[ViewVC] Diff of: cvs/AnyEvent/lib/AnyEvent.pm

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.140 by root, Mon May 26 06:18:53 2008 UTC vs.
Revision 1.143 by root, Wed May 28 23:57:38 2008 UTC

 isn't itself. What's worse, all the potential users of your module are
 I<also> forced to use the same event loop you use.
 AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
 fine. AnyEvent + Tk works fine etc. etc. but none of these work together
-with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if
+with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
 your module uses one of those, every user of your module has to use it,
 too. But if your module uses AnyEvent, it works transparently with all
 event models it supports (including stuff like POE and IO::Async, as long
 as those use one of the supported event loops. It is trivial to add new
 event loops to AnyEvent, too, so it is future-proof).
 modules, you get an enormous amount of code and strict rules you have to
 follow. AnyEvent, on the other hand, is lean and up to the point, by only
 offering the functionality that is necessary, in as thin as a wrapper as
 technically possible.
+Of course, AnyEvent comes with a big (and fully optional!) toolbox
+of useful functionality, such as an asynchronous DNS resolver, 100%
+non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
+such as Windows) and lots of real-world knowledge and workarounds for
+platform bugs and differences.
-Of course, if you want lots of policy (this can arguably be somewhat
+Now, if you I<do want> lots of policy (this can arguably be somewhat
 useful) and you want to force your users to use the one and only event
 model, you should I<not> use this module.
 =head1 DESCRIPTION
 starts using it, all bets are off. Maybe you should tell their authors to
 use AnyEvent so their modules work together with others seamlessly...
 The pure-perl implementation of AnyEvent is called
 C<AnyEvent::Impl::Perl>. Like other event modules you can load it
-explicitly.
+explicitly and enjoy the high availability of that event loop :)
 =head1 WATCHERS
 AnyEvent has the central concept of a I<watcher>, which is an object that
 stores relevant data for each kind of event you are waiting for, such as
 on true relative time) and absolute (ev_periodic, based on wallclock time)
 timers.
 AnyEvent always prefers relative timers, if available, matching the
 AnyEvent API.
+AnyEvent has two additional methods that return the "current time":
+=over 4
+=item AnyEvent->time
+This returns the "current wallclock time" as a fractional number of
+seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
+return, and the result is guaranteed to be compatible with those).
+It progresses independently of any event loop processing.
+In almost all cases (in all cases if you don't care), this is the function
+to call when you want to know the current time.
+=item AnyEvent->now
+This also returns the "current wallclock time", but unlike C<time>, above,
+this value might change only once per event loop iteration, depending on
+the event loop (most return the same time as C<time>, above). This is the
+time that AnyEvent timers get scheduled against.
+For a practical example of when these times differ, consider L<Event::Lib>
+and L<EV> and the following set-up:
+The event loop is running and has just invoked one of your callback at
+time=500 (assume no other callbacks delay processing). In your callback,
+you wait a second by executing C<sleep 1> (blocking the process for a
+second) and then (at time=501) you create a relative timer that fires
+after three seconds.
+With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
+both return C<501>, because that is the current time, and the timer will
+be scheduled to fire at time=504 (C<501> + C<3>).
+With L<EV>m C<< AnyEvent->time >> returns C<501> (as that is the current
+time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
+last event processing phase started. With L<EV>, your timer gets scheduled
+to run at time=503 (C<500> + C<3>).
+In one sense, L<Event::Lib> is more exact, as it uses the current time
+regardless of any delays introduced by event processing. However, most
+callbacks do not expect large delays in processing, so this causes a
+higher drift (and a lot more syscalls to get the current time).
+In another sense, L<EV> is more exact, as your timer will be scheduled at
+the same time, regardless of how long event processing actually took.
+In either case, if you care (and in most cases, you don't), then you
+can get whatever behaviour you want with any event loop, by taking the
+difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
+account.
+=back
 =head2 SIGNAL WATCHERS
 You can watch for signals using a signal watcher, C<signal> is the signal
 I<name> without any C<SIG> prefix, C<cb> is the Perl callback to
 no warnings;
 use strict;
 use Carp;
-our $VERSION = '4.04';
+our $VERSION = '4.05';
 our $MODEL;
 our $AUTOLOAD;
 our @ISA;
    [POE::Kernel::          => AnyEvent::Impl::POE::],      # lasciate ogni speranza
    [Wx::                   => AnyEvent::Impl::POE::],
    [Prima::                => AnyEvent::Impl::POE::],
 );
-our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);
+our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
 our @post_detect;
 sub post_detect(&) {
    my ($cb) = @_;
    $class->$func (@_);
 }
 package AnyEvent::Base;
+# default implementation for now and time
+use Time::HiRes ();
+sub time { Time::HiRes::time }
+sub now  { Time::HiRes::time }
 # default implementation for ->condvar
 sub condvar {
    bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
 }
 some (broken) firewalls drop such DNS packets, which is why it is off by
 default.
 Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
 EDNS0 in its DNS requests.
+=item C<PERL_ANYEVENT_MAX_FORKS>
+The maximum number of child processes that C<AnyEvent::Util::fork_call>
+will create in parallel.
 =back
 =head1 EXAMPLE PROGRAM

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.140 by root, Mon May 26 06:18:53 2008 UTC vs. Revision 1.143 by root, Wed May 28 23:57:38 2008 UTC

Diff Legend

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.140 by root, Mon May 26 06:18:53 2008 UTC vs.
Revision 1.143 by root, Wed May 28 23:57:38 2008 UTC