Timer values are defined by the following structures:
struct itimerval {
struct timeval it_interval; /* next value */
struct timeval it_value; /* current value */
};
struct timeval {
long tv_sec; /* seconds */
long tv_usec; /* microseconds */
};
Getitimer(2) fills the structure indicated by value with the current setting for
the timer indicated by which (one of ITIMER_REAL, ITIMER_VIRTUAL, or ITIMER_PROF).
The element it_value is set to the amount of time remaining on the timer, or zero
if the timer is disabled. Similarly, it_interval is set to the reset value.
Setitimer(2) sets the indicated timer to the value in value. If ovalue is nonzero,
the old value of the timer is stored there.