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Revision 1.143 by root, Wed May 28 23:57:38 2008 UTC vs.
Revision 1.151 by root, Sat May 31 13:38:01 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
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?
132Many watchers either are used with "recursion" (repeating timers for 138Many watchers either are used with "recursion" (repeating timers for
133example), or need to refer to their watcher object in other ways. 139example), or need to refer to their watcher object in other ways.
134 140
135An any way to achieve that is this pattern: 141An any way to achieve that is this pattern:
136 142
137 my $w; $w = AnyEvent->type (arg => value ..., cb => sub { 143 my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
138 # you can use $w here, for example to undef it 144 # you can use $w here, for example to undef it
139 undef $w; 145 undef $w;
140 }); 146 });
141 147
142Note 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,
143my variables are only visible after the statement in which they are 149my variables are only visible after the statement in which they are
144declared. 150declared.
145 151
243 249
244This returns the "current wallclock time" as a fractional number of 250This 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> 251seconds 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). 252return, and the result is guaranteed to be compatible with those).
247 253
248It progresses independently of any event loop processing. 254It progresses independently of any event loop processing, i.e. each call
249 255will check the system clock, which usually gets updated frequently.
250In almost all cases (in all cases if you don't care), this is the function
251to call when you want to know the current time.
252 256
253=item AnyEvent->now 257=item AnyEvent->now
254 258
255This also returns the "current wallclock time", but unlike C<time>, above, 259This also returns the "current wallclock time", but unlike C<time>, above,
256this value might change only once per event loop iteration, depending on 260this value might change only once per event loop iteration, depending on
257the event loop (most return the same time as C<time>, above). This is the 261the event loop (most return the same time as C<time>, above). This is the
258time that AnyEvent timers get scheduled against. 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.
259 273
260For a practical example of when these times differ, consider L<Event::Lib> 274For a practical example of when these times differ, consider L<Event::Lib>
261and L<EV> and the following set-up: 275and L<EV> and the following set-up:
262 276
263The event loop is running and has just invoked one of your callback at 277The event loop is running and has just invoked one of your callback at
268 282
269With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will 283With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
270both return C<501>, because that is the current time, and the timer will 284both return C<501>, because that is the current time, and the timer will
271be scheduled to fire at time=504 (C<501> + C<3>). 285be scheduled to fire at time=504 (C<501> + C<3>).
272 286
273With L<EV>m C<< AnyEvent->time >> returns C<501> (as that is the current 287With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
274time), but C<< AnyEvent->now >> returns C<500>, as that is the time the 288time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
275last event processing phase started. With L<EV>, your timer gets scheduled 289last event processing phase started. With L<EV>, your timer gets scheduled
276to run at time=503 (C<500> + C<3>). 290to run at time=503 (C<500> + C<3>).
277 291
278In one sense, L<Event::Lib> is more exact, as it uses the current time 292In one sense, L<Event::Lib> is more exact, as it uses the current time
279regardless of any delays introduced by event processing. However, most 293regardless of any delays introduced by event processing. However, most
280callbacks do not expect large delays in processing, so this causes a 294callbacks do not expect large delays in processing, so this causes a
281higher drift (and a lot more syscalls to get the current time). 295higher drift (and a lot more system calls to get the current time).
282 296
283In another sense, L<EV> is more exact, as your timer will be scheduled at 297In another sense, L<EV> is more exact, as your timer will be scheduled at
284the same time, regardless of how long event processing actually took. 298the same time, regardless of how long event processing actually took.
285 299
286In either case, if you care (and in most cases, you don't), then you 300In either case, if you care (and in most cases, you don't), then you
338AnyEvent 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
339C<fork> the child (alternatively, you can call C<AnyEvent::detect>). 353C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
340 354
341Example: fork a process and wait for it 355Example: fork a process and wait for it
342 356
343 my $done = AnyEvent->condvar; 357 my $done = AnyEvent->condvar;
344 358
345 my $pid = fork or exit 5; 359 my $pid = fork or exit 5;
346 360
347 my $w = AnyEvent->child ( 361 my $w = AnyEvent->child (
348 pid => $pid, 362 pid => $pid,
349 cb => sub { 363 cb => sub {
350 my ($pid, $status) = @_; 364 my ($pid, $status) = @_;
351 warn "pid $pid exited with status $status"; 365 warn "pid $pid exited with status $status";
352 $done->send; 366 $done->send;
353 }, 367 },
354 ); 368 );
355 369
356 # do something else, then wait for process exit 370 # do something else, then wait for process exit
357 $done->recv; 371 $done->recv;
358 372
359=head2 CONDITION VARIABLES 373=head2 CONDITION VARIABLES
360 374
361If 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
362require you to run some blocking "loop", "run" or similar function that 376require you to run some blocking "loop", "run" or similar function that
583 597
584This is a mutator function that returns the callback set and optionally 598This is a mutator function that returns the callback set and optionally
585replaces it before doing so. 599replaces it before doing so.
586 600
587The 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
588C<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
589or 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.
590 605
591=back 606=back
592 607
593=head1 GLOBAL VARIABLES AND FUNCTIONS 608=head1 GLOBAL VARIABLES AND FUNCTIONS
594 609
792no warnings; 807no warnings;
793use strict; 808use strict;
794 809
795use Carp; 810use Carp;
796 811
797our $VERSION = '4.05'; 812our $VERSION = 4.11;
798our $MODEL; 813our $MODEL;
799 814
800our $AUTOLOAD; 815our $AUTOLOAD;
801our @ISA; 816our @ISA;
802 817
1158This functionality might change in future versions. 1173This functionality might change in future versions.
1159 1174
1160For 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
1161could start your program like this: 1176could start your program like this:
1162 1177
1163 PERL_ANYEVENT_MODEL=Perl perl ... 1178 PERL_ANYEVENT_MODEL=Perl perl ...
1164 1179
1165=item C<PERL_ANYEVENT_PROTOCOLS> 1180=item C<PERL_ANYEVENT_PROTOCOLS>
1166 1181
1167Used 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
1168for 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
1643specified in the variable. 1658specified in the variable.
1644 1659
1645You can make AnyEvent completely ignore this variable by deleting it 1660You can make AnyEvent completely ignore this variable by deleting it
1646before 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:
1647 1662
1648 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } 1663 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1649 1664
1650 use AnyEvent; 1665 use AnyEvent;
1651 1666
1652Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can 1667Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1653be 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
1654probably even less useful to an attacker than PERL_ANYEVENT_MODEL). 1669probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
1655 1670
1676Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 1691Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1677 1692
1678 1693
1679=head1 AUTHOR 1694=head1 AUTHOR
1680 1695
1681 Marc Lehmann <schmorp@schmorp.de> 1696 Marc Lehmann <schmorp@schmorp.de>
1682 http://home.schmorp.de/ 1697 http://home.schmorp.de/
1683 1698
1684=cut 1699=cut
1685 1700
16861 17011
1687 1702

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