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Revision 1.136 by root, Sun May 25 23:52:02 2008 UTC vs.
Revision 1.145 by root, Thu May 29 03:45:37 2008 UTC

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48isn't itself. What's worse, all the potential users of your module are 48isn't itself. What's worse, all the potential users of your module are
49I<also> forced to use the same event loop you use. 49I<also> forced to use the same event loop you use.
50 50
51AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works 51AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52fine. AnyEvent + Tk works fine etc. etc. but none of these work together 52fine. AnyEvent + Tk works fine etc. etc. but none of these work together
53with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if 53with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
54your module uses one of those, every user of your module has to use it, 54your module uses one of those, every user of your module has to use it,
55too. But if your module uses AnyEvent, it works transparently with all 55too. But if your module uses AnyEvent, it works transparently with all
56event models it supports (including stuff like POE and IO::Async, as long 56event models it supports (including stuff like POE and IO::Async, as long
57as those use one of the supported event loops. It is trivial to add new 57as those use one of the supported event loops. It is trivial to add new
58event loops to AnyEvent, too, so it is future-proof). 58event loops to AnyEvent, too, so it is future-proof).
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62modules, you get an enormous amount of code and strict rules you have to 62modules, you get an enormous amount of code and strict rules you have to
63follow. AnyEvent, on the other hand, is lean and up to the point, by only 63follow. AnyEvent, on the other hand, is lean and up to the point, by only
64offering the functionality that is necessary, in as thin as a wrapper as 64offering the functionality that is necessary, in as thin as a wrapper as
65technically possible. 65technically possible.
66 66
67Of course, AnyEvent comes with a big (and fully optional!) toolbox
68of useful functionality, such as an asynchronous DNS resolver, 100%
69non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
70such as Windows) and lots of real-world knowledge and workarounds for
71platform bugs and differences.
72
67Of course, if you want lots of policy (this can arguably be somewhat 73Now, if you I<do want> lots of policy (this can arguably be somewhat
68useful) and you want to force your users to use the one and only event 74useful) and you want to force your users to use the one and only event
69model, you should I<not> use this module. 75model, you should I<not> use this module.
70 76
71=head1 DESCRIPTION 77=head1 DESCRIPTION
72 78
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102starts using it, all bets are off. Maybe you should tell their authors to 108starts using it, all bets are off. Maybe you should tell their authors to
103use AnyEvent so their modules work together with others seamlessly... 109use AnyEvent so their modules work together with others seamlessly...
104 110
105The pure-perl implementation of AnyEvent is called 111The pure-perl implementation of AnyEvent is called
106C<AnyEvent::Impl::Perl>. Like other event modules you can load it 112C<AnyEvent::Impl::Perl>. Like other event modules you can load it
107explicitly. 113explicitly and enjoy the high availability of that event loop :)
108 114
109=head1 WATCHERS 115=head1 WATCHERS
110 116
111AnyEvent has the central concept of a I<watcher>, which is an object that 117AnyEvent has the central concept of a I<watcher>, which is an object that
112stores relevant data for each kind of event you are waiting for, such as 118stores relevant data for each kind of event you are waiting for, such as
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226on true relative time) and absolute (ev_periodic, based on wallclock time) 232on true relative time) and absolute (ev_periodic, based on wallclock time)
227timers. 233timers.
228 234
229AnyEvent always prefers relative timers, if available, matching the 235AnyEvent always prefers relative timers, if available, matching the
230AnyEvent API. 236AnyEvent API.
237
238AnyEvent has two additional methods that return the "current time":
239
240=over 4
241
242=item AnyEvent->time
243
244This returns the "current wallclock time" as a fractional number of
245seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
246return, and the result is guaranteed to be compatible with those).
247
248It progresses independently of any event loop processing, i.e. each call
249will check the system clock, which usually gets updated frequently.
250
251=item AnyEvent->now
252
253This also returns the "current wallclock time", but unlike C<time>, above,
254this value might change only once per event loop iteration, depending on
255the event loop (most return the same time as C<time>, above). This is the
256time that AnyEvent's timers get scheduled against.
257
258I<In almost all cases (in all cases if you don't care), this is the
259function to call when you want to know the current time.>
260
261This function is also often faster then C<< AnyEvent->time >>, and
262thus the preferred method if you want some timestamp (for example,
263L<AnyEvent::Handle> uses this to update it's activity timeouts).
264
265The rest of this section is only of relevance if you try to be very exact
266with your timing, you can skip it without bad conscience.
267
268For a practical example of when these times differ, consider L<Event::Lib>
269and L<EV> and the following set-up:
270
271The event loop is running and has just invoked one of your callback at
272time=500 (assume no other callbacks delay processing). In your callback,
273you wait a second by executing C<sleep 1> (blocking the process for a
274second) and then (at time=501) you create a relative timer that fires
275after three seconds.
276
277With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
278both return C<501>, because that is the current time, and the timer will
279be scheduled to fire at time=504 (C<501> + C<3>).
280
281With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
282time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
283last event processing phase started. With L<EV>, your timer gets scheduled
284to run at time=503 (C<500> + C<3>).
285
286In one sense, L<Event::Lib> is more exact, as it uses the current time
287regardless of any delays introduced by event processing. However, most
288callbacks do not expect large delays in processing, so this causes a
289higher drift (and a lot more system calls to get the current time).
290
291In another sense, L<EV> is more exact, as your timer will be scheduled at
292the same time, regardless of how long event processing actually took.
293
294In either case, if you care (and in most cases, you don't), then you
295can get whatever behaviour you want with any event loop, by taking the
296difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
297account.
298
299=back
231 300
232=head2 SIGNAL WATCHERS 301=head2 SIGNAL WATCHERS
233 302
234You can watch for signals using a signal watcher, C<signal> is the signal 303You can watch for signals using a signal watcher, C<signal> is the signal
235I<name> without any C<SIG> prefix, C<cb> is the Perl callback to 304I<name> without any C<SIG> prefix, C<cb> is the Perl callback to
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731no warnings; 800no warnings;
732use strict; 801use strict;
733 802
734use Carp; 803use Carp;
735 804
736our $VERSION = '4.03'; 805our $VERSION = '4.1';
737our $MODEL; 806our $MODEL;
738 807
739our $AUTOLOAD; 808our $AUTOLOAD;
740our @ISA; 809our @ISA;
741 810
742our @REGISTRY; 811our @REGISTRY;
812
813our $WIN32;
814
815BEGIN {
816 my $win32 = ! ! ($^O =~ /mswin32/i);
817 eval "sub WIN32(){ $win32 }";
818}
743 819
744our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 820our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
745 821
746our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 822our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
747 823
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766 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 842 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
767 [Wx:: => AnyEvent::Impl::POE::], 843 [Wx:: => AnyEvent::Impl::POE::],
768 [Prima:: => AnyEvent::Impl::POE::], 844 [Prima:: => AnyEvent::Impl::POE::],
769); 845);
770 846
771our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY); 847our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
772 848
773our @post_detect; 849our @post_detect;
774 850
775sub post_detect(&) { 851sub post_detect(&) {
776 my ($cb) = @_; 852 my ($cb) = @_;
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793} 869}
794 870
795sub detect() { 871sub detect() {
796 unless ($MODEL) { 872 unless ($MODEL) {
797 no strict 'refs'; 873 no strict 'refs';
874 local $SIG{__DIE__};
798 875
799 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 876 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
800 my $model = "AnyEvent::Impl::$1"; 877 my $model = "AnyEvent::Impl::$1";
801 if (eval "require $model") { 878 if (eval "require $model") {
802 $MODEL = $model; 879 $MODEL = $model;
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859 $class->$func (@_); 936 $class->$func (@_);
860} 937}
861 938
862package AnyEvent::Base; 939package AnyEvent::Base;
863 940
941# default implementation for now and time
942
943use Time::HiRes ();
944
945sub time { Time::HiRes::time }
946sub now { Time::HiRes::time }
947
864# default implementation for ->condvar 948# default implementation for ->condvar
865 949
866sub condvar { 950sub condvar {
867 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: 951 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
868} 952}
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925 or Carp::croak "required option 'pid' is missing"; 1009 or Carp::croak "required option 'pid' is missing";
926 1010
927 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1011 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
928 1012
929 unless ($WNOHANG) { 1013 unless ($WNOHANG) {
930 $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1; 1014 $WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
931 } 1015 }
932 1016
933 unless ($CHLD_W) { 1017 unless ($CHLD_W) {
934 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1018 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
935 # child could be a zombie already, so make at least one round 1019 # child could be a zombie already, so make at least one round
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1114some (broken) firewalls drop such DNS packets, which is why it is off by 1198some (broken) firewalls drop such DNS packets, which is why it is off by
1115default. 1199default.
1116 1200
1117Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce 1201Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1118EDNS0 in its DNS requests. 1202EDNS0 in its DNS requests.
1203
1204=item C<PERL_ANYEVENT_MAX_FORKS>
1205
1206The maximum number of child processes that C<AnyEvent::Util::fork_call>
1207will create in parallel.
1119 1208
1120=back 1209=back
1121 1210
1122=head1 EXAMPLE PROGRAM 1211=head1 EXAMPLE PROGRAM
1123 1212

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