SR_PRIV int std_double_tuple_idx(GVariant *data, const double a[][2], unsigned int n);
SR_PRIV int std_double_tuple_idx_d0(const double d, const double a[][2], unsigned int n);
SR_PRIV int std_double_tuple_idx(GVariant *data, const double a[][2], unsigned int n);
SR_PRIV int std_double_tuple_idx_d0(const double d, const double a[][2], unsigned int n);