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    BSDs). Modules should, unless they have "special needs" always use the
    default loop as this is fastest (perl-wise), best supported by other
    modules (e.g. AnyEvent or Coro) and most portable event loop.

    For specific programs you can create additional event loops dynamically.

    If you want to take advantage of kqueue (which often works properly for
    sockets only) even though the default loop doesn't enable it, you can
    *embed* a kqueue loop into the default loop: running the default loop
    will then also service the kqueue loop to some extent. See the example
    in the section about embed watchers for an example on how to achieve
    that.

    $loop = new EV::Loop [$flags]
        Create a new event loop as per the specified flags. Please refer to
        the "ev_loop_new ()" function description in the libev documentation
        (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI
        ONS>, or locally-installed as EV::libev manpage) for more info.

        The loop will automatically be destroyed when it is no longer
        referenced by any watcher and the loop object goes out of scope.

        If you are not embedding the loop, then using "EV::FLAG_FORKCHECK"
        is recommended, as only the default event loop is protected by this
        module. If you *are* embedding this loop in the default loop, this
        is not necessary, as "EV::embed" automatically does the right thing
        on fork.

    $loop->loop_fork
        Must be called after a fork in the child, before entering or
        continuing the event loop. An alternative is to use
        "EV::FLAG_FORKCHECK" which calls this function automatically, at
        some performance loss (refer to the libev documentation).

    $loop->verify
        Calls "ev_verify" to make internal consistency checks (for debugging
        libev) and abort the program if any data structures were found to be
        corrupted.

    $loop = EV::default_loop [$flags]
        Return the default loop (which is a singleton object). Since this
        module already creates the default loop with default flags,
        specifying flags here will not have any effect unless you destroy
        the default loop first, which isn't supported. So in short: don't do
        it, and if you break it, you get to keep the pieces.

BASIC INTERFACE
    $EV::DIED
        Must contain a reference to a function that is called when a
        callback throws an exception (with $@ containing the error). The
        default prints an informative message and continues.

        If this callback throws an exception it will be silently ignored.

    $flags = EV::supported_backends
    $flags = EV::recommended_backends
    $flags = EV::embeddable_backends
        Returns the set (see "EV::BACKEND_*" flags) of backends supported by
        this instance of EV, the set of recommended backends (supposed to be
        good) for this platform and the set of embeddable backends (see
        EMBED WATCHERS).

    EV::sleep $seconds
        Block the process for the given number of (fractional) seconds.

    $time = EV::time
        Returns the current time in (fractional) seconds since the epoch.

    $time = EV::now
    $time = $loop->now
        Returns the time the last event loop iteration has been started.
        This is the time that (relative) timers are based on, and referring
        to it is usually faster then calling EV::time.

    EV::now_update
    $loop->now_update
        Establishes the current time by querying the kernel, updating the
        time returned by "EV::now" in the progress. This is a costly
        operation and is usually done automatically within "EV::run".

        This function is rarely useful, but when some event callback runs
        for a very long time without entering the event loop, updating
        libev's idea of the current time is a good idea.

    EV::suspend
    $loop->suspend
    EV::resume
    $loop->resume
        These two functions suspend and resume a loop, for use when the loop
        is not used for a while and timeouts should not be processed.

        A typical use case would be an interactive program such as a game:
        When the user presses "^Z" to suspend the game and resumes it an
        hour later it would be best to handle timeouts as if no time had
        actually passed while the program was suspended. This can be
        achieved by calling "suspend" in your "SIGTSTP" handler, sending
        yourself a "SIGSTOP" and calling "resume" directly afterwards to
        resume timer processing.

        Effectively, all "timer" watchers will be delayed by the time spend
        between "suspend" and "resume", and all "periodic" watchers will be
        rescheduled (that is, they will lose any events that would have
        occured while suspended).

        After calling "suspend" you must not call *any* function on the
        given loop other than "resume", and you must not call "resume"
        without a previous call to "suspend".

        Calling "suspend"/"resume" has the side effect of updating the event
        loop time (see "now_update").

    $backend = EV::backend
    $backend = $loop->backend
        Returns an integer describing the backend used by libev
        (EV::BACKEND_SELECT or EV::BACKEND_EPOLL).

    $active = EV::run [$flags]
    $active = $loop->run ([$flags])
        Begin checking for events and calling callbacks. It returns when a
        callback calls EV::break or the flags are nonzero (in which case the
        return value is true) or when there are no active watchers which

README  view on Meta::CPAN

                 or return;

              # make the dispatcher handle any outstanding stuff
              ... not shown

              # create an I/O 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 { },
              );
           };

        The callbacks are irrelevant (and are not even being called), the
        only purpose of those watchers is to wake up the process as soon as
        one of those events occurs (socket readable, or timer timed out).
        The 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 can happen (remember EV::check
        gets called first).

        The "check_ns" variant doesn't start (activate) the newly created
        watcher.

    EV::CHECK constant issues
        Like all other watcher types, there is a bitmask constant for use in
        $revents and other places. The "EV::CHECK" is special as it has the
        same name as the "CHECK" sub called by Perl. This doesn't cause big
        issues on newer perls (beginning with 5.8.9), but it means thatthe
        constant must be *inlined*, i.e. runtime calls will not work. That
        means that as long as you always "use EV" and then "EV::CHECK" you
        are on the safe side.

   FORK WATCHERS - the audacity to resume the event loop after a fork
    Fork watchers are called when a "fork ()" was detected. The invocation
    is done before the event loop blocks next and before "check" watchers
    are being called, and only in the child after the fork.

    $w = EV::fork $callback
    $w = EV::fork_ns $callback
    $w = $loop->fork ($callback)
    $w = $loop->fork_ns ($callback)
        Call the callback before the event loop is resumed in the child
        process after a fork.

        The "fork_ns" variant doesn't start (activate) the newly created
        watcher.

   EMBED WATCHERS - when one backend isn't enough...
    This is a rather advanced watcher type that lets you embed one event
    loop into another (currently only IO events are supported in the
    embedded loop, other types of watchers might be handled in a delayed or
    incorrect fashion and must not be used).

    See the libev documentation at
    <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code
    _when_one_backend_> (locally installed as EV::libev) for more details.

    In short, this watcher is most useful on BSD systems without working
    kqueue to still be able to handle a large number of sockets:

       my $socket_loop;
  
       # check wether we use SELECT or POLL _and_ KQUEUE is supported
       if (
         (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
         && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
       ) {
         # use kqueue for sockets
         $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
       }
  
       # use the default loop otherwise
       $socket_loop ||= EV::default_loop;

    $w = EV::embed $otherloop[, $callback]
    $w = EV::embed_ns $otherloop[, $callback]
    $w = $loop->embed ($otherloop[, $callback])
    $w = $loop->embed_ns ($otherloop[, $callback])
        Call the callback when the embedded event loop ($otherloop) has any
        I/O activity. The $callback is optional: if it is missing, then the
        embedded event loop will be managed automatically (which is
        recommended), otherwise you have to invoke "sweep" yourself.

        The "embed_ns" variant doesn't start (activate) the newly created
        watcher.

   ASYNC WATCHERS - how to wake up another event loop
    Async watchers are provided by EV, but have little use in perl directly,
    as perl neither supports threads running in parallel nor direct access
    to signal handlers or other contexts where they could be of value.

    It is, however, possible to use them from the XS level.

    Please see the libev documentation for further details.

    $w = EV::async $callback
    $w = EV::async_ns $callback
    $w = $loop->async ($callback)
    $w = $loop->async_ns ($callback)
    $w->send
    $bool = $w->async_pending

   CLEANUP WATCHERS - how to clean up when the event loop goes away
    Cleanup watchers are not supported on the Perl level, they can only be
    used via XS currently.

PERL SIGNALS
    While Perl signal handling (%SIG) is not affected by EV, the behaviour