| 1. | Use of invalid string can lead to undefined behavior
使用无效的字符串会导致未定义的行为 |
| 2. | Unresolved weak symbols have a zero value
未定义的弱符号具有0值。 |
| 3. | Also notice that the undefined symbol
同时要注意，未定义的符号 |
| 4. | Will be referencing undefined variables
会引用未定义的变量。 |
| 5. | Specifies that the certificate has an undefined name constant
指定证书具有一个未定义的名称常数。 |
| 6. | However , the output of the following example code is undefined
而下面的代码示例的输出却是未定义的： |
| 7. | Nullable types allow a variable to contain a value that is undefined
可空类型允许变量包含未定义的值。 |
| 8. | A null value is useful to indicate an undefined or unknown value
空值对于指示未定义的或未知的值很有用。 |
| 9. | A nullable type can contain a value , or it can be undefined . the
可空类型可以包含值，或者可以是未定义的。 |
| 10. | Data sources that are empty or undefined do not appear in this list
为空或未定义的数据源不显示在此列表中。 |
