CURLOPT_CERTINFO(3)

CURLOPT_CERTINFO3

Request ssl certificate information

Usage

#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CERTINFO, long certinfo);

Overview

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 curl_easy_getinfo(3) and its option CURLINFO_CERTINFO(3).

Default

0

Protocols

All TLS-based

Examples

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    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) {
        int i;
        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);
  }
}

Return value

Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.

Releases

79 releases since OS X 10.10; the text changed 14 times.

  1. 10.10–10.10.4
  2. 10.10.5–10.11.6
  3. 10.12–10.12.5
  4. 10.12.6–10.14.6
  5. 10.15–11.5
  6. 12.0.1–12.2
  7. 12.3–12.5
  8. 13.0
  9. 13.1
  10. 13.2
  11. 13.3
  12. 13.4
  13. 13.5–14.1
  14. 14.2–14.4
  15. 14.5–26.5

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.

From curl 166.0.0.0.1 in macOS 26.5. Parsed by carta from the page's man source.