/***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. */
#include <stdio.h>
#include <dos.h>
#include <conio.h>
#define INTR 0X1C /* The clock tick interrupt */
void interrupt ( *oldhandler)(void);
int count=0;
void interrupt handler(void)
{
/* increase the global counter */
count++;
/* call the old routine */
oldhandler();
}
int main(void)
{
/* save the old interrupt vector */
oldhandler = getvect(INTR);
/* install the new interrupt handler */
setvect(INTR, handler);
/* loop until the counter exceeds 20 */
while (count < 20)
printf("count is %d\n",count
);
/* reset the old interrupt handler */
setvect(INTR, oldhandler);
return 0;
}