gnutls_x509_crt_get_issuer_dn_by_oid - API function

       #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 *

       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

       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

       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.

       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.

       Report bugs to <>.
       Home page:

       Copyright © 2001-2020 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.

       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

gnutls                               3.6.gnutls_x509_crt_get_issuer_dn_by_oid(3)