xref: /openbsd/lib/libc/sys/nanosleep.2 (revision 78b63d65)
1.\"	$OpenBSD: nanosleep.2,v 1.7 2000/10/18 05:12:10 aaron Exp $
2.\"	$NetBSD: nanosleep.2,v 1.1 1997/04/17 18:12:02 jtc Exp $
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35.\"     @(#)sleep.3	8.1 (Berkeley) 6/4/93
36.\"
37.Dd April 17, 1997
38.Dt NANOSLEEP 2
39.Os
40.Sh NAME
41.Nm nanosleep
42.Nd high resolution sleep
43.Sh SYNOPSIS
44.Fd #include <time.h>
45.Ft int
46.Fn nanosleep "const struct timespec *rqtp" "struct timespec *rmtp"
47.Sh DESCRIPTION
48.Fn nanosleep
49suspends execution of the calling process for the time specified.
50An unmasked signal will cause it to terminate the sleep early,
51regardless of the
52.Dv SA_RESTART
53value on the interrupting signal.
54.Sh RETURN VALUES
55If the
56.Fn nanosleep
57function returns because the requested time has elapsed, the value
58returned will be zero.
59.Pp
60If the
61.Fn nanosleep
62function returns due to the delivery of a signal, the value returned
63will be the \-1, and the global variable
64.Va errno
65will be set to indicate the interruption.
66If
67.Fa rmtp
68is non-null, the timespec structure it references is updated to contain the
69unslept amount (the request time minus the time actually slept).
70.Sh ERRORS
71If any of the following conditions occur, the
72.Fn nanosleep
73function shall return \-1 and set
74.Va errno
75to the corresponding value.
76.Bl -tag -width Er
77.It Bq Er EFAULT
78Either
79.Fa rqtp
80or
81.Fa rmtp
82points to memory that is not a valid part of the process address space.
83.It Bq Er EINTR
84.Nm
85was interrupted by the delivery of a signal.
86.It Bq Er EINVAL
87.Fa rqtp
88specified a nanosecond value less than zero or greater than 1000 million,
89or a second value less than zero or greater than 100 million.
90.It Bq Er ENOSYS
91.Nm
92is not supported by this implementation.
93.El
94.Sh SEE ALSO
95.Xr sleep 3
96.Sh STANDARDS
97The
98.Fn nanosleep
99function conforms to
100.St -p1003.1b-93 .
101