---
name: "CURLOPT_SSH_KEYDATA"
section: "3"
platform: "linux"
package: "curl"
version: "8.23.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/CURLOPT_SSH_KEYDATA"
---

# CURLOPT\_SSH\_KEYDATA(3)

pointer passed to the SSH key callback

## NAME

CURLOPT\_SSH\_KEYDATA - pointer passed to the SSH key callback

## SYNOPSIS

```
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSH_KEYDATA, void *pointer);
```

## DESCRIPTION

Pass a void \* as parameter. This *pointer* is passed along verbatim to the callback set with *[CURLOPT\_SSH\_KEYFUNCTION(3)](/CURLOPT_SSH_KEYFUNCTION/3.md)*.

## DEFAULT

NULL

## PROTOCOLS

This functionality affects scp and sftp

## EXAMPLE

```
struct mine {
  void *custom;
};
static int keycb(CURL *easy,
                 const struct curl_khkey *knownkey,
                 const struct curl_khkey *foundkey,
                 enum curl_khmatch match,
                 void *clientp)
{
  /* 'clientp' points to the callback_data struct */
  /* investigate the situation and return the correct value */
  return CURLKHSTAT_FINE_ADD_TO_FILE;
}
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    struct mine callback_data;
    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");
    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}
```

## AVAILABILITY

Added in curl 7.19.6

## RETURN VALUE

*[curl\_easy\_setopt(3)](/curl_easy_setopt/3.md)* returns a CURLcode indicating success or error.

CURLE\_OK (0) means everything was OK, non-zero means an error occurred, see *[libcurl-errors(3)](/libcurl-errors/3.md)*.

## SEE ALSO

[**CURLOPT\_SSH\_KEYDATA**(3)](/CURLOPT_SSH_KEYDATA/3.md), [**CURLOPT\_SSH\_KNOWNHOSTS**(3)](/CURLOPT_SSH_KNOWNHOSTS/3.md)