@deftypefun {int} {gnutls_x509_crt_get_issuer_dn} (gnutls_x509_crt_t @var{cert}, char * @var{buf}, size_t * @var{buf_size})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  type

@var{buf}: a pointer to a structure to hold the name (may be null)

@var{buf_size}: initially holds the size of  @code{buf} 

This function will copy the name of the Certificate issuer in the
provided buffer. The name will be in the form
"C=xxxx,O=yyyy,CN=zzzz" as described in RFC4514. The output string
will be ASCII or UTF-8 encoded, depending on the certificate data.

If  @code{buf} is null then only the size will be filled.

This function does not output a fully RFC4514 compliant string, if
that is required see @code{gnutls_x509_crt_get_issuer_dn3()} .

@strong{Returns:} @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if the provided buffer is not
long enough, and in that case the  @code{buf_size} will be updated
with the required size. @code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE}  if
the DN does not exist, or another error value on error. On success 0 is returned.
@end deftypefun