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Revision 1.214 by root, Mon Jun 22 11:57:05 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 and POE are various supported
6event loops.
6 7
7=head1 SYNOPSIS 8=head1 SYNOPSIS
8 9
9 use AnyEvent; 10 use AnyEvent;
10 11
12 # file descriptor readable
11 my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { 13 my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14
15 # one-shot or repeating timers
16 my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17 my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
18
19 print AnyEvent->now; # prints current event loop time
20 print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
21
22 # POSIX signal
23 my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
24
25 # child process exit
26 my $w = AnyEvent->child (pid => $pid, cb => sub {
27 my ($pid, $status) = @_;
12 ... 28 ...
13 }); 29 });
14 30
15 my $w = AnyEvent->timer (after => $seconds, cb => sub { 31 # called when event loop idle (if applicable)
16 ... 32 my $w = AnyEvent->idle (cb => sub { ... });
17 });
18 33
19 my $w = AnyEvent->condvar; # stores whether a condition was flagged 34 my $w = AnyEvent->condvar; # stores whether a condition was flagged
20 $w->send; # wake up current and all future recv's 35 $w->send; # wake up current and all future recv's
21 $w->recv; # enters "main loop" till $condvar gets ->send 36 $w->recv; # enters "main loop" till $condvar gets ->send
37 # use a condvar in callback mode:
38 $w->cb (sub { $_[0]->recv });
22 39
23=head1 INTRODUCTION/TUTORIAL 40=head1 INTRODUCTION/TUTORIAL
24 41
25This manpage is mainly a reference manual. If you are interested 42This manpage is mainly a reference manual. If you are interested
26in a tutorial or some gentle introduction, have a look at the 43in a tutorial or some gentle introduction, have a look at the
33 50
34Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of 51Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
35policy> and AnyEvent is I<small and efficient>. 52policy> and AnyEvent is I<small and efficient>.
36 53
37First and foremost, I<AnyEvent is not an event model> itself, it only 54First and foremost, I<AnyEvent is not an event model> itself, it only
38interfaces to whatever event model the main program happens to use in a 55interfaces to whatever event model the main program happens to use, in a
39pragmatic way. For event models and certain classes of immortals alike, 56pragmatic way. For event models and certain classes of immortals alike,
40the statement "there can only be one" is a bitter reality: In general, 57the statement "there can only be one" is a bitter reality: In general,
41only one event loop can be active at the same time in a process. AnyEvent 58only one event loop can be active at the same time in a process. AnyEvent
42helps hiding the differences between those event loops. 59cannot change this, but it can hide the differences between those event
60loops.
43 61
44The goal of AnyEvent is to offer module authors the ability to do event 62The goal of AnyEvent is to offer module authors the ability to do event
45programming (waiting for I/O or timer events) without subscribing to a 63programming (waiting for I/O or timer events) without subscribing to a
46religion, a way of living, and most importantly: without forcing your 64religion, a way of living, and most importantly: without forcing your
47module users into the same thing by forcing them to use the same event 65module users into the same thing by forcing them to use the same event
48model you use. 66model you use.
49 67
50For modules like POE or IO::Async (which is a total misnomer as it is 68For modules like POE or IO::Async (which is a total misnomer as it is
51actually doing all I/O I<synchronously>...), using them in your module is 69actually doing all I/O I<synchronously>...), using them in your module is
52like joining a cult: After you joined, you are dependent on them and you 70like joining a cult: After you joined, you are dependent on them and you
53cannot use anything else, as it is simply incompatible to everything that 71cannot use anything else, as they are simply incompatible to everything
54isn't itself. What's worse, all the potential users of your module are 72that isn't them. What's worse, all the potential users of your
55I<also> forced to use the same event loop you use. 73module are I<also> forced to use the same event loop you use.
56 74
57AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works 75AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
58fine. AnyEvent + Tk works fine etc. etc. but none of these work together 76fine. AnyEvent + Tk works fine etc. etc. but none of these work together
59with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if 77with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
60your module uses one of those, every user of your module has to use it, 78your module uses one of those, every user of your module has to use it,
61too. But if your module uses AnyEvent, it works transparently with all 79too. But if your module uses AnyEvent, it works transparently with all
62event models it supports (including stuff like POE and IO::Async, as long 80event models it supports (including stuff like IO::Async, as long as those
63as those use one of the supported event loops. It is trivial to add new 81use one of the supported event loops. It is trivial to add new event loops
64event loops to AnyEvent, too, so it is future-proof). 82to AnyEvent, too, so it is future-proof).
65 83
66In addition to being free of having to use I<the one and only true event 84In addition to being free of having to use I<the one and only true event
67model>, AnyEvent also is free of bloat and policy: with POE or similar 85model>, AnyEvent also is free of bloat and policy: with POE or similar
68modules, you get an enormous amount of code and strict rules you have to 86modules, you get an enormous amount of code and strict rules you have to
69follow. AnyEvent, on the other hand, is lean and up to the point, by only 87follow. AnyEvent, on the other hand, is lean and up to the point, by only
127These watchers are normal Perl objects with normal Perl lifetime. After 145These watchers are normal Perl objects with normal Perl lifetime. After
128creating a watcher it will immediately "watch" for events and invoke the 146creating a watcher it will immediately "watch" for events and invoke the
129callback when the event occurs (of course, only when the event model 147callback when the event occurs (of course, only when the event model
130is in control). 148is in control).
131 149
150Note that B<callbacks must not permanently change global variables>
151potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
152callbacks must not C<die> >>. The former is good programming practise in
153Perl and the latter stems from the fact that exception handling differs
154widely between event loops.
155
132To disable the watcher you have to destroy it (e.g. by setting the 156To disable the watcher you have to destroy it (e.g. by setting the
133variable you store it in to C<undef> or otherwise deleting all references 157variable you store it in to C<undef> or otherwise deleting all references
134to it). 158to it).
135 159
136All watchers are created by calling a method on the C<AnyEvent> class. 160All watchers are created by calling a method on the C<AnyEvent> class.
152=head2 I/O WATCHERS 176=head2 I/O WATCHERS
153 177
154You can create an I/O watcher by calling the C<< AnyEvent->io >> method 178You can create an I/O watcher by calling the C<< AnyEvent->io >> method
155with the following mandatory key-value pairs as arguments: 179with the following mandatory key-value pairs as arguments:
156 180
157C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events 181C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
158(AnyEvent might or might not keep a reference to this file handle). C<poll> 182for events (AnyEvent might or might not keep a reference to this file
183handle). Note that only file handles pointing to things for which
184non-blocking operation makes sense are allowed. This includes sockets,
185most character devices, pipes, fifos and so on, but not for example files
186or block devices.
187
159must be a string that is either C<r> or C<w>, which creates a watcher 188C<poll> must be a string that is either C<r> or C<w>, which creates a
160waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the 189watcher waiting for "r"eadable or "w"ritable events, respectively.
190
161callback to invoke each time the file handle becomes ready. 191C<cb> is the callback to invoke each time the file handle becomes ready.
162 192
163Although the callback might get passed parameters, their value and 193Although the callback might get passed parameters, their value and
164presence is undefined and you cannot rely on them. Portable AnyEvent 194presence is undefined and you cannot rely on them. Portable AnyEvent
165callbacks cannot use arguments passed to I/O watcher callbacks. 195callbacks cannot use arguments passed to I/O watcher callbacks.
166 196
298In either case, if you care (and in most cases, you don't), then you 328In either case, if you care (and in most cases, you don't), then you
299can get whatever behaviour you want with any event loop, by taking the 329can get whatever behaviour you want with any event loop, by taking the
300difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into 330difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
301account. 331account.
302 332
333=item AnyEvent->now_update
334
335Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
336the current time for each loop iteration (see the discussion of L<<
337AnyEvent->now >>, above).
338
339When a callback runs for a long time (or when the process sleeps), then
340this "current" time will differ substantially from the real time, which
341might affect timers and time-outs.
342
343When this is the case, you can call this method, which will update the
344event loop's idea of "current time".
345
346Note that updating the time I<might> cause some events to be handled.
347
303=back 348=back
304 349
305=head2 SIGNAL WATCHERS 350=head2 SIGNAL WATCHERS
306 351
307You can watch for signals using a signal watcher, C<signal> is the signal 352You can watch for signals using a signal watcher, C<signal> is the signal
308I<name> without any C<SIG> prefix, C<cb> is the Perl callback to 353I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
309be invoked whenever a signal occurs. 354callback to be invoked whenever a signal occurs.
310 355
311Although the callback might get passed parameters, their value and 356Although the callback might get passed parameters, their value and
312presence is undefined and you cannot rely on them. Portable AnyEvent 357presence is undefined and you cannot rely on them. Portable AnyEvent
313callbacks cannot use arguments passed to signal watcher callbacks. 358callbacks cannot use arguments passed to signal watcher callbacks.
314 359
330=head2 CHILD PROCESS WATCHERS 375=head2 CHILD PROCESS WATCHERS
331 376
332You can also watch on a child process exit and catch its exit status. 377You can also watch on a child process exit and catch its exit status.
333 378
334The child process is specified by the C<pid> argument (if set to C<0>, it 379The child process is specified by the C<pid> argument (if set to C<0>, it
335watches for any child process exit). The watcher will trigger as often 380watches for any child process exit). The watcher will triggered only when
336as status change for the child are received. This works by installing a 381the child process has finished and an exit status is available, not on
337signal handler for C<SIGCHLD>. The callback will be called with the pid 382any trace events (stopped/continued).
338and exit status (as returned by waitpid), so unlike other watcher types, 383
339you I<can> rely on child watcher callback arguments. 384The 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
386callback arguments.
387
388This watcher type works by installing a signal handler for C<SIGCHLD>,
389and since it cannot be shared, nothing else should use SIGCHLD or reap
390random child processes (waiting for specific child processes, e.g. inside
391C<system>, is just fine).
340 392
341There is a slight catch to child watchers, however: you usually start them 393There is a slight catch to child watchers, however: you usually start them
342I<after> the child process was created, and this means the process could 394I<after> the child process was created, and this means the process could
343have exited already (and no SIGCHLD will be sent anymore). 395have exited already (and no SIGCHLD will be sent anymore).
344 396
366 ); 418 );
367 419
368 # do something else, then wait for process exit 420 # do something else, then wait for process exit
369 $done->recv; 421 $done->recv;
370 422
423=head2 IDLE WATCHERS
424
425Sometimes there is a need to do something, but it is not so important
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
430Idle watchers ideally get invoked when the event loop has nothing
431better to do, just before it would block the process to wait for new
432events. Instead of blocking, the idle watcher is invoked.
433
434Most event loops unfortunately do not really support idle watchers (only
435EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
436will simply call the callback "from time to time".
437
438Example: read lines from STDIN, but only process them when the
439program is otherwise idle:
440
441 my @lines; # read data
442 my $idle_w;
443 my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
444 push @lines, scalar <STDIN>;
445
446 # start an idle watcher, if not already done
447 $idle_w ||= AnyEvent->idle (cb => sub {
448 # handle only one line, when there are lines left
449 if (my $line = shift @lines) {
450 print "handled when idle: $line";
451 } else {
452 # otherwise disable the idle watcher again
453 undef $idle_w;
454 }
455 });
456 });
457
371=head2 CONDITION VARIABLES 458=head2 CONDITION VARIABLES
372 459
373If you are familiar with some event loops you will know that all of them 460If you are familiar with some event loops you will know that all of them
374require you to run some blocking "loop", "run" or similar function that 461require you to run some blocking "loop", "run" or similar function that
375will actively watch for new events and call your callbacks. 462will actively watch for new events and call your callbacks.
380The instrument to do that is called a "condition variable", so called 467The instrument to do that is called a "condition variable", so called
381because they represent a condition that must become true. 468because they represent a condition that must become true.
382 469
383Condition variables can be created by calling the C<< AnyEvent->condvar 470Condition variables can be created by calling the C<< AnyEvent->condvar
384>> method, usually without arguments. The only argument pair allowed is 471>> method, usually without arguments. The only argument pair allowed is
472
385C<cb>, which specifies a callback to be called when the condition variable 473C<cb>, which specifies a callback to be called when the condition variable
386becomes true. 474becomes true, with the condition variable as the first argument (but not
475the results).
387 476
388After creation, the condition variable is "false" until it becomes "true" 477After creation, the condition variable is "false" until it becomes "true"
389by calling the C<send> method (or calling the condition variable as if it 478by calling the C<send> method (or calling the condition variable as if it
390were a callback, read about the caveats in the description for the C<< 479were a callback, read about the caveats in the description for the C<<
391->send >> method). 480->send >> method).
447 536
448 my $done = AnyEvent->condvar; 537 my $done = AnyEvent->condvar;
449 my $delay = AnyEvent->timer (after => 5, cb => $done); 538 my $delay = AnyEvent->timer (after => 5, cb => $done);
450 $done->recv; 539 $done->recv;
451 540
541Example: Imagine an API that returns a condvar and doesn't support
542callbacks. This is how you make a synchronous call, for example from
543the main program:
544
545 use AnyEvent::CouchDB;
546
547 ...
548
549 my @info = $couchdb->info->recv;
550
551And this is how you would just ste a callback to be called whenever the
552results are available:
553
554 $couchdb->info->cb (sub {
555 my @info = $_[0]->recv;
556 });
557
452=head3 METHODS FOR PRODUCERS 558=head3 METHODS FOR PRODUCERS
453 559
454These methods should only be used by the producing side, i.e. the 560These methods should only be used by the producing side, i.e. the
455code/module that eventually sends the signal. Note that it is also 561code/module that eventually sends the signal. Note that it is also
456the producer side which creates the condvar in most cases, but it isn't 562the producer side which creates the condvar in most cases, but it isn't
589=item $bool = $cv->ready 695=item $bool = $cv->ready
590 696
591Returns true when the condition is "true", i.e. whether C<send> or 697Returns true when the condition is "true", i.e. whether C<send> or
592C<croak> have been called. 698C<croak> have been called.
593 699
594=item $cb = $cv->cb ([new callback]) 700=item $cb = $cv->cb ($cb->($cv))
595 701
596This is a mutator function that returns the callback set and optionally 702This is a mutator function that returns the callback set and optionally
597replaces it before doing so. 703replaces it before doing so.
598 704
599The callback will be called when the condition becomes "true", i.e. when 705The callback will be called when the condition becomes "true", i.e. when
789=item L<AnyEvent::IGS> 895=item L<AnyEvent::IGS>
790 896
791A non-blocking interface to the Internet Go Server protocol (used by 897A non-blocking interface to the Internet Go Server protocol (used by
792L<App::IGS>). 898L<App::IGS>).
793 899
794=item L<Net::IRC3> 900=item L<AnyEvent::IRC>
795 901
796AnyEvent based IRC client module family. 902AnyEvent based IRC client module family (replacing the older Net::IRC3).
797 903
798=item L<Net::XMPP2> 904=item L<Net::XMPP2>
799 905
800AnyEvent based XMPP (Jabber protocol) module family. 906AnyEvent based XMPP (Jabber protocol) module family.
801 907
821=cut 927=cut
822 928
823package AnyEvent; 929package AnyEvent;
824 930
825no warnings; 931no warnings;
826use strict; 932use strict qw(vars subs);
827 933
828use Carp; 934use Carp;
829 935
830our $VERSION = 4.2; 936our $VERSION = 4.411;
831our $MODEL; 937our $MODEL;
832 938
833our $AUTOLOAD; 939our $AUTOLOAD;
834our @ISA; 940our @ISA;
835 941
836our @REGISTRY; 942our @REGISTRY;
837 943
838our $WIN32; 944our $WIN32;
839 945
840BEGIN { 946BEGIN {
841 my $win32 = ! ! ($^O =~ /mswin32/i); 947 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
842 eval "sub WIN32(){ $win32 }"; 948 eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
949
950 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
951 if ${^TAINT};
843} 952}
844 953
845our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 954our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
846 955
847our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 956our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
867 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 976 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
868 [Wx:: => AnyEvent::Impl::POE::], 977 [Wx:: => AnyEvent::Impl::POE::],
869 [Prima:: => AnyEvent::Impl::POE::], 978 [Prima:: => AnyEvent::Impl::POE::],
870); 979);
871 980
872our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY); 981our %method = map +($_ => 1),
982 qw(io timer time now now_update signal child idle condvar one_event DESTROY);
873 983
874our @post_detect; 984our @post_detect;
875 985
876sub post_detect(&) { 986sub post_detect(&) {
877 my ($cb) = @_; 987 my ($cb) = @_;
882 1 992 1
883 } else { 993 } else {
884 push @post_detect, $cb; 994 push @post_detect, $cb;
885 995
886 defined wantarray 996 defined wantarray
887 ? bless \$cb, "AnyEvent::Util::PostDetect" 997 ? bless \$cb, "AnyEvent::Util::postdetect"
888 : () 998 : ()
889 } 999 }
890} 1000}
891 1001
892sub AnyEvent::Util::PostDetect::DESTROY { 1002sub AnyEvent::Util::postdetect::DESTROY {
893 @post_detect = grep $_ != ${$_[0]}, @post_detect; 1003 @post_detect = grep $_ != ${$_[0]}, @post_detect;
894} 1004}
895 1005
896sub detect() { 1006sub detect() {
897 unless ($MODEL) { 1007 unless ($MODEL) {
934 last; 1044 last;
935 } 1045 }
936 } 1046 }
937 1047
938 $MODEL 1048 $MODEL
939 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib."; 1049 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
940 } 1050 }
941 } 1051 }
942 1052
1053 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1054
943 unshift @ISA, $MODEL; 1055 unshift @ISA, $MODEL;
944 push @{"$MODEL\::ISA"}, "AnyEvent::Base"; 1056
1057 require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
945 1058
946 (shift @post_detect)->() while @post_detect; 1059 (shift @post_detect)->() while @post_detect;
947 } 1060 }
948 1061
949 $MODEL 1062 $MODEL
959 1072
960 my $class = shift; 1073 my $class = shift;
961 $class->$func (@_); 1074 $class->$func (@_);
962} 1075}
963 1076
1077# utility function to dup a filehandle. this is used by many backends
1078# 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).
1080sub _dupfh($$$$) {
1081 my ($poll, $fh, $r, $w) = @_;
1082
1083 # cygwin requires the fh mode to be matching, unix doesn't
1084 my ($rw, $mode) = $poll eq "r" ? ($r, "<")
1085 : $poll eq "w" ? ($w, ">")
1086 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1087
1088 open my $fh2, "$mode&" . fileno $fh
1089 or die "cannot dup() filehandle: $!,";
1090
1091 # we assume CLOEXEC is already set by perl in all important cases
1092
1093 ($fh2, $rw)
1094}
1095
964package AnyEvent::Base; 1096package AnyEvent::Base;
965 1097
966# default implementation for now and time 1098# default implementations for many methods
967 1099
968use Time::HiRes (); 1100BEGIN {
1101 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1102 *_time = \&Time::HiRes::time;
1103 # if (eval "use POSIX (); (POSIX::times())...
1104 } else {
1105 *_time = sub { time }; # epic fail
1106 }
1107}
969 1108
970sub time { Time::HiRes::time } 1109sub time { _time }
971sub now { Time::HiRes::time } 1110sub now { _time }
1111sub now_update { }
972 1112
973# default implementation for ->condvar 1113# default implementation for ->condvar
974 1114
975sub condvar { 1115sub condvar {
976 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: 1116 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
977} 1117}
978 1118
979# default implementation for ->signal 1119# default implementation for ->signal
980 1120
981our %SIG_CB; 1121our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1122
1123sub _signal_exec {
1124 sysread $SIGPIPE_R, my $dummy, 4;
1125
1126 while (%SIG_EV) {
1127 for (keys %SIG_EV) {
1128 delete $SIG_EV{$_};
1129 $_->() for values %{ $SIG_CB{$_} || {} };
1130 }
1131 }
1132}
982 1133
983sub signal { 1134sub signal {
984 my (undef, %arg) = @_; 1135 my (undef, %arg) = @_;
985 1136
1137 unless ($SIGPIPE_R) {
1138 require Fcntl;
1139
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 {
1147 pipe $SIGPIPE_R, $SIGPIPE_W;
1148 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
1150
1151 # not strictly required, as $^F is normally 2, but let's make sure...
1152 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1153 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1154 }
1155
1156 $SIGPIPE_R
1157 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1158
1159 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1160 }
1161
986 my $signal = uc $arg{signal} 1162 my $signal = uc $arg{signal}
987 or Carp::croak "required option 'signal' is missing"; 1163 or Carp::croak "required option 'signal' is missing";
988 1164
989 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1165 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
990 $SIG{$signal} ||= sub { 1166 $SIG{$signal} ||= sub {
991 $_->() for values %{ $SIG_CB{$signal} || {} }; 1167 local $!;
1168 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1169 undef $SIG_EV{$signal};
992 }; 1170 };
993 1171
994 bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" 1172 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
995} 1173}
996 1174
997sub AnyEvent::Base::Signal::DESTROY { 1175sub AnyEvent::Base::signal::DESTROY {
998 my ($signal, $cb) = @{$_[0]}; 1176 my ($signal, $cb) = @{$_[0]};
999 1177
1000 delete $SIG_CB{$signal}{$cb}; 1178 delete $SIG_CB{$signal}{$cb};
1001 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.
1002 delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} }; 1183 undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1003} 1184}
1004 1185
1005# default implementation for ->child 1186# default implementation for ->child
1006 1187
1007our %PID_CB; 1188our %PID_CB;
1008our $CHLD_W; 1189our $CHLD_W;
1009our $CHLD_DELAY_W; 1190our $CHLD_DELAY_W;
1010our $PID_IDLE;
1011our $WNOHANG; 1191our $WNOHANG;
1012 1192
1013sub _child_wait { 1193sub _sigchld {
1014 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 1194 while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1015 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), 1195 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),
1016 (values %{ $PID_CB{0} || {} }); 1196 (values %{ $PID_CB{0} || {} });
1017 } 1197 }
1018
1019 undef $PID_IDLE;
1020}
1021
1022sub _sigchld {
1023 # make sure we deliver these changes "synchronous" with the event loop.
1024 $CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1025 undef $CHLD_DELAY_W;
1026 &_child_wait;
1027 });
1028} 1198}
1029 1199
1030sub child { 1200sub child {
1031 my (undef, %arg) = @_; 1201 my (undef, %arg) = @_;
1032 1202
1033 defined (my $pid = $arg{pid} + 0) 1203 defined (my $pid = $arg{pid} + 0)
1034 or Carp::croak "required option 'pid' is missing"; 1204 or Carp::croak "required option 'pid' is missing";
1035 1205
1036 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1206 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
1037 1207
1038 unless ($WNOHANG) {
1039 $WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; 1208 $WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1040 }
1041 1209
1042 unless ($CHLD_W) { 1210 unless ($CHLD_W) {
1043 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1211 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1044 # child could be a zombie already, so make at least one round 1212 # child could be a zombie already, so make at least one round
1045 &_sigchld; 1213 &_sigchld;
1046 } 1214 }
1047 1215
1048 bless [$pid, $arg{cb}], "AnyEvent::Base::Child" 1216 bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1049} 1217}
1050 1218
1051sub AnyEvent::Base::Child::DESTROY { 1219sub AnyEvent::Base::child::DESTROY {
1052 my ($pid, $cb) = @{$_[0]}; 1220 my ($pid, $cb) = @{$_[0]};
1053 1221
1054 delete $PID_CB{$pid}{$cb}; 1222 delete $PID_CB{$pid}{$cb};
1055 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 1223 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1056 1224
1057 undef $CHLD_W unless keys %PID_CB; 1225 undef $CHLD_W unless keys %PID_CB;
1226}
1227
1228# idle emulation is done by simply using a timer, regardless
1229# of whether the process is idle or not, and not letting
1230# the callback use more than 50% of the time.
1231sub idle {
1232 my (undef, %arg) = @_;
1233
1234 my ($cb, $w, $rcb) = $arg{cb};
1235
1236 $rcb = sub {
1237 if ($cb) {
1238 $w = _time;
1239 &$cb;
1240 $w = _time - $w;
1241
1242 # never use more then 50% of the time for the idle watcher,
1243 # within some limits
1244 $w = 0.0001 if $w < 0.0001;
1245 $w = 5 if $w > 5;
1246
1247 $w = AnyEvent->timer (after => $w, cb => $rcb);
1248 } else {
1249 # clean up...
1250 undef $w;
1251 undef $rcb;
1252 }
1253 };
1254
1255 $w = AnyEvent->timer (after => 0.05, cb => $rcb);
1256
1257 bless \\$cb, "AnyEvent::Base::idle"
1258}
1259
1260sub AnyEvent::Base::idle::DESTROY {
1261 undef $${$_[0]};
1058} 1262}
1059 1263
1060package AnyEvent::CondVar; 1264package AnyEvent::CondVar;
1061 1265
1062our @ISA = AnyEvent::CondVar::Base::; 1266our @ISA = AnyEvent::CondVar::Base::;
1114} 1318}
1115 1319
1116# undocumented/compatibility with pre-3.4 1320# undocumented/compatibility with pre-3.4
1117*broadcast = \&send; 1321*broadcast = \&send;
1118*wait = \&_wait; 1322*wait = \&_wait;
1323
1324=head1 ERROR AND EXCEPTION HANDLING
1325
1326In general, AnyEvent does not do any error handling - it relies on the
1327caller to do that if required. The L<AnyEvent::Strict> module (see also
1328the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
1329checking of all AnyEvent methods, however, which is highly useful during
1330development.
1331
1332As for exception handling (i.e. runtime errors and exceptions thrown while
1333executing a callback), this is not only highly event-loop specific, but
1334also not in any way wrapped by this module, as this is the job of the main
1335program.
1336
1337The pure perl event loop simply re-throws the exception (usually
1338within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
1339$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1340so on.
1341
1342=head1 ENVIRONMENT VARIABLES
1343
1344The following environment variables are used by this module or its
1345submodules.
1346
1347Note that AnyEvent will remove I<all> environment variables starting with
1348C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
1349enabled.
1350
1351=over 4
1352
1353=item C<PERL_ANYEVENT_VERBOSE>
1354
1355By default, AnyEvent will be completely silent except in fatal
1356conditions. You can set this environment variable to make AnyEvent more
1357talkative.
1358
1359When set to C<1> or higher, causes AnyEvent to warn about unexpected
1360conditions, such as not being able to load the event model specified by
1361C<PERL_ANYEVENT_MODEL>.
1362
1363When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1364model it chooses.
1365
1366=item C<PERL_ANYEVENT_STRICT>
1367
1368AnyEvent does not do much argument checking by default, as thorough
1369argument checking is very costly. Setting this variable to a true value
1370will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1371check the arguments passed to most method calls. If it finds any problems
1372it will croak.
1373
1374In other words, enables "strict" mode.
1375
1376Unlike C<use strict>, it is definitely recommended ot keep it off in
1377production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
1378developing programs can be very useful, however.
1379
1380=item C<PERL_ANYEVENT_MODEL>
1381
1382This 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
1384entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1385and the resulting module name is loaded and if the load was successful,
1386used as event model. If it fails to load AnyEvent will proceed with
1387auto detection and -probing.
1388
1389This functionality might change in future versions.
1390
1391For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1392could start your program like this:
1393
1394 PERL_ANYEVENT_MODEL=Perl perl ...
1395
1396=item C<PERL_ANYEVENT_PROTOCOLS>
1397
1398Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1399for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1400of auto probing).
1401
1402Must be set to a comma-separated list of protocols or address families,
1403current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1404used, and preference will be given to protocols mentioned earlier in the
1405list.
1406
1407This variable can effectively be used for denial-of-service attacks
1408against local programs (e.g. when setuid), although the impact is likely
1409small, as the program has to handle conenction and other failures anyways.
1410
1411Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1412but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1413- only support IPv4, never try to resolve or contact IPv6
1414addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1415IPv6, but prefer IPv6 over IPv4.
1416
1417=item C<PERL_ANYEVENT_EDNS0>
1418
1419Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1420for DNS. This extension is generally useful to reduce DNS traffic, but
1421some (broken) firewalls drop such DNS packets, which is why it is off by
1422default.
1423
1424Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1425EDNS0 in its DNS requests.
1426
1427=item C<PERL_ANYEVENT_MAX_FORKS>
1428
1429The maximum number of child processes that C<AnyEvent::Util::fork_call>
1430will create in parallel.
1431
1432=back
1119 1433
1120=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1434=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1121 1435
1122This is an advanced topic that you do not normally need to use AnyEvent in 1436This is an advanced topic that you do not normally need to use AnyEvent in
1123a module. This section is only of use to event loop authors who want to 1437a module. This section is only of use to event loop authors who want to
1157 1471
1158I<rxvt-unicode> also cheats a bit by not providing blocking access to 1472I<rxvt-unicode> also cheats a bit by not providing blocking access to
1159condition variables: code blocking while waiting for a condition will 1473condition variables: code blocking while waiting for a condition will
1160C<die>. This still works with most modules/usages, and blocking calls must 1474C<die>. This still works with most modules/usages, and blocking calls must
1161not be done in an interactive application, so it makes sense. 1475not be done in an interactive application, so it makes sense.
1162
1163=head1 ENVIRONMENT VARIABLES
1164
1165The following environment variables are used by this module:
1166
1167=over 4
1168
1169=item C<PERL_ANYEVENT_VERBOSE>
1170
1171By default, AnyEvent will be completely silent except in fatal
1172conditions. You can set this environment variable to make AnyEvent more
1173talkative.
1174
1175When set to C<1> or higher, causes AnyEvent to warn about unexpected
1176conditions, such as not being able to load the event model specified by
1177C<PERL_ANYEVENT_MODEL>.
1178
1179When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1180model it chooses.
1181
1182=item C<PERL_ANYEVENT_MODEL>
1183
1184This can be used to specify the event model to be used by AnyEvent, before
1185auto detection and -probing kicks in. It must be a string consisting
1186entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1187and the resulting module name is loaded and if the load was successful,
1188used as event model. If it fails to load AnyEvent will proceed with
1189auto detection and -probing.
1190
1191This functionality might change in future versions.
1192
1193For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1194could start your program like this:
1195
1196 PERL_ANYEVENT_MODEL=Perl perl ...
1197
1198=item C<PERL_ANYEVENT_PROTOCOLS>
1199
1200Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1201for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1202of auto probing).
1203
1204Must be set to a comma-separated list of protocols or address families,
1205current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1206used, and preference will be given to protocols mentioned earlier in the
1207list.
1208
1209This variable can effectively be used for denial-of-service attacks
1210against local programs (e.g. when setuid), although the impact is likely
1211small, as the program has to handle connection errors already-
1212
1213Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1214but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1215- only support IPv4, never try to resolve or contact IPv6
1216addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1217IPv6, but prefer IPv6 over IPv4.
1218
1219=item C<PERL_ANYEVENT_EDNS0>
1220
1221Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1222for DNS. This extension is generally useful to reduce DNS traffic, but
1223some (broken) firewalls drop such DNS packets, which is why it is off by
1224default.
1225
1226Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1227EDNS0 in its DNS requests.
1228
1229=item C<PERL_ANYEVENT_MAX_FORKS>
1230
1231The maximum number of child processes that C<AnyEvent::Util::fork_call>
1232will create in parallel.
1233
1234=back
1235 1476
1236=head1 EXAMPLE PROGRAM 1477=head1 EXAMPLE PROGRAM
1237 1478
1238The following program uses an I/O watcher to read data from STDIN, a timer 1479The following program uses an I/O watcher to read data from STDIN, a timer
1239to display a message once per second, and a condition variable to quit the 1480to display a message once per second, and a condition variable to quit the
1433watcher. 1674watcher.
1434 1675
1435=head3 Results 1676=head3 Results
1436 1677
1437 name watchers bytes create invoke destroy comment 1678 name watchers bytes create invoke destroy comment
1438 EV/EV 400000 244 0.56 0.46 0.31 EV native interface 1679 EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1439 EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers 1680 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1440 CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal 1681 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1441 Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation 1682 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1442 Event/Event 16000 516 31.88 31.30 0.85 Event native interface 1683 Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1443 Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers 1684 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1444 Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour 1685 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1445 Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers 1686 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1446 POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event 1687 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1447 POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select 1688 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1448 1689
1449=head3 Discussion 1690=head3 Discussion
1450 1691
1451The benchmark does I<not> measure scalability of the event loop very 1692The benchmark does I<not> measure scalability of the event loop very
1452well. For example, a select-based event loop (such as the pure perl one) 1693well. For example, a select-based event loop (such as the pure perl one)
1654watchers, as the management overhead dominates. 1895watchers, as the management overhead dominates.
1655 1896
1656=back 1897=back
1657 1898
1658 1899
1900=head1 SIGNALS
1901
1902AnyEvent currently installs handlers for these signals:
1903
1904=over 4
1905
1906=item SIGCHLD
1907
1908A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1909emulation for event loops that do not support them natively. Also, some
1910event loops install a similar handler.
1911
1912=item SIGPIPE
1913
1914A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1915when AnyEvent gets loaded.
1916
1917The rationale for this is that AnyEvent users usually do not really depend
1918on SIGPIPE delivery (which is purely an optimisation for shell use, or
1919badly-written programs), but C<SIGPIPE> can cause spurious and rare
1920program exits as a lot of people do not expect C<SIGPIPE> when writing to
1921some random socket.
1922
1923The rationale for installing a no-op handler as opposed to ignoring it is
1924that this way, the handler will be restored to defaults on exec.
1925
1926Feel free to install your own handler, or reset it to defaults.
1927
1928=back
1929
1930=cut
1931
1932$SIG{PIPE} = sub { }
1933 unless defined $SIG{PIPE};
1934
1935
1659=head1 FORK 1936=head1 FORK
1660 1937
1661Most event libraries are not fork-safe. The ones who are usually are 1938Most event libraries are not fork-safe. The ones who are usually are
1662because they rely on inefficient but fork-safe C<select> or C<poll> 1939because they rely on inefficient but fork-safe C<select> or C<poll>
1663calls. Only L<EV> is fully fork-aware. 1940calls. Only L<EV> is fully fork-aware.
1682 1959
1683 use AnyEvent; 1960 use AnyEvent;
1684 1961
1685Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can 1962Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1686be used to probe what backend is used and gain other information (which is 1963be used to probe what backend is used and gain other information (which is
1687probably even less useful to an attacker than PERL_ANYEVENT_MODEL). 1964probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1965$ENV{PERL_ANYEVENT_STRICT}.
1688 1966
1689 1967
1690=head1 BUGS 1968=head1 BUGS
1691 1969
1692Perl 5.8 has numerous memleaks that sometimes hit this module and are hard 1970Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1693to work around. If you suffer from memleaks, first upgrade to Perl 5.10 1971to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1694and check wether the leaks still show up. (Perl 5.10.0 has other annoying 1972and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1695mamleaks, such as leaking on C<map> and C<grep> but it is usually not as 1973memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1696pronounced). 1974pronounced).
1697 1975
1698 1976
1699=head1 SEE ALSO 1977=head1 SEE ALSO
1700 1978

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