@deftypefun {int} {gnutls_psk_set_server_credentials_file} (gnutls_psk_server_credentials_t @var{res}, const char * @var{password_file}) @var{res}: is a @code{gnutls_psk_server_credentials_t} type. @var{password_file}: is the PSK password file (passwd.psk) This function sets the password file, in a @code{gnutls_psk_server_credentials_t} type. This password file holds usernames and keys and will be used for PSK authentication. @strong{Returns:} On success, @code{GNUTLS_E_SUCCESS} (0) is returned, otherwise an error code is returned. @end deftypefun