CURLOPT_SSH_HOSTKEYDATA - pointer to pass to the SSH host key callback

Added in curl 7.84.0

NULL

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

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); } }

CURLOPT_SSH_HOSTKEYDATA - pointer to pass to the SSH host key callback

Works only with the libssh2 backend.

This functionality affects scp and sftp

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).

CURLOPT_SSH_HOSTKEYFUNCTION(3) libcurl 2025-06-16 CURLOPT_SSH_HOSTKEYDATA(3)

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