什么是点（。）在一个struct初始化是什么意思？ [英] What does dot (.) mean in a struct initializer?

问题描述

static struct fuse_oprations hello_oper = {
  .getattr = hello_getattr,
  .readdir = hello_readdir,
  .open    = hello_open,
  .read    = hello_read,
};

我不明白这个C语法很好。我甚至无法搜索，因为我不知道语法的名字。那是什么？

I don't understand this C syntax well. I can't even search because I don't know the syntax's name. What's that?

推荐答案

这是C99的功能，可以让你的名字在初始化设置结构的具体领域。在此之前，初始化需要只包含值，所有领域，为了 - 这仍然有效，当然，

This is a C99 feature that allows you to set specific fields of the struct by name in an initializer. Before this, the initializer needed to contain just the values, for all fields, in order -- which still works, of course.

因此​​，对于下面的结构：

So for the following struct:

struct demo_s {
  int     first;
  int     second;
  int     third;
};

...您可以使用

...you can use

struct demo_s demo = { 1, 2, 3 };

...或者：

struct demo_s demo = { .first = 1, .second = 2, .third = 3 };

...甚至是：

...or even:

struct demo_s demo = { .first = 1, .third = 3, .second = 2 };

...虽然最后两个用于C99只。

...though the last two are for C99 only.

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