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Revision 1.131 by root, Sat May 24 17:48:38 2008 UTC vs.
Revision 1.145 by root, Thu May 29 03:45:37 2008 UTC

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48isn't itself. What's worse, all the potential users of your module are 48isn't itself. What's worse, all the potential users of your module are
49I<also> forced to use the same event loop you use. 49I<also> forced to use the same event loop you use.
50 50
51AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works 51AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52fine. AnyEvent + Tk works fine etc. etc. but none of these work together 52fine. 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 53with 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, 54your 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 55too. But if your module uses AnyEvent, it works transparently with all
56event models it supports (including stuff like POE and IO::Async, as long 56event 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 57as those use one of the supported event loops. It is trivial to add new
58event loops to AnyEvent, too, so it is future-proof). 58event loops to AnyEvent, too, so it is future-proof).
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62modules, you get an enormous amount of code and strict rules you have to 62modules, 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 63follow. 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 64offering the functionality that is necessary, in as thin as a wrapper as
65technically possible. 65technically possible.
66 66
67Of course, AnyEvent comes with a big (and fully optional!) toolbox
68of useful functionality, such as an asynchronous DNS resolver, 100%
69non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
70such as Windows) and lots of real-world knowledge and workarounds for
71platform bugs and differences.
72
67Of course, if you want lots of policy (this can arguably be somewhat 73Now, 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 74useful) and you want to force your users to use the one and only event
69model, you should I<not> use this module. 75model, you should I<not> use this module.
70 76
71=head1 DESCRIPTION 77=head1 DESCRIPTION
72 78
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102starts using it, all bets are off. Maybe you should tell their authors to 108starts using it, all bets are off. Maybe you should tell their authors to
103use AnyEvent so their modules work together with others seamlessly... 109use AnyEvent so their modules work together with others seamlessly...
104 110
105The pure-perl implementation of AnyEvent is called 111The pure-perl implementation of AnyEvent is called
106C<AnyEvent::Impl::Perl>. Like other event modules you can load it 112C<AnyEvent::Impl::Perl>. Like other event modules you can load it
107explicitly. 113explicitly and enjoy the high availability of that event loop :)
108 114
109=head1 WATCHERS 115=head1 WATCHERS
110 116
111AnyEvent has the central concept of a I<watcher>, which is an object that 117AnyEvent 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 118stores relevant data for each kind of event you are waiting for, such as
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226on true relative time) and absolute (ev_periodic, based on wallclock time) 232on true relative time) and absolute (ev_periodic, based on wallclock time)
227timers. 233timers.
228 234
229AnyEvent always prefers relative timers, if available, matching the 235AnyEvent always prefers relative timers, if available, matching the
230AnyEvent API. 236AnyEvent API.
237
238AnyEvent has two additional methods that return the "current time":
239
240=over 4
241
242=item AnyEvent->time
243
244This returns the "current wallclock time" as a fractional number of
245seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
246return, and the result is guaranteed to be compatible with those).
247
248It progresses independently of any event loop processing, i.e. each call
249will check the system clock, which usually gets updated frequently.
250
251=item AnyEvent->now
252
253This also returns the "current wallclock time", but unlike C<time>, above,
254this value might change only once per event loop iteration, depending on
255the event loop (most return the same time as C<time>, above). This is the
256time that AnyEvent's timers get scheduled against.
257
258I<In almost all cases (in all cases if you don't care), this is the
259function to call when you want to know the current time.>
260
261This function is also often faster then C<< AnyEvent->time >>, and
262thus the preferred method if you want some timestamp (for example,
263L<AnyEvent::Handle> uses this to update it's activity timeouts).
264
265The rest of this section is only of relevance if you try to be very exact
266with your timing, you can skip it without bad conscience.
267
268For a practical example of when these times differ, consider L<Event::Lib>
269and L<EV> and the following set-up:
270
271The event loop is running and has just invoked one of your callback at
272time=500 (assume no other callbacks delay processing). In your callback,
273you wait a second by executing C<sleep 1> (blocking the process for a
274second) and then (at time=501) you create a relative timer that fires
275after three seconds.
276
277With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
278both return C<501>, because that is the current time, and the timer will
279be scheduled to fire at time=504 (C<501> + C<3>).
280
281With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
282time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
283last event processing phase started. With L<EV>, your timer gets scheduled
284to run at time=503 (C<500> + C<3>).
285
286In one sense, L<Event::Lib> is more exact, as it uses the current time
287regardless of any delays introduced by event processing. However, most
288callbacks do not expect large delays in processing, so this causes a
289higher drift (and a lot more system calls to get the current time).
290
291In another sense, L<EV> is more exact, as your timer will be scheduled at
292the same time, regardless of how long event processing actually took.
293
294In either case, if you care (and in most cases, you don't), then you
295can get whatever behaviour you want with any event loop, by taking the
296difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
297account.
298
299=back
231 300
232=head2 SIGNAL WATCHERS 301=head2 SIGNAL WATCHERS
233 302
234You can watch for signals using a signal watcher, C<signal> is the signal 303You 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 304I<name> without any C<SIG> prefix, C<cb> is the Perl callback to
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312C<cb>, which specifies a callback to be called when the condition variable 381C<cb>, which specifies a callback to be called when the condition variable
313becomes true. 382becomes true.
314 383
315After creation, the condition variable is "false" until it becomes "true" 384After creation, the condition variable is "false" until it becomes "true"
316by calling the C<send> method (or calling the condition variable as if it 385by calling the C<send> method (or calling the condition variable as if it
317were a callback). 386were a callback, read about the caveats in the description for the C<<
387->send >> method).
318 388
319Condition variables are similar to callbacks, except that you can 389Condition variables are similar to callbacks, except that you can
320optionally wait for them. They can also be called merge points - points 390optionally wait for them. They can also be called merge points - points
321in time where multiple outstanding events have been processed. And yet 391in time where multiple outstanding events have been processed. And yet
322another way to call them is transactions - each condition variable can be 392another way to call them is transactions - each condition variable can be
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394immediately from within send. 464immediately from within send.
395 465
396Any arguments passed to the C<send> call will be returned by all 466Any arguments passed to the C<send> call will be returned by all
397future C<< ->recv >> calls. 467future C<< ->recv >> calls.
398 468
399Condition variables are overloaded so one can call them directly (as a 469Condition variables are overloaded so one can call them directly
400code reference). Calling them directly is the same as calling C<send>. 470(as a code reference). Calling them directly is the same as calling
471C<send>. Note, however, that many C-based event loops do not handle
472overloading, so as tempting as it may be, passing a condition variable
473instead of a callback does not work. Both the pure perl and EV loops
474support overloading, however, as well as all functions that use perl to
475invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
476example).
401 477
402=item $cv->croak ($error) 478=item $cv->croak ($error)
403 479
404Similar to send, but causes all call's to C<< ->recv >> to invoke 480Similar to send, but causes all call's to C<< ->recv >> to invoke
405C<Carp::croak> with the given error message/object/scalar. 481C<Carp::croak> with the given error message/object/scalar.
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612 688
613If it doesn't care, it can just "use AnyEvent" and use it itself, or not 689If it doesn't care, it can just "use AnyEvent" and use it itself, or not
614do anything special (it does not need to be event-based) and let AnyEvent 690do anything special (it does not need to be event-based) and let AnyEvent
615decide which implementation to chose if some module relies on it. 691decide which implementation to chose if some module relies on it.
616 692
617If the main program relies on a specific event model. For example, in 693If the main program relies on a specific event model - for example, in
618Gtk2 programs you have to rely on the Glib module. You should load the 694Gtk2 programs you have to rely on the Glib module - you should load the
619event module before loading AnyEvent or any module that uses it: generally 695event module before loading AnyEvent or any module that uses it: generally
620speaking, you should load it as early as possible. The reason is that 696speaking, you should load it as early as possible. The reason is that
621modules might create watchers when they are loaded, and AnyEvent will 697modules might create watchers when they are loaded, and AnyEvent will
622decide on the event model to use as soon as it creates watchers, and it 698decide on the event model to use as soon as it creates watchers, and it
623might chose the wrong one unless you load the correct one yourself. 699might chose the wrong one unless you load the correct one yourself.
624 700
625You can chose to use a rather inefficient pure-perl implementation by 701You can chose to use a pure-perl implementation by loading the
626loading the C<AnyEvent::Impl::Perl> module, which gives you similar 702C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
627behaviour everywhere, but letting AnyEvent chose is generally better. 703everywhere, but letting AnyEvent chose the model is generally better.
704
705=head2 MAINLOOP EMULATION
706
707Sometimes (often for short test scripts, or even standalone programs who
708only want to use AnyEvent), you do not want to run a specific event loop.
709
710In that case, you can use a condition variable like this:
711
712 AnyEvent->condvar->recv;
713
714This has the effect of entering the event loop and looping forever.
715
716Note that usually your program has some exit condition, in which case
717it is better to use the "traditional" approach of storing a condition
718variable somewhere, waiting for it, and sending it when the program should
719exit cleanly.
720
628 721
629=head1 OTHER MODULES 722=head1 OTHER MODULES
630 723
631The following is a non-exhaustive list of additional modules that use 724The following is a non-exhaustive list of additional modules that use
632AnyEvent and can therefore be mixed easily with other AnyEvent modules 725AnyEvent and can therefore be mixed easily with other AnyEvent modules
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648 741
649Provides various utility functions for (internet protocol) sockets, 742Provides various utility functions for (internet protocol) sockets,
650addresses and name resolution. Also functions to create non-blocking tcp 743addresses and name resolution. Also functions to create non-blocking tcp
651connections or tcp servers, with IPv6 and SRV record support and more. 744connections or tcp servers, with IPv6 and SRV record support and more.
652 745
746=item L<AnyEvent::DNS>
747
748Provides rich asynchronous DNS resolver capabilities.
749
653=item L<AnyEvent::HTTPD> 750=item L<AnyEvent::HTTPD>
654 751
655Provides a simple web application server framework. 752Provides a simple web application server framework.
656
657=item L<AnyEvent::DNS>
658
659Provides rich asynchronous DNS resolver capabilities.
660 753
661=item L<AnyEvent::FastPing> 754=item L<AnyEvent::FastPing>
662 755
663The fastest ping in the west. 756The fastest ping in the west.
664 757
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707no warnings; 800no warnings;
708use strict; 801use strict;
709 802
710use Carp; 803use Carp;
711 804
712our $VERSION = '4.0'; 805our $VERSION = '4.1';
713our $MODEL; 806our $MODEL;
714 807
715our $AUTOLOAD; 808our $AUTOLOAD;
716our @ISA; 809our @ISA;
717 810
811our @REGISTRY;
812
813our $WIN32;
814
815BEGIN {
816 my $win32 = ! ! ($^O =~ /mswin32/i);
817 eval "sub WIN32(){ $win32 }";
818}
819
718our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 820our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
719 821
720our @REGISTRY; 822our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
721
722our %PROTOCOL; # (ipv4|ipv6) => (1|2)
723 823
724{ 824{
725 my $idx; 825 my $idx;
726 $PROTOCOL{$_} = ++$idx 826 $PROTOCOL{$_} = ++$idx
827 for reverse split /\s*,\s*/,
727 for split /\s*,\s*/, $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; 828 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
728} 829}
729 830
730my @models = ( 831my @models = (
731 [EV:: => AnyEvent::Impl::EV::], 832 [EV:: => AnyEvent::Impl::EV::],
732 [Event:: => AnyEvent::Impl::Event::], 833 [Event:: => AnyEvent::Impl::Event::],
733 [Tk:: => AnyEvent::Impl::Tk::],
734 [Wx:: => AnyEvent::Impl::POE::],
735 [Prima:: => AnyEvent::Impl::POE::],
736 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 834 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
737 # everything below here will not be autoprobed as the pureperl backend should work everywhere 835 # everything below here will not be autoprobed
738 [Glib:: => AnyEvent::Impl::Glib::], 836 # as the pureperl backend should work everywhere
837 # and is usually faster
838 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
839 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
739 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 840 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
740 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 841 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
741 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 842 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
843 [Wx:: => AnyEvent::Impl::POE::],
844 [Prima:: => AnyEvent::Impl::POE::],
742); 845);
743 846
744our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY); 847our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
745 848
746our @post_detect; 849our @post_detect;
747 850
748sub post_detect(&) { 851sub post_detect(&) {
749 my ($cb) = @_; 852 my ($cb) = @_;
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766} 869}
767 870
768sub detect() { 871sub detect() {
769 unless ($MODEL) { 872 unless ($MODEL) {
770 no strict 'refs'; 873 no strict 'refs';
874 local $SIG{__DIE__};
771 875
772 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 876 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
773 my $model = "AnyEvent::Impl::$1"; 877 my $model = "AnyEvent::Impl::$1";
774 if (eval "require $model") { 878 if (eval "require $model") {
775 $MODEL = $model; 879 $MODEL = $model;
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832 $class->$func (@_); 936 $class->$func (@_);
833} 937}
834 938
835package AnyEvent::Base; 939package AnyEvent::Base;
836 940
941# default implementation for now and time
942
943use Time::HiRes ();
944
945sub time { Time::HiRes::time }
946sub now { Time::HiRes::time }
947
837# default implementation for ->condvar 948# default implementation for ->condvar
838 949
839sub condvar { 950sub condvar {
840 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: 951 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
841} 952}
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898 or Carp::croak "required option 'pid' is missing"; 1009 or Carp::croak "required option 'pid' is missing";
899 1010
900 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1011 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
901 1012
902 unless ($WNOHANG) { 1013 unless ($WNOHANG) {
903 $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1; 1014 $WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
904 } 1015 }
905 1016
906 unless ($CHLD_W) { 1017 unless ($CHLD_W) {
907 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1018 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
908 # child could be a zombie already, so make at least one round 1019 # child could be a zombie already, so make at least one round
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1087some (broken) firewalls drop such DNS packets, which is why it is off by 1198some (broken) firewalls drop such DNS packets, which is why it is off by
1088default. 1199default.
1089 1200
1090Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce 1201Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1091EDNS0 in its DNS requests. 1202EDNS0 in its DNS requests.
1203
1204=item C<PERL_ANYEVENT_MAX_FORKS>
1205
1206The maximum number of child processes that C<AnyEvent::Util::fork_call>
1207will create in parallel.
1092 1208
1093=back 1209=back
1094 1210
1095=head1 EXAMPLE PROGRAM 1211=head1 EXAMPLE PROGRAM
1096 1212

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