If a regular expression contains a backreference to an undefined group number , it is considered a parsing error 如果正则表达式包含对未定义的组成员的反向引用，则它被视作分析错误。
If a group has not captured any substring , a backreference to that group is undefined and never matches 如果一个组尚未捕获任何子字符串，则对该组的反向引用是未定义的并且永远不匹配。
In many programming applications , most notably database interactions , variables can exist in an undefined state 在很多编程应用中（最突出的是数据库交互） ，变量可存在于未定义的状态。
They hold only one piece of data : a string , a number , the undefined value , a reference to another variable 它只保存一段数据：一个字符串、一个数字、未定义的值以及对另一个变量的引用。
If the buffered stream is expanded , the contents of the buffered stream between the old and the new lengths are not defined 如果缓冲流被扩展，则缓冲流的新旧长度之间的内容是未定义的。
Specify that a connection will be made using the current security context of the login for logins not defined in the list 指定对于列表中未定义的登录，使用登录的当前安全上下文建立连接。
In addition , because perl is looking for a true value , it also ignores undefined values without complaining about them 另外，由于perl正在寻找一个真值，因此它也可以忽略未定义的值，而不会抱怨这些值尚未定义。
If neither the filter nor the comparator are specified , the enumeration will traverse all records in the record store in an undefined order 如果既没有指定过滤器又没有指定比较器，枚举将以未定义的顺序遍历记录存储中的所有记录。
Explains the concept of undefined values , how to determine if a variable or property is undefined , and how to undefine variables and properties 解释未定义值的概念、如何确定变量或属性是否是未定义的，以及如何取消定义变量和属性。
To resolve this condition consumer endpoint is connected to a web service provider endpoint that has an operation referencing an undefined type 使用者终结点连接到一个web服务提供者终结点，而该终结点有一个引用未定义的类型的操作。
