=head1 NAME

IO::Mux::Pipe::Read - read from an external command

=head1 INHERITANCE

 IO::Mux::Pipe::Read
   is a IO::Mux::Handler::Read
   is a IO::Mux::Handler

=head1 SYNOPSIS

  my $mux = IO::Mux::Select->new;  # or ::Poll

  use IO::Mux::Open '-|';
  my $pipe = $mux->open('-|', $command, @cmd_options);

  use IO::Mux::Pipe::Read;
  my $pipe = IO::Mux::Pipe::Read->new
    ( command => [$command, @cmd_options] );
  $mux->add($pipe);

  $pipe->getline(sub {print "$_[0]\n"});

=head1 DESCRIPTION

In an event driven program, reading is harder to use than writing: the
read will very probably be stalled until data has arrived, so you will
need a callback to handle the resulting data.

=head1 METHODS

=head2 Constructors

=over 4

=item IO::Mux::Pipe::Read-E<gt>B<bare>(OPTIONS)

Creates a pipe, but does not start a process (yet). Used by
L<IO::Mux::IPC|IO::Mux::IPC>, which needs three pipes for one process. Returned
is not only a new pipe object, but also a write handle to be
connected to the other side.

All OPTIONS which are available to L<IO::Mux::Handler::Read::new()|IO::Mux::Handler::Read/"Constructors">
can be used here as well.

 -Option   --Default
  read_size  4096

=over 2

=item read_size => INTEGER

=back

example: 

  my ($out, $out_rh)
      = IO::Mux::Pipe::Read->bare(name => 'stdout');

=item IO::Mux::Pipe::Read-E<gt>B<new>(OPTIONS)

 -Option   --Defined in     --Default
  command                     <required>
  fh         IO::Mux::Handler  <required>
  name       IO::Mux::Handler  '$cmd|'
  read_size  IO::Mux::Handler::Read  4096

=over 2

=item command => COMMAND|ARRAY

The external command to be executed. Either the COMMAND needs to
parameters, or you need to pass an ARRAY of the command name and
all its parameters.

=item fh => FILEHANDLE

=item name => STRING

=item read_size => INTEGER

=back

=item IO::Mux::Pipe::Read-E<gt>B<open>(MODE, (CMD, CMDOPTS)|(CMDARRAY, OPTIONS))

Open the pipe to read. MODE is always C<< -| >>.  When you need to
pass additional OPTIONS to the implied L<new()|IO::Mux::Pipe::Read/"Constructors">, then you must use
an ARRAY for command name and its optional parameters.

example: 

  my $mux = IO::Mux::Poll->new;
  $mux->open('-|', 'who', '-H');  # no opts
  $mux->open('-|', ['who', '-H'], %opts);
  $mux->open('-|', 'who');        # no opts
  $mux->open('-|', ['who'], %opts);

=back

=head2 Accessors

=over 4

=item $obj-E<gt>B<childPid>

The process id of the child on the other side of the pipe.

=item $obj-E<gt>B<fh>
See L<IO::Mux::Handler/"Accessors">

=item $obj-E<gt>B<fileno>
See L<IO::Mux::Handler/"Accessors">

=item $obj-E<gt>B<mode>

The bits of the open mode.

=item $obj-E<gt>B<mux>
See L<IO::Mux::Handler/"Accessors">

=item $obj-E<gt>B<name>
See L<IO::Mux::Handler/"Accessors">

=item $obj-E<gt>B<readSize>([INTEGER])
See L<IO::Mux::Handler::Read/"Accessors">

=item $obj-E<gt>B<usesSSL>
See L<IO::Mux::Handler/"Accessors">

=back

=head2 User interface

=head3 Connection

=over 4

=item $obj-E<gt>B<close>([CALLBACK])
See L<IO::Mux::Handler/"Connection">

=item $obj-E<gt>B<timeout>([TIMEOUT])
See L<IO::Mux::Handler/"Connection">

=back

=head3 Reading

=over 4

=item $obj-E<gt>B<readline>(CALLBACK)
See L<IO::Mux::Handler::Read/"Reading">

=item $obj-E<gt>B<slurp>(CALLBACK)
See L<IO::Mux::Handler::Read/"Reading">

=back

=head2 Multiplexer

=head3 Connection

=over 4

=item $obj-E<gt>B<mux_init>(MUX, [HANDLER])
See L<IO::Mux::Handler/"Connection">

=item $obj-E<gt>B<mux_remove>
See L<IO::Mux::Handler/"Connection">

=item $obj-E<gt>B<mux_timeout>
See L<IO::Mux::Handler/"Connection">

=back

=head3 Reading

=over 4

=item $obj-E<gt>B<mux_eof>(INPUT)
See L<IO::Mux::Handler::Read/"Reading">

=item $obj-E<gt>B<mux_except_flagged>(FILENO)
See L<IO::Mux::Handler/"Reading">

=item $obj-E<gt>B<mux_input>(BUFFER)
See L<IO::Mux::Handler::Read/"Reading">

=item $obj-E<gt>B<mux_read_flagged>(FILENO)
See L<IO::Mux::Handler/"Reading">

=back

=head3 Writing

=over 4

=item $obj-E<gt>B<mux_write_flagged>(FILENO)
See L<IO::Mux::Handler/"Writing">

=back

=head3 Service

=head2 Helpers

=over 4

=item $obj-E<gt>B<extractSocket>(HASH)

=item IO::Mux::Pipe::Read-E<gt>B<extractSocket>(HASH)
See L<IO::Mux::Handler/"Helpers">

=item $obj-E<gt>B<fdset>(STATE, READ, WRITE, ERROR)
See L<IO::Mux::Handler/"Helpers">

=item $obj-E<gt>B<show>
See L<IO::Mux::Handler/"Helpers">

=back

=head1 SEE ALSO

This module is part of IO-Mux distribution version 0.11,
built on January 26, 2011. Website: F<http://perl.overmeer.net/>
All modules in this suite:
L</Any::Daemon>,
L</IO::Mux>, and
L</IO::Mux::HTTP>.

Please post questions or ideas to F<perl@overmeer.net>

=head1 LICENSE

Copyrights 2011 by Mark Overmeer. For other contributors see ChangeLog.

This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
See F<http://www.perl.com/perl/misc/Artistic.html>

