GNURLOPT_SSH_KEYDATA(3)

✨ GNURLOPT_SSH_KEYDATA(3) ✨

okay so this is a page from the curl_easy_setopt options manual, bestie — yes that curl, the one your whole internet runs on — and today's topic is a lil' pointer that just... rides along. 🎀

---

💖 NAME 💖

CURLOPT_SSH_KEYDATA — the pointer you hand off to the SSH key callback, no questions asked, no cap 🫶

🌸 SYNOPSIS 🌸

#include <gnurl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSH_KEYDATA, void
*pointer);

🦋 DESCRIPTION 🦋

so you pass a void * as the parameter. mmm yes pointer, iconic behavior. 💅

and then? that pointer gets passed along verbatim to the callback you set with CURLOPT_SSH_KEYFUNCTION(3). verbatim verbatim. like, it doesn't get touched, it doesn't get copied, it doesn't get judged — it just shows up at the callback like "hi i'm here 💁". lowkey the most loyal option in the whole set ngl ✨

🧚 DEFAULT 🧚

NULL

(empty. blank. no pointer. it's giving "nothing to see here" 😭)

👑 PROTOCOLS 👑

SFTP and SCP — ssh vibes only bestie 🌈

🍓 EXAMPLE 🍓

ok so here's the whole moment, look at it:

static int keycb(CURL *easy,
                 const struct curl_khkey *knownkey,
                 const struct curl_khkey *foundkey,
                 enum curl_khmatch,
                 void *clientp)
{
  /* 'clientp' points to the callback_data struct */
  /* investigate the situation and return the correct value */
  return CURLKHSTAT_FINE_ADD_TO_FILE;
}
{
  curl_easy_setopt(curl, CURLOPT_URL, "sftp://example.com/thisfile.txt");
  curl_easy_setopt(curl, CURLOPT_SSH_KEYFUNCTION, keycb);
  curl_easy_setopt(curl, CURLOPT_SSH_KEYDATA, &callback_data);
  curl_easy_setopt(curl, CURLOPT_SSH_KNOWNHOSTS, "/home/user/known_hosts");

  curl_easy_perform(curl);
}

see how &callback_data goes in as the keydata and then comes out the other side as clientp? yeah. that's the whole bit. the way that pointer just travels 😭🫶

⭐ AVAILABILITY ⭐

added in 7.19.6 — retro, vintage, a classic 💜

🔥 RETURN VALUE 🔥

returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not. like, either we slay or we don't, there is no third option. 💀

🌈 SEE ALSO 🌈

• CURLOPT_SSH_KEYDATA(3)
• CURLOPT_SSH_KNOWNHOSTS(3)

ok tiny heads up bestie — yeah that's the option itself listed in its own SEE ALSO, that's just what the page says, i don't make the rules 🙈

---

and that's the page!! 🎀✨

this whole thing is from libcurl 7.37.0, dated 19 Jun 2014 — so if you're reading this in a group chat sometime later, know the lore is old but the vibes are forever 💅🦋⭐