空的初始化列表是有效的 C 代码吗? [英] Is an empty initializer list valid C code?

问题描述

通常使用 {0} 来初始化 struct 或 array 但考虑第一个字段不是标量类型.如果 struct Person 的第一个字段是另一个 struct 或数组，那么这一行会导致错误(error: missing brass around initializer).

It is common to use {0} to initialize a struct or an array but consider the case when the first field isn't a scalar type. If the first field of struct Person is another struct or array, then this line will result in an error (error: missing braces around initializer).

struct Person person = {0};

至少 GCC 允许我使用一个空的初始化列表来完成同样的事情

At least GCC allows me to use an empty initializer list to accomplish the same thing

struct Person person = {};

但这是有效的 C 代码吗?

But is this valid C code?

另外:这一行是否保证提供相同的行为，即零初始化的 struct?

Also: Is this line guaranteed to give the same behavior, i.e. a zero-initialized struct?

struct Person person;

推荐答案

否，不允许使用空的初始化列表.使用 -std=c99 -pedantic 编译时，GCC 也可以显示这一点:

No, an empty initializer list is not allowed. This can also be shown by GCC when compiling with -std=c99 -pedantic:

a.c:4: warning: ISO C forbids empty initializer braces

原因是2011 ISO C 标准:

initializer:
         assignment-expression
         { initializer-list }
         { initializer-list , }
initializer-list:
         designation(opt) initializer
         initializer-list , designation(opt) initializer

根据该定义，一个初始化列表必须至少包含一个初始化.

According to that definition, an initializer-list must contain at least one initializer.

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