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Revision 1.140 by root, Mon May 26 06:18:53 2008 UTC vs.
Revision 1.152 by root, Tue Jun 3 09:02:46 2008 UTC

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
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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).
… …
62modules, you get an enormous 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
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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
… …
126Many watchers either are used with "recursion" (repeating timers for 138Many watchers either are used with "recursion" (repeating timers for
127example), or need to refer to their watcher object in other ways. 139example), or need to refer to their watcher object in other ways.
128 140
129An any way to achieve that is this pattern: 141An any way to achieve that is this pattern:
130 142
131 my $w; $w = AnyEvent->type (arg => value ..., cb => sub { 143 my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
132 # you can use $w here, for example to undef it 144 # you can use $w here, for example to undef it
133 undef $w; 145 undef $w;
134 }); 146 });
135 147
136Note that C<my $w; $w => combination. This is necessary because in Perl, 148Note that C<my $w; $w => combination. This is necessary because in Perl,
137my variables are only visible after the statement in which they are 149my variables are only visible after the statement in which they are
138declared. 150declared.
139 151
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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.
… …
277AnyEvent program, you I<have> to create at least one watcher before you 352AnyEvent program, you I<have> to create at least one watcher before you
278C<fork> the child (alternatively, you can call C<AnyEvent::detect>). 353C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
279 354
280Example: fork a process and wait for it 355Example: fork a process and wait for it
281 356
282 my $done = AnyEvent->condvar; 357 my $done = AnyEvent->condvar;
283 358
284 my $pid = fork or exit 5; 359 my $pid = fork or exit 5;
285 360
286 my $w = AnyEvent->child ( 361 my $w = AnyEvent->child (
287 pid => $pid, 362 pid => $pid,
288 cb => sub { 363 cb => sub {
289 my ($pid, $status) = @_; 364 my ($pid, $status) = @_;
290 warn "pid $pid exited with status $status"; 365 warn "pid $pid exited with status $status";
291 $done->send; 366 $done->send;
292 }, 367 },
293 ); 368 );
294 369
295 # do something else, then wait for process exit 370 # do something else, then wait for process exit
296 $done->recv; 371 $done->recv;
297 372
298=head2 CONDITION VARIABLES 373=head2 CONDITION VARIABLES
299 374
300If you are familiar with some event loops you will know that all of them 375If you are familiar with some event loops you will know that all of them
301require you to run some blocking "loop", "run" or similar function that 376require you to run some blocking "loop", "run" or similar function that
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522 597
523This is a mutator function that returns the callback set and optionally 598This is a mutator function that returns the callback set and optionally
524replaces it before doing so. 599replaces it before doing so.
525 600
526The callback will be called when the condition becomes "true", i.e. when 601The callback will be called when the condition becomes "true", i.e. when
527C<send> or C<croak> are called. Calling C<recv> inside the callback 602C<send> or C<croak> are called, with the only argument being the condition
528or at any later time is guaranteed not to block. 603variable itself. Calling C<recv> inside the callback or at any later time
604is guaranteed not to block.
529 605
530=back 606=back
531 607
532=head1 GLOBAL VARIABLES AND FUNCTIONS 608=head1 GLOBAL VARIABLES AND FUNCTIONS
533 609
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731no warnings; 807no warnings;
732use strict; 808use strict;
733 809
734use Carp; 810use Carp;
735 811
736our $VERSION = '4.04'; 812our $VERSION = 4.12;
737our $MODEL; 813our $MODEL;
738 814
739our $AUTOLOAD; 815our $AUTOLOAD;
740our @ISA; 816our @ISA;
741 817
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773 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 849 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
774 [Wx:: => AnyEvent::Impl::POE::], 850 [Wx:: => AnyEvent::Impl::POE::],
775 [Prima:: => AnyEvent::Impl::POE::], 851 [Prima:: => AnyEvent::Impl::POE::],
776); 852);
777 853
778our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY); 854our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
779 855
780our @post_detect; 856our @post_detect;
781 857
782sub post_detect(&) { 858sub post_detect(&) {
783 my ($cb) = @_; 859 my ($cb) = @_;
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867 $class->$func (@_); 943 $class->$func (@_);
868} 944}
869 945
870package AnyEvent::Base; 946package AnyEvent::Base;
871 947
948# default implementation for now and time
949
950use Time::HiRes ();
951
952sub time { Time::HiRes::time }
953sub now { Time::HiRes::time }
954
872# default implementation for ->condvar 955# default implementation for ->condvar
873 956
874sub condvar { 957sub condvar {
875 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: 958 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
876} 959}
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1090This functionality might change in future versions. 1173This functionality might change in future versions.
1091 1174
1092For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you 1175For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1093could start your program like this: 1176could start your program like this:
1094 1177
1095 PERL_ANYEVENT_MODEL=Perl perl ... 1178 PERL_ANYEVENT_MODEL=Perl perl ...
1096 1179
1097=item C<PERL_ANYEVENT_PROTOCOLS> 1180=item C<PERL_ANYEVENT_PROTOCOLS>
1098 1181
1099Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences 1182Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1100for IPv4 or IPv6. The default is unspecified (and might change, or be the result 1183for IPv4 or IPv6. The default is unspecified (and might change, or be the result
… …
1122some (broken) firewalls drop such DNS packets, which is why it is off by 1205some (broken) firewalls drop such DNS packets, which is why it is off by
1123default. 1206default.
1124 1207
1125Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce 1208Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1126EDNS0 in its DNS requests. 1209EDNS0 in its DNS requests.
1210
1211=item C<PERL_ANYEVENT_MAX_FORKS>
1212
1213The maximum number of child processes that C<AnyEvent::Util::fork_call>
1214will create in parallel.
1127 1215
1128=back 1216=back
1129 1217
1130=head1 EXAMPLE PROGRAM 1218=head1 EXAMPLE PROGRAM
1131 1219
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1570specified in the variable. 1658specified in the variable.
1571 1659
1572You can make AnyEvent completely ignore this variable by deleting it 1660You can make AnyEvent completely ignore this variable by deleting it
1573before the first watcher gets created, e.g. with a C<BEGIN> block: 1661before the first watcher gets created, e.g. with a C<BEGIN> block:
1574 1662
1575 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } 1663 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1576 1664
1577 use AnyEvent; 1665 use AnyEvent;
1578 1666
1579Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can 1667Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1580be used to probe what backend is used and gain other information (which is 1668be used to probe what backend is used and gain other information (which is
1581probably even less useful to an attacker than PERL_ANYEVENT_MODEL). 1669probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
1582 1670
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1603Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 1691Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1604 1692
1605 1693
1606=head1 AUTHOR 1694=head1 AUTHOR
1607 1695
1608 Marc Lehmann <schmorp@schmorp.de> 1696 Marc Lehmann <schmorp@schmorp.de>
1609 http://home.schmorp.de/ 1697 http://home.schmorp.de/
1610 1698
1611=cut 1699=cut
1612 1700
16131 17011
1614 1702

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