Sleeps for a specified number of seconds.
secs (scalar) – number of seconds to sleep.
unslept (scalar) – number of seconds not slept.
secs does not have to be an integer. If your system does not permit sleeping for a fractional number of seconds, secs will be rounded to the nearest integer, with a minimum value of 1.
If a program sleeps for the full number of secs specified,
0; otherwise, if the program is awakened early (e.g., by a signal),
sleep() returns the amount of time not slept.
A program may sleep for longer than secs seconds, due to system scheduling.