---
name: "CURLOPT_CERTINFO"
section: "3"
platform: "macos"
package: "curl"
version: "166.0.0.0.1"
release: "macOS 26.5"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/CURLOPT_CERTINFO"
---

# CURLOPT\_CERTINFO(3)

request SSL certificate information

## NAME

CURLOPT\_CERTINFO - request SSL certificate information

## SYNOPSIS

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

## 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 *[curl\_easy\_getinfo(3)](/curl_easy_getinfo/3.md)* and its option *[CURLINFO\_CERTINFO(3)](/CURLINFO_CERTINFO/3.md)*.

## DEFAULT

0

## PROTOCOLS

All TLS-based

## EXAMPLE

```
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);
  }
}
```

## 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.

## RETURN VALUE

Returns CURLE\_OK if the option is supported, and CURLE\_UNKNOWN\_OPTION if not.

## SEE ALSO

[**CURLINFO\_CAINFO**(3)](/CURLINFO_CAINFO/3.md), [**CURLINFO\_CAPATH**(3)](/CURLINFO_CAPATH/3.md), [**CURLINFO\_CERTINFO**(3)](/CURLINFO_CERTINFO/3.md), [**CURLOPT\_CAINFO**(3)](/CURLOPT_CAINFO/3.md), [**CURLOPT\_SSL\_VERIFYPEER**(3)](/CURLOPT_SSL_VERIFYPEER/3.md)