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.\" $OpenBSD: gethostname.3,v 1.23 2007/05/31 19:19:28 jmc Exp $
.\"
.\" Copyright (c) 1983, 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. 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.
.\"
.Dd $Mdocdate: May 31 2007 $
.Dt GETHOSTNAME 3
.Os
.Sh NAME
.Nm gethostname ,
.Nm sethostname
.Nd get/set name of current host
.Sh SYNOPSIS
.Fd #include <unistd.h>
.Ft int
.Fn gethostname "char *name" "size_t namelen"
.Ft int
.Fn sethostname "const char *name" "size_t namelen"
.Sh DESCRIPTION
The
.Fn gethostname
function returns the standard host name for the current
processor, as previously set by
.Fn sethostname .
The parameter
.Fa namelen
specifies the size of the
.Fa name
array.
If insufficient space is provided, the returned name is truncated.
The returned name is always NUL terminated.
If no space is provided, an error is returned.
.Pp
.Fn sethostname
sets the name of the host machine to be
.Fa name ,
which has length
.Fa namelen .
This call is restricted to the superuser and
is normally used only when the system is bootstrapped.
.Sh RETURN VALUES
If the call succeeds a value of 0 is returned.
If the call fails, a value of \-1 is returned and an error code is
placed in the global variable
.Va errno .
.Sh ERRORS
The following errors may be returned by these calls:
.Bl -tag -width Er
.It Bq Er EFAULT
The
.Fa name
parameter gave an invalid address.
.It Bq Er ENOMEM
The
.Ar namelen
parameter was zero.
.It Bq Er EPERM
The caller tried to set the hostname and was not the superuser.
.El
.Sh SEE ALSO
.Xr hostname 1 ,
.Xr getdomainname 3 ,
.Xr gethostid 3 ,
.Xr sysctl 3 ,
.Xr sysctl 8 ,
.Xr yp 8
.Sh STANDARDS
The
.Fn gethostname
function call conforms to
.St -xpg4.2 .
.Sh HISTORY
The
.Fn gethostname
function call appeared in
.Bx 4.2 .
.Sh BUGS
Host names are limited to
.Dv MAXHOSTNAMELEN
(from
.Ao Pa sys/param.h Ac )
characters, currently 256.
This includes the terminating NUL character.
.Pp
If the buffer passed to
.Fn gethostname
is smaller than
.Dv MAXHOSTNAMELEN ,
other operating systems may not guarantee termination with NUL.
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