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Revision 1.20 by root, Mon Dec 11 01:16:09 2006 UTC vs.
Revision 1.42 by root, Mon Apr 7 19:40:12 2008 UTC

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17 }); 17 });
18 18
19 my $w = AnyEvent->condvar; # stores wether a condition was flagged 19 my $w = AnyEvent->condvar; # stores wether a condition was flagged
20 $w->wait; # enters "main loop" till $condvar gets ->broadcast 20 $w->wait; # enters "main loop" till $condvar gets ->broadcast
21 $w->broadcast; # wake up current and all future wait's 21 $w->broadcast; # wake up current and all future wait's
22
23=head1 WHY YOU SHOULD USE THIS MODULE
24
25Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26nowadays. So what is different about AnyEvent?
27
28Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
29policy> and AnyEvent is I<small and efficient>.
30
31First and foremost, I<AnyEvent is not an event model> itself, it only
32interfaces to whatever event model the main program happens to use in a
33pragmatic way. For event models and certain classes of immortals alike,
34the statement "there can only be one" is a bitter reality, and AnyEvent
35helps hiding the differences.
36
37The goal of AnyEvent is to offer module authors the ability to do event
38programming (waiting for I/O or timer events) without subscribing to a
39religion, a way of living, and most importantly: without forcing your
40module users into the same thing by forcing them to use the same event
41model you use.
42
43For modules like POE or IO::Async (which is actually doing all I/O
44I<synchronously>...), using them in your module is like joining a
45cult: After you joined, you are dependent on them and you cannot use
46anything else, as it is simply incompatible to everything that isn't
47itself.
48
49AnyEvent + POE works fine. AnyEvent + Glib works fine. AnyEvent + Tk
50works fine etc. etc. but none of these work together with the rest: POE
51+ IO::Async? no go. Tk + Event? no go. If your module uses one of
52those, every user of your module has to use it, too. If your module
53uses AnyEvent, it works transparently with all event models it supports
54(including stuff like POE and IO::Async).
55
56In addition of being free of having to use I<the one and only true event
57model>, AnyEvent also is free of bloat and policy: with POE or similar
58modules, you get an enourmous amount of code and strict rules you have
59to follow. AnyEvent, on the other hand, is lean and to the point by only
60offering the functionality that is useful, in as thin as a wrapper as
61technically possible.
62
22 63
23=head1 DESCRIPTION 64=head1 DESCRIPTION
24 65
25L<AnyEvent> provides an identical interface to multiple event loops. This 66L<AnyEvent> provides an identical interface to multiple event loops. This
26allows module authors to utilise an event loop without forcing module 67allows module authors to utilise an event loop without forcing module
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70You can create I/O watcher by calling the C<< AnyEvent->io >> method with 111You can create I/O watcher by calling the C<< AnyEvent->io >> method with
71the following mandatory arguments: 112the following mandatory arguments:
72 113
73C<fh> the Perl I<filehandle> (not filedescriptor) to watch for 114C<fh> the Perl I<filehandle> (not filedescriptor) to watch for
74events. C<poll> must be a string that is either C<r> or C<w>, that creates 115events. C<poll> must be a string that is either C<r> or C<w>, that creates
75a watcher waiting for "r"eadable or "w"ritable events. C<cb> teh callback 116a watcher waiting for "r"eadable or "w"ritable events. C<cb> the callback
76to invoke everytime the filehandle becomes ready. 117to invoke everytime the filehandle becomes ready.
77 118
78Only one io watcher per C<fh> and C<poll> combination is allowed (i.e. on 119Only one io watcher per C<fh> and C<poll> combination is allowed (i.e. on
79a socket you can have one r + one w, not any more (limitation comes from 120a socket you can have one r + one w, not any more (limitation comes from
80Tk - if you are sure you are not using Tk this limitation is gone). 121Tk - if you are sure you are not using Tk this limitation is gone).
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109 my $w = AnyEvent->timer (after => 7.7, cb => sub { 150 my $w = AnyEvent->timer (after => 7.7, cb => sub {
110 warn "timeout\n"; 151 warn "timeout\n";
111 }); 152 });
112 153
113 # to cancel the timer: 154 # to cancel the timer:
114 undef $w 155 undef $w;
115 156
116=head2 CONDITION WATCHERS 157=head2 CONDITION WATCHERS
117 158
118Condition watchers can be created by calling the C<< AnyEvent->condvar >> 159Condition watchers can be created by calling the C<< AnyEvent->condvar >>
119method without any arguments. 160method without any arguments.
120 161
121A condition watcher watches for a condition - precisely that the C<< 162A condition watcher watches for a condition - precisely that the C<<
122->broadcast >> method has been called. 163->broadcast >> method has been called.
164
165Note that condition watchers recurse into the event loop - if you have
166two watchers that call C<< ->wait >> in a round-robbin fashion, you
167lose. Therefore, condition watchers are good to export to your caller, but
168you should avoid making a blocking wait, at least in callbacks, as this
169usually asks for trouble.
123 170
124The watcher has only two methods: 171The watcher has only two methods:
125 172
126=over 4 173=over 4
127 174
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161 208
162=head2 SIGNAL WATCHERS 209=head2 SIGNAL WATCHERS
163 210
164You can listen for signals using a signal watcher, C<signal> is the signal 211You can listen for signals using a signal watcher, C<signal> is the signal
165I<name> without any C<SIG> prefix. Multiple signals events can be clumped 212I<name> without any C<SIG> prefix. Multiple signals events can be clumped
166together into one callback invocation, and callbakc invocation might or 213together into one callback invocation, and callback invocation might or
167might not be asynchronous. 214might not be asynchronous.
168 215
169These watchers might use C<%SIG>, so programs overwriting those signals 216These watchers might use C<%SIG>, so programs overwriting those signals
170directly will likely not work correctly. 217directly will likely not work correctly.
171 218
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174 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); 221 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
175 222
176=head2 CHILD PROCESS WATCHERS 223=head2 CHILD PROCESS WATCHERS
177 224
178You can also listen for the status of a child process specified by the 225You can also listen for the status of a child process specified by the
179C<pid> argument. The watcher will only trigger once. This works by 226C<pid> argument (or any child if the pid argument is 0). The watcher will
180installing a signal handler for C<SIGCHLD>. 227trigger as often as status change for the child are received. This works
228by installing a signal handler for C<SIGCHLD>. The callback will be called with
229the pid and exit status (as returned by waitpid).
181 230
182Example: wait for pid 1333 231Example: wait for pid 1333
183 232
184 my $w = AnyEvent->child (pid => 1333, cb => sub { warn "exit status $?" }); 233 my $w = AnyEvent->child (pid => 1333, cb => sub { warn "exit status $?" });
185 234
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195C<AnyEvent::Impl:xxx> modules, but can be any other class in the case 244C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
196AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). 245AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
197 246
198The known classes so far are: 247The known classes so far are:
199 248
200 AnyEvent::Impl::Coro based on Coro::Event, best choise. 249 AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
250 AnyEvent::Impl::EV based on EV (an interface to libev, also best choice).
251 AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
201 AnyEvent::Impl::Event based on Event, also best choice :) 252 AnyEvent::Impl::Event based on Event, also second best choice :)
202 AnyEvent::Impl::Glib based on Glib, second-best choice. 253 AnyEvent::Impl::Glib based on Glib, second-best choice.
203 AnyEvent::Impl::Tk based on Tk, very bad choice. 254 AnyEvent::Impl::Tk based on Tk, very bad choice.
204 AnyEvent::Impl::Perl pure-perl implementation, inefficient. 255 AnyEvent::Impl::Perl pure-perl implementation, inefficient.
205 256
206=item AnyEvent::detect 257=item AnyEvent::detect
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245 296
246package AnyEvent; 297package AnyEvent;
247 298
248no warnings; 299no warnings;
249use strict; 300use strict;
301
250use Carp; 302use Carp;
251 303
252our $VERSION = '2.5'; 304our $VERSION = '3.0';
253our $MODEL; 305our $MODEL;
254 306
255our $AUTOLOAD; 307our $AUTOLOAD;
256our @ISA; 308our @ISA;
257 309
258our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 310our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
259 311
260our @REGISTRY; 312our @REGISTRY;
261 313
262my @models = ( 314my @models = (
315 [Coro::EV:: => AnyEvent::Impl::CoroEV::],
316 [EV:: => AnyEvent::Impl::EV::],
263 [Coro::Event:: => AnyEvent::Impl::Coro::], 317 [Coro::Event:: => AnyEvent::Impl::CoroEvent::],
264 [Event:: => AnyEvent::Impl::Event::], 318 [Event:: => AnyEvent::Impl::Event::],
265 [Glib:: => AnyEvent::Impl::Glib::], 319 [Glib:: => AnyEvent::Impl::Glib::],
266 [Tk:: => AnyEvent::Impl::Tk::], 320 [Tk:: => AnyEvent::Impl::Tk::],
267 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 321 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
268); 322);
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288 unless ($MODEL) { 342 unless ($MODEL) {
289 # try to load a model 343 # try to load a model
290 344
291 for (@REGISTRY, @models) { 345 for (@REGISTRY, @models) {
292 my ($package, $model) = @$_; 346 my ($package, $model) = @$_;
347 if (eval "require $package"
348 and ${"$package\::VERSION"} > 0
293 if (eval "require $model") { 349 and eval "require $model") {
294 $MODEL = $model; 350 $MODEL = $model;
295 warn "AnyEvent: autoprobed and loaded model '$model', using it.\n" if $verbose > 1; 351 warn "AnyEvent: autoprobed and loaded model '$model', using it.\n" if $verbose > 1;
296 last; 352 last;
297 } 353 }
298 } 354 }
299 355
300 $MODEL 356 $MODEL
301 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: Event (or Coro+Event), Glib or Tk."; 357 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event), Glib or Tk.";
302 } 358 }
303 359
304 unshift @ISA, $MODEL; 360 unshift @ISA, $MODEL;
305 push @{"$MODEL\::ISA"}, "AnyEvent::Base"; 361 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
306 } 362 }
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364 420
365# default implementation for ->child 421# default implementation for ->child
366 422
367our %PID_CB; 423our %PID_CB;
368our $CHLD_W; 424our $CHLD_W;
425our $CHLD_DELAY_W;
369our $PID_IDLE; 426our $PID_IDLE;
370our $WNOHANG; 427our $WNOHANG;
371 428
372sub _child_wait { 429sub _child_wait {
373 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 430 while (0 < (my $pid = waitpid -1, $WNOHANG)) {
374 $_->() for values %{ (delete $PID_CB{$pid}) || {} }; 431 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),
432 (values %{ $PID_CB{0} || {} });
375 } 433 }
376 434
377 undef $PID_IDLE; 435 undef $PID_IDLE;
436}
437
438sub _sigchld {
439 # make sure we deliver these changes "synchronous" with the event loop.
440 $CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
441 undef $CHLD_DELAY_W;
442 &_child_wait;
443 });
378} 444}
379 445
380sub child { 446sub child {
381 my (undef, %arg) = @_; 447 my (undef, %arg) = @_;
382 448
383 my $pid = uc $arg{pid} 449 defined (my $pid = $arg{pid} + 0)
384 or Carp::croak "required option 'pid' is missing"; 450 or Carp::croak "required option 'pid' is missing";
385 451
386 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 452 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
387 453
388 unless ($WNOHANG) { 454 unless ($WNOHANG) {
389 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_child_wait);
390 $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1; 455 $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1;
391 } 456 }
392 457
393 # child could be a zombie already 458 unless ($CHLD_W) {
394 $PID_IDLE ||= AnyEvent->timer (after => 0, cb => \&_child_wait); 459 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
460 # child could be a zombie already, so make at least one round
461 &_sigchld;
462 }
395 463
396 bless [$pid, $arg{cb}], "AnyEvent::Base::Child" 464 bless [$pid, $arg{cb}], "AnyEvent::Base::Child"
397} 465}
398 466
399sub AnyEvent::Base::Child::DESTROY { 467sub AnyEvent::Base::Child::DESTROY {
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435I<rxvt-unicode> distribution. 503I<rxvt-unicode> distribution.
436 504
437I<rxvt-unicode> also cheats a bit by not providing blocking access to 505I<rxvt-unicode> also cheats a bit by not providing blocking access to
438condition variables: code blocking while waiting for a condition will 506condition variables: code blocking while waiting for a condition will
439C<die>. This still works with most modules/usages, and blocking calls must 507C<die>. This still works with most modules/usages, and blocking calls must
440not be in an interactive appliation, so it makes sense. 508not be in an interactive application, so it makes sense.
441 509
442=head1 ENVIRONMENT VARIABLES 510=head1 ENVIRONMENT VARIABLES
443 511
444The following environment variables are used by this module: 512The following environment variables are used by this module:
445 513

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