如何解释C ++ / CLI中的^表达式 [英] How to interpret the ^ expression in C++/CLI

问题描述

我的代码库中有以下C ++ / CLI代码。



请你告诉我为什么我们需要使用两个'^'符号。



我的理解是'^'表示指针。



能告诉我如何解释和推断下面的表达。

Hi ,

I have the following code in C++/CLI in my code base.

Could you please let me know why we need to use two '^' symbols.

My understanding is '^' denotes a pointer .

Could you please let me know how to interpret and infer the below expression.

List<TopicDetails^>  ^subscriptionTopicDetails = gcnew List<TopicDetails^>();

推荐答案

这是一个托管指针，与C＃或VB.NET中的引用类型引用相同。符号^本身被称为对象操作符的句柄：

https://msdn.microsoft.com/en-us/library/yk97tc08.aspx [ ^ ]。



托管指针的C ++ / CLI方法在.NET语言中是唯一的，因为可以在没有引用的情况下使用该对象，因为可以使用托管ref类型的变量名称直接引用该对象。与常规指针的类比表明了通常的堆栈对象存储，但令人惊讶的是，它是一种伪造的，并且无论如何都使用托管堆来完全模拟值语义。您可以在本出版物中阅读： http://www.gotw.ca/publications/C++CLIRationale .pdf [ ^ ]。



为什么代码片段中有两个^？试想一下：涉及两种不同的类型：列表类型（泛型 System :: Collecton :: Generic :: List<> 使用泛型实例化为完整类型type参数）和list元素的类型（在您的情况下，是一个泛型参数）。两者都是参考类型。

-SA

This is a managed pointer, same as reference-type reference in C# or VB.NET. The symbol ^ itself is called handle to object operator:
https://msdn.microsoft.com/en-us/library/yk97tc08.aspx[^].

C++/CLI approach to the managed pointers is unique among .NET language, because the object can be used without references, as the object can be referenced directly with name of a variable of the managed "ref" type. The analogy with "regular" pointer suggests the usual object-on-stack storage, but, surprisingly, it's a kind of fake, and the managed heap is used anyway with full simulation of value semantics. You can read about it in this publication: http://www.gotw.ca/publications/C++CLIRationale.pdf[^].

Why two ^ in your code fragment? Just think about it: two different types are involved: the list type (generic System::Collecton::Generic::List<> instantiated to a complete type using a generic type parameter) and the type of the list element (in your case, a generic parameter). Both are reference types.

—SA

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