ualarm - set interval timer

Syntax	#include <unistd.h> useconds_t ualarm(useconds_t useconds, useconds_t interval)
Description	ualarm() sends the SIGALRM signal to the calling process after useconds microseconds. Unless it is ignored or caught, the signal terminates the process. If the interval argument is not zero, the SIGALRM signal will be sent to the process every interval microseconds after expiry of the timer (e.g. after useconds microseconds have elapsed). Because of delays in the scheduling, the resumption of execution after the signal is caught can be delayed. The longest delay time that can be specified is 2.147.483.647 microseconds.
Return val.	The return value is the time remaining until the alarm signal is output.
Notes	ualarm() is a simplified interface for setitimer().
See also	alarm(), setitimer(), sleep(), unistd.h.