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>