@deftypefun {int} {gnutls_x509_crq_get_attribute_by_oid} (gnutls_x509_crq_t @var{crq}, const char * @var{oid}, unsigned @var{indx}, void * @var{buf}, size_t * @var{buf_size})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  type

@var{oid}: holds an Object Identifier in null-terminated string

@var{indx}: In case multiple same OIDs exist in the attribute list, this
specifies which to get, use (0) to get the first one

@var{buf}: a pointer to a structure to hold the attribute data (may be @code{NULL} )

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

This function will return the attribute in the certificate request
specified by the given Object ID.  The attribute will be DER
encoded.

Attributes in a certificate request is an optional set of data
appended to the request. Their interpretation depends on the CA policy.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, otherwise a
negative error value.
@end deftypefun