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Revision 1.206 by root, Mon Apr 20 14:34:18 2009 UTC

1=head1 => NAME 1=head1 NAME
2 2
3AnyEvent - provide framework for multiple event loops 3AnyEvent - provide framework for multiple event loops
4 4
5EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops 5EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops
6 6
7=head1 SYNOPSIS 7=head1 SYNOPSIS
8 8
9 use AnyEvent; 9 use AnyEvent;
10 10
11 my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { 11 my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { ... });
12 ...
13 });
14 12
15 my $w = AnyEvent->timer (after => $seconds, cb => sub { 13 my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
14 my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
15
16 print AnyEvent->now; # prints current event loop time
17 print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
18
19 my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
20
21 my $w = AnyEvent->child (pid => $pid, cb => sub {
22 my ($pid, $status) = @_;
16 ... 23 ...
17 }); 24 });
18 25
19 my $w = AnyEvent->condvar; # stores whether a condition was flagged 26 my $w = AnyEvent->condvar; # stores whether a condition was flagged
20 $w->send; # wake up current and all future recv's 27 $w->send; # wake up current and all future recv's
21 $w->recv; # enters "main loop" till $condvar gets ->send 28 $w->recv; # enters "main loop" till $condvar gets ->send
29 # use a condvar in callback mode:
30 $w->cb (sub { $_[0]->recv });
31
32=head1 INTRODUCTION/TUTORIAL
33
34This manpage is mainly a reference manual. If you are interested
35in a tutorial or some gentle introduction, have a look at the
36L<AnyEvent::Intro> manpage.
22 37
23=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) 38=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24 39
25Glib, POE, IO::Async, Event... CPAN offers event models by the dozen 40Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26nowadays. So what is different about AnyEvent? 41nowadays. So what is different about AnyEvent?
27 42
28Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of 43Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
29policy> and AnyEvent is I<small and efficient>. 44policy> and AnyEvent is I<small and efficient>.
30 45
31First and foremost, I<AnyEvent is not an event model> itself, it only 46First 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 47interfaces to whatever event model the main program happens to use, in a
33pragmatic way. For event models and certain classes of immortals alike, 48pragmatic way. For event models and certain classes of immortals alike,
34the statement "there can only be one" is a bitter reality: In general, 49the statement "there can only be one" is a bitter reality: In general,
35only one event loop can be active at the same time in a process. AnyEvent 50only one event loop can be active at the same time in a process. AnyEvent
36helps hiding the differences between those event loops. 51cannot change this, but it can hide the differences between those event
52loops.
37 53
38The goal of AnyEvent is to offer module authors the ability to do event 54The goal of AnyEvent is to offer module authors the ability to do event
39programming (waiting for I/O or timer events) without subscribing to a 55programming (waiting for I/O or timer events) without subscribing to a
40religion, a way of living, and most importantly: without forcing your 56religion, a way of living, and most importantly: without forcing your
41module users into the same thing by forcing them to use the same event 57module users into the same thing by forcing them to use the same event
42model you use. 58model you use.
43 59
44For modules like POE or IO::Async (which is a total misnomer as it is 60For modules like POE or IO::Async (which is a total misnomer as it is
45actually doing all I/O I<synchronously>...), using them in your module is 61actually doing all I/O I<synchronously>...), using them in your module is
46like joining a cult: After you joined, you are dependent on them and you 62like joining a cult: After you joined, you are dependent on them and you
47cannot use anything else, as it is simply incompatible to everything that 63cannot use anything else, as they are simply incompatible to everything
48isn't itself. What's worse, all the potential users of your module are 64that isn't them. What's worse, all the potential users of your
49I<also> forced to use the same event loop you use. 65module are I<also> forced to use the same event loop you use.
50 66
51AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works 67AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52fine. AnyEvent + Tk works fine etc. etc. but none of these work together 68fine. AnyEvent + Tk works fine etc. etc. but none of these work together
53with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if 69with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
54your module uses one of those, every user of your module has to use it, 70your module uses one of those, every user of your module has to use it,
55too. But if your module uses AnyEvent, it works transparently with all 71too. But if your module uses AnyEvent, it works transparently with all
56event models it supports (including stuff like POE and IO::Async, as long 72event models it supports (including stuff like IO::Async, as long as those
57as those use one of the supported event loops. It is trivial to add new 73use one of the supported event loops. It is trivial to add new event loops
58event loops to AnyEvent, too, so it is future-proof). 74to AnyEvent, too, so it is future-proof).
59 75
60In addition to being free of having to use I<the one and only true event 76In addition to being free of having to use I<the one and only true event
61model>, AnyEvent also is free of bloat and policy: with POE or similar 77model>, AnyEvent also is free of bloat and policy: with POE or similar
62modules, you get an enormous amount of code and strict rules you have to 78modules, you get an enormous amount of code and strict rules you have to
63follow. AnyEvent, on the other hand, is lean and up to the point, by only 79follow. AnyEvent, on the other hand, is lean and up to the point, by only
121These watchers are normal Perl objects with normal Perl lifetime. After 137These watchers are normal Perl objects with normal Perl lifetime. After
122creating a watcher it will immediately "watch" for events and invoke the 138creating a watcher it will immediately "watch" for events and invoke the
123callback when the event occurs (of course, only when the event model 139callback when the event occurs (of course, only when the event model
124is in control). 140is in control).
125 141
142Note that B<callbacks must not permanently change global variables>
143potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
144callbacks must not C<die> >>. The former is good programming practise in
145Perl and the latter stems from the fact that exception handling differs
146widely between event loops.
147
126To disable the watcher you have to destroy it (e.g. by setting the 148To disable the watcher you have to destroy it (e.g. by setting the
127variable you store it in to C<undef> or otherwise deleting all references 149variable you store it in to C<undef> or otherwise deleting all references
128to it). 150to it).
129 151
130All watchers are created by calling a method on the C<AnyEvent> class. 152All watchers are created by calling a method on the C<AnyEvent> class.
132Many watchers either are used with "recursion" (repeating timers for 154Many watchers either are used with "recursion" (repeating timers for
133example), or need to refer to their watcher object in other ways. 155example), or need to refer to their watcher object in other ways.
134 156
135An any way to achieve that is this pattern: 157An any way to achieve that is this pattern:
136 158
137 my $w; $w = AnyEvent->type (arg => value ..., cb => sub { 159 my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
138 # you can use $w here, for example to undef it 160 # you can use $w here, for example to undef it
139 undef $w; 161 undef $w;
140 }); 162 });
141 163
142Note that C<my $w; $w => combination. This is necessary because in Perl, 164Note that C<my $w; $w => combination. This is necessary because in Perl,
143my variables are only visible after the statement in which they are 165my variables are only visible after the statement in which they are
144declared. 166declared.
145 167
146=head2 I/O WATCHERS 168=head2 I/O WATCHERS
147 169
148You can create an I/O watcher by calling the C<< AnyEvent->io >> method 170You can create an I/O watcher by calling the C<< AnyEvent->io >> method
149with the following mandatory key-value pairs as arguments: 171with the following mandatory key-value pairs as arguments:
150 172
151C<fh> the Perl I<file handle> (I<not> file descriptor) to watch 173C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
174for events (AnyEvent might or might not keep a reference to this file
175handle). Note that only file handles pointing to things for which
176non-blocking operation makes sense are allowed. This includes sockets,
177most character devices, pipes, fifos and so on, but not for example files
178or block devices.
179
152for events. C<poll> must be a string that is either C<r> or C<w>, 180C<poll> must be a string that is either C<r> or C<w>, which creates a
153which creates a watcher waiting for "r"eadable or "w"ritable events, 181watcher waiting for "r"eadable or "w"ritable events, respectively.
182
154respectively. C<cb> is the callback to invoke each time the file handle 183C<cb> is the callback to invoke each time the file handle becomes ready.
155becomes ready.
156 184
157Although the callback might get passed parameters, their value and 185Although the callback might get passed parameters, their value and
158presence is undefined and you cannot rely on them. Portable AnyEvent 186presence is undefined and you cannot rely on them. Portable AnyEvent
159callbacks cannot use arguments passed to I/O watcher callbacks. 187callbacks cannot use arguments passed to I/O watcher callbacks.
160 188
164 192
165Some event loops issue spurious readyness notifications, so you should 193Some event loops issue spurious readyness notifications, so you should
166always use non-blocking calls when reading/writing from/to your file 194always use non-blocking calls when reading/writing from/to your file
167handles. 195handles.
168 196
169Example:
170
171 # wait for readability of STDIN, then read a line and disable the watcher 197Example: wait for readability of STDIN, then read a line and disable the
198watcher.
199
172 my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { 200 my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
173 chomp (my $input = <STDIN>); 201 chomp (my $input = <STDIN>);
174 warn "read: $input\n"; 202 warn "read: $input\n";
175 undef $w; 203 undef $w;
176 }); 204 });
186 214
187Although the callback might get passed parameters, their value and 215Although the callback might get passed parameters, their value and
188presence is undefined and you cannot rely on them. Portable AnyEvent 216presence is undefined and you cannot rely on them. Portable AnyEvent
189callbacks cannot use arguments passed to time watcher callbacks. 217callbacks cannot use arguments passed to time watcher callbacks.
190 218
191The timer callback will be invoked at most once: if you want a repeating 219The callback will normally be invoked once only. If you specify another
192timer you have to create a new watcher (this is a limitation by both Tk 220parameter, C<interval>, as a strictly positive number (> 0), then the
193and Glib). 221callback will be invoked regularly at that interval (in fractional
222seconds) after the first invocation. If C<interval> is specified with a
223false value, then it is treated as if it were missing.
194 224
195Example: 225The callback will be rescheduled before invoking the callback, but no
226attempt is done to avoid timer drift in most backends, so the interval is
227only approximate.
196 228
197 # fire an event after 7.7 seconds 229Example: fire an event after 7.7 seconds.
230
198 my $w = AnyEvent->timer (after => 7.7, cb => sub { 231 my $w = AnyEvent->timer (after => 7.7, cb => sub {
199 warn "timeout\n"; 232 warn "timeout\n";
200 }); 233 });
201 234
202 # to cancel the timer: 235 # to cancel the timer:
203 undef $w; 236 undef $w;
204 237
205Example 2:
206
207 # fire an event after 0.5 seconds, then roughly every second 238Example 2: fire an event after 0.5 seconds, then roughly every second.
208 my $w;
209 239
210 my $cb = sub {
211 # cancel the old timer while creating a new one
212 $w = AnyEvent->timer (after => 1, cb => $cb); 240 my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
241 warn "timeout\n";
213 }; 242 };
214
215 # start the "loop" by creating the first watcher
216 $w = AnyEvent->timer (after => 0.5, cb => $cb);
217 243
218=head3 TIMING ISSUES 244=head3 TIMING ISSUES
219 245
220There are two ways to handle timers: based on real time (relative, "fire 246There are two ways to handle timers: based on real time (relative, "fire
221in 10 seconds") and based on wallclock time (absolute, "fire at 12 247in 10 seconds") and based on wallclock time (absolute, "fire at 12
294In either case, if you care (and in most cases, you don't), then you 320In either case, if you care (and in most cases, you don't), then you
295can get whatever behaviour you want with any event loop, by taking the 321can get whatever behaviour you want with any event loop, by taking the
296difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into 322difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
297account. 323account.
298 324
325=item AnyEvent->now_update
326
327Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
328the current time for each loop iteration (see the discussion of L<<
329AnyEvent->now >>, above).
330
331When a callback runs for a long time (or when the process sleeps), then
332this "current" time will differ substantially from the real time, which
333might affect timers and time-outs.
334
335When this is the case, you can call this method, which will update the
336event loop's idea of "current time".
337
338Note that updating the time I<might> cause some events to be handled.
339
299=back 340=back
300 341
301=head2 SIGNAL WATCHERS 342=head2 SIGNAL WATCHERS
302 343
303You can watch for signals using a signal watcher, C<signal> is the signal 344You can watch for signals using a signal watcher, C<signal> is the signal
304I<name> without any C<SIG> prefix, C<cb> is the Perl callback to 345I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
305be invoked whenever a signal occurs. 346callback to be invoked whenever a signal occurs.
306 347
307Although the callback might get passed parameters, their value and 348Although the callback might get passed parameters, their value and
308presence is undefined and you cannot rely on them. Portable AnyEvent 349presence is undefined and you cannot rely on them. Portable AnyEvent
309callbacks cannot use arguments passed to signal watcher callbacks. 350callbacks cannot use arguments passed to signal watcher callbacks.
310 351
326=head2 CHILD PROCESS WATCHERS 367=head2 CHILD PROCESS WATCHERS
327 368
328You can also watch on a child process exit and catch its exit status. 369You can also watch on a child process exit and catch its exit status.
329 370
330The child process is specified by the C<pid> argument (if set to C<0>, it 371The child process is specified by the C<pid> argument (if set to C<0>, it
331watches for any child process exit). The watcher will trigger as often 372watches for any child process exit). The watcher will triggered only when
332as status change for the child are received. This works by installing a 373the child process has finished and an exit status is available, not on
333signal handler for C<SIGCHLD>. The callback will be called with the pid 374any trace events (stopped/continued).
334and exit status (as returned by waitpid), so unlike other watcher types, 375
335you I<can> rely on child watcher callback arguments. 376The callback will be called with the pid and exit status (as returned by
377waitpid), so unlike other watcher types, you I<can> rely on child watcher
378callback arguments.
379
380This watcher type works by installing a signal handler for C<SIGCHLD>,
381and since it cannot be shared, nothing else should use SIGCHLD or reap
382random child processes (waiting for specific child processes, e.g. inside
383C<system>, is just fine).
336 384
337There is a slight catch to child watchers, however: you usually start them 385There is a slight catch to child watchers, however: you usually start them
338I<after> the child process was created, and this means the process could 386I<after> the child process was created, and this means the process could
339have exited already (and no SIGCHLD will be sent anymore). 387have exited already (and no SIGCHLD will be sent anymore).
340 388
346AnyEvent program, you I<have> to create at least one watcher before you 394AnyEvent program, you I<have> to create at least one watcher before you
347C<fork> the child (alternatively, you can call C<AnyEvent::detect>). 395C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
348 396
349Example: fork a process and wait for it 397Example: fork a process and wait for it
350 398
351 my $done = AnyEvent->condvar; 399 my $done = AnyEvent->condvar;
352 400
353 my $pid = fork or exit 5; 401 my $pid = fork or exit 5;
354 402
355 my $w = AnyEvent->child ( 403 my $w = AnyEvent->child (
356 pid => $pid, 404 pid => $pid,
357 cb => sub { 405 cb => sub {
358 my ($pid, $status) = @_; 406 my ($pid, $status) = @_;
359 warn "pid $pid exited with status $status"; 407 warn "pid $pid exited with status $status";
360 $done->send; 408 $done->send;
361 }, 409 },
362 ); 410 );
363 411
364 # do something else, then wait for process exit 412 # do something else, then wait for process exit
365 $done->recv; 413 $done->recv;
366 414
367=head2 CONDITION VARIABLES 415=head2 CONDITION VARIABLES
368 416
369If you are familiar with some event loops you will know that all of them 417If you are familiar with some event loops you will know that all of them
370require you to run some blocking "loop", "run" or similar function that 418require you to run some blocking "loop", "run" or similar function that
376The instrument to do that is called a "condition variable", so called 424The instrument to do that is called a "condition variable", so called
377because they represent a condition that must become true. 425because they represent a condition that must become true.
378 426
379Condition variables can be created by calling the C<< AnyEvent->condvar 427Condition variables can be created by calling the C<< AnyEvent->condvar
380>> method, usually without arguments. The only argument pair allowed is 428>> method, usually without arguments. The only argument pair allowed is
429
381C<cb>, which specifies a callback to be called when the condition variable 430C<cb>, which specifies a callback to be called when the condition variable
382becomes true. 431becomes true, with the condition variable as the first argument (but not
432the results).
383 433
384After creation, the condition variable is "false" until it becomes "true" 434After creation, the condition variable is "false" until it becomes "true"
385by calling the C<send> method (or calling the condition variable as if it 435by calling the C<send> method (or calling the condition variable as if it
386were a callback, read about the caveats in the description for the C<< 436were a callback, read about the caveats in the description for the C<<
387->send >> method). 437->send >> method).
443 493
444 my $done = AnyEvent->condvar; 494 my $done = AnyEvent->condvar;
445 my $delay = AnyEvent->timer (after => 5, cb => $done); 495 my $delay = AnyEvent->timer (after => 5, cb => $done);
446 $done->recv; 496 $done->recv;
447 497
498Example: Imagine an API that returns a condvar and doesn't support
499callbacks. This is how you make a synchronous call, for example from
500the main program:
501
502 use AnyEvent::CouchDB;
503
504 ...
505
506 my @info = $couchdb->info->recv;
507
508And this is how you would just ste a callback to be called whenever the
509results are available:
510
511 $couchdb->info->cb (sub {
512 my @info = $_[0]->recv;
513 });
514
448=head3 METHODS FOR PRODUCERS 515=head3 METHODS FOR PRODUCERS
449 516
450These methods should only be used by the producing side, i.e. the 517These methods should only be used by the producing side, i.e. the
451code/module that eventually sends the signal. Note that it is also 518code/module that eventually sends the signal. Note that it is also
452the producer side which creates the condvar in most cases, but it isn't 519the producer side which creates the condvar in most cases, but it isn't
585=item $bool = $cv->ready 652=item $bool = $cv->ready
586 653
587Returns true when the condition is "true", i.e. whether C<send> or 654Returns true when the condition is "true", i.e. whether C<send> or
588C<croak> have been called. 655C<croak> have been called.
589 656
590=item $cb = $cv->cb ([new callback]) 657=item $cb = $cv->cb ($cb->($cv))
591 658
592This is a mutator function that returns the callback set and optionally 659This is a mutator function that returns the callback set and optionally
593replaces it before doing so. 660replaces it before doing so.
594 661
595The callback will be called when the condition becomes "true", i.e. when 662The callback will be called when the condition becomes "true", i.e. when
596C<send> or C<croak> are called. Calling C<recv> inside the callback 663C<send> or C<croak> are called, with the only argument being the condition
597or at any later time is guaranteed not to block. 664variable itself. Calling C<recv> inside the callback or at any later time
665is guaranteed not to block.
598 666
599=back 667=back
600 668
601=head1 GLOBAL VARIABLES AND FUNCTIONS 669=head1 GLOBAL VARIABLES AND FUNCTIONS
602 670
731=item L<AnyEvent::Util> 799=item L<AnyEvent::Util>
732 800
733Contains various utility functions that replace often-used but blocking 801Contains various utility functions that replace often-used but blocking
734functions such as C<inet_aton> by event-/callback-based versions. 802functions such as C<inet_aton> by event-/callback-based versions.
735 803
736=item L<AnyEvent::Handle>
737
738Provide read and write buffers and manages watchers for reads and writes.
739
740=item L<AnyEvent::Socket> 804=item L<AnyEvent::Socket>
741 805
742Provides various utility functions for (internet protocol) sockets, 806Provides various utility functions for (internet protocol) sockets,
743addresses and name resolution. Also functions to create non-blocking tcp 807addresses and name resolution. Also functions to create non-blocking tcp
744connections or tcp servers, with IPv6 and SRV record support and more. 808connections or tcp servers, with IPv6 and SRV record support and more.
745 809
810=item L<AnyEvent::Handle>
811
812Provide read and write buffers, manages watchers for reads and writes,
813supports raw and formatted I/O, I/O queued and fully transparent and
814non-blocking SSL/TLS.
815
746=item L<AnyEvent::DNS> 816=item L<AnyEvent::DNS>
747 817
748Provides rich asynchronous DNS resolver capabilities. 818Provides rich asynchronous DNS resolver capabilities.
749 819
820=item L<AnyEvent::HTTP>
821
822A simple-to-use HTTP library that is capable of making a lot of concurrent
823HTTP requests.
824
750=item L<AnyEvent::HTTPD> 825=item L<AnyEvent::HTTPD>
751 826
752Provides a simple web application server framework. 827Provides a simple web application server framework.
753 828
754=item L<AnyEvent::FastPing> 829=item L<AnyEvent::FastPing>
755 830
756The fastest ping in the west. 831The fastest ping in the west.
757 832
833=item L<AnyEvent::DBI>
834
835Executes L<DBI> requests asynchronously in a proxy process.
836
837=item L<AnyEvent::AIO>
838
839Truly asynchronous I/O, should be in the toolbox of every event
840programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
841together.
842
843=item L<AnyEvent::BDB>
844
845Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
846L<BDB> and AnyEvent together.
847
848=item L<AnyEvent::GPSD>
849
850A non-blocking interface to gpsd, a daemon delivering GPS information.
851
852=item L<AnyEvent::IGS>
853
854A non-blocking interface to the Internet Go Server protocol (used by
855L<App::IGS>).
856
758=item L<Net::IRC3> 857=item L<AnyEvent::IRC>
759 858
760AnyEvent based IRC client module family. 859AnyEvent based IRC client module family (replacing the older Net::IRC3).
761 860
762=item L<Net::XMPP2> 861=item L<Net::XMPP2>
763 862
764AnyEvent based XMPP (Jabber protocol) module family. 863AnyEvent based XMPP (Jabber protocol) module family.
765 864
774 873
775=item L<Coro> 874=item L<Coro>
776 875
777Has special support for AnyEvent via L<Coro::AnyEvent>. 876Has special support for AnyEvent via L<Coro::AnyEvent>.
778 877
779=item L<AnyEvent::AIO>, L<IO::AIO>
780
781Truly asynchronous I/O, should be in the toolbox of every event
782programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
783together.
784
785=item L<AnyEvent::BDB>, L<BDB>
786
787Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
788IO::AIO and AnyEvent together.
789
790=item L<IO::Lambda> 878=item L<IO::Lambda>
791 879
792The lambda approach to I/O - don't ask, look there. Can use AnyEvent. 880The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
793 881
794=back 882=back
796=cut 884=cut
797 885
798package AnyEvent; 886package AnyEvent;
799 887
800no warnings; 888no warnings;
801use strict; 889use strict qw(vars subs);
802 890
803use Carp; 891use Carp;
804 892
805our $VERSION = '4.05'; 893our $VERSION = 4.352;
806our $MODEL; 894our $MODEL;
807 895
808our $AUTOLOAD; 896our $AUTOLOAD;
809our @ISA; 897our @ISA;
810 898
842 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 930 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
843 [Wx:: => AnyEvent::Impl::POE::], 931 [Wx:: => AnyEvent::Impl::POE::],
844 [Prima:: => AnyEvent::Impl::POE::], 932 [Prima:: => AnyEvent::Impl::POE::],
845); 933);
846 934
847our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY); 935our %method = map +($_ => 1),
936 qw(io timer time now now_update signal child condvar one_event DESTROY);
848 937
849our @post_detect; 938our @post_detect;
850 939
851sub post_detect(&) { 940sub post_detect(&) {
852 my ($cb) = @_; 941 my ($cb) = @_;
909 last; 998 last;
910 } 999 }
911 } 1000 }
912 1001
913 $MODEL 1002 $MODEL
914 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib."; 1003 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
915 } 1004 }
916 } 1005 }
917 1006
1007 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1008
918 unshift @ISA, $MODEL; 1009 unshift @ISA, $MODEL;
919 push @{"$MODEL\::ISA"}, "AnyEvent::Base"; 1010
1011 require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
920 1012
921 (shift @post_detect)->() while @post_detect; 1013 (shift @post_detect)->() while @post_detect;
922 } 1014 }
923 1015
924 $MODEL 1016 $MODEL
934 1026
935 my $class = shift; 1027 my $class = shift;
936 $class->$func (@_); 1028 $class->$func (@_);
937} 1029}
938 1030
1031# utility function to dup a filehandle. this is used by many backends
1032# to support binding more than one watcher per filehandle (they usually
1033# allow only one watcher per fd, so we dup it to get a different one).
1034sub _dupfh($$$$) {
1035 my ($poll, $fh, $r, $w) = @_;
1036
1037 # cygwin requires the fh mode to be matching, unix doesn't
1038 my ($rw, $mode) = $poll eq "r" ? ($r, "<")
1039 : $poll eq "w" ? ($w, ">")
1040 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1041
1042 open my $fh2, "$mode&" . fileno $fh
1043 or die "cannot dup() filehandle: $!,";
1044
1045 # we assume CLOEXEC is already set by perl in all important cases
1046
1047 ($fh2, $rw)
1048}
1049
939package AnyEvent::Base; 1050package AnyEvent::Base;
940 1051
941# default implementation for now and time 1052# default implementations for many methods
942 1053
943use Time::HiRes (); 1054BEGIN {
1055 if (eval "use Time::HiRes (); time (); 1") {
1056 *_time = \&Time::HiRes::time;
1057 # if (eval "use POSIX (); (POSIX::times())...
1058 } else {
1059 *_time = sub { time }; # epic fail
1060 }
1061}
944 1062
945sub time { Time::HiRes::time } 1063sub time { _time }
946sub now { Time::HiRes::time } 1064sub now { _time }
1065sub now_update { }
947 1066
948# default implementation for ->condvar 1067# default implementation for ->condvar
949 1068
950sub condvar { 1069sub condvar {
951 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: 1070 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
952} 1071}
953 1072
954# default implementation for ->signal 1073# default implementation for ->signal
955 1074
956our %SIG_CB; 1075our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1076
1077sub _signal_exec {
1078 sysread $SIGPIPE_R, my $dummy, 4;
1079
1080 while (%SIG_EV) {
1081 for (keys %SIG_EV) {
1082 delete $SIG_EV{$_};
1083 $_->() for values %{ $SIG_CB{$_} || {} };
1084 }
1085 }
1086}
957 1087
958sub signal { 1088sub signal {
959 my (undef, %arg) = @_; 1089 my (undef, %arg) = @_;
960 1090
1091 unless ($SIGPIPE_R) {
1092 require Fcntl;
1093
1094 if (AnyEvent::WIN32) {
1095 require AnyEvent::Util;
1096
1097 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1098 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1099 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1100 } else {
1101 pipe $SIGPIPE_R, $SIGPIPE_W;
1102 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1103 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1104 }
1105
1106 $SIGPIPE_R
1107 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1108
1109 # not strictly required, as $^F is normally 2, but let's make sure...
1110 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1111 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1112
1113 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1114 }
1115
961 my $signal = uc $arg{signal} 1116 my $signal = uc $arg{signal}
962 or Carp::croak "required option 'signal' is missing"; 1117 or Carp::croak "required option 'signal' is missing";
963 1118
964 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1119 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
965 $SIG{$signal} ||= sub { 1120 $SIG{$signal} ||= sub {
966 $_->() for values %{ $SIG_CB{$signal} || {} }; 1121 local $!;
1122 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1123 undef $SIG_EV{$signal};
967 }; 1124 };
968 1125
969 bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" 1126 bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
970} 1127}
971 1128
972sub AnyEvent::Base::Signal::DESTROY { 1129sub AnyEvent::Base::Signal::DESTROY {
973 my ($signal, $cb) = @{$_[0]}; 1130 my ($signal, $cb) = @{$_[0]};
974 1131
975 delete $SIG_CB{$signal}{$cb}; 1132 delete $SIG_CB{$signal}{$cb};
976 1133
977 $SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} }; 1134 delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
978} 1135}
979 1136
980# default implementation for ->child 1137# default implementation for ->child
981 1138
982our %PID_CB; 1139our %PID_CB;
1090 1247
1091# undocumented/compatibility with pre-3.4 1248# undocumented/compatibility with pre-3.4
1092*broadcast = \&send; 1249*broadcast = \&send;
1093*wait = \&_wait; 1250*wait = \&_wait;
1094 1251
1252=head1 ERROR AND EXCEPTION HANDLING
1253
1254In general, AnyEvent does not do any error handling - it relies on the
1255caller to do that if required. The L<AnyEvent::Strict> module (see also
1256the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
1257checking of all AnyEvent methods, however, which is highly useful during
1258development.
1259
1260As for exception handling (i.e. runtime errors and exceptions thrown while
1261executing a callback), this is not only highly event-loop specific, but
1262also not in any way wrapped by this module, as this is the job of the main
1263program.
1264
1265The pure perl event loop simply re-throws the exception (usually
1266within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
1267$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1268so on.
1269
1270=head1 ENVIRONMENT VARIABLES
1271
1272The following environment variables are used by this module or its
1273submodules:
1274
1275=over 4
1276
1277=item C<PERL_ANYEVENT_VERBOSE>
1278
1279By default, AnyEvent will be completely silent except in fatal
1280conditions. You can set this environment variable to make AnyEvent more
1281talkative.
1282
1283When set to C<1> or higher, causes AnyEvent to warn about unexpected
1284conditions, such as not being able to load the event model specified by
1285C<PERL_ANYEVENT_MODEL>.
1286
1287When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1288model it chooses.
1289
1290=item C<PERL_ANYEVENT_STRICT>
1291
1292AnyEvent does not do much argument checking by default, as thorough
1293argument checking is very costly. Setting this variable to a true value
1294will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1295check the arguments passed to most method calls. If it finds any problems
1296it will croak.
1297
1298In other words, enables "strict" mode.
1299
1300Unlike C<use strict>, it is definitely recommended ot keep it off in
1301production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
1302developing programs can be very useful, however.
1303
1304=item C<PERL_ANYEVENT_MODEL>
1305
1306This can be used to specify the event model to be used by AnyEvent, before
1307auto detection and -probing kicks in. It must be a string consisting
1308entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1309and the resulting module name is loaded and if the load was successful,
1310used as event model. If it fails to load AnyEvent will proceed with
1311auto detection and -probing.
1312
1313This functionality might change in future versions.
1314
1315For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1316could start your program like this:
1317
1318 PERL_ANYEVENT_MODEL=Perl perl ...
1319
1320=item C<PERL_ANYEVENT_PROTOCOLS>
1321
1322Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1323for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1324of auto probing).
1325
1326Must be set to a comma-separated list of protocols or address families,
1327current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1328used, and preference will be given to protocols mentioned earlier in the
1329list.
1330
1331This variable can effectively be used for denial-of-service attacks
1332against local programs (e.g. when setuid), although the impact is likely
1333small, as the program has to handle conenction and other failures anyways.
1334
1335Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1336but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1337- only support IPv4, never try to resolve or contact IPv6
1338addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1339IPv6, but prefer IPv6 over IPv4.
1340
1341=item C<PERL_ANYEVENT_EDNS0>
1342
1343Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1344for DNS. This extension is generally useful to reduce DNS traffic, but
1345some (broken) firewalls drop such DNS packets, which is why it is off by
1346default.
1347
1348Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1349EDNS0 in its DNS requests.
1350
1351=item C<PERL_ANYEVENT_MAX_FORKS>
1352
1353The maximum number of child processes that C<AnyEvent::Util::fork_call>
1354will create in parallel.
1355
1356=back
1357
1095=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1358=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1096 1359
1097This is an advanced topic that you do not normally need to use AnyEvent in 1360This is an advanced topic that you do not normally need to use AnyEvent in
1098a module. This section is only of use to event loop authors who want to 1361a module. This section is only of use to event loop authors who want to
1099provide AnyEvent compatibility. 1362provide AnyEvent compatibility.
1132 1395
1133I<rxvt-unicode> also cheats a bit by not providing blocking access to 1396I<rxvt-unicode> also cheats a bit by not providing blocking access to
1134condition variables: code blocking while waiting for a condition will 1397condition variables: code blocking while waiting for a condition will
1135C<die>. This still works with most modules/usages, and blocking calls must 1398C<die>. This still works with most modules/usages, and blocking calls must
1136not be done in an interactive application, so it makes sense. 1399not be done in an interactive application, so it makes sense.
1137
1138=head1 ENVIRONMENT VARIABLES
1139
1140The following environment variables are used by this module:
1141
1142=over 4
1143
1144=item C<PERL_ANYEVENT_VERBOSE>
1145
1146By default, AnyEvent will be completely silent except in fatal
1147conditions. You can set this environment variable to make AnyEvent more
1148talkative.
1149
1150When set to C<1> or higher, causes AnyEvent to warn about unexpected
1151conditions, such as not being able to load the event model specified by
1152C<PERL_ANYEVENT_MODEL>.
1153
1154When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1155model it chooses.
1156
1157=item C<PERL_ANYEVENT_MODEL>
1158
1159This can be used to specify the event model to be used by AnyEvent, before
1160auto detection and -probing kicks in. It must be a string consisting
1161entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1162and the resulting module name is loaded and if the load was successful,
1163used as event model. If it fails to load AnyEvent will proceed with
1164auto detection and -probing.
1165
1166This functionality might change in future versions.
1167
1168For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1169could start your program like this:
1170
1171 PERL_ANYEVENT_MODEL=Perl perl ...
1172
1173=item C<PERL_ANYEVENT_PROTOCOLS>
1174
1175Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1176for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1177of auto probing).
1178
1179Must be set to a comma-separated list of protocols or address families,
1180current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1181used, and preference will be given to protocols mentioned earlier in the
1182list.
1183
1184This variable can effectively be used for denial-of-service attacks
1185against local programs (e.g. when setuid), although the impact is likely
1186small, as the program has to handle connection errors already-
1187
1188Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1189but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1190- only support IPv4, never try to resolve or contact IPv6
1191addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1192IPv6, but prefer IPv6 over IPv4.
1193
1194=item C<PERL_ANYEVENT_EDNS0>
1195
1196Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1197for DNS. This extension is generally useful to reduce DNS traffic, but
1198some (broken) firewalls drop such DNS packets, which is why it is off by
1199default.
1200
1201Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1202EDNS0 in its DNS requests.
1203
1204=item C<PERL_ANYEVENT_MAX_FORKS>
1205
1206The maximum number of child processes that C<AnyEvent::Util::fork_call>
1207will create in parallel.
1208
1209=back
1210 1400
1211=head1 EXAMPLE PROGRAM 1401=head1 EXAMPLE PROGRAM
1212 1402
1213The following program uses an I/O watcher to read data from STDIN, a timer 1403The following program uses an I/O watcher to read data from STDIN, a timer
1214to display a message once per second, and a condition variable to quit the 1404to display a message once per second, and a condition variable to quit the
1408watcher. 1598watcher.
1409 1599
1410=head3 Results 1600=head3 Results
1411 1601
1412 name watchers bytes create invoke destroy comment 1602 name watchers bytes create invoke destroy comment
1413 EV/EV 400000 244 0.56 0.46 0.31 EV native interface 1603 EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1414 EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers 1604 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1415 CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal 1605 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1416 Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation 1606 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1417 Event/Event 16000 516 31.88 31.30 0.85 Event native interface 1607 Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1418 Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers 1608 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1419 Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour 1609 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1420 Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers 1610 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1421 POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event 1611 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1422 POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select 1612 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1423 1613
1424=head3 Discussion 1614=head3 Discussion
1425 1615
1426The benchmark does I<not> measure scalability of the event loop very 1616The benchmark does I<not> measure scalability of the event loop very
1427well. For example, a select-based event loop (such as the pure perl one) 1617well. For example, a select-based event loop (such as the pure perl one)
1629watchers, as the management overhead dominates. 1819watchers, as the management overhead dominates.
1630 1820
1631=back 1821=back
1632 1822
1633 1823
1824=head1 SIGNALS
1825
1826AnyEvent currently installs handlers for these signals:
1827
1828=over 4
1829
1830=item SIGCHLD
1831
1832A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1833emulation for event loops that do not support them natively. Also, some
1834event loops install a similar handler.
1835
1836=item SIGPIPE
1837
1838A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1839when AnyEvent gets loaded.
1840
1841The rationale for this is that AnyEvent users usually do not really depend
1842on SIGPIPE delivery (which is purely an optimisation for shell use, or
1843badly-written programs), but C<SIGPIPE> can cause spurious and rare
1844program exits as a lot of people do not expect C<SIGPIPE> when writing to
1845some random socket.
1846
1847The rationale for installing a no-op handler as opposed to ignoring it is
1848that this way, the handler will be restored to defaults on exec.
1849
1850Feel free to install your own handler, or reset it to defaults.
1851
1852=back
1853
1854=cut
1855
1856$SIG{PIPE} = sub { }
1857 unless defined $SIG{PIPE};
1858
1859
1634=head1 FORK 1860=head1 FORK
1635 1861
1636Most event libraries are not fork-safe. The ones who are usually are 1862Most event libraries are not fork-safe. The ones who are usually are
1637because they rely on inefficient but fork-safe C<select> or C<poll> 1863because they rely on inefficient but fork-safe C<select> or C<poll>
1638calls. Only L<EV> is fully fork-aware. 1864calls. Only L<EV> is fully fork-aware.
1651specified in the variable. 1877specified in the variable.
1652 1878
1653You can make AnyEvent completely ignore this variable by deleting it 1879You can make AnyEvent completely ignore this variable by deleting it
1654before the first watcher gets created, e.g. with a C<BEGIN> block: 1880before the first watcher gets created, e.g. with a C<BEGIN> block:
1655 1881
1656 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } 1882 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1657 1883
1658 use AnyEvent; 1884 use AnyEvent;
1659 1885
1660Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can 1886Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1661be used to probe what backend is used and gain other information (which is 1887be used to probe what backend is used and gain other information (which is
1662probably even less useful to an attacker than PERL_ANYEVENT_MODEL). 1888probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1889$ENV{PERL_ANYEGENT_STRICT}.
1890
1891
1892=head1 BUGS
1893
1894Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1895to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1896and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1897memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1898pronounced).
1663 1899
1664 1900
1665=head1 SEE ALSO 1901=head1 SEE ALSO
1666 1902
1667Utility functions: L<AnyEvent::Util>. 1903Utility functions: L<AnyEvent::Util>.
1684Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 1920Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1685 1921
1686 1922
1687=head1 AUTHOR 1923=head1 AUTHOR
1688 1924
1689 Marc Lehmann <schmorp@schmorp.de> 1925 Marc Lehmann <schmorp@schmorp.de>
1690 http://home.schmorp.de/ 1926 http://home.schmorp.de/
1691 1927
1692=cut 1928=cut
1693 1929
16941 19301
1695 1931

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