.\"	$OpenBSD: nanosleep.2,v 1.3 1999/05/23 14:10:55 aaron Exp $
.\"	$NetBSD: nanosleep.2,v 1.1 1997/04/17 18:12:02 jtc Exp $
.\"
.\" Copyright (c) 1986, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)sleep.3	8.1 (Berkeley) 6/4/93
.\"
.Dd April 17, 1997
.Dt NANOSLEEP 2
.Os
.Sh NAME
.Nm nanosleep
.Nd high resolution sleep
.Sh SYNOPSIS
.Fd #include <time.h>
.Ft int
.Fn nanosleep "const struct timespec *rqtp" "struct timespec *rmtp"
.Sh DESCRIPTION
.Fn nanosleep
suspends execution of the calling process for the time specified. An unmasked
signal will cause it to terminate the sleep early, regardless of the
.Dv SA_RESTART
value on the interrupting signal.
.Sh RETURN VALUE
If the 
.Fn nanosleep
function returns because the requested time has elapsed, the value
returned will be zero.  
.Pp
If the 
.Fn nanosleep
function returns due to the delivery of a signal, the value returned
will be the -1, and the global variable
.Va errno
will be set to indicate the interruption.
If 
.Fa rmtp
is 
.Pf non- Dv NULL ,
the timespec structure it references is updated to contain the
unslept amount (the request time minus the time actually slept).
.Sh ERRORS
If any of the following conditions occur, the
.Nm 
function shall return -1 and set
.Va errno
to the corresponding value.
.Bl -tag -width Er
.It Bq Er EFAULT
Either
.Fa rqtp
or 
.Fa rmtp
points to memory that is not a valid part of the process
address space.
.It Bq Er EINTR
.Nm
was interrupted by the delivery of a signal.
.It Bq Er EINVAL
.Fa rqtp
specified a nanosecond value less than zero or greater than 1000 million.
.It Bq Er ENOSYS
.Nm
is not supported by this implementation.
.El
.Sh SEE ALSO
.Xr sleep 3
.Sh STANDARDS
The
.Fn nanosleep
function conforms to
.St -p1003.1b-93 .