sub reader_thread {
    my ($hr,$who) = @_;
	
    my $c;
    my $h;
    my $r;
    my $q;

    threads->detach();

    # determine handle.
    if( $who eq 'o' ){
	$h = $hr->{'stdout'};
    } else {
	$h = $hr->{'stderr'};
    }
    # Get the output queue
    $q = $hr->{'Q'};

    while( 1 ){
	if( $hr->{'alive'} == 0 ){
	    last;
	}
	# Try to read *ONE* byte
	$r = read( $h, $c, 1 );
	if( $r > 0 ){
	    if( length($c) ){
		$q->enqueue($c);
	    }
	} else {
	    threads->yield();
	}
    }
}