const_cast std :: vector [英] const_cast std::vector

问题描述

我有一个向量类型 const std :: vector< const Array *> & objects ，作为参数传递给方法。

I have a vector with type const std::vector<const Array*> &objects which is passed as an argument to the method.

我想要const_cast，但是我不能做某些原因。我试过：

I want to const_cast but I can't do it for some reason. I have tried:

vector< const Array *> obj = const_cast< const std :: vector< const Array *> >（objects）;

和其他一些方法，但它不断抱怨。

and some other ways but it keeps complaining.

任何想法？

推荐答案

t 。更改函数的签名以接受非const引用，您可以通过执行以下操作来风险UB：

Firstly, don't. Change your function's signature to take a non-const reference, you risk UB by doing this:

const std::vector<const Array*> myData = /* fill */;
yourFunction(myData); // try to modify my stuff and you get UB!

---

现在如果你仍然相信，无论什么原因（如传统的API），都是这样做的：

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Now if you are still convinced you have to, for whatever reason (like legacy API), it's done like this:

vector<const Array*>& obj = const_cast<std::vector<const Array*>&>(objects);

现在 obj 和 objects 是指同一个对象，但 obj 不是const限定的。在这一点上，一切都是明确的;它只修改一个const对象是UB，所以要小心。

Now obj and objects refer to the same object, but obj is not const-qualified. At this point, everything is well-defined; it's only modifying a const object that is UB, so be careful.

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