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.TH CURLOPT_CERTINFO 3 "August 22, 2023" "ibcurl 8.3.0" libcurl

.SH NAME
CURLOPT_CERTINFO \- request SSL certificate information
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CERTINFO, long certinfo);
.fi
.SH DESCRIPTION
Pass a long set to 1 to enable libcurl's certificate chain info gatherer. With
this enabled, libcurl extracts lots of information and data about the
certificates in the certificate chain used in the SSL connection. This data
may then be retrieved after a transfer using \fIcurl_easy_getinfo(3)\fP and
its option \fICURLINFO_CERTINFO(3)\fP.
.SH DEFAULT
0
.SH PROTOCOLS
All TLS-based
.SH EXAMPLE
.nf
curl = curl_easy_init();
if(curl) {
  curl_easy_setopt(curl, CURLOPT_URL, "https://www.example.com/");

  /* connect to any HTTPS site, trusted or not */
  curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
  curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);

  curl_easy_setopt(curl, CURLOPT_CERTINFO, 1L);

  res = curl_easy_perform(curl);

  if (!res) {
    struct curl_certinfo *ci;
    res = curl_easy_getinfo(curl, CURLINFO_CERTINFO, &ci);

    if (!res) {
      printf("%d certs!\\n", ci->num_of_certs);

      for(i = 0; i < ci->num_of_certs; i++) {
        struct curl_slist *slist;

        for(slist = ci->certinfo[i]; slist; slist = slist->next)
          printf("%s\\n", slist->data);
      }
    }
  }
  curl_easy_cleanup(curl);
}
.fi
.SH AVAILABILITY
This option is supported by the OpenSSL, GnuTLS, Schannel and Secure
Transport backends. Schannel support added in 7.50.0. Secure Transport support
added in 7.79.0.
.SH RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
.SH "SEE ALSO"
.BR CURLOPT_CAINFO "(3), " CURLOPT_SSL_VERIFYPEER "(3), "