@deftypefun {int} {gnutls_x509_crq_get_pk_oid} (gnutls_x509_crq_t @var{crq}, char * @var{oid}, size_t * @var{oid_size}) @var{crq}: should contain a @code{gnutls_x509_crq_t} type @var{oid}: a pointer to a buffer to hold the OID (may be null) @var{oid_size}: initially holds the size of @code{oid} This function will return the OID of the public key algorithm on that certificate request. This function is useful in the case @code{gnutls_x509_crq_get_pk_algorithm()} returned @code{GNUTLS_PK_UNKNOWN} . @strong{Returns:} zero or a negative error code on error. @strong{Since:} 3.5.0 @end deftypefun