Provided by: libio-async-perl_0.72-1_all bug


       "IO::Async::Handle" - event callbacks for a non-blocking file descriptor


       This class is likely not to be used directly, because subclasses of it exist to handle
       more specific cases. Here is an example of how it would be used to watch a listening
       socket for new connections. In real code, it is likely that the "Loop->listen" method
       would be used instead.

        use IO::Socket::INET;
        use IO::Async::Handle;

        use IO::Async::Loop;
        my $loop = IO::Async::Loop->new;

        my $socket = IO::Socket::INET->new( LocalPort => 1234, Listen => 1 );

        my $handle = IO::Async::Handle->new(
           handle => $socket,

           on_read_ready  => sub {
              my $new_client = $socket->accept;

        $loop->add( $handle );

       For most other uses with sockets, pipes or other filehandles that carry a byte stream, the
       IO::Async::Stream class is likely to be more suitable. For non-stream sockets, see


       This subclass of IO::Async::Notifier allows non-blocking IO on filehandles.  It provides
       event handlers for when the filehandle is read- or write-ready.


       The following events are invoked, either using subclass methods or CODE references in

       Invoked when the read handle becomes ready for reading.

       Invoked when the write handle becomes ready for writing.

       Optional. Invoked when the handle becomes closed.

       This handler is invoked before the filehandles are closed and the Handle removed from its
       containing Loop. The "loop" will still return the containing Loop object.


       The following named parameters may be passed to "new" or "configure":

   read_handle => IO
   write_handle => IO
       The reading and writing IO handles. Each must implement the "fileno" method.  Primarily
       used for passing "STDIN" / "STDOUT"; see the SYNOPSIS section of IO::Async::Stream for an

   handle => IO
       The IO handle for both reading and writing; instead of passing each separately as above.
       Must implement "fileno" method in way that "IO::Handle" does.

   read_fileno => INT
   write_fileno => INT
       File descriptor numbers for reading and writing. If these are given as an alternative to
       "read_handle" or "write_handle" then a new "IO::Handle" instance will be constructed
       around each.

   on_read_ready => CODE
   on_write_ready => CODE
   on_closed => CODE
       CODE references for event handlers.

   want_readready => BOOL
   want_writeready => BOOL
       If present, enable or disable read- or write-ready notification as per the
       "want_readready" and "want_writeready" methods.

       It is required that a matching "on_read_ready" or "on_write_ready" are available for any
       handle that is provided; either passed as a callback CODE reference or as an overridden
       the method. I.e. if only a "read_handle" is given, then "on_write_ready" can be absent. If
       "handle" is used as a shortcut, then both read and write-ready callbacks or methods are

       If no IO handles are provided at construction time, the object is still created but will
       not yet be fully-functional as a Handle. IO handles can be assigned later using the
       "set_handle" or "set_handles" methods, or by "configure". This may be useful when
       constructing an object to represent a network connection, before the connect(2) has
       actually been performed yet.


       The following methods documented with a trailing call to "->get" return Future instances.

          $handle->set_handles( %params )

       Sets new reading or writing filehandles. Equivalent to calling the "configure" method with
       the same parameters.

          $handle->set_handle( $fh )

       Shortcut for

        $handle->configure( handle => $fh )


       This method calls "close" on the underlying IO handles. This method will then remove the
       handle from its containing loop.



       Closes the underlying read or write handle, and deconfigures it from the object. Neither
       of these methods will invoke the "on_closed" event, nor remove the object from the Loop if
       there is still one open handle in the object. Only when both handles are closed, will
       "on_closed" be fired, and the object removed.


       Returns a new IO::Async::Future object which will become done when the handle is closed.
       Cancelling the $future will remove this notification ability but will not otherwise affect
       the $handle.

          $handle = $handle->read_handle

          $handle = $handle->write_handle

       These accessors return the underlying IO handles.

          $fileno = $handle->read_fileno

          $fileno = $handle->write_fileno

       These accessors return the file descriptor numbers of the underlying IO handles.

          $value = $handle->want_readready

          $oldvalue = $handle->want_readready( $newvalue )

          $value = $handle->want_writeready

          $oldvalue = $handle->want_writeready( $newvalue )

       These are the accessor for the "want_readready" and "want_writeready" properties, which
       define whether the object is interested in knowing about read- or write-readiness on the
       underlying file handle.

          $handle->socket( $ai )

       Convenient shortcut to creating a socket handle, as given by an addrinfo structure, and
       setting it as the read and write handle for the object.

       $ai may be either a "HASH" or "ARRAY" reference of the same form as given to
       IO::Async::OS's "extract_addrinfo" method.

       This method returns nothing if it succeeds, or throws an exception if it fails.

          $handle = $handle->bind( %args )->get

       Performs a "getaddrinfo" resolver operation with the "passive" flag set, and then attempts
       to bind a socket handle of any of the return values.

   bind (1 argument)
          $handle = $handle->bind( $ai )->get

       When invoked with a single argument, this method is a convenient shortcut to creating a
       socket handle and "bind()"ing it to the address as given by an addrinfo structure, and
       setting it as the read and write handle for the object.

       $ai may be either a "HASH" or "ARRAY" reference of the same form as given to
       IO::Async::OS's "extract_addrinfo" method.

       The returned future returns the handle object itself for convenience.

          $handle = $handle->connect( %args )->get

       A convenient wrapper for calling the "connect" method on the underlying IO::Async::Loop


       ยท   IO::Handle - Supply object methods for I/O handles


       Paul Evans <>