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SLEEP(3)		     Library Functions Manual			SLEEP(3)

NAME
     sleep -- suspend thread execution for an interval measured in seconds

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <unistd.h>

     unsigned int
     sleep(unsigned int seconds);

DESCRIPTION
     The  sleep() function suspends execution of the calling thread until either
     seconds seconds have elapsed or a signal is delivered to the thread and its
     action is to invoke a signal-catching function or to terminate  the  thread
     or  process.   System  activity  may lengthen the sleep by an indeterminate
     amount.

     This function is implemented using nanosleep(2) by pausing for seconds sec-
     onds or until a  signal  occurs.	Consequently,  in  this  implementation,
     sleeping has no effect on the state of process timers, and there is no spe-
     cial handling for SIGALRM.

RETURN VALUES
     If the sleep() function returns because the requested time has elapsed, the
     value  returned  will  be zero.  If the sleep() function returns due to the
     delivery of a signal, the value returned will be the  unslept  amount  (the
     requested time minus the time actually slept) in seconds.

SEE ALSO
     nanosleep(2), usleep(3)

STANDARDS
     The sleep() function conforms to ISO/IEC 9945-1:1990 ("POSIX.1").

HISTORY
     A sleep() function appeared in Version 7 AT&T UNIX.

FreeBSD ports 15.1		February 13, 1998			SLEEP(3)

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<https://man.freebsd.org/cgi/man.cgi?query=sleep&sektion=3&manpath=FreeBSD+15.1-RELEASE+and+Ports>

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