NAME

       CURLOPT_PROXY_CAINFO - path to proxy Certificate Authority (CA) bundle

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_CAINFO, char *path);

DESCRIPTION

       This option is for connecting to an HTTPS proxy, not an HTTPS server.

       Pass  a char pointer to a null-terminated string naming a file holding one or more certificates to verify
       the HTTPS proxy with.

       If  CURLOPT_PROXY_SSL_VERIFYPEER(3)  is  zero  and  you  avoid  verifying   the   server's   certificate,
       CURLOPT_PROXY_CAINFO(3) need not even indicate an accessible file.

       This  option  is by default set to the system path where libcurl's CA certificate bundle is assumed to be
       stored, as established at build time.

       (iOS and macOS only) 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 uses the certificates in the system and user Keychain to verify the peer,  which  is  the  preferred
       method of verifying the peer's certificate chain.

       The application does not have to keep the string around after setting this option.

       The default value for this can be figured out with CURLINFO_CAINFO(3).

DEFAULT

       Built-in system specific

PROTOCOLS

       This functionality affects all TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.

       All TLS backends support this option.

EXAMPLE

       int main(void)
       {
         CURL *curl = curl_easy_init();
         if(curl) {
           CURLcode res;
           curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
           /* using an HTTPS proxy */
           curl_easy_setopt(curl, CURLOPT_PROXY, "https://localhost:443");
           curl_easy_setopt(curl, CURLOPT_PROXY_CAINFO, "/etc/certs/cabundle.pem");
           res = curl_easy_perform(curl);
           curl_easy_cleanup(curl);
         }
       }

NOTES

       For  TLS  backends  that do not support certificate files, the CURLOPT_PROXY_CAINFO(3) option is ignored.
       Refer to https://curl.se/docs/ssl-compared.html

AVAILABILITY

       Added in curl 7.52.0

RETURN VALUE

       Returns CURLE_OK if the option is supported, CURLE_UNKNOWN_OPTION if not, or CURLE_OUT_OF_MEMORY if there
       was insufficient heap space.

SEE ALSO

       CURLOPT_CAINFO(3),      CURLOPT_CAINFO_BLOB(3),      CURLOPT_CAPATH(3),     CURLOPT_PROXY_CAINFO_BLOB(3),
       CURLOPT_PROXY_CAPATH(3),        CURLOPT_PROXY_SSL_VERIFYHOST(3),         CURLOPT_PROXY_SSL_VERIFYPEER(3),
       CURLOPT_SSL_VERIFYHOST(3), CURLOPT_SSL_VERIFYPEER(3)