Curl返回false

Curl请求：

　　　　 $postUrl = $url;
        $curlPost = $param;
        $curl = curl_init();//初始化curl
        curl_setopt($curl, CURLOPT_URL,$postUrl);//抓取指定网页
        curl_setopt($curl, CURLOPT_HEADER, 0);//设置header
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);//要求结果为字符串且输出到屏幕上
        curl_setopt($curl, CURLOPT_POST, 1);//post提交方式
        curl_setopt($curl, CURLOPT_POSTFIELDS, $curlPost);
        $data = curl_exec($curl);//运行curl
        curl_close($curl);
        return $data;

请求结果：bool(false)
原因：$postUrl为https，https有SSL（安全套接层协议层 ），那么不验证SSL就OK了。

        $postUrl = $url;
        $curlPost = $param;
        $curl = curl_init();//初始化curl
        curl_setopt($curl, CURLOPT_URL,$postUrl);//抓取指定网页
        curl_setopt($curl, CURLOPT_HEADER, 0);//设置header
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);//要求结果为字符串且输出到屏幕上
        curl_setopt($curl, CURLOPT_POST, 1);//post提交方式
        curl_setopt($curl, CURLOPT_POSTFIELDS, $curlPost);
        curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false); //不验证证书下同
        curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false); 
        $data = curl_exec($curl);//运行curl
        curl_close($curl);
        return $data;