oracular (3) IO::Async::Loop::Poll.3pm.gz

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>