freebsd-nq/lib/libc/gen/sleep.3
1997-10-16 13:42:03 +00:00

91 lines
3.1 KiB
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.\" @(#)sleep.3 8.1 (Berkeley) 6/4/93
.\"
.Dd June 4, 1993
.Dt SLEEP 3
.Os
.Sh NAME
.Nm sleep
.Nd suspend process execution for interval of seconds
.Sh SYNOPSIS
.Fd #include <unistd.h>
.Ft u_int
.Fn sleep "u_int seconds"
.Sh DESCRIPTION
The
.Fn sleep
function
suspends execution of the calling process
for
.Fa seconds
of time.
System activity or time spent in processing the
call may lengthen the sleep by a second.
.Pp
If a timer is already running on the process its state is unaltered by
this
.Fn sleep
implementation.
If the value
.Fa seconds
is more than or equal to the remaining clock time for the running timer,
the sleep time is set to
the remaining clock time.
.Pp
This function is implemented using
.Xr nanosleep 2
by pausing for
.Fa seconds
of time or until any signal occurse.
.Sh RETURN VALUES
The
.Fn sleep
function returns the number of seconds remaining to complete the operation. If
sleep is interrupted or cannot allocate a timer it may will return the value
needed to be passed to a subsequent sleep to complete the necessary delay.
.Fn sleep
repeatedly until it returns zero may busy-wait until a timer
is available.
.Sh SEE ALSO
.Xr nanosleep 2 ,
.Xr setitimer 2 ,
.Xr alarm 3 ,
.Xr signal 3 ,
.Xr ualarm 3 ,
.Xr usleep 3
.Sh HISTORY
A
.Fn sleep
function appeared in
.At v7 .