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Revision 1.150 by root, Sat May 31 13:06:45 2008 UTC vs.
Revision 1.164 by root, Tue Jul 8 19:50:25 2008 UTC

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138Many watchers either are used with "recursion" (repeating timers for 138Many watchers either are used with "recursion" (repeating timers for
139example), or need to refer to their watcher object in other ways. 139example), or need to refer to their watcher object in other ways.
140 140
141An any way to achieve that is this pattern: 141An any way to achieve that is this pattern:
142 142
143 my $w; $w = AnyEvent->type (arg => value ..., cb => sub { 143 my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
144 # you can use $w here, for example to undef it 144 # you can use $w here, for example to undef it
145 undef $w; 145 undef $w;
146 }); 146 });
147 147
148Note that C<my $w; $w => combination. This is necessary because in Perl, 148Note that C<my $w; $w => combination. This is necessary because in Perl,
149my variables are only visible after the statement in which they are 149my variables are only visible after the statement in which they are
150declared. 150declared.
151 151
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170 170
171Some event loops issue spurious readyness notifications, so you should 171Some event loops issue spurious readyness notifications, so you should
172always use non-blocking calls when reading/writing from/to your file 172always use non-blocking calls when reading/writing from/to your file
173handles. 173handles.
174 174
175Example:
176
177 # wait for readability of STDIN, then read a line and disable the watcher 175Example: wait for readability of STDIN, then read a line and disable the
176watcher.
177
178 my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { 178 my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
179 chomp (my $input = <STDIN>); 179 chomp (my $input = <STDIN>);
180 warn "read: $input\n"; 180 warn "read: $input\n";
181 undef $w; 181 undef $w;
182 }); 182 });
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192 192
193Although the callback might get passed parameters, their value and 193Although the callback might get passed parameters, their value and
194presence is undefined and you cannot rely on them. Portable AnyEvent 194presence is undefined and you cannot rely on them. Portable AnyEvent
195callbacks cannot use arguments passed to time watcher callbacks. 195callbacks cannot use arguments passed to time watcher callbacks.
196 196
197The timer callback will be invoked at most once: if you want a repeating 197The callback will normally be invoked once only. If you specify another
198timer you have to create a new watcher (this is a limitation by both Tk 198parameter, C<interval>, as a positive number, then the callback will be
199and Glib). 199invoked regularly at that interval (in fractional seconds) after the first
200invocation.
200 201
201Example: 202The callback will be rescheduled before invoking the callback, but no
203attempt is done to avoid timer drift in most backends, so the interval is
204only approximate.
202 205
203 # fire an event after 7.7 seconds 206Example: fire an event after 7.7 seconds.
207
204 my $w = AnyEvent->timer (after => 7.7, cb => sub { 208 my $w = AnyEvent->timer (after => 7.7, cb => sub {
205 warn "timeout\n"; 209 warn "timeout\n";
206 }); 210 });
207 211
208 # to cancel the timer: 212 # to cancel the timer:
209 undef $w; 213 undef $w;
210 214
211Example 2:
212
213 # fire an event after 0.5 seconds, then roughly every second 215Example 2: fire an event after 0.5 seconds, then roughly every second.
214 my $w;
215 216
216 my $cb = sub {
217 # cancel the old timer while creating a new one
218 $w = AnyEvent->timer (after => 1, cb => $cb); 217 my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
218 warn "timeout\n";
219 }; 219 };
220
221 # start the "loop" by creating the first watcher
222 $w = AnyEvent->timer (after => 0.5, cb => $cb);
223 220
224=head3 TIMING ISSUES 221=head3 TIMING ISSUES
225 222
226There are two ways to handle timers: based on real time (relative, "fire 223There are two ways to handle timers: based on real time (relative, "fire
227in 10 seconds") and based on wallclock time (absolute, "fire at 12 224in 10 seconds") and based on wallclock time (absolute, "fire at 12
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352AnyEvent program, you I<have> to create at least one watcher before you 349AnyEvent program, you I<have> to create at least one watcher before you
353C<fork> the child (alternatively, you can call C<AnyEvent::detect>). 350C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
354 351
355Example: fork a process and wait for it 352Example: fork a process and wait for it
356 353
357 my $done = AnyEvent->condvar; 354 my $done = AnyEvent->condvar;
358 355
359 my $pid = fork or exit 5; 356 my $pid = fork or exit 5;
360 357
361 my $w = AnyEvent->child ( 358 my $w = AnyEvent->child (
362 pid => $pid, 359 pid => $pid,
363 cb => sub { 360 cb => sub {
364 my ($pid, $status) = @_; 361 my ($pid, $status) = @_;
365 warn "pid $pid exited with status $status"; 362 warn "pid $pid exited with status $status";
366 $done->send; 363 $done->send;
367 }, 364 },
368 ); 365 );
369 366
370 # do something else, then wait for process exit 367 # do something else, then wait for process exit
371 $done->recv; 368 $done->recv;
372 369
373=head2 CONDITION VARIABLES 370=head2 CONDITION VARIABLES
374 371
375If you are familiar with some event loops you will know that all of them 372If you are familiar with some event loops you will know that all of them
376require you to run some blocking "loop", "run" or similar function that 373require you to run some blocking "loop", "run" or similar function that
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738=item L<AnyEvent::Util> 735=item L<AnyEvent::Util>
739 736
740Contains various utility functions that replace often-used but blocking 737Contains various utility functions that replace often-used but blocking
741functions such as C<inet_aton> by event-/callback-based versions. 738functions such as C<inet_aton> by event-/callback-based versions.
742 739
743=item L<AnyEvent::Handle>
744
745Provide read and write buffers and manages watchers for reads and writes.
746
747=item L<AnyEvent::Socket> 740=item L<AnyEvent::Socket>
748 741
749Provides various utility functions for (internet protocol) sockets, 742Provides various utility functions for (internet protocol) sockets,
750addresses and name resolution. Also functions to create non-blocking tcp 743addresses and name resolution. Also functions to create non-blocking tcp
751connections or tcp servers, with IPv6 and SRV record support and more. 744connections or tcp servers, with IPv6 and SRV record support and more.
752 745
746=item L<AnyEvent::Handle>
747
748Provide read and write buffers, manages watchers for reads and writes,
749supports raw and formatted I/O, I/O queued and fully transparent and
750non-blocking SSL/TLS.
751
753=item L<AnyEvent::DNS> 752=item L<AnyEvent::DNS>
754 753
755Provides rich asynchronous DNS resolver capabilities. 754Provides rich asynchronous DNS resolver capabilities.
756 755
756=item L<AnyEvent::HTTP>
757
758A simple-to-use HTTP library that is capable of making a lot of concurrent
759HTTP requests.
760
757=item L<AnyEvent::HTTPD> 761=item L<AnyEvent::HTTPD>
758 762
759Provides a simple web application server framework. 763Provides a simple web application server framework.
760 764
761=item L<AnyEvent::FastPing> 765=item L<AnyEvent::FastPing>
762 766
763The fastest ping in the west. 767The fastest ping in the west.
768
769=item L<AnyEvent::DBI>
770
771Executes L<DBI> requests asynchronously in a proxy process.
772
773=item L<AnyEvent::AIO>
774
775Truly asynchronous I/O, should be in the toolbox of every event
776programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
777together.
778
779=item L<AnyEvent::BDB>
780
781Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
782L<BDB> and AnyEvent together.
783
784=item L<AnyEvent::GPSD>
785
786A non-blocking interface to gpsd, a daemon delivering GPS information.
787
788=item L<AnyEvent::IGS>
789
790A non-blocking interface to the Internet Go Server protocol (used by
791L<App::IGS>).
764 792
765=item L<Net::IRC3> 793=item L<Net::IRC3>
766 794
767AnyEvent based IRC client module family. 795AnyEvent based IRC client module family.
768 796
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781 809
782=item L<Coro> 810=item L<Coro>
783 811
784Has special support for AnyEvent via L<Coro::AnyEvent>. 812Has special support for AnyEvent via L<Coro::AnyEvent>.
785 813
786=item L<AnyEvent::AIO>, L<IO::AIO>
787
788Truly asynchronous I/O, should be in the toolbox of every event
789programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
790together.
791
792=item L<AnyEvent::BDB>, L<BDB>
793
794Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
795IO::AIO and AnyEvent together.
796
797=item L<IO::Lambda> 814=item L<IO::Lambda>
798 815
799The lambda approach to I/O - don't ask, look there. Can use AnyEvent. 816The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
800 817
801=back 818=back
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807no warnings; 824no warnings;
808use strict; 825use strict;
809 826
810use Carp; 827use Carp;
811 828
812our $VERSION = 4.11; 829our $VERSION = 4.2;
813our $MODEL; 830our $MODEL;
814 831
815our $AUTOLOAD; 832our $AUTOLOAD;
816our @ISA; 833our @ISA;
817 834
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979sub AnyEvent::Base::Signal::DESTROY { 996sub AnyEvent::Base::Signal::DESTROY {
980 my ($signal, $cb) = @{$_[0]}; 997 my ($signal, $cb) = @{$_[0]};
981 998
982 delete $SIG_CB{$signal}{$cb}; 999 delete $SIG_CB{$signal}{$cb};
983 1000
984 $SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} }; 1001 delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
985} 1002}
986 1003
987# default implementation for ->child 1004# default implementation for ->child
988 1005
989our %PID_CB; 1006our %PID_CB;
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1173This functionality might change in future versions. 1190This functionality might change in future versions.
1174 1191
1175For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you 1192For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1176could start your program like this: 1193could start your program like this:
1177 1194
1178 PERL_ANYEVENT_MODEL=Perl perl ... 1195 PERL_ANYEVENT_MODEL=Perl perl ...
1179 1196
1180=item C<PERL_ANYEVENT_PROTOCOLS> 1197=item C<PERL_ANYEVENT_PROTOCOLS>
1181 1198
1182Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences 1199Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1183for IPv4 or IPv6. The default is unspecified (and might change, or be the result 1200for IPv4 or IPv6. The default is unspecified (and might change, or be the result
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1658specified in the variable. 1675specified in the variable.
1659 1676
1660You can make AnyEvent completely ignore this variable by deleting it 1677You can make AnyEvent completely ignore this variable by deleting it
1661before the first watcher gets created, e.g. with a C<BEGIN> block: 1678before the first watcher gets created, e.g. with a C<BEGIN> block:
1662 1679
1663 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } 1680 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1664 1681
1665 use AnyEvent; 1682 use AnyEvent;
1666 1683
1667Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can 1684Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1668be used to probe what backend is used and gain other information (which is 1685be used to probe what backend is used and gain other information (which is
1669probably even less useful to an attacker than PERL_ANYEVENT_MODEL). 1686probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
1687
1688
1689=head1 BUGS
1690
1691Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1692to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1693and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1694mamleaks, such as leaking on C<map> and C<grep> but it is usually not as
1695pronounced).
1670 1696
1671 1697
1672=head1 SEE ALSO 1698=head1 SEE ALSO
1673 1699
1674Utility functions: L<AnyEvent::Util>. 1700Utility functions: L<AnyEvent::Util>.
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1691Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 1717Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1692 1718
1693 1719
1694=head1 AUTHOR 1720=head1 AUTHOR
1695 1721
1696 Marc Lehmann <schmorp@schmorp.de> 1722 Marc Lehmann <schmorp@schmorp.de>
1697 http://home.schmorp.de/ 1723 http://home.schmorp.de/
1698 1724
1699=cut 1725=cut
1700 1726
17011 17271
1702 1728

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