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Revision 1.177 by root, Thu Aug 21 18:45:16 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
850=cut 869=cut
851 870
852package AnyEvent; 871package AnyEvent;
853 872
854no warnings; 873no warnings;
855use strict; 874use strict qw(vars subs);
856 875
857use Carp; 876use Carp;
858 877
859our $VERSION = 4.232; 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
1016 1033
1017package AnyEvent::Base; 1034package AnyEvent::Base;
1018 1035
1019# default implementation for now and time 1036# default implementation for now and time
1020 1037
1021use Time::HiRes (); 1038BEGIN {
1039 if (eval "use Time::HiRes (); time (); 1") {
1040 *_time = \&Time::HiRes::time;
1041 # if (eval "use POSIX (); (POSIX::times())...
1042 } else {
1043 *_time = sub { time }; # epic fail
1044 }
1045}
1022 1046
1023sub time { Time::HiRes::time } 1047sub time { _time }
1024sub now { Time::HiRes::time } 1048sub now { _time }
1025 1049
1026# default implementation for ->condvar 1050# default implementation for ->condvar
1027 1051
1028sub condvar { 1052sub condvar {
1029 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: 1053 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
1030} 1054}
1031 1055
1032# default implementation for ->signal 1056# default implementation for ->signal
1033 1057
1034our %SIG_CB; 1058our ($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}
1035 1070
1036sub signal { 1071sub signal {
1037 my (undef, %arg) = @_; 1072 my (undef, %arg) = @_;
1038 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
1039 my $signal = uc $arg{signal} 1092 my $signal = uc $arg{signal}
1040 or Carp::croak "required option 'signal' is missing"; 1093 or Carp::croak "required option 'signal' is missing";
1041 1094
1042 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1095 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1043 $SIG{$signal} ||= sub { 1096 $SIG{$signal} ||= sub {
1044 $_->() for values %{ $SIG_CB{$signal} || {} }; 1097 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1098 undef $SIG_EV{$signal};
1045 }; 1099 };
1046 1100
1047 bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" 1101 bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
1048} 1102}
1049 1103
1168 1222
1169# undocumented/compatibility with pre-3.4 1223# undocumented/compatibility with pre-3.4
1170*broadcast = \&send; 1224*broadcast = \&send;
1171*wait = \&_wait; 1225*wait = \&_wait;
1172 1226
1227=head1 ERROR AND EXCEPTION HANDLING
1228
1229In general, AnyEvent does not do any error handling - it relies on the
1230caller to do that if required. The L<AnyEvent::Strict> module (see also
1231the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
1232checking of all AnyEvent methods, however, which is highly useful during
1233development.
1234
1235As for exception handling (i.e. runtime errors and exceptions thrown while
1236executing a callback), this is not only highly event-loop specific, but
1237also not in any way wrapped by this module, as this is the job of the main
1238program.
1239
1240The pure perl event loop simply re-throws the exception (usually
1241within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
1242$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1243so on.
1244
1245=head1 ENVIRONMENT VARIABLES
1246
1247The following environment variables are used by this module or its
1248submodules:
1249
1250=over 4
1251
1252=item C<PERL_ANYEVENT_VERBOSE>
1253
1254By default, AnyEvent will be completely silent except in fatal
1255conditions. You can set this environment variable to make AnyEvent more
1256talkative.
1257
1258When set to C<1> or higher, causes AnyEvent to warn about unexpected
1259conditions, such as not being able to load the event model specified by
1260C<PERL_ANYEVENT_MODEL>.
1261
1262When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1263model it chooses.
1264
1265=item C<PERL_ANYEVENT_STRICT>
1266
1267AnyEvent does not do much argument checking by default, as thorough
1268argument checking is very costly. Setting this variable to a true value
1269will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1270check the arguments passed to most method calls. If it finds any problems
1271it will croak.
1272
1273In other words, enables "strict" mode.
1274
1275Unlike C<use strict>, it is definitely recommended ot keep it off in
1276production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
1277developing programs can be very useful, however.
1278
1279=item C<PERL_ANYEVENT_MODEL>
1280
1281This can be used to specify the event model to be used by AnyEvent, before
1282auto detection and -probing kicks in. It must be a string consisting
1283entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1284and the resulting module name is loaded and if the load was successful,
1285used as event model. If it fails to load AnyEvent will proceed with
1286auto detection and -probing.
1287
1288This functionality might change in future versions.
1289
1290For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1291could start your program like this:
1292
1293 PERL_ANYEVENT_MODEL=Perl perl ...
1294
1295=item C<PERL_ANYEVENT_PROTOCOLS>
1296
1297Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1298for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1299of auto probing).
1300
1301Must be set to a comma-separated list of protocols or address families,
1302current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1303used, and preference will be given to protocols mentioned earlier in the
1304list.
1305
1306This variable can effectively be used for denial-of-service attacks
1307against local programs (e.g. when setuid), although the impact is likely
1308small, as the program has to handle conenction and other failures anyways.
1309
1310Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1311but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1312- only support IPv4, never try to resolve or contact IPv6
1313addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1314IPv6, but prefer IPv6 over IPv4.
1315
1316=item C<PERL_ANYEVENT_EDNS0>
1317
1318Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1319for DNS. This extension is generally useful to reduce DNS traffic, but
1320some (broken) firewalls drop such DNS packets, which is why it is off by
1321default.
1322
1323Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1324EDNS0 in its DNS requests.
1325
1326=item C<PERL_ANYEVENT_MAX_FORKS>
1327
1328The maximum number of child processes that C<AnyEvent::Util::fork_call>
1329will create in parallel.
1330
1331=back
1332
1173=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1333=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1174 1334
1175This is an advanced topic that you do not normally need to use AnyEvent in 1335This is an advanced topic that you do not normally need to use AnyEvent in
1176a module. This section is only of use to event loop authors who want to 1336a module. This section is only of use to event loop authors who want to
1177provide AnyEvent compatibility. 1337provide AnyEvent compatibility.
1210 1370
1211I<rxvt-unicode> also cheats a bit by not providing blocking access to 1371I<rxvt-unicode> also cheats a bit by not providing blocking access to
1212condition variables: code blocking while waiting for a condition will 1372condition variables: code blocking while waiting for a condition will
1213C<die>. This still works with most modules/usages, and blocking calls must 1373C<die>. This still works with most modules/usages, and blocking calls must
1214not be done in an interactive application, so it makes sense. 1374not be done in an interactive application, so it makes sense.
1215
1216=head1 ENVIRONMENT VARIABLES
1217
1218The following environment variables are used by this module:
1219
1220=over 4
1221
1222=item C<PERL_ANYEVENT_VERBOSE>
1223
1224By default, AnyEvent will be completely silent except in fatal
1225conditions. You can set this environment variable to make AnyEvent more
1226talkative.
1227
1228When set to C<1> or higher, causes AnyEvent to warn about unexpected
1229conditions, such as not being able to load the event model specified by
1230C<PERL_ANYEVENT_MODEL>.
1231
1232When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1233model it chooses.
1234
1235=item C<PERL_ANYEVENT_STRICT>
1236
1237AnyEvent does not do much argument checking by default, as thorough
1238argument checking is very costly. Setting this variable to a true value
1239will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1240check the arguments passed to most method calls. If it finds any problems
1241it will croak.
1242
1243In other words, enables "strict" mode.
1244
1245Unlike C<use strict> it is definitely recommended ot keep it off in
1246production.
1247
1248=item C<PERL_ANYEVENT_MODEL>
1249
1250This can be used to specify the event model to be used by AnyEvent, before
1251auto detection and -probing kicks in. It must be a string consisting
1252entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1253and the resulting module name is loaded and if the load was successful,
1254used as event model. If it fails to load AnyEvent will proceed with
1255auto detection and -probing.
1256
1257This functionality might change in future versions.
1258
1259For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1260could start your program like this:
1261
1262 PERL_ANYEVENT_MODEL=Perl perl ...
1263
1264=item C<PERL_ANYEVENT_PROTOCOLS>
1265
1266Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1267for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1268of auto probing).
1269
1270Must be set to a comma-separated list of protocols or address families,
1271current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1272used, and preference will be given to protocols mentioned earlier in the
1273list.
1274
1275This variable can effectively be used for denial-of-service attacks
1276against local programs (e.g. when setuid), although the impact is likely
1277small, as the program has to handle connection errors already-
1278
1279Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1280but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1281- only support IPv4, never try to resolve or contact IPv6
1282addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1283IPv6, but prefer IPv6 over IPv4.
1284
1285=item C<PERL_ANYEVENT_EDNS0>
1286
1287Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1288for DNS. This extension is generally useful to reduce DNS traffic, but
1289some (broken) firewalls drop such DNS packets, which is why it is off by
1290default.
1291
1292Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1293EDNS0 in its DNS requests.
1294
1295=item C<PERL_ANYEVENT_MAX_FORKS>
1296
1297The maximum number of child processes that C<AnyEvent::Util::fork_call>
1298will create in parallel.
1299
1300=back
1301 1375
1302=head1 EXAMPLE PROGRAM 1376=head1 EXAMPLE PROGRAM
1303 1377
1304The following program uses an I/O watcher to read data from STDIN, a timer 1378The following program uses an I/O watcher to read data from STDIN, a timer
1305to display a message once per second, and a condition variable to quit the 1379to display a message once per second, and a condition variable to quit the
1499watcher. 1573watcher.
1500 1574
1501=head3 Results 1575=head3 Results
1502 1576
1503 name watchers bytes create invoke destroy comment 1577 name watchers bytes create invoke destroy comment
1504 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
1505 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
1506 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
1507 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
1508 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
1509 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
1510 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
1511 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
1512 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
1513 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
1514 1588
1515=head3 Discussion 1589=head3 Discussion
1516 1590
1517The benchmark does I<not> measure scalability of the event loop very 1591The benchmark does I<not> measure scalability of the event loop very
1518well. 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)
1720watchers, as the management overhead dominates. 1794watchers, as the management overhead dominates.
1721 1795
1722=back 1796=back
1723 1797
1724 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
1725=head1 FORK 1835=head1 FORK
1726 1836
1727Most 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
1728because 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>
1729calls. Only L<EV> is fully fork-aware. 1839calls. Only L<EV> is fully fork-aware.
1757=head1 BUGS 1867=head1 BUGS
1758 1868
1759Perl 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
1760to 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
1761and 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
1762mamleaks, 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
1763pronounced). 1873pronounced).
1764 1874
1765 1875
1766=head1 SEE ALSO 1876=head1 SEE ALSO
1767 1877

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