" |
1399 | "PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT" |
1213 | When these are set to 1, then the respective modules are not loaded. |
1400 | When these are set to 1, then the respective modules are not loaded. |
1214 | Mostly good for testing AnyEvent itself. |
1401 | Mostly good for testing AnyEvent itself. |
… | |
… | |
1534 | when used without AnyEvent), but most event loops have acceptable |
1721 | when used without AnyEvent), but most event loops have acceptable |
1535 | performance with or without AnyEvent. |
1722 | performance with or without AnyEvent. |
1536 | |
1723 | |
1537 | * The overhead AnyEvent adds is usually much smaller than the overhead |
1724 | * The overhead AnyEvent adds is usually much smaller than the overhead |
1538 | of the actual event loop, only with extremely fast event loops such |
1725 | of the actual event loop, only with extremely fast event loops such |
1539 | as EV adds AnyEvent significant overhead. |
1726 | as EV does AnyEvent add significant overhead. |
1540 | |
1727 | |
1541 | * You should avoid POE like the plague if you want performance or |
1728 | * You should avoid POE like the plague if you want performance or |
1542 | reasonable memory usage. |
1729 | reasonable memory usage. |
1543 | |
1730 | |
1544 | BENCHMARKING THE LARGE SERVER CASE |
1731 | BENCHMARKING THE LARGE SERVER CASE |
… | |
… | |
1804 | the help of AnyEvent::TLS), gains the ability to do TLS/SSL. |
1991 | the help of AnyEvent::TLS), gains the ability to do TLS/SSL. |
1805 | |
1992 | |
1806 | Time::HiRes |
1993 | Time::HiRes |
1807 | This module is part of perl since release 5.008. It will be used |
1994 | 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 |
1995 | 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 |
1996 | its own. The pure-perl event loop (AnyEvent::Loop) will additionally |
1810 | additionally use it to try to use a monotonic clock for timing |
1997 | load it to try to use a monotonic clock for timing stability. |
1811 | stability. |
|
|
1812 | |
1998 | |
1813 | FORK |
1999 | FORK |
1814 | Most event libraries are not fork-safe. The ones who are usually are |
2000 | 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 |
2001 | 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 |
2002 | - higher performance APIs such as BSD's kqueue or the dreaded Linux |
… | |
… | |
1871 | SEE ALSO |
2057 | SEE ALSO |
1872 | Tutorial/Introduction: AnyEvent::Intro. |
2058 | Tutorial/Introduction: AnyEvent::Intro. |
1873 | |
2059 | |
1874 | FAQ: AnyEvent::FAQ. |
2060 | FAQ: AnyEvent::FAQ. |
1875 | |
2061 | |
1876 | Utility functions: AnyEvent::Util. |
2062 | Utility functions: AnyEvent::Util (misc. grab-bag), AnyEvent::Log |
|
|
2063 | (simply logging). |
1877 | |
2064 | |
1878 | Event modules: EV, EV::Glib, Glib::EV, Event, Glib::Event, Glib, Tk, |
2065 | Development/Debugging: AnyEvent::Strict (stricter checking), |
1879 | Event::Lib, Qt, POE. |
2066 | AnyEvent::Debug (interactive shell, watcher tracing). |
|
|
2067 | |
|
|
2068 | Supported event modules: AnyEvent::Loop, EV, EV::Glib, Glib::EV, Event, |
|
|
2069 | Glib::Event, Glib, Tk, Event::Lib, Qt, POE, FLTK. |
1880 | |
2070 | |
1881 | Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event, |
2071 | Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event, |
1882 | AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl, |
2072 | AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl, |
1883 | AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE, |
2073 | AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE, |
1884 | AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi. |
2074 | AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi, AnyEvent::Impl::FLTK. |
1885 | |
2075 | |
1886 | Non-blocking file handles, sockets, TCP clients and servers: |
2076 | Non-blocking handles, pipes, stream sockets, TCP clients and servers: |
1887 | AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS. |
2077 | AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS. |
1888 | |
2078 | |
1889 | Asynchronous DNS: AnyEvent::DNS. |
2079 | Asynchronous DNS: AnyEvent::DNS. |
1890 | |
2080 | |
1891 | Thread support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event. |
2081 | Thread support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event. |