当C struct是盒装类型时,C struct是unboxed吗？

发布时间：2020-12-16 10:30:52 所属栏目：百科来源：网络整理

导读：正如许多书中提到的,与C struct和class的区别在于访问控制描述符.因此,我想知道以下陈述是否正确： struct in C is unboxed: members in the struct are plainly located next to where the struct is allocated. But struct in C++ is a boxed type like cl

正如许多书中提到的,与C struct和class的区别在于访问控制描述符.因此,我想知道以下陈述是否正确：

struct in C is unboxed: members in the struct are plainly located next to where the struct is allocated.
But struct in C++ is a boxed type like class: members/headers are located somewhere else,and where the struct is allocated contains a pointer to the members/headers.

这种理解对吗？

是否可以在C中创建一个包含实例方法的未装箱类型？

解决方法

此讨论中缺少的关键字是“POD”( Plain Old Data structure). (拳击与.NET和可能的Java有关 – 虽然我不记得使用这个词的Java术语)

POD基本上意味着它可以通过’blitting bits'(memcpy,memmov)在内存中移动. C标准规范中有明确的要求.

C结构总是POD(普通旧数据),而C类可以具有与(虚拟)继承相关的“额外魔法”.

看这个：

What are POD types in C++?

（编辑：李大同）

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