c - curl_multi_fdset() 中的 exc_fd_set 是什么？

Question

Curl 的 curl_multi_fdset 函数具有以下声明:

CURLMcode curl_multi_fdset(CURLM *multi_handle,
                           fd_set *read_fd_set,
                           fd_set *write_fd_set,
                           fd_set *exc_fd_set,
                           int *max_fd);

Curl 文档没有解释exc_fd_set 的含义。 exc_fd_set 是什么意思？

Answer 1

我刚刚更新了 curl_multi_fdset()手册页以更好地解释参数的实际用途:

If the read_fd_set argument is not a null pointer, it points to an object of type fd_set that on returns specifies the file descriptors to be checked for being ready to read.

If the write_fd_set argument is not a null pointer, it points to an object of type fd_set that on return specifies the file descriptors to be checked for being ready to write.

If the exc_fd_set argument is not a null pointer, it points to an object of type fd_set that on return specifies the file descriptors to be checked for error conditions pending.