函数名:peekb
功 能: 检查存储单元
用 法:char peekb (int segment, unsigned offset);
segment为段基地址，offset偏移地址。
程序例:
#include <stdio.h>
#include <conio.h>
#include <dos.h>
int main(void)
{
int value = 0;
printf("The current status of your keyboard is:
");
value = peekb(0x0040, 0x0017);
if (value & 1)
printf("Right shift on
");
else
printf("Right shift off
");
if (value & 2)
printf("Left shift on
");
else
printf("Left shift off
");
if (value & 4)
printf("Control key on
");
else
printf("Control key off
");
if (value & 8)
printf("Alt key on
");
else
printf("Alt key off
");
if (value & 16)
printf("Scroll lock on
");
else
printf("Scroll lock off
");
if (value & 32)
printf("Num lock on
");
else
printf("Num lock off
");
if (value & 64)
printf("Caps lock on
");
else
printf("Caps lock off
");
return 0;
}