ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/AnyEvent/lib/AnyEvent.pm
(Generate patch)

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.218 by root, Wed Jun 24 10:03:42 2009 UTC vs.
Revision 1.312 by root, Mon Feb 15 18:02:35 2010 UTC

1=head1 NAME 1=head1 NAME
2 2
3AnyEvent - provide framework for multiple event loops 3AnyEvent - the DBI of event loop programming
4 4
5EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported 5EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
6event loops. 6and POE are various supported event loops/environments.
7 7
8=head1 SYNOPSIS 8=head1 SYNOPSIS
9 9
10 use AnyEvent; 10 use AnyEvent;
11 11
40=head1 INTRODUCTION/TUTORIAL 40=head1 INTRODUCTION/TUTORIAL
41 41
42This manpage is mainly a reference manual. If you are interested 42This manpage is mainly a reference manual. If you are interested
43in a tutorial or some gentle introduction, have a look at the 43in a tutorial or some gentle introduction, have a look at the
44L<AnyEvent::Intro> manpage. 44L<AnyEvent::Intro> manpage.
45
46=head1 SUPPORT
47
48There is a mailinglist for discussing all things AnyEvent, and an IRC
49channel, too.
50
51See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
52Repository>, at L<http://anyevent.schmorp.de>, for more info.
45 53
46=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) 54=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47 55
48Glib, POE, IO::Async, Event... CPAN offers event models by the dozen 56Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49nowadays. So what is different about AnyEvent? 57nowadays. So what is different about AnyEvent?
173my variables are only visible after the statement in which they are 181my variables are only visible after the statement in which they are
174declared. 182declared.
175 183
176=head2 I/O WATCHERS 184=head2 I/O WATCHERS
177 185
186 $w = AnyEvent->io (
187 fh => <filehandle_or_fileno>,
188 poll => <"r" or "w">,
189 cb => <callback>,
190 );
191
178You can create an I/O watcher by calling the C<< AnyEvent->io >> method 192You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179with the following mandatory key-value pairs as arguments: 193with the following mandatory key-value pairs as arguments:
180 194
181C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch 195C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
182for events (AnyEvent might or might not keep a reference to this file 196for events (AnyEvent might or might not keep a reference to this file
183handle). Note that only file handles pointing to things for which 197handle). Note that only file handles pointing to things for which
184non-blocking operation makes sense are allowed. This includes sockets, 198non-blocking operation makes sense are allowed. This includes sockets,
185most character devices, pipes, fifos and so on, but not for example files 199most character devices, pipes, fifos and so on, but not for example files
186or block devices. 200or block devices.
211 undef $w; 225 undef $w;
212 }); 226 });
213 227
214=head2 TIME WATCHERS 228=head2 TIME WATCHERS
215 229
230 $w = AnyEvent->timer (after => <seconds>, cb => <callback>);
231
232 $w = AnyEvent->timer (
233 after => <fractional_seconds>,
234 interval => <fractional_seconds>,
235 cb => <callback>,
236 );
237
216You can create a time watcher by calling the C<< AnyEvent->timer >> 238You can create a time watcher by calling the C<< AnyEvent->timer >>
217method with the following mandatory arguments: 239method with the following mandatory arguments:
218 240
219C<after> specifies after how many seconds (fractional values are 241C<after> specifies after how many seconds (fractional values are
220supported) the callback should be invoked. C<cb> is the callback to invoke 242supported) the callback should be invoked. C<cb> is the callback to invoke
341might affect timers and time-outs. 363might affect timers and time-outs.
342 364
343When this is the case, you can call this method, which will update the 365When this is the case, you can call this method, which will update the
344event loop's idea of "current time". 366event loop's idea of "current time".
345 367
368A typical example would be a script in a web server (e.g. C<mod_perl>) -
369when mod_perl executes the script, then the event loop will have the wrong
370idea about the "current time" (being potentially far in the past, when the
371script ran the last time). In that case you should arrange a call to C<<
372AnyEvent->now_update >> each time the web server process wakes up again
373(e.g. at the start of your script, or in a handler).
374
346Note that updating the time I<might> cause some events to be handled. 375Note that updating the time I<might> cause some events to be handled.
347 376
348=back 377=back
349 378
350=head2 SIGNAL WATCHERS 379=head2 SIGNAL WATCHERS
380
381 $w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351 382
352You can watch for signals using a signal watcher, C<signal> is the signal 383You can watch for signals using a signal watcher, C<signal> is the signal
353I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl 384I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354callback to be invoked whenever a signal occurs. 385callback to be invoked whenever a signal occurs.
355 386
361invocation, and callback invocation will be synchronous. Synchronous means 392invocation, and callback invocation will be synchronous. Synchronous means
362that it might take a while until the signal gets handled by the process, 393that it might take a while until the signal gets handled by the process,
363but it is guaranteed not to interrupt any other callbacks. 394but it is guaranteed not to interrupt any other callbacks.
364 395
365The main advantage of using these watchers is that you can share a signal 396The main advantage of using these watchers is that you can share a signal
366between multiple watchers. 397between multiple watchers, and AnyEvent will ensure that signals will not
398interrupt your program at bad times.
367 399
368This watcher might use C<%SIG>, so programs overwriting those signals 400This watcher might use C<%SIG> (depending on the event loop used),
369directly will likely not work correctly. 401so programs overwriting those signals directly will likely not work
402correctly.
370 403
371Example: exit on SIGINT 404Example: exit on SIGINT
372 405
373 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); 406 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374 407
408=head3 Restart Behaviour
409
410While restart behaviour is up to the event loop implementation, most will
411not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
412pure perl implementation).
413
414=head3 Safe/Unsafe Signals
415
416Perl signals can be either "safe" (synchronous to opcode handling) or
417"unsafe" (asynchronous) - the former might get delayed indefinitely, the
418latter might corrupt your memory.
419
420AnyEvent signal handlers are, in addition, synchronous to the event loop,
421i.e. they will not interrupt your running perl program but will only be
422called as part of the normal event handling (just like timer, I/O etc.
423callbacks, too).
424
425=head3 Signal Races, Delays and Workarounds
426
427Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
428callbacks to signals in a generic way, which is a pity, as you cannot
429do race-free signal handling in perl, requiring C libraries for
430this. AnyEvent will try to do it's best, which means in some cases,
431signals will be delayed. The maximum time a signal might be delayed is
432specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
433variable can be changed only before the first signal watcher is created,
434and should be left alone otherwise. This variable determines how often
435AnyEvent polls for signals (in case a wake-up was missed). Higher values
436will cause fewer spurious wake-ups, which is better for power and CPU
437saving.
438
439All these problems can be avoided by installing the optional
440L<Async::Interrupt> module, which works with most event loops. It will not
441work with inherently broken event loops such as L<Event> or L<Event::Lib>
442(and not with L<POE> currently, as POE does it's own workaround with
443one-second latency). For those, you just have to suffer the delays.
444
375=head2 CHILD PROCESS WATCHERS 445=head2 CHILD PROCESS WATCHERS
376 446
447 $w = AnyEvent->child (pid => <process id>, cb => <callback>);
448
377You can also watch on a child process exit and catch its exit status. 449You can also watch on a child process exit and catch its exit status.
378 450
379The child process is specified by the C<pid> argument (if set to C<0>, it 451The child process is specified by the C<pid> argument (one some backends,
380watches for any child process exit). The watcher will triggered only when 452using C<0> watches for any child process exit, on others this will
381the child process has finished and an exit status is available, not on 453croak). The watcher will be triggered only when the child process has
382any trace events (stopped/continued). 454finished and an exit status is available, not on any trace events
455(stopped/continued).
383 456
384The callback will be called with the pid and exit status (as returned by 457The callback will be called with the pid and exit status (as returned by
385waitpid), so unlike other watcher types, you I<can> rely on child watcher 458waitpid), so unlike other watcher types, you I<can> rely on child watcher
386callback arguments. 459callback arguments.
387 460
392 465
393There is a slight catch to child watchers, however: you usually start them 466There is a slight catch to child watchers, however: you usually start them
394I<after> the child process was created, and this means the process could 467I<after> the child process was created, and this means the process could
395have exited already (and no SIGCHLD will be sent anymore). 468have exited already (and no SIGCHLD will be sent anymore).
396 469
397Not all event models handle this correctly (POE doesn't), but even for 470Not all event models handle this correctly (neither POE nor IO::Async do,
471see their AnyEvent::Impl manpages for details), but even for event models
398event models that I<do> handle this correctly, they usually need to be 472that I<do> handle this correctly, they usually need to be loaded before
399loaded before the process exits (i.e. before you fork in the first place). 473the process exits (i.e. before you fork in the first place). AnyEvent's
474pure perl event loop handles all cases correctly regardless of when you
475start the watcher.
400 476
401This means you cannot create a child watcher as the very first thing in an 477This means you cannot create a child watcher as the very first
402AnyEvent program, you I<have> to create at least one watcher before you 478thing in an AnyEvent program, you I<have> to create at least one
403C<fork> the child (alternatively, you can call C<AnyEvent::detect>). 479watcher before you C<fork> the child (alternatively, you can call
480C<AnyEvent::detect>).
481
482As most event loops do not support waiting for child events, they will be
483emulated by AnyEvent in most cases, in which the latency and race problems
484mentioned in the description of signal watchers apply.
404 485
405Example: fork a process and wait for it 486Example: fork a process and wait for it
406 487
407 my $done = AnyEvent->condvar; 488 my $done = AnyEvent->condvar;
408 489
420 # do something else, then wait for process exit 501 # do something else, then wait for process exit
421 $done->recv; 502 $done->recv;
422 503
423=head2 IDLE WATCHERS 504=head2 IDLE WATCHERS
424 505
425Sometimes there is a need to do something, but it is not so important 506 $w = AnyEvent->idle (cb => <callback>);
426to do it instantly, but only when there is nothing better to do. This
427"nothing better to do" is usually defined to be "no other events need
428attention by the event loop".
429 507
430Idle watchers ideally get invoked when the event loop has nothing 508Repeatedly invoke the callback after the process becomes idle, until
431better to do, just before it would block the process to wait for new 509either the watcher is destroyed or new events have been detected.
432events. Instead of blocking, the idle watcher is invoked.
433 510
434Most event loops unfortunately do not really support idle watchers (only 511Idle watchers are useful when there is a need to do something, but it
512is not so important (or wise) to do it instantly. The callback will be
513invoked only when there is "nothing better to do", which is usually
514defined as "all outstanding events have been handled and no new events
515have been detected". That means that idle watchers ideally get invoked
516when the event loop has just polled for new events but none have been
517detected. Instead of blocking to wait for more events, the idle watchers
518will be invoked.
519
520Unfortunately, most event loops do not really support idle watchers (only
435EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent 521EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
436will simply call the callback "from time to time". 522will simply call the callback "from time to time".
437 523
438Example: read lines from STDIN, but only process them when the 524Example: read lines from STDIN, but only process them when the
439program is otherwise idle: 525program is otherwise idle:
455 }); 541 });
456 }); 542 });
457 543
458=head2 CONDITION VARIABLES 544=head2 CONDITION VARIABLES
459 545
546 $cv = AnyEvent->condvar;
547
548 $cv->send (<list>);
549 my @res = $cv->recv;
550
460If you are familiar with some event loops you will know that all of them 551If you are familiar with some event loops you will know that all of them
461require you to run some blocking "loop", "run" or similar function that 552require you to run some blocking "loop", "run" or similar function that
462will actively watch for new events and call your callbacks. 553will actively watch for new events and call your callbacks.
463 554
464AnyEvent is different, it expects somebody else to run the event loop and 555AnyEvent is slightly different: it expects somebody else to run the event
465will only block when necessary (usually when told by the user). 556loop and will only block when necessary (usually when told by the user).
466 557
467The instrument to do that is called a "condition variable", so called 558The instrument to do that is called a "condition variable", so called
468because they represent a condition that must become true. 559because they represent a condition that must become true.
469 560
561Now is probably a good time to look at the examples further below.
562
470Condition variables can be created by calling the C<< AnyEvent->condvar 563Condition variables can be created by calling the C<< AnyEvent->condvar
471>> method, usually without arguments. The only argument pair allowed is 564>> method, usually without arguments. The only argument pair allowed is
472
473C<cb>, which specifies a callback to be called when the condition variable 565C<cb>, which specifies a callback to be called when the condition variable
474becomes true, with the condition variable as the first argument (but not 566becomes true, with the condition variable as the first argument (but not
475the results). 567the results).
476 568
477After creation, the condition variable is "false" until it becomes "true" 569After creation, the condition variable is "false" until it becomes "true"
482Condition variables are similar to callbacks, except that you can 574Condition variables are similar to callbacks, except that you can
483optionally wait for them. They can also be called merge points - points 575optionally wait for them. They can also be called merge points - points
484in time where multiple outstanding events have been processed. And yet 576in time where multiple outstanding events have been processed. And yet
485another way to call them is transactions - each condition variable can be 577another way to call them is transactions - each condition variable can be
486used to represent a transaction, which finishes at some point and delivers 578used to represent a transaction, which finishes at some point and delivers
487a result. 579a result. And yet some people know them as "futures" - a promise to
580compute/deliver something that you can wait for.
488 581
489Condition variables are very useful to signal that something has finished, 582Condition variables are very useful to signal that something has finished,
490for example, if you write a module that does asynchronous http requests, 583for example, if you write a module that does asynchronous http requests,
491then a condition variable would be the ideal candidate to signal the 584then a condition variable would be the ideal candidate to signal the
492availability of results. The user can either act when the callback is 585availability of results. The user can either act when the callback is
526 after => 1, 619 after => 1,
527 cb => sub { $result_ready->send }, 620 cb => sub { $result_ready->send },
528 ); 621 );
529 622
530 # this "blocks" (while handling events) till the callback 623 # this "blocks" (while handling events) till the callback
531 # calls send 624 # calls ->send
532 $result_ready->recv; 625 $result_ready->recv;
533 626
534Example: wait for a timer, but take advantage of the fact that 627Example: wait for a timer, but take advantage of the fact that condition
535condition variables are also code references. 628variables are also callable directly.
536 629
537 my $done = AnyEvent->condvar; 630 my $done = AnyEvent->condvar;
538 my $delay = AnyEvent->timer (after => 5, cb => $done); 631 my $delay = AnyEvent->timer (after => 5, cb => $done);
539 $done->recv; 632 $done->recv;
540 633
546 639
547 ... 640 ...
548 641
549 my @info = $couchdb->info->recv; 642 my @info = $couchdb->info->recv;
550 643
551And this is how you would just ste a callback to be called whenever the 644And this is how you would just set a callback to be called whenever the
552results are available: 645results are available:
553 646
554 $couchdb->info->cb (sub { 647 $couchdb->info->cb (sub {
555 my @info = $_[0]->recv; 648 my @info = $_[0]->recv;
556 }); 649 });
574immediately from within send. 667immediately from within send.
575 668
576Any arguments passed to the C<send> call will be returned by all 669Any arguments passed to the C<send> call will be returned by all
577future C<< ->recv >> calls. 670future C<< ->recv >> calls.
578 671
579Condition variables are overloaded so one can call them directly 672Condition variables are overloaded so one can call them directly (as if
580(as a code reference). Calling them directly is the same as calling 673they were a code reference). Calling them directly is the same as calling
581C<send>. Note, however, that many C-based event loops do not handle 674C<send>.
582overloading, so as tempting as it may be, passing a condition variable
583instead of a callback does not work. Both the pure perl and EV loops
584support overloading, however, as well as all functions that use perl to
585invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
586example).
587 675
588=item $cv->croak ($error) 676=item $cv->croak ($error)
589 677
590Similar to send, but causes all call's to C<< ->recv >> to invoke 678Similar to send, but causes all call's to C<< ->recv >> to invoke
591C<Carp::croak> with the given error message/object/scalar. 679C<Carp::croak> with the given error message/object/scalar.
592 680
593This can be used to signal any errors to the condition variable 681This can be used to signal any errors to the condition variable
594user/consumer. 682user/consumer. Doing it this way instead of calling C<croak> directly
683delays the error detetcion, but has the overwhelmign advantage that it
684diagnoses the error at the place where the result is expected, and not
685deep in some event clalback without connection to the actual code causing
686the problem.
595 687
596=item $cv->begin ([group callback]) 688=item $cv->begin ([group callback])
597 689
598=item $cv->end 690=item $cv->end
599
600These two methods are EXPERIMENTAL and MIGHT CHANGE.
601 691
602These two methods can be used to combine many transactions/events into 692These two methods can be used to combine many transactions/events into
603one. For example, a function that pings many hosts in parallel might want 693one. For example, a function that pings many hosts in parallel might want
604to use a condition variable for the whole process. 694to use a condition variable for the whole process.
605 695
606Every call to C<< ->begin >> will increment a counter, and every call to 696Every call to C<< ->begin >> will increment a counter, and every call to
607C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end 697C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
608>>, the (last) callback passed to C<begin> will be executed. That callback 698>>, the (last) callback passed to C<begin> will be executed, passing the
609is I<supposed> to call C<< ->send >>, but that is not required. If no 699condvar as first argument. That callback is I<supposed> to call C<< ->send
610callback was set, C<send> will be called without any arguments. 700>>, but that is not required. If no group callback was set, C<send> will
701be called without any arguments.
611 702
612Let's clarify this with the ping example: 703You can think of C<< $cv->send >> giving you an OR condition (one call
704sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
705condition (all C<begin> calls must be C<end>'ed before the condvar sends).
706
707Let's start with a simple example: you have two I/O watchers (for example,
708STDOUT and STDERR for a program), and you want to wait for both streams to
709close before activating a condvar:
613 710
614 my $cv = AnyEvent->condvar; 711 my $cv = AnyEvent->condvar;
615 712
713 $cv->begin; # first watcher
714 my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
715 defined sysread $fh1, my $buf, 4096
716 or $cv->end;
717 });
718
719 $cv->begin; # second watcher
720 my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
721 defined sysread $fh2, my $buf, 4096
722 or $cv->end;
723 });
724
725 $cv->recv;
726
727This works because for every event source (EOF on file handle), there is
728one call to C<begin>, so the condvar waits for all calls to C<end> before
729sending.
730
731The ping example mentioned above is slightly more complicated, as the
732there are results to be passwd back, and the number of tasks that are
733begung can potentially be zero:
734
735 my $cv = AnyEvent->condvar;
736
616 my %result; 737 my %result;
617 $cv->begin (sub { $cv->send (\%result) }); 738 $cv->begin (sub { shift->send (\%result) });
618 739
619 for my $host (@list_of_hosts) { 740 for my $host (@list_of_hosts) {
620 $cv->begin; 741 $cv->begin;
621 ping_host_then_call_callback $host, sub { 742 ping_host_then_call_callback $host, sub {
622 $result{$host} = ...; 743 $result{$host} = ...;
637loop, which serves two important purposes: first, it sets the callback 758loop, which serves two important purposes: first, it sets the callback
638to be called once the counter reaches C<0>, and second, it ensures that 759to be called once the counter reaches C<0>, and second, it ensures that
639C<send> is called even when C<no> hosts are being pinged (the loop 760C<send> is called even when C<no> hosts are being pinged (the loop
640doesn't execute once). 761doesn't execute once).
641 762
642This is the general pattern when you "fan out" into multiple subrequests: 763This is the general pattern when you "fan out" into multiple (but
643use an outer C<begin>/C<end> pair to set the callback and ensure C<end> 764potentially none) subrequests: use an outer C<begin>/C<end> pair to set
644is called at least once, and then, for each subrequest you start, call 765the callback and ensure C<end> is called at least once, and then, for each
645C<begin> and for each subrequest you finish, call C<end>. 766subrequest you start, call C<begin> and for each subrequest you finish,
767call C<end>.
646 768
647=back 769=back
648 770
649=head3 METHODS FOR CONSUMERS 771=head3 METHODS FOR CONSUMERS
650 772
666function will call C<croak>. 788function will call C<croak>.
667 789
668In list context, all parameters passed to C<send> will be returned, 790In list context, all parameters passed to C<send> will be returned,
669in scalar context only the first one will be returned. 791in scalar context only the first one will be returned.
670 792
793Note that doing a blocking wait in a callback is not supported by any
794event loop, that is, recursive invocation of a blocking C<< ->recv
795>> is not allowed, and the C<recv> call will C<croak> if such a
796condition is detected. This condition can be slightly loosened by using
797L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
798any thread that doesn't run the event loop itself.
799
671Not all event models support a blocking wait - some die in that case 800Not all event models support a blocking wait - some die in that case
672(programs might want to do that to stay interactive), so I<if you are 801(programs might want to do that to stay interactive), so I<if you are
673using this from a module, never require a blocking wait>, but let the 802using this from a module, never require a blocking wait>. Instead, let the
674caller decide whether the call will block or not (for example, by coupling 803caller decide whether the call will block or not (for example, by coupling
675condition variables with some kind of request results and supporting 804condition variables with some kind of request results and supporting
676callbacks so the caller knows that getting the result will not block, 805callbacks so the caller knows that getting the result will not block,
677while still supporting blocking waits if the caller so desires). 806while still supporting blocking waits if the caller so desires).
678 807
679Another reason I<never> to C<< ->recv >> in a module is that you cannot
680sensibly have two C<< ->recv >>'s in parallel, as that would require
681multiple interpreters or coroutines/threads, none of which C<AnyEvent>
682can supply.
683
684The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
685fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
686versions and also integrates coroutines into AnyEvent, making blocking
687C<< ->recv >> calls perfectly safe as long as they are done from another
688coroutine (one that doesn't run the event loop).
689
690You can ensure that C<< -recv >> never blocks by setting a callback and 808You can ensure that C<< -recv >> never blocks by setting a callback and
691only calling C<< ->recv >> from within that callback (or at a later 809only calling C<< ->recv >> from within that callback (or at a later
692time). This will work even when the event loop does not support blocking 810time). This will work even when the event loop does not support blocking
693waits otherwise. 811waits otherwise.
694 812
700=item $cb = $cv->cb ($cb->($cv)) 818=item $cb = $cv->cb ($cb->($cv))
701 819
702This is a mutator function that returns the callback set and optionally 820This is a mutator function that returns the callback set and optionally
703replaces it before doing so. 821replaces it before doing so.
704 822
705The callback will be called when the condition becomes "true", i.e. when 823The callback will be called when the condition becomes (or already was)
706C<send> or C<croak> are called, with the only argument being the condition 824"true", i.e. when C<send> or C<croak> are called (or were called), with
707variable itself. Calling C<recv> inside the callback or at any later time 825the only argument being the condition variable itself. Calling C<recv>
708is guaranteed not to block. 826inside the callback or at any later time is guaranteed not to block.
709 827
710=back 828=back
711 829
830=head1 SUPPORTED EVENT LOOPS/BACKENDS
831
832The available backend classes are (every class has its own manpage):
833
834=over 4
835
836=item Backends that are autoprobed when no other event loop can be found.
837
838EV is the preferred backend when no other event loop seems to be in
839use. If EV is not installed, then AnyEvent will fall back to its own
840pure-perl implementation, which is available everywhere as it comes with
841AnyEvent itself.
842
843 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
844 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
845
846=item Backends that are transparently being picked up when they are used.
847
848These will be used when they are currently loaded when the first watcher
849is created, in which case it is assumed that the application is using
850them. This means that AnyEvent will automatically pick the right backend
851when the main program loads an event module before anything starts to
852create watchers. Nothing special needs to be done by the main program.
853
854 AnyEvent::Impl::Event based on Event, very stable, few glitches.
855 AnyEvent::Impl::Glib based on Glib, slow but very stable.
856 AnyEvent::Impl::Tk based on Tk, very broken.
857 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
858 AnyEvent::Impl::POE based on POE, very slow, some limitations.
859 AnyEvent::Impl::Irssi used when running within irssi.
860
861=item Backends with special needs.
862
863Qt requires the Qt::Application to be instantiated first, but will
864otherwise be picked up automatically. As long as the main program
865instantiates the application before any AnyEvent watchers are created,
866everything should just work.
867
868 AnyEvent::Impl::Qt based on Qt.
869
870Support for IO::Async can only be partial, as it is too broken and
871architecturally limited to even support the AnyEvent API. It also
872is the only event loop that needs the loop to be set explicitly, so
873it can only be used by a main program knowing about AnyEvent. See
874L<AnyEvent::Impl::Async> for the gory details.
875
876 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
877
878=item Event loops that are indirectly supported via other backends.
879
880Some event loops can be supported via other modules:
881
882There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
883
884B<WxWidgets> has no support for watching file handles. However, you can
885use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
886polls 20 times per second, which was considered to be too horrible to even
887consider for AnyEvent.
888
889B<Prima> is not supported as nobody seems to be using it, but it has a POE
890backend, so it can be supported through POE.
891
892AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
893load L<POE> when detecting them, in the hope that POE will pick them up,
894in which case everything will be automatic.
895
896=back
897
712=head1 GLOBAL VARIABLES AND FUNCTIONS 898=head1 GLOBAL VARIABLES AND FUNCTIONS
713 899
900These are not normally required to use AnyEvent, but can be useful to
901write AnyEvent extension modules.
902
714=over 4 903=over 4
715 904
716=item $AnyEvent::MODEL 905=item $AnyEvent::MODEL
717 906
718Contains C<undef> until the first watcher is being created. Then it 907Contains C<undef> until the first watcher is being created, before the
908backend has been autodetected.
909
719contains the event model that is being used, which is the name of the 910Afterwards it contains the event model that is being used, which is the
720Perl class implementing the model. This class is usually one of the 911name of the Perl class implementing the model. This class is usually one
721C<AnyEvent::Impl:xxx> modules, but can be any other class in the case 912of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
722AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). 913case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
723 914will be C<urxvt::anyevent>).
724The known classes so far are:
725
726 AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
727 AnyEvent::Impl::Event based on Event, second best choice.
728 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
729 AnyEvent::Impl::Glib based on Glib, third-best choice.
730 AnyEvent::Impl::Tk based on Tk, very bad choice.
731 AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
732 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
733 AnyEvent::Impl::POE based on POE, not generic enough for full support.
734
735There is no support for WxWidgets, as WxWidgets has no support for
736watching file handles. However, you can use WxWidgets through the
737POE Adaptor, as POE has a Wx backend that simply polls 20 times per
738second, which was considered to be too horrible to even consider for
739AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
740it's adaptor.
741
742AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
743autodetecting them.
744 915
745=item AnyEvent::detect 916=item AnyEvent::detect
746 917
747Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 918Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
748if necessary. You should only call this function right before you would 919if necessary. You should only call this function right before you would
749have created an AnyEvent watcher anyway, that is, as late as possible at 920have created an AnyEvent watcher anyway, that is, as late as possible at
750runtime. 921runtime, and not e.g. while initialising of your module.
922
923If you need to do some initialisation before AnyEvent watchers are
924created, use C<post_detect>.
751 925
752=item $guard = AnyEvent::post_detect { BLOCK } 926=item $guard = AnyEvent::post_detect { BLOCK }
753 927
754Arranges for the code block to be executed as soon as the event model is 928Arranges for the code block to be executed as soon as the event model is
755autodetected (or immediately if this has already happened). 929autodetected (or immediately if this has already happened).
756 930
931The block will be executed I<after> the actual backend has been detected
932(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
933created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
934other initialisations - see the sources of L<AnyEvent::Strict> or
935L<AnyEvent::AIO> to see how this is used.
936
937The most common usage is to create some global watchers, without forcing
938event module detection too early, for example, L<AnyEvent::AIO> creates
939and installs the global L<IO::AIO> watcher in a C<post_detect> block to
940avoid autodetecting the event module at load time.
941
757If called in scalar or list context, then it creates and returns an object 942If called in scalar or list context, then it creates and returns an object
758that automatically removes the callback again when it is destroyed. See 943that automatically removes the callback again when it is destroyed (or
944C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
759L<Coro::BDB> for a case where this is useful. 945a case where this is useful.
946
947Example: Create a watcher for the IO::AIO module and store it in
948C<$WATCHER>. Only do so after the event loop is initialised, though.
949
950 our WATCHER;
951
952 my $guard = AnyEvent::post_detect {
953 $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
954 };
955
956 # the ||= is important in case post_detect immediately runs the block,
957 # as to not clobber the newly-created watcher. assigning both watcher and
958 # post_detect guard to the same variable has the advantage of users being
959 # able to just C<undef $WATCHER> if the watcher causes them grief.
960
961 $WATCHER ||= $guard;
760 962
761=item @AnyEvent::post_detect 963=item @AnyEvent::post_detect
762 964
763If there are any code references in this array (you can C<push> to it 965If there are any code references in this array (you can C<push> to it
764before or after loading AnyEvent), then they will called directly after 966before or after loading AnyEvent), then they will called directly after
765the event loop has been chosen. 967the event loop has been chosen.
766 968
767You should check C<$AnyEvent::MODEL> before adding to this array, though: 969You should check C<$AnyEvent::MODEL> before adding to this array, though:
768if it contains a true value then the event loop has already been detected, 970if it is defined then the event loop has already been detected, and the
769and the array will be ignored. 971array will be ignored.
770 972
771Best use C<AnyEvent::post_detect { BLOCK }> instead. 973Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
974it, as it takes care of these details.
975
976This variable is mainly useful for modules that can do something useful
977when AnyEvent is used and thus want to know when it is initialised, but do
978not need to even load it by default. This array provides the means to hook
979into AnyEvent passively, without loading it.
980
981Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
982together, you could put this into Coro (this is the actual code used by
983Coro to accomplish this):
984
985 if (defined $AnyEvent::MODEL) {
986 # AnyEvent already initialised, so load Coro::AnyEvent
987 require Coro::AnyEvent;
988 } else {
989 # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
990 # as soon as it is
991 push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
992 }
772 993
773=back 994=back
774 995
775=head1 WHAT TO DO IN A MODULE 996=head1 WHAT TO DO IN A MODULE
776 997
831 1052
832 1053
833=head1 OTHER MODULES 1054=head1 OTHER MODULES
834 1055
835The following is a non-exhaustive list of additional modules that use 1056The following is a non-exhaustive list of additional modules that use
836AnyEvent and can therefore be mixed easily with other AnyEvent modules 1057AnyEvent as a client and can therefore be mixed easily with other AnyEvent
837in the same program. Some of the modules come with AnyEvent, some are 1058modules and other event loops in the same program. Some of the modules
838available via CPAN. 1059come with AnyEvent, most are available via CPAN.
839 1060
840=over 4 1061=over 4
841 1062
842=item L<AnyEvent::Util> 1063=item L<AnyEvent::Util>
843 1064
852 1073
853=item L<AnyEvent::Handle> 1074=item L<AnyEvent::Handle>
854 1075
855Provide read and write buffers, manages watchers for reads and writes, 1076Provide read and write buffers, manages watchers for reads and writes,
856supports raw and formatted I/O, I/O queued and fully transparent and 1077supports raw and formatted I/O, I/O queued and fully transparent and
857non-blocking SSL/TLS. 1078non-blocking SSL/TLS (via L<AnyEvent::TLS>.
858 1079
859=item L<AnyEvent::DNS> 1080=item L<AnyEvent::DNS>
860 1081
861Provides rich asynchronous DNS resolver capabilities. 1082Provides rich asynchronous DNS resolver capabilities.
862 1083
890 1111
891=item L<AnyEvent::GPSD> 1112=item L<AnyEvent::GPSD>
892 1113
893A non-blocking interface to gpsd, a daemon delivering GPS information. 1114A non-blocking interface to gpsd, a daemon delivering GPS information.
894 1115
1116=item L<AnyEvent::IRC>
1117
1118AnyEvent based IRC client module family (replacing the older Net::IRC3).
1119
1120=item L<AnyEvent::XMPP>
1121
1122AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1123Net::XMPP2>.
1124
895=item L<AnyEvent::IGS> 1125=item L<AnyEvent::IGS>
896 1126
897A non-blocking interface to the Internet Go Server protocol (used by 1127A non-blocking interface to the Internet Go Server protocol (used by
898L<App::IGS>). 1128L<App::IGS>).
899 1129
900=item L<AnyEvent::IRC>
901
902AnyEvent based IRC client module family (replacing the older Net::IRC3).
903
904=item L<Net::XMPP2>
905
906AnyEvent based XMPP (Jabber protocol) module family.
907
908=item L<Net::FCP> 1130=item L<Net::FCP>
909 1131
910AnyEvent-based implementation of the Freenet Client Protocol, birthplace 1132AnyEvent-based implementation of the Freenet Client Protocol, birthplace
911of AnyEvent. 1133of AnyEvent.
912 1134
916 1138
917=item L<Coro> 1139=item L<Coro>
918 1140
919Has special support for AnyEvent via L<Coro::AnyEvent>. 1141Has special support for AnyEvent via L<Coro::AnyEvent>.
920 1142
921=item L<IO::Lambda>
922
923The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
924
925=back 1143=back
926 1144
927=cut 1145=cut
928 1146
929package AnyEvent; 1147package AnyEvent;
930 1148
931no warnings; 1149# basically a tuned-down version of common::sense
932use strict qw(vars subs); 1150sub common_sense {
1151 # from common:.sense 1.0
1152 ${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
1153 # use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1154 $^H |= 0x00000600;
1155}
933 1156
1157BEGIN { AnyEvent::common_sense }
1158
934use Carp; 1159use Carp ();
935 1160
936our $VERSION = 4.412; 1161our $VERSION = '5.24';
937our $MODEL; 1162our $MODEL;
938 1163
939our $AUTOLOAD; 1164our $AUTOLOAD;
940our @ISA; 1165our @ISA;
941 1166
942our @REGISTRY; 1167our @REGISTRY;
943 1168
944our $WIN32; 1169our $VERBOSE;
945 1170
946BEGIN { 1171BEGIN {
1172 eval "sub CYGWIN(){" . (($^O =~ /cygwin/i) *1) . "}";
947 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; 1173 eval "sub WIN32 (){" . (($^O =~ /mswin32/i)*1) . "}";
948 eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; 1174 eval "sub TAINT (){" . (${^TAINT} *1) . "}";
949 1175
950 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} 1176 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
951 if ${^TAINT}; 1177 if ${^TAINT};
952}
953 1178
954our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1179 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
1180
1181}
1182
1183our $MAX_SIGNAL_LATENCY = 10;
955 1184
956our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1185our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
957 1186
958{ 1187{
959 my $idx; 1188 my $idx;
961 for reverse split /\s*,\s*/, 1190 for reverse split /\s*,\s*/,
962 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; 1191 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
963} 1192}
964 1193
965my @models = ( 1194my @models = (
966 [EV:: => AnyEvent::Impl::EV::], 1195 [EV:: => AnyEvent::Impl::EV:: , 1],
967 [Event:: => AnyEvent::Impl::Event::],
968 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 1196 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
969 # everything below here will not be autoprobed 1197 # everything below here will not (normally) be autoprobed
970 # as the pureperl backend should work everywhere 1198 # as the pureperl backend should work everywhere
971 # and is usually faster 1199 # and is usually faster
1200 [Event:: => AnyEvent::Impl::Event::, 1],
1201 [Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1202 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1203 [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
972 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles 1204 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
973 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
974 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
975 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1205 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
976 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1206 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
977 [Wx:: => AnyEvent::Impl::POE::], 1207 [Wx:: => AnyEvent::Impl::POE::],
978 [Prima:: => AnyEvent::Impl::POE::], 1208 [Prima:: => AnyEvent::Impl::POE::],
1209 # IO::Async is just too broken - we would need workarounds for its
1210 # byzantine signal and broken child handling, among others.
1211 # IO::Async is rather hard to detect, as it doesn't have any
1212 # obvious default class.
1213 [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1214 [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1215 [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1216 [AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
979); 1217);
980 1218
981our %method = map +($_ => 1), 1219our %method = map +($_ => 1),
982 qw(io timer time now now_update signal child idle condvar one_event DESTROY); 1220 qw(io timer time now now_update signal child idle condvar one_event DESTROY);
983 1221
987 my ($cb) = @_; 1225 my ($cb) = @_;
988 1226
989 if ($MODEL) { 1227 if ($MODEL) {
990 $cb->(); 1228 $cb->();
991 1229
992 1 1230 undef
993 } else { 1231 } else {
994 push @post_detect, $cb; 1232 push @post_detect, $cb;
995 1233
996 defined wantarray 1234 defined wantarray
997 ? bless \$cb, "AnyEvent::Util::postdetect" 1235 ? bless \$cb, "AnyEvent::Util::postdetect"
1002sub AnyEvent::Util::postdetect::DESTROY { 1240sub AnyEvent::Util::postdetect::DESTROY {
1003 @post_detect = grep $_ != ${$_[0]}, @post_detect; 1241 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1004} 1242}
1005 1243
1006sub detect() { 1244sub detect() {
1245 # free some memory
1246 *detect = sub () { $MODEL };
1247
1248 local $!; # for good measure
1249 local $SIG{__DIE__};
1250
1251 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1252 my $model = "AnyEvent::Impl::$1";
1253 if (eval "require $model") {
1254 $MODEL = $model;
1255 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1256 } else {
1257 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1258 }
1259 }
1260
1261 # check for already loaded models
1007 unless ($MODEL) { 1262 unless ($MODEL) {
1008 no strict 'refs'; 1263 for (@REGISTRY, @models) {
1009 local $SIG{__DIE__}; 1264 my ($package, $model) = @$_;
1010 1265 if (${"$package\::VERSION"} > 0) {
1011 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1012 my $model = "AnyEvent::Impl::$1";
1013 if (eval "require $model") { 1266 if (eval "require $model") {
1014 $MODEL = $model; 1267 $MODEL = $model;
1015 warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1; 1268 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1016 } else { 1269 last;
1017 warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose; 1270 }
1018 } 1271 }
1019 } 1272 }
1020 1273
1021 # check for already loaded models
1022 unless ($MODEL) { 1274 unless ($MODEL) {
1275 # try to autoload a model
1023 for (@REGISTRY, @models) { 1276 for (@REGISTRY, @models) {
1024 my ($package, $model) = @$_; 1277 my ($package, $model, $autoload) = @$_;
1278 if (
1279 $autoload
1280 and eval "require $package"
1025 if (${"$package\::VERSION"} > 0) { 1281 and ${"$package\::VERSION"} > 0
1026 if (eval "require $model") { 1282 and eval "require $model"
1283 ) {
1027 $MODEL = $model; 1284 $MODEL = $model;
1028 warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1; 1285 warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1029 last; 1286 last;
1030 }
1031 } 1287 }
1032 } 1288 }
1033 1289
1034 unless ($MODEL) {
1035 # try to load a model
1036
1037 for (@REGISTRY, @models) {
1038 my ($package, $model) = @$_;
1039 if (eval "require $package"
1040 and ${"$package\::VERSION"} > 0
1041 and eval "require $model") {
1042 $MODEL = $model;
1043 warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1044 last;
1045 }
1046 }
1047
1048 $MODEL 1290 $MODEL
1049 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n"; 1291 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
1050 }
1051 } 1292 }
1052
1053 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1054
1055 unshift @ISA, $MODEL;
1056
1057 require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1058
1059 (shift @post_detect)->() while @post_detect;
1060 } 1293 }
1294
1295 @models = (); # free probe data
1296
1297 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1298 unshift @ISA, $MODEL;
1299
1300 require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1301
1302 (shift @post_detect)->() while @post_detect;
1061 1303
1062 $MODEL 1304 $MODEL
1063} 1305}
1064 1306
1065sub AUTOLOAD { 1307sub AUTOLOAD {
1066 (my $func = $AUTOLOAD) =~ s/.*://; 1308 (my $func = $AUTOLOAD) =~ s/.*://;
1067 1309
1068 $method{$func} 1310 $method{$func}
1069 or croak "$func: not a valid method for AnyEvent objects"; 1311 or Carp::croak "$func: not a valid AnyEvent class method";
1070 1312
1071 detect unless $MODEL; 1313 detect;
1072 1314
1073 my $class = shift; 1315 my $class = shift;
1074 $class->$func (@_); 1316 $class->$func (@_);
1075} 1317}
1076 1318
1077# utility function to dup a filehandle. this is used by many backends 1319# utility function to dup a filehandle. this is used by many backends
1078# to support binding more than one watcher per filehandle (they usually 1320# to support binding more than one watcher per filehandle (they usually
1079# allow only one watcher per fd, so we dup it to get a different one). 1321# allow only one watcher per fd, so we dup it to get a different one).
1080sub _dupfh($$$$) { 1322sub _dupfh($$;$$) {
1081 my ($poll, $fh, $r, $w) = @_; 1323 my ($poll, $fh, $r, $w) = @_;
1082 1324
1083 # cygwin requires the fh mode to be matching, unix doesn't 1325 # cygwin requires the fh mode to be matching, unix doesn't
1084 my ($rw, $mode) = $poll eq "r" ? ($r, "<") 1326 my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1085 : $poll eq "w" ? ($w, ">")
1086 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1087 1327
1088 open my $fh2, "$mode&" . fileno $fh 1328 open my $fh2, $mode, $fh
1089 or die "cannot dup() filehandle: $!,"; 1329 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1090 1330
1091 # we assume CLOEXEC is already set by perl in all important cases 1331 # we assume CLOEXEC is already set by perl in all important cases
1092 1332
1093 ($fh2, $rw) 1333 ($fh2, $rw)
1094} 1334}
1095 1335
1336=head1 SIMPLIFIED AE API
1337
1338Starting with version 5.0, AnyEvent officially supports a second, much
1339simpler, API that is designed to reduce the calling, typing and memory
1340overhead.
1341
1342See the L<AE> manpage for details.
1343
1344=cut
1345
1346package AE;
1347
1348our $VERSION = $AnyEvent::VERSION;
1349
1350sub io($$$) {
1351 AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1352}
1353
1354sub timer($$$) {
1355 AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1356}
1357
1358sub signal($$) {
1359 AnyEvent->signal (signal => $_[0], cb => $_[1])
1360}
1361
1362sub child($$) {
1363 AnyEvent->child (pid => $_[0], cb => $_[1])
1364}
1365
1366sub idle($) {
1367 AnyEvent->idle (cb => $_[0])
1368}
1369
1370sub cv(;&) {
1371 AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1372}
1373
1374sub now() {
1375 AnyEvent->now
1376}
1377
1378sub now_update() {
1379 AnyEvent->now_update
1380}
1381
1382sub time() {
1383 AnyEvent->time
1384}
1385
1096package AnyEvent::Base; 1386package AnyEvent::Base;
1097 1387
1098# default implementations for many methods 1388# default implementations for many methods
1099 1389
1100BEGIN { 1390sub _time() {
1391 eval q{ # poor man's autoloading
1392 # probe for availability of Time::HiRes
1101 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { 1393 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1394 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1102 *_time = \&Time::HiRes::time; 1395 *_time = \&Time::HiRes::time;
1103 # if (eval "use POSIX (); (POSIX::times())... 1396 # if (eval "use POSIX (); (POSIX::times())...
1104 } else { 1397 } else {
1398 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1105 *_time = sub { time }; # epic fail 1399 *_time = sub (){ time }; # epic fail
1400 }
1106 } 1401 };
1402 die if $@;
1403
1404 &_time
1107} 1405}
1108 1406
1109sub time { _time } 1407sub time { _time }
1110sub now { _time } 1408sub now { _time }
1111sub now_update { } 1409sub now_update { }
1116 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" 1414 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1117} 1415}
1118 1416
1119# default implementation for ->signal 1417# default implementation for ->signal
1120 1418
1419our $HAVE_ASYNC_INTERRUPT;
1420
1421sub _have_async_interrupt() {
1422 $HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
1423 && eval "use Async::Interrupt 1.02 (); 1")
1424 unless defined $HAVE_ASYNC_INTERRUPT;
1425
1426 $HAVE_ASYNC_INTERRUPT
1427}
1428
1121our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); 1429our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1430our (%SIG_ASY, %SIG_ASY_W);
1431our ($SIG_COUNT, $SIG_TW);
1122 1432
1123sub _signal_exec { 1433# install a dummy wakeup watcher to reduce signal catching latency
1124 sysread $SIGPIPE_R, my $dummy, 4; 1434# used by Impls
1435sub _sig_add() {
1436 unless ($SIG_COUNT++) {
1437 # try to align timer on a full-second boundary, if possible
1438 my $NOW = AE::now;
1125 1439
1126 while (%SIG_EV) { 1440 $SIG_TW = AE::timer
1127 for (keys %SIG_EV) { 1441 $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1128 delete $SIG_EV{$_}; 1442 $MAX_SIGNAL_LATENCY,
1129 $_->() for values %{ $SIG_CB{$_} || {} }; 1443 sub { } # just for the PERL_ASYNC_CHECK
1444 ;
1445 }
1446}
1447
1448sub _sig_del {
1449 undef $SIG_TW
1450 unless --$SIG_COUNT;
1451}
1452
1453our $_sig_name_init; $_sig_name_init = sub {
1454 eval q{ # poor man's autoloading
1455 undef $_sig_name_init;
1456
1457 if (_have_async_interrupt) {
1458 *sig2num = \&Async::Interrupt::sig2num;
1459 *sig2name = \&Async::Interrupt::sig2name;
1460 } else {
1461 require Config;
1462
1463 my %signame2num;
1464 @signame2num{ split ' ', $Config::Config{sig_name} }
1465 = split ' ', $Config::Config{sig_num};
1466
1467 my @signum2name;
1468 @signum2name[values %signame2num] = keys %signame2num;
1469
1470 *sig2num = sub($) {
1471 $_[0] > 0 ? shift : $signame2num{+shift}
1472 };
1473 *sig2name = sub ($) {
1474 $_[0] > 0 ? $signum2name[+shift] : shift
1475 };
1130 } 1476 }
1131 } 1477 };
1132} 1478 die if $@;
1479};
1480
1481sub sig2num ($) { &$_sig_name_init; &sig2num }
1482sub sig2name($) { &$_sig_name_init; &sig2name }
1133 1483
1134sub signal { 1484sub signal {
1135 my (undef, %arg) = @_; 1485 eval q{ # poor man's autoloading {}
1486 # probe for availability of Async::Interrupt
1487 if (_have_async_interrupt) {
1488 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1136 1489
1137 unless ($SIGPIPE_R) { 1490 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1138 require Fcntl; 1491 $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1139 1492
1140 if (AnyEvent::WIN32) {
1141 require AnyEvent::Util;
1142
1143 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1144 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1145 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1146 } else { 1493 } else {
1494 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1495
1496 require Fcntl;
1497
1498 if (AnyEvent::WIN32) {
1499 require AnyEvent::Util;
1500
1501 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1502 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1503 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1504 } else {
1147 pipe $SIGPIPE_R, $SIGPIPE_W; 1505 pipe $SIGPIPE_R, $SIGPIPE_W;
1148 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R; 1506 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1149 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case 1507 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1150 1508
1151 # not strictly required, as $^F is normally 2, but let's make sure... 1509 # not strictly required, as $^F is normally 2, but let's make sure...
1152 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC; 1510 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1153 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC; 1511 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1512 }
1513
1514 $SIGPIPE_R
1515 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1516
1517 $SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1154 } 1518 }
1155 1519
1156 $SIGPIPE_R 1520 *signal = sub {
1157 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; 1521 my (undef, %arg) = @_;
1158 1522
1159 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1160 }
1161
1162 my $signal = uc $arg{signal} 1523 my $signal = uc $arg{signal}
1163 or Carp::croak "required option 'signal' is missing"; 1524 or Carp::croak "required option 'signal' is missing";
1164 1525
1526 if ($HAVE_ASYNC_INTERRUPT) {
1527 # async::interrupt
1528
1529 $signal = sig2num $signal;
1165 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1530 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1531
1532 $SIG_ASY{$signal} ||= new Async::Interrupt
1533 cb => sub { undef $SIG_EV{$signal} },
1534 signal => $signal,
1535 pipe => [$SIGPIPE_R->filenos],
1536 pipe_autodrain => 0,
1537 ;
1538
1539 } else {
1540 # pure perl
1541
1542 # AE::Util has been loaded in signal
1543 $signal = sig2name $signal;
1544 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1545
1166 $SIG{$signal} ||= sub { 1546 $SIG{$signal} ||= sub {
1167 local $!; 1547 local $!;
1168 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; 1548 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1169 undef $SIG_EV{$signal}; 1549 undef $SIG_EV{$signal};
1550 };
1551
1552 # can't do signal processing without introducing races in pure perl,
1553 # so limit the signal latency.
1554 _sig_add;
1555 }
1556
1557 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1558 };
1559
1560 *AnyEvent::Base::signal::DESTROY = sub {
1561 my ($signal, $cb) = @{$_[0]};
1562
1563 _sig_del;
1564
1565 delete $SIG_CB{$signal}{$cb};
1566
1567 $HAVE_ASYNC_INTERRUPT
1568 ? delete $SIG_ASY{$signal}
1569 : # delete doesn't work with older perls - they then
1570 # print weird messages, or just unconditionally exit
1571 # instead of getting the default action.
1572 undef $SIG{$signal}
1573 unless keys %{ $SIG_CB{$signal} };
1574 };
1575
1576 *_signal_exec = sub {
1577 $HAVE_ASYNC_INTERRUPT
1578 ? $SIGPIPE_R->drain
1579 : sysread $SIGPIPE_R, (my $dummy), 9;
1580
1581 while (%SIG_EV) {
1582 for (keys %SIG_EV) {
1583 delete $SIG_EV{$_};
1584 $_->() for values %{ $SIG_CB{$_} || {} };
1585 }
1586 }
1587 };
1170 }; 1588 };
1589 die if $@;
1171 1590
1172 bless [$signal, $arg{cb}], "AnyEvent::Base::signal" 1591 &signal
1173}
1174
1175sub AnyEvent::Base::signal::DESTROY {
1176 my ($signal, $cb) = @{$_[0]};
1177
1178 delete $SIG_CB{$signal}{$cb};
1179
1180 # delete doesn't work with older perls - they then
1181 # print weird messages, or just unconditionally exit
1182 # instead of getting the default action.
1183 undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1184} 1592}
1185 1593
1186# default implementation for ->child 1594# default implementation for ->child
1187 1595
1188our %PID_CB; 1596our %PID_CB;
1189our $CHLD_W; 1597our $CHLD_W;
1190our $CHLD_DELAY_W; 1598our $CHLD_DELAY_W;
1191our $WNOHANG; 1599our $WNOHANG;
1192 1600
1193sub _sigchld { 1601# used by many Impl's
1194 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 1602sub _emit_childstatus($$) {
1603 my (undef, $rpid, $rstatus) = @_;
1604
1605 $_->($rpid, $rstatus)
1195 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), 1606 for values %{ $PID_CB{$rpid} || {} },
1196 (values %{ $PID_CB{0} || {} }); 1607 values %{ $PID_CB{0} || {} };
1197 }
1198} 1608}
1199 1609
1200sub child { 1610sub child {
1611 eval q{ # poor man's autoloading {}
1612 *_sigchld = sub {
1613 my $pid;
1614
1615 AnyEvent->_emit_childstatus ($pid, $?)
1616 while ($pid = waitpid -1, $WNOHANG) > 0;
1617 };
1618
1619 *child = sub {
1201 my (undef, %arg) = @_; 1620 my (undef, %arg) = @_;
1202 1621
1203 defined (my $pid = $arg{pid} + 0) 1622 defined (my $pid = $arg{pid} + 0)
1204 or Carp::croak "required option 'pid' is missing"; 1623 or Carp::croak "required option 'pid' is missing";
1205 1624
1206 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1625 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
1207 1626
1627 # WNOHANG is almost cetrainly 1 everywhere
1628 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1629 ? 1
1208 $WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; 1630 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1209 1631
1210 unless ($CHLD_W) { 1632 unless ($CHLD_W) {
1211 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1633 $CHLD_W = AE::signal CHLD => \&_sigchld;
1212 # child could be a zombie already, so make at least one round 1634 # child could be a zombie already, so make at least one round
1213 &_sigchld; 1635 &_sigchld;
1214 } 1636 }
1215 1637
1216 bless [$pid, $arg{cb}], "AnyEvent::Base::child" 1638 bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1217} 1639 };
1218 1640
1219sub AnyEvent::Base::child::DESTROY { 1641 *AnyEvent::Base::child::DESTROY = sub {
1220 my ($pid, $cb) = @{$_[0]}; 1642 my ($pid, $cb) = @{$_[0]};
1221 1643
1222 delete $PID_CB{$pid}{$cb}; 1644 delete $PID_CB{$pid}{$cb};
1223 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 1645 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1224 1646
1225 undef $CHLD_W unless keys %PID_CB; 1647 undef $CHLD_W unless keys %PID_CB;
1648 };
1649 };
1650 die if $@;
1651
1652 &child
1226} 1653}
1227 1654
1228# idle emulation is done by simply using a timer, regardless 1655# idle emulation is done by simply using a timer, regardless
1229# of whether the process is idle or not, and not letting 1656# of whether the process is idle or not, and not letting
1230# the callback use more than 50% of the time. 1657# the callback use more than 50% of the time.
1231sub idle { 1658sub idle {
1659 eval q{ # poor man's autoloading {}
1660 *idle = sub {
1232 my (undef, %arg) = @_; 1661 my (undef, %arg) = @_;
1233 1662
1234 my ($cb, $w, $rcb) = $arg{cb}; 1663 my ($cb, $w, $rcb) = $arg{cb};
1235 1664
1236 $rcb = sub { 1665 $rcb = sub {
1237 if ($cb) { 1666 if ($cb) {
1238 $w = _time; 1667 $w = _time;
1239 &$cb; 1668 &$cb;
1240 $w = _time - $w; 1669 $w = _time - $w;
1241 1670
1242 # never use more then 50% of the time for the idle watcher, 1671 # never use more then 50% of the time for the idle watcher,
1243 # within some limits 1672 # within some limits
1244 $w = 0.0001 if $w < 0.0001; 1673 $w = 0.0001 if $w < 0.0001;
1245 $w = 5 if $w > 5; 1674 $w = 5 if $w > 5;
1246 1675
1247 $w = AnyEvent->timer (after => $w, cb => $rcb); 1676 $w = AE::timer $w, 0, $rcb;
1248 } else { 1677 } else {
1249 # clean up... 1678 # clean up...
1250 undef $w; 1679 undef $w;
1251 undef $rcb; 1680 undef $rcb;
1681 }
1682 };
1683
1684 $w = AE::timer 0.05, 0, $rcb;
1685
1686 bless \\$cb, "AnyEvent::Base::idle"
1252 } 1687 };
1688
1689 *AnyEvent::Base::idle::DESTROY = sub {
1690 undef $${$_[0]};
1691 };
1253 }; 1692 };
1693 die if $@;
1254 1694
1255 $w = AnyEvent->timer (after => 0.05, cb => $rcb); 1695 &idle
1256
1257 bless \\$cb, "AnyEvent::Base::idle"
1258}
1259
1260sub AnyEvent::Base::idle::DESTROY {
1261 undef $${$_[0]};
1262} 1696}
1263 1697
1264package AnyEvent::CondVar; 1698package AnyEvent::CondVar;
1265 1699
1266our @ISA = AnyEvent::CondVar::Base::; 1700our @ISA = AnyEvent::CondVar::Base::;
1267 1701
1268package AnyEvent::CondVar::Base; 1702package AnyEvent::CondVar::Base;
1269 1703
1270use overload 1704#use overload
1271 '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1705# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1272 fallback => 1; 1706# fallback => 1;
1707
1708# save 300+ kilobytes by dirtily hardcoding overloading
1709${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
1710*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
1711*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
1712${'AnyEvent::CondVar::Base::()'} = 1; # fallback
1713
1714our $WAITING;
1273 1715
1274sub _send { 1716sub _send {
1275 # nop 1717 # nop
1276} 1718}
1277 1719
1290sub ready { 1732sub ready {
1291 $_[0]{_ae_sent} 1733 $_[0]{_ae_sent}
1292} 1734}
1293 1735
1294sub _wait { 1736sub _wait {
1737 $WAITING
1738 and !$_[0]{_ae_sent}
1739 and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1740
1741 local $WAITING = 1;
1295 AnyEvent->one_event while !$_[0]{_ae_sent}; 1742 AnyEvent->one_event while !$_[0]{_ae_sent};
1296} 1743}
1297 1744
1298sub recv { 1745sub recv {
1299 $_[0]->_wait; 1746 $_[0]->_wait;
1301 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; 1748 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1302 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] 1749 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1303} 1750}
1304 1751
1305sub cb { 1752sub cb {
1306 $_[0]{_ae_cb} = $_[1] if @_ > 1; 1753 my $cv = shift;
1754
1755 @_
1756 and $cv->{_ae_cb} = shift
1757 and $cv->{_ae_sent}
1758 and (delete $cv->{_ae_cb})->($cv);
1759
1307 $_[0]{_ae_cb} 1760 $cv->{_ae_cb}
1308} 1761}
1309 1762
1310sub begin { 1763sub begin {
1311 ++$_[0]{_ae_counter}; 1764 ++$_[0]{_ae_counter};
1312 $_[0]{_ae_end_cb} = $_[1] if @_ > 1; 1765 $_[0]{_ae_end_cb} = $_[1] if @_ > 1;
1361C<PERL_ANYEVENT_MODEL>. 1814C<PERL_ANYEVENT_MODEL>.
1362 1815
1363When set to C<2> or higher, cause AnyEvent to report to STDERR which event 1816When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1364model it chooses. 1817model it chooses.
1365 1818
1819When set to C<8> or higher, then AnyEvent will report extra information on
1820which optional modules it loads and how it implements certain features.
1821
1366=item C<PERL_ANYEVENT_STRICT> 1822=item C<PERL_ANYEVENT_STRICT>
1367 1823
1368AnyEvent does not do much argument checking by default, as thorough 1824AnyEvent does not do much argument checking by default, as thorough
1369argument checking is very costly. Setting this variable to a true value 1825argument checking is very costly. Setting this variable to a true value
1370will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly 1826will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1371check the arguments passed to most method calls. If it finds any problems, 1827check the arguments passed to most method calls. If it finds any problems,
1372it will croak. 1828it will croak.
1373 1829
1374In other words, enables "strict" mode. 1830In other words, enables "strict" mode.
1375 1831
1376Unlike C<use strict>, it is definitely recommended to keep it off in 1832Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1377production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while 1833>>, it is definitely recommended to keep it off in production. Keeping
1378developing programs can be very useful, however. 1834C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1835can be very useful, however.
1379 1836
1380=item C<PERL_ANYEVENT_MODEL> 1837=item C<PERL_ANYEVENT_MODEL>
1381 1838
1382This can be used to specify the event model to be used by AnyEvent, before 1839This can be used to specify the event model to be used by AnyEvent, before
1383auto detection and -probing kicks in. It must be a string consisting 1840auto detection and -probing kicks in. It must be a string consisting
1426 1883
1427=item C<PERL_ANYEVENT_MAX_FORKS> 1884=item C<PERL_ANYEVENT_MAX_FORKS>
1428 1885
1429The maximum number of child processes that C<AnyEvent::Util::fork_call> 1886The maximum number of child processes that C<AnyEvent::Util::fork_call>
1430will create in parallel. 1887will create in parallel.
1888
1889=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
1890
1891The default value for the C<max_outstanding> parameter for the default DNS
1892resolver - this is the maximum number of parallel DNS requests that are
1893sent to the DNS server.
1894
1895=item C<PERL_ANYEVENT_RESOLV_CONF>
1896
1897The file to use instead of F</etc/resolv.conf> (or OS-specific
1898configuration) in the default resolver. When set to the empty string, no
1899default config will be used.
1900
1901=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1902
1903When neither C<ca_file> nor C<ca_path> was specified during
1904L<AnyEvent::TLS> context creation, and either of these environment
1905variables exist, they will be used to specify CA certificate locations
1906instead of a system-dependent default.
1907
1908=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1909
1910When these are set to C<1>, then the respective modules are not
1911loaded. Mostly good for testing AnyEvent itself.
1431 1912
1432=back 1913=back
1433 1914
1434=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1915=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1435 1916
1493 warn "read: $input\n"; # output what has been read 1974 warn "read: $input\n"; # output what has been read
1494 $cv->send if $input =~ /^q/i; # quit program if /^q/i 1975 $cv->send if $input =~ /^q/i; # quit program if /^q/i
1495 }, 1976 },
1496 ); 1977 );
1497 1978
1498 my $time_watcher; # can only be used once
1499
1500 sub new_timer {
1501 $timer = AnyEvent->timer (after => 1, cb => sub { 1979 my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1502 warn "timeout\n"; # print 'timeout' about every second 1980 warn "timeout\n"; # print 'timeout' at most every second
1503 &new_timer; # and restart the time
1504 }); 1981 });
1505 }
1506
1507 new_timer; # create first timer
1508 1982
1509 $cv->recv; # wait until user enters /^q/i 1983 $cv->recv; # wait until user enters /^q/i
1510 1984
1511=head1 REAL-WORLD EXAMPLE 1985=head1 REAL-WORLD EXAMPLE
1512 1986
1643through AnyEvent. The benchmark creates a lot of timers (with a zero 2117through AnyEvent. The benchmark creates a lot of timers (with a zero
1644timeout) and I/O watchers (watching STDOUT, a pty, to become writable, 2118timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1645which it is), lets them fire exactly once and destroys them again. 2119which it is), lets them fire exactly once and destroys them again.
1646 2120
1647Source code for this benchmark is found as F<eg/bench> in the AnyEvent 2121Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1648distribution. 2122distribution. It uses the L<AE> interface, which makes a real difference
2123for the EV and Perl backends only.
1649 2124
1650=head3 Explanation of the columns 2125=head3 Explanation of the columns
1651 2126
1652I<watcher> is the number of event watchers created/destroyed. Since 2127I<watcher> is the number of event watchers created/destroyed. Since
1653different event models feature vastly different performances, each event 2128different event models feature vastly different performances, each event
1674watcher. 2149watcher.
1675 2150
1676=head3 Results 2151=head3 Results
1677 2152
1678 name watchers bytes create invoke destroy comment 2153 name watchers bytes create invoke destroy comment
1679 EV/EV 400000 224 0.47 0.35 0.27 EV native interface 2154 EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1680 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers 2155 EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1681 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal 2156 Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1682 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation 2157 Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1683 Event/Event 16000 517 32.20 31.80 0.81 Event native interface 2158 Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1684 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers 2159 Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
2160 IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
2161 IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1685 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour 2162 Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1686 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers 2163 Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1687 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event 2164 POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1688 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select 2165 POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1689 2166
1690=head3 Discussion 2167=head3 Discussion
1691 2168
1692The benchmark does I<not> measure scalability of the event loop very 2169The benchmark does I<not> measure scalability of the event loop very
1693well. For example, a select-based event loop (such as the pure perl one) 2170well. For example, a select-based event loop (such as the pure perl one)
1705benchmark machine, handling an event takes roughly 1600 CPU cycles with 2182benchmark machine, handling an event takes roughly 1600 CPU cycles with
1706EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU 2183EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1707cycles with POE. 2184cycles with POE.
1708 2185
1709C<EV> is the sole leader regarding speed and memory use, which are both 2186C<EV> is the sole leader regarding speed and memory use, which are both
1710maximal/minimal, respectively. Even when going through AnyEvent, it uses 2187maximal/minimal, respectively. When using the L<AE> API there is zero
2188overhead (when going through the AnyEvent API create is about 5-6 times
2189slower, with other times being equal, so still uses far less memory than
1711far less memory than any other event loop and is still faster than Event 2190any other event loop and is still faster than Event natively).
1712natively.
1713 2191
1714The pure perl implementation is hit in a few sweet spots (both the 2192The pure perl implementation is hit in a few sweet spots (both the
1715constant timeout and the use of a single fd hit optimisations in the perl 2193constant timeout and the use of a single fd hit optimisations in the perl
1716interpreter and the backend itself). Nevertheless this shows that it 2194interpreter and the backend itself). Nevertheless this shows that it
1717adds very little overhead in itself. Like any select-based backend its 2195adds very little overhead in itself. Like any select-based backend its
1718performance becomes really bad with lots of file descriptors (and few of 2196performance becomes really bad with lots of file descriptors (and few of
1719them active), of course, but this was not subject of this benchmark. 2197them active), of course, but this was not subject of this benchmark.
1720 2198
1721The C<Event> module has a relatively high setup and callback invocation 2199The C<Event> module has a relatively high setup and callback invocation
1722cost, but overall scores in on the third place. 2200cost, but overall scores in on the third place.
2201
2202C<IO::Async> performs admirably well, about on par with C<Event>, even
2203when using its pure perl backend.
1723 2204
1724C<Glib>'s memory usage is quite a bit higher, but it features a 2205C<Glib>'s memory usage is quite a bit higher, but it features a
1725faster callback invocation and overall ends up in the same class as 2206faster callback invocation and overall ends up in the same class as
1726C<Event>. However, Glib scales extremely badly, doubling the number of 2207C<Event>. However, Glib scales extremely badly, doubling the number of
1727watchers increases the processing time by more than a factor of four, 2208watchers increases the processing time by more than a factor of four,
1788In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 2269In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1789(1%) are active. This mirrors the activity of large servers with many 2270(1%) are active. This mirrors the activity of large servers with many
1790connections, most of which are idle at any one point in time. 2271connections, most of which are idle at any one point in time.
1791 2272
1792Source code for this benchmark is found as F<eg/bench2> in the AnyEvent 2273Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1793distribution. 2274distribution. It uses the L<AE> interface, which makes a real difference
2275for the EV and Perl backends only.
1794 2276
1795=head3 Explanation of the columns 2277=head3 Explanation of the columns
1796 2278
1797I<sockets> is the number of sockets, and twice the number of "servers" (as 2279I<sockets> is the number of sockets, and twice the number of "servers" (as
1798each server has a read and write socket end). 2280each server has a read and write socket end).
1805it to another server. This includes deleting the old timeout and creating 2287it to another server. This includes deleting the old timeout and creating
1806a new one that moves the timeout into the future. 2288a new one that moves the timeout into the future.
1807 2289
1808=head3 Results 2290=head3 Results
1809 2291
1810 name sockets create request 2292 name sockets create request
1811 EV 20000 69.01 11.16 2293 EV 20000 62.66 7.99
1812 Perl 20000 73.32 35.87 2294 Perl 20000 68.32 32.64
1813 Event 20000 212.62 257.32 2295 IOAsync 20000 174.06 101.15 epoll
1814 Glib 20000 651.16 1896.30 2296 IOAsync 20000 174.67 610.84 poll
2297 Event 20000 202.69 242.91
2298 Glib 20000 557.01 1689.52
1815 POE 20000 349.67 12317.24 uses POE::Loop::Event 2299 POE 20000 341.54 12086.32 uses POE::Loop::Event
1816 2300
1817=head3 Discussion 2301=head3 Discussion
1818 2302
1819This benchmark I<does> measure scalability and overall performance of the 2303This benchmark I<does> measure scalability and overall performance of the
1820particular event loop. 2304particular event loop.
1822EV is again fastest. Since it is using epoll on my system, the setup time 2306EV is again fastest. Since it is using epoll on my system, the setup time
1823is relatively high, though. 2307is relatively high, though.
1824 2308
1825Perl surprisingly comes second. It is much faster than the C-based event 2309Perl surprisingly comes second. It is much faster than the C-based event
1826loops Event and Glib. 2310loops Event and Glib.
2311
2312IO::Async performs very well when using its epoll backend, and still quite
2313good compared to Glib when using its pure perl backend.
1827 2314
1828Event suffers from high setup time as well (look at its code and you will 2315Event suffers from high setup time as well (look at its code and you will
1829understand why). Callback invocation also has a high overhead compared to 2316understand why). Callback invocation also has a high overhead compared to
1830the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event 2317the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1831uses select or poll in basically all documented configurations. 2318uses select or poll in basically all documented configurations.
1943As you can see, the AnyEvent + EV combination even beats the 2430As you can see, the AnyEvent + EV combination even beats the
1944hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl 2431hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
1945backend easily beats IO::Lambda and POE. 2432backend easily beats IO::Lambda and POE.
1946 2433
1947And even the 100% non-blocking version written using the high-level (and 2434And even the 100% non-blocking version written using the high-level (and
1948slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a 2435slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
1949large margin, even though it does all of DNS, tcp-connect and socket I/O 2436higher level ("unoptimised") abstractions by a large margin, even though
1950in a non-blocking way. 2437it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
1951 2438
1952The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and 2439The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
1953F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are 2440F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
1954part of the IO::lambda distribution and were used without any changes. 2441part of the IO::Lambda distribution and were used without any changes.
1955 2442
1956 2443
1957=head1 SIGNALS 2444=head1 SIGNALS
1958 2445
1959AnyEvent currently installs handlers for these signals: 2446AnyEvent currently installs handlers for these signals:
1963=item SIGCHLD 2450=item SIGCHLD
1964 2451
1965A handler for C<SIGCHLD> is installed by AnyEvent's child watcher 2452A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1966emulation for event loops that do not support them natively. Also, some 2453emulation for event loops that do not support them natively. Also, some
1967event loops install a similar handler. 2454event loops install a similar handler.
2455
2456Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2457AnyEvent will reset it to default, to avoid losing child exit statuses.
1968 2458
1969=item SIGPIPE 2459=item SIGPIPE
1970 2460
1971A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> 2461A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1972when AnyEvent gets loaded. 2462when AnyEvent gets loaded.
1984 2474
1985=back 2475=back
1986 2476
1987=cut 2477=cut
1988 2478
2479undef $SIG{CHLD}
2480 if $SIG{CHLD} eq 'IGNORE';
2481
1989$SIG{PIPE} = sub { } 2482$SIG{PIPE} = sub { }
1990 unless defined $SIG{PIPE}; 2483 unless defined $SIG{PIPE};
1991 2484
2485=head1 RECOMMENDED/OPTIONAL MODULES
2486
2487One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2488it's built-in modules) are required to use it.
2489
2490That does not mean that AnyEvent won't take advantage of some additional
2491modules if they are installed.
2492
2493This section explains which additional modules will be used, and how they
2494affect AnyEvent's operation.
2495
2496=over 4
2497
2498=item L<Async::Interrupt>
2499
2500This slightly arcane module is used to implement fast signal handling: To
2501my knowledge, there is no way to do completely race-free and quick
2502signal handling in pure perl. To ensure that signals still get
2503delivered, AnyEvent will start an interval timer to wake up perl (and
2504catch the signals) with some delay (default is 10 seconds, look for
2505C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2506
2507If this module is available, then it will be used to implement signal
2508catching, which means that signals will not be delayed, and the event loop
2509will not be interrupted regularly, which is more efficient (and good for
2510battery life on laptops).
2511
2512This affects not just the pure-perl event loop, but also other event loops
2513that have no signal handling on their own (e.g. Glib, Tk, Qt).
2514
2515Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
2516and either employ their own workarounds (POE) or use AnyEvent's workaround
2517(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
2518does nothing for those backends.
2519
2520=item L<EV>
2521
2522This module isn't really "optional", as it is simply one of the backend
2523event loops that AnyEvent can use. However, it is simply the best event
2524loop available in terms of features, speed and stability: It supports
2525the AnyEvent API optimally, implements all the watcher types in XS, does
2526automatic timer adjustments even when no monotonic clock is available,
2527can take avdantage of advanced kernel interfaces such as C<epoll> and
2528C<kqueue>, and is the fastest backend I<by far>. You can even embed
2529L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2530
2531=item L<Guard>
2532
2533The guard module, when used, will be used to implement
2534C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2535lot less memory), but otherwise doesn't affect guard operation much. It is
2536purely used for performance.
2537
2538=item L<JSON> and L<JSON::XS>
2539
2540One of these modules is required when you want to read or write JSON data
2541via L<AnyEvent::Handle>. It is also written in pure-perl, but can take
2542advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2543
2544In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2545installed.
2546
2547=item L<Net::SSLeay>
2548
2549Implementing TLS/SSL in Perl is certainly interesting, but not very
2550worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2551the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2552
2553=item L<Time::HiRes>
2554
2555This module is part of perl since release 5.008. It will be used when the
2556chosen event library does not come with a timing source on it's own. The
2557pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
2558try to use a monotonic clock for timing stability.
2559
2560=back
2561
1992 2562
1993=head1 FORK 2563=head1 FORK
1994 2564
1995Most event libraries are not fork-safe. The ones who are usually are 2565Most event libraries are not fork-safe. The ones who are usually are
1996because they rely on inefficient but fork-safe C<select> or C<poll> 2566because they rely on inefficient but fork-safe C<select> or C<poll> calls
1997calls. Only L<EV> is fully fork-aware. 2567- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
2568are usually badly thought-out hacks that are incompatible with fork in
2569one way or another. Only L<EV> is fully fork-aware and ensures that you
2570continue event-processing in both parent and child (or both, if you know
2571what you are doing).
2572
2573This means that, in general, you cannot fork and do event processing in
2574the child if the event library was initialised before the fork (which
2575usually happens when the first AnyEvent watcher is created, or the library
2576is loaded).
1998 2577
1999If you have to fork, you must either do so I<before> creating your first 2578If you have to fork, you must either do so I<before> creating your first
2000watcher OR you must not use AnyEvent at all in the child. 2579watcher OR you must not use AnyEvent at all in the child OR you must do
2580something completely out of the scope of AnyEvent.
2581
2582The problem of doing event processing in the parent I<and> the child
2583is much more complicated: even for backends that I<are> fork-aware or
2584fork-safe, their behaviour is not usually what you want: fork clones all
2585watchers, that means all timers, I/O watchers etc. are active in both
2586parent and child, which is almost never what you want. USing C<exec>
2587to start worker children from some kind of manage rprocess is usually
2588preferred, because it is much easier and cleaner, at the expense of having
2589to have another binary.
2001 2590
2002 2591
2003=head1 SECURITY CONSIDERATIONS 2592=head1 SECURITY CONSIDERATIONS
2004 2593
2005AnyEvent can be forced to load any event model via 2594AnyEvent can be forced to load any event model via
2043L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 2632L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2044 2633
2045Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 2634Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2046L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 2635L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2047L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 2636L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2048L<AnyEvent::Impl::POE>. 2637L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2049 2638
2050Non-blocking file handles, sockets, TCP clients and 2639Non-blocking file handles, sockets, TCP clients and
2051servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. 2640servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2052 2641
2053Asynchronous DNS: L<AnyEvent::DNS>. 2642Asynchronous DNS: L<AnyEvent::DNS>.
2054 2643
2055Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, 2644Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
2645L<Coro::Event>,
2056 2646
2057Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 2647Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
2648L<AnyEvent::HTTP>.
2058 2649
2059 2650
2060=head1 AUTHOR 2651=head1 AUTHOR
2061 2652
2062 Marc Lehmann <schmorp@schmorp.de> 2653 Marc Lehmann <schmorp@schmorp.de>

Diff Legend

Removed lines
+ Added lines
< Changed lines
> Changed lines