C ++有可能确定指针是否指向有效的对象? [英] C++ Is it possible to determine whether a pointer points to a valid object?
问题描述
我在学习C ++和阅读C ++ Primer。有一个问题我想知道答案:
给定一个指针 p ,你可以确定 p 指向一个有效的对象?如果是,如何?
不,你不能。为什么?因为保持元数据关于什么构成有效指针以及什么不是有效的将是昂贵的,并且在C ++中,你不支付你不想要的。
您不会 检查指针是否有效,因为您知道指针来自哪里,因为它是您的代码的私有部分,控制,或因为您在面向外部的合同中指定它。
I'm learning C++ and reading C++ Primer. There's a question I would like to know the answer:
Given a pointer p, can you determine whether p points to a valid object? If so, how? If not, why not?
Thanks.
No, you can't. Why? Because it would be expensive to maintain meta data about what constitutes a valid pointer and what doesn't, and in C++ you don't pay for what you don't want.
And you don't want to check whether a pointer is valid, because you know where a pointer comes from, either because it's a private part of your code that you control, or because you specified it in your external-facing contracts.
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