#include <stdio.h> 
#include <dos.h> 

void interrupt get_out(); /* interrupt prototype */ 

void interrupt (*oldfunc)(); /* interrupt function pointer */ 
int looping = 1; 

int main(void) 
{ 
  puts("Press <Shift><Prt Sc> to terminate"); 

  /* save the old interrupt */ 
  oldfunc  = getvect(5); 

   /* install interrupt handler */ 
  setvect(5,get_out); 

   /* do nothing */ 
  while (looping); 

   /* restore to original interrupt routine */ 
   setvect(5,oldfunc); 

  puts("Success"); 
  return 0; 
} 
void interrupt get_out() 
{ 
  looping = 0; /* change global variable to get out of loop */ 
}