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[dragonfly.git] / lib / libc / gen / sleep.3
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32.\" @(#)sleep.3 8.1 (Berkeley) 6/4/93
33.\" $FreeBSD: src/lib/libc/gen/sleep.3,v 1.12.2.3 2001/12/14 18:33:51 ru Exp $
1de703da 34.\" $DragonFly: src/lib/libc/gen/sleep.3,v 1.2 2003/06/17 04:26:42 dillon Exp $
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35.\"
36.Dd February 13, 1998
37.Dt SLEEP 3
38.Os
39.Sh NAME
40.Nm sleep
41.Nd suspend process execution for an interval measured in seconds
42.Sh LIBRARY
43.Lb libc
44.Sh SYNOPSIS
45.In unistd.h
46.Ft unsigned int
47.Fn sleep "unsigned int seconds"
48.Sh DESCRIPTION
49The
50.Fn sleep
51function suspends execution of the calling process until either
52.Fa seconds
53seconds have elapsed or a signal is delivered to the process and its
54action is to invoke a signal-catching function or to terminate the
55process.
56System activity may lengthen the sleep by an indeterminate amount.
57.Pp
58This function is implemented using
59.Xr nanosleep 2
60by pausing for
61.Fa seconds
62seconds or until a signal occurs.
63Consequently, in this implementation,
64sleeping has no effect on the state of process timers,
65and there is no special handling for SIGALRM.
66.Sh RETURN VALUES
67If the
68.Fn sleep
69function returns because the requested time has elapsed, the value
70returned will be zero. If the
71.Fn sleep
72function returns due to the delivery of a signal, the value returned
73will be the unslept amount (the requested time minus the time actually
74slept) in seconds.
75.Sh SEE ALSO
76.Xr nanosleep 2 ,
77.Xr usleep 3
78.Sh STANDARDS
79The
80.Fn sleep
81function conforms to
82.St -p1003.1-90 .
83.Sh HISTORY
84A
85.Fn sleep
86function appeared in
87.At v7 .