Path to certificate authority (ca) bundle
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CAINFO, char *path);
Pass a char * to a zero terminated string naming a file holding one or more certificates to verify the peer with.
If CURLOPT_SSL_VERIFYPEER(3) is zero and you avoid verifying the server's certificate, CURLOPT_CAINFO(3) need not even indicate an accessible file.
This option is by default set to the system path where libcurl's cacert bundle is assumed to be stored, as established at build time.
If curl is built against the NSS SSL library, the NSS PEM PKCS#11 module (libnsspem.so) needs to be available for this option to work properly.
Built-in system specific
All TLS based protocols: HTTPS, FTPS, IMAPS, POP3, SMTPS etc.
If built TLS enabled
Returns CURLE_OK if the option is supported, CURLE_UNKNOWN_OPTION if not, or CURLE_OUT_OF_MEMORY if there was insufficient heap space.