---
name: "gnutls_x509_crt_get_issuer_dn_by_oid"
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_x509_crt_get_issuer_dn_by_oid"
---

# gnutls\_x509\_crt\_get\_issuer\_dn\_by\_oid(3)

API function

## NAME

gnutls\_x509\_crt\_get\_issuer\_dn\_by\_oid - API function

## SYNOPSIS

**#include \<gnutls/x509.h\>**

**int gnutls\_x509\_crt\_get\_issuer\_dn\_by\_oid(gnutls\_x509\_crt\_t** *cert***, const char \*** *oid***, unsigned** *indx***, unsigned int** *raw\_flag***, void \*** *buf***, size\_t \*** *buf\_size***);**

## ARGUMENTS

- gnutls\_x509\_crt\_t cert

  should contain a **gnutls\_x509\_crt\_t** type

- const char \* oid

  holds an Object Identified in null terminated string

- unsigned indx

  In case multiple same OIDs exist in the RDN, this specifies which to send. Use (0) to get the first one.

- unsigned int raw\_flag

  If non-zero returns the raw DER data of the DN part.

- void \* buf

  a pointer to a structure to hold the name (may be null)

- size\_t \* buf\_size

  initially holds the size of  *buf*

## DESCRIPTION

This function will extract the part of the name of the Certificate issuer specified by the given OID. The output, if the raw flag is not used, will be encoded as described in RFC4514. Thus a string that is ASCII or UTF-8 encoded, depending on the certificate data.

Some helper macros with popular OIDs can be found in gnutls/x509.h If raw flag is (0), this function will only return known OIDs as text. Other OIDs will be DER encoded, as described in RFC4514 -- in hex format with a '#' prefix.  You can check about known OIDs using **gnutls\_x509\_dn\_oid\_known()**.

If  *buf* is null then only the size will be filled. If the  *raw\_flag* is not specified the output is always null terminated, although the\
  *buf\_size* will not include the null character.

## RETURNS

**GNUTLS\_E\_SHORT\_MEMORY\_BUFFER** if the provided buffer is not long enough, and in that case the  *buf\_size* will be updated with the required size. **GNUTLS\_E\_REQUESTED\_DATA\_NOT\_AVAILABLE** if there are no data in the current index. On success 0 is returned.

## 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/