确实结构与单个构件具有相同的性能作为一个部件类型？ [英] Does struct with a single member have the same performance as a member type?

问题描述

确实结构与单个成员具有相同的性能成为会员类型（内存使用和速度）？

Does struct with a single member have the same performance as a member type (memory usage and speed)?

示例

这code是结构有一个成员：

This code is a struct with a single member:

struct my_int
{
    int value;
};

时的表现 my_int 相同 INT ？

推荐答案

同意@harper整体，但要注意以下几点：

Agree with @harper overall, but watch out for the following:

一个经典的差异被认为是与结构的非结构化阵列和阵列。

A classic difference is seen with a "unstructured" array and an array in a structure.

char s1[1000];
// vs
typedef struct {
  char s2[1000];
} s_T;
s_T s3;

当调用函数

void f1(char s[1000]);
void f2(s_T s);
void f3(s_T *s);

// Significant performance difference is not expected.
// In both, only an address is passed.
f1(s1);
f1(s3.s2);

// Significant performance difference is expected.
// In the second case, a copy of the entire structure is passed.
// This style of parameter passing is usually frowned upon.
f1(s1);
f2(s3);

// Significant performance difference is not expected.
// In both, only an address is passed.
f1(s1);
f3(&s3);

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