宏观困惑

Question

下面的代码可以正常工作

#define open {
#define close }
#include<stdio.h>
#define int char

 main()
 open
 int a ;
 printf("This is testing code" );
 close

但是如果我换行

#include<stdio.h>
#define int char 

作为

#define int char 
#include<stdio.h> 

它会抛出很多这样的错误

In file included from /usr/include/stdio.h:36,
                 from print.c:19:
/usr/include/bits/types.h:35: error: both 'short' and 'char' in declaration specifiers
/usr/include/bits/types.h:37: error: both 'long' and 'char' in declaration specifiers
/usr/include/bits/types.h:42: error: both 'short' and 'char' in declaration specifiers
/usr/include/bits/types.h:43: error: both 'short' and 'char' in declaration specifiers
.................................................
so and so 

实际上 stdio.h 中发生了什么？

Answer 1

定义了short int、long int等类型的变量，通过define改成short char显然失败了> 和 long char。

重新定义基本的 C 类型通常不是一个好主意。