---
name: "gnutls_pkcs11_crt_is_known"
section: "3"
platform: "linux"
package: "gnutls"
version: "3.8.13-3"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/gnutls_pkcs11_crt_is_known"
---

# gnutls\_pkcs11\_crt\_is\_known(3)

API function

## NAME

gnutls\_pkcs11\_crt\_is\_known - API function

## SYNOPSIS

**#include \<gnutls/pkcs11.h\>**

**unsigned gnutls\_pkcs11\_crt\_is\_known(const char \*** *url***, gnutls\_x509\_crt\_t** *cert***, unsigned int** *flags***);**

## ARGUMENTS

- const char \* url

  A PKCS 11 url identifying a token

- gnutls\_x509\_crt\_t cert

  is the certificate to find issuer for

- unsigned int flags

  Use zero or flags from **GNUTLS\_PKCS11\_OBJ\_FLAG**.

## DESCRIPTION

This function will check whether the provided certificate is stored in the specified token. This is useful in combination with  **GNUTLS\_PKCS11\_OBJ\_FLAG\_RETRIEVE\_TRUSTED** or **GNUTLS\_PKCS11\_OBJ\_FLAG\_RETRIEVE\_DISTRUSTED**, to check whether a CA is present or a certificate is distrusted in a trust PKCS **11** module.

This function can be used with a  *url* of "pkcs11:", and in that case all modules will be searched. To restrict the modules to the marked as trusted in p11-kit use the **GNUTLS\_PKCS11\_OBJ\_FLAG\_PRESENT\_IN\_TRUSTED\_MODULE** flag.

Note that the flag **GNUTLS\_PKCS11\_OBJ\_FLAG\_RETRIEVE\_DISTRUSTED** is specific to p11-kit trust modules.

## RETURNS

If the certificate exists non-zero is returned, otherwise zero.

## SINCE

3\.3.0

## REPORTING BUGS

Report bugs to \<bugs@gnutls.org\>.\
 Home page: https://www.gnutls.org

## COPYRIGHT

Copyright © 2001-2023 Free Software Foundation, Inc., and others.\
 Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved.

## SEE ALSO

The full documentation for **gnutls** is maintained as a Texinfo manual. If the /usr/share/doc/gnutls/ directory does not contain the HTML form visit

- https://www.gnutls.org/manual/
