PHP Codeigniter curl_multi_init错误

这是我的代码：

class facebookConnection {

            // Allow multi-threading.

            private $_mch = NULL;
            private $_properties = array();

            function __construct()
            {

                        $this->_mch = curl_multi_init();

                $this->_properties = array(
                    'code'      => CURLINFO_HTTP_CODE,
                    'time'      => CURLINFO_TOTAL_TIME,
                    'length'    => CURLINFO_CONTENT_LENGTH_DOWNLOAD,
                    'type'      => CURLINFO_CONTENT_TYPE
                );
            }

我得到了Fatal error: Call to undefined function curl_multi_init() in /var/www/application/libraries/facebook.php on line 123 这是在我的本地机器上运行...这可能是个问题吗？我不明白。