结构声明数组c [英] C array of structs declaration

问题描述

在Linux内核中，我看到结构的数组，看起来像这样的声明

In the Linux kernel, I see a declaration of an array of structs that looks like this

struct SomeStructName [] ={
[SOMEWEIRD_NAME] = {
                   .field1 = "some value"
                   },
[SOMEWEIRD_NAME2] = {
                   .field1 = "some value1"
                   },
}

我从来没有见过这样的声明，具体我也弄不清是什么 [SOMEWEIRD_NAME] 表示，为什么它的使用。

I have never seen a declaration like that, specifically I can't figure out what [SOMEWEIRD_NAME] means, and why it's used.

推荐答案

这是一个C99的 指定的初始化 的数组。

It's a C99 designated initializer for arrays.

例如：

/* 
 * Initialize element  0 to 1
 *                     1 to 2
 *                     2 to 3
 *                   255 to 1   
 * and all other elements to 0
 */
int arr[256] = {[0] = 1, 2, 3, [255] = 1};

它允许你初始化任何顺序一些具体的数组元素，也可以让你忽略一些元素。

It allows you to initialize some specific array elements in any order and also allows you to omit some elements.

在你的榜样之间的前pression [] 可以是一个整型常量前pression或宏名枚举不变。它不能是一个变量名，因为它必须是一个整型常量前pression。

In your example the expression between [] can be a macro name for an integer constant expression or an enum constant. It cannot be a variable name as it has to be an integer constant expression.

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