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Revision 1.180 by root, Sat Sep 6 07:00:45 2008 UTC vs.
Revision 1.199 by root, Fri Mar 27 10:49:50 2009 UTC

137These watchers are normal Perl objects with normal Perl lifetime. After 137These watchers are normal Perl objects with normal Perl lifetime. After
138creating a watcher it will immediately "watch" for events and invoke the 138creating a watcher it will immediately "watch" for events and invoke the
139callback when the event occurs (of course, only when the event model 139callback when the event occurs (of course, only when the event model
140is in control). 140is in control).
141 141
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
142To 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
143variable 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
144to it). 150to it).
145 151
146All 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.
162=head2 I/O WATCHERS 168=head2 I/O WATCHERS
163 169
164You 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
165with the following mandatory key-value pairs as arguments: 171with the following mandatory key-value pairs as arguments:
166 172
167C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events 173C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
168(AnyEvent might or might not keep a reference to this file handle). C<poll> 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
169must be a string that is either C<r> or C<w>, which creates a watcher 180C<poll> must be a string that is either C<r> or C<w>, which creates a
170waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the 181watcher waiting for "r"eadable or "w"ritable events, respectively.
182
171callback to invoke each time the file handle becomes ready. 183C<cb> is the callback to invoke each time the file handle becomes ready.
172 184
173Although the callback might get passed parameters, their value and 185Although the callback might get passed parameters, their value and
174presence is undefined and you cannot rely on them. Portable AnyEvent 186presence is undefined and you cannot rely on them. Portable AnyEvent
175callbacks cannot use arguments passed to I/O watcher callbacks. 187callbacks cannot use arguments passed to I/O watcher callbacks.
176 188
340=head2 CHILD PROCESS WATCHERS 352=head2 CHILD PROCESS WATCHERS
341 353
342You can also watch on a child process exit and catch its exit status. 354You can also watch on a child process exit and catch its exit status.
343 355
344The child process is specified by the C<pid> argument (if set to C<0>, it 356The child process is specified by the C<pid> argument (if set to C<0>, it
345watches for any child process exit). The watcher will trigger as often 357watches for any child process exit). The watcher will triggered only when
346as status change for the child are received. This works by installing a 358the child process has finished and an exit status is available, not on
347signal handler for C<SIGCHLD>. The callback will be called with the pid 359any trace events (stopped/continued).
348and exit status (as returned by waitpid), so unlike other watcher types, 360
349you I<can> rely on child watcher callback arguments. 361The callback will be called with the pid and exit status (as returned by
362waitpid), so unlike other watcher types, you I<can> rely on child watcher
363callback arguments.
364
365This watcher type works by installing a signal handler for C<SIGCHLD>,
366and since it cannot be shared, nothing else should use SIGCHLD or reap
367random child processes (waiting for specific child processes, e.g. inside
368C<system>, is just fine).
350 369
351There is a slight catch to child watchers, however: you usually start them 370There is a slight catch to child watchers, however: you usually start them
352I<after> the child process was created, and this means the process could 371I<after> the child process was created, and this means the process could
353have exited already (and no SIGCHLD will be sent anymore). 372have exited already (and no SIGCHLD will be sent anymore).
354 373
818=item L<AnyEvent::IGS> 837=item L<AnyEvent::IGS>
819 838
820A non-blocking interface to the Internet Go Server protocol (used by 839A non-blocking interface to the Internet Go Server protocol (used by
821L<App::IGS>). 840L<App::IGS>).
822 841
823=item L<Net::IRC3> 842=item L<AnyEvent::IRC>
824 843
825AnyEvent based IRC client module family. 844AnyEvent based IRC client module family (replacing the older Net::IRC3).
826 845
827=item L<Net::XMPP2> 846=item L<Net::XMPP2>
828 847
829AnyEvent based XMPP (Jabber protocol) module family. 848AnyEvent based XMPP (Jabber protocol) module family.
830 849
854no warnings; 873no warnings;
855use strict qw(vars subs); 874use strict qw(vars subs);
856 875
857use Carp; 876use Carp;
858 877
859our $VERSION = 4.233; 878our $VERSION = 4.35;
860our $MODEL; 879our $MODEL;
861 880
862our $AUTOLOAD; 881our $AUTOLOAD;
863our @ISA; 882our @ISA;
864 883
997# to support binding more than one watcher per filehandle (they usually 1016# to support binding more than one watcher per filehandle (they usually
998# allow only one watcher per fd, so we dup it to get a different one). 1017# allow only one watcher per fd, so we dup it to get a different one).
999sub _dupfh($$$$) { 1018sub _dupfh($$$$) {
1000 my ($poll, $fh, $r, $w) = @_; 1019 my ($poll, $fh, $r, $w) = @_;
1001 1020
1002 require Fcntl;
1003
1004 # cygwin requires the fh mode to be matching, unix doesn't 1021 # cygwin requires the fh mode to be matching, unix doesn't
1005 my ($rw, $mode) = $poll eq "r" ? ($r, "<") 1022 my ($rw, $mode) = $poll eq "r" ? ($r, "<")
1006 : $poll eq "w" ? ($w, ">") 1023 : $poll eq "w" ? ($w, ">")
1007 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'"; 1024 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1008 1025
1021BEGIN { 1038BEGIN {
1022 if (eval "use Time::HiRes (); time (); 1") { 1039 if (eval "use Time::HiRes (); time (); 1") {
1023 *_time = \&Time::HiRes::time; 1040 *_time = \&Time::HiRes::time;
1024 # if (eval "use POSIX (); (POSIX::times())... 1041 # if (eval "use POSIX (); (POSIX::times())...
1025 } else { 1042 } else {
1026 *_time = \&CORE::time; # epic fail 1043 *_time = sub { time }; # epic fail
1027 } 1044 }
1028} 1045}
1029 1046
1030sub time { _time } 1047sub time { _time }
1031sub now { _time } 1048sub now { _time }
1036 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: 1053 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
1037} 1054}
1038 1055
1039# default implementation for ->signal 1056# default implementation for ->signal
1040 1057
1041our %SIG_CB; 1058our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1059
1060sub _signal_exec {
1061 sysread $SIGPIPE_R, my $dummy, 4;
1062
1063 while (%SIG_EV) {
1064 for (keys %SIG_EV) {
1065 delete $SIG_EV{$_};
1066 $_->() for values %{ $SIG_CB{$_} || {} };
1067 }
1068 }
1069}
1042 1070
1043sub signal { 1071sub signal {
1044 my (undef, %arg) = @_; 1072 my (undef, %arg) = @_;
1045 1073
1074 unless ($SIGPIPE_R) {
1075 if (AnyEvent::WIN32) {
1076 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1077 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1078 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1079 } else {
1080 pipe $SIGPIPE_R, $SIGPIPE_W;
1081 require Fcntl;
1082 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1083 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1084 }
1085
1086 $SIGPIPE_R
1087 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1088
1089 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1090 }
1091
1046 my $signal = uc $arg{signal} 1092 my $signal = uc $arg{signal}
1047 or Carp::croak "required option 'signal' is missing"; 1093 or Carp::croak "required option 'signal' is missing";
1048 1094
1049 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1095 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1050 $SIG{$signal} ||= sub { 1096 $SIG{$signal} ||= sub {
1051 $_->() for values %{ $SIG_CB{$signal} || {} }; 1097 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1098 undef $SIG_EV{$signal};
1052 }; 1099 };
1053 1100
1054 bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" 1101 bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
1055} 1102}
1056 1103
1256used, and preference will be given to protocols mentioned earlier in the 1303used, and preference will be given to protocols mentioned earlier in the
1257list. 1304list.
1258 1305
1259This variable can effectively be used for denial-of-service attacks 1306This variable can effectively be used for denial-of-service attacks
1260against local programs (e.g. when setuid), although the impact is likely 1307against local programs (e.g. when setuid), although the impact is likely
1261small, as the program has to handle connection errors already- 1308small, as the program has to handle conenction and other failures anyways.
1262 1309
1263Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6, 1310Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1264but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> 1311but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1265- only support IPv4, never try to resolve or contact IPv6 1312- only support IPv4, never try to resolve or contact IPv6
1266addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or 1313addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1526watcher. 1573watcher.
1527 1574
1528=head3 Results 1575=head3 Results
1529 1576
1530 name watchers bytes create invoke destroy comment 1577 name watchers bytes create invoke destroy comment
1531 EV/EV 400000 244 0.56 0.46 0.31 EV native interface 1578 EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1532 EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers 1579 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1533 CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal 1580 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1534 Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation 1581 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1535 Event/Event 16000 516 31.88 31.30 0.85 Event native interface 1582 Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1536 Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers 1583 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1537 Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour 1584 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1538 Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers 1585 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1539 POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event 1586 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1540 POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select 1587 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1541 1588
1542=head3 Discussion 1589=head3 Discussion
1543 1590
1544The benchmark does I<not> measure scalability of the event loop very 1591The benchmark does I<not> measure scalability of the event loop very
1545well. For example, a select-based event loop (such as the pure perl one) 1592well. For example, a select-based event loop (such as the pure perl one)
1747watchers, as the management overhead dominates. 1794watchers, as the management overhead dominates.
1748 1795
1749=back 1796=back
1750 1797
1751 1798
1799=head1 SIGNALS
1800
1801AnyEvent currently installs handlers for these signals:
1802
1803=over 4
1804
1805=item SIGCHLD
1806
1807A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1808emulation for event loops that do not support them natively. Also, some
1809event loops install a similar handler.
1810
1811=item SIGPIPE
1812
1813A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1814when AnyEvent gets loaded.
1815
1816The rationale for this is that AnyEvent users usually do not really depend
1817on SIGPIPE delivery (which is purely an optimisation for shell use, or
1818badly-written programs), but C<SIGPIPE> can cause spurious and rare
1819program exits as a lot of people do not expect C<SIGPIPE> when writing to
1820some random socket.
1821
1822The rationale for installing a no-op handler as opposed to ignoring it is
1823that this way, the handler will be restored to defaults on exec.
1824
1825Feel free to install your own handler, or reset it to defaults.
1826
1827=back
1828
1829=cut
1830
1831$SIG{PIPE} = sub { }
1832 unless defined $SIG{PIPE};
1833
1834
1752=head1 FORK 1835=head1 FORK
1753 1836
1754Most event libraries are not fork-safe. The ones who are usually are 1837Most event libraries are not fork-safe. The ones who are usually are
1755because they rely on inefficient but fork-safe C<select> or C<poll> 1838because they rely on inefficient but fork-safe C<select> or C<poll>
1756calls. Only L<EV> is fully fork-aware. 1839calls. Only L<EV> is fully fork-aware.
1784=head1 BUGS 1867=head1 BUGS
1785 1868
1786Perl 5.8 has numerous memleaks that sometimes hit this module and are hard 1869Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1787to work around. If you suffer from memleaks, first upgrade to Perl 5.10 1870to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1788and check wether the leaks still show up. (Perl 5.10.0 has other annoying 1871and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1789mamleaks, such as leaking on C<map> and C<grep> but it is usually not as 1872memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1790pronounced). 1873pronounced).
1791 1874
1792 1875
1793=head1 SEE ALSO 1876=head1 SEE ALSO
1794 1877

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