1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)gethostname.3 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD$ 34.\" 35.Dd August 18, 2003 36.Dt GETHOSTNAME 3 37.Os 38.Sh NAME 39.Nm gethostname , 40.Nm sethostname 41.Nd get/set name of current host 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In unistd.h 46.Ft int 47.Fn gethostname "char *name" "size_t namelen" 48.Ft int 49.Fn sethostname "const char *name" "int namelen" 50.Sh DESCRIPTION 51The 52.Fn gethostname 53function 54returns the standard host name for the current processor, as 55previously set by 56.Fn sethostname . 57The 58.Fa namelen 59argument 60specifies the size of the 61.Fa name 62array. 63The returned name is null-terminated unless insufficient space is provided. 64.Pp 65The 66.Fn sethostname 67function 68sets the name of the host machine to be 69.Fa name , 70which has length 71.Fa namelen . 72This call is restricted to the super-user and 73is normally used only when the system is bootstrapped. 74.Pp 75Host names are limited to 76.Brq Dv HOST_NAME_MAX 77characters, not including the trailing null, currently 255. 78.Sh RETURN VALUES 79.Rv -std 80.Sh ERRORS 81The following errors may be returned by these calls: 82.Bl -tag -width Er 83.It Bq Er EFAULT 84The 85.Fa name 86or 87.Fa namelen 88argument gave an 89invalid address. 90.It Bq Er ENAMETOOLONG 91The current host name is longer than 92.Fa namelen . (For 93.Fn gethostname 94only.) 95.It Bq Er EPERM 96The caller tried to set the host name and was not the super-user. 97.El 98.Sh SEE ALSO 99.Xr sysconf 3 , 100.Xr sysctl 3 101.Sh STANDARDS 102The 103.Fn gethostname 104function conforms to 105.St -p1003.1-2001 . 106Callers should be aware that 107.Brq Dv HOST_NAME_MAX 108may be variable or infinite, but is guaranteed to be no less than 109.Brq Dv _POSIX_HOST_NAME_MAX . 110On older systems, this limit was defined in the non-standard header 111.In sys/param.h 112as 113.Dv MAXHOSTNAMELEN , 114and counted the terminating null. 115The 116.Fn sethostname 117function and the error returns for 118.Fn gethostname 119are not standardized. 120.Sh HISTORY 121The 122.Fn gethostname 123function appeared in 124.Bx 4.2 . 125The 126.Fa namelen 127argument to 128.Fn gethostname 129was changed to 130.Vt size_t 131in 132.Fx 5.2 133for alignment with 134.St -p1003.1-2001 . 135