CURLOPT_SSH_HOSTKEYDATA(3) - Man pages

CURLOPT_SSH_HOSTKEYDATA(3)  Library Functions Manual CURLOPT_SSH_HOSTKEYDATA(3)

NAME
       CURLOPT_SSH_HOSTKEYDATA - pointer to pass to the SSH host key callback

SYNOPSIS
       #include <curl/curl.h>

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

DESCRIPTION
       Pass  a  void  * as parameter. This pointer is passed along untouched to
       the callback set with CURLOPT_SSH_HOSTKEYFUNCTION(3).

DEFAULT
       NULL

PROTOCOLS
       This functionality affects scp and sftp

EXAMPLE
       struct mine {
         void *custom;
       };

       static int hostkeycb(void *clientp,   /* CURLOPT_SSH_HOSTKEYDATA */
                            int keytype,     /* CURLKHTYPE */
                            const char *key, /* host key to check */
                            size_t keylen)   /* length of the key */
       {
         /* 'clientp' points to the callback_data struct */
         /* investigate the situation and return the correct value */
         return CURLKHMATCH_OK;
       }

       int main(void)
       {
         CURL *curl = curl_easy_init();
         if(curl) {
           struct mine callback_data;
           curl_easy_setopt(curl, CURLOPT_URL, "sftp://example.com/thisfile.txt");
           curl_easy_setopt(curl, CURLOPT_SSH_HOSTKEYFUNCTION, hostkeycb);
           curl_easy_setopt(curl, CURLOPT_SSH_HOSTKEYDATA, &callback_data);

           curl_easy_perform(curl);
         }
       }

NOTES
       Works only with the libssh2 backend.

AVAILABILITY
       Added in curl 7.84.0

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_SSH_HOSTKEYFUNCTION(3)

libcurl                            2026-07-12        CURLOPT_SSH_HOSTKEYDATA(3)

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