为什么 ANSI C 没有命名空间? [英] Why doesn't ANSI C have namespaces?

问题描述

对于大多数语言来说，拥有命名空间似乎是轻而易举的事.但据我所知，ANSI C 不支持它.为什么不?是否有计划将其包含在未来的标准中?

Having namespaces seems like no-brainer for most languages. But as far as I can tell, ANSI C doesn't support it. Why not? Any plans to include it in a future standard?

推荐答案

C 确实有命名空间.一种用于结构标签，一种用于其他类型.考虑以下定义:

C does have namespaces. One for structure tags, and one for other types. Consider the following definition:

struct foo
{
    int a;
};

typedef struct bar
{
    int a;
} foo;

第一个有tag foo，后一个用typedef做成类型foo.仍然没有发生名称冲突.这是因为结构标签和类型(内置类型和 typedef 的类型)存在于不同的命名空间中.

The first one has tag foo, and the later is made into type foo with a typedef. Still no name-clashing happens. This is because structure tags and types (built-in types and typedef'ed types) live in separate namespaces.

C 不允许随意创建 new 命名空间.C 在被认为在语言中很重要之前已经标准化，并且添加名称空间也会威胁向后兼容性，因为它需要名称修改才能正常工作.我认为这可以归因于技术问题，而不是哲学.

What C doesn't allow is to create new namespace by will. C was standardized before this was deemed important in a language, and adding namespaces would also threaten backwards-compatibility, because it requires name mangling to work right. I think this can be attributed due to technicalities, not philosophy.

JeremyP 幸运地纠正了我并提到了我错过的命名空间.标签和结构/联合成员也有命名空间.

JeremyP fortunately corrected me and mentioned the namespaces I missed. There are namespaces for labels and for struct/union members as well.

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