请高手帮我详细注释一下这个头文件,谢谢~

来源:百度知道 编辑:UC知道 时间:2024/06/02 01:20:33
大家来讨论一下类试这种头文件为什么要这样写。。。

/* conio.h

Direct MSDOS console input/output.

Copyright (c) Borland International 1987,1988
All Rights Reserved.
*/
#if !defined(__VIDEO)
#define __VIDEO

#if __STDC__
#define _Cdecl
#else
#define _Cdecl cdecl
#endif

#ifndef __OLDCONIO__

struct text_info {
unsigned char winleft;
unsigned char wintop;
unsigned char winright;
unsigned char winbottom;
unsigned char attribute;
unsigned char normattr;
unsigned char currmode;
unsigned char screenheight;
unsigned char screenwidth;
unsigned char curx;
unsigned char cury;
};

enum text_modes { LASTMODE=-1, BW40=0, C40, BW80, C80, MONO=7 };

#if !defined(__COLORS)
#define __COLORS

enum COLORS {
BLACK, /* dark colors */
BLUE,
GREEN,
CYAN,
RED,
MAGENTA,
BROWN,
LI

这么写的目的是防止,重复宏定义

#if _STDC
#define _Cdecl
#else
#define _Cdecl cdecl
#endif
上面代码的意识是如果存在了_STDC则定义_Cdecl否则定义_Cdecl cdecl

#if !defined(__VIDEO)
表示如果还没有宏定义_VIDEO执行下面的代码