CURLOPT_USE_SSL(3)

📦
version 8.18.0 · 24 versions
, in fedora 44

💅 CURLOPT_USE_SSL(3) — like, the curl library functions manual, bestie 🎀

okay so bestie, welcome to the CURLOPT_USE_SSL page, straight out of the curl Library Functions Manual ✨ this one is literally about telling libcurl "hey, can we do this transfer with SSL / TLS please?" 🦋

✨ NAME ✨

CURLOPT_USE_SSL — request using SSL / TLS for the transfer 💖

🌸 SYNOPSIS 🌸

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_USE_SSL, long level);

💜 DESCRIPTION 💜

So what you do is you pass a long using one of the values from down below ⬇️ and that's how you make libcurl use your desired level of SSL for the transfer. main character energy tbh 👑

these are all protocols that start out plain text and get "upgraded" to SSL using the STARTTLS command. glow-up via negotiation, iconic 🌈

this is for enabling SSL/TLS when you use FTP, SMTP, POP3, IMAP etc. iykyk 💅

  • CURLUSESSL_NONE — do not attempt to use SSL. zero SSL, not even a little bit 🙈
  • CURLUSESSL_TRY — try using SSL, proceed as normal otherwise. but bestie, heads up: the server may close the connection if the negotiation fails 😭💀
  • CURLUSESSL_CONTROL — require SSL for the control connection, or fail with CURLE_USE_SSL_FAILED. no SSL on that control connection? we're not doing it, periodt 🔥
  • CURLUSESSL_ALL — require SSL for all communication, or fail with CURLE_USE_SSL_FAILED. every single bit of the convo is encrypted or we simply don't go 👑✨

🎀 DEFAULT 🎀

CURLUSESSL_NONE

(the default is literally "no SSL", so yeah, you gotta ask for it fr fr 💀)

🦋 PROTOCOLS 🦋

this functionality affects ftp, imap, pop3 and smtp 🌸

⭐ EXAMPLE ⭐

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_URL, "ftp://example.com/dir/file.ext");

    /* require use of SSL for this, or fail */
    curl_easy_setopt(curl, CURLOPT_USE_SSL, CURLUSESSL_ALL);

    /* Perform the request */
    curl_easy_perform(curl);
  }
}

see how it's giving "require use of SSL for this, or fail"? that's CURLUSESSL_ALL doing its thing 💅

💀 HISTORY 💀

  • this option was known as CURLOPT_FTP_SSL up to 7.16.4 🕰️
  • supported by LDAP since 7.81.0
  • fully supported by the OpenLDAP backend only (so, like, know your backend bestie 🫶)
  • CURLUSESSL_* enums became long types in 8.13.0 — prior to this version a long cast was necessary when passed to curl_easy_setopt(3) 😭

🌟 AVAILABILITY 🌟

Added in curl 7.17.0 ✨

👑 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 🌈

and that's the whole page bestie, go forth and negotiate your TLS 🧚💜

later babes — this was libcurl, dated 2026-10-12, mwah 💋

📦 where this page comes from