C语言库函数(K类字母)

　　函数名: kbhit

　　功 能: 检查当前按下的键

　　用 法: int kbhit(void);

　　程序例:

　　#include

　　int main(void)

　　{

　　 cprintf("Press any key to continue:");

　　 while (!kbhit()) /* do nothing */ ;

　　 cprintf("

A key was pressed...

");

　　 return 0;

　　}

　　函数名: keep

　　功 能: 退出并继续驻留

　　用 法: void keep(int status, int size);

　　程序例:

　　/***NOTE:

　　 This is an interrupt service routine. You

　　 can NOT compile this program with Test

　　 Stack Overflow turned on and get an

　　 executable file which will operate

　　 correctly. Due to the nature of this

　　 function the formula used to compute

　　 the number of paragraphs may not

　　 necessarily work in all cases. Use with

　　 care! Terminate Stay Resident (TSR)

　　 programs are complex and no other support

　　 for them is provided. Refer to the

　　 MS-DOS technical documentation

　　 for more information. */

　　#include

　　/* The clock tick interrupt */

　　#define INTR 0x1C

　　/* Screen attribute (blue on grey) */

　　#define ATTR 0x7900

　　/* redUCe heaplength and stacklength

　　to make a smaller program in memory */

　　extern unsigned _heaplen = 1024;

　　extern unsigned _stklen = 512;

　　void interrupt ( *oldhandler)(void);

　　void interrupt handler(void)

　　{

　　 unsigned int (far *screen)[80];

　　 static int count;

　　/* For a color screen the video memory

　　 is at B800:0000. For a monochrome

　　 system use B000:000 */

　　 screen = MK_FP(0xB800,0);

　　/* increase the counter and keep it

　　 within 0 to 9 */

　　 count++;

　　 count %= 10;

　　/* put the number on the screen */

　　 screen[0][79] = count + '0' + ATTR;

　　/* call the old interrupt handler */

　　 oldhandler();

　　}

　　int main(void)

　　{

　　/* get the address of the current clock

　　 tick interrupt */

　　oldhandler = getvect(INTR);

　　/* install the new interrupt handler */

　　setvect(INTR, handler);

　　/* _psp is the starting address of the

　　 program in memory. The top of the stack

　　 is the end of the program. Using _SS and

　　 _SP together we can get the end of the

　　 stack. You may want to allow a bit of

　　 saftey space to insure that enough room

　　 is being allocated ie:

　　 (_SS + ((_SP + safety space)/16) - _psp)

　　*/

　　keep(0, (_SS + (_SP/16) - _psp));

　　return 0;

　　}