什么阻止fsockopen？

Question

经过半天的努力,我终于通过转换这个功能设法让reCAPTCHA工作了:

function _recaptcha_http_post($host, $path, $data, $port = 80) {

 $req = _recaptcha_qsencode ($data);

 $http_request  = "POST $path HTTP/1.0\r\n";
 $http_request .= "Host: $host\r\n";
 $http_request .= "Content-Type: application/x-www-form-urlencoded;\r\n";
 $http_request .= "Content-Length: " . strlen($req) . "\r\n";
 $http_request .= "User-Agent: reCAPTCHA/PHP\r\n";
 $http_request .= "\r\n";
 $http_request .= $req;

 $response = "";
 if( false == ( $fs = @fsockopen($host, $port, $errno, $errstr, 10) ) ) {
  die ("Could not open socket");
 }

 fwrite($fs, $http_request);

 while ( !feof($fs) )
  $response .= fgets($fs, 1160); // One TCP-IP packet
 fclose($fs);
 $response = explode("\r\n\r\n", $response, 2);
 return $response;
}

至:

function _recaptcha_http_post($host, $path, $data, $port = 80) {
 $req = _recaptcha_qsencode ($data);
 $request = curl_init("http://".$host.$path);

 curl_setopt($request, CURLOPT_USERAGENT, "reCAPTCHA/PHP");
 curl_setopt($request, CURLOPT_POST, true);
 curl_setopt($request, CURLOPT_POSTFIELDS, $req);
 curl_setopt($request, CURLOPT_RETURNTRANSFER, true);

 $response = curl_exec($request);
 return $response;
}

基本上,我有兴趣找出为什么curl工作fsockopen失败时"无法打开套接字".谢谢.

此外:启用了套接字支持.

Answer 1

if(false === ...) 中的 $errno 和 $errstr 是什么？那么，如果更改为，它会输出什么

 if( false == ( $fs = @fsockopen($host, $port, $errno, $errstr, 10) ) ) {
  die ("Could not open socket, error: " . $errstr);
 }