如何使用C编程语言实际实现结构? [英] How are structs actually implemented in the C programming language?

问题描述

结构是C编程语言中的复合数据结构；它们由诸如整数和指针之类的原语组成，它们全部以相邻的方式(如数组)放置在内存中.

Structs are a composite data structure in the C programming language; they consist of primitives such as ints and pointers all placed in memory in an adjacent fashion, such as an array.

我的问题是，结构本身是由什么制成的?它们是数组的类型吗?例如，哈希表可以实现为链接列表的数组.以类似的方式，将结构实现为什么? 如果需要，请在x86汇编程序级别进行解释.谢谢.

My question is, what are structs themselves made out of? Are they a type of array? For example, a hash table can be implemented as an array of linked-lists. In a similar way, what is a struct implemented as? If need be, please explain at the x86 assembly level. Thank you.

推荐答案

在程序集级别，结构归结为一个由对应于结构成员的偏移量访问的地址.

At assembly level Structure boils down to a address accessed by offset corresponding to structure member.

根据对齐规则，为结构实例分配存储类内存.

Depending on the alignment rule and storage class memory is allocated for instance of structure.

示例:

struct A
{
  int a,
  char b
}a1;

在上述情况下，如果您编写a1.b = 5，则它的程序集等效项将是:

In above case if you write a1.b = 5 its assembly equivalent would be something:

MOV 5 TO ADDRESS OF a1 + 4//假定整数大小为4

MOV 5 TO ADDRESS OF a1 + 4 //assuming integer size is 4

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