CURLOPT_TIMEOUT 设置 cURL 允许执行的最长秒数
CURLOPT_TIMEOUT_MS 设置 cURL 允许执行的最长毫秒数
CURLOPT_CONNECTTIMEOUT 在发起连接前等待的时间，如果设置为 0，则无限等待
CURLOPT_CONNECTTIMEOUT_MS 尝试连接等待的时间，以毫秒为单位。如果设置为 0，则无限等待
CURLOPT_TIMEOUT_MS 在 cURL 7.16.2 中被加入。从 PHP 5.2.3 起可使用。
所以使用的时候请先查看 libcurl 版本 curl --version。
但是这个函数有个 bug，如果时间小于 1000 毫秒也就是 1 秒的话，会立马报错，查看下面说明
If you want cURL to timeout in less than one second, you can use CURLOPT_TIMEOUT_MS, although there is a bug/"feature" on "Unix-like systems" that causes libcurl to timeout immediately if the value is < 1000 ms with the error "cURL Error (28): Timeout was reached". The explanation for this behavior is: "If libcurl is built to use the standard system name resolver, that portion of the transfer will still use full-second resolution for timeouts with a minimum timeout allowed of one second." What this means to PHP developers is "You can use this function without testing it first, because you can't tell if libcurl is using the standard system name resolver (but you can be pretty sure it is)" The problem is that on (Li|U)nix, when libcurl uses the standard name resolver, a SIGALRM is raised during name resolution which libcurl thinks is the timeout alarm. The solution is to disable signals using CURLOPT_NOSIGNAL. Here's an example script that requests itself causing a 10-second delay so you can test timeouts: 增加 curl_setopt($ch, CURLOPT_NOSIGNAL, 1) 可以解决此问题： if (!isset($_GET['foo'])) { // Client $ch = curl_init('http://localhost/timeout.php?foo=bar'); curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); curl_setopt($ch, CURLOPT_NOSIGNAL, 1); curl_setopt($ch, CURLOPT_TIMEOUT_MS, 200); $data = curl_exec($ch); $curl_errno = curl_errno($ch); $curl_error = curl_error($ch); curl_close($ch); if ($curl_errno > 0) { echo "cURL Error ($curl_errno): $curl_errorn"; } else { echo "Data received: $datan"; } } else { // Server sleep(10); echo "Done."; }声明：1、本博客不从事任何主机及服务器租赁业务，不参与任何交易，也绝非中介。博客内容仅记录博主个人感兴趣的服务器测评结果及一些服务器相关的优惠活动，信息均摘自网络或来自服务商主动提供；所以对本博客提及的内容不作直接、间接、法定、约定的保证，博客内容也不具备任何参考价值及引导作用，访问者需自行甄别。2、访问本博客请务必遵守有关互联网的相关法律、规定与规则；不能利用本博客所提及的内容从事任何违法、违规操作；否则造成的一切后果由访问者自行承担。3、未成年人及不能独立承担法律责任的个人及群体请勿访问本博客。4、一旦您访问本博客，即表示您已经知晓并接受了以上声明通告。
