PHP에서 URL이 정상적으로 열릴 수 있는지 확인하는 방법

<?php
/*
 * Created on 2016-9-4
 *
 */
 function httpcode($url){
  $ch = curl_init();
  $timeout = 3;
  curl_setopt($ch,CURLOPT_FOLLOWLOCATION,1);
  curl_setopt($ch,CURLOPT_RETURNTRANSFER,1);
  curl_setopt($ch, CURLOPT_HEADER, 1);
  curl_setopt ($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
  curl_setopt($ch,CURLOPT_URL,$url);
  curl_exec($ch);
  return $httpcode = curl_getinfo($ch,CURLINFO_HTTP_CODE);
  curl_close($ch);
}
echo "判断PHP中文网的链接：".httpcode(&#39;//m.sbmmt.com&#39;);
?>
<br/>
如果显示为200则正常，如果显示其它值表示不正常；$timeout后面的3是设置超时秒数。