PHP Curl to check if url is alive

curl_example.php

<?php

function check_alive($url, $timeout = 10, $successOn = array(200, 301)) {
  $ch = curl_init($url);

  // Set request options
  curl_setopt_array($ch, array(
    CURLOPT_FOLLOWLOCATION => false,
    CURLOPT_NOBODY => true,
    CURLOPT_TIMEOUT => $timeout,
    CURLOPT_USERAGENT => "page-check/1.0"
  ));

  // Execute request
  curl_exec($ch);

  // Check if an error occurred
  if(curl_errno($ch)) {
    curl_close($ch);
    return false;
  }

  // Get HTTP response code
  $code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
  curl_close($ch);

  // Page is alive if 200 OK is received
  //return $code;
  return in_array( $code, $successOn );
}

$checks = array(
	'http://www.google.co.uk',
	'http://www.facebook.com',
	'http://www.bbc.co.uk',
	'http://photogabble.co.uk',
	'http://youtube.com'
	);

foreach($checks as $check)
{
	echo $check . ' is ' . ( (check_alive($check) ) ? 'Alive' : 'Dead' ) . "\n";
}

for some reason it don't pick up 404 as an error