CURLOPT_PROXY_TRANSFER_MODE(3) Library Functions Manual NAME CURLOPT_PROXY_TRANSFER_MODE - append FTP transfer mode to URL for proxy SYNOPSIS #include CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_TRANSFER_MODE, long enabled); DESCRIPTION Pass a long. If the value is set to 1 (one), it tells libcurl to set the transfer mode (binary or ASCII) for FTP transfers done via an HTTP proxy, by appending ;type=a or ;type=i to the URL. Without this setting, or it being set to 0 (zero, the default), CURLOPT_TRANSFERTEXT(3) has no effect when doing FTP via a proxy. Beware that not all proxies support this feature. DEFAULT 0, disabled PROTOCOLS This functionality affects all supported protocols EXAMPLE int main(void) { CURL *curl = curl_easy_init(); if(curl) { CURLcode res; curl_easy_setopt(curl, CURLOPT_URL, "ftp://example.com/old-server/file.txt"); curl_easy_setopt(curl, CURLOPT_PROXY, "http://localhost:80"); curl_easy_setopt(curl, CURLOPT_PROXY_TRANSFER_MODE, 1L); curl_easy_setopt(curl, CURLOPT_TRANSFERTEXT, 1L); res = curl_easy_perform(curl); curl_easy_cleanup(curl); } } AVAILABILITY Added in curl 7.18.0 RETURN VALUE curl_easy_setopt(3) returns a CURLcode indicating success or error. CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors(3). SEE ALSO CURLOPT_CRLF(3), CURLOPT_HTTPPROXYTUNNEL(3), CURLOPT_PROXY(3), CURLOPT_TRANSFERTEXT(3) libcurl 2025-02-08 CURLOPT_PROXY_TRANSFER_MODE(3)