Used in conjuction with [curl->set], pass a zero terminated string naming a file holding one or more certificates to verify the peer with. This makes sense only when used in combination with the CURLOPT_SSL_VERIFYPEER option. If CURLOPT_SSL_VERIFYPEER is zero, CURLOPT_CAINFO 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.