是的typedef存储类说明符？ [英] Is typedef a storage-class-specifier?

问题描述

我尝试以下code

#include <stdio.h>

int main(void)
{
    typedef static int sint;
    sint i = 10;

    return 0;
}

和命中以下错误：

error: multiple storage classes in declaration specifiers

当我提到的C99规范，我才知道，的typedef 是存储类。

When I referred the C99 specification, I came to know that typedef is a storage class.

6.7.1 Storage-class specifiers

Syntax

storage-class-specifier:
    typedef
    extern
    static
    auto
    register

Constraints: At most, one storage-class specifier may be 
             given in the declaration specifiers in a declaration

Semantics: The typedef specifier is called a ‘‘storage-class specifier’’ 
           for syntactic convenience only; 

（基于一些互联网搜索和交叉在C99规格指各部分），我能找到的唯一解释是语法上的方便才使语法简单。

我在找一些理由/解释上的类型名称怎么能有存储类说明？

I'm looking for some justification/explanation on how can a type name have storage class specifier?

不有意义有一个code像的typedef静态INT SINT;

Doesn't it make sense to have a code like typedef static int sint;?

或我在哪里去了？！

推荐答案

是的typedef 是一个存储类说明符如您在标准中。在某种程度上这是一个语法上的便利，但它是经过深思熟虑的，你可以有的typedef 的或的比较明显的存储类说明符之一。

Yes, typedef is a storage-class-specifier as you found in the standard. In part it's a grammatical convenience, but it is deliberate that you can either have typedef or one of the more "obvious" storage class specifiers.

一个typedef声明的类型创建一个别名。

A typedef declaration creates an alias for a type.

在声明静态INT X; 类型X 是 INT 。 静态无关的类型。

In a declaration static int x; the type of x is int. static has nothing to do with the type.

（想想看，如果你把 X ，＆安培的地址; X 的类型为int * 为int * Y =＆放大器; X; 将是合法的，因为会静态INT * Z =＆放大器; X ，但后者静态影响存储类以Z ，并且是独立于存储的类 X ）

(Consider that if you take the address of x, &x has type int*. int *y = &x; would be legal as would static int *z = &x but this latter static affects the storage class of z and is independent of the storage class of x.)

如果像这样被允许的静态将不得不为没有对象被宣布无效。被别名的类型只是 INT 。

If something like this were allowed the static would have no effect as no object is being declared. The type being aliased is just int.

typedef static int sint;

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