CURLOPT_FTP_ALTERNATIVE_TO_USER - command to use instead of USER with FTP
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_FTP_ALTERNATIVE_TO_USER,
Pass a char * as parameter, pointing to a string which will be used to
authenticate if the usual FTP "USER user" and "PASS
password" negotiation fails. This is currently only known to be required
when connecting to Tumbleweed's Secure Transport FTPS server using client
certificates for authentication.
The application does not have to keep the string around after setting this
CURL *curl = curl_easy_init();
curl_easy_setopt(curl, CURLOPT_URL, "ftp://example.com/foo.bin");
curl_easy_setopt(curl, CURLOPT_FTP_ALTERNATIVE_TO_USER, "two users");
ret = curl_easy_perform(curl);
Added in 7.15.5
Returns CURLE_OK if the option is supported, CURLE_UNKNOWN_OPTION if not, or
CURLE_OUT_OF_MEMORY if there was insufficient heap space.