conio.h：没有这样的文件或目录

Question

这是一个简单的c代码，我想在Ubuntu 12.04下编译

$ fgrep -n '' elso.c 
1:#include "stdio.h"
2:#include "conio.h"
3: 
4:void main()
5:{
6:  int w,h;
7:  int area;
8:  printf("\nEnter the width of the rectangle ");
9:  scanf("%d",&w);
10:  printf("\nEnter the height of the rectangle ");
11:  scanf("%d",&h);
12:  area=w*h;
13:  printf("\nThe area of a rectangle is %d",area);
14:getch();
15:}
$ gcc elso.c -o elso
elso.c:2:19: fatal error: conio.h: No such file or directory
compilation terminated.
$ head -1 /etc/issue
Ubuntu 12.04.3 LTS \n \l

问：什么是“致命错误：conio.h：没有这样的文件或目录”？