sleep - suspend execution for interval
#include <sys.h>
The current thread is suspended from execution for the number of seconds^ specified by the argument. The actual suspension time may be less than that requested because any caught signal will terminate the sleep() following execution of that signal's catching routine. Also, the suspension time may be longer than requested by an arbitrary amount because of the scheduling of other activity in the system.
Always returns 0 on success but may return -1 if timer not setup.