v7 man page for sleep

SLEEP(3)						     Library Functions Manual							  SLEEP(3)

NAME
       sleep - suspend execution for interval

SYNOPSIS
       sleep(seconds)
       unsigned seconds;

DESCRIPTION
       The  current process is suspended from execution for the number of seconds specified by the argument.  The actual suspension time may be up
       to 1 second less than that requested, because scheduled wakeups occur at fixed 1-second intervals, and an arbitrary amount  longer  because
       of other activity in the system.

       The  routine  is  implemented by setting an alarm clock signal and pausing until it occurs.  The previous state of this signal is saved and
       restored.  If the sleep time exceeds the time to the alarm signal, the process sleeps only until the signal would have  occurred,  and  the
       signal is sent 1 second later.

SEE ALSO
       alarm(2), pause(2)

																	  SLEEP(3)