DragonFly On-Line Manual Pages
CURLOPT_CAINFO(3) curl_easy_setopt options CURLOPT_CAINFO(3)
CURLOPT_CAINFO - 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
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. Starting with curl-7.55.0, if both CURLOPT_CAINFO(3) and
CURLOPT_CAPATH(3) are unset, NSS-linked libcurl tries to load
libnssckbi.so, which contains a more comprehensive set of trust
information than supported by nss-pem, because libnssckbi.so also
includes information about distrusted certificates.
(iOS and macOS) If curl is built against Secure Transport, then this
option is supported for backward compatibility with other SSL engines,
but it should not be set. If the option is not set, then curl will use
the certificates in the system and user Keychain to verify the peer,
which is the preferred method of verifying the peer's certificate
(Schannel) This option is supported for Schannel in Windows 7 or later
but we recommend not using it until Windows 8 since it works better
starting then. Added in libcurl 7.60. This option is supported for
backward compatibility with other SSL engines; instead it is
recommended to use Windows' store of root certificates (the default for
The application does not have to keep the string around after setting
Built-in system specific
All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.
CURL *curl = curl_easy_init();
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
curl_easy_setopt(curl, CURLOPT_CAINFO, "/etc/certs/cabundle.pem");
ret = curl_easy_perform(curl);
For SSL engines that don't support certificate files the CURLOPT_CAINFO
option is ignored. Refer to https://curl.haxx.se/docs/ssl-compared.html
Returns CURLE_OK if the option is supported, CURLE_UNKNOWN_OPTION if
not, or CURLE_OUT_OF_MEMORY if there was insufficient heap space.
libcurl 7.65.1 May 12, 2019 CURLOPT_CAINFO(3)