#include <stdio.h>
#include <sys/time.h>
#include <signal.h>

/* cranking the clock speed up too high causes problems with in handling the 
   interrupts.  Half-second seems good. */
#define CLOCK 1000		/* time between ticks: given in ms */

void NullRoutine()
{
    signal(SIGALRM, NullRoutine); /* do nothing on an alarm, not the same as SIG_IGN */
}

myclock(int ppid)
{
    struct itimerval itimer;

    signal(SIGALRM, NullRoutine); /* do nothing on an alarm, not the same as SIG_IGN */
    itimer.it_interval.tv_sec = CLOCK/1000;
    itimer.it_interval.tv_usec = (CLOCK*1000)%1000000;
    itimer.it_value.tv_sec = CLOCK/1000;
    itimer.it_value.tv_usec = (CLOCK*1000)%1000000;
    setitimer(ITIMER_REAL, &itimer, 0);
    while (1) {
	sigpause(0);
	kill(ppid, SIGALRM);
    }
}