C 预处理指令

#error

编译到此处时，会保存，导致中断编译

#error can not come here

int main()
{
    return 0;
}

$ gcc test.c
test.c:5:2: error: #error can not come here
 #error can not come here

参考文档：

https://github.com/kokke/tiny-AES-c