C程序开头的#include<conio.h>调用的库函数的内容是什么?

#include<conio.h>
简单说就是“通用输入输出库”，主要是文件和标准控制台的输入输出
最常用的比如 getch();clrscr()
具体一些就是楼上所说

/* 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 */