c - 声明一个同时具有寄存器和静态存储类的变量

Question

(ANSI-C 89) 您好，是否可以同时声明一个变量 static 和 register ？每当我尝试这样做时，我都会收到一条错误提示:multiple storage classes in declaration specifiers

这是代码:

#include <stdio.h>

void f1(static int i);
int main()
{
    static register int i;

    i = 5;
    f1(i);
}

void f1(static int i)
{
    static int y =6;
    y+=1;
    printf("\n Y=%d \n",y);
}

和那个

Answer 1

register和static都是存储类说明符，最多只能指定一个存储类说明符。

来自 C11 标准 ISO/IEC 9899:2011:

6.7.1 Storage-class specifiers

Syntax

1.      storage-class-specifier:
             typedef
          extern
          static
          _Thread_local
          auto
          register
   

Constraints

2. At most, one storage-class specifier may be given in the declaration specifiers in a declaration, except that _Thread_local may appear with static or extern.¹²⁰⁾

---

¹²⁰⁾_{See ‘‘future language directions’’ (6.11.5).}