@deftypefun {int} {gnutls_certificate_get_issuer} (gnutls_certificate_credentials_t @var{sc}, gnutls_x509_crt_t @var{cert}, gnutls_x509_crt_t * @var{issuer}, unsigned int @var{flags}) @var{sc}: is a @code{gnutls_certificate_credentials_t} type. @var{cert}: is the certificate to find issuer for @var{issuer}: Will hold the issuer if any. Should be treated as constant. @var{flags}: Use zero or @code{GNUTLS_TL_GET_COPY} This function will return the issuer of a given certificate. If the flag @code{GNUTLS_TL_GET_COPY} is specified a copy of the issuer will be returned which must be freed using @code{gnutls_x509_crt_deinit()} . In that case the provided @code{issuer} must not be initialized. As with @code{gnutls_x509_trust_list_get_issuer()} this function requires the @code{GNUTLS_TL_GET_COPY} flag in order to operate with PKCS@code{11} trust lists in a thread-safe way. @strong{Returns:} On success, @code{GNUTLS_E_SUCCESS} (0) is returned, otherwise a negative error value. @strong{Since:} 3.0 @end deftypefun