@deftypefun {int} {gnutls_x509_trust_list_add_system_trust} (gnutls_x509_trust_list_t @var{list}, unsigned int @var{tl_flags}, unsigned int @var{tl_vflags}) @var{list}: The structure of the list @var{tl_flags}: GNUTLS_TL_* @var{tl_vflags}: gnutls_certificate_verify_flags if flags specifies GNUTLS_TL_VERIFY_CRL This function adds the system's default trusted certificate authorities to the trusted list. Note that on unsupported systems this function returns @code{GNUTLS_E_UNIMPLEMENTED_FEATURE} . This function implies the flag @code{GNUTLS_TL_NO_DUPLICATES} . @strong{Returns:} The number of added elements or a negative error code on error. @strong{Since:} 3.1 @end deftypefun