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1=head1 NAME 1=head1 => NAME
2 2
3AnyEvent - provide framework for multiple event loops 3AnyEvent - provide framework for multiple event loops
4 4
5EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops 5EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops
6 6
17 }); 17 });
18 18
19 my $w = AnyEvent->condvar; # stores whether a condition was flagged 19 my $w = AnyEvent->condvar; # stores whether a condition was flagged
20 $w->send; # wake up current and all future recv's 20 $w->send; # wake up current and all future recv's
21 $w->recv; # enters "main loop" till $condvar gets ->send 21 $w->recv; # enters "main loop" till $condvar gets ->send
22
23=head1 INTRODUCTION/TUTORIAL
24
25This manpage is mainly a reference manual. If you are interested
26in a tutorial or some gentle introduction, have a look at the
27L<AnyEvent::Intro> manpage.
22 28
23=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) 29=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24 30
25Glib, POE, IO::Async, Event... CPAN offers event models by the dozen 31Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26nowadays. So what is different about AnyEvent? 32nowadays. So what is different about AnyEvent?
48isn't itself. What's worse, all the potential users of your module are 54isn't itself. What's worse, all the potential users of your module are
49I<also> forced to use the same event loop you use. 55I<also> forced to use the same event loop you use.
50 56
51AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works 57AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52fine. AnyEvent + Tk works fine etc. etc. but none of these work together 58fine. AnyEvent + Tk works fine etc. etc. but none of these work together
53with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if 59with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
54your module uses one of those, every user of your module has to use it, 60your module uses one of those, every user of your module has to use it,
55too. But if your module uses AnyEvent, it works transparently with all 61too. But if your module uses AnyEvent, it works transparently with all
56event models it supports (including stuff like POE and IO::Async, as long 62event models it supports (including stuff like POE and IO::Async, as long
57as those use one of the supported event loops. It is trivial to add new 63as those use one of the supported event loops. It is trivial to add new
58event loops to AnyEvent, too, so it is future-proof). 64event loops to AnyEvent, too, so it is future-proof).
59 65
60In addition to being free of having to use I<the one and only true event 66In addition to being free of having to use I<the one and only true event
61model>, AnyEvent also is free of bloat and policy: with POE or similar 67model>, AnyEvent also is free of bloat and policy: with POE or similar
62modules, you get an enourmous amount of code and strict rules you have to 68modules, you get an enormous amount of code and strict rules you have to
63follow. AnyEvent, on the other hand, is lean and up to the point, by only 69follow. AnyEvent, on the other hand, is lean and up to the point, by only
64offering the functionality that is necessary, in as thin as a wrapper as 70offering the functionality that is necessary, in as thin as a wrapper as
65technically possible. 71technically possible.
66 72
73Of course, AnyEvent comes with a big (and fully optional!) toolbox
74of useful functionality, such as an asynchronous DNS resolver, 100%
75non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
76such as Windows) and lots of real-world knowledge and workarounds for
77platform bugs and differences.
78
67Of course, if you want lots of policy (this can arguably be somewhat 79Now, if you I<do want> lots of policy (this can arguably be somewhat
68useful) and you want to force your users to use the one and only event 80useful) and you want to force your users to use the one and only event
69model, you should I<not> use this module. 81model, you should I<not> use this module.
70 82
71=head1 DESCRIPTION 83=head1 DESCRIPTION
72 84
102starts using it, all bets are off. Maybe you should tell their authors to 114starts using it, all bets are off. Maybe you should tell their authors to
103use AnyEvent so their modules work together with others seamlessly... 115use AnyEvent so their modules work together with others seamlessly...
104 116
105The pure-perl implementation of AnyEvent is called 117The pure-perl implementation of AnyEvent is called
106C<AnyEvent::Impl::Perl>. Like other event modules you can load it 118C<AnyEvent::Impl::Perl>. Like other event modules you can load it
107explicitly. 119explicitly and enjoy the high availability of that event loop :)
108 120
109=head1 WATCHERS 121=head1 WATCHERS
110 122
111AnyEvent has the central concept of a I<watcher>, which is an object that 123AnyEvent has the central concept of a I<watcher>, which is an object that
112stores relevant data for each kind of event you are waiting for, such as 124stores relevant data for each kind of event you are waiting for, such as
113the callback to call, the filehandle to watch, etc. 125the callback to call, the file handle to watch, etc.
114 126
115These watchers are normal Perl objects with normal Perl lifetime. After 127These watchers are normal Perl objects with normal Perl lifetime. After
116creating a watcher it will immediately "watch" for events and invoke the 128creating a watcher it will immediately "watch" for events and invoke the
117callback when the event occurs (of course, only when the event model 129callback when the event occurs (of course, only when the event model
118is in control). 130is in control).
227timers. 239timers.
228 240
229AnyEvent always prefers relative timers, if available, matching the 241AnyEvent always prefers relative timers, if available, matching the
230AnyEvent API. 242AnyEvent API.
231 243
244AnyEvent has two additional methods that return the "current time":
245
246=over 4
247
248=item AnyEvent->time
249
250This returns the "current wallclock time" as a fractional number of
251seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
252return, and the result is guaranteed to be compatible with those).
253
254It progresses independently of any event loop processing, i.e. each call
255will check the system clock, which usually gets updated frequently.
256
257=item AnyEvent->now
258
259This also returns the "current wallclock time", but unlike C<time>, above,
260this value might change only once per event loop iteration, depending on
261the event loop (most return the same time as C<time>, above). This is the
262time that AnyEvent's timers get scheduled against.
263
264I<In almost all cases (in all cases if you don't care), this is the
265function to call when you want to know the current time.>
266
267This function is also often faster then C<< AnyEvent->time >>, and
268thus the preferred method if you want some timestamp (for example,
269L<AnyEvent::Handle> uses this to update it's activity timeouts).
270
271The rest of this section is only of relevance if you try to be very exact
272with your timing, you can skip it without bad conscience.
273
274For a practical example of when these times differ, consider L<Event::Lib>
275and L<EV> and the following set-up:
276
277The event loop is running and has just invoked one of your callback at
278time=500 (assume no other callbacks delay processing). In your callback,
279you wait a second by executing C<sleep 1> (blocking the process for a
280second) and then (at time=501) you create a relative timer that fires
281after three seconds.
282
283With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
284both return C<501>, because that is the current time, and the timer will
285be scheduled to fire at time=504 (C<501> + C<3>).
286
287With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
288time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
289last event processing phase started. With L<EV>, your timer gets scheduled
290to run at time=503 (C<500> + C<3>).
291
292In one sense, L<Event::Lib> is more exact, as it uses the current time
293regardless of any delays introduced by event processing. However, most
294callbacks do not expect large delays in processing, so this causes a
295higher drift (and a lot more system calls to get the current time).
296
297In another sense, L<EV> is more exact, as your timer will be scheduled at
298the same time, regardless of how long event processing actually took.
299
300In either case, if you care (and in most cases, you don't), then you
301can get whatever behaviour you want with any event loop, by taking the
302difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
303account.
304
305=back
306
232=head2 SIGNAL WATCHERS 307=head2 SIGNAL WATCHERS
233 308
234You can watch for signals using a signal watcher, C<signal> is the signal 309You can watch for signals using a signal watcher, C<signal> is the signal
235I<name> without any C<SIG> prefix, C<cb> is the Perl callback to 310I<name> without any C<SIG> prefix, C<cb> is the Perl callback to
236be invoked whenever a signal occurs. 311be invoked whenever a signal occurs.
237 312
238Although the callback might get passed parameters, their value and 313Although the callback might get passed parameters, their value and
239presence is undefined and you cannot rely on them. Portable AnyEvent 314presence is undefined and you cannot rely on them. Portable AnyEvent
240callbacks cannot use arguments passed to signal watcher callbacks. 315callbacks cannot use arguments passed to signal watcher callbacks.
241 316
242Multiple signal occurances can be clumped together into one callback 317Multiple signal occurrences can be clumped together into one callback
243invocation, and callback invocation will be synchronous. synchronous means 318invocation, and callback invocation will be synchronous. Synchronous means
244that it might take a while until the signal gets handled by the process, 319that it might take a while until the signal gets handled by the process,
245but it is guarenteed not to interrupt any other callbacks. 320but it is guaranteed not to interrupt any other callbacks.
246 321
247The main advantage of using these watchers is that you can share a signal 322The main advantage of using these watchers is that you can share a signal
248between multiple watchers. 323between multiple watchers.
249 324
250This watcher might use C<%SIG>, so programs overwriting those signals 325This watcher might use C<%SIG>, so programs overwriting those signals
310Condition variables can be created by calling the C<< AnyEvent->condvar 385Condition variables can be created by calling the C<< AnyEvent->condvar
311>> method, usually without arguments. The only argument pair allowed is 386>> method, usually without arguments. The only argument pair allowed is
312C<cb>, which specifies a callback to be called when the condition variable 387C<cb>, which specifies a callback to be called when the condition variable
313becomes true. 388becomes true.
314 389
315After creation, the conditon variable is "false" until it becomes "true" 390After creation, the condition variable is "false" until it becomes "true"
316by calling the C<send> method. 391by calling the C<send> method (or calling the condition variable as if it
392were a callback, read about the caveats in the description for the C<<
393->send >> method).
317 394
318Condition variables are similar to callbacks, except that you can 395Condition variables are similar to callbacks, except that you can
319optionally wait for them. They can also be called merge points - points 396optionally wait for them. They can also be called merge points - points
320in time where multiple outstandign events have been processed. And yet 397in time where multiple outstanding events have been processed. And yet
321another way to call them is transations - each condition variable can be 398another way to call them is transactions - each condition variable can be
322used to represent a transaction, which finishes at some point and delivers 399used to represent a transaction, which finishes at some point and delivers
323a result. 400a result.
324 401
325Condition variables are very useful to signal that something has finished, 402Condition variables are very useful to signal that something has finished,
326for example, if you write a module that does asynchronous http requests, 403for example, if you write a module that does asynchronous http requests,
332you can block your main program until an event occurs - for example, you 409you can block your main program until an event occurs - for example, you
333could C<< ->recv >> in your main program until the user clicks the Quit 410could C<< ->recv >> in your main program until the user clicks the Quit
334button of your app, which would C<< ->send >> the "quit" event. 411button of your app, which would C<< ->send >> the "quit" event.
335 412
336Note that condition variables recurse into the event loop - if you have 413Note that condition variables recurse into the event loop - if you have
337two pieces of code that call C<< ->recv >> in a round-robbin fashion, you 414two pieces of code that call C<< ->recv >> in a round-robin fashion, you
338lose. Therefore, condition variables are good to export to your caller, but 415lose. Therefore, condition variables are good to export to your caller, but
339you should avoid making a blocking wait yourself, at least in callbacks, 416you should avoid making a blocking wait yourself, at least in callbacks,
340as this asks for trouble. 417as this asks for trouble.
341 418
342Condition variables are represented by hash refs in perl, and the keys 419Condition variables are represented by hash refs in perl, and the keys
347 424
348There are two "sides" to a condition variable - the "producer side" which 425There are two "sides" to a condition variable - the "producer side" which
349eventually calls C<< -> send >>, and the "consumer side", which waits 426eventually calls C<< -> send >>, and the "consumer side", which waits
350for the send to occur. 427for the send to occur.
351 428
352Example: 429Example: wait for a timer.
353 430
354 # wait till the result is ready 431 # wait till the result is ready
355 my $result_ready = AnyEvent->condvar; 432 my $result_ready = AnyEvent->condvar;
356 433
357 # do something such as adding a timer 434 # do something such as adding a timer
365 442
366 # this "blocks" (while handling events) till the callback 443 # this "blocks" (while handling events) till the callback
367 # calls send 444 # calls send
368 $result_ready->recv; 445 $result_ready->recv;
369 446
447Example: wait for a timer, but take advantage of the fact that
448condition variables are also code references.
449
450 my $done = AnyEvent->condvar;
451 my $delay = AnyEvent->timer (after => 5, cb => $done);
452 $done->recv;
453
370=head3 METHODS FOR PRODUCERS 454=head3 METHODS FOR PRODUCERS
371 455
372These methods should only be used by the producing side, i.e. the 456These methods should only be used by the producing side, i.e. the
373code/module that eventually sends the signal. Note that it is also 457code/module that eventually sends the signal. Note that it is also
374the producer side which creates the condvar in most cases, but it isn't 458the producer side which creates the condvar in most cases, but it isn't
385If a callback has been set on the condition variable, it is called 469If a callback has been set on the condition variable, it is called
386immediately from within send. 470immediately from within send.
387 471
388Any arguments passed to the C<send> call will be returned by all 472Any arguments passed to the C<send> call will be returned by all
389future C<< ->recv >> calls. 473future C<< ->recv >> calls.
474
475Condition variables are overloaded so one can call them directly
476(as a code reference). Calling them directly is the same as calling
477C<send>. Note, however, that many C-based event loops do not handle
478overloading, so as tempting as it may be, passing a condition variable
479instead of a callback does not work. Both the pure perl and EV loops
480support overloading, however, as well as all functions that use perl to
481invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
482example).
390 483
391=item $cv->croak ($error) 484=item $cv->croak ($error)
392 485
393Similar to send, but causes all call's to C<< ->recv >> to invoke 486Similar to send, but causes all call's to C<< ->recv >> to invoke
394C<Carp::croak> with the given error message/object/scalar. 487C<Carp::croak> with the given error message/object/scalar.
443doesn't execute once). 536doesn't execute once).
444 537
445This is the general pattern when you "fan out" into multiple subrequests: 538This is the general pattern when you "fan out" into multiple subrequests:
446use an outer C<begin>/C<end> pair to set the callback and ensure C<end> 539use an outer C<begin>/C<end> pair to set the callback and ensure C<end>
447is called at least once, and then, for each subrequest you start, call 540is called at least once, and then, for each subrequest you start, call
448C<begin> and for eahc subrequest you finish, call C<end>. 541C<begin> and for each subrequest you finish, call C<end>.
449 542
450=back 543=back
451 544
452=head3 METHODS FOR CONSUMERS 545=head3 METHODS FOR CONSUMERS
453 546
475(programs might want to do that to stay interactive), so I<if you are 568(programs might want to do that to stay interactive), so I<if you are
476using this from a module, never require a blocking wait>, but let the 569using this from a module, never require a blocking wait>, but let the
477caller decide whether the call will block or not (for example, by coupling 570caller decide whether the call will block or not (for example, by coupling
478condition variables with some kind of request results and supporting 571condition variables with some kind of request results and supporting
479callbacks so the caller knows that getting the result will not block, 572callbacks so the caller knows that getting the result will not block,
480while still suppporting blocking waits if the caller so desires). 573while still supporting blocking waits if the caller so desires).
481 574
482Another reason I<never> to C<< ->recv >> in a module is that you cannot 575Another reason I<never> to C<< ->recv >> in a module is that you cannot
483sensibly have two C<< ->recv >>'s in parallel, as that would require 576sensibly have two C<< ->recv >>'s in parallel, as that would require
484multiple interpreters or coroutines/threads, none of which C<AnyEvent> 577multiple interpreters or coroutines/threads, none of which C<AnyEvent>
485can supply. 578can supply.
601 694
602If it doesn't care, it can just "use AnyEvent" and use it itself, or not 695If it doesn't care, it can just "use AnyEvent" and use it itself, or not
603do anything special (it does not need to be event-based) and let AnyEvent 696do anything special (it does not need to be event-based) and let AnyEvent
604decide which implementation to chose if some module relies on it. 697decide which implementation to chose if some module relies on it.
605 698
606If the main program relies on a specific event model. For example, in 699If the main program relies on a specific event model - for example, in
607Gtk2 programs you have to rely on the Glib module. You should load the 700Gtk2 programs you have to rely on the Glib module - you should load the
608event module before loading AnyEvent or any module that uses it: generally 701event module before loading AnyEvent or any module that uses it: generally
609speaking, you should load it as early as possible. The reason is that 702speaking, you should load it as early as possible. The reason is that
610modules might create watchers when they are loaded, and AnyEvent will 703modules might create watchers when they are loaded, and AnyEvent will
611decide on the event model to use as soon as it creates watchers, and it 704decide on the event model to use as soon as it creates watchers, and it
612might chose the wrong one unless you load the correct one yourself. 705might chose the wrong one unless you load the correct one yourself.
613 706
614You can chose to use a rather inefficient pure-perl implementation by 707You can chose to use a pure-perl implementation by loading the
615loading the C<AnyEvent::Impl::Perl> module, which gives you similar 708C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
616behaviour everywhere, but letting AnyEvent chose is generally better. 709everywhere, but letting AnyEvent chose the model is generally better.
710
711=head2 MAINLOOP EMULATION
712
713Sometimes (often for short test scripts, or even standalone programs who
714only want to use AnyEvent), you do not want to run a specific event loop.
715
716In that case, you can use a condition variable like this:
717
718 AnyEvent->condvar->recv;
719
720This has the effect of entering the event loop and looping forever.
721
722Note that usually your program has some exit condition, in which case
723it is better to use the "traditional" approach of storing a condition
724variable somewhere, waiting for it, and sending it when the program should
725exit cleanly.
726
617 727
618=head1 OTHER MODULES 728=head1 OTHER MODULES
619 729
620The following is a non-exhaustive list of additional modules that use 730The following is a non-exhaustive list of additional modules that use
621AnyEvent and can therefore be mixed easily with other AnyEvent modules 731AnyEvent and can therefore be mixed easily with other AnyEvent modules
631 741
632=item L<AnyEvent::Handle> 742=item L<AnyEvent::Handle>
633 743
634Provide read and write buffers and manages watchers for reads and writes. 744Provide read and write buffers and manages watchers for reads and writes.
635 745
746=item L<AnyEvent::Socket>
747
748Provides various utility functions for (internet protocol) sockets,
749addresses and name resolution. Also functions to create non-blocking tcp
750connections or tcp servers, with IPv6 and SRV record support and more.
751
752=item L<AnyEvent::DNS>
753
754Provides rich asynchronous DNS resolver capabilities.
755
636=item L<AnyEvent::HTTPD> 756=item L<AnyEvent::HTTPD>
637 757
638Provides a simple web application server framework. 758Provides a simple web application server framework.
639
640=item L<AnyEvent::DNS>
641
642Provides asynchronous DNS resolver capabilities, beyond what
643L<AnyEvent::Util> offers.
644 759
645=item L<AnyEvent::FastPing> 760=item L<AnyEvent::FastPing>
646 761
647The fastest ping in the west. 762The fastest ping in the west.
648 763
691no warnings; 806no warnings;
692use strict; 807use strict;
693 808
694use Carp; 809use Carp;
695 810
696our $VERSION = '3.41'; 811our $VERSION = 4.11;
697our $MODEL; 812our $MODEL;
698 813
699our $AUTOLOAD; 814our $AUTOLOAD;
700our @ISA; 815our @ISA;
701 816
817our @REGISTRY;
818
819our $WIN32;
820
821BEGIN {
822 my $win32 = ! ! ($^O =~ /mswin32/i);
823 eval "sub WIN32(){ $win32 }";
824}
825
702our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 826our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
703 827
704our @REGISTRY; 828our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
829
830{
831 my $idx;
832 $PROTOCOL{$_} = ++$idx
833 for reverse split /\s*,\s*/,
834 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
835}
705 836
706my @models = ( 837my @models = (
707 [EV:: => AnyEvent::Impl::EV::], 838 [EV:: => AnyEvent::Impl::EV::],
708 [Event:: => AnyEvent::Impl::Event::], 839 [Event:: => AnyEvent::Impl::Event::],
709 [Tk:: => AnyEvent::Impl::Tk::],
710 [Wx:: => AnyEvent::Impl::POE::],
711 [Prima:: => AnyEvent::Impl::POE::],
712 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 840 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
713 # everything below here will not be autoprobed as the pureperl backend should work everywhere 841 # everything below here will not be autoprobed
714 [Glib:: => AnyEvent::Impl::Glib::], 842 # as the pureperl backend should work everywhere
843 # and is usually faster
844 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
845 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
715 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 846 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
716 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 847 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
717 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 848 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
849 [Wx:: => AnyEvent::Impl::POE::],
850 [Prima:: => AnyEvent::Impl::POE::],
718); 851);
719 852
720our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY); 853our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
721 854
722our @post_detect; 855our @post_detect;
723 856
724sub post_detect(&) { 857sub post_detect(&) {
725 my ($cb) = @_; 858 my ($cb) = @_;
730 1 863 1
731 } else { 864 } else {
732 push @post_detect, $cb; 865 push @post_detect, $cb;
733 866
734 defined wantarray 867 defined wantarray
735 ? bless \$cb, "AnyEvent::Util::Guard" 868 ? bless \$cb, "AnyEvent::Util::PostDetect"
736 : () 869 : ()
737 } 870 }
738} 871}
739 872
740sub AnyEvent::Util::Guard::DESTROY { 873sub AnyEvent::Util::PostDetect::DESTROY {
741 @post_detect = grep $_ != ${$_[0]}, @post_detect; 874 @post_detect = grep $_ != ${$_[0]}, @post_detect;
742} 875}
743 876
744sub detect() { 877sub detect() {
745 unless ($MODEL) { 878 unless ($MODEL) {
746 no strict 'refs'; 879 no strict 'refs';
880 local $SIG{__DIE__};
747 881
748 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 882 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
749 my $model = "AnyEvent::Impl::$1"; 883 my $model = "AnyEvent::Impl::$1";
750 if (eval "require $model") { 884 if (eval "require $model") {
751 $MODEL = $model; 885 $MODEL = $model;
808 $class->$func (@_); 942 $class->$func (@_);
809} 943}
810 944
811package AnyEvent::Base; 945package AnyEvent::Base;
812 946
947# default implementation for now and time
948
949use Time::HiRes ();
950
951sub time { Time::HiRes::time }
952sub now { Time::HiRes::time }
953
813# default implementation for ->condvar 954# default implementation for ->condvar
814 955
815sub condvar { 956sub condvar {
816 bless {}, AnyEvent::CondVar:: 957 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
817} 958}
818 959
819# default implementation for ->signal 960# default implementation for ->signal
820 961
821our %SIG_CB; 962our %SIG_CB;
874 or Carp::croak "required option 'pid' is missing"; 1015 or Carp::croak "required option 'pid' is missing";
875 1016
876 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1017 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
877 1018
878 unless ($WNOHANG) { 1019 unless ($WNOHANG) {
879 $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1; 1020 $WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
880 } 1021 }
881 1022
882 unless ($CHLD_W) { 1023 unless ($CHLD_W) {
883 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1024 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
884 # child could be a zombie already, so make at least one round 1025 # child could be a zombie already, so make at least one round
901 1042
902our @ISA = AnyEvent::CondVar::Base::; 1043our @ISA = AnyEvent::CondVar::Base::;
903 1044
904package AnyEvent::CondVar::Base; 1045package AnyEvent::CondVar::Base;
905 1046
1047use overload
1048 '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1049 fallback => 1;
1050
906sub _send { 1051sub _send {
907 # nop 1052 # nop
908} 1053}
909 1054
910sub send { 1055sub send {
944 $_[0]{_ae_end_cb} = $_[1] if @_ > 1; 1089 $_[0]{_ae_end_cb} = $_[1] if @_ > 1;
945} 1090}
946 1091
947sub end { 1092sub end {
948 return if --$_[0]{_ae_counter}; 1093 return if --$_[0]{_ae_counter};
949 &{ $_[0]{_ae_end_cb} } if $_[0]{_ae_end_cb}; 1094 &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
950} 1095}
951 1096
952# undocumented/compatibility with pre-3.4 1097# undocumented/compatibility with pre-3.4
953*broadcast = \&send; 1098*broadcast = \&send;
954*wait = \&_wait; 1099*wait = \&_wait;
1016model it chooses. 1161model it chooses.
1017 1162
1018=item C<PERL_ANYEVENT_MODEL> 1163=item C<PERL_ANYEVENT_MODEL>
1019 1164
1020This can be used to specify the event model to be used by AnyEvent, before 1165This can be used to specify the event model to be used by AnyEvent, before
1021autodetection and -probing kicks in. It must be a string consisting 1166auto detection and -probing kicks in. It must be a string consisting
1022entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended 1167entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1023and the resulting module name is loaded and if the load was successful, 1168and the resulting module name is loaded and if the load was successful,
1024used as event model. If it fails to load AnyEvent will proceed with 1169used as event model. If it fails to load AnyEvent will proceed with
1025autodetection and -probing. 1170auto detection and -probing.
1026 1171
1027This functionality might change in future versions. 1172This functionality might change in future versions.
1028 1173
1029For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you 1174For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1030could start your program like this: 1175could start your program like this:
1031 1176
1032 PERL_ANYEVENT_MODEL=Perl perl ... 1177 PERL_ANYEVENT_MODEL=Perl perl ...
1178
1179=item C<PERL_ANYEVENT_PROTOCOLS>
1180
1181Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1182for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1183of auto probing).
1184
1185Must be set to a comma-separated list of protocols or address families,
1186current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1187used, and preference will be given to protocols mentioned earlier in the
1188list.
1189
1190This variable can effectively be used for denial-of-service attacks
1191against local programs (e.g. when setuid), although the impact is likely
1192small, as the program has to handle connection errors already-
1193
1194Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1195but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1196- only support IPv4, never try to resolve or contact IPv6
1197addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1198IPv6, but prefer IPv6 over IPv4.
1199
1200=item C<PERL_ANYEVENT_EDNS0>
1201
1202Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1203for DNS. This extension is generally useful to reduce DNS traffic, but
1204some (broken) firewalls drop such DNS packets, which is why it is off by
1205default.
1206
1207Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1208EDNS0 in its DNS requests.
1209
1210=item C<PERL_ANYEVENT_MAX_FORKS>
1211
1212The maximum number of child processes that C<AnyEvent::Util::fork_call>
1213will create in parallel.
1033 1214
1034=back 1215=back
1035 1216
1036=head1 EXAMPLE PROGRAM 1217=head1 EXAMPLE PROGRAM
1037 1218
1048 poll => 'r', 1229 poll => 'r',
1049 cb => sub { 1230 cb => sub {
1050 warn "io event <$_[0]>\n"; # will always output <r> 1231 warn "io event <$_[0]>\n"; # will always output <r>
1051 chomp (my $input = <STDIN>); # read a line 1232 chomp (my $input = <STDIN>); # read a line
1052 warn "read: $input\n"; # output what has been read 1233 warn "read: $input\n"; # output what has been read
1053 $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i 1234 $cv->send if $input =~ /^q/i; # quit program if /^q/i
1054 }, 1235 },
1055 ); 1236 );
1056 1237
1057 my $time_watcher; # can only be used once 1238 my $time_watcher; # can only be used once
1058 1239
1063 }); 1244 });
1064 } 1245 }
1065 1246
1066 new_timer; # create first timer 1247 new_timer; # create first timer
1067 1248
1068 $cv->wait; # wait until user enters /^q/i 1249 $cv->recv; # wait until user enters /^q/i
1069 1250
1070=head1 REAL-WORLD EXAMPLE 1251=head1 REAL-WORLD EXAMPLE
1071 1252
1072Consider the L<Net::FCP> module. It features (among others) the following 1253Consider the L<Net::FCP> module. It features (among others) the following
1073API calls, which are to freenet what HTTP GET requests are to http: 1254API calls, which are to freenet what HTTP GET requests are to http:
1123 syswrite $txn->{fh}, $txn->{request} 1304 syswrite $txn->{fh}, $txn->{request}
1124 or die "connection or write error"; 1305 or die "connection or write error";
1125 $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); 1306 $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1126 1307
1127Again, C<fh_ready_r> waits till all data has arrived, and then stores the 1308Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1128result and signals any possible waiters that the request ahs finished: 1309result and signals any possible waiters that the request has finished:
1129 1310
1130 sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; 1311 sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1131 1312
1132 if (end-of-file or data complete) { 1313 if (end-of-file or data complete) {
1133 $txn->{result} = $txn->{buf}; 1314 $txn->{result} = $txn->{buf};
1134 $txn->{finished}->broadcast; 1315 $txn->{finished}->send;
1135 $txb->{cb}->($txn) of $txn->{cb}; # also call callback 1316 $txb->{cb}->($txn) of $txn->{cb}; # also call callback
1136 } 1317 }
1137 1318
1138The C<result> method, finally, just waits for the finished signal (if the 1319The C<result> method, finally, just waits for the finished signal (if the
1139request was already finished, it doesn't wait, of course, and returns the 1320request was already finished, it doesn't wait, of course, and returns the
1140data: 1321data:
1141 1322
1142 $txn->{finished}->wait; 1323 $txn->{finished}->recv;
1143 return $txn->{result}; 1324 return $txn->{result};
1144 1325
1145The actual code goes further and collects all errors (C<die>s, exceptions) 1326The actual code goes further and collects all errors (C<die>s, exceptions)
1146that occured during request processing. The C<result> method detects 1327that occurred during request processing. The C<result> method detects
1147whether an exception as thrown (it is stored inside the $txn object) 1328whether an exception as thrown (it is stored inside the $txn object)
1148and just throws the exception, which means connection errors and other 1329and just throws the exception, which means connection errors and other
1149problems get reported tot he code that tries to use the result, not in a 1330problems get reported tot he code that tries to use the result, not in a
1150random callback. 1331random callback.
1151 1332
1182 1363
1183 my $quit = AnyEvent->condvar; 1364 my $quit = AnyEvent->condvar;
1184 1365
1185 $fcp->txn_client_get ($url)->cb (sub { 1366 $fcp->txn_client_get ($url)->cb (sub {
1186 ... 1367 ...
1187 $quit->broadcast; 1368 $quit->send;
1188 }); 1369 });
1189 1370
1190 $quit->wait; 1371 $quit->recv;
1191 1372
1192 1373
1193=head1 BENCHMARKS 1374=head1 BENCHMARKS
1194 1375
1195To give you an idea of the performance and overheads that AnyEvent adds 1376To give you an idea of the performance and overheads that AnyEvent adds
1197of various event loops I prepared some benchmarks. 1378of various event loops I prepared some benchmarks.
1198 1379
1199=head2 BENCHMARKING ANYEVENT OVERHEAD 1380=head2 BENCHMARKING ANYEVENT OVERHEAD
1200 1381
1201Here is a benchmark of various supported event models used natively and 1382Here is a benchmark of various supported event models used natively and
1202through anyevent. The benchmark creates a lot of timers (with a zero 1383through AnyEvent. The benchmark creates a lot of timers (with a zero
1203timeout) and I/O watchers (watching STDOUT, a pty, to become writable, 1384timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1204which it is), lets them fire exactly once and destroys them again. 1385which it is), lets them fire exactly once and destroys them again.
1205 1386
1206Source code for this benchmark is found as F<eg/bench> in the AnyEvent 1387Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1207distribution. 1388distribution.
1224all watchers, to avoid adding memory overhead. That means closure creation 1405all watchers, to avoid adding memory overhead. That means closure creation
1225and memory usage is not included in the figures. 1406and memory usage is not included in the figures.
1226 1407
1227I<invoke> is the time, in microseconds, used to invoke a simple 1408I<invoke> is the time, in microseconds, used to invoke a simple
1228callback. The callback simply counts down a Perl variable and after it was 1409callback. The callback simply counts down a Perl variable and after it was
1229invoked "watcher" times, it would C<< ->broadcast >> a condvar once to 1410invoked "watcher" times, it would C<< ->send >> a condvar once to
1230signal the end of this phase. 1411signal the end of this phase.
1231 1412
1232I<destroy> is the time, in microseconds, that it takes to destroy a single 1413I<destroy> is the time, in microseconds, that it takes to destroy a single
1233watcher. 1414watcher.
1234 1415
1330 1511
1331=back 1512=back
1332 1513
1333=head2 BENCHMARKING THE LARGE SERVER CASE 1514=head2 BENCHMARKING THE LARGE SERVER CASE
1334 1515
1335This benchmark atcually benchmarks the event loop itself. It works by 1516This benchmark actually benchmarks the event loop itself. It works by
1336creating a number of "servers": each server consists of a socketpair, a 1517creating a number of "servers": each server consists of a socket pair, a
1337timeout watcher that gets reset on activity (but never fires), and an I/O 1518timeout watcher that gets reset on activity (but never fires), and an I/O
1338watcher waiting for input on one side of the socket. Each time the socket 1519watcher waiting for input on one side of the socket. Each time the socket
1339watcher reads a byte it will write that byte to a random other "server". 1520watcher reads a byte it will write that byte to a random other "server".
1340 1521
1341The effect is that there will be a lot of I/O watchers, only part of which 1522The effect is that there will be a lot of I/O watchers, only part of which
1342are active at any one point (so there is a constant number of active 1523are active at any one point (so there is a constant number of active
1343fds for each loop iterstaion, but which fds these are is random). The 1524fds for each loop iteration, but which fds these are is random). The
1344timeout is reset each time something is read because that reflects how 1525timeout is reset each time something is read because that reflects how
1345most timeouts work (and puts extra pressure on the event loops). 1526most timeouts work (and puts extra pressure on the event loops).
1346 1527
1347In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100 1528In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1348(1%) are active. This mirrors the activity of large servers with many 1529(1%) are active. This mirrors the activity of large servers with many
1349connections, most of which are idle at any one point in time. 1530connections, most of which are idle at any one point in time.
1350 1531
1351Source code for this benchmark is found as F<eg/bench2> in the AnyEvent 1532Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1352distribution. 1533distribution.
1354=head3 Explanation of the columns 1535=head3 Explanation of the columns
1355 1536
1356I<sockets> is the number of sockets, and twice the number of "servers" (as 1537I<sockets> is the number of sockets, and twice the number of "servers" (as
1357each server has a read and write socket end). 1538each server has a read and write socket end).
1358 1539
1359I<create> is the time it takes to create a socketpair (which is 1540I<create> is the time it takes to create a socket pair (which is
1360nontrivial) and two watchers: an I/O watcher and a timeout watcher. 1541nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1361 1542
1362I<request>, the most important value, is the time it takes to handle a 1543I<request>, the most important value, is the time it takes to handle a
1363single "request", that is, reading the token from the pipe and forwarding 1544single "request", that is, reading the token from the pipe and forwarding
1364it to another server. This includes deleting the old timeout and creating 1545it to another server. This includes deleting the old timeout and creating
1437speed most when you have lots of watchers, not when you only have a few of 1618speed most when you have lots of watchers, not when you only have a few of
1438them). 1619them).
1439 1620
1440EV is again fastest. 1621EV is again fastest.
1441 1622
1442Perl again comes second. It is noticably faster than the C-based event 1623Perl again comes second. It is noticeably faster than the C-based event
1443loops Event and Glib, although the difference is too small to really 1624loops Event and Glib, although the difference is too small to really
1444matter. 1625matter.
1445 1626
1446POE also performs much better in this case, but is is still far behind the 1627POE also performs much better in this case, but is is still far behind the
1447others. 1628others.
1487probably even less useful to an attacker than PERL_ANYEVENT_MODEL). 1668probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
1488 1669
1489 1670
1490=head1 SEE ALSO 1671=head1 SEE ALSO
1491 1672
1673Utility functions: L<AnyEvent::Util>.
1674
1492Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, 1675Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1493L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 1676L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1494 1677
1495Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 1678Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1496L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 1679L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1497L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 1680L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1498L<AnyEvent::Impl::POE>. 1681L<AnyEvent::Impl::POE>.
1499 1682
1683Non-blocking file handles, sockets, TCP clients and
1684servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
1685
1686Asynchronous DNS: L<AnyEvent::DNS>.
1687
1500Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, 1688Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
1501 1689
1502Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. 1690Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1503 1691
1504 1692
1505=head1 AUTHOR 1693=head1 AUTHOR
1506 1694
1507 Marc Lehmann <schmorp@schmorp.de> 1695 Marc Lehmann <schmorp@schmorp.de>

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