从 lynx_value 中读取 double 值
lynx_api_status lynx_value_get_double(lynx_api_env env, lynx_value value, double* result);
Returns lynx_api_ok if the API succeeded. Returns lynx_api_double_expected if the types do not match.
lynx_api_ok
lynx_api_double_expected
double ret; lynx_api_status status = lynx_value_get_double(env, value, &ret); if (status != lynx_api_ok) { // handle error. }