NAME

       "IO::Async::Loop::Poll" - use "IO::Async" with "poll(2)"

SYNOPSIS

       Normally an instance of this class would not be directly constructed by a program. It may
       however, be useful for runinng IO::Async with an existing program already using an
       "IO::Poll" object.

        use IO::Poll;
        use IO::Async::Loop::Poll;

        my $poll = IO::Poll->new;
        my $loop = IO::Async::Loop::Poll->new( poll => $poll );

        $loop->add( ... );

        while(1) {
           my $timeout = ...
           my $ret = $poll->poll( $timeout );
           $loop->post_poll;
        }

DESCRIPTION

       This subclass of IO::Async::Loop uses the poll(2) system call to perform read-ready and
       write-ready tests.

       By default, this loop will use the underlying "poll()" system call directly, bypassing the
       usual IO::Poll object wrapper around it because of a number of bugs and design flaws in
       that class; namely

       • <https://rt.cpan.org/Ticket/Display.html?id=93107> - IO::Poll relies on stable
         stringification of IO handles

       • <https://rt.cpan.org/Ticket/Display.html?id=25049> - IO::Poll->poll() with no handles
         always returns immediately

       However, to integrate with existing code that uses an "IO::Poll" object, a "post_poll" can
       be called immediately after the "poll" method that "IO::Poll" object. The appropriate mask
       bits are maintained on the "IO::Poll" object when notifiers are added or removed from the
       loop, or when they change their "want_*" status. The "post_poll" method inspects the
       result bits and invokes the "on_read_ready" or "on_write_ready" methods on the notifiers.

CONSTRUCTOR

   new
          $loop = IO::Async::Loop::Poll->new( %args )

       This function returns a new instance of a "IO::Async::Loop::Poll" object. It takes the
       following named arguments:

       "poll"  The "IO::Poll" object to use for notification. Optional; if a value is not given,
               the underlying "IO::Poll::_poll()" function is invoked directly, outside of the
               object wrapping.

METHODS

   post_poll
          $count = $loop->post_poll

       This method checks the returned event list from a "IO::Poll::poll" call, and calls any of
       the notification methods or callbacks that are appropriate.  It returns the total number
       of callbacks that were invoked; that is, the total number of "on_read_ready" and
       "on_write_ready" callbacks for "watch_io", and "watch_time" event callbacks.

   loop_once
          $count = $loop->loop_once( $timeout )

       This method calls the "poll" method on the stored "IO::Poll" object, passing in the value
       of $timeout, and then runs the "post_poll" method on itself. It returns the total number
       of callbacks invoked by the "post_poll" method, or "undef" if the underlying "poll" method
       returned an error.

AUTHOR

       Paul Evans <leonerd@leonerd.org.uk>