use strict;
use warnings;

use IO::Pipe;
use IO::Select;

select( ( select( STDERR ), $| = 1 )[0] );
select( ( select( STDOUT ), $| = 1 )[0] );

my $pipe = new IO::Pipe;

if ( fork() ) {
    print "Parent live\n";
    $pipe->reader();
    my $ios = IO::Select->new();
    $ios->add($pipe);
    while (1) {
        my $handles = scalar( $ios->handles );
        my @fh = $ios->can_read(1);

        print( STDERR
               "Handles: $handles, "
               . scalar(@fh) . " ready\n" );

        foreach ( @fh ) {
            print( STDERR "[r]\n" );
            my $buf = "";
            sysread( $_, $buf, 1024 );
            print( STDERR "[d:$buf:d]\n" );
        }

        if ( ! @fh ) {
            print( STDERR "[b]\n" );
        }
    }
}
else {
    print "Child live\n";
    $pipe->writer();
    $pipe->autoflush(1);

    while (1) {
        $pipe->print("HELLO!");
        print( STDERR "[W]\n" );
        sleep 3;
    }
}