[ViewVC] Diff of: cvs/EV/EV.pm

Comparing EV/EV.pm (file contents):
Revision 1.30 by root, Thu Nov 8 02:19:36 2007 UTC vs.
Revision 1.53 by root, Sat Nov 24 16:57:30 2007 UTC

   my $w = EV::timer 2, 0, sub {
      warn "is called after 2s";
   };
-  my $w = EV::timer 2, 1, sub {
+  my $w = EV::timer 2, 2, sub {
-     warn "is called roughly every 2s (repeat = 1)";
+     warn "is called roughly every 2s (repeat = 2)";
   };
   undef $w; # destroy event watcher again
   my $w = EV::periodic 0, 60, 0, sub {
   };
   # IO
   my $w = EV::io *STDIN, EV::READ, sub {
-     my ($w, $revents) = @_; # all callbacks get the watcher object and event mask
+     my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
      warn "stdin is readable, you entered: ", <STDIN>;
   };
   # SIGNALS
   my $w = EV::signal 'QUIT', sub {
      warn "sigquit received\n";
   };
-  my $w = EV::signal 3, sub {
-     warn "sigquit received (this is GNU/Linux, right?)\n";
-  };
   # CHILD/PID STATUS CHANGES
   my $w = EV::child 666, sub {
      my ($w, $revents) = @_;
-     # my $pid = $w->rpid;
      my $status = $w->rstatus;
   };
   # MAINLOOP
-  EV::loop;                   # loop until EV::loop_done is called
+  EV::loop;           # loop until EV::unloop is called or all watchers stop
   EV::loop EV::LOOP_ONESHOT;  # block until at least one event could be handled
   EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
 =head1 DESCRIPTION
 This module provides an interface to libev
-(L<http://software.schmorp.de/pkg/libev.html>).
+(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
+below is comprehensive, one might also consult the documentation of libev
+itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on
+watcher semantics or some discussion on the available backends, or how to
+force a specific backend with C<LIBEV_FLAGS>.
 =cut
 package EV;
 use strict;
 BEGIN {
-   our $VERSION = '0.51';
+   our $VERSION = '1.3';
    use XSLoader;
    XSLoader::load "EV", $VERSION;
 }
-@EV::Io::ISA       =
+@EV::IO::ISA       =
 @EV::Timer::ISA    =
 @EV::Periodic::ISA =
 @EV::Signal::ISA   =
 @EV::Idle::ISA     =
 @EV::Prepare::ISA  =
 Returns the time the last event loop iteration has been started. This
 is the time that (relative) timers are based on, and refering to it is
 usually faster then calling EV::time.
-=item $method = EV::ev_method
+=item $method = EV::method
 Returns an integer describing the backend used by libev (EV::METHOD_SELECT
 or EV::METHOD_EPOLL).
 =item EV::loop [$flags]
 Begin checking for events and calling callbacks. It returns when a
-callback calls EV::loop_done.
+callback calls EV::unloop.
 The $flags argument can be one of the following:
    0                  as above
    EV::LOOP_ONESHOT   block at most once (wait, but do not loop)
    EV::LOOP_NONBLOCK  do not block at all (fetch/handle events but do not wait)
-=item EV::loop_done [$how]
+=item EV::unloop [$how]
-When called with no arguments or an argument of 1, makes the innermost
+When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
-call to EV::loop return.
+innermost call to EV::loop return.
-When called with an agrument of 2, all calls to EV::loop will return as
+When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
 fast as possible.
+=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
+This function rolls together an I/O and a timer watcher for a single
+one-shot event without the need for managing a watcher object.
+If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
+must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
+| EV::WRITE>, indicating the type of I/O event you want to wait for. If
+you do not want to wait for some I/O event, specify C<undef> for
+C<$fh_or_undef> and C<0> for C<$events>).
+If timeout is C<undef> or negative, then there will be no
+timeout. Otherwise a EV::timer with this value will be started.
+When an error occurs or either the timeout or I/O watcher triggers, then
+the callback will be called with the received event set (in general
+you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>,
+C<EV::WRITE> and C<EV::TIMEOUT>).
+EV::once doesn't return anything: the watchers stay active till either
+of them triggers, then they will be stopped and freed, and the callback
+invoked.
 =back
 =head2 WATCHER
 watchers with higher priority will be invoked first. The valid range of
 priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
 -2). If the priority is outside this range it will automatically be
 normalised to the nearest valid priority.
-The default priority of any newly-created weatcher is 0.
+The default priority of any newly-created watcher is 0.
+Note that the priority semantics have not yet been fleshed out and are
+subject to almost certain change.
 =item $w->trigger ($revents)
 Call the callback *now* with the given event mask.
+=item $previous_state = $w->keepalive ($bool)
+Normally, C<EV::loop> will return when there are no active watchers
+(which is a "deadlock" because no progress can be made anymore). This is
+convinient because it allows you to start your watchers (and your jobs),
+call C<EV::loop> once and when it returns you know that all your jobs are
+finished (or they forgot to register some watchers for their task :).
+Sometimes, however, this gets in your way, for example when you the module
+that calls C<EV::loop> (usually the main program) is not the same module
+as a long-living watcher (for example a DNS client module written by
+somebody else even). Then you might want any outstanding requests to be
+handled, but you would not want to keep C<EV::loop> from returning just
+because you happen to have this long-running UDP port watcher.
+In this case you can clear the keepalive status, which means that even
+though your watcher is active, it won't keep C<EV::loop> from returning.
+The initial value for keepalive is true (enabled), and you cna change it
+any time.
+Example: Register an IO watcher for some UDP socket but do not keep the
+event loop from running just because of that watcher.
+   my $udp_socket = ...
+   my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
+   $udp_watcher->keepalive (0);
 =item $w = EV::io $fileno_or_fh, $eventmask, $callback
 =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
 =item $w = EV::timer $after, $repeat, $callback
 =item $w = EV::timer_ns $after, $repeat, $callback
-Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,
+Calls the callback after C<$after> seconds (which may be fractional). If
-the timer will be restarted (with the $repeat value as $after) after the
+C<$repeat> is non-zero, the timer will be restarted (with the $repeat
-callback returns.
+value as $after) after the callback returns.
 This means that the callback would be called roughly after C<$after>
-seconds, and then every C<$repeat> seconds. "Roughly" because the time of
+seconds, and then every C<$repeat> seconds. The timer does his best not
-callback processing is not taken into account, so the timer will slowly
+to drift, but it will not invoke the timer more often then once per event
-drift. If that isn't acceptable, look at EV::periodic.
+loop iteration, and might drift in other cases. If that isn't acceptable,
+look at EV::periodic, which can provide long-term stable timers.
-The timer is based on a monotonic clock, that is if somebody is sitting
+The timer is based on a monotonic clock, that is, if somebody is sitting
 in front of the machine while the timer is running and changes the system
 clock, the timer will nevertheless run (roughly) the same time.
 The C<timer_ns> variant doesn't start (activate) the newly created watcher.
 =item $w->again
 Similar to the C<start> method, but has special semantics for repeating timers:
+If the timer is active and non-repeating, it will be stopped.
 If the timer is active and repeating, reset the timeout to occur
 C<$repeat> seconds after now.
-If the timer is active and non-repeating, it will be stopped.
-If the timer is in active and repeating, start it.
+If the timer is inactive and repeating, start it using the repeat value.
 Otherwise do nothing.
 This behaviour is useful when you have a timeout for some IO
 operation. You create a timer object with the same value for C<$after> and
 possible time where C<$time = $at (mod $interval)>, regardless of any time
 jumps.
 =item * manual reschedule mode ($reschedule_cb = coderef)
-In this mode $interval and $at are both being ignored. Instead, each time
+In this mode $interval and $at are both being ignored. Instead, each
-the periodic watcher gets scheduled, the first callback ($reschedule_cb)
+time the periodic watcher gets scheduled, the reschedule callback
-will be called with the watcher as first, and the current time as second
+($reschedule_cb) will be called with the watcher as first, and the current
-argument.
+time as second argument.
-I<This callback MUST NOT stop or destroy the event watcher, ever.>
+I<This callback MUST NOT stop or destroy this or any other periodic
+watcher, ever>. If you need to stop it, return 1e30 and stop it
+afterwards.
 It must return the next time to trigger, based on the passed time value
 (that is, the lowest time value larger than to the second argument). It
 will usually be called just before the callback will be triggered, but
 might be called at other times, too.
       # do nothing unless active
       $dispatcher->{_event_queue_h}
          or return;
       # make the dispatcher handle any outstanding stuff
+      ... not shown
       # create an IO watcher for each and every socket
       @snmp_watcher = (
          (map { EV::io $_, EV::READ, sub { } }
              keys %{ $dispatcher->{_descriptors} }),
+         EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
+                     ? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
+                    0, sub { },
       );
-      # if there are any timeouts, also create a timer
-      push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { }
-         if $event->[Net::SNMP::Dispatcher::_ACTIVE];
    };
-The callbacks are irrelevant, the only purpose of those watchers is
+The callbacks are irrelevant (and are not even being called), the
-to wake up the process as soon as one of those events occurs (socket
+only purpose of those watchers is to wake up the process as soon as
-readable, or timer timed out). The corresponding EV::check watcher will then
+one of those events occurs (socket readable, or timer timed out). The
-clean up:
+corresponding EV::check watcher will then clean up:
    our $snmp_check = EV::check sub {
       # destroy all watchers
       @snmp_watcher = ();
       # make the dispatcher handle any new stuff
+      ... not shown
    };
 The callbacks of the created watchers will not be called as the watchers
 are destroyed before this cna happen (remember EV::check gets called
 first).
 =back
 =head1 THREADS
-Threads are not supported by this in any way. Perl pseudo-threads is evil
+Threads are not supported by this module in any way. Perl pseudo-threads
-stuff and must die.
+is evil stuff and must die. As soon as Perl gains real threads I will work
+on thread support for it.
+=head1 FORK
+Most of the "improved" event delivering mechanisms of modern operating
+systems have quite a few problems with fork(2) (to put it bluntly: it is
+not supported and usually destructive). Libev makes it possible to work
+around this by having a function that recreates the kernel state after
+fork in the child.
+On non-win32 platforms, this module requires the pthread_atfork
+functionality to do this automatically for you. This function is quite
+buggy on most BSDs, though, so YMMV. The overhead for this is quite
+negligible, because everything the function currently does is set a flag
+that is checked only when the event loop gets used the next time, so when
+you do fork but not use EV, the overhead is minimal.
+On win32, there is no notion of fork so all this doesn't apply, of course.
 =cut
 our $DIED = sub {
    warn "EV: error in callback (ignoring): $@";
 };
 default_loop
    or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';
-push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
 1;
 =head1 SEE ALSO
-  L<EV::DNS>, L<EV::AnyEvent>.
+  L<EV::DNS>.
 =head1 AUTHOR
  Marc Lehmann <schmorp@schmorp.de>
  http://home.schmorp.de/

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Comparing EV/EV.pm (file contents): Revision 1.30 by root, Thu Nov 8 02:19:36 2007 UTC vs. Revision 1.53 by root, Sat Nov 24 16:57:30 2007 UTC

Diff Legend

Comparing EV/EV.pm (file contents):
Revision 1.30 by root, Thu Nov 8 02:19:36 2007 UTC vs.
Revision 1.53 by root, Sat Nov 24 16:57:30 2007 UTC