xref: /dragonfly/lib/libc/sys/nanosleep.2 (revision cfd1aba3)
1.\" $FreeBSD: src/lib/libc/sys/nanosleep.2,v 1.8.2.5 2002/12/20 18:39:35 ceri Exp $
2.\" $DragonFly: src/lib/libc/sys/nanosleep.2,v 1.2 2003/06/17 04:26:47 dillon Exp $
3.\"	$OpenBSD: nanosleep.2,v 1.1 1997/04/20 20:56:20 tholo Exp $
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33.\"     @(#)sleep.3	8.1 (Berkeley) 6/4/93
34.\"
35.Dd April 17, 1997
36.Dt NANOSLEEP 2
37.Os
38.Sh NAME
39.Nm nanosleep
40.Nd suspend process execution for an interval measured in nanoseconds
41.Sh LIBRARY
42.Lb libc
43.Sh SYNOPSIS
44.In time.h
45.Ft int
46.Fn nanosleep "const struct timespec *rqtp" "struct timespec *rmtp"
47.Sh DESCRIPTION
48.Fn Nanosleep
49causes the process to sleep for the specified time.  An unmasked signal will
50cause it to terminate the sleep early, regardless of the
51.Dv SA_RESTART
52value on the interrupting signal.
53.Sh RETURN VALUES
54If the
55.Fn nanosleep
56function returns because the requested time has elapsed, the value
57returned will be zero.
58.Pp
59If the
60.Fn nanosleep
61function returns due to the delivery of a signal, the value returned
62will be -1, and the global variable
63.Va errno
64will be set to indicate the interruption.
65If
66.Fa rmtp
67is
68.Pf non- Dv NULL ,
69the timespec structure it references is updated to contain the
70unslept amount (the request time minus the time actually slept).
71.Sh ERRORS
72The
73.Fn nanosleep
74call fails if:
75.Bl -tag -width Er
76.It Bq Er EFAULT
77Either
78.Fa rqtp
79or
80.Fa rmtp
81points to memory that is not a valid part of the process
82address space.
83.It Bq Er EINTR
84.Fn nanosleep
85was interrupted by the delivery of a signal.
86.It Bq Er EINVAL
87.Fa rqtp
88specified a nanosecond value less than zero
89or greater than or equal to 1000 million.
90.It Bq Er ENOSYS
91.Fn nanosleep
92is not supported by this implementation.
93.El
94.Sh SEE ALSO
95.Xr sigsuspend 2 ,
96.Xr sleep 3
97.Sh STANDARDS
98The
99.Fn nanosleep
100function conforms to
101.St -p1003.1b-93 .
102